| /* Perform -*- C++ -*- constant expression evaluation, including calls to |
| constexpr functions. These routines are used both during actual parsing |
| and during the instantiation of template functions. |
| |
| Copyright (C) 1998-2023 Free Software Foundation, Inc. |
| |
| This file is part of GCC. |
| |
| GCC is free software; you can redistribute it and/or modify it |
| under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3, or (at your option) |
| any later version. |
| |
| GCC is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GCC; see the file COPYING3. If not see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "cp-tree.h" |
| #include "varasm.h" |
| #include "c-family/c-objc.h" |
| #include "tree-iterator.h" |
| #include "gimplify.h" |
| #include "builtins.h" |
| #include "tree-inline.h" |
| #include "ubsan.h" |
| #include "timevar.h" |
| #include "fold-const-call.h" |
| #include "stor-layout.h" |
| #include "cgraph.h" |
| #include "opts.h" |
| #include "stringpool.h" |
| #include "attribs.h" |
| #include "fold-const.h" |
| #include "intl.h" |
| |
| static bool verify_constant (tree, bool, bool *, bool *); |
| #define VERIFY_CONSTANT(X) \ |
| do { \ |
| if (verify_constant ((X), ctx->quiet, non_constant_p, overflow_p)) \ |
| return t; \ |
| } while (0) |
| |
| static HOST_WIDE_INT find_array_ctor_elt (tree ary, tree dindex, |
| bool insert = false); |
| static int array_index_cmp (tree key, tree index); |
| |
| /* Returns true iff FUN is an instantiation of a constexpr function |
| template or a defaulted constexpr function. */ |
| |
| bool |
| is_instantiation_of_constexpr (tree fun) |
| { |
| return ((DECL_TEMPLOID_INSTANTIATION (fun) |
| && DECL_DECLARED_CONSTEXPR_P (DECL_TI_TEMPLATE (fun))) |
| || (DECL_DEFAULTED_FN (fun) |
| && DECL_DECLARED_CONSTEXPR_P (fun))); |
| } |
| |
| /* Return true if T is a literal type. */ |
| |
| bool |
| literal_type_p (tree t) |
| { |
| if (SCALAR_TYPE_P (t) |
| || VECTOR_TYPE_P (t) |
| || TYPE_REF_P (t) |
| || (VOID_TYPE_P (t) && cxx_dialect >= cxx14)) |
| return true; |
| if (CLASS_TYPE_P (t)) |
| { |
| t = complete_type (t); |
| gcc_assert (COMPLETE_TYPE_P (t) || errorcount); |
| return CLASSTYPE_LITERAL_P (t); |
| } |
| if (TREE_CODE (t) == ARRAY_TYPE) |
| return literal_type_p (strip_array_types (t)); |
| return false; |
| } |
| |
| /* If DECL is a variable declared `constexpr', require its type |
| be literal. Return error_mark_node if we give an error, the |
| DECL otherwise. */ |
| |
| tree |
| ensure_literal_type_for_constexpr_object (tree decl) |
| { |
| tree type = TREE_TYPE (decl); |
| if (VAR_P (decl) |
| && (DECL_DECLARED_CONSTEXPR_P (decl) |
| || var_in_constexpr_fn (decl)) |
| && !processing_template_decl) |
| { |
| tree stype = strip_array_types (type); |
| if (CLASS_TYPE_P (stype) && !COMPLETE_TYPE_P (complete_type (stype))) |
| /* Don't complain here, we'll complain about incompleteness |
| when we try to initialize the variable. */; |
| else if (!literal_type_p (type)) |
| { |
| if (DECL_DECLARED_CONSTEXPR_P (decl)) |
| { |
| auto_diagnostic_group d; |
| error_at (DECL_SOURCE_LOCATION (decl), |
| "the type %qT of %<constexpr%> variable %qD " |
| "is not literal", type, decl); |
| explain_non_literal_class (type); |
| decl = error_mark_node; |
| } |
| else if (cxx_dialect < cxx23) |
| { |
| if (!is_instantiation_of_constexpr (current_function_decl)) |
| { |
| auto_diagnostic_group d; |
| error_at (DECL_SOURCE_LOCATION (decl), |
| "variable %qD of non-literal type %qT in " |
| "%<constexpr%> function only available with " |
| "%<-std=c++2b%> or %<-std=gnu++2b%>", decl, type); |
| explain_non_literal_class (type); |
| decl = error_mark_node; |
| } |
| cp_function_chain->invalid_constexpr = true; |
| } |
| } |
| else if (DECL_DECLARED_CONSTEXPR_P (decl) |
| && variably_modified_type_p (type, NULL_TREE)) |
| { |
| error_at (DECL_SOURCE_LOCATION (decl), |
| "%<constexpr%> variable %qD has variably-modified " |
| "type %qT", decl, type); |
| decl = error_mark_node; |
| } |
| } |
| return decl; |
| } |
| |
| /* Issue a diagnostic with text GMSGID for constructs that are invalid in |
| constexpr functions. CONSTEXPR_FUNDEF_P is true if we're checking |
| a constexpr function body; if so, don't report hard errors and issue |
| a pedwarn pre-C++23, or a warning in C++23, if requested by |
| -Winvalid-constexpr. Otherwise, we're not in the context where we are |
| checking if a function can be marked 'constexpr', so give a hard error. */ |
| |
| ATTRIBUTE_GCC_DIAG(3,4) |
| static bool |
| constexpr_error (location_t location, bool constexpr_fundef_p, |
| const char *gmsgid, ...) |
| { |
| diagnostic_info diagnostic; |
| va_list ap; |
| rich_location richloc (line_table, location); |
| va_start (ap, gmsgid); |
| bool ret; |
| if (!constexpr_fundef_p) |
| { |
| /* Report an error that cannot be suppressed. */ |
| diagnostic_set_info (&diagnostic, gmsgid, &ap, &richloc, DK_ERROR); |
| ret = diagnostic_report_diagnostic (global_dc, &diagnostic); |
| } |
| else if (warn_invalid_constexpr) |
| { |
| diagnostic_set_info (&diagnostic, gmsgid, &ap, &richloc, |
| cxx_dialect < cxx23 ? DK_PEDWARN : DK_WARNING); |
| diagnostic.option_index = OPT_Winvalid_constexpr; |
| ret = diagnostic_report_diagnostic (global_dc, &diagnostic); |
| } |
| else |
| ret = false; |
| va_end (ap); |
| return ret; |
| } |
| |
| struct constexpr_fundef_hasher : ggc_ptr_hash<constexpr_fundef> |
| { |
| static hashval_t hash (const constexpr_fundef *); |
| static bool equal (const constexpr_fundef *, const constexpr_fundef *); |
| }; |
| |
| /* This table holds all constexpr function definitions seen in |
| the current translation unit. */ |
| |
| static GTY (()) hash_table<constexpr_fundef_hasher> *constexpr_fundef_table; |
| |
| /* Utility function used for managing the constexpr function table. |
| Return true if the entries pointed to by P and Q are for the |
| same constexpr function. */ |
| |
| inline bool |
| constexpr_fundef_hasher::equal (const constexpr_fundef *lhs, |
| const constexpr_fundef *rhs) |
| { |
| return lhs->decl == rhs->decl; |
| } |
| |
| /* Utility function used for managing the constexpr function table. |
| Return a hash value for the entry pointed to by Q. */ |
| |
| inline hashval_t |
| constexpr_fundef_hasher::hash (const constexpr_fundef *fundef) |
| { |
| return DECL_UID (fundef->decl); |
| } |
| |
| /* Return a previously saved definition of function FUN. */ |
| |
| constexpr_fundef * |
| retrieve_constexpr_fundef (tree fun) |
| { |
| if (constexpr_fundef_table == NULL) |
| return NULL; |
| |
| constexpr_fundef fundef = { fun, NULL_TREE, NULL_TREE, NULL_TREE }; |
| return constexpr_fundef_table->find (&fundef); |
| } |
| |
| /* Check whether the parameter and return types of FUN are valid for a |
| constexpr function, and complain if COMPLAIN. */ |
| |
| bool |
| is_valid_constexpr_fn (tree fun, bool complain) |
| { |
| bool ret = true; |
| |
| if (DECL_INHERITED_CTOR (fun) |
| && TREE_CODE (fun) == TEMPLATE_DECL) |
| { |
| ret = false; |
| if (complain) |
| error ("inherited constructor %qD is not %<constexpr%>", |
| DECL_INHERITED_CTOR (fun)); |
| } |
| else |
| { |
| for (tree parm = FUNCTION_FIRST_USER_PARM (fun); |
| parm != NULL_TREE; parm = TREE_CHAIN (parm)) |
| if (!literal_type_p (TREE_TYPE (parm))) |
| { |
| ret = false; |
| if (complain) |
| { |
| auto_diagnostic_group d; |
| if (constexpr_error (input_location, /*constexpr_fundef_p*/true, |
| "invalid type for parameter %d of " |
| "%<constexpr%> function %q+#D", |
| DECL_PARM_INDEX (parm), fun)) |
| explain_non_literal_class (TREE_TYPE (parm)); |
| } |
| } |
| } |
| |
| if (LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) && cxx_dialect < cxx17) |
| { |
| ret = false; |
| if (complain) |
| inform (DECL_SOURCE_LOCATION (fun), |
| "lambdas are implicitly %<constexpr%> only in C++17 and later"); |
| } |
| else if (DECL_DESTRUCTOR_P (fun)) |
| { |
| if (cxx_dialect < cxx20) |
| { |
| ret = false; |
| if (complain) |
| error_at (DECL_SOURCE_LOCATION (fun), |
| "%<constexpr%> destructors only available" |
| " with %<-std=c++20%> or %<-std=gnu++20%>"); |
| } |
| } |
| else if (!DECL_CONSTRUCTOR_P (fun)) |
| { |
| tree rettype = TREE_TYPE (TREE_TYPE (fun)); |
| if (!literal_type_p (rettype)) |
| { |
| ret = false; |
| if (complain) |
| { |
| auto_diagnostic_group d; |
| if (constexpr_error (input_location, /*constexpr_fundef_p*/true, |
| "invalid return type %qT of %<constexpr%> " |
| "function %q+D", rettype, fun)) |
| explain_non_literal_class (rettype); |
| } |
| } |
| |
| /* C++14 DR 1684 removed this restriction. */ |
| if (cxx_dialect < cxx14 |
| && DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) |
| && !CLASSTYPE_LITERAL_P (DECL_CONTEXT (fun))) |
| { |
| ret = false; |
| if (complain) |
| { |
| auto_diagnostic_group d; |
| if (pedwarn (DECL_SOURCE_LOCATION (fun), OPT_Wpedantic, |
| "enclosing class of %<constexpr%> non-static" |
| " member function %q+#D is not a literal type", |
| fun)) |
| explain_non_literal_class (DECL_CONTEXT (fun)); |
| } |
| } |
| } |
| else if (CLASSTYPE_VBASECLASSES (DECL_CONTEXT (fun))) |
| { |
| ret = false; |
| if (complain) |
| error ("%q#T has virtual base classes", DECL_CONTEXT (fun)); |
| } |
| |
| return ret; |
| } |
| |
| /* Subroutine of build_data_member_initialization. MEMBER is a COMPONENT_REF |
| for a member of an anonymous aggregate, INIT is the initializer for that |
| member, and VEC_OUTER is the vector of constructor elements for the class |
| whose constructor we are processing. Add the initializer to the vector |
| and return true to indicate success. */ |
| |
| static bool |
| build_anon_member_initialization (tree member, tree init, |
| vec<constructor_elt, va_gc> **vec_outer) |
| { |
| /* MEMBER presents the relevant fields from the inside out, but we need |
| to build up the initializer from the outside in so that we can reuse |
| previously built CONSTRUCTORs if this is, say, the second field in an |
| anonymous struct. So we use a vec as a stack. */ |
| auto_vec<tree, 2> fields; |
| do |
| { |
| fields.safe_push (TREE_OPERAND (member, 1)); |
| member = TREE_OPERAND (member, 0); |
| } |
| while (ANON_AGGR_TYPE_P (TREE_TYPE (member)) |
| && TREE_CODE (member) == COMPONENT_REF); |
| |
| /* VEC has the constructor elements vector for the context of FIELD. |
| If FIELD is an anonymous aggregate, we will push inside it. */ |
| vec<constructor_elt, va_gc> **vec = vec_outer; |
| tree field; |
| while (field = fields.pop(), |
| ANON_AGGR_TYPE_P (TREE_TYPE (field))) |
| { |
| tree ctor; |
| /* If there is already an outer constructor entry for the anonymous |
| aggregate FIELD, use it; otherwise, insert one. */ |
| if (vec_safe_is_empty (*vec) |
| || (*vec)->last().index != field) |
| { |
| ctor = build_constructor (TREE_TYPE (field), NULL); |
| CONSTRUCTOR_APPEND_ELT (*vec, field, ctor); |
| } |
| else |
| ctor = (*vec)->last().value; |
| vec = &CONSTRUCTOR_ELTS (ctor); |
| } |
| |
| /* Now we're at the innermost field, the one that isn't an anonymous |
| aggregate. Add its initializer to the CONSTRUCTOR and we're done. */ |
| gcc_assert (fields.is_empty()); |
| CONSTRUCTOR_APPEND_ELT (*vec, field, init); |
| |
| return true; |
| } |
| |
| /* Subroutine of build_constexpr_constructor_member_initializers. |
| The expression tree T represents a data member initialization |
| in a (constexpr) constructor definition. Build a pairing of |
| the data member with its initializer, and prepend that pair |
| to the existing initialization pair INITS. */ |
| |
| static bool |
| build_data_member_initialization (tree t, vec<constructor_elt, va_gc> **vec) |
| { |
| tree member, init; |
| if (TREE_CODE (t) == CLEANUP_POINT_EXPR) |
| t = TREE_OPERAND (t, 0); |
| if (TREE_CODE (t) == EXPR_STMT) |
| t = TREE_OPERAND (t, 0); |
| if (t == error_mark_node) |
| return false; |
| if (TREE_CODE (t) == STATEMENT_LIST) |
| { |
| for (tree stmt : tsi_range (t)) |
| if (! build_data_member_initialization (stmt, vec)) |
| return false; |
| return true; |
| } |
| if (TREE_CODE (t) == CLEANUP_STMT) |
| { |
| /* We can't see a CLEANUP_STMT in a constructor for a literal class, |
| but we can in a constexpr constructor for a non-literal class. Just |
| ignore it; either all the initialization will be constant, in which |
| case the cleanup can't run, or it can't be constexpr. |
| Still recurse into CLEANUP_BODY. */ |
| return build_data_member_initialization (CLEANUP_BODY (t), vec); |
| } |
| if (TREE_CODE (t) == CONVERT_EXPR) |
| t = TREE_OPERAND (t, 0); |
| if (TREE_CODE (t) == INIT_EXPR |
| /* vptr initialization shows up as a MODIFY_EXPR. In C++14 we only |
| use what this function builds for cx_check_missing_mem_inits, and |
| assignment in the ctor body doesn't count. */ |
| || (cxx_dialect < cxx14 && TREE_CODE (t) == MODIFY_EXPR)) |
| { |
| member = TREE_OPERAND (t, 0); |
| init = break_out_target_exprs (TREE_OPERAND (t, 1)); |
| } |
| else if (TREE_CODE (t) == CALL_EXPR) |
| { |
| tree fn = get_callee_fndecl (t); |
| if (!fn || !DECL_CONSTRUCTOR_P (fn)) |
| /* We're only interested in calls to subobject constructors. */ |
| return true; |
| member = CALL_EXPR_ARG (t, 0); |
| /* We don't use build_cplus_new here because it complains about |
| abstract bases. Leaving the call unwrapped means that it has the |
| wrong type, but cxx_eval_constant_expression doesn't care. */ |
| init = break_out_target_exprs (t); |
| } |
| else if (TREE_CODE (t) == BIND_EXPR) |
| return build_data_member_initialization (BIND_EXPR_BODY (t), vec); |
| else |
| /* Don't add anything else to the CONSTRUCTOR. */ |
| return true; |
| if (INDIRECT_REF_P (member)) |
| member = TREE_OPERAND (member, 0); |
| if (TREE_CODE (member) == NOP_EXPR) |
| { |
| tree op = member; |
| STRIP_NOPS (op); |
| if (TREE_CODE (op) == ADDR_EXPR) |
| { |
| gcc_assert (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (TREE_TYPE (op)), |
| TREE_TYPE (TREE_TYPE (member)))); |
| /* Initializing a cv-qualified member; we need to look through |
| the const_cast. */ |
| member = op; |
| } |
| else if (op == current_class_ptr |
| && (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (TREE_TYPE (member)), |
| current_class_type))) |
| /* Delegating constructor. */ |
| member = op; |
| else |
| { |
| /* This is an initializer for an empty base; keep it for now so |
| we can check it in cxx_eval_bare_aggregate. */ |
| gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (member)))); |
| } |
| } |
| if (TREE_CODE (member) == ADDR_EXPR) |
| member = TREE_OPERAND (member, 0); |
| if (TREE_CODE (member) == COMPONENT_REF) |
| { |
| tree aggr = TREE_OPERAND (member, 0); |
| if (TREE_CODE (aggr) == VAR_DECL) |
| /* Initializing a local variable, don't add anything. */ |
| return true; |
| if (TREE_CODE (aggr) != COMPONENT_REF) |
| /* Normal member initialization. */ |
| member = TREE_OPERAND (member, 1); |
| else if (ANON_AGGR_TYPE_P (TREE_TYPE (aggr))) |
| /* Initializing a member of an anonymous union. */ |
| return build_anon_member_initialization (member, init, vec); |
| else |
| /* We're initializing a vtable pointer in a base. Leave it as |
| COMPONENT_REF so we remember the path to get to the vfield. */ |
| gcc_assert (TREE_TYPE (member) == vtbl_ptr_type_node); |
| } |
| |
| /* Value-initialization can produce multiple initializers for the |
| same field; use the last one. */ |
| if (!vec_safe_is_empty (*vec) && (*vec)->last().index == member) |
| (*vec)->last().value = init; |
| else |
| CONSTRUCTOR_APPEND_ELT (*vec, member, init); |
| return true; |
| } |
| |
| /* Subroutine of check_constexpr_ctor_body_1 and constexpr_fn_retval. |
| In C++11 mode checks that the TYPE_DECLs in the BIND_EXPR_VARS of a |
| BIND_EXPR conform to 7.1.5/3/4 on typedef and alias declarations. */ |
| |
| static bool |
| check_constexpr_bind_expr_vars (tree t) |
| { |
| gcc_assert (TREE_CODE (t) == BIND_EXPR); |
| |
| for (tree var = BIND_EXPR_VARS (t); var; var = DECL_CHAIN (var)) |
| if (TREE_CODE (var) == TYPE_DECL |
| && DECL_IMPLICIT_TYPEDEF_P (var) |
| && !LAMBDA_TYPE_P (TREE_TYPE (var))) |
| return false; |
| return true; |
| } |
| |
| /* Subroutine of check_constexpr_ctor_body. */ |
| |
| static bool |
| check_constexpr_ctor_body_1 (tree last, tree list) |
| { |
| switch (TREE_CODE (list)) |
| { |
| case DECL_EXPR: |
| if (TREE_CODE (DECL_EXPR_DECL (list)) == USING_DECL |
| || TREE_CODE (DECL_EXPR_DECL (list)) == TYPE_DECL) |
| return true; |
| return false; |
| |
| case CLEANUP_POINT_EXPR: |
| return check_constexpr_ctor_body (last, TREE_OPERAND (list, 0), |
| /*complain=*/false); |
| |
| case BIND_EXPR: |
| if (!check_constexpr_bind_expr_vars (list) |
| || !check_constexpr_ctor_body (last, BIND_EXPR_BODY (list), |
| /*complain=*/false)) |
| return false; |
| return true; |
| |
| case USING_STMT: |
| case STATIC_ASSERT: |
| case DEBUG_BEGIN_STMT: |
| return true; |
| |
| default: |
| return false; |
| } |
| } |
| |
| /* Make sure that there are no statements after LAST in the constructor |
| body represented by LIST. */ |
| |
| bool |
| check_constexpr_ctor_body (tree last, tree list, bool complain) |
| { |
| /* C++14 doesn't require a constexpr ctor to have an empty body. */ |
| if (cxx_dialect >= cxx14) |
| return true; |
| |
| bool ok = true; |
| if (TREE_CODE (list) == STATEMENT_LIST) |
| { |
| tree_stmt_iterator i = tsi_last (list); |
| for (; !tsi_end_p (i); tsi_prev (&i)) |
| { |
| tree t = tsi_stmt (i); |
| if (t == last) |
| break; |
| if (!check_constexpr_ctor_body_1 (last, t)) |
| { |
| ok = false; |
| break; |
| } |
| } |
| } |
| else if (list != last |
| && !check_constexpr_ctor_body_1 (last, list)) |
| ok = false; |
| if (!ok) |
| { |
| if (complain) |
| error ("%<constexpr%> constructor does not have empty body"); |
| DECL_DECLARED_CONSTEXPR_P (current_function_decl) = false; |
| } |
| return ok; |
| } |
| |
| /* V is a vector of constructor elements built up for the base and member |
| initializers of a constructor for TYPE. They need to be in increasing |
| offset order, which they might not be yet if TYPE has a primary base |
| which is not first in the base-clause or a vptr and at least one base |
| all of which are non-primary. */ |
| |
| static vec<constructor_elt, va_gc> * |
| sort_constexpr_mem_initializers (tree type, vec<constructor_elt, va_gc> *v) |
| { |
| tree pri = CLASSTYPE_PRIMARY_BINFO (type); |
| tree field_type; |
| unsigned i; |
| constructor_elt *ce; |
| |
| if (pri) |
| field_type = BINFO_TYPE (pri); |
| else if (TYPE_CONTAINS_VPTR_P (type)) |
| field_type = vtbl_ptr_type_node; |
| else |
| return v; |
| |
| /* Find the element for the primary base or vptr and move it to the |
| beginning of the vec. */ |
| for (i = 0; vec_safe_iterate (v, i, &ce); ++i) |
| if (TREE_TYPE (ce->index) == field_type) |
| break; |
| |
| if (i > 0 && i < vec_safe_length (v)) |
| { |
| vec<constructor_elt, va_gc> &vref = *v; |
| constructor_elt elt = vref[i]; |
| for (; i > 0; --i) |
| vref[i] = vref[i-1]; |
| vref[0] = elt; |
| } |
| |
| return v; |
| } |
| |
| /* Build compile-time evalable representations of member-initializer list |
| for a constexpr constructor. */ |
| |
| static tree |
| build_constexpr_constructor_member_initializers (tree type, tree body) |
| { |
| vec<constructor_elt, va_gc> *vec = NULL; |
| bool ok = true; |
| while (true) |
| switch (TREE_CODE (body)) |
| { |
| case MUST_NOT_THROW_EXPR: |
| case EH_SPEC_BLOCK: |
| body = TREE_OPERAND (body, 0); |
| break; |
| |
| case STATEMENT_LIST: |
| for (tree stmt : tsi_range (body)) |
| { |
| body = stmt; |
| if (TREE_CODE (body) == BIND_EXPR) |
| break; |
| } |
| break; |
| |
| case BIND_EXPR: |
| body = BIND_EXPR_BODY (body); |
| goto found; |
| |
| default: |
| gcc_unreachable (); |
| } |
| found: |
| if (TREE_CODE (body) == TRY_BLOCK) |
| { |
| body = TREE_OPERAND (body, 0); |
| if (TREE_CODE (body) == BIND_EXPR) |
| body = BIND_EXPR_BODY (body); |
| } |
| if (TREE_CODE (body) == CLEANUP_POINT_EXPR) |
| { |
| body = TREE_OPERAND (body, 0); |
| if (TREE_CODE (body) == EXPR_STMT) |
| body = TREE_OPERAND (body, 0); |
| if (TREE_CODE (body) == INIT_EXPR |
| && (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (TREE_OPERAND (body, 0)), |
| current_class_type))) |
| { |
| /* Trivial copy. */ |
| return TREE_OPERAND (body, 1); |
| } |
| ok = build_data_member_initialization (body, &vec); |
| } |
| else if (TREE_CODE (body) == STATEMENT_LIST) |
| { |
| for (tree stmt : tsi_range (body)) |
| { |
| ok = build_data_member_initialization (stmt, &vec); |
| if (!ok) |
| break; |
| } |
| } |
| else if (EXPR_P (body)) |
| ok = build_data_member_initialization (body, &vec); |
| else |
| gcc_assert (errorcount > 0); |
| if (ok) |
| { |
| if (vec_safe_length (vec) > 0) |
| { |
| /* In a delegating constructor, return the target. */ |
| constructor_elt *ce = &(*vec)[0]; |
| if (ce->index == current_class_ptr) |
| { |
| body = ce->value; |
| vec_free (vec); |
| return body; |
| } |
| } |
| vec = sort_constexpr_mem_initializers (type, vec); |
| return build_constructor (type, vec); |
| } |
| else |
| return error_mark_node; |
| } |
| |
| /* We have an expression tree T that represents a call, either CALL_EXPR |
| or AGGR_INIT_EXPR. If the call is lexically to a named function, |
| retrun the _DECL for that function. */ |
| |
| static tree |
| get_function_named_in_call (tree t) |
| { |
| tree fun = cp_get_callee (t); |
| if (fun && TREE_CODE (fun) == ADDR_EXPR |
| && TREE_CODE (TREE_OPERAND (fun, 0)) == FUNCTION_DECL) |
| fun = TREE_OPERAND (fun, 0); |
| return fun; |
| } |
| |
| /* Subroutine of check_constexpr_fundef. BODY is the body of a function |
| declared to be constexpr, or a sub-statement thereof. Returns the |
| return value if suitable, error_mark_node for a statement not allowed in |
| a constexpr function, or NULL_TREE if no return value was found. */ |
| |
| tree |
| constexpr_fn_retval (tree body) |
| { |
| switch (TREE_CODE (body)) |
| { |
| case STATEMENT_LIST: |
| { |
| tree expr = NULL_TREE; |
| for (tree stmt : tsi_range (body)) |
| { |
| tree s = constexpr_fn_retval (stmt); |
| if (s == error_mark_node) |
| return error_mark_node; |
| else if (s == NULL_TREE) |
| /* Keep iterating. */; |
| else if (expr) |
| /* Multiple return statements. */ |
| return error_mark_node; |
| else |
| expr = s; |
| } |
| return expr; |
| } |
| |
| case RETURN_EXPR: |
| return break_out_target_exprs (TREE_OPERAND (body, 0)); |
| |
| case DECL_EXPR: |
| { |
| tree decl = DECL_EXPR_DECL (body); |
| if (TREE_CODE (decl) == USING_DECL |
| /* Accept __func__, __FUNCTION__, and __PRETTY_FUNCTION__. */ |
| || DECL_ARTIFICIAL (decl)) |
| return NULL_TREE; |
| return error_mark_node; |
| } |
| |
| case CLEANUP_POINT_EXPR: |
| return constexpr_fn_retval (TREE_OPERAND (body, 0)); |
| |
| case BIND_EXPR: |
| if (!check_constexpr_bind_expr_vars (body)) |
| return error_mark_node; |
| return constexpr_fn_retval (BIND_EXPR_BODY (body)); |
| |
| case USING_STMT: |
| case DEBUG_BEGIN_STMT: |
| return NULL_TREE; |
| |
| case CALL_EXPR: |
| { |
| tree fun = get_function_named_in_call (body); |
| if (fun != NULL_TREE |
| && fndecl_built_in_p (fun, BUILT_IN_UNREACHABLE)) |
| return NULL_TREE; |
| } |
| /* Fallthru. */ |
| |
| default: |
| return error_mark_node; |
| } |
| } |
| |
| /* Subroutine of check_constexpr_fundef. BODY is the DECL_SAVED_TREE of |
| FUN; do the necessary transformations to turn it into a single expression |
| that we can store in the hash table. */ |
| |
| static tree |
| massage_constexpr_body (tree fun, tree body) |
| { |
| if (DECL_CONSTRUCTOR_P (fun)) |
| body = build_constexpr_constructor_member_initializers |
| (DECL_CONTEXT (fun), body); |
| else if (cxx_dialect < cxx14) |
| { |
| if (TREE_CODE (body) == EH_SPEC_BLOCK) |
| body = EH_SPEC_STMTS (body); |
| if (TREE_CODE (body) == MUST_NOT_THROW_EXPR) |
| body = TREE_OPERAND (body, 0); |
| body = constexpr_fn_retval (body); |
| } |
| return body; |
| } |
| |
| /* CTYPE is a type constructed from BODY. Return true if some |
| bases/fields are uninitialized, and complain if COMPLAIN. */ |
| |
| static bool |
| cx_check_missing_mem_inits (tree ctype, tree body, bool complain) |
| { |
| /* We allow uninitialized bases/fields in C++20. */ |
| if (cxx_dialect >= cxx20) |
| return false; |
| |
| unsigned nelts = 0; |
| |
| if (body) |
| { |
| if (TREE_CODE (body) != CONSTRUCTOR) |
| return false; |
| nelts = CONSTRUCTOR_NELTS (body); |
| } |
| tree field = TYPE_FIELDS (ctype); |
| |
| if (TREE_CODE (ctype) == UNION_TYPE) |
| { |
| if (nelts == 0 && next_aggregate_field (field)) |
| { |
| if (complain) |
| error ("%<constexpr%> constructor for union %qT must " |
| "initialize exactly one non-static data member", ctype); |
| return true; |
| } |
| return false; |
| } |
| |
| /* Iterate over the CONSTRUCTOR, checking any missing fields don't |
| need an explicit initialization. */ |
| bool bad = false; |
| for (unsigned i = 0; i <= nelts; ++i) |
| { |
| tree index = NULL_TREE; |
| if (i < nelts) |
| { |
| index = CONSTRUCTOR_ELT (body, i)->index; |
| /* Skip base and vtable inits. */ |
| if (TREE_CODE (index) != FIELD_DECL |
| || DECL_ARTIFICIAL (index)) |
| continue; |
| } |
| |
| for (; field != index; field = DECL_CHAIN (field)) |
| { |
| tree ftype; |
| if (TREE_CODE (field) != FIELD_DECL) |
| continue; |
| if (DECL_UNNAMED_BIT_FIELD (field)) |
| continue; |
| if (DECL_ARTIFICIAL (field)) |
| continue; |
| if (ANON_AGGR_TYPE_P (TREE_TYPE (field))) |
| { |
| /* Recurse to check the anonymous aggregate member. */ |
| bad |= cx_check_missing_mem_inits |
| (TREE_TYPE (field), NULL_TREE, complain); |
| if (bad && !complain) |
| return true; |
| continue; |
| } |
| ftype = TREE_TYPE (field); |
| if (!ftype || !TYPE_P (ftype) || !COMPLETE_TYPE_P (ftype)) |
| /* A flexible array can't be intialized here, so don't complain |
| that it isn't. */ |
| continue; |
| if (is_empty_field (field)) |
| /* An empty field doesn't need an initializer. */ |
| continue; |
| ftype = strip_array_types (ftype); |
| if (type_has_constexpr_default_constructor (ftype)) |
| { |
| /* It's OK to skip a member with a trivial constexpr ctor. |
| A constexpr ctor that isn't trivial should have been |
| added in by now. */ |
| gcc_checking_assert (!TYPE_HAS_COMPLEX_DFLT (ftype) |
| || errorcount != 0); |
| continue; |
| } |
| if (!complain) |
| return true; |
| auto_diagnostic_group d; |
| error ("member %qD must be initialized by mem-initializer " |
| "in %<constexpr%> constructor", field); |
| inform (DECL_SOURCE_LOCATION (field), "declared here"); |
| bad = true; |
| } |
| if (field == NULL_TREE) |
| break; |
| |
| if (ANON_AGGR_TYPE_P (TREE_TYPE (index))) |
| { |
| /* Check the anonymous aggregate initializer is valid. */ |
| bad |= cx_check_missing_mem_inits |
| (TREE_TYPE (index), CONSTRUCTOR_ELT (body, i)->value, complain); |
| if (bad && !complain) |
| return true; |
| } |
| field = DECL_CHAIN (field); |
| } |
| |
| return bad; |
| } |
| |
| /* We are processing the definition of the constexpr function FUN. |
| Check that its body fulfills the apropriate requirements and |
| enter it in the constexpr function definition table. */ |
| |
| void |
| maybe_save_constexpr_fundef (tree fun) |
| { |
| if (processing_template_decl |
| || cp_function_chain->invalid_constexpr |
| || (DECL_CLONED_FUNCTION_P (fun) && !DECL_DELETING_DESTRUCTOR_P (fun))) |
| return; |
| |
| /* With -fimplicit-constexpr, try to make inlines constexpr. We'll |
| actually set DECL_DECLARED_CONSTEXPR_P below if the checks pass. */ |
| bool implicit = false; |
| if (flag_implicit_constexpr) |
| { |
| if (DECL_DELETING_DESTRUCTOR_P (fun) |
| && decl_implicit_constexpr_p (DECL_CLONED_FUNCTION (fun))) |
| /* Don't inherit implicit constexpr from the non-deleting |
| destructor. */ |
| DECL_DECLARED_CONSTEXPR_P (fun) = false; |
| |
| if (!DECL_DECLARED_CONSTEXPR_P (fun) |
| && DECL_DECLARED_INLINE_P (fun) |
| && !lookup_attribute ("noinline", DECL_ATTRIBUTES (fun))) |
| implicit = true; |
| } |
| |
| if (!DECL_DECLARED_CONSTEXPR_P (fun) && !implicit) |
| return; |
| |
| bool complain = !DECL_GENERATED_P (fun) && !implicit; |
| |
| if (!is_valid_constexpr_fn (fun, complain)) |
| return; |
| |
| tree massaged = massage_constexpr_body (fun, DECL_SAVED_TREE (fun)); |
| if (massaged == NULL_TREE || massaged == error_mark_node) |
| { |
| if (!DECL_CONSTRUCTOR_P (fun) && complain) |
| error ("body of %<constexpr%> function %qD not a return-statement", |
| fun); |
| return; |
| } |
| |
| bool potential = potential_rvalue_constant_expression (massaged); |
| if (!potential && complain) |
| require_potential_rvalue_constant_expression_fncheck (massaged); |
| |
| if (DECL_CONSTRUCTOR_P (fun) && potential |
| && !DECL_DEFAULTED_FN (fun)) |
| { |
| if (cx_check_missing_mem_inits (DECL_CONTEXT (fun), |
| massaged, complain)) |
| potential = false; |
| else if (cxx_dialect > cxx11) |
| { |
| /* What we got from massage_constexpr_body is pretty much just the |
| ctor-initializer, also check the body. */ |
| massaged = DECL_SAVED_TREE (fun); |
| potential = potential_rvalue_constant_expression (massaged); |
| if (!potential && complain) |
| require_potential_rvalue_constant_expression_fncheck (massaged); |
| } |
| } |
| |
| if (!potential && complain |
| /* If -Wno-invalid-constexpr was specified, we haven't complained |
| about non-constant expressions yet. Register the function and |
| complain in explain_invalid_constexpr_fn if the function is |
| called. */ |
| && warn_invalid_constexpr != 0) |
| return; |
| |
| if (implicit) |
| { |
| if (potential) |
| { |
| DECL_DECLARED_CONSTEXPR_P (fun) = true; |
| DECL_LANG_SPECIFIC (fun)->u.fn.implicit_constexpr = true; |
| if (DECL_CONSTRUCTOR_P (fun)) |
| TYPE_HAS_CONSTEXPR_CTOR (DECL_CONTEXT (fun)) = true; |
| } |
| else |
| /* Don't bother keeping the pre-generic body of unsuitable functions |
| not explicitly declared constexpr. */ |
| return; |
| } |
| |
| constexpr_fundef entry = {fun, NULL_TREE, NULL_TREE, NULL_TREE}; |
| bool clear_ctx = false; |
| if (DECL_RESULT (fun) && DECL_CONTEXT (DECL_RESULT (fun)) == NULL_TREE) |
| { |
| clear_ctx = true; |
| DECL_CONTEXT (DECL_RESULT (fun)) = fun; |
| } |
| tree saved_fn = current_function_decl; |
| current_function_decl = fun; |
| entry.body = copy_fn (entry.decl, entry.parms, entry.result); |
| current_function_decl = saved_fn; |
| if (clear_ctx) |
| DECL_CONTEXT (DECL_RESULT (entry.decl)) = NULL_TREE; |
| if (!potential) |
| /* For a template instantiation, we want to remember the pre-generic body |
| for explain_invalid_constexpr_fn, but do tell cxx_eval_call_expression |
| that it doesn't need to bother trying to expand the function. */ |
| entry.result = error_mark_node; |
| |
| register_constexpr_fundef (entry); |
| } |
| |
| /* BODY is a validated and massaged definition of a constexpr |
| function. Register it in the hash table. */ |
| |
| void |
| register_constexpr_fundef (const constexpr_fundef &value) |
| { |
| /* Create the constexpr function table if necessary. */ |
| if (constexpr_fundef_table == NULL) |
| constexpr_fundef_table |
| = hash_table<constexpr_fundef_hasher>::create_ggc (101); |
| |
| constexpr_fundef **slot = constexpr_fundef_table->find_slot |
| (const_cast<constexpr_fundef *> (&value), INSERT); |
| |
| gcc_assert (*slot == NULL); |
| *slot = ggc_alloc<constexpr_fundef> (); |
| **slot = value; |
| } |
| |
| /* FUN is a non-constexpr (or, with -Wno-invalid-constexpr, a constexpr |
| function called in a context that requires a constant expression). |
| If it comes from a constexpr template, explain why the instantiation |
| isn't constexpr. Otherwise, explain why the function cannot be used |
| in a constexpr context. */ |
| |
| void |
| explain_invalid_constexpr_fn (tree fun) |
| { |
| static hash_set<tree> *diagnosed; |
| tree body; |
| /* In C++23, a function marked 'constexpr' may not actually be a constant |
| expression. We haven't diagnosed the problem yet: -Winvalid-constexpr |
| wasn't enabled. The function was called, so diagnose why it cannot be |
| used in a constant expression. */ |
| if (warn_invalid_constexpr == 0 && DECL_DECLARED_CONSTEXPR_P (fun)) |
| /* Go on. */; |
| /* Only diagnose defaulted functions, lambdas, or instantiations. */ |
| else if (!DECL_DEFAULTED_FN (fun) |
| && !LAMBDA_TYPE_P (CP_DECL_CONTEXT (fun)) |
| && !is_instantiation_of_constexpr (fun)) |
| { |
| inform (DECL_SOURCE_LOCATION (fun), "%qD declared here", fun); |
| return; |
| } |
| if (diagnosed == NULL) |
| diagnosed = new hash_set<tree>; |
| if (diagnosed->add (fun)) |
| /* Already explained. */ |
| return; |
| |
| iloc_sentinel ils = input_location; |
| if (!lambda_static_thunk_p (fun)) |
| { |
| /* Diagnostics should completely ignore the static thunk, so leave |
| input_location set to our caller's location. */ |
| input_location = DECL_SOURCE_LOCATION (fun); |
| inform (input_location, |
| "%qD is not usable as a %<constexpr%> function because:", fun); |
| } |
| /* First check the declaration. */ |
| if (is_valid_constexpr_fn (fun, true)) |
| { |
| /* Then if it's OK, the body. */ |
| if (!DECL_DECLARED_CONSTEXPR_P (fun) |
| && DECL_DEFAULTED_FN (fun)) |
| explain_implicit_non_constexpr (fun); |
| else |
| { |
| if (constexpr_fundef *fd = retrieve_constexpr_fundef (fun)) |
| body = fd->body; |
| else |
| body = DECL_SAVED_TREE (fun); |
| body = massage_constexpr_body (fun, body); |
| require_potential_rvalue_constant_expression (body); |
| if (DECL_CONSTRUCTOR_P (fun)) |
| cx_check_missing_mem_inits (DECL_CONTEXT (fun), body, true); |
| } |
| } |
| } |
| |
| /* Objects of this type represent calls to constexpr functions |
| along with the bindings of parameters to their arguments, for |
| the purpose of compile time evaluation. */ |
| |
| struct GTY((for_user)) constexpr_call { |
| /* Description of the constexpr function definition. */ |
| constexpr_fundef *fundef; |
| /* Parameter bindings environment. A TREE_VEC of arguments. */ |
| tree bindings; |
| /* Result of the call. |
| NULL means the call is being evaluated. |
| error_mark_node means that the evaluation was erroneous; |
| otherwise, the actuall value of the call. */ |
| tree result; |
| /* The hash of this call; we remember it here to avoid having to |
| recalculate it when expanding the hash table. */ |
| hashval_t hash; |
| /* Whether __builtin_is_constant_evaluated() should evaluate to true. */ |
| bool manifestly_const_eval; |
| }; |
| |
| struct constexpr_call_hasher : ggc_ptr_hash<constexpr_call> |
| { |
| static hashval_t hash (constexpr_call *); |
| static bool equal (constexpr_call *, constexpr_call *); |
| }; |
| |
| enum constexpr_switch_state { |
| /* Used when processing a switch for the first time by cxx_eval_switch_expr |
| and default: label for that switch has not been seen yet. */ |
| css_default_not_seen, |
| /* Used when processing a switch for the first time by cxx_eval_switch_expr |
| and default: label for that switch has been seen already. */ |
| css_default_seen, |
| /* Used when processing a switch for the second time by |
| cxx_eval_switch_expr, where default: label should match. */ |
| css_default_processing |
| }; |
| |
| /* The constexpr expansion context part which needs one instance per |
| cxx_eval_outermost_constant_expr invocation. VALUES is a map of values of |
| variables initialized within the expression. */ |
| |
| class constexpr_global_ctx { |
| /* Values for any temporaries or local variables within the |
| constant-expression. */ |
| hash_map<tree,tree> values; |
| public: |
| /* Number of cxx_eval_constant_expression calls (except skipped ones, |
| on simple constants or location wrappers) encountered during current |
| cxx_eval_outermost_constant_expr call. */ |
| HOST_WIDE_INT constexpr_ops_count; |
| /* Heap VAR_DECLs created during the evaluation of the outermost constant |
| expression. */ |
| auto_vec<tree, 16> heap_vars; |
| /* Cleanups that need to be evaluated at the end of CLEANUP_POINT_EXPR. */ |
| vec<tree> *cleanups; |
| /* If non-null, only allow modification of existing values of the variables |
| in this set. Set by modifiable_tracker, below. */ |
| hash_set<tree> *modifiable; |
| /* Number of heap VAR_DECL deallocations. */ |
| unsigned heap_dealloc_count; |
| /* Constructor. */ |
| constexpr_global_ctx () |
| : constexpr_ops_count (0), cleanups (NULL), modifiable (nullptr), |
| heap_dealloc_count (0) {} |
| |
| tree get_value (tree t) |
| { |
| if (tree *p = values.get (t)) |
| return *p; |
| return NULL_TREE; |
| } |
| tree *get_value_ptr (tree t) |
| { |
| if (modifiable && !modifiable->contains (t)) |
| return nullptr; |
| return values.get (t); |
| } |
| void put_value (tree t, tree v) |
| { |
| bool already_in_map = values.put (t, v); |
| if (!already_in_map && modifiable) |
| modifiable->add (t); |
| } |
| void remove_value (tree t) { values.remove (t); } |
| }; |
| |
| /* Helper class for constexpr_global_ctx. In some cases we want to avoid |
| side-effects from evaluation of a particular subexpression of a |
| constant-expression. In such cases we use modifiable_tracker to prevent |
| modification of variables created outside of that subexpression. |
| |
| ??? We could change the hash_set to a hash_map, allow and track external |
| modifications, and roll them back in the destructor. It's not clear to me |
| that this would be worthwhile. */ |
| |
| class modifiable_tracker |
| { |
| hash_set<tree> set; |
| constexpr_global_ctx *global; |
| public: |
| modifiable_tracker (constexpr_global_ctx *g): global(g) |
| { |
| global->modifiable = &set; |
| } |
| ~modifiable_tracker () |
| { |
| for (tree t: set) |
| global->remove_value (t); |
| global->modifiable = nullptr; |
| } |
| }; |
| |
| /* The constexpr expansion context. CALL is the current function |
| expansion, CTOR is the current aggregate initializer, OBJECT is the |
| object being initialized by CTOR, either a VAR_DECL or a _REF. */ |
| |
| struct constexpr_ctx { |
| /* The part of the context that needs to be unique to the whole |
| cxx_eval_outermost_constant_expr invocation. */ |
| constexpr_global_ctx *global; |
| /* The innermost call we're evaluating. */ |
| constexpr_call *call; |
| /* SAVE_EXPRs and TARGET_EXPR_SLOT vars of TARGET_EXPRs that we've seen |
| within the current LOOP_EXPR. NULL if we aren't inside a loop. */ |
| vec<tree> *save_exprs; |
| /* The CONSTRUCTOR we're currently building up for an aggregate |
| initializer. */ |
| tree ctor; |
| /* The object we're building the CONSTRUCTOR for. */ |
| tree object; |
| /* If inside SWITCH_EXPR. */ |
| constexpr_switch_state *css_state; |
| /* The aggregate initialization context inside which this one is nested. This |
| is used by lookup_placeholder to resolve PLACEHOLDER_EXPRs. */ |
| const constexpr_ctx *parent; |
| |
| /* Whether we should error on a non-constant expression or fail quietly. |
| This flag needs to be here, but some of the others could move to global |
| if they get larger than a word. */ |
| bool quiet; |
| /* Whether we are strictly conforming to constant expression rules or |
| trying harder to get a constant value. */ |
| bool strict; |
| /* Whether __builtin_is_constant_evaluated () should be true. */ |
| bool manifestly_const_eval; |
| }; |
| |
| /* This internal flag controls whether we should avoid doing anything during |
| constexpr evaluation that would cause extra DECL_UID generation, such as |
| template instantiation and function body copying. */ |
| |
| static bool uid_sensitive_constexpr_evaluation_value; |
| |
| /* An internal counter that keeps track of the number of times |
| uid_sensitive_constexpr_evaluation_p returned true. */ |
| |
| static unsigned uid_sensitive_constexpr_evaluation_true_counter; |
| |
| /* The accessor for uid_sensitive_constexpr_evaluation_value which also |
| increments the corresponding counter. */ |
| |
| static bool |
| uid_sensitive_constexpr_evaluation_p () |
| { |
| if (uid_sensitive_constexpr_evaluation_value) |
| { |
| ++uid_sensitive_constexpr_evaluation_true_counter; |
| return true; |
| } |
| else |
| return false; |
| } |
| |
| /* The default constructor for uid_sensitive_constexpr_evaluation_sentinel |
| enables the internal flag for uid_sensitive_constexpr_evaluation_p |
| during the lifetime of the sentinel object. Upon its destruction, the |
| previous value of uid_sensitive_constexpr_evaluation_p is restored. */ |
| |
| uid_sensitive_constexpr_evaluation_sentinel |
| ::uid_sensitive_constexpr_evaluation_sentinel () |
| : ovr (uid_sensitive_constexpr_evaluation_value, true) |
| { |
| } |
| |
| /* The default constructor for uid_sensitive_constexpr_evaluation_checker |
| records the current number of times that uid_sensitive_constexpr_evaluation_p |
| has been called and returned true. */ |
| |
| uid_sensitive_constexpr_evaluation_checker |
| ::uid_sensitive_constexpr_evaluation_checker () |
| : saved_counter (uid_sensitive_constexpr_evaluation_true_counter) |
| { |
| } |
| |
| /* Returns true iff uid_sensitive_constexpr_evaluation_p is true, and |
| some constexpr evaluation was restricted due to u_s_c_e_p being called |
| and returning true during the lifetime of this checker object. */ |
| |
| bool |
| uid_sensitive_constexpr_evaluation_checker::evaluation_restricted_p () const |
| { |
| return (uid_sensitive_constexpr_evaluation_value |
| && saved_counter != uid_sensitive_constexpr_evaluation_true_counter); |
| } |
| |
| |
| /* A table of all constexpr calls that have been evaluated by the |
| compiler in this translation unit. */ |
| |
| static GTY (()) hash_table<constexpr_call_hasher> *constexpr_call_table; |
| |
| /* Compute a hash value for a constexpr call representation. */ |
| |
| inline hashval_t |
| constexpr_call_hasher::hash (constexpr_call *info) |
| { |
| return info->hash; |
| } |
| |
| /* Return true if the objects pointed to by P and Q represent calls |
| to the same constexpr function with the same arguments. |
| Otherwise, return false. */ |
| |
| bool |
| constexpr_call_hasher::equal (constexpr_call *lhs, constexpr_call *rhs) |
| { |
| if (lhs == rhs) |
| return true; |
| if (lhs->hash != rhs->hash) |
| return false; |
| if (lhs->manifestly_const_eval != rhs->manifestly_const_eval) |
| return false; |
| if (!constexpr_fundef_hasher::equal (lhs->fundef, rhs->fundef)) |
| return false; |
| return cp_tree_equal (lhs->bindings, rhs->bindings); |
| } |
| |
| /* Initialize the constexpr call table, if needed. */ |
| |
| static void |
| maybe_initialize_constexpr_call_table (void) |
| { |
| if (constexpr_call_table == NULL) |
| constexpr_call_table = hash_table<constexpr_call_hasher>::create_ggc (101); |
| } |
| |
| /* During constexpr CALL_EXPR evaluation, to avoid issues with sharing when |
| a function happens to get called recursively, we unshare the callee |
| function's body and evaluate this unshared copy instead of evaluating the |
| original body. |
| |
| FUNDEF_COPIES_TABLE is a per-function freelist of these unshared function |
| copies. The underlying data structure of FUNDEF_COPIES_TABLE is a hash_map |
| that's keyed off of the original FUNCTION_DECL and whose value is a |
| TREE_LIST of this function's unused copies awaiting reuse. |
| |
| This is not GC-deletable to avoid GC affecting UID generation. */ |
| |
| static GTY(()) decl_tree_map *fundef_copies_table; |
| |
| /* Reuse a copy or create a new unshared copy of the function FUN. |
| Return this copy. We use a TREE_LIST whose PURPOSE is body, VALUE |
| is parms, TYPE is result. */ |
| |
| static tree |
| get_fundef_copy (constexpr_fundef *fundef) |
| { |
| tree copy; |
| bool existed; |
| tree *slot = &(hash_map_safe_get_or_insert<hm_ggc> |
| (fundef_copies_table, fundef->decl, &existed, 127)); |
| |
| if (!existed) |
| { |
| /* There is no cached function available, or in use. We can use |
| the function directly. That the slot is now created records |
| that this function is now in use. */ |
| copy = build_tree_list (fundef->body, fundef->parms); |
| TREE_TYPE (copy) = fundef->result; |
| } |
| else if (*slot == NULL_TREE) |
| { |
| if (uid_sensitive_constexpr_evaluation_p ()) |
| return NULL_TREE; |
| |
| /* We've already used the function itself, so make a copy. */ |
| copy = build_tree_list (NULL, NULL); |
| tree saved_body = DECL_SAVED_TREE (fundef->decl); |
| tree saved_parms = DECL_ARGUMENTS (fundef->decl); |
| tree saved_result = DECL_RESULT (fundef->decl); |
| tree saved_fn = current_function_decl; |
| DECL_SAVED_TREE (fundef->decl) = fundef->body; |
| DECL_ARGUMENTS (fundef->decl) = fundef->parms; |
| DECL_RESULT (fundef->decl) = fundef->result; |
| current_function_decl = fundef->decl; |
| TREE_PURPOSE (copy) = copy_fn (fundef->decl, TREE_VALUE (copy), |
| TREE_TYPE (copy)); |
| current_function_decl = saved_fn; |
| DECL_RESULT (fundef->decl) = saved_result; |
| DECL_ARGUMENTS (fundef->decl) = saved_parms; |
| DECL_SAVED_TREE (fundef->decl) = saved_body; |
| } |
| else |
| { |
| /* We have a cached function available. */ |
| copy = *slot; |
| *slot = TREE_CHAIN (copy); |
| } |
| |
| return copy; |
| } |
| |
| /* Save the copy COPY of function FUN for later reuse by |
| get_fundef_copy(). By construction, there will always be an entry |
| to find. */ |
| |
| static void |
| save_fundef_copy (tree fun, tree copy) |
| { |
| tree *slot = fundef_copies_table->get (fun); |
| TREE_CHAIN (copy) = *slot; |
| *slot = copy; |
| } |
| |
| /* Whether our evaluation wants a prvalue (e.g. CONSTRUCTOR or _CST), |
| a glvalue (e.g. VAR_DECL or _REF), or nothing. */ |
| |
| enum value_cat { |
| vc_prvalue = 0, |
| vc_glvalue = 1, |
| vc_discard = 2 |
| }; |
| |
| static tree cxx_eval_constant_expression (const constexpr_ctx *, tree, |
| value_cat, bool *, bool *, tree * = NULL); |
| static tree cxx_fold_indirect_ref (const constexpr_ctx *, location_t, tree, tree, |
| bool * = NULL); |
| static tree find_heap_var_refs (tree *, int *, void *); |
| |
| /* Attempt to evaluate T which represents a call to a builtin function. |
| We assume here that all builtin functions evaluate to scalar types |
| represented by _CST nodes. */ |
| |
| static tree |
| cxx_eval_builtin_function_call (const constexpr_ctx *ctx, tree t, tree fun, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| const int nargs = call_expr_nargs (t); |
| tree *args = (tree *) alloca (nargs * sizeof (tree)); |
| tree new_call; |
| int i; |
| |
| /* Don't fold __builtin_constant_p within a constexpr function. */ |
| bool bi_const_p = DECL_IS_BUILTIN_CONSTANT_P (fun); |
| |
| /* If we aren't requiring a constant expression, defer __builtin_constant_p |
| in a constexpr function until we have values for the parameters. */ |
| if (bi_const_p |
| && !ctx->manifestly_const_eval |
| && current_function_decl |
| && DECL_DECLARED_CONSTEXPR_P (current_function_decl)) |
| { |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* For __builtin_is_constant_evaluated, defer it if not |
| ctx->manifestly_const_eval (as sometimes we try to constant evaluate |
| without manifestly_const_eval even expressions or parts thereof which |
| will later be manifestly const_eval evaluated), otherwise fold it to |
| true. */ |
| if (fndecl_built_in_p (fun, CP_BUILT_IN_IS_CONSTANT_EVALUATED, |
| BUILT_IN_FRONTEND)) |
| { |
| if (!ctx->manifestly_const_eval) |
| { |
| *non_constant_p = true; |
| return t; |
| } |
| return boolean_true_node; |
| } |
| |
| if (fndecl_built_in_p (fun, CP_BUILT_IN_SOURCE_LOCATION, BUILT_IN_FRONTEND)) |
| { |
| temp_override<tree> ovr (current_function_decl); |
| if (ctx->call && ctx->call->fundef) |
| current_function_decl = ctx->call->fundef->decl; |
| return fold_builtin_source_location (t); |
| } |
| |
| int strops = 0; |
| int strret = 0; |
| if (fndecl_built_in_p (fun, BUILT_IN_NORMAL)) |
| switch (DECL_FUNCTION_CODE (fun)) |
| { |
| case BUILT_IN_STRLEN: |
| case BUILT_IN_STRNLEN: |
| strops = 1; |
| break; |
| case BUILT_IN_MEMCHR: |
| case BUILT_IN_STRCHR: |
| case BUILT_IN_STRRCHR: |
| strops = 1; |
| strret = 1; |
| break; |
| case BUILT_IN_MEMCMP: |
| case BUILT_IN_STRCMP: |
| strops = 2; |
| break; |
| case BUILT_IN_STRSTR: |
| strops = 2; |
| strret = 1; |
| break; |
| case BUILT_IN_ASAN_POINTER_COMPARE: |
| case BUILT_IN_ASAN_POINTER_SUBTRACT: |
| /* These builtins shall be ignored during constant expression |
| evaluation. */ |
| return void_node; |
| case BUILT_IN_UNREACHABLE: |
| case BUILT_IN_TRAP: |
| if (!*non_constant_p && !ctx->quiet) |
| { |
| /* Do not allow__builtin_unreachable in constexpr function. |
| The __builtin_unreachable call with BUILTINS_LOCATION |
| comes from cp_maybe_instrument_return. */ |
| if (EXPR_LOCATION (t) == BUILTINS_LOCATION) |
| error ("%<constexpr%> call flows off the end of the function"); |
| else |
| error ("%q+E is not a constant expression", t); |
| } |
| *non_constant_p = true; |
| return t; |
| default: |
| break; |
| } |
| |
| /* Be permissive for arguments to built-ins; __builtin_constant_p should |
| return constant false for a non-constant argument. */ |
| constexpr_ctx new_ctx = *ctx; |
| new_ctx.quiet = true; |
| for (i = 0; i < nargs; ++i) |
| { |
| tree arg = CALL_EXPR_ARG (t, i); |
| tree oarg = arg; |
| |
| /* To handle string built-ins we need to pass ADDR_EXPR<STRING_CST> since |
| expand_builtin doesn't know how to look in the values table. */ |
| bool strop = i < strops; |
| if (strop) |
| { |
| STRIP_NOPS (arg); |
| if (TREE_CODE (arg) == ADDR_EXPR) |
| arg = TREE_OPERAND (arg, 0); |
| else |
| strop = false; |
| } |
| |
| /* If builtin_valid_in_constant_expr_p is true, |
| potential_constant_expression_1 has not recursed into the arguments |
| of the builtin, verify it here. */ |
| if (!builtin_valid_in_constant_expr_p (fun) |
| || potential_constant_expression (arg)) |
| { |
| bool dummy1 = false, dummy2 = false; |
| arg = cxx_eval_constant_expression (&new_ctx, arg, vc_prvalue, |
| &dummy1, &dummy2); |
| } |
| |
| if (bi_const_p) |
| /* For __builtin_constant_p, fold all expressions with constant values |
| even if they aren't C++ constant-expressions. */ |
| arg = cp_fold_rvalue (arg); |
| else if (strop) |
| { |
| if (TREE_CODE (arg) == CONSTRUCTOR) |
| arg = braced_lists_to_strings (TREE_TYPE (arg), arg); |
| if (TREE_CODE (arg) == STRING_CST) |
| arg = build_address (arg); |
| else |
| arg = oarg; |
| } |
| |
| args[i] = arg; |
| } |
| |
| bool save_ffbcp = force_folding_builtin_constant_p; |
| force_folding_builtin_constant_p |= ctx->manifestly_const_eval; |
| tree save_cur_fn = current_function_decl; |
| /* Return name of ctx->call->fundef->decl for __builtin_FUNCTION (). */ |
| if (fndecl_built_in_p (fun, BUILT_IN_FUNCTION) |
| && ctx->call |
| && ctx->call->fundef) |
| current_function_decl = ctx->call->fundef->decl; |
| if (fndecl_built_in_p (fun, |
| CP_BUILT_IN_IS_POINTER_INTERCONVERTIBLE_WITH_CLASS, |
| BUILT_IN_FRONTEND)) |
| { |
| location_t loc = EXPR_LOCATION (t); |
| if (nargs >= 1) |
| VERIFY_CONSTANT (args[0]); |
| new_call |
| = fold_builtin_is_pointer_inverconvertible_with_class (loc, nargs, |
| args); |
| } |
| else if (fndecl_built_in_p (fun, |
| CP_BUILT_IN_IS_CORRESPONDING_MEMBER, |
| BUILT_IN_FRONTEND)) |
| { |
| location_t loc = EXPR_LOCATION (t); |
| if (nargs >= 2) |
| { |
| VERIFY_CONSTANT (args[0]); |
| VERIFY_CONSTANT (args[1]); |
| } |
| new_call = fold_builtin_is_corresponding_member (loc, nargs, args); |
| } |
| else |
| new_call = fold_builtin_call_array (EXPR_LOCATION (t), TREE_TYPE (t), |
| CALL_EXPR_FN (t), nargs, args); |
| current_function_decl = save_cur_fn; |
| force_folding_builtin_constant_p = save_ffbcp; |
| if (new_call == NULL) |
| { |
| if (!*non_constant_p && !ctx->quiet) |
| { |
| new_call = build_call_array_loc (EXPR_LOCATION (t), TREE_TYPE (t), |
| CALL_EXPR_FN (t), nargs, args); |
| error ("%q+E is not a constant expression", new_call); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| |
| if (!potential_constant_expression (new_call)) |
| { |
| if (!*non_constant_p && !ctx->quiet) |
| error ("%q+E is not a constant expression", new_call); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| if (strret) |
| { |
| /* memchr returns a pointer into the first argument, but we replaced the |
| argument above with a STRING_CST; put it back it now. */ |
| tree op = CALL_EXPR_ARG (t, strret-1); |
| STRIP_NOPS (new_call); |
| if (TREE_CODE (new_call) == POINTER_PLUS_EXPR) |
| TREE_OPERAND (new_call, 0) = op; |
| else if (TREE_CODE (new_call) == ADDR_EXPR) |
| new_call = op; |
| } |
| |
| return cxx_eval_constant_expression (&new_ctx, new_call, lval, |
| non_constant_p, overflow_p); |
| } |
| |
| /* TEMP is the constant value of a temporary object of type TYPE. Adjust |
| the type of the value to match. */ |
| |
| static tree |
| adjust_temp_type (tree type, tree temp) |
| { |
| if (same_type_p (TREE_TYPE (temp), type)) |
| return temp; |
| /* Avoid wrapping an aggregate value in a NOP_EXPR. */ |
| if (TREE_CODE (temp) == CONSTRUCTOR) |
| { |
| /* build_constructor wouldn't retain various CONSTRUCTOR flags. */ |
| tree t = copy_node (temp); |
| TREE_TYPE (t) = type; |
| return t; |
| } |
| if (TREE_CODE (temp) == EMPTY_CLASS_EXPR) |
| return build0 (EMPTY_CLASS_EXPR, type); |
| gcc_assert (scalarish_type_p (type)); |
| /* Now we know we're dealing with a scalar, and a prvalue of non-class |
| type is cv-unqualified. */ |
| return cp_fold_convert (cv_unqualified (type), temp); |
| } |
| |
| /* If T is a CONSTRUCTOR, return an unshared copy of T and any |
| sub-CONSTRUCTORs. Otherwise return T. |
| |
| We use this whenever we initialize an object as a whole, whether it's a |
| parameter, a local variable, or a subobject, so that subsequent |
| modifications don't affect other places where it was used. */ |
| |
| tree |
| unshare_constructor (tree t MEM_STAT_DECL) |
| { |
| if (!t || TREE_CODE (t) != CONSTRUCTOR) |
| return t; |
| auto_vec <tree*, 4> ptrs; |
| ptrs.safe_push (&t); |
| while (!ptrs.is_empty ()) |
| { |
| tree *p = ptrs.pop (); |
| tree n = copy_node (*p PASS_MEM_STAT); |
| CONSTRUCTOR_ELTS (n) = vec_safe_copy (CONSTRUCTOR_ELTS (*p) PASS_MEM_STAT); |
| *p = n; |
| vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (n); |
| constructor_elt *ce; |
| for (HOST_WIDE_INT i = 0; vec_safe_iterate (v, i, &ce); ++i) |
| if (ce->value && TREE_CODE (ce->value) == CONSTRUCTOR) |
| ptrs.safe_push (&ce->value); |
| } |
| return t; |
| } |
| |
| /* If T is a CONSTRUCTOR, ggc_free T and any sub-CONSTRUCTORs. */ |
| |
| static void |
| free_constructor (tree t) |
| { |
| if (!t || TREE_CODE (t) != CONSTRUCTOR) |
| return; |
| releasing_vec ctors; |
| vec_safe_push (ctors, t); |
| while (!ctors->is_empty ()) |
| { |
| tree c = ctors->pop (); |
| if (vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (c)) |
| { |
| constructor_elt *ce; |
| for (HOST_WIDE_INT i = 0; vec_safe_iterate (elts, i, &ce); ++i) |
| if (TREE_CODE (ce->value) == CONSTRUCTOR) |
| vec_safe_push (ctors, ce->value); |
| ggc_free (elts); |
| } |
| ggc_free (c); |
| } |
| } |
| |
| /* Helper function of cxx_bind_parameters_in_call. Return non-NULL |
| if *TP is address of a static variable (or part of it) currently being |
| constructed or of a heap artificial variable. */ |
| |
| static tree |
| addr_of_non_const_var (tree *tp, int *walk_subtrees, void *data) |
| { |
| if (TREE_CODE (*tp) == ADDR_EXPR) |
| if (tree var = get_base_address (TREE_OPERAND (*tp, 0))) |
| if (VAR_P (var) && TREE_STATIC (var)) |
| { |
| if (DECL_NAME (var) == heap_uninit_identifier |
| || DECL_NAME (var) == heap_identifier |
| || DECL_NAME (var) == heap_vec_uninit_identifier |
| || DECL_NAME (var) == heap_vec_identifier) |
| return var; |
| |
| constexpr_global_ctx *global = (constexpr_global_ctx *) data; |
| if (global->get_value (var)) |
| return var; |
| } |
| if (TYPE_P (*tp)) |
| *walk_subtrees = false; |
| return NULL_TREE; |
| } |
| |
| /* Subroutine of cxx_eval_call_expression. |
| We are processing a call expression (either CALL_EXPR or |
| AGGR_INIT_EXPR) in the context of CTX. Evaluate |
| all arguments and bind their values to correspondings |
| parameters, making up the NEW_CALL context. */ |
| |
| static tree |
| cxx_bind_parameters_in_call (const constexpr_ctx *ctx, tree t, tree fun, |
| bool *non_constant_p, bool *overflow_p, |
| bool *non_constant_args) |
| { |
| const int nargs = call_expr_nargs (t); |
| tree parms = DECL_ARGUMENTS (fun); |
| int i; |
| /* We don't record ellipsis args below. */ |
| int nparms = list_length (parms); |
| int nbinds = nargs < nparms ? nargs : nparms; |
| tree binds = make_tree_vec (nbinds); |
| for (i = 0; i < nargs; ++i) |
| { |
| tree x, arg; |
| tree type = parms ? TREE_TYPE (parms) : void_type_node; |
| if (parms && DECL_BY_REFERENCE (parms)) |
| type = TREE_TYPE (type); |
| x = get_nth_callarg (t, i); |
| /* For member function, the first argument is a pointer to the implied |
| object. For a constructor, it might still be a dummy object, in |
| which case we get the real argument from ctx. */ |
| if (i == 0 && DECL_CONSTRUCTOR_P (fun) |
| && is_dummy_object (x)) |
| { |
| x = ctx->object; |
| x = build_address (x); |
| } |
| if (TREE_ADDRESSABLE (type)) |
| /* Undo convert_for_arg_passing work here. */ |
| x = convert_from_reference (x); |
| /* Normally we would strip a TARGET_EXPR in an initialization context |
| such as this, but here we do the elision differently: we keep the |
| TARGET_EXPR, and use its CONSTRUCTOR as the value of the parm. */ |
| arg = cxx_eval_constant_expression (ctx, x, vc_prvalue, |
| non_constant_p, overflow_p); |
| /* Don't VERIFY_CONSTANT here. */ |
| if (*non_constant_p && ctx->quiet) |
| break; |
| /* Just discard ellipsis args after checking their constantitude. */ |
| if (!parms) |
| continue; |
| |
| if (!*non_constant_p) |
| { |
| /* Make sure the binding has the same type as the parm. But |
| only for constant args. */ |
| if (!TYPE_REF_P (type)) |
| arg = adjust_temp_type (type, arg); |
| if (!TREE_CONSTANT (arg)) |
| *non_constant_args = true; |
| else if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type)) |
| /* The destructor needs to see any modifications the callee makes |
| to the argument. */ |
| *non_constant_args = true; |
| /* If arg is or contains address of a heap artificial variable or |
| of a static variable being constructed, avoid caching the |
| function call, as those variables might be modified by the |
| function, or might be modified by the callers in between |
| the cached function and just read by the function. */ |
| else if (!*non_constant_args |
| && cp_walk_tree (&arg, addr_of_non_const_var, ctx->global, |
| NULL)) |
| *non_constant_args = true; |
| |
| /* For virtual calls, adjust the this argument, so that it is |
| the object on which the method is called, rather than |
| one of its bases. */ |
| if (i == 0 && DECL_VIRTUAL_P (fun)) |
| { |
| tree addr = arg; |
| STRIP_NOPS (addr); |
| if (TREE_CODE (addr) == ADDR_EXPR) |
| { |
| tree obj = TREE_OPERAND (addr, 0); |
| while (TREE_CODE (obj) == COMPONENT_REF |
| && DECL_FIELD_IS_BASE (TREE_OPERAND (obj, 1)) |
| && !same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (obj), DECL_CONTEXT (fun))) |
| obj = TREE_OPERAND (obj, 0); |
| if (obj != TREE_OPERAND (addr, 0)) |
| arg = build_fold_addr_expr_with_type (obj, |
| TREE_TYPE (arg)); |
| } |
| } |
| TREE_VEC_ELT (binds, i) = arg; |
| } |
| parms = TREE_CHAIN (parms); |
| } |
| |
| return binds; |
| } |
| |
| /* Variables and functions to manage constexpr call expansion context. |
| These do not need to be marked for PCH or GC. */ |
| |
| /* FIXME remember and print actual constant arguments. */ |
| static vec<tree> call_stack; |
| static int call_stack_tick; |
| static int last_cx_error_tick; |
| |
| static int |
| push_cx_call_context (tree call) |
| { |
| ++call_stack_tick; |
| if (!EXPR_HAS_LOCATION (call)) |
| SET_EXPR_LOCATION (call, input_location); |
| call_stack.safe_push (call); |
| int len = call_stack.length (); |
| if (len > max_constexpr_depth) |
| return false; |
| return len; |
| } |
| |
| static void |
| pop_cx_call_context (void) |
| { |
| ++call_stack_tick; |
| call_stack.pop (); |
| } |
| |
| vec<tree> |
| cx_error_context (void) |
| { |
| vec<tree> r = vNULL; |
| if (call_stack_tick != last_cx_error_tick |
| && !call_stack.is_empty ()) |
| r = call_stack; |
| last_cx_error_tick = call_stack_tick; |
| return r; |
| } |
| |
| /* E is an operand of a failed assertion, fold it either with or without |
| constexpr context. */ |
| |
| static tree |
| fold_operand (tree e, const constexpr_ctx *ctx) |
| { |
| if (ctx) |
| { |
| bool new_non_constant_p = false, new_overflow_p = false; |
| e = cxx_eval_constant_expression (ctx, e, vc_prvalue, |
| &new_non_constant_p, |
| &new_overflow_p); |
| } |
| else |
| e = fold_non_dependent_expr (e, tf_none, /*manifestly_const_eval=*/true); |
| return e; |
| } |
| |
| /* If we have a condition in conjunctive normal form (CNF), find the first |
| failing clause. In other words, given an expression like |
| |
| true && true && false && true && false |
| |
| return the first 'false'. EXPR is the expression. */ |
| |
| static tree |
| find_failing_clause_r (const constexpr_ctx *ctx, tree expr) |
| { |
| if (TREE_CODE (expr) == TRUTH_ANDIF_EXPR) |
| { |
| /* First check the left side... */ |
| tree e = find_failing_clause_r (ctx, TREE_OPERAND (expr, 0)); |
| if (e == NULL_TREE) |
| /* ...if we didn't find a false clause, check the right side. */ |
| e = find_failing_clause_r (ctx, TREE_OPERAND (expr, 1)); |
| return e; |
| } |
| tree e = contextual_conv_bool (expr, tf_none); |
| e = fold_operand (e, ctx); |
| if (integer_zerop (e)) |
| /* This is the failing clause. */ |
| return expr; |
| return NULL_TREE; |
| } |
| |
| /* Wrapper for find_failing_clause_r. */ |
| |
| tree |
| find_failing_clause (const constexpr_ctx *ctx, tree expr) |
| { |
| if (TREE_CODE (expr) == TRUTH_ANDIF_EXPR) |
| if (tree e = find_failing_clause_r (ctx, expr)) |
| expr = e; |
| return expr; |
| } |
| |
| /* Emit additional diagnostics for failing condition BAD. |
| Used by finish_static_assert and IFN_ASSUME constexpr diagnostics. |
| If SHOW_EXPR_P is true, print the condition (because it was |
| instantiation-dependent). */ |
| |
| void |
| diagnose_failing_condition (tree bad, location_t cloc, bool show_expr_p, |
| const constexpr_ctx *ctx /* = nullptr */) |
| { |
| /* Nobody wants to see the artificial (bool) cast. */ |
| bad = tree_strip_nop_conversions (bad); |
| if (TREE_CODE (bad) == CLEANUP_POINT_EXPR) |
| bad = TREE_OPERAND (bad, 0); |
| |
| /* Actually explain the failure if this is a concept check or a |
| requires-expression. */ |
| if (concept_check_p (bad) || TREE_CODE (bad) == REQUIRES_EXPR) |
| diagnose_constraints (cloc, bad, NULL_TREE); |
| else if (COMPARISON_CLASS_P (bad) |
| && ARITHMETIC_TYPE_P (TREE_TYPE (TREE_OPERAND (bad, 0)))) |
| { |
| tree op0 = fold_operand (TREE_OPERAND (bad, 0), ctx); |
| tree op1 = fold_operand (TREE_OPERAND (bad, 1), ctx); |
| tree cond = build2 (TREE_CODE (bad), boolean_type_node, op0, op1); |
| inform (cloc, "the comparison reduces to %qE", cond); |
| } |
| else if (show_expr_p) |
| inform (cloc, "%qE evaluates to false", bad); |
| } |
| |
| /* Process an assert/assume of ORIG_ARG. If it's not supposed to be evaluated, |
| do it without changing the current evaluation state. If it evaluates to |
| false, complain and return false; otherwise, return true. */ |
| |
| static bool |
| cxx_eval_assert (const constexpr_ctx *ctx, tree arg, const char *msg, |
| location_t loc, bool evaluated, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| if (*non_constant_p) |
| return true; |
| |
| tree eval; |
| if (!evaluated) |
| { |
| if (!potential_rvalue_constant_expression (arg)) |
| return true; |
| |
| constexpr_ctx new_ctx = *ctx; |
| new_ctx.quiet = true; |
| bool new_non_constant_p = false, new_overflow_p = false; |
| /* Avoid modification of existing values. */ |
| modifiable_tracker ms (new_ctx.global); |
| eval = cxx_eval_constant_expression (&new_ctx, arg, vc_prvalue, |
| &new_non_constant_p, |
| &new_overflow_p); |
| } |
| else |
| eval = cxx_eval_constant_expression (ctx, arg, vc_prvalue, |
| non_constant_p, |
| overflow_p); |
| if (!*non_constant_p && integer_zerop (eval)) |
| { |
| if (!ctx->quiet) |
| { |
| /* See if we can find which clause was failing |
| (for logical AND). */ |
| tree bad = find_failing_clause (ctx, arg); |
| /* If not, or its location is unusable, fall back to the |
| previous location. */ |
| location_t cloc = cp_expr_loc_or_loc (bad, loc); |
| |
| /* Report the error. */ |
| auto_diagnostic_group d; |
| error_at (cloc, msg); |
| diagnose_failing_condition (bad, cloc, true, ctx); |
| return bad; |
| } |
| *non_constant_p = true; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| /* Evaluate a call T to a GCC internal function when possible and return |
| the evaluated result or, under the control of CTX, give an error, set |
| NON_CONSTANT_P, and return the unevaluated call T otherwise. */ |
| |
| static tree |
| cxx_eval_internal_function (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| enum tree_code opcode = ERROR_MARK; |
| |
| switch (CALL_EXPR_IFN (t)) |
| { |
| case IFN_UBSAN_NULL: |
| case IFN_UBSAN_BOUNDS: |
| case IFN_UBSAN_VPTR: |
| case IFN_FALLTHROUGH: |
| return void_node; |
| |
| case IFN_ASSUME: |
| if (!cxx_eval_assert (ctx, CALL_EXPR_ARG (t, 0), |
| G_("failed %<assume%> attribute assumption"), |
| EXPR_LOCATION (t), /*eval*/false, |
| non_constant_p, overflow_p)) |
| return t; |
| return void_node; |
| |
| case IFN_ADD_OVERFLOW: |
| opcode = PLUS_EXPR; |
| break; |
| case IFN_SUB_OVERFLOW: |
| opcode = MINUS_EXPR; |
| break; |
| case IFN_MUL_OVERFLOW: |
| opcode = MULT_EXPR; |
| break; |
| |
| case IFN_LAUNDER: |
| return cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), |
| vc_prvalue, non_constant_p, |
| overflow_p); |
| |
| case IFN_VEC_CONVERT: |
| { |
| tree arg = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), |
| vc_prvalue, non_constant_p, |
| overflow_p); |
| if (TREE_CODE (arg) == VECTOR_CST) |
| if (tree r = fold_const_call (CFN_VEC_CONVERT, TREE_TYPE (t), arg)) |
| return r; |
| } |
| /* FALLTHRU */ |
| |
| default: |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "call to internal function %qE", t); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* Evaluate constant arguments using OPCODE and return a complex |
| number containing the result and the overflow bit. */ |
| tree arg0 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 0), lval, |
| non_constant_p, overflow_p); |
| tree arg1 = cxx_eval_constant_expression (ctx, CALL_EXPR_ARG (t, 1), lval, |
| non_constant_p, overflow_p); |
| |
| if (TREE_CODE (arg0) == INTEGER_CST && TREE_CODE (arg1) == INTEGER_CST) |
| { |
| location_t loc = cp_expr_loc_or_input_loc (t); |
| tree type = TREE_TYPE (TREE_TYPE (t)); |
| tree result = fold_binary_loc (loc, opcode, type, |
| fold_convert_loc (loc, type, arg0), |
| fold_convert_loc (loc, type, arg1)); |
| tree ovf |
| = build_int_cst (type, arith_overflowed_p (opcode, type, arg0, arg1)); |
| /* Reset TREE_OVERFLOW to avoid warnings for the overflow. */ |
| if (TREE_OVERFLOW (result)) |
| TREE_OVERFLOW (result) = 0; |
| |
| return build_complex (TREE_TYPE (t), result, ovf); |
| } |
| |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* Clean CONSTRUCTOR_NO_CLEARING from CTOR and its sub-aggregates. */ |
| |
| static void |
| clear_no_implicit_zero (tree ctor) |
| { |
| if (CONSTRUCTOR_NO_CLEARING (ctor)) |
| { |
| CONSTRUCTOR_NO_CLEARING (ctor) = false; |
| for (auto &e: CONSTRUCTOR_ELTS (ctor)) |
| if (TREE_CODE (e.value) == CONSTRUCTOR) |
| clear_no_implicit_zero (e.value); |
| } |
| } |
| |
| /* Complain about a const object OBJ being modified in a constant expression. |
| EXPR is the MODIFY_EXPR expression performing the modification. */ |
| |
| static void |
| modifying_const_object_error (tree expr, tree obj) |
| { |
| location_t loc = cp_expr_loc_or_input_loc (expr); |
| auto_diagnostic_group d; |
| error_at (loc, "modifying a const object %qE is not allowed in " |
| "a constant expression", TREE_OPERAND (expr, 0)); |
| inform (location_of (obj), "originally declared %<const%> here"); |
| } |
| |
| /* Return true if FNDECL is a replaceable global allocation function that |
| should be useable during constant expression evaluation. */ |
| |
| static inline bool |
| cxx_replaceable_global_alloc_fn (tree fndecl) |
| { |
| return (cxx_dialect >= cxx20 |
| && IDENTIFIER_NEWDEL_OP_P (DECL_NAME (fndecl)) |
| && CP_DECL_CONTEXT (fndecl) == global_namespace |
| && (DECL_IS_REPLACEABLE_OPERATOR_NEW_P (fndecl) |
| || DECL_IS_OPERATOR_DELETE_P (fndecl))); |
| } |
| |
| /* Return true if FNDECL is a placement new function that should be |
| useable during constant expression evaluation of std::construct_at. */ |
| |
| static inline bool |
| cxx_placement_new_fn (tree fndecl) |
| { |
| if (cxx_dialect >= cxx20 |
| && IDENTIFIER_NEW_OP_P (DECL_NAME (fndecl)) |
| && CP_DECL_CONTEXT (fndecl) == global_namespace |
| && !DECL_IS_REPLACEABLE_OPERATOR_NEW_P (fndecl) |
| && TREE_CODE (TREE_TYPE (fndecl)) == FUNCTION_TYPE) |
| { |
| tree first_arg = TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (fndecl))); |
| if (TREE_VALUE (first_arg) == ptr_type_node |
| && TREE_CHAIN (first_arg) == void_list_node) |
| return true; |
| } |
| return false; |
| } |
| |
| /* Return true if FNDECL is std::construct_at. */ |
| |
| static inline bool |
| is_std_construct_at (tree fndecl) |
| { |
| if (!decl_in_std_namespace_p (fndecl)) |
| return false; |
| |
| tree name = DECL_NAME (fndecl); |
| return name && id_equal (name, "construct_at"); |
| } |
| |
| /* Overload for the above taking constexpr_call*. */ |
| |
| static inline bool |
| is_std_construct_at (const constexpr_call *call) |
| { |
| return (call |
| && call->fundef |
| && is_std_construct_at (call->fundef->decl)); |
| } |
| |
| /* True if CTX is an instance of std::allocator. */ |
| |
| bool |
| is_std_allocator (tree ctx) |
| { |
| if (ctx == NULL_TREE || !CLASS_TYPE_P (ctx) || !TYPE_MAIN_DECL (ctx)) |
| return false; |
| |
| tree decl = TYPE_MAIN_DECL (ctx); |
| tree name = DECL_NAME (decl); |
| if (name == NULL_TREE || !id_equal (name, "allocator")) |
| return false; |
| |
| return decl_in_std_namespace_p (decl); |
| } |
| |
| /* Return true if FNDECL is std::allocator<T>::{,de}allocate. */ |
| |
| static inline bool |
| is_std_allocator_allocate (tree fndecl) |
| { |
| tree name = DECL_NAME (fndecl); |
| if (name == NULL_TREE |
| || !(id_equal (name, "allocate") || id_equal (name, "deallocate"))) |
| return false; |
| |
| return is_std_allocator (DECL_CONTEXT (fndecl)); |
| } |
| |
| /* Overload for the above taking constexpr_call*. */ |
| |
| static inline bool |
| is_std_allocator_allocate (const constexpr_call *call) |
| { |
| return (call |
| && call->fundef |
| && is_std_allocator_allocate (call->fundef->decl)); |
| } |
| |
| /* Return true if FNDECL is __dynamic_cast. */ |
| |
| static inline bool |
| cxx_dynamic_cast_fn_p (tree fndecl) |
| { |
| return (cxx_dialect >= cxx20 |
| && id_equal (DECL_NAME (fndecl), "__dynamic_cast") |
| && CP_DECL_CONTEXT (fndecl) == abi_node); |
| } |
| |
| /* Often, we have an expression in the form of address + offset, e.g. |
| "&_ZTV1A + 16". Extract the object from it, i.e. "_ZTV1A". */ |
| |
| static tree |
| extract_obj_from_addr_offset (tree expr) |
| { |
| if (TREE_CODE (expr) == POINTER_PLUS_EXPR) |
| expr = TREE_OPERAND (expr, 0); |
| STRIP_NOPS (expr); |
| if (TREE_CODE (expr) == ADDR_EXPR) |
| expr = TREE_OPERAND (expr, 0); |
| return expr; |
| } |
| |
| /* Given a PATH like |
| |
| g.D.2181.D.2154.D.2102.D.2093 |
| |
| find a component with type TYPE. Return NULL_TREE if not found, and |
| error_mark_node if the component is not accessible. If STOP is non-null, |
| this function will return NULL_TREE if STOP is found before TYPE. */ |
| |
| static tree |
| get_component_with_type (tree path, tree type, tree stop) |
| { |
| while (true) |
| { |
| if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (path), type)) |
| /* Found it. */ |
| return path; |
| else if (stop |
| && (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (path), |
| stop))) |
| return NULL_TREE; |
| else if (TREE_CODE (path) == COMPONENT_REF |
| && DECL_FIELD_IS_BASE (TREE_OPERAND (path, 1))) |
| { |
| /* We need to check that the component we're accessing is in fact |
| accessible. */ |
| if (TREE_PRIVATE (TREE_OPERAND (path, 1)) |
| || TREE_PROTECTED (TREE_OPERAND (path, 1))) |
| return error_mark_node; |
| path = TREE_OPERAND (path, 0); |
| } |
| else |
| return NULL_TREE; |
| } |
| } |
| |
| /* Evaluate a call to __dynamic_cast (permitted by P1327R1). |
| |
| The declaration of __dynamic_cast is: |
| |
| void* __dynamic_cast (const void* __src_ptr, |
| const __class_type_info* __src_type, |
| const __class_type_info* __dst_type, |
| ptrdiff_t __src2dst); |
| |
| where src2dst has the following possible values |
| |
| >-1: src_type is a unique public non-virtual base of dst_type |
| dst_ptr + src2dst == src_ptr |
| -1: unspecified relationship |
| -2: src_type is not a public base of dst_type |
| -3: src_type is a multiple public non-virtual base of dst_type |
| |
| Since literal types can't have virtual bases, we only expect hint >=0, |
| -2, or -3. */ |
| |
| static tree |
| cxx_eval_dynamic_cast_fn (const constexpr_ctx *ctx, tree call, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| /* T will be something like |
| __dynamic_cast ((B*) b, &_ZTI1B, &_ZTI1D, 8) |
| dismantle it. */ |
| gcc_assert (call_expr_nargs (call) == 4); |
| tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
| tree obj = CALL_EXPR_ARG (call, 0); |
| tree type = CALL_EXPR_ARG (call, 2); |
| HOST_WIDE_INT hint = int_cst_value (CALL_EXPR_ARG (call, 3)); |
| location_t loc = cp_expr_loc_or_input_loc (call); |
| |
| /* Get the target type of the dynamic_cast. */ |
| gcc_assert (TREE_CODE (type) == ADDR_EXPR); |
| type = TREE_OPERAND (type, 0); |
| type = TREE_TYPE (DECL_NAME (type)); |
| |
| /* TYPE can only be either T* or T&. We can't know which of these it |
| is by looking at TYPE, but OBJ will be "(T*) x" in the first case, |
| and something like "(T*)(T&)(T*) x" in the second case. */ |
| bool reference_p = false; |
| while (CONVERT_EXPR_P (obj) || TREE_CODE (obj) == SAVE_EXPR) |
| { |
| reference_p |= TYPE_REF_P (TREE_TYPE (obj)); |
| obj = TREE_OPERAND (obj, 0); |
| } |
| |
| /* Evaluate the object so that we know its dynamic type. */ |
| obj = cxx_eval_constant_expression (ctx, obj, vc_prvalue, non_constant_p, |
| overflow_p); |
| if (*non_constant_p) |
| return call; |
| |
| /* We expect OBJ to be in form of &d.D.2102 when HINT == 0, |
| but when HINT is > 0, it can also be something like |
| &d.D.2102 + 18446744073709551608, which includes the BINFO_OFFSET. */ |
| obj = extract_obj_from_addr_offset (obj); |
| const tree objtype = TREE_TYPE (obj); |
| /* If OBJ doesn't refer to a base field, we're done. */ |
| if (tree t = (TREE_CODE (obj) == COMPONENT_REF |
| ? TREE_OPERAND (obj, 1) : obj)) |
| if (TREE_CODE (t) != FIELD_DECL || !DECL_FIELD_IS_BASE (t)) |
| { |
| if (reference_p) |
| { |
| if (!ctx->quiet) |
| { |
| error_at (loc, "reference %<dynamic_cast%> failed"); |
| inform (loc, "dynamic type %qT of its operand does " |
| "not have a base class of type %qT", |
| objtype, type); |
| } |
| *non_constant_p = true; |
| } |
| return integer_zero_node; |
| } |
| |
| /* [class.cdtor] When a dynamic_cast is used in a constructor ... |
| or in a destructor ... if the operand of the dynamic_cast refers |
| to the object under construction or destruction, this object is |
| considered to be a most derived object that has the type of the |
| constructor or destructor's class. */ |
| tree vtable = build_vfield_ref (obj, objtype); |
| vtable = cxx_eval_constant_expression (ctx, vtable, vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return call; |
| /* With -fsanitize=vptr, we initialize all vtable pointers to null, |
| so it's possible that we got a null pointer now. */ |
| if (integer_zerop (vtable)) |
| { |
| if (!ctx->quiet) |
| error_at (loc, "virtual table pointer is used uninitialized"); |
| *non_constant_p = true; |
| return integer_zero_node; |
| } |
| /* VTABLE will be &_ZTV1A + 16 or similar, get _ZTV1A. */ |
| vtable = extract_obj_from_addr_offset (vtable); |
| const tree mdtype = DECL_CONTEXT (vtable); |
| |
| /* Given dynamic_cast<T>(v), |
| |
| [expr.dynamic.cast] If C is the class type to which T points or refers, |
| the runtime check logically executes as follows: |
| |
| If, in the most derived object pointed (referred) to by v, v points |
| (refers) to a public base class subobject of a C object, and if only |
| one object of type C is derived from the subobject pointed (referred) |
| to by v the result points (refers) to that C object. |
| |
| In this case, HINT >= 0 or -3. */ |
| if (hint >= 0 || hint == -3) |
| { |
| /* Look for a component with type TYPE. */ |
| tree t = get_component_with_type (obj, type, mdtype); |
| /* If not accessible, give an error. */ |
| if (t == error_mark_node) |
| { |
| if (reference_p) |
| { |
| if (!ctx->quiet) |
| { |
| error_at (loc, "reference %<dynamic_cast%> failed"); |
| inform (loc, "static type %qT of its operand is a " |
| "non-public base class of dynamic type %qT", |
| objtype, type); |
| |
| } |
| *non_constant_p = true; |
| } |
| return integer_zero_node; |
| } |
| else if (t) |
| /* The result points to the TYPE object. */ |
| return cp_build_addr_expr (t, complain); |
| /* Else, TYPE was not found, because the HINT turned out to be wrong. |
| Fall through to the normal processing. */ |
| } |
| |
| /* Otherwise, if v points (refers) to a public base class subobject of the |
| most derived object, and the type of the most derived object has a base |
| class, of type C, that is unambiguous and public, the result points |
| (refers) to the C subobject of the most derived object. |
| |
| But it can also be an invalid case. */ |
| |
| /* Get the most derived object. */ |
| obj = get_component_with_type (obj, mdtype, NULL_TREE); |
| if (obj == error_mark_node) |
| { |
| if (reference_p) |
| { |
| if (!ctx->quiet) |
| { |
| error_at (loc, "reference %<dynamic_cast%> failed"); |
| inform (loc, "static type %qT of its operand is a non-public" |
| " base class of dynamic type %qT", objtype, mdtype); |
| } |
| *non_constant_p = true; |
| } |
| return integer_zero_node; |
| } |
| else |
| gcc_assert (obj); |
| |
| /* Check that the type of the most derived object has a base class |
| of type TYPE that is unambiguous and public. */ |
| base_kind b_kind; |
| tree binfo = lookup_base (mdtype, type, ba_check, &b_kind, tf_none); |
| if (!binfo || binfo == error_mark_node) |
| { |
| if (reference_p) |
| { |
| if (!ctx->quiet) |
| { |
| error_at (loc, "reference %<dynamic_cast%> failed"); |
| if (b_kind == bk_ambig) |
| inform (loc, "%qT is an ambiguous base class of dynamic " |
| "type %qT of its operand", type, mdtype); |
| else |
| inform (loc, "dynamic type %qT of its operand does not " |
| "have an unambiguous public base class %qT", |
| mdtype, type); |
| } |
| *non_constant_p = true; |
| } |
| return integer_zero_node; |
| } |
| /* If so, return the TYPE subobject of the most derived object. */ |
| obj = convert_to_base_statically (obj, binfo); |
| return cp_build_addr_expr (obj, complain); |
| } |
| |
| /* Data structure used by replace_decl and replace_decl_r. */ |
| |
| struct replace_decl_data |
| { |
| /* The _DECL we want to replace. */ |
| tree decl; |
| /* The replacement for DECL. */ |
| tree replacement; |
| /* Trees we've visited. */ |
| hash_set<tree> *pset; |
| /* Whether we've performed any replacements. */ |
| bool changed; |
| }; |
| |
| /* Helper function for replace_decl, called through cp_walk_tree. */ |
| |
| static tree |
| replace_decl_r (tree *tp, int *walk_subtrees, void *data) |
| { |
| replace_decl_data *d = (replace_decl_data *) data; |
| |
| if (*tp == d->decl) |
| { |
| *tp = unshare_expr (d->replacement); |
| d->changed = true; |
| *walk_subtrees = 0; |
| } |
| else if (TYPE_P (*tp) |
| || d->pset->add (*tp)) |
| *walk_subtrees = 0; |
| |
| return NULL_TREE; |
| } |
| |
| /* Replace every occurrence of DECL with (an unshared copy of) |
| REPLACEMENT within the expression *TP. Returns true iff a |
| replacement was performed. */ |
| |
| bool |
| replace_decl (tree *tp, tree decl, tree replacement) |
| { |
| gcc_checking_assert (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (decl), TREE_TYPE (replacement))); |
| hash_set<tree> pset; |
| replace_decl_data data = { decl, replacement, &pset, false }; |
| cp_walk_tree (tp, replace_decl_r, &data, NULL); |
| return data.changed; |
| } |
| |
| /* Evaluate the call T to virtual function thunk THUNK_FNDECL. */ |
| |
| static tree |
| cxx_eval_thunk_call (const constexpr_ctx *ctx, tree t, tree thunk_fndecl, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree function = THUNK_TARGET (thunk_fndecl); |
| |
| if (THUNK_VIRTUAL_OFFSET (thunk_fndecl)) |
| { |
| if (!ctx->quiet) |
| { |
| if (!DECL_DECLARED_CONSTEXPR_P (function)) |
| { |
| error ("call to non-%<constexpr%> function %qD", function); |
| explain_invalid_constexpr_fn (function); |
| } |
| else |
| /* virtual_offset is only set for virtual bases, which make the |
| class non-literal, so we don't need to handle it here. */ |
| error ("calling constexpr member function %qD through virtual " |
| "base subobject", function); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| |
| tree new_call = copy_node (t); |
| CALL_EXPR_FN (new_call) = function; |
| TREE_TYPE (new_call) = TREE_TYPE (TREE_TYPE (function)); |
| |
| tree offset = size_int (THUNK_FIXED_OFFSET (thunk_fndecl)); |
| |
| if (DECL_THIS_THUNK_P (thunk_fndecl)) |
| { |
| /* 'this'-adjusting thunk. */ |
| tree this_arg = CALL_EXPR_ARG (t, 0); |
| this_arg = build2 (POINTER_PLUS_EXPR, TREE_TYPE (this_arg), |
| this_arg, offset); |
| CALL_EXPR_ARG (new_call, 0) = this_arg; |
| } |
| else |
| /* Return-adjusting thunk. */ |
| new_call = build2 (POINTER_PLUS_EXPR, TREE_TYPE (new_call), |
| new_call, offset); |
| |
| return cxx_eval_constant_expression (ctx, new_call, lval, |
| non_constant_p, overflow_p); |
| } |
| |
| /* If OBJECT is of const class type, evaluate it to a CONSTRUCTOR and set |
| its TREE_READONLY flag according to READONLY_P. Used for constexpr |
| 'tors to detect modifying const objects in a constexpr context. */ |
| |
| static void |
| cxx_set_object_constness (const constexpr_ctx *ctx, tree object, |
| bool readonly_p, bool *non_constant_p, |
| bool *overflow_p) |
| { |
| if (CLASS_TYPE_P (TREE_TYPE (object)) |
| && CP_TYPE_CONST_P (TREE_TYPE (object))) |
| { |
| /* Subobjects might not be stored in ctx->global->values but we |
| can get its CONSTRUCTOR by evaluating *this. */ |
| tree e = cxx_eval_constant_expression (ctx, object, vc_prvalue, |
| non_constant_p, overflow_p); |
| if (TREE_CODE (e) == CONSTRUCTOR && !*non_constant_p) |
| TREE_READONLY (e) = readonly_p; |
| } |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Evaluate the call expression tree T in the context of OLD_CALL expression |
| evaluation. */ |
| |
| static tree |
| cxx_eval_call_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| /* Handle concept checks separately. */ |
| if (concept_check_p (t)) |
| return evaluate_concept_check (t); |
| |
| location_t loc = cp_expr_loc_or_input_loc (t); |
| tree fun = get_function_named_in_call (t); |
| constexpr_call new_call |
| = { NULL, NULL, NULL, 0, ctx->manifestly_const_eval }; |
| int depth_ok; |
| |
| if (fun == NULL_TREE) |
| return cxx_eval_internal_function (ctx, t, lval, |
| non_constant_p, overflow_p); |
| |
| if (TREE_CODE (fun) != FUNCTION_DECL) |
| { |
| /* Might be a constexpr function pointer. */ |
| fun = cxx_eval_constant_expression (ctx, fun, vc_prvalue, |
| non_constant_p, overflow_p); |
| STRIP_NOPS (fun); |
| if (TREE_CODE (fun) == ADDR_EXPR) |
| fun = TREE_OPERAND (fun, 0); |
| /* For TARGET_VTABLE_USES_DESCRIPTORS targets, there is no |
| indirection, the called expression is a pointer into the |
| virtual table which should contain FDESC_EXPR. Extract the |
| FUNCTION_DECL from there. */ |
| else if (TARGET_VTABLE_USES_DESCRIPTORS |
| && TREE_CODE (fun) == POINTER_PLUS_EXPR |
| && TREE_CODE (TREE_OPERAND (fun, 0)) == ADDR_EXPR |
| && TREE_CODE (TREE_OPERAND (fun, 1)) == INTEGER_CST) |
| { |
| tree d = TREE_OPERAND (TREE_OPERAND (fun, 0), 0); |
| if (VAR_P (d) |
| && DECL_VTABLE_OR_VTT_P (d) |
| && TREE_CODE (TREE_TYPE (d)) == ARRAY_TYPE |
| && TREE_TYPE (TREE_TYPE (d)) == vtable_entry_type |
| && DECL_INITIAL (d) |
| && TREE_CODE (DECL_INITIAL (d)) == CONSTRUCTOR) |
| { |
| tree i = int_const_binop (TRUNC_DIV_EXPR, TREE_OPERAND (fun, 1), |
| TYPE_SIZE_UNIT (vtable_entry_type)); |
| HOST_WIDE_INT idx = find_array_ctor_elt (DECL_INITIAL (d), i); |
| if (idx >= 0) |
| { |
| tree fdesc |
| = (*CONSTRUCTOR_ELTS (DECL_INITIAL (d)))[idx].value; |
| if (TREE_CODE (fdesc) == FDESC_EXPR |
| && integer_zerop (TREE_OPERAND (fdesc, 1))) |
| fun = TREE_OPERAND (fdesc, 0); |
| } |
| } |
| } |
| } |
| if (TREE_CODE (fun) != FUNCTION_DECL) |
| { |
| if (!ctx->quiet && !*non_constant_p) |
| error_at (loc, "expression %qE does not designate a %<constexpr%> " |
| "function", fun); |
| *non_constant_p = true; |
| return t; |
| } |
| if (DECL_CLONED_FUNCTION_P (fun) && !DECL_DELETING_DESTRUCTOR_P (fun)) |
| fun = DECL_CLONED_FUNCTION (fun); |
| |
| if (is_ubsan_builtin_p (fun)) |
| return void_node; |
| |
| if (fndecl_built_in_p (fun)) |
| return cxx_eval_builtin_function_call (ctx, t, fun, |
| lval, non_constant_p, overflow_p); |
| if (DECL_THUNK_P (fun)) |
| return cxx_eval_thunk_call (ctx, t, fun, lval, non_constant_p, overflow_p); |
| if (!maybe_constexpr_fn (fun)) |
| { |
| if (TREE_CODE (t) == CALL_EXPR |
| && cxx_replaceable_global_alloc_fn (fun) |
| && (CALL_FROM_NEW_OR_DELETE_P (t) |
| || is_std_allocator_allocate (ctx->call))) |
| { |
| const int nargs = call_expr_nargs (t); |
| tree arg0 = NULL_TREE; |
| for (int i = 0; i < nargs; ++i) |
| { |
| tree arg = CALL_EXPR_ARG (t, i); |
| arg = cxx_eval_constant_expression (ctx, arg, vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (arg); |
| if (i == 0) |
| arg0 = arg; |
| } |
| gcc_assert (arg0); |
| if (IDENTIFIER_NEW_OP_P (DECL_NAME (fun))) |
| { |
| tree type = build_array_type_nelts (char_type_node, |
| tree_to_uhwi (arg0)); |
| tree var = build_decl (loc, VAR_DECL, |
| (IDENTIFIER_OVL_OP_FLAGS (DECL_NAME (fun)) |
| & OVL_OP_FLAG_VEC) |
| ? heap_vec_uninit_identifier |
| : heap_uninit_identifier, |
| type); |
| DECL_ARTIFICIAL (var) = 1; |
| TREE_STATIC (var) = 1; |
| // Temporarily register the artificial var in varpool, |
| // so that comparisons of its address against NULL are folded |
| // through nonzero_address even with |
| // -fno-delete-null-pointer-checks or that comparison of |
| // addresses of different heap artificial vars is folded too. |
| // See PR98988 and PR99031. |
| varpool_node::finalize_decl (var); |
| ctx->global->heap_vars.safe_push (var); |
| ctx->global->put_value (var, NULL_TREE); |
| return fold_convert (ptr_type_node, build_address (var)); |
| } |
| else |
| { |
| STRIP_NOPS (arg0); |
| if (TREE_CODE (arg0) == ADDR_EXPR |
| && VAR_P (TREE_OPERAND (arg0, 0))) |
| { |
| tree var = TREE_OPERAND (arg0, 0); |
| if (DECL_NAME (var) == heap_uninit_identifier |
| || DECL_NAME (var) == heap_identifier) |
| { |
| if (IDENTIFIER_OVL_OP_FLAGS (DECL_NAME (fun)) |
| & OVL_OP_FLAG_VEC) |
| { |
| if (!ctx->quiet) |
| { |
| error_at (loc, "array deallocation of object " |
| "allocated with non-array " |
| "allocation"); |
| inform (DECL_SOURCE_LOCATION (var), |
| "allocation performed here"); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| DECL_NAME (var) = heap_deleted_identifier; |
| ctx->global->remove_value (var); |
| ctx->global->heap_dealloc_count++; |
| return void_node; |
| } |
| else if (DECL_NAME (var) == heap_vec_uninit_identifier |
| || DECL_NAME (var) == heap_vec_identifier) |
| { |
| if ((IDENTIFIER_OVL_OP_FLAGS (DECL_NAME (fun)) |
| & OVL_OP_FLAG_VEC) == 0) |
| { |
| if (!ctx->quiet) |
| { |
| error_at (loc, "non-array deallocation of " |
| "object allocated with array " |
| "allocation"); |
| inform (DECL_SOURCE_LOCATION (var), |
| "allocation performed here"); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| DECL_NAME (var) = heap_deleted_identifier; |
| ctx->global->remove_value (var); |
| ctx->global->heap_dealloc_count++; |
| return void_node; |
| } |
| else if (DECL_NAME (var) == heap_deleted_identifier) |
| { |
| if (!ctx->quiet) |
| error_at (loc, "deallocation of already deallocated " |
| "storage"); |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| if (!ctx->quiet) |
| error_at (loc, "deallocation of storage that was " |
| "not previously allocated"); |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| /* Allow placement new in std::construct_at, just return the second |
| argument. */ |
| if (TREE_CODE (t) == CALL_EXPR |
| && cxx_placement_new_fn (fun) |
| && is_std_construct_at (ctx->call)) |
| { |
| const int nargs = call_expr_nargs (t); |
| tree arg1 = NULL_TREE; |
| for (int i = 0; i < nargs; ++i) |
| { |
| tree arg = CALL_EXPR_ARG (t, i); |
| arg = cxx_eval_constant_expression (ctx, arg, vc_prvalue, |
| non_constant_p, overflow_p); |
| if (i == 1) |
| arg1 = arg; |
| else |
| VERIFY_CONSTANT (arg); |
| } |
| gcc_assert (arg1); |
| return arg1; |
| } |
| else if (cxx_dynamic_cast_fn_p (fun)) |
| return cxx_eval_dynamic_cast_fn (ctx, t, non_constant_p, overflow_p); |
| |
| if (!ctx->quiet) |
| { |
| if (!lambda_static_thunk_p (fun)) |
| error_at (loc, "call to non-%<constexpr%> function %qD", fun); |
| explain_invalid_constexpr_fn (fun); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| |
| constexpr_ctx new_ctx = *ctx; |
| if (DECL_CONSTRUCTOR_P (fun) && !ctx->object |
| && TREE_CODE (t) == AGGR_INIT_EXPR) |
| { |
| /* We want to have an initialization target for an AGGR_INIT_EXPR. |
| If we don't already have one in CTX, use the AGGR_INIT_EXPR_SLOT. */ |
| new_ctx.object = AGGR_INIT_EXPR_SLOT (t); |
| tree ctor = new_ctx.ctor = build_constructor (DECL_CONTEXT (fun), NULL); |
| CONSTRUCTOR_NO_CLEARING (ctor) = true; |
| ctx->global->put_value (new_ctx.object, ctor); |
| ctx = &new_ctx; |
| } |
| |
| /* Shortcut trivial constructor/op=. */ |
| if (trivial_fn_p (fun)) |
| { |
| tree init = NULL_TREE; |
| if (call_expr_nargs (t) == 2) |
| init = convert_from_reference (get_nth_callarg (t, 1)); |
| else if (TREE_CODE (t) == AGGR_INIT_EXPR |
| && AGGR_INIT_ZERO_FIRST (t)) |
| init = build_zero_init (DECL_CONTEXT (fun), NULL_TREE, false); |
| if (init) |
| { |
| tree op = get_nth_callarg (t, 0); |
| if (is_dummy_object (op)) |
| op = ctx->object; |
| else |
| op = build1 (INDIRECT_REF, TREE_TYPE (TREE_TYPE (op)), op); |
| tree set = build2 (MODIFY_EXPR, TREE_TYPE (op), op, init); |
| new_ctx.call = &new_call; |
| return cxx_eval_constant_expression (&new_ctx, set, lval, |
| non_constant_p, overflow_p); |
| } |
| } |
| |
| bool non_constant_args = false; |
| new_call.bindings |
| = cxx_bind_parameters_in_call (ctx, t, fun, non_constant_p, |
| overflow_p, &non_constant_args); |
| |
| /* We build up the bindings list before we know whether we already have this |
| call cached. If we don't end up saving these bindings, ggc_free them when |
| this function exits. */ |
| class free_bindings |
| { |
| tree *bindings; |
| public: |
| free_bindings (tree &b): bindings (&b) { } |
| ~free_bindings () { if (bindings) ggc_free (*bindings); } |
| void preserve () { bindings = NULL; } |
| } fb (new_call.bindings); |
| |
| if (*non_constant_p) |
| return t; |
| |
| /* We can't defer instantiating the function any longer. */ |
| if (!DECL_INITIAL (fun) |
| && DECL_TEMPLOID_INSTANTIATION (fun) |
| && !uid_sensitive_constexpr_evaluation_p ()) |
| { |
| location_t save_loc = input_location; |
| input_location = loc; |
| ++function_depth; |
| if (ctx->manifestly_const_eval) |
| FNDECL_MANIFESTLY_CONST_EVALUATED (fun) = true; |
| instantiate_decl (fun, /*defer_ok*/false, /*expl_inst*/false); |
| --function_depth; |
| input_location = save_loc; |
| } |
| |
| /* If in direct recursive call, optimize definition search. */ |
| if (ctx && ctx->call && ctx->call->fundef && ctx->call->fundef->decl == fun) |
| new_call.fundef = ctx->call->fundef; |
| else |
| { |
| new_call.fundef = retrieve_constexpr_fundef (fun); |
| if (new_call.fundef == NULL || new_call.fundef->body == NULL |
| || new_call.fundef->result == error_mark_node |
| || fun == current_function_decl) |
| { |
| if (!ctx->quiet) |
| { |
| /* We need to check for current_function_decl here in case we're |
| being called during cp_fold_function, because at that point |
| DECL_INITIAL is set properly and we have a fundef but we |
| haven't lowered invisirefs yet (c++/70344). */ |
| if (DECL_INITIAL (fun) == error_mark_node |
| || fun == current_function_decl) |
| error_at (loc, "%qD called in a constant expression before its " |
| "definition is complete", fun); |
| else if (DECL_INITIAL (fun)) |
| { |
| /* The definition of fun was somehow unsuitable. But pretend |
| that lambda static thunks don't exist. */ |
| if (!lambda_static_thunk_p (fun)) |
| error_at (loc, "%qD called in a constant expression", fun); |
| explain_invalid_constexpr_fn (fun); |
| } |
| else |
| error_at (loc, "%qD used before its definition", fun); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| |
| depth_ok = push_cx_call_context (t); |
| |
| /* Remember the object we are constructing or destructing. */ |
| tree new_obj = NULL_TREE; |
| if (DECL_CONSTRUCTOR_P (fun) || DECL_DESTRUCTOR_P (fun)) |
| { |
| /* In a cdtor, it should be the first `this' argument. |
| At this point it has already been evaluated in the call |
| to cxx_bind_parameters_in_call. */ |
| new_obj = TREE_VEC_ELT (new_call.bindings, 0); |
| new_obj = cxx_fold_indirect_ref (ctx, loc, DECL_CONTEXT (fun), new_obj); |
| |
| if (ctx->call && ctx->call->fundef |
| && DECL_CONSTRUCTOR_P (ctx->call->fundef->decl)) |
| { |
| tree cur_obj = TREE_VEC_ELT (ctx->call->bindings, 0); |
| STRIP_NOPS (cur_obj); |
| if (TREE_CODE (cur_obj) == ADDR_EXPR) |
| cur_obj = TREE_OPERAND (cur_obj, 0); |
| if (new_obj == cur_obj) |
| /* We're calling the target constructor of a delegating |
| constructor, or accessing a base subobject through a |
| NOP_EXPR as part of a call to a base constructor, so |
| there is no new (sub)object. */ |
| new_obj = NULL_TREE; |
| } |
| } |
| |
| tree result = NULL_TREE; |
| |
| constexpr_call *entry = NULL; |
| if (depth_ok && !non_constant_args && ctx->strict) |
| { |
| new_call.hash = constexpr_fundef_hasher::hash (new_call.fundef); |
| new_call.hash |
| = iterative_hash_template_arg (new_call.bindings, new_call.hash); |
| new_call.hash |
| = iterative_hash_object (ctx->manifestly_const_eval, new_call.hash); |
| |
| /* If we have seen this call before, we are done. */ |
| maybe_initialize_constexpr_call_table (); |
| bool insert = depth_ok < constexpr_cache_depth; |
| constexpr_call **slot |
| = constexpr_call_table->find_slot (&new_call, |
| insert ? INSERT : NO_INSERT); |
| entry = slot ? *slot : NULL; |
| if (entry == NULL) |
| { |
| /* Only cache up to constexpr_cache_depth to limit memory use. */ |
| if (insert) |
| { |
| /* We need to keep a pointer to the entry, not just the slot, as |
| the slot can move during evaluation of the body. */ |
| *slot = entry = ggc_alloc<constexpr_call> (); |
| *entry = new_call; |
| fb.preserve (); |
| } |
| } |
| /* Calls that are in progress have their result set to NULL, so that we |
| can detect circular dependencies. Now that we only cache up to |
| constexpr_cache_depth this won't catch circular dependencies that |
| start deeper, but they'll hit the recursion or ops limit. */ |
| else if (entry->result == NULL) |
| { |
| if (!ctx->quiet) |
| error ("call has circular dependency"); |
| *non_constant_p = true; |
| entry->result = result = error_mark_node; |
| } |
| else |
| result = entry->result; |
| } |
| |
| if (!depth_ok) |
| { |
| if (!ctx->quiet) |
| error ("%<constexpr%> evaluation depth exceeds maximum of %d (use " |
| "%<-fconstexpr-depth=%> to increase the maximum)", |
| max_constexpr_depth); |
| *non_constant_p = true; |
| result = error_mark_node; |
| } |
| else |
| { |
| bool cacheable = true; |
| if (result && result != error_mark_node) |
| /* OK */; |
| else if (!DECL_SAVED_TREE (fun)) |
| { |
| /* When at_eof >= 2, cgraph has started throwing away |
| DECL_SAVED_TREE, so fail quietly. FIXME we get here because of |
| late code generation for VEC_INIT_EXPR, which needs to be |
| completely reconsidered. */ |
| gcc_assert (at_eof >= 2 && ctx->quiet); |
| *non_constant_p = true; |
| } |
| else if (tree copy = get_fundef_copy (new_call.fundef)) |
| { |
| tree body, parms, res; |
| releasing_vec ctors; |
| |
| /* Reuse or create a new unshared copy of this function's body. */ |
| body = TREE_PURPOSE (copy); |
| parms = TREE_VALUE (copy); |
| res = TREE_TYPE (copy); |
| |
| /* Associate the bindings with the remapped parms. */ |
| tree bound = new_call.bindings; |
| tree remapped = parms; |
| for (int i = 0; i < TREE_VEC_LENGTH (bound); ++i) |
| { |
| tree arg = TREE_VEC_ELT (bound, i); |
| if (entry) |
| { |
| /* Unshare args going into the hash table to separate them |
| from the caller's context, for better GC and to avoid |
| problems with verify_gimple. */ |
| arg = unshare_expr_without_location (arg); |
| TREE_VEC_ELT (bound, i) = arg; |
| |
| /* And then unshare again so the callee doesn't change the |
| argument values in the hash table. XXX Could we unshare |
| lazily in cxx_eval_store_expression? */ |
| arg = unshare_constructor (arg); |
| if (TREE_CODE (arg) == CONSTRUCTOR) |
| vec_safe_push (ctors, arg); |
| } |
| ctx->global->put_value (remapped, arg); |
| remapped = DECL_CHAIN (remapped); |
| } |
| /* Add the RESULT_DECL to the values map, too. */ |
| gcc_assert (!DECL_BY_REFERENCE (res)); |
| ctx->global->put_value (res, NULL_TREE); |
| |
| /* Track the callee's evaluated SAVE_EXPRs and TARGET_EXPRs so that |
| we can forget their values after the call. */ |
| constexpr_ctx ctx_with_save_exprs = *ctx; |
| auto_vec<tree, 10> save_exprs; |
| ctx_with_save_exprs.save_exprs = &save_exprs; |
| ctx_with_save_exprs.call = &new_call; |
| unsigned save_heap_alloc_count = ctx->global->heap_vars.length (); |
| unsigned save_heap_dealloc_count = ctx->global->heap_dealloc_count; |
| |
| /* If this is a constexpr destructor, the object's const and volatile |
| semantics are no longer in effect; see [class.dtor]p5. */ |
| if (new_obj && DECL_DESTRUCTOR_P (fun)) |
| cxx_set_object_constness (ctx, new_obj, /*readonly_p=*/false, |
| non_constant_p, overflow_p); |
| |
| tree jump_target = NULL_TREE; |
| cxx_eval_constant_expression (&ctx_with_save_exprs, body, |
| vc_discard, non_constant_p, overflow_p, |
| &jump_target); |
| |
| if (DECL_CONSTRUCTOR_P (fun)) |
| { |
| /* This can be null for a subobject constructor call, in |
| which case what we care about is the initialization |
| side-effects rather than the value. We could get at the |
| value by evaluating *this, but we don't bother; there's |
| no need to put such a call in the hash table. */ |
| result = lval ? ctx->object : ctx->ctor; |
| |
| /* If we've just evaluated a subobject constructor call for an |
| empty union member, it might not have produced a side effect |
| that actually activated the union member. So produce such a |
| side effect now to ensure the union appears initialized. */ |
| if (!result && new_obj |
| && TREE_CODE (new_obj) == COMPONENT_REF |
| && TREE_CODE (TREE_TYPE |
| (TREE_OPERAND (new_obj, 0))) == UNION_TYPE |
| && is_really_empty_class (TREE_TYPE (new_obj), |
| /*ignore_vptr*/false)) |
| { |
| tree activate = build2 (MODIFY_EXPR, TREE_TYPE (new_obj), |
| new_obj, |
| build_constructor (TREE_TYPE (new_obj), |
| NULL)); |
| cxx_eval_constant_expression (ctx, activate, lval, |
| non_constant_p, overflow_p); |
| ggc_free (activate); |
| } |
| } |
| else if (VOID_TYPE_P (TREE_TYPE (res))) |
| result = void_node; |
| else |
| { |
| result = ctx->global->get_value (res); |
| if (result == NULL_TREE && !*non_constant_p |
| && !DECL_DESTRUCTOR_P (fun)) |
| { |
| if (!ctx->quiet) |
| error ("%<constexpr%> call flows off the end " |
| "of the function"); |
| *non_constant_p = true; |
| } |
| } |
| |
| /* At this point, the object's constructor will have run, so |
| the object is no longer under construction, and its possible |
| 'const' semantics now apply. Make a note of this fact by |
| marking the CONSTRUCTOR TREE_READONLY. */ |
| if (new_obj && DECL_CONSTRUCTOR_P (fun)) |
| cxx_set_object_constness (ctx, new_obj, /*readonly_p=*/true, |
| non_constant_p, overflow_p); |
| |
| /* Forget the saved values of the callee's SAVE_EXPRs and |
| TARGET_EXPRs. */ |
| for (tree save_expr : save_exprs) |
| ctx->global->remove_value (save_expr); |
| |
| /* Remove the parms/result from the values map. Is it worth |
| bothering to do this when the map itself is only live for |
| one constexpr evaluation? If so, maybe also clear out |
| other vars from call, maybe in BIND_EXPR handling? */ |
| ctx->global->remove_value (res); |
| for (tree parm = parms; parm; parm = TREE_CHAIN (parm)) |
| ctx->global->remove_value (parm); |
| |
| /* Free any parameter CONSTRUCTORs we aren't returning directly. */ |
| while (!ctors->is_empty ()) |
| { |
| tree c = ctors->pop (); |
| if (c != result) |
| free_constructor (c); |
| } |
| |
| /* Make the unshared function copy we used available for re-use. */ |
| save_fundef_copy (fun, copy); |
| |
| /* If the call allocated some heap object that hasn't been |
| deallocated during the call, or if it deallocated some heap |
| object it has not allocated, the call isn't really stateless |
| for the constexpr evaluation and should not be cached. |
| It is fine if the call allocates something and deallocates it |
| too. */ |
| if (entry |
| && (save_heap_alloc_count != ctx->global->heap_vars.length () |
| || (save_heap_dealloc_count |
| != ctx->global->heap_dealloc_count))) |
| { |
| tree heap_var; |
| unsigned int i; |
| if ((ctx->global->heap_vars.length () |
| - ctx->global->heap_dealloc_count) |
| != save_heap_alloc_count - save_heap_dealloc_count) |
| cacheable = false; |
| else |
| FOR_EACH_VEC_ELT_FROM (ctx->global->heap_vars, i, heap_var, |
| save_heap_alloc_count) |
| if (DECL_NAME (heap_var) != heap_deleted_identifier) |
| { |
| cacheable = false; |
| break; |
| } |
| /* Also don't cache a call that returns a deallocated pointer. */ |
| if (cacheable && (cp_walk_tree_without_duplicates |
| (&result, find_heap_var_refs, NULL))) |
| cacheable = false; |
| } |
| |
| /* Rewrite all occurrences of the function's RESULT_DECL with the |
| current object under construction. */ |
| if (!*non_constant_p && ctx->object |
| && CLASS_TYPE_P (TREE_TYPE (res)) |
| && !is_empty_class (TREE_TYPE (res))) |
| if (replace_decl (&result, res, ctx->object)) |
| cacheable = false; |
| } |
| else |
| /* Couldn't get a function copy to evaluate. */ |
| *non_constant_p = true; |
| |
| if (result == error_mark_node) |
| *non_constant_p = true; |
| if (*non_constant_p || *overflow_p) |
| result = error_mark_node; |
| else if (!result) |
| result = void_node; |
| if (entry) |
| entry->result = cacheable ? result : error_mark_node; |
| } |
| |
| /* The result of a constexpr function must be completely initialized. |
| |
| However, in C++20, a constexpr constructor doesn't necessarily have |
| to initialize all the fields, so we don't clear CONSTRUCTOR_NO_CLEARING |
| in order to detect reading an unitialized object in constexpr instead |
| of value-initializing it. (reduced_constant_expression_p is expected to |
| take care of clearing the flag.) */ |
| if (TREE_CODE (result) == CONSTRUCTOR |
| && (cxx_dialect < cxx20 |
| || !DECL_CONSTRUCTOR_P (fun))) |
| clear_no_implicit_zero (result); |
| |
| pop_cx_call_context (); |
| return result; |
| } |
| |
| /* Return true if T is a valid constant initializer. If a CONSTRUCTOR |
| initializes all the members, the CONSTRUCTOR_NO_CLEARING flag will be |
| cleared. |
| FIXME speed this up, it's taking 16% of compile time on sieve testcase. */ |
| |
| bool |
| reduced_constant_expression_p (tree t) |
| { |
| if (t == NULL_TREE) |
| return false; |
| |
| switch (TREE_CODE (t)) |
| { |
| case PTRMEM_CST: |
| /* Even if we can't lower this yet, it's constant. */ |
| return true; |
| |
| case CONSTRUCTOR: |
| /* And we need to handle PTRMEM_CST wrapped in a CONSTRUCTOR. */ |
| tree field; |
| if (TREE_CODE (TREE_TYPE (t)) == VECTOR_TYPE) |
| /* An initialized vector would have a VECTOR_CST. */ |
| return false; |
| if (CONSTRUCTOR_NO_CLEARING (t)) |
| { |
| if (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE) |
| { |
| /* There must be a valid constant initializer at every array |
| index. */ |
| tree min = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (t))); |
| tree max = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (t))); |
| tree cursor = min; |
| for (auto &e: CONSTRUCTOR_ELTS (t)) |
| { |
| if (!reduced_constant_expression_p (e.value)) |
| return false; |
| if (array_index_cmp (cursor, e.index) != 0) |
| return false; |
| if (TREE_CODE (e.index) == RANGE_EXPR) |
| cursor = TREE_OPERAND (e.index, 1); |
| cursor = int_const_binop (PLUS_EXPR, cursor, size_one_node); |
| } |
| if (find_array_ctor_elt (t, max) == -1) |
| return false; |
| goto ok; |
| } |
| else if (cxx_dialect >= cxx20 |
| && TREE_CODE (TREE_TYPE (t)) == UNION_TYPE) |
| { |
| if (CONSTRUCTOR_NELTS (t) == 0) |
| /* An initialized union has a constructor element. */ |
| return false; |
| /* And it only initializes one member. */ |
| field = NULL_TREE; |
| } |
| else |
| field = next_subobject_field (TYPE_FIELDS (TREE_TYPE (t))); |
| } |
| else |
| field = NULL_TREE; |
| for (auto &e: CONSTRUCTOR_ELTS (t)) |
| { |
| /* If VAL is null, we're in the middle of initializing this |
| element. */ |
| if (!reduced_constant_expression_p (e.value)) |
| return false; |
| /* We want to remove initializers for empty fields in a struct to |
| avoid confusing output_constructor. */ |
| if (is_empty_field (e.index) |
| && TREE_CODE (TREE_TYPE (t)) == RECORD_TYPE) |
| return false; |
| /* Check for non-empty fields between initialized fields when |
| CONSTRUCTOR_NO_CLEARING. */ |
| for (; field && e.index != field; |
| field = next_subobject_field (DECL_CHAIN (field))) |
| if (!is_really_empty_class (TREE_TYPE (field), |
| /*ignore_vptr*/false)) |
| return false; |
| if (field) |
| field = next_subobject_field (DECL_CHAIN (field)); |
| } |
| /* There could be a non-empty field at the end. */ |
| for (; field; field = next_subobject_field (DECL_CHAIN (field))) |
| if (!is_really_empty_class (TREE_TYPE (field), /*ignore_vptr*/false)) |
| return false; |
| ok: |
| if (CONSTRUCTOR_NO_CLEARING (t)) |
| /* All the fields are initialized. */ |
| CONSTRUCTOR_NO_CLEARING (t) = false; |
| return true; |
| |
| default: |
| /* FIXME are we calling this too much? */ |
| return initializer_constant_valid_p (t, TREE_TYPE (t)) != NULL_TREE; |
| } |
| } |
| |
| /* Some expressions may have constant operands but are not constant |
| themselves, such as 1/0. Call this function to check for that |
| condition. |
| |
| We only call this in places that require an arithmetic constant, not in |
| places where we might have a non-constant expression that can be a |
| component of a constant expression, such as the address of a constexpr |
| variable that might be dereferenced later. */ |
| |
| static bool |
| verify_constant (tree t, bool allow_non_constant, bool *non_constant_p, |
| bool *overflow_p) |
| { |
| if (!*non_constant_p && !reduced_constant_expression_p (t) |
| && t != void_node) |
| { |
| if (!allow_non_constant) |
| error ("%q+E is not a constant expression", t); |
| *non_constant_p = true; |
| } |
| if (TREE_OVERFLOW_P (t)) |
| { |
| if (!allow_non_constant) |
| { |
| permerror (input_location, "overflow in constant expression"); |
| /* If we're being permissive (and are in an enforcing |
| context), ignore the overflow. */ |
| if (flag_permissive) |
| return *non_constant_p; |
| } |
| *overflow_p = true; |
| } |
| return *non_constant_p; |
| } |
| |
| /* Check whether the shift operation with code CODE and type TYPE on LHS |
| and RHS is undefined. If it is, give an error with an explanation, |
| and return true; return false otherwise. */ |
| |
| static bool |
| cxx_eval_check_shift_p (location_t loc, const constexpr_ctx *ctx, |
| enum tree_code code, tree type, tree lhs, tree rhs) |
| { |
| if ((code != LSHIFT_EXPR && code != RSHIFT_EXPR) |
| || TREE_CODE (lhs) != INTEGER_CST |
| || TREE_CODE (rhs) != INTEGER_CST) |
| return false; |
| |
| tree lhstype = TREE_TYPE (lhs); |
| unsigned HOST_WIDE_INT uprec = TYPE_PRECISION (TREE_TYPE (lhs)); |
| |
| /* [expr.shift] The behavior is undefined if the right operand |
| is negative, or greater than or equal to the length in bits |
| of the promoted left operand. */ |
| if (tree_int_cst_sgn (rhs) == -1) |
| { |
| if (!ctx->quiet) |
| permerror (loc, "right operand of shift expression %q+E is negative", |
| build2_loc (loc, code, type, lhs, rhs)); |
| return (!flag_permissive || ctx->quiet); |
| } |
| if (compare_tree_int (rhs, uprec) >= 0) |
| { |
| if (!ctx->quiet) |
| permerror (loc, "right operand of shift expression %q+E is greater " |
| "than or equal to the precision %wu of the left operand", |
| build2_loc (loc, code, type, lhs, rhs), uprec); |
| return (!flag_permissive || ctx->quiet); |
| } |
| |
| /* The value of E1 << E2 is E1 left-shifted E2 bit positions; [...] |
| if E1 has a signed type and non-negative value, and E1x2^E2 is |
| representable in the corresponding unsigned type of the result type, |
| then that value, converted to the result type, is the resulting value; |
| otherwise, the behavior is undefined. |
| For C++20: |
| The value of E1 << E2 is the unique value congruent to E1 x 2^E2 modulo |
| 2^N, where N is the range exponent of the type of the result. */ |
| if (code == LSHIFT_EXPR |
| && !TYPE_OVERFLOW_WRAPS (lhstype) |
| && cxx_dialect >= cxx11 |
| && cxx_dialect < cxx20) |
| { |
| if (tree_int_cst_sgn (lhs) == -1) |
| { |
| if (!ctx->quiet) |
| permerror (loc, |
| "left operand of shift expression %q+E is negative", |
| build2_loc (loc, code, type, lhs, rhs)); |
| return (!flag_permissive || ctx->quiet); |
| } |
| /* For signed x << y the following: |
| (unsigned) x >> ((prec (lhs) - 1) - y) |
| if > 1, is undefined. The right-hand side of this formula |
| is the highest bit of the LHS that can be set (starting from 0), |
| so that the shift doesn't overflow. We then right-shift the LHS |
| to see whether any other bit is set making the original shift |
| undefined -- the result is not representable in the corresponding |
| unsigned type. */ |
| tree t = build_int_cst (unsigned_type_node, uprec - 1); |
| t = fold_build2 (MINUS_EXPR, unsigned_type_node, t, rhs); |
| tree ulhs = fold_convert (unsigned_type_for (lhstype), lhs); |
| t = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ulhs), ulhs, t); |
| if (tree_int_cst_lt (integer_one_node, t)) |
| { |
| if (!ctx->quiet) |
| permerror (loc, "shift expression %q+E overflows", |
| build2_loc (loc, code, type, lhs, rhs)); |
| return (!flag_permissive || ctx->quiet); |
| } |
| } |
| return false; |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to reduce the unary expression tree T to a compile time value. |
| If successful, return the value. Otherwise issue a diagnostic |
| and return error_mark_node. */ |
| |
| static tree |
| cxx_eval_unary_expression (const constexpr_ctx *ctx, tree t, |
| bool /*lval*/, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree r; |
| tree orig_arg = TREE_OPERAND (t, 0); |
| tree arg = cxx_eval_constant_expression (ctx, orig_arg, vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (arg); |
| location_t loc = EXPR_LOCATION (t); |
| enum tree_code code = TREE_CODE (t); |
| tree type = TREE_TYPE (t); |
| r = fold_unary_loc (loc, code, type, arg); |
| if (r == NULL_TREE) |
| { |
| if (arg == orig_arg) |
| r = t; |
| else |
| r = build1_loc (loc, code, type, arg); |
| } |
| VERIFY_CONSTANT (r); |
| return r; |
| } |
| |
| /* Helper function for cxx_eval_binary_expression. Try to optimize |
| original POINTER_PLUS_EXPR T, LHS p+ RHS, return NULL_TREE if the |
| generic folding should be used. */ |
| |
| static tree |
| cxx_fold_pointer_plus_expression (const constexpr_ctx *ctx, tree t, |
| tree lhs, tree rhs, bool *non_constant_p, |
| bool *overflow_p) |
| { |
| STRIP_NOPS (lhs); |
| if (TREE_CODE (lhs) != ADDR_EXPR) |
| return NULL_TREE; |
| |
| lhs = TREE_OPERAND (lhs, 0); |
| |
| /* &A[i] p+ j => &A[i + j] */ |
| if (TREE_CODE (lhs) == ARRAY_REF |
| && TREE_CODE (TREE_OPERAND (lhs, 1)) == INTEGER_CST |
| && TREE_CODE (rhs) == INTEGER_CST |
| && TYPE_SIZE_UNIT (TREE_TYPE (lhs)) |
| && TREE_CODE (TYPE_SIZE_UNIT (TREE_TYPE (lhs))) == INTEGER_CST) |
| { |
| tree orig_type = TREE_TYPE (t); |
| location_t loc = EXPR_LOCATION (t); |
| tree type = TREE_TYPE (lhs); |
| |
| t = fold_convert_loc (loc, ssizetype, TREE_OPERAND (lhs, 1)); |
| tree nelts = array_type_nelts_top (TREE_TYPE (TREE_OPERAND (lhs, 0))); |
| nelts = cxx_eval_constant_expression (ctx, nelts, vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return NULL_TREE; |
| /* Don't fold an out-of-bound access. */ |
| if (!tree_int_cst_le (t, nelts)) |
| return NULL_TREE; |
| rhs = cp_fold_convert (ssizetype, rhs); |
| /* Don't fold if rhs can't be divided exactly by TYPE_SIZE_UNIT. |
| constexpr int A[1]; ... (char *)&A[0] + 1 */ |
| if (!integer_zerop (fold_build2_loc (loc, TRUNC_MOD_EXPR, sizetype, |
| rhs, TYPE_SIZE_UNIT (type)))) |
| return NULL_TREE; |
| /* Make sure to treat the second operand of POINTER_PLUS_EXPR |
| as signed. */ |
| rhs = fold_build2_loc (loc, EXACT_DIV_EXPR, ssizetype, rhs, |
| TYPE_SIZE_UNIT (type)); |
| t = size_binop_loc (loc, PLUS_EXPR, rhs, t); |
| t = build4_loc (loc, ARRAY_REF, type, TREE_OPERAND (lhs, 0), |
| t, NULL_TREE, NULL_TREE); |
| t = cp_build_addr_expr (t, tf_warning_or_error); |
| t = cp_fold_convert (orig_type, t); |
| return cxx_eval_constant_expression (ctx, t, vc_prvalue, |
| non_constant_p, overflow_p); |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* Try to fold expressions like |
| (struct S *) (&a[0].D.2378 + 12) |
| into |
| &MEM <struct T> [(void *)&a + 12B] |
| This is something normally done by gimple_fold_stmt_to_constant_1 |
| on GIMPLE, but is undesirable on GENERIC if we are e.g. going to |
| dereference the address because some details are lost. |
| For pointer comparisons we want such folding though so that |
| match.pd address_compare optimization works. */ |
| |
| static tree |
| cxx_maybe_fold_addr_pointer_plus (tree t) |
| { |
| while (CONVERT_EXPR_P (t) |
| && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (t, 0)))) |
| t = TREE_OPERAND (t, 0); |
| if (TREE_CODE (t) != POINTER_PLUS_EXPR) |
| return NULL_TREE; |
| tree op0 = TREE_OPERAND (t, 0); |
| tree op1 = TREE_OPERAND (t, 1); |
| if (TREE_CODE (op1) != INTEGER_CST) |
| return NULL_TREE; |
| while (CONVERT_EXPR_P (op0) |
| && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (op0, 0)))) |
| op0 = TREE_OPERAND (op0, 0); |
| if (TREE_CODE (op0) != ADDR_EXPR) |
| return NULL_TREE; |
| op1 = fold_convert (ptr_type_node, op1); |
| tree r = fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (op0)), op0, op1); |
| return build1_loc (EXPR_LOCATION (t), ADDR_EXPR, TREE_TYPE (op0), r); |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Like cxx_eval_unary_expression, except for binary expressions. */ |
| |
| static tree |
| cxx_eval_binary_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree r = NULL_TREE; |
| tree orig_lhs = TREE_OPERAND (t, 0); |
| tree orig_rhs = TREE_OPERAND (t, 1); |
| tree lhs, rhs; |
| lhs = cxx_eval_constant_expression (ctx, orig_lhs, vc_prvalue, |
| non_constant_p, overflow_p); |
| /* Don't VERIFY_CONSTANT here, it's unnecessary and will break pointer |
| subtraction. */ |
| if (*non_constant_p) |
| return t; |
| rhs = cxx_eval_constant_expression (ctx, orig_rhs, vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| |
| location_t loc = EXPR_LOCATION (t); |
| enum tree_code code = TREE_CODE (t); |
| tree type = TREE_TYPE (t); |
| |
| if (code == EQ_EXPR || code == NE_EXPR) |
| { |
| bool is_code_eq = (code == EQ_EXPR); |
| |
| if (TREE_CODE (lhs) == PTRMEM_CST |
| && TREE_CODE (rhs) == PTRMEM_CST) |
| { |
| tree lmem = PTRMEM_CST_MEMBER (lhs); |
| tree rmem = PTRMEM_CST_MEMBER (rhs); |
| bool eq; |
| if (TREE_CODE (lmem) == TREE_CODE (rmem) |
| && TREE_CODE (lmem) == FIELD_DECL |
| && TREE_CODE (DECL_CONTEXT (lmem)) == UNION_TYPE |
| && same_type_p (DECL_CONTEXT (lmem), |
| DECL_CONTEXT (rmem))) |
| /* If both refer to (possibly different) members of the same union |
| (12.3), they compare equal. */ |
| eq = true; |
| else |
| eq = cp_tree_equal (lhs, rhs); |
| r = constant_boolean_node (eq == is_code_eq, type); |
| } |
| else if ((TREE_CODE (lhs) == PTRMEM_CST |
| || TREE_CODE (rhs) == PTRMEM_CST) |
| && (null_member_pointer_value_p (lhs) |
| || null_member_pointer_value_p (rhs))) |
| r = constant_boolean_node (!is_code_eq, type); |
| else if (TREE_CODE (lhs) == PTRMEM_CST) |
| lhs = cplus_expand_constant (lhs); |
| else if (TREE_CODE (rhs) == PTRMEM_CST) |
| rhs = cplus_expand_constant (rhs); |
| } |
| if (r == NULL_TREE |
| && TREE_CODE_CLASS (code) == tcc_comparison |
| && POINTER_TYPE_P (TREE_TYPE (lhs))) |
| { |
| if (tree lhso = cxx_maybe_fold_addr_pointer_plus (lhs)) |
| lhs = fold_convert (TREE_TYPE (lhs), lhso); |
| if (tree rhso = cxx_maybe_fold_addr_pointer_plus (rhs)) |
| rhs = fold_convert (TREE_TYPE (rhs), rhso); |
| } |
| if (code == POINTER_PLUS_EXPR && !*non_constant_p |
| && integer_zerop (lhs) && !integer_zerop (rhs)) |
| { |
| if (!ctx->quiet) |
| error ("arithmetic involving a null pointer in %qE", lhs); |
| *non_constant_p = true; |
| return t; |
| } |
| else if (code == POINTER_PLUS_EXPR) |
| r = cxx_fold_pointer_plus_expression (ctx, t, lhs, rhs, non_constant_p, |
| overflow_p); |
| else if (code == SPACESHIP_EXPR) |
| { |
| r = genericize_spaceship (loc, type, lhs, rhs); |
| return cxx_eval_constant_expression (ctx, r, lval, non_constant_p, |
| overflow_p); |
| } |
| |
| if (r == NULL_TREE) |
| { |
| if (ctx->manifestly_const_eval |
| && (flag_constexpr_fp_except |
| || TREE_CODE (type) != REAL_TYPE)) |
| { |
| auto ofcc = make_temp_override (folding_cxx_constexpr, true); |
| r = fold_binary_initializer_loc (loc, code, type, lhs, rhs); |
| } |
| else |
| r = fold_binary_loc (loc, code, type, lhs, rhs); |
| } |
| |
| if (r == NULL_TREE |
| && (code == LSHIFT_EXPR || code == RSHIFT_EXPR) |
| && TREE_CODE (lhs) == INTEGER_CST |
| && TREE_CODE (rhs) == INTEGER_CST |
| && wi::neg_p (wi::to_wide (rhs))) |
| { |
| /* For diagnostics and -fpermissive emulate previous behavior of |
| handling shifts by negative amount. */ |
| tree nrhs = const_unop (NEGATE_EXPR, TREE_TYPE (rhs), rhs); |
| if (nrhs) |
| r = fold_binary_loc (loc, |
| code == LSHIFT_EXPR ? RSHIFT_EXPR : LSHIFT_EXPR, |
| type, lhs, nrhs); |
| } |
| |
| if (r == NULL_TREE) |
| { |
| if (lhs == orig_lhs && rhs == orig_rhs) |
| r = t; |
| else |
| r = build2_loc (loc, code, type, lhs, rhs); |
| } |
| else if (cxx_eval_check_shift_p (loc, ctx, code, type, lhs, rhs)) |
| *non_constant_p = true; |
| /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
| a local array in a constexpr function. */ |
| bool ptr = INDIRECT_TYPE_P (TREE_TYPE (lhs)); |
| if (!ptr) |
| VERIFY_CONSTANT (r); |
| return r; |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to evaluate condition expressions. Dead branches are not |
| looked into. */ |
| |
| static tree |
| cxx_eval_conditional_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p, |
| tree *jump_target) |
| { |
| tree val = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (val); |
| if (TREE_CODE (t) == IF_STMT && IF_STMT_CONSTEVAL_P (t)) |
| { |
| /* Evaluate the condition as if it was |
| if (__builtin_is_constant_evaluated ()), i.e. defer it if not |
| ctx->manifestly_const_eval (as sometimes we try to constant evaluate |
| without manifestly_const_eval even expressions or parts thereof which |
| will later be manifestly const_eval evaluated), otherwise fold it to |
| true. */ |
| if (ctx->manifestly_const_eval) |
| val = boolean_true_node; |
| else |
| { |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| /* Don't VERIFY_CONSTANT the other operands. */ |
| if (integer_zerop (val)) |
| val = TREE_OPERAND (t, 2); |
| else |
| val = TREE_OPERAND (t, 1); |
| if (TREE_CODE (t) == IF_STMT && !val) |
| val = void_node; |
| /* A TARGET_EXPR may be nested inside another TARGET_EXPR, but still |
| serve as the initializer for the same object as the outer TARGET_EXPR, |
| as in |
| A a = true ? A{} : A{}; |
| so strip the inner TARGET_EXPR so we don't materialize a temporary. */ |
| if (TREE_CODE (val) == TARGET_EXPR) |
| val = TARGET_EXPR_INITIAL (val); |
| return cxx_eval_constant_expression (ctx, val, lval, non_constant_p, |
| overflow_p, jump_target); |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to evaluate vector condition expressions. Unlike |
| cxx_eval_conditional_expression, VEC_COND_EXPR acts like a normal |
| ternary arithmetics operation, where all 3 arguments have to be |
| evaluated as constants and then folding computes the result from |
| them. */ |
| |
| static tree |
| cxx_eval_vector_conditional_expression (const constexpr_ctx *ctx, tree t, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree arg1 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (arg1); |
| tree arg2 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
| vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (arg2); |
| tree arg3 = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 2), |
| vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (arg3); |
| location_t loc = EXPR_LOCATION (t); |
| tree type = TREE_TYPE (t); |
| tree r = fold_ternary_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); |
| if (r == NULL_TREE) |
| { |
| if (arg1 == TREE_OPERAND (t, 0) |
| && arg2 == TREE_OPERAND (t, 1) |
| && arg3 == TREE_OPERAND (t, 2)) |
| r = t; |
| else |
| r = build3_loc (loc, VEC_COND_EXPR, type, arg1, arg2, arg3); |
| } |
| VERIFY_CONSTANT (r); |
| return r; |
| } |
| |
| /* Returns less than, equal to, or greater than zero if KEY is found to be |
| less than, to match, or to be greater than the constructor_elt's INDEX. */ |
| |
| static int |
| array_index_cmp (tree key, tree index) |
| { |
| gcc_assert (TREE_CODE (key) == INTEGER_CST); |
| |
| switch (TREE_CODE (index)) |
| { |
| case INTEGER_CST: |
| return tree_int_cst_compare (key, index); |
| case RANGE_EXPR: |
| { |
| tree lo = TREE_OPERAND (index, 0); |
| tree hi = TREE_OPERAND (index, 1); |
| if (tree_int_cst_lt (key, lo)) |
| return -1; |
| else if (tree_int_cst_lt (hi, key)) |
| return 1; |
| else |
| return 0; |
| } |
| default: |
| gcc_unreachable (); |
| } |
| } |
| |
| /* Returns the index of the constructor_elt of ARY which matches DINDEX, or -1 |
| if none. If INSERT is true, insert a matching element rather than fail. */ |
| |
| static HOST_WIDE_INT |
| find_array_ctor_elt (tree ary, tree dindex, bool insert) |
| { |
| if (tree_int_cst_sgn (dindex) < 0) |
| return -1; |
| |
| unsigned HOST_WIDE_INT i = tree_to_uhwi (dindex); |
| vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ary); |
| unsigned HOST_WIDE_INT len = vec_safe_length (elts); |
| |
| unsigned HOST_WIDE_INT end = len; |
| unsigned HOST_WIDE_INT begin = 0; |
| |
| /* If the last element of the CONSTRUCTOR has its own index, we can assume |
| that the same is true of the other elements and index directly. */ |
| if (end > 0) |
| { |
| tree cindex = (*elts)[end - 1].index; |
| if (cindex == NULL_TREE) |
| { |
| /* Verify that if the last index is missing, all indexes |
| are missing. */ |
| if (flag_checking) |
| for (unsigned int j = 0; j < len - 1; ++j) |
| gcc_assert ((*elts)[j].index == NULL_TREE); |
| if (i < end) |
| return i; |
| else |
| { |
| begin = end; |
| if (i == end) |
| /* If the element is to be added right at the end, |
| make sure it is added with cleared index too. */ |
| dindex = NULL_TREE; |
| else if (insert) |
| /* Otherwise, in order not to break the assumption |
| that CONSTRUCTOR either has all indexes or none, |
| we need to add indexes to all elements. */ |
| for (unsigned int j = 0; j < len; ++j) |
| (*elts)[j].index = build_int_cst (TREE_TYPE (dindex), j); |
| } |
| } |
| else if (TREE_CODE (cindex) == INTEGER_CST |
| && compare_tree_int (cindex, end - 1) == 0) |
| { |
| if (i < end) |
| return i; |
| else |
| begin = end; |
| } |
| } |
| |
| /* Otherwise, find a matching index by means of a binary search. */ |
| while (begin != end) |
| { |
| unsigned HOST_WIDE_INT middle = (begin + end) / 2; |
| constructor_elt &elt = (*elts)[middle]; |
| tree idx = elt.index; |
| |
| int cmp = array_index_cmp (dindex, idx); |
| if (cmp < 0) |
| end = middle; |
| else if (cmp > 0) |
| begin = middle + 1; |
| else |
| { |
| if (insert && TREE_CODE (idx) == RANGE_EXPR) |
| { |
| /* We need to split the range. */ |
| constructor_elt e; |
| tree lo = TREE_OPERAND (idx, 0); |
| tree hi = TREE_OPERAND (idx, 1); |
| tree value = elt.value; |
| dindex = fold_convert (sizetype, dindex); |
| if (tree_int_cst_lt (lo, dindex)) |
| { |
| /* There are still some lower elts; shorten the range. */ |
| tree new_hi = int_const_binop (MINUS_EXPR, dindex, |
| size_one_node); |
| if (tree_int_cst_equal (lo, new_hi)) |
| /* Only one element left, no longer a range. */ |
| elt.index = lo; |
| else |
| TREE_OPERAND (idx, 1) = new_hi; |
| /* Append the element we want to insert. */ |
| ++middle; |
| e.index = dindex; |
| e.value = unshare_constructor (value); |
| vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); |
| } |
| else |
| /* No lower elts, the range elt is now ours. */ |
| elt.index = dindex; |
| |
| if (tree_int_cst_lt (dindex, hi)) |
| { |
| /* There are still some higher elts; append a range. */ |
| tree new_lo = int_const_binop (PLUS_EXPR, dindex, |
| size_one_node); |
| if (tree_int_cst_equal (new_lo, hi)) |
| e.index = hi; |
| else |
| e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); |
| e.value = unshare_constructor (value); |
| vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle + 1, e); |
| } |
| } |
| return middle; |
| } |
| } |
| |
| if (insert) |
| { |
| constructor_elt e = { dindex, NULL_TREE }; |
| vec_safe_insert (CONSTRUCTOR_ELTS (ary), end, e); |
| return end; |
| } |
| |
| return -1; |
| } |
| |
| /* Return a pointer to the constructor_elt of CTOR which matches INDEX. If no |
| matching constructor_elt exists, then add one to CTOR. |
| |
| As an optimization, if POS_HINT is non-negative then it is used as a guess |
| for the (integer) index of the matching constructor_elt within CTOR. */ |
| |
| static constructor_elt * |
| get_or_insert_ctor_field (tree ctor, tree index, int pos_hint = -1) |
| { |
| /* Check the hint first. */ |
| if (pos_hint >= 0 && (unsigned)pos_hint < CONSTRUCTOR_NELTS (ctor) |
| && CONSTRUCTOR_ELT (ctor, pos_hint)->index == index) |
| return CONSTRUCTOR_ELT (ctor, pos_hint); |
| |
| tree type = TREE_TYPE (ctor); |
| if (TREE_CODE (type) == VECTOR_TYPE && index == NULL_TREE) |
| { |
| CONSTRUCTOR_APPEND_ELT (CONSTRUCTOR_ELTS (ctor), index, NULL_TREE); |
| return &CONSTRUCTOR_ELTS (ctor)->last(); |
| } |
| else if (TREE_CODE (type) == ARRAY_TYPE || TREE_CODE (type) == VECTOR_TYPE) |
| { |
| if (TREE_CODE (index) == RANGE_EXPR) |
| { |
| /* Support for RANGE_EXPR index lookups is currently limited to |
| accessing an existing element via POS_HINT, or appending a new |
| element to the end of CTOR. ??? Support for other access |
| patterns may also be needed. */ |
| vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ctor); |
| if (vec_safe_length (elts)) |
| { |
| tree lo = TREE_OPERAND (index, 0); |
| gcc_assert (array_index_cmp (elts->last().index, lo) < 0); |
| } |
| CONSTRUCTOR_APPEND_ELT (elts, index, NULL_TREE); |
| return &elts->last(); |
| } |
| |
| HOST_WIDE_INT i = find_array_ctor_elt (ctor, index, /*insert*/true); |
| gcc_assert (i >= 0); |
| constructor_elt *cep = CONSTRUCTOR_ELT (ctor, i); |
| gcc_assert (cep->index == NULL_TREE |
| || TREE_CODE (cep->index) != RANGE_EXPR); |
| return cep; |
| } |
| else |
| { |
| gcc_assert (TREE_CODE (index) == FIELD_DECL |
| && (same_type_ignoring_top_level_qualifiers_p |
| (DECL_CONTEXT (index), TREE_TYPE (ctor)))); |
| |
| /* We must keep the CONSTRUCTOR's ELTS in FIELD order. |
| Usually we meet initializers in that order, but it is |
| possible for base types to be placed not in program |
| order. */ |
| tree fields = TYPE_FIELDS (DECL_CONTEXT (index)); |
| unsigned HOST_WIDE_INT idx = 0; |
| constructor_elt *cep = NULL; |
| |
| /* Check if we're changing the active member of a union. */ |
| if (TREE_CODE (type) == UNION_TYPE && CONSTRUCTOR_NELTS (ctor) |
| && CONSTRUCTOR_ELT (ctor, 0)->index != index) |
| vec_safe_truncate (CONSTRUCTOR_ELTS (ctor), 0); |
| /* If the bit offset of INDEX is larger than that of the last |
| constructor_elt, then we can just immediately append a new |
| constructor_elt to the end of CTOR. */ |
| else if (CONSTRUCTOR_NELTS (ctor) |
| && tree_int_cst_compare (bit_position (index), |
| bit_position (CONSTRUCTOR_ELTS (ctor) |
| ->last().index)) > 0) |
| { |
| idx = CONSTRUCTOR_NELTS (ctor); |
| goto insert; |
| } |
| |
| /* Otherwise, we need to iterate over CTOR to find or insert INDEX |
| appropriately. */ |
| |
| for (; vec_safe_iterate (CONSTRUCTOR_ELTS (ctor), idx, &cep); |
| idx++, fields = DECL_CHAIN (fields)) |
| { |
| if (index == cep->index) |
| goto found; |
| |
| /* The field we're initializing must be on the field |
| list. Look to see if it is present before the |
| field the current ELT initializes. */ |
| for (; fields != cep->index; fields = DECL_CHAIN (fields)) |
| if (index == fields) |
| goto insert; |
| } |
| /* We fell off the end of the CONSTRUCTOR, so insert a new |
| entry at the end. */ |
| |
| insert: |
| { |
| constructor_elt ce = { index, NULL_TREE }; |
| |
| vec_safe_insert (CONSTRUCTOR_ELTS (ctor), idx, ce); |
| cep = CONSTRUCTOR_ELT (ctor, idx); |
| } |
| found:; |
| |
| return cep; |
| } |
| } |
| |
| /* Under the control of CTX, issue a detailed diagnostic for |
| an out-of-bounds subscript INDEX into the expression ARRAY. */ |
| |
| static void |
| diag_array_subscript (location_t loc, const constexpr_ctx *ctx, tree array, tree index) |
| { |
| if (!ctx->quiet) |
| { |
| tree arraytype = TREE_TYPE (array); |
| |
| /* Convert the unsigned array subscript to a signed integer to avoid |
| printing huge numbers for small negative values. */ |
| tree sidx = fold_convert (ssizetype, index); |
| STRIP_ANY_LOCATION_WRAPPER (array); |
| if (DECL_P (array)) |
| { |
| if (TYPE_DOMAIN (arraytype)) |
| error_at (loc, "array subscript value %qE is outside the bounds " |
| "of array %qD of type %qT", sidx, array, arraytype); |
| else |
| error_at (loc, "nonzero array subscript %qE is used with array %qD of " |
| "type %qT with unknown bounds", sidx, array, arraytype); |
| inform (DECL_SOURCE_LOCATION (array), "declared here"); |
| } |
| else if (TYPE_DOMAIN (arraytype)) |
| error_at (loc, "array subscript value %qE is outside the bounds " |
| "of array type %qT", sidx, arraytype); |
| else |
| error_at (loc, "nonzero array subscript %qE is used with array of type %qT " |
| "with unknown bounds", sidx, arraytype); |
| } |
| } |
| |
| /* Return the number of elements for TYPE (which is an ARRAY_TYPE or |
| a VECTOR_TYPE). */ |
| |
| static tree |
| get_array_or_vector_nelts (const constexpr_ctx *ctx, tree type, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree nelts; |
| if (TREE_CODE (type) == ARRAY_TYPE) |
| { |
| if (TYPE_DOMAIN (type)) |
| nelts = array_type_nelts_top (type); |
| else |
| nelts = size_zero_node; |
| } |
| else if (VECTOR_TYPE_P (type)) |
| nelts = size_int (TYPE_VECTOR_SUBPARTS (type)); |
| else |
| gcc_unreachable (); |
| |
| /* For VLAs, the number of elements won't be an integer constant. */ |
| nelts = cxx_eval_constant_expression (ctx, nelts, vc_prvalue, |
| non_constant_p, overflow_p); |
| return nelts; |
| } |
| |
| /* Extract element INDEX consisting of CHARS_PER_ELT chars from |
| STRING_CST STRING. */ |
| |
| static tree |
| extract_string_elt (tree string, unsigned chars_per_elt, unsigned index) |
| { |
| tree type = cv_unqualified (TREE_TYPE (TREE_TYPE (string))); |
| tree r; |
| |
| if (chars_per_elt == 1) |
| r = build_int_cst (type, TREE_STRING_POINTER (string)[index]); |
| else |
| { |
| const unsigned char *ptr |
| = ((const unsigned char *)TREE_STRING_POINTER (string) |
| + index * chars_per_elt); |
| r = native_interpret_expr (type, ptr, chars_per_elt); |
| } |
| return r; |
| } |
| |
| /* Subroutine of cxx_eval_array_reference. T is an ARRAY_REF; evaluate the |
| subscript, diagnose any problems with it, and return the result. */ |
| |
| static tree |
| eval_and_check_array_index (const constexpr_ctx *ctx, |
| tree t, bool allow_one_past, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| location_t loc = cp_expr_loc_or_input_loc (t); |
| tree ary = TREE_OPERAND (t, 0); |
| t = TREE_OPERAND (t, 1); |
| tree index = cxx_eval_constant_expression (ctx, t, vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (index); |
| |
| if (!tree_fits_shwi_p (index) |
| || tree_int_cst_sgn (index) < 0) |
| { |
| diag_array_subscript (loc, ctx, ary, index); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| tree nelts = get_array_or_vector_nelts (ctx, TREE_TYPE (ary), non_constant_p, |
| overflow_p); |
| VERIFY_CONSTANT (nelts); |
| if (allow_one_past |
| ? !tree_int_cst_le (index, nelts) |
| : !tree_int_cst_lt (index, nelts)) |
| { |
| diag_array_subscript (loc, ctx, ary, index); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| return index; |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to reduce a reference to an array slot. */ |
| |
| static tree |
| cxx_eval_array_reference (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree oldary = TREE_OPERAND (t, 0); |
| tree ary = cxx_eval_constant_expression (ctx, oldary, |
| lval, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| if (!lval |
| && TREE_CODE (ary) == VIEW_CONVERT_EXPR |
| && VECTOR_TYPE_P (TREE_TYPE (TREE_OPERAND (ary, 0))) |
| && TREE_TYPE (t) == TREE_TYPE (TREE_TYPE (TREE_OPERAND (ary, 0)))) |
| ary = TREE_OPERAND (ary, 0); |
| |
| tree oldidx = TREE_OPERAND (t, 1); |
| tree index = eval_and_check_array_index (ctx, t, lval, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| |
| if (lval && ary == oldary && index == oldidx) |
| return t; |
| else if (lval == vc_discard) |
| return t; |
| else if (lval) |
| return build4 (ARRAY_REF, TREE_TYPE (t), ary, index, NULL, NULL); |
| |
| unsigned len = 0, elem_nchars = 1; |
| tree elem_type = TREE_TYPE (TREE_TYPE (ary)); |
| if (TREE_CODE (ary) == CONSTRUCTOR) |
| len = CONSTRUCTOR_NELTS (ary); |
| else if (TREE_CODE (ary) == STRING_CST) |
| { |
| elem_nchars = (TYPE_PRECISION (elem_type) |
| / TYPE_PRECISION (char_type_node)); |
| len = (unsigned) TREE_STRING_LENGTH (ary) / elem_nchars; |
| } |
| else if (TREE_CODE (ary) == VECTOR_CST) |
| /* We don't create variable-length VECTOR_CSTs. */ |
| len = VECTOR_CST_NELTS (ary).to_constant (); |
| else |
| { |
| /* We can't do anything with other tree codes, so use |
| VERIFY_CONSTANT to complain and fail. */ |
| VERIFY_CONSTANT (ary); |
| gcc_unreachable (); |
| } |
| |
| bool found; |
| HOST_WIDE_INT i = 0; |
| if (TREE_CODE (ary) == CONSTRUCTOR) |
| { |
| HOST_WIDE_INT ix = find_array_ctor_elt (ary, index); |
| found = (ix >= 0); |
| if (found) |
| i = ix; |
| } |
| else |
| { |
| i = tree_to_shwi (index); |
| found = (i < len); |
| } |
| |
| if (found) |
| { |
| tree r; |
| if (TREE_CODE (ary) == CONSTRUCTOR) |
| r = (*CONSTRUCTOR_ELTS (ary))[i].value; |
| else if (TREE_CODE (ary) == VECTOR_CST) |
| r = VECTOR_CST_ELT (ary, i); |
| else |
| r = extract_string_elt (ary, elem_nchars, i); |
| |
| if (r) |
| /* Don't VERIFY_CONSTANT here. */ |
| return r; |
| |
| /* Otherwise the element doesn't have a value yet. */ |
| } |
| |
| /* Not found. */ |
| |
| if (TREE_CODE (ary) == CONSTRUCTOR |
| && CONSTRUCTOR_NO_CLEARING (ary)) |
| { |
| /* 'ary' is part of the aggregate initializer we're currently |
| building; if there's no initializer for this element yet, |
| that's an error. */ |
| if (!ctx->quiet) |
| error ("accessing uninitialized array element"); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* If it's within the array bounds but doesn't have an explicit |
| initializer, it's initialized from {}. But use build_value_init |
| directly for non-aggregates to avoid creating a garbage CONSTRUCTOR. */ |
| tree val; |
| constexpr_ctx new_ctx; |
| if (is_really_empty_class (elem_type, /*ignore_vptr*/false)) |
| return build_constructor (elem_type, NULL); |
| else if (CP_AGGREGATE_TYPE_P (elem_type)) |
| { |
| tree empty_ctor = build_constructor (init_list_type_node, NULL); |
| val = digest_init (elem_type, empty_ctor, tf_warning_or_error); |
| } |
| else |
| val = build_value_init (elem_type, tf_warning_or_error); |
| |
| if (!SCALAR_TYPE_P (elem_type)) |
| { |
| new_ctx = *ctx; |
| new_ctx.ctor = build_constructor (elem_type, NULL); |
| ctx = &new_ctx; |
| } |
| t = cxx_eval_constant_expression (ctx, val, lval, non_constant_p, |
| overflow_p); |
| if (!SCALAR_TYPE_P (elem_type) && t != ctx->ctor) |
| free_constructor (ctx->ctor); |
| return t; |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to reduce a field access of a value of class type. */ |
| |
| static tree |
| cxx_eval_component_reference (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| unsigned HOST_WIDE_INT i; |
| tree field; |
| tree value; |
| tree part = TREE_OPERAND (t, 1); |
| tree orig_whole = TREE_OPERAND (t, 0); |
| tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
| lval, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| if (INDIRECT_REF_P (whole) |
| && integer_zerop (TREE_OPERAND (whole, 0))) |
| { |
| if (!ctx->quiet) |
| error ("dereferencing a null pointer in %qE", orig_whole); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| if (TREE_CODE (whole) == PTRMEM_CST) |
| whole = cplus_expand_constant (whole); |
| if (whole == orig_whole) |
| return t; |
| if (lval == vc_discard) |
| return t; |
| if (lval) |
| return fold_build3 (COMPONENT_REF, TREE_TYPE (t), |
| whole, part, NULL_TREE); |
| /* Don't VERIFY_CONSTANT here; we only want to check that we got a |
| CONSTRUCTOR. */ |
| if (TREE_CODE (whole) != CONSTRUCTOR) |
| { |
| if (!ctx->quiet) |
| error ("%qE is not a constant expression", orig_whole); |
| *non_constant_p = true; |
| return t; |
| } |
| if ((cxx_dialect < cxx14 || CONSTRUCTOR_MUTABLE_POISON (whole)) |
| && DECL_MUTABLE_P (part)) |
| { |
| if (!ctx->quiet) |
| error ("mutable %qD is not usable in a constant expression", part); |
| *non_constant_p = true; |
| return t; |
| } |
| bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole)); |
| FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
| { |
| /* Use name match for PMF fields, as a variant will have a |
| different FIELD_DECL with a different type. */ |
| if (pmf ? DECL_NAME (field) == DECL_NAME (part) |
| : field == part) |
| { |
| if (value) |
| { |
| STRIP_ANY_LOCATION_WRAPPER (value); |
| return value; |
| } |
| else |
| /* We're in the middle of initializing it. */ |
| break; |
| } |
| } |
| if (TREE_CODE (TREE_TYPE (whole)) == UNION_TYPE |
| && CONSTRUCTOR_NELTS (whole) > 0) |
| { |
| /* DR 1188 says we don't have to deal with this. */ |
| if (!ctx->quiet) |
| { |
| constructor_elt *cep = CONSTRUCTOR_ELT (whole, 0); |
| if (cep->value == NULL_TREE) |
| error ("accessing uninitialized member %qD", part); |
| else |
| error ("accessing %qD member instead of initialized %qD member in " |
| "constant expression", part, cep->index); |
| } |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* We only create a CONSTRUCTOR for a subobject when we modify it, so empty |
| classes never get represented; throw together a value now. */ |
| if (is_really_empty_class (TREE_TYPE (t), /*ignore_vptr*/false)) |
| return build_constructor (TREE_TYPE (t), NULL); |
| |
| gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole))); |
| |
| if (CONSTRUCTOR_NO_CLEARING (whole)) |
| { |
| /* 'whole' is part of the aggregate initializer we're currently |
| building; if there's no initializer for this member yet, that's an |
| error. */ |
| if (!ctx->quiet) |
| error ("accessing uninitialized member %qD", part); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* If there's no explicit init for this field, it's value-initialized. */ |
| value = build_value_init (TREE_TYPE (t), tf_warning_or_error); |
| return cxx_eval_constant_expression (ctx, value, |
| lval, |
| non_constant_p, overflow_p); |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to reduce a field access of a value of class type that is |
| expressed as a BIT_FIELD_REF. */ |
| |
| static tree |
| cxx_eval_bit_field_ref (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree orig_whole = TREE_OPERAND (t, 0); |
| tree retval, fldval, utype, mask; |
| bool fld_seen = false; |
| HOST_WIDE_INT istart, isize; |
| tree whole = cxx_eval_constant_expression (ctx, orig_whole, |
| lval, |
| non_constant_p, overflow_p); |
| tree start, field, value; |
| unsigned HOST_WIDE_INT i; |
| |
| if (whole == orig_whole) |
| return t; |
| /* Don't VERIFY_CONSTANT here; we only want to check that we got a |
| CONSTRUCTOR. */ |
| if (!*non_constant_p |
| && TREE_CODE (whole) != VECTOR_CST |
| && TREE_CODE (whole) != CONSTRUCTOR) |
| { |
| if (!ctx->quiet) |
| error ("%qE is not a constant expression", orig_whole); |
| *non_constant_p = true; |
| } |
| if (*non_constant_p) |
| return t; |
| |
| if (TREE_CODE (whole) == VECTOR_CST || !INTEGRAL_TYPE_P (TREE_TYPE (t))) |
| { |
| if (tree r = fold_ternary (BIT_FIELD_REF, TREE_TYPE (t), whole, |
| TREE_OPERAND (t, 1), TREE_OPERAND (t, 2))) |
| return r; |
| if (!ctx->quiet) |
| error ("%qE is not a constant expression", orig_whole); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| start = TREE_OPERAND (t, 2); |
| istart = tree_to_shwi (start); |
| isize = tree_to_shwi (TREE_OPERAND (t, 1)); |
| utype = TREE_TYPE (t); |
| if (!TYPE_UNSIGNED (utype)) |
| utype = build_nonstandard_integer_type (TYPE_PRECISION (utype), 1); |
| retval = build_int_cst (utype, 0); |
| FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value) |
| { |
| tree bitpos = bit_position (field); |
| STRIP_ANY_LOCATION_WRAPPER (value); |
| if (bitpos == start && DECL_SIZE (field) == TREE_OPERAND (t, 1)) |
| return value; |
| if (TREE_CODE (TREE_TYPE (field)) == INTEGER_TYPE |
| && TREE_CODE (value) == INTEGER_CST |
| && tree_fits_shwi_p (bitpos) |
| && tree_fits_shwi_p (DECL_SIZE (field))) |
| { |
| HOST_WIDE_INT bit = tree_to_shwi (bitpos); |
| HOST_WIDE_INT sz = tree_to_shwi (DECL_SIZE (field)); |
| HOST_WIDE_INT shift; |
| if (bit >= istart && bit + sz <= istart + isize) |
| { |
| fldval = fold_convert (utype, value); |
| mask = build_int_cst_type (utype, -1); |
| mask = fold_build2 (LSHIFT_EXPR, utype, mask, |
| size_int (TYPE_PRECISION (utype) - sz)); |
| mask = fold_build2 (RSHIFT_EXPR, utype, mask, |
| size_int (TYPE_PRECISION (utype) - sz)); |
| fldval = fold_build2 (BIT_AND_EXPR, utype, fldval, mask); |
| shift = bit - istart; |
| if (BYTES_BIG_ENDIAN) |
| shift = TYPE_PRECISION (utype) - shift - sz; |
| fldval = fold_build2 (LSHIFT_EXPR, utype, fldval, |
| size_int (shift)); |
| retval = fold_build2 (BIT_IOR_EXPR, utype, retval, fldval); |
| fld_seen = true; |
| } |
| } |
| } |
| if (fld_seen) |
| return fold_convert (TREE_TYPE (t), retval); |
| gcc_unreachable (); |
| return error_mark_node; |
| } |
| |
| /* Helper for cxx_eval_bit_cast. |
| Check [bit.cast]/3 rules, bit_cast is constexpr only if the To and From |
| types and types of all subobjects have is_union_v<T>, is_pointer_v<T>, |
| is_member_pointer_v<T>, is_volatile_v<T> false and has no non-static |
| data members of reference type. */ |
| |
| static bool |
| check_bit_cast_type (const constexpr_ctx *ctx, location_t loc, tree type, |
| tree orig_type) |
| { |
| if (TREE_CODE (type) == UNION_TYPE) |
| { |
| if (!ctx->quiet) |
| { |
| if (type == orig_type) |
| error_at (loc, "%qs is not a constant expression because %qT is " |
| "a union type", "__builtin_bit_cast", type); |
| else |
| error_at (loc, "%qs is not a constant expression because %qT " |
| "contains a union type", "__builtin_bit_cast", |
| orig_type); |
| } |
| return true; |
| } |
| if (TREE_CODE (type) == POINTER_TYPE) |
| { |
| if (!ctx->quiet) |
| { |
| if (type == orig_type) |
| error_at (loc, "%qs is not a constant expression because %qT is " |
| "a pointer type", "__builtin_bit_cast", type); |
| else |
| error_at (loc, "%qs is not a constant expression because %qT " |
| "contains a pointer type", "__builtin_bit_cast", |
| orig_type); |
| } |
| return true; |
| } |
| if (TREE_CODE (type) == REFERENCE_TYPE) |
| { |
| if (!ctx->quiet) |
| { |
| if (type == orig_type) |
| error_at (loc, "%qs is not a constant expression because %qT is " |
| "a reference type", "__builtin_bit_cast", type); |
| else |
| error_at (loc, "%qs is not a constant expression because %qT " |
| "contains a reference type", "__builtin_bit_cast", |
| orig_type); |
| } |
| return true; |
| } |
| if (TYPE_PTRMEM_P (type)) |
| { |
| if (!ctx->quiet) |
| { |
| if (type == orig_type) |
| error_at (loc, "%qs is not a constant expression because %qT is " |
| "a pointer to member type", "__builtin_bit_cast", |
| type); |
| else |
| error_at (loc, "%qs is not a constant expression because %qT " |
| "contains a pointer to member type", |
| "__builtin_bit_cast", orig_type); |
| } |
| return true; |
| } |
| if (TYPE_VOLATILE (type)) |
| { |
| if (!ctx->quiet) |
| { |
| if (type == orig_type) |
| error_at (loc, "%qs is not a constant expression because %qT is " |
| "volatile", "__builtin_bit_cast", type); |
| else |
| error_at (loc, "%qs is not a constant expression because %qT " |
| "contains a volatile subobject", |
| "__builtin_bit_cast", orig_type); |
| } |
| return true; |
| } |
| if (TREE_CODE (type) == RECORD_TYPE) |
| for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field)) |
| if (TREE_CODE (field) == FIELD_DECL |
| && check_bit_cast_type (ctx, loc, TREE_TYPE (field), orig_type)) |
| return true; |
| return false; |
| } |
| |
| /* Helper function for cxx_eval_bit_cast. For unsigned char or |
| std::byte members of CONSTRUCTOR (recursively) if they contain |
| some indeterminate bits (as set in MASK), remove the ctor elts, |
| mark the CONSTRUCTOR as CONSTRUCTOR_NO_CLEARING and clear the |
| bits in MASK. */ |
| |
| static void |
| clear_uchar_or_std_byte_in_mask (location_t loc, tree t, unsigned char *mask) |
| { |
| if (TREE_CODE (t) != CONSTRUCTOR) |
| return; |
| |
| unsigned i, j = 0; |
| tree index, value; |
| FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), i, index, value) |
| { |
| tree type = TREE_TYPE (value); |
| if (TREE_CODE (TREE_TYPE (t)) != ARRAY_TYPE |
| && DECL_BIT_FIELD_TYPE (index) != NULL_TREE) |
| { |
| if (is_byte_access_type_not_plain_char (DECL_BIT_FIELD_TYPE (index))) |
| { |
| HOST_WIDE_INT fldsz = TYPE_PRECISION (TREE_TYPE (index)); |
| gcc_assert (fldsz != 0); |
| HOST_WIDE_INT pos = int_byte_position (index); |
| HOST_WIDE_INT bpos |
| = tree_to_uhwi (DECL_FIELD_BIT_OFFSET (index)); |
| bpos %= BITS_PER_UNIT; |
| HOST_WIDE_INT end |
| = ROUND_UP (bpos + fldsz, BITS_PER_UNIT) / BITS_PER_UNIT; |
| gcc_assert (end == 1 || end == 2); |
| unsigned char *p = mask + pos; |
| unsigned char mask_save[2]; |
| mask_save[0] = mask[pos]; |
| mask_save[1] = end == 2 ? mask[pos + 1] : 0; |
| if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN) |
| sorry_at (loc, "PDP11 bit-field handling unsupported" |
| " in %qs", "__builtin_bit_cast"); |
| else if (BYTES_BIG_ENDIAN) |
| { |
| /* Big endian. */ |
| if (bpos + fldsz <= BITS_PER_UNIT) |
| *p &= ~(((1 << fldsz) - 1) |
| << (BITS_PER_UNIT - bpos - fldsz)); |
| else |
| { |
| gcc_assert (bpos); |
| *p &= ~(((1U << BITS_PER_UNIT) - 1) >> bpos); |
| p++; |
| fldsz -= BITS_PER_UNIT - bpos; |
| gcc_assert (fldsz && fldsz < BITS_PER_UNIT); |
| *p &= ((1U << BITS_PER_UNIT) - 1) >> fldsz; |
| } |
| } |
| else |
| { |
| /* Little endian. */ |
| if (bpos + fldsz <= BITS_PER_UNIT) |
| *p &= ~(((1 << fldsz) - 1) << bpos); |
| else |
| { |
| gcc_assert (bpos); |
| *p &= ~(((1 << BITS_PER_UNIT) - 1) << bpos); |
| p++; |
| fldsz -= BITS_PER_UNIT - bpos; |
| gcc_assert (fldsz && fldsz < BITS_PER_UNIT); |
| *p &= ~((1 << fldsz) - 1); |
| } |
| } |
| if (mask_save[0] != mask[pos] |
| || (end == 2 && mask_save[1] != mask[pos + 1])) |
| { |
| CONSTRUCTOR_NO_CLEARING (t) = 1; |
| continue; |
| } |
| } |
| } |
| else if (is_byte_access_type_not_plain_char (type)) |
| { |
| HOST_WIDE_INT pos; |
| if (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE) |
| pos = tree_to_shwi (index); |
| else |
| pos = int_byte_position (index); |
| if (mask[pos]) |
| { |
| CONSTRUCTOR_NO_CLEARING (t) = 1; |
| mask[pos] = 0; |
| continue; |
| } |
| } |
| if (TREE_CODE (value) == CONSTRUCTOR) |
| { |
| HOST_WIDE_INT pos; |
| if (TREE_CODE (TREE_TYPE (t)) == ARRAY_TYPE) |
| pos = tree_to_shwi (index) |
| * tree_to_shwi (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (t)))); |
| else |
| pos = int_byte_position (index); |
| clear_uchar_or_std_byte_in_mask (loc, value, mask + pos); |
| } |
| if (i != j) |
| { |
| CONSTRUCTOR_ELT (t, j)->index = index; |
| CONSTRUCTOR_ELT (t, j)->value = value; |
| } |
| ++j; |
| } |
| if (CONSTRUCTOR_NELTS (t) != j) |
| vec_safe_truncate (CONSTRUCTOR_ELTS (t), j); |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Attempt to evaluate a BIT_CAST_EXPR. */ |
| |
| static tree |
| cxx_eval_bit_cast (const constexpr_ctx *ctx, tree t, bool *non_constant_p, |
| bool *overflow_p) |
| { |
| if (check_bit_cast_type (ctx, EXPR_LOCATION (t), TREE_TYPE (t), |
| TREE_TYPE (t)) |
| || check_bit_cast_type (ctx, cp_expr_loc_or_loc (TREE_OPERAND (t, 0), |
| EXPR_LOCATION (t)), |
| TREE_TYPE (TREE_OPERAND (t, 0)), |
| TREE_TYPE (TREE_OPERAND (t, 0)))) |
| { |
| *non_constant_p = true; |
| return t; |
| } |
| |
| tree op = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| |
| location_t loc = EXPR_LOCATION (t); |
| if (BITS_PER_UNIT != 8 || CHAR_BIT != 8) |
| { |
| if (!ctx->quiet) |
| sorry_at (loc, "%qs cannot be constant evaluated on the target", |
| "__builtin_bit_cast"); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| if (!tree_fits_shwi_p (TYPE_SIZE_UNIT (TREE_TYPE (t)))) |
| { |
| if (!ctx->quiet) |
| sorry_at (loc, "%qs cannot be constant evaluated because the " |
| "type is too large", "__builtin_bit_cast"); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| HOST_WIDE_INT len = tree_to_shwi (TYPE_SIZE_UNIT (TREE_TYPE (t))); |
| if (len < 0 || (int) len != len) |
| { |
| if (!ctx->quiet) |
| sorry_at (loc, "%qs cannot be constant evaluated because the " |
| "type is too large", "__builtin_bit_cast"); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| unsigned char buf[64]; |
| unsigned char *ptr, *mask; |
| size_t alen = (size_t) len * 2; |
| if (alen <= sizeof (buf)) |
| ptr = buf; |
| else |
| ptr = XNEWVEC (unsigned char, alen); |
| mask = ptr + (size_t) len; |
| /* At the beginning consider everything indeterminate. */ |
| memset (mask, ~0, (size_t) len); |
| |
| if (native_encode_initializer (op, ptr, len, 0, mask) != len) |
| { |
| if (!ctx->quiet) |
| sorry_at (loc, "%qs cannot be constant evaluated because the " |
| "argument cannot be encoded", "__builtin_bit_cast"); |
| *non_constant_p = true; |
| if (ptr != buf) |
| XDELETE (ptr); |
| return t; |
| } |
| |
| tree r = NULL_TREE; |
| if (can_native_interpret_type_p (TREE_TYPE (t))) |
| { |
| r = native_interpret_expr (TREE_TYPE (t), ptr, len); |
| if (is_byte_access_type_not_plain_char (TREE_TYPE (t))) |
| { |
| gcc_assert (len == 1); |
| if (mask[0]) |
| { |
| memset (mask, 0, len); |
| r = build_constructor (TREE_TYPE (r), NULL); |
| CONSTRUCTOR_NO_CLEARING (r) = 1; |
| } |
| } |
| } |
| else if (TREE_CODE (TREE_TYPE (t)) == RECORD_TYPE) |
| { |
| r = native_interpret_aggregate (TREE_TYPE (t), ptr, 0, len); |
| if (r != NULL_TREE) |
| { |
| clear_type_padding_in_mask (TREE_TYPE (t), mask); |
| clear_uchar_or_std_byte_in_mask (loc, r, mask); |
| } |
| } |
| |
| if (r != NULL_TREE) |
| { |
| for (int i = 0; i < len; i++) |
| if (mask[i]) |
| { |
| if (!ctx->quiet) |
| error_at (loc, "%qs accessing uninitialized byte at offset %d", |
| "__builtin_bit_cast", i); |
| *non_constant_p = true; |
| r = t; |
| break; |
| } |
| if (ptr != buf) |
| XDELETE (ptr); |
| return r; |
| } |
| |
| if (!ctx->quiet) |
| sorry_at (loc, "%qs cannot be constant evaluated because the " |
| "argument cannot be interpreted", "__builtin_bit_cast"); |
| *non_constant_p = true; |
| if (ptr != buf) |
| XDELETE (ptr); |
| return t; |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Evaluate a short-circuited logical expression T in the context |
| of a given constexpr CALL. BAILOUT_VALUE is the value for |
| early return. CONTINUE_VALUE is used here purely for |
| sanity check purposes. */ |
| |
| static tree |
| cxx_eval_logical_expression (const constexpr_ctx *ctx, tree t, |
| tree bailout_value, tree continue_value, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree r; |
| tree lhs = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| vc_prvalue, non_constant_p, |
| overflow_p); |
| VERIFY_CONSTANT (lhs); |
| if (tree_int_cst_equal (lhs, bailout_value)) |
| return lhs; |
| gcc_assert (tree_int_cst_equal (lhs, continue_value)); |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
| vc_prvalue, non_constant_p, |
| overflow_p); |
| VERIFY_CONSTANT (r); |
| return r; |
| } |
| |
| /* REF is a COMPONENT_REF designating a particular field. V is a vector of |
| CONSTRUCTOR elements to initialize (part of) an object containing that |
| field. Return a pointer to the constructor_elt corresponding to the |
| initialization of the field. */ |
| |
| static constructor_elt * |
| base_field_constructor_elt (vec<constructor_elt, va_gc> *v, tree ref) |
| { |
| tree aggr = TREE_OPERAND (ref, 0); |
| tree field = TREE_OPERAND (ref, 1); |
| HOST_WIDE_INT i; |
| constructor_elt *ce; |
| |
| gcc_assert (TREE_CODE (ref) == COMPONENT_REF); |
| |
| if (TREE_CODE (aggr) == COMPONENT_REF) |
| { |
| constructor_elt *base_ce |
| = base_field_constructor_elt (v, aggr); |
| v = CONSTRUCTOR_ELTS (base_ce->value); |
| } |
| |
| for (i = 0; vec_safe_iterate (v, i, &ce); ++i) |
| if (ce->index == field) |
| return ce; |
| |
| gcc_unreachable (); |
| return NULL; |
| } |
| |
| /* Some of the expressions fed to the constexpr mechanism are calls to |
| constructors, which have type void. In that case, return the type being |
| initialized by the constructor. */ |
| |
| static tree |
| initialized_type (tree t) |
| { |
| if (TYPE_P (t)) |
| return t; |
| tree type = TREE_TYPE (t); |
| if (TREE_CODE (t) == CALL_EXPR) |
| { |
| /* A constructor call has void type, so we need to look deeper. */ |
| tree fn = get_function_named_in_call (t); |
| if (fn && TREE_CODE (fn) == FUNCTION_DECL |
| && DECL_CXX_CONSTRUCTOR_P (fn)) |
| type = DECL_CONTEXT (fn); |
| } |
| else if (TREE_CODE (t) == COMPOUND_EXPR) |
| return initialized_type (TREE_OPERAND (t, 1)); |
| else if (TREE_CODE (t) == AGGR_INIT_EXPR) |
| type = TREE_TYPE (AGGR_INIT_EXPR_SLOT (t)); |
| return cv_unqualified (type); |
| } |
| |
| /* We're about to initialize element INDEX of an array or class from VALUE. |
| Set up NEW_CTX appropriately by adjusting .object to refer to the |
| subobject and creating a new CONSTRUCTOR if the element is itself |
| a class or array. */ |
| |
| static void |
| init_subob_ctx (const constexpr_ctx *ctx, constexpr_ctx &new_ctx, |
| tree index, tree &value) |
| { |
| new_ctx = *ctx; |
| |
| if (index && TREE_CODE (index) != INTEGER_CST |
| && TREE_CODE (index) != FIELD_DECL |
| && TREE_CODE (index) != RANGE_EXPR) |
| /* This won't have an element in the new CONSTRUCTOR. */ |
| return; |
| |
| tree type = initialized_type (value); |
| if (!AGGREGATE_TYPE_P (type) && !VECTOR_TYPE_P (type)) |
| /* A non-aggregate member doesn't get its own CONSTRUCTOR. */ |
| return; |
| if (VECTOR_TYPE_P (type) |
| && VECTOR_TYPE_P (TREE_TYPE (ctx->ctor)) |
| && index == NULL_TREE) |
| /* A vector inside of a vector CONSTRUCTOR, e.g. when a larger |
| vector is constructed from smaller vectors, doesn't get its own |
| CONSTRUCTOR either. */ |
| return; |
| |
| /* The sub-aggregate initializer might contain a placeholder; |
| update object to refer to the subobject and ctor to refer to |
| the (newly created) sub-initializer. */ |
| if (ctx->object) |
| { |
| if (index == NULL_TREE || TREE_CODE (index) == RANGE_EXPR) |
| /* There's no well-defined subobject for this index. */ |
| new_ctx.object = NULL_TREE; |
| else |
| new_ctx.object = build_ctor_subob_ref (index, type, ctx->object); |
| } |
| |
| if (is_empty_class (type)) |
| /* Leave ctor null for an empty subobject, they aren't represented in the |
| result of evaluation. */ |
| new_ctx.ctor = NULL_TREE; |
| else |
| { |
| tree elt = build_constructor (type, NULL); |
| CONSTRUCTOR_NO_CLEARING (elt) = true; |
| new_ctx.ctor = elt; |
| } |
| |
| if (TREE_CODE (value) == TARGET_EXPR) |
| /* Avoid creating another CONSTRUCTOR when we expand the TARGET_EXPR. */ |
| value = TARGET_EXPR_INITIAL (value); |
| } |
| |
| /* We're about to process an initializer for a class or array TYPE. Make |
| sure that CTX is set up appropriately. */ |
| |
| static void |
| verify_ctor_sanity (const constexpr_ctx *ctx, tree type) |
| { |
| /* We don't bother building a ctor for an empty base subobject. */ |
| if (is_empty_class (type)) |
| return; |
| |
| /* We're in the middle of an initializer that might involve placeholders; |
| our caller should have created a CONSTRUCTOR for us to put the |
| initializer into. We will either return that constructor or T. */ |
| gcc_assert (ctx->ctor); |
| gcc_assert (same_type_ignoring_top_level_qualifiers_p |
| (type, TREE_TYPE (ctx->ctor))); |
| /* We used to check that ctx->ctor was empty, but that isn't the case when |
| the object is zero-initialized before calling the constructor. */ |
| if (ctx->object) |
| { |
| tree otype = TREE_TYPE (ctx->object); |
| gcc_assert (same_type_ignoring_top_level_qualifiers_p (type, otype) |
| /* Handle flexible array members. */ |
| || (TREE_CODE (otype) == ARRAY_TYPE |
| && TYPE_DOMAIN (otype) == NULL_TREE |
| && TREE_CODE (type) == ARRAY_TYPE |
| && (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (type), TREE_TYPE (otype))))); |
| } |
| gcc_assert (!ctx->object || !DECL_P (ctx->object) |
| || ctx->global->get_value (ctx->object) == ctx->ctor); |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| The expression tree T denotes a C-style array or a C-style |
| aggregate. Reduce it to a constant expression. */ |
| |
| static tree |
| cxx_eval_bare_aggregate (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); |
| bool changed = false; |
| gcc_assert (!BRACE_ENCLOSED_INITIALIZER_P (t)); |
| tree type = TREE_TYPE (t); |
| |
| constexpr_ctx new_ctx; |
| if (TYPE_PTRMEMFUNC_P (type) || VECTOR_TYPE_P (type)) |
| { |
| /* We don't really need the ctx->ctor business for a PMF or |
| vector, but it's simpler to use the same code. */ |
| new_ctx = *ctx; |
| new_ctx.ctor = build_constructor (type, NULL); |
| new_ctx.object = NULL_TREE; |
| ctx = &new_ctx; |
| }; |
| verify_ctor_sanity (ctx, type); |
| vec<constructor_elt, va_gc> **p = nullptr; |
| if (ctx->ctor) |
| { |
| p = &CONSTRUCTOR_ELTS (ctx->ctor); |
| vec_alloc (*p, vec_safe_length (v)); |
| if (CONSTRUCTOR_PLACEHOLDER_BOUNDARY (t)) |
| CONSTRUCTOR_PLACEHOLDER_BOUNDARY (ctx->ctor) = 1; |
| } |
| |
| unsigned i; |
| tree index, value; |
| bool constant_p = true; |
| bool side_effects_p = false; |
| FOR_EACH_CONSTRUCTOR_ELT (v, i, index, value) |
| { |
| tree orig_value = value; |
| /* Like in cxx_eval_store_expression, omit entries for empty fields. */ |
| bool no_slot = TREE_CODE (type) == RECORD_TYPE && is_empty_field (index); |
| init_subob_ctx (ctx, new_ctx, index, value); |
| int pos_hint = -1; |
| if (new_ctx.ctor != ctx->ctor && !no_slot) |
| { |
| /* If we built a new CONSTRUCTOR, attach it now so that other |
| initializers can refer to it. */ |
| constructor_elt *cep = get_or_insert_ctor_field (ctx->ctor, index); |
| cep->value = new_ctx.ctor; |
| pos_hint = cep - (*p)->begin(); |
| } |
| else if (TREE_CODE (type) == UNION_TYPE) |
| /* Otherwise if we're constructing a non-aggregate union member, set |
| the active union member now so that we can later detect and diagnose |
| if its initializer attempts to activate another member. */ |
| get_or_insert_ctor_field (ctx->ctor, index); |
| tree elt = cxx_eval_constant_expression (&new_ctx, value, |
| lval, |
| non_constant_p, overflow_p); |
| /* Don't VERIFY_CONSTANT here. */ |
| if (ctx->quiet && *non_constant_p) |
| break; |
| if (elt != orig_value) |
| changed = true; |
| |
| if (!TREE_CONSTANT (elt)) |
| constant_p = false; |
| if (TREE_SIDE_EFFECTS (elt)) |
| side_effects_p = true; |
| if (index && TREE_CODE (index) == COMPONENT_REF) |
| { |
| /* This is an initialization of a vfield inside a base |
| subaggregate that we already initialized; push this |
| initialization into the previous initialization. */ |
| constructor_elt *inner = base_field_constructor_elt (*p, index); |
| inner->value = elt; |
| changed = true; |
| } |
| else if (no_slot) |
| /* This is an initializer for an empty field; now that we've |
| checked that it's constant, we can ignore it. */ |
| changed = true; |
| else if (index |
| && (TREE_CODE (index) == NOP_EXPR |
| || TREE_CODE (index) == POINTER_PLUS_EXPR)) |
| { |
| /* Old representation of empty bases. FIXME remove. */ |
| gcc_checking_assert (false); |
| gcc_assert (is_empty_class (TREE_TYPE (TREE_TYPE (index)))); |
| changed = true; |
| } |
| else |
| { |
| if (TREE_CODE (type) == UNION_TYPE |
| && (*p)->last().index != index) |
| /* The initializer erroneously changed the active union member that |
| we're initializing. */ |
| gcc_assert (*non_constant_p); |
| else |
| { |
| /* The initializer might have mutated the underlying CONSTRUCTOR, |
| so recompute the location of the target constructer_elt. */ |
| constructor_elt *cep |
| = get_or_insert_ctor_field (ctx->ctor, index, pos_hint); |
| cep->value = elt; |
| } |
| |
| /* Adding or replacing an element might change the ctor's flags. */ |
| TREE_CONSTANT (ctx->ctor) = constant_p; |
| TREE_SIDE_EFFECTS (ctx->ctor) = side_effects_p; |
| } |
| } |
| if (*non_constant_p) |
| return t; |
| if (!changed) |
| { |
| if (VECTOR_TYPE_P (type)) |
| t = fold (t); |
| return t; |
| } |
| t = ctx->ctor; |
| if (!t) |
| t = build_constructor (type, NULL); |
| /* We're done building this CONSTRUCTOR, so now we can interpret an |
| element without an explicit initializer as value-initialized. */ |
| CONSTRUCTOR_NO_CLEARING (t) = false; |
| TREE_CONSTANT (t) = constant_p; |
| TREE_SIDE_EFFECTS (t) = side_effects_p; |
| if (VECTOR_TYPE_P (type)) |
| t = fold (t); |
| return t; |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| The expression tree T is a VEC_INIT_EXPR which denotes the desired |
| initialization of a non-static data member of array type. Reduce it to a |
| CONSTRUCTOR. |
| |
| Note that apart from value-initialization (when VALUE_INIT is true), |
| this is only intended to support value-initialization and the |
| initializations done by defaulted constructors for classes with |
| non-static data members of array type. In this case, VEC_INIT_EXPR_INIT |
| will either be NULL_TREE for the default constructor, or a COMPONENT_REF |
| for the copy/move constructor. */ |
| |
| static tree |
| cxx_eval_vec_init_1 (const constexpr_ctx *ctx, tree atype, tree init, |
| bool value_init, value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree elttype = TREE_TYPE (atype); |
| verify_ctor_sanity (ctx, atype); |
| vec<constructor_elt, va_gc> **p = &CONSTRUCTOR_ELTS (ctx->ctor); |
| bool pre_init = false; |
| unsigned HOST_WIDE_INT i; |
| tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
| |
| if (init && TREE_CODE (init) == CONSTRUCTOR) |
| return cxx_eval_bare_aggregate (ctx, init, lval, |
| non_constant_p, overflow_p); |
| |
| /* For the default constructor, build up a call to the default |
| constructor of the element type. We only need to handle class types |
| here, as for a constructor to be constexpr, all members must be |
| initialized, which for a defaulted default constructor means they must |
| be of a class type with a constexpr default constructor. */ |
| if (TREE_CODE (elttype) == ARRAY_TYPE) |
| /* We only do this at the lowest level. */; |
| else if (value_init) |
| { |
| init = build_value_init (elttype, complain); |
| pre_init = true; |
| } |
| else if (!init) |
| { |
| releasing_vec argvec; |
| init = build_special_member_call (NULL_TREE, complete_ctor_identifier, |
| &argvec, elttype, LOOKUP_NORMAL, |
| complain); |
| init = build_aggr_init_expr (elttype, init); |
| pre_init = true; |
| } |
| |
| bool zeroed_out = false; |
| if (!CONSTRUCTOR_NO_CLEARING (ctx->ctor)) |
| { |
| /* We're initializing an array object that had been zero-initialized |
| earlier. Truncate ctx->ctor, and propagate its zeroed state by |
| clearing CONSTRUCTOR_NO_CLEARING on each of the aggregate element |
| initializers we append to it. */ |
| gcc_checking_assert (initializer_zerop (ctx->ctor)); |
| zeroed_out = true; |
| vec_safe_truncate (*p, 0); |
| } |
| |
| tree nelts = get_array_or_vector_nelts (ctx, atype, non_constant_p, |
| overflow_p); |
| unsigned HOST_WIDE_INT max = tree_to_uhwi (nelts); |
| for (i = 0; i < max; ++i) |
| { |
| tree idx = build_int_cst (size_type_node, i); |
| tree eltinit; |
| bool reuse = false; |
| constexpr_ctx new_ctx; |
| init_subob_ctx (ctx, new_ctx, idx, pre_init ? init : elttype); |
| if (new_ctx.ctor != ctx->ctor) |
| { |
| if (zeroed_out) |
| CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = false; |
| CONSTRUCTOR_APPEND_ELT (*p, idx, new_ctx.ctor); |
| } |
| if (TREE_CODE (elttype) == ARRAY_TYPE) |
| { |
| /* A multidimensional array; recurse. */ |
| if (value_init || init == NULL_TREE) |
| { |
| eltinit = NULL_TREE; |
| reuse = i == 0; |
| } |
| else |
| eltinit = cp_build_array_ref (input_location, init, idx, complain); |
| eltinit = cxx_eval_vec_init_1 (&new_ctx, elttype, eltinit, value_init, |
| lval, |
| non_constant_p, overflow_p); |
| } |
| else if (pre_init) |
| { |
| /* Initializing an element using value or default initialization |
| we just pre-built above. */ |
| if (init == void_node) |
| /* Trivial default-init, don't do anything to the CONSTRUCTOR. */ |
| return ctx->ctor; |
| eltinit = cxx_eval_constant_expression (&new_ctx, init, lval, |
| non_constant_p, overflow_p); |
| reuse = i == 0; |
| } |
| else |
| { |
| /* Copying an element. */ |
| gcc_assert (same_type_ignoring_top_level_qualifiers_p |
| (atype, TREE_TYPE (init))); |
| eltinit = cp_build_array_ref (input_location, init, idx, complain); |
| if (!lvalue_p (init)) |
| eltinit = move (eltinit); |
| eltinit = force_rvalue (eltinit, complain); |
| eltinit = cxx_eval_constant_expression (&new_ctx, eltinit, lval, |
| non_constant_p, overflow_p); |
| } |
| if (*non_constant_p) |
| break; |
| if (new_ctx.ctor != ctx->ctor) |
| { |
| /* We appended this element above; update the value. */ |
| gcc_assert ((*p)->last().index == idx); |
| (*p)->last().value = eltinit; |
| } |
| else |
| CONSTRUCTOR_APPEND_ELT (*p, idx, eltinit); |
| /* Reuse the result of cxx_eval_constant_expression call |
| from the first iteration to all others if it is a constant |
| initializer that doesn't require relocations. */ |
| if (reuse |
| && max > 1 |
| && (eltinit == NULL_TREE |
| || (initializer_constant_valid_p (eltinit, TREE_TYPE (eltinit)) |
| == null_pointer_node))) |
| { |
| if (new_ctx.ctor != ctx->ctor) |
| eltinit = new_ctx.ctor; |
| tree range = build2 (RANGE_EXPR, size_type_node, |
| build_int_cst (size_type_node, 1), |
| build_int_cst (size_type_node, max - 1)); |
| CONSTRUCTOR_APPEND_ELT (*p, range, unshare_constructor (eltinit)); |
| break; |
| } |
| else if (i == 0) |
| vec_safe_reserve (*p, max); |
| } |
| |
| if (!*non_constant_p) |
| { |
| init = ctx->ctor; |
| CONSTRUCTOR_NO_CLEARING (init) = false; |
| } |
| return init; |
| } |
| |
| static tree |
| cxx_eval_vec_init (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree atype = TREE_TYPE (t); |
| tree init = VEC_INIT_EXPR_INIT (t); |
| bool value_init = VEC_INIT_EXPR_VALUE_INIT (t); |
| if (!init || !BRACE_ENCLOSED_INITIALIZER_P (init)) |
| ; |
| else if (CONSTRUCTOR_NELTS (init) == 0 |
| && !CP_AGGREGATE_TYPE_P (strip_array_types (atype))) |
| { |
| /* Handle {} as value-init. */ |
| init = NULL_TREE; |
| value_init = true; |
| } |
| else |
| { |
| /* This is a more complicated case, like needing to loop over trailing |
| elements; call build_vec_init and evaluate the result. */ |
| tsubst_flags_t complain = ctx->quiet ? tf_none : tf_warning_or_error; |
| constexpr_ctx new_ctx = *ctx; |
| if (!ctx->object) |
| { |
| /* We want to have an initialization target for an VEC_INIT_EXPR. |
| If we don't already have one in CTX, use the VEC_INIT_EXPR_SLOT. */ |
| new_ctx.object = VEC_INIT_EXPR_SLOT (t); |
| tree ctor = new_ctx.ctor = build_constructor (atype, NULL); |
| CONSTRUCTOR_NO_CLEARING (ctor) = true; |
| ctx->global->put_value (new_ctx.object, ctor); |
| ctx = &new_ctx; |
| } |
| init = expand_vec_init_expr (ctx->object, t, complain); |
| return cxx_eval_constant_expression (ctx, init, lval, non_constant_p, |
| overflow_p); |
| } |
| tree r = cxx_eval_vec_init_1 (ctx, atype, init, value_init, |
| lval, non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| else |
| return r; |
| } |
| |
| /* Like same_type_ignoring_top_level_qualifiers_p, but also handle the case |
| where the desired type is an array of unknown bounds because the variable |
| has had its bounds deduced since the wrapping expression was created. */ |
| |
| static bool |
| same_type_ignoring_tlq_and_bounds_p (tree type1, tree type2) |
| { |
| while (TREE_CODE (type1) == ARRAY_TYPE |
| && TREE_CODE (type2) == ARRAY_TYPE |
| && (!TYPE_DOMAIN (type1) || !TYPE_DOMAIN (type2))) |
| { |
| type1 = TREE_TYPE (type1); |
| type2 = TREE_TYPE (type2); |
| } |
| return same_type_ignoring_top_level_qualifiers_p (type1, type2); |
| } |
| |
| /* Try to determine the currently active union member for an expression |
| with UNION_TYPE. If it can be determined, return the FIELD_DECL, |
| otherwise return NULL_TREE. */ |
| |
| static tree |
| cxx_union_active_member (const constexpr_ctx *ctx, tree t) |
| { |
| constexpr_ctx new_ctx = *ctx; |
| new_ctx.quiet = true; |
| bool non_constant_p = false, overflow_p = false; |
| tree ctor = cxx_eval_constant_expression (&new_ctx, t, vc_prvalue, |
| &non_constant_p, |
| &overflow_p); |
| if (TREE_CODE (ctor) == CONSTRUCTOR |
| && CONSTRUCTOR_NELTS (ctor) == 1 |
| && CONSTRUCTOR_ELT (ctor, 0)->index |
| && TREE_CODE (CONSTRUCTOR_ELT (ctor, 0)->index) == FIELD_DECL) |
| return CONSTRUCTOR_ELT (ctor, 0)->index; |
| return NULL_TREE; |
| } |
| |
| /* Helper function for cxx_fold_indirect_ref_1, called recursively. */ |
| |
| static tree |
| cxx_fold_indirect_ref_1 (const constexpr_ctx *ctx, location_t loc, tree type, |
| tree op, unsigned HOST_WIDE_INT off, bool *empty_base) |
| { |
| tree optype = TREE_TYPE (op); |
| unsigned HOST_WIDE_INT const_nunits; |
| if (off == 0 && similar_type_p (optype, type)) |
| return op; |
| else if (TREE_CODE (optype) == COMPLEX_TYPE |
| && similar_type_p (type, TREE_TYPE (optype))) |
| { |
| /* *(foo *)&complexfoo => __real__ complexfoo */ |
| if (off == 0) |
| return build1_loc (loc, REALPART_EXPR, type, op); |
| /* ((foo*)&complexfoo)[1] => __imag__ complexfoo */ |
| else if (tree_to_uhwi (TYPE_SIZE_UNIT (type)) == off) |
| return build1_loc (loc, IMAGPART_EXPR, type, op); |
| } |
| /* ((foo*)&vectorfoo)[x] => BIT_FIELD_REF<vectorfoo,...> */ |
| else if (VECTOR_TYPE_P (optype) |
| && similar_type_p (type, TREE_TYPE (optype)) |
| && TYPE_VECTOR_SUBPARTS (optype).is_constant (&const_nunits)) |
| { |
| unsigned HOST_WIDE_INT part_width = tree_to_uhwi (TYPE_SIZE_UNIT (type)); |
| unsigned HOST_WIDE_INT max_offset = part_width * const_nunits; |
| if (off < max_offset && off % part_width == 0) |
| { |
| tree index = bitsize_int (off * BITS_PER_UNIT); |
| return build3_loc (loc, BIT_FIELD_REF, type, op, |
| TYPE_SIZE (type), index); |
| } |
| } |
| /* ((foo *)&fooarray)[x] => fooarray[x] */ |
| else if (TREE_CODE (optype) == ARRAY_TYPE |
| && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (optype))) |
| && !integer_zerop (TYPE_SIZE_UNIT (TREE_TYPE (optype)))) |
| { |
| tree type_domain = TYPE_DOMAIN (optype); |
| tree min_val = size_zero_node; |
| if (type_domain && TYPE_MIN_VALUE (type_domain)) |
| min_val = TYPE_MIN_VALUE (type_domain); |
| unsigned HOST_WIDE_INT el_sz |
| = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (optype))); |
| unsigned HOST_WIDE_INT idx = off / el_sz; |
| unsigned HOST_WIDE_INT rem = off % el_sz; |
| if (tree_fits_uhwi_p (min_val)) |
| { |
| tree index = size_int (idx + tree_to_uhwi (min_val)); |
| op = build4_loc (loc, ARRAY_REF, TREE_TYPE (optype), op, index, |
| NULL_TREE, NULL_TREE); |
| return cxx_fold_indirect_ref_1 (ctx, loc, type, op, rem, |
| empty_base); |
| } |
| } |
| /* ((foo *)&struct_with_foo_field)[x] => COMPONENT_REF */ |
| else if (TREE_CODE (optype) == RECORD_TYPE |
| || TREE_CODE (optype) == UNION_TYPE) |
| { |
| if (TREE_CODE (optype) == UNION_TYPE) |
| /* For unions prefer the currently active member. */ |
| if (tree field = cxx_union_active_member (ctx, op)) |
| { |
| unsigned HOST_WIDE_INT el_sz |
| = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (field))); |
| if (off < el_sz) |
| { |
| tree cop = build3 (COMPONENT_REF, TREE_TYPE (field), |
| op, field, NULL_TREE); |
| if (tree ret = cxx_fold_indirect_ref_1 (ctx, loc, type, cop, |
| off, empty_base)) |
| return ret; |
| } |
| } |
| for (tree field = TYPE_FIELDS (optype); |
| field; field = DECL_CHAIN (field)) |
| if (TREE_CODE (field) == FIELD_DECL |
| && TREE_TYPE (field) != error_mark_node |
| && tree_fits_uhwi_p (TYPE_SIZE_UNIT (TREE_TYPE (field)))) |
| { |
| tree pos = byte_position (field); |
| if (!tree_fits_uhwi_p (pos)) |
| continue; |
| unsigned HOST_WIDE_INT upos = tree_to_uhwi (pos); |
| unsigned HOST_WIDE_INT el_sz |
| = tree_to_uhwi (TYPE_SIZE_UNIT (TREE_TYPE (field))); |
| if (upos <= off && off < upos + el_sz) |
| { |
| tree cop = build3 (COMPONENT_REF, TREE_TYPE (field), |
| op, field, NULL_TREE); |
| if (tree ret = cxx_fold_indirect_ref_1 (ctx, loc, type, cop, |
| off - upos, |
| empty_base)) |
| return ret; |
| } |
| } |
| /* Also handle conversion to an empty base class, which |
| is represented with a NOP_EXPR. */ |
| if (is_empty_class (type) |
| && CLASS_TYPE_P (optype) |
| && DERIVED_FROM_P (type, optype)) |
| { |
| if (empty_base) |
| *empty_base = true; |
| return op; |
| } |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* A less strict version of fold_indirect_ref_1, which requires cv-quals to |
| match. We want to be less strict for simple *& folding; if we have a |
| non-const temporary that we access through a const pointer, that should |
| work. We handle this here rather than change fold_indirect_ref_1 |
| because we're dealing with things like ADDR_EXPR of INTEGER_CST which |
| don't really make sense outside of constant expression evaluation. Also |
| we want to allow folding to COMPONENT_REF, which could cause trouble |
| with TBAA in fold_indirect_ref_1. */ |
| |
| static tree |
| cxx_fold_indirect_ref (const constexpr_ctx *ctx, location_t loc, tree type, |
| tree op0, bool *empty_base /* = NULL*/) |
| { |
| tree sub = op0; |
| tree subtype; |
| poly_uint64 const_op01; |
| |
| /* STRIP_NOPS, but stop if REINTERPRET_CAST_P. */ |
| while (CONVERT_EXPR_P (sub) || TREE_CODE (sub) == NON_LVALUE_EXPR |
| || TREE_CODE (sub) == VIEW_CONVERT_EXPR) |
| { |
| if (TREE_CODE (sub) == NOP_EXPR |
| && REINTERPRET_CAST_P (sub)) |
| return NULL_TREE; |
| sub = TREE_OPERAND (sub, 0); |
| } |
| |
| subtype = TREE_TYPE (sub); |
| if (!INDIRECT_TYPE_P (subtype)) |
| return NULL_TREE; |
| |
| /* Canonicalizes the given OBJ/OFF pair by iteratively absorbing |
| the innermost component into the offset until it would make the |
| offset positive, so that cxx_fold_indirect_ref_1 can identify |
| more folding opportunities. */ |
| auto canonicalize_obj_off = [] (tree& obj, tree& off) { |
| while (TREE_CODE (obj) == COMPONENT_REF |
| && (tree_int_cst_sign_bit (off) || integer_zerop (off))) |
| { |
| tree field = TREE_OPERAND (obj, 1); |
| tree pos = byte_position (field); |
| if (integer_zerop (off) && integer_nonzerop (pos)) |
| /* If the offset is already 0, keep going as long as the |
| component is at position 0. */ |
| break; |
| off = int_const_binop (PLUS_EXPR, off, pos); |
| obj = TREE_OPERAND (obj, 0); |
| } |
| }; |
| |
| if (TREE_CODE (sub) == ADDR_EXPR) |
| { |
| tree op = TREE_OPERAND (sub, 0); |
| tree optype = TREE_TYPE (op); |
| |
| /* *&CONST_DECL -> to the value of the const decl. */ |
| if (TREE_CODE (op) == CONST_DECL) |
| return DECL_INITIAL (op); |
| /* *&p => p; make sure to handle *&"str"[cst] here. */ |
| if (similar_type_p (optype, type)) |
| { |
| tree fop = fold_read_from_constant_string (op); |
| if (fop) |
| return fop; |
| else |
| return op; |
| } |
| else |
| { |
| tree off = integer_zero_node; |
| canonicalize_obj_off (op, off); |
| gcc_assert (integer_zerop (off)); |
| return cxx_fold_indirect_ref_1 (ctx, loc, type, op, 0, empty_base); |
| } |
| } |
| else if (TREE_CODE (sub) == POINTER_PLUS_EXPR |
| && tree_fits_uhwi_p (TREE_OPERAND (sub, 1))) |
| { |
| tree op00 = TREE_OPERAND (sub, 0); |
| tree off = TREE_OPERAND (sub, 1); |
| |
| STRIP_NOPS (op00); |
| if (TREE_CODE (op00) == ADDR_EXPR) |
| { |
| tree obj = TREE_OPERAND (op00, 0); |
| canonicalize_obj_off (obj, off); |
| return cxx_fold_indirect_ref_1 (ctx, loc, type, obj, |
| tree_to_uhwi (off), empty_base); |
| } |
| } |
| /* *(foo *)fooarrptr => (*fooarrptr)[0] */ |
| else if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE |
| && similar_type_p (type, TREE_TYPE (TREE_TYPE (subtype)))) |
| { |
| tree type_domain; |
| tree min_val = size_zero_node; |
| tree newsub |
| = cxx_fold_indirect_ref (ctx, loc, TREE_TYPE (subtype), sub, NULL); |
| if (newsub) |
| sub = newsub; |
| else |
| sub = build1_loc (loc, INDIRECT_REF, TREE_TYPE (subtype), sub); |
| type_domain = TYPE_DOMAIN (TREE_TYPE (sub)); |
| if (type_domain && TYPE_MIN_VALUE (type_domain)) |
| min_val = TYPE_MIN_VALUE (type_domain); |
| return build4_loc (loc, ARRAY_REF, type, sub, min_val, NULL_TREE, |
| NULL_TREE); |
| } |
| |
| return NULL_TREE; |
| } |
| |
| static tree |
| cxx_eval_indirect_ref (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| tree orig_op0 = TREE_OPERAND (t, 0); |
| bool empty_base = false; |
| |
| /* We can handle a MEM_REF like an INDIRECT_REF, if MEM_REF's second |
| operand is an integer-zero. Otherwise reject the MEM_REF for now. */ |
| |
| if (TREE_CODE (t) == MEM_REF |
| && (!TREE_OPERAND (t, 1) || !integer_zerop (TREE_OPERAND (t, 1)))) |
| { |
| gcc_assert (ctx->quiet); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* First try to simplify it directly. */ |
| tree r = cxx_fold_indirect_ref (ctx, EXPR_LOCATION (t), TREE_TYPE (t), |
| orig_op0, &empty_base); |
| if (!r) |
| { |
| /* If that didn't work, evaluate the operand first. */ |
| tree op0 = cxx_eval_constant_expression (ctx, orig_op0, |
| vc_prvalue, non_constant_p, |
| overflow_p); |
| /* Don't VERIFY_CONSTANT here. */ |
| if (*non_constant_p) |
| return t; |
| |
| if (!lval && integer_zerop (op0)) |
| { |
| if (!ctx->quiet) |
| error ("dereferencing a null pointer"); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| r = cxx_fold_indirect_ref (ctx, EXPR_LOCATION (t), TREE_TYPE (t), op0, |
| &empty_base); |
| if (r == NULL_TREE) |
| { |
| /* We couldn't fold to a constant value. Make sure it's not |
| something we should have been able to fold. */ |
| tree sub = op0; |
| STRIP_NOPS (sub); |
| if (TREE_CODE (sub) == ADDR_EXPR) |
| { |
| gcc_assert (!similar_type_p |
| (TREE_TYPE (TREE_TYPE (sub)), TREE_TYPE (t))); |
| /* DR 1188 says we don't have to deal with this. */ |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "accessing value of %qE through a %qT glvalue in a " |
| "constant expression", build_fold_indirect_ref (sub), |
| TREE_TYPE (t)); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| if (lval == vc_glvalue && op0 != orig_op0) |
| return build1 (INDIRECT_REF, TREE_TYPE (t), op0); |
| if (!lval) |
| VERIFY_CONSTANT (t); |
| return t; |
| } |
| } |
| |
| r = cxx_eval_constant_expression (ctx, r, |
| lval, non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| |
| /* If we're pulling out the value of an empty base, just return an empty |
| CONSTRUCTOR. */ |
| if (empty_base && !lval) |
| { |
| r = build_constructor (TREE_TYPE (t), NULL); |
| TREE_CONSTANT (r) = true; |
| } |
| |
| return r; |
| } |
| |
| /* Complain about R, a VAR_DECL, not being usable in a constant expression. |
| FUNDEF_P is true if we're checking a constexpr function body. |
| Shared between potential_constant_expression and |
| cxx_eval_constant_expression. */ |
| |
| static void |
| non_const_var_error (location_t loc, tree r, bool fundef_p) |
| { |
| auto_diagnostic_group d; |
| tree type = TREE_TYPE (r); |
| if (DECL_NAME (r) == heap_uninit_identifier |
| || DECL_NAME (r) == heap_identifier |
| || DECL_NAME (r) == heap_vec_uninit_identifier |
| || DECL_NAME (r) == heap_vec_identifier) |
| { |
| if (constexpr_error (loc, fundef_p, "the content of uninitialized " |
| "storage is not usable in a constant expression")) |
| inform (DECL_SOURCE_LOCATION (r), "allocated here"); |
| return; |
| } |
| if (DECL_NAME (r) == heap_deleted_identifier) |
| { |
| if (constexpr_error (loc, fundef_p, "use of allocated storage after " |
| "deallocation in a constant expression")) |
| inform (DECL_SOURCE_LOCATION (r), "allocated here"); |
| return; |
| } |
| if (!constexpr_error (loc, fundef_p, "the value of %qD is not usable in " |
| "a constant expression", r)) |
| return; |
| /* Avoid error cascade. */ |
| if (DECL_INITIAL (r) == error_mark_node) |
| return; |
| if (DECL_DECLARED_CONSTEXPR_P (r)) |
| inform (DECL_SOURCE_LOCATION (r), |
| "%qD used in its own initializer", r); |
| else if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) |
| { |
| if (!CP_TYPE_CONST_P (type)) |
| inform (DECL_SOURCE_LOCATION (r), |
| "%q#D is not const", r); |
| else if (CP_TYPE_VOLATILE_P (type)) |
| inform (DECL_SOURCE_LOCATION (r), |
| "%q#D is volatile", r); |
| else if (!DECL_INITIAL (r) |
| || !TREE_CONSTANT (DECL_INITIAL (r)) |
| || !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r)) |
| inform (DECL_SOURCE_LOCATION (r), |
| "%qD was not initialized with a constant " |
| "expression", r); |
| else |
| gcc_unreachable (); |
| } |
| else if (TYPE_REF_P (type)) |
| inform (DECL_SOURCE_LOCATION (r), |
| "%qD was not initialized with a constant " |
| "expression", r); |
| else |
| { |
| if (cxx_dialect >= cxx11 && !DECL_DECLARED_CONSTEXPR_P (r)) |
| inform (DECL_SOURCE_LOCATION (r), |
| "%qD was not declared %<constexpr%>", r); |
| else |
| inform (DECL_SOURCE_LOCATION (r), |
| "%qD does not have integral or enumeration type", |
| r); |
| } |
| } |
| |
| /* Subroutine of cxx_eval_constant_expression. |
| Like cxx_eval_unary_expression, except for trinary expressions. */ |
| |
| static tree |
| cxx_eval_trinary_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| int i; |
| tree args[3]; |
| tree val; |
| |
| for (i = 0; i < 3; i++) |
| { |
| args[i] = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, i), |
| lval, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (args[i]); |
| } |
| |
| val = fold_ternary_loc (EXPR_LOCATION (t), TREE_CODE (t), TREE_TYPE (t), |
| args[0], args[1], args[2]); |
| if (val == NULL_TREE) |
| return t; |
| VERIFY_CONSTANT (val); |
| return val; |
| } |
| |
| /* True if T was declared in a function declared to be constexpr, and |
| therefore potentially constant in C++14. */ |
| |
| bool |
| var_in_constexpr_fn (tree t) |
| { |
| tree ctx = DECL_CONTEXT (t); |
| return (ctx && TREE_CODE (ctx) == FUNCTION_DECL |
| && DECL_DECLARED_CONSTEXPR_P (ctx)); |
| } |
| |
| /* True if a function might be constexpr: either a function that was |
| declared constexpr, or a C++17 lambda op(). */ |
| |
| bool |
| maybe_constexpr_fn (tree t) |
| { |
| return (DECL_DECLARED_CONSTEXPR_P (t) |
| || (cxx_dialect >= cxx17 && LAMBDA_FUNCTION_P (t)) |
| || (flag_implicit_constexpr |
| && DECL_DECLARED_INLINE_P (STRIP_TEMPLATE (t)))); |
| } |
| |
| /* True if T was declared in a function that might be constexpr: either a |
| function that was declared constexpr, or a C++17 lambda op(). */ |
| |
| bool |
| var_in_maybe_constexpr_fn (tree t) |
| { |
| return (DECL_FUNCTION_SCOPE_P (t) |
| && maybe_constexpr_fn (DECL_CONTEXT (t))); |
| } |
| |
| /* We're assigning INIT to TARGET. In do_build_copy_constructor and |
| build_over_call we implement trivial copy of a class with tail padding using |
| assignment of character arrays, which is valid in normal code, but not in |
| constexpr evaluation. We don't need to worry about clobbering tail padding |
| in constexpr evaluation, so strip the type punning. */ |
| |
| static void |
| maybe_simplify_trivial_copy (tree &target, tree &init) |
| { |
| if (TREE_CODE (target) == MEM_REF |
| && TREE_CODE (init) == MEM_REF |
| && TREE_TYPE (target) == TREE_TYPE (init) |
| && TREE_CODE (TREE_TYPE (target)) == ARRAY_TYPE |
| && TREE_TYPE (TREE_TYPE (target)) == unsigned_char_type_node) |
| { |
| target = build_fold_indirect_ref (TREE_OPERAND (target, 0)); |
| init = build_fold_indirect_ref (TREE_OPERAND (init, 0)); |
| } |
| } |
| |
| /* Returns true if REF, which is a COMPONENT_REF, has any fields |
| of constant type. This does not check for 'mutable', so the |
| caller is expected to be mindful of that. */ |
| |
| static bool |
| cref_has_const_field (tree ref) |
| { |
| while (TREE_CODE (ref) == COMPONENT_REF) |
| { |
| if (CP_TYPE_CONST_P (TREE_TYPE (TREE_OPERAND (ref, 1)))) |
| return true; |
| ref = TREE_OPERAND (ref, 0); |
| } |
| return false; |
| } |
| |
| /* Return true if we are modifying something that is const during constant |
| expression evaluation. CODE is the code of the statement, OBJ is the |
| object in question, MUTABLE_P is true if one of the subobjects were |
| declared mutable. */ |
| |
| static bool |
| modifying_const_object_p (tree_code code, tree obj, bool mutable_p) |
| { |
| /* If this is initialization, there's no problem. */ |
| if (code != MODIFY_EXPR) |
| return false; |
| |
| /* [basic.type.qualifier] "A const object is an object of type |
| const T or a non-mutable subobject of a const object." */ |
| if (mutable_p) |
| return false; |
| |
| if (TREE_READONLY (obj)) |
| return true; |
| |
| if (CP_TYPE_CONST_P (TREE_TYPE (obj))) |
| { |
| /* Although a COMPONENT_REF may have a const type, we should |
| only consider it modifying a const object when any of the |
| field components is const. This can happen when using |
| constructs such as const_cast<const T &>(m), making something |
| const even though it wasn't declared const. */ |
| if (TREE_CODE (obj) == COMPONENT_REF) |
| return cref_has_const_field (obj); |
| else |
| return true; |
| } |
| |
| return false; |
| } |
| |
| /* Evaluate an INIT_EXPR or MODIFY_EXPR. */ |
| |
| static tree |
| cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| constexpr_ctx new_ctx = *ctx; |
| |
| tree init = TREE_OPERAND (t, 1); |
| if (TREE_CLOBBER_P (init)) |
| /* Just ignore clobbers. */ |
| return void_node; |
| |
| /* First we figure out where we're storing to. */ |
| tree target = TREE_OPERAND (t, 0); |
| |
| maybe_simplify_trivial_copy (target, init); |
| |
| tree type = TREE_TYPE (target); |
| bool preeval = SCALAR_TYPE_P (type) || TREE_CODE (t) == MODIFY_EXPR; |
| if (preeval) |
| { |
| /* Evaluate the value to be stored without knowing what object it will be |
| stored in, so that any side-effects happen first. */ |
| if (!SCALAR_TYPE_P (type)) |
| new_ctx.ctor = new_ctx.object = NULL_TREE; |
| init = cxx_eval_constant_expression (&new_ctx, init, vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| } |
| |
| bool evaluated = false; |
| if (lval == vc_glvalue) |
| { |
| /* If we want to return a reference to the target, we need to evaluate it |
| as a whole; otherwise, only evaluate the innermost piece to avoid |
| building up unnecessary *_REFs. */ |
| target = cxx_eval_constant_expression (ctx, target, lval, |
| non_constant_p, overflow_p); |
| evaluated = true; |
| if (*non_constant_p) |
| return t; |
| } |
| |
| /* Find the underlying variable. */ |
| releasing_vec refs; |
| tree object = NULL_TREE; |
| /* If we're modifying a const object, save it. */ |
| tree const_object_being_modified = NULL_TREE; |
| bool mutable_p = false; |
| for (tree probe = target; object == NULL_TREE; ) |
| { |
| switch (TREE_CODE (probe)) |
| { |
| case BIT_FIELD_REF: |
| case COMPONENT_REF: |
| case ARRAY_REF: |
| { |
| tree ob = TREE_OPERAND (probe, 0); |
| tree elt = TREE_OPERAND (probe, 1); |
| if (TREE_CODE (elt) == FIELD_DECL && DECL_MUTABLE_P (elt)) |
| mutable_p = true; |
| if (TREE_CODE (probe) == ARRAY_REF) |
| { |
| elt = eval_and_check_array_index (ctx, probe, false, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| } |
| /* We don't check modifying_const_object_p for ARRAY_REFs. Given |
| "int a[10]", an ARRAY_REF "a[2]" can be "const int", even though |
| the array isn't const. Instead, check "a" in the next iteration; |
| that will detect modifying "const int a[10]". */ |
| else if (evaluated |
| && modifying_const_object_p (TREE_CODE (t), probe, |
| mutable_p) |
| && const_object_being_modified == NULL_TREE) |
| const_object_being_modified = probe; |
| vec_safe_push (refs, elt); |
| vec_safe_push (refs, TREE_TYPE (probe)); |
| probe = ob; |
| } |
| break; |
| |
| case REALPART_EXPR: |
| gcc_assert (probe == target); |
| vec_safe_push (refs, probe); |
| vec_safe_push (refs, TREE_TYPE (probe)); |
| probe = TREE_OPERAND (probe, 0); |
| break; |
| |
| case IMAGPART_EXPR: |
| gcc_assert (probe == target); |
| vec_safe_push (refs, probe); |
| vec_safe_push (refs, TREE_TYPE (probe)); |
| probe = TREE_OPERAND (probe, 0); |
| break; |
| |
| default: |
| if (evaluated) |
| object = probe; |
| else |
| { |
| probe = cxx_eval_constant_expression (ctx, probe, vc_glvalue, |
| non_constant_p, overflow_p); |
| evaluated = true; |
| if (*non_constant_p) |
| return t; |
| } |
| break; |
| } |
| } |
| |
| if (modifying_const_object_p (TREE_CODE (t), object, mutable_p) |
| && const_object_being_modified == NULL_TREE) |
| const_object_being_modified = object; |
| |
| /* And then find/build up our initializer for the path to the subobject |
| we're initializing. */ |
| tree *valp; |
| if (DECL_P (object)) |
| valp = ctx->global->get_value_ptr (object); |
| else |
| valp = NULL; |
| if (!valp) |
| { |
| /* A constant-expression cannot modify objects from outside the |
| constant-expression. */ |
| if (!ctx->quiet) |
| error ("modification of %qE is not a constant expression", object); |
| *non_constant_p = true; |
| return t; |
| } |
| type = TREE_TYPE (object); |
| bool no_zero_init = true; |
| |
| auto_vec<tree *> ctors; |
| releasing_vec indexes; |
| auto_vec<int> index_pos_hints; |
| bool activated_union_member_p = false; |
| bool empty_base = false; |
| while (!refs->is_empty ()) |
| { |
| if (*valp == NULL_TREE) |
| { |
| *valp = build_constructor (type, NULL); |
| CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
| } |
| else if (TREE_CODE (*valp) == STRING_CST) |
| { |
| /* An array was initialized with a string constant, and now |
| we're writing into one of its elements. Explode the |
| single initialization into a set of element |
| initializations. */ |
| gcc_assert (TREE_CODE (type) == ARRAY_TYPE); |
| |
| tree string = *valp; |
| tree elt_type = TREE_TYPE (type); |
| unsigned chars_per_elt = (TYPE_PRECISION (elt_type) |
| / TYPE_PRECISION (char_type_node)); |
| unsigned num_elts = TREE_STRING_LENGTH (string) / chars_per_elt; |
| tree ary_ctor = build_constructor (type, NULL); |
| |
| vec_safe_reserve (CONSTRUCTOR_ELTS (ary_ctor), num_elts); |
| for (unsigned ix = 0; ix != num_elts; ix++) |
| { |
| constructor_elt elt = |
| { |
| build_int_cst (size_type_node, ix), |
| extract_string_elt (string, chars_per_elt, ix) |
| }; |
| CONSTRUCTOR_ELTS (ary_ctor)->quick_push (elt); |
| } |
| |
| *valp = ary_ctor; |
| } |
| |
| enum tree_code code = TREE_CODE (type); |
| tree reftype = refs->pop(); |
| tree index = refs->pop(); |
| |
| if (code == COMPLEX_TYPE) |
| { |
| if (TREE_CODE (*valp) == COMPLEX_CST) |
| *valp = build2 (COMPLEX_EXPR, type, TREE_REALPART (*valp), |
| TREE_IMAGPART (*valp)); |
| else if (TREE_CODE (*valp) == CONSTRUCTOR |
| && CONSTRUCTOR_NELTS (*valp) == 0 |
| && CONSTRUCTOR_NO_CLEARING (*valp)) |
| { |
| tree r = build_constructor (reftype, NULL); |
| CONSTRUCTOR_NO_CLEARING (r) = 1; |
| *valp = build2 (COMPLEX_EXPR, type, r, r); |
| } |
| gcc_assert (TREE_CODE (*valp) == COMPLEX_EXPR); |
| ctors.safe_push (valp); |
| vec_safe_push (indexes, index); |
| valp = &TREE_OPERAND (*valp, TREE_CODE (index) == IMAGPART_EXPR); |
| gcc_checking_assert (refs->is_empty ()); |
| type = reftype; |
| break; |
| } |
| |
| /* If the value of object is already zero-initialized, any new ctors for |
| subobjects will also be zero-initialized. */ |
| no_zero_init = CONSTRUCTOR_NO_CLEARING (*valp); |
| |
| if (code == RECORD_TYPE && is_empty_field (index)) |
| /* Don't build a sub-CONSTRUCTOR for an empty base or field, as they |
| have no data and might have an offset lower than previously declared |
| fields, which confuses the middle-end. The code below will notice |
| that we don't have a CONSTRUCTOR for our inner target and just |
| return init. */ |
| { |
| empty_base = true; |
| break; |
| } |
| |
| type = reftype; |
| |
| if (code == UNION_TYPE && CONSTRUCTOR_NELTS (*valp) |
| && CONSTRUCTOR_ELT (*valp, 0)->index != index) |
| { |
| if (cxx_dialect < cxx20) |
| { |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "change of the active member of a union " |
| "from %qD to %qD", |
| CONSTRUCTOR_ELT (*valp, 0)->index, |
| index); |
| *non_constant_p = true; |
| } |
| else if (TREE_CODE (t) == MODIFY_EXPR |
| && CONSTRUCTOR_NO_CLEARING (*valp)) |
| { |
| /* Diagnose changing the active union member while the union |
| is in the process of being initialized. */ |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "change of the active member of a union " |
| "from %qD to %qD during initialization", |
| CONSTRUCTOR_ELT (*valp, 0)->index, |
| index); |
| *non_constant_p = true; |
| } |
| no_zero_init = true; |
| } |
| |
| ctors.safe_push (valp); |
| vec_safe_push (indexes, index); |
| |
| constructor_elt *cep |
| = get_or_insert_ctor_field (*valp, index); |
| index_pos_hints.safe_push (cep - CONSTRUCTOR_ELTS (*valp)->begin()); |
| |
| if (code == UNION_TYPE) |
| activated_union_member_p = true; |
| |
| valp = &cep->value; |
| } |
| |
| /* For initialization of an empty base, the original target will be |
| *(base*)this, evaluation of which resolves to the object |
| argument, which has the derived type rather than the base type. */ |
| if (!empty_base && !(same_type_ignoring_top_level_qualifiers_p |
| (initialized_type (init), type))) |
| { |
| gcc_assert (is_empty_class (TREE_TYPE (target))); |
| empty_base = true; |
| } |
| |
| /* Detect modifying a constant object in constexpr evaluation. |
| We have found a const object that is being modified. Figure out |
| if we need to issue an error. Consider |
| |
| struct A { |
| int n; |
| constexpr A() : n(1) { n = 2; } // #1 |
| }; |
| struct B { |
| const A a; |
| constexpr B() { a.n = 3; } // #2 |
| }; |
| constexpr B b{}; |
| |
| #1 is OK, since we're modifying an object under construction, but |
| #2 is wrong, since "a" is const and has been fully constructed. |
| To track it, we use the TREE_READONLY bit in the object's CONSTRUCTOR |
| which means that the object is read-only. For the example above, the |
| *ctors stack at the point of #2 will look like: |
| |
| ctors[0] = {.a={.n=2}} TREE_READONLY = 0 |
| ctors[1] = {.n=2} TREE_READONLY = 1 |
| |
| and we're modifying "b.a", so we search the stack and see if the |
| constructor for "b.a" has already run. */ |
| if (const_object_being_modified) |
| { |
| bool fail = false; |
| tree const_objtype |
| = strip_array_types (TREE_TYPE (const_object_being_modified)); |
| if (!CLASS_TYPE_P (const_objtype)) |
| fail = true; |
| else |
| { |
| /* [class.ctor]p5 "A constructor can be invoked for a const, |
| volatile, or const volatile object. const and volatile |
| semantics are not applied on an object under construction. |
| They come into effect when the constructor for the most |
| derived object ends." */ |
| for (tree *elt : ctors) |
| if (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (const_object_being_modified), TREE_TYPE (*elt))) |
| { |
| fail = TREE_READONLY (*elt); |
| break; |
| } |
| } |
| if (fail) |
| { |
| if (!ctx->quiet) |
| modifying_const_object_error (t, const_object_being_modified); |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| |
| if (!preeval) |
| { |
| /* We're handling an INIT_EXPR of class type, so the value of the |
| initializer can depend on the object it's initializing. */ |
| |
| /* Create a new CONSTRUCTOR in case evaluation of the initializer |
| wants to modify it. */ |
| if (*valp == NULL_TREE) |
| { |
| *valp = build_constructor (type, NULL); |
| CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
| } |
| new_ctx.ctor = empty_base ? NULL_TREE : *valp; |
| new_ctx.object = target; |
| /* Avoid temporary materialization when initializing from a TARGET_EXPR. |
| We don't need to mess with AGGR_EXPR_SLOT/VEC_INIT_EXPR_SLOT because |
| expansion of those trees uses ctx instead. */ |
| if (TREE_CODE (init) == TARGET_EXPR) |
| if (tree tinit = TARGET_EXPR_INITIAL (init)) |
| init = tinit; |
| init = cxx_eval_constant_expression (&new_ctx, init, vc_prvalue, |
| non_constant_p, overflow_p); |
| /* The hash table might have moved since the get earlier, and the |
| initializer might have mutated the underlying CONSTRUCTORs, so we must |
| recompute VALP. */ |
| valp = ctx->global->get_value_ptr (object); |
| for (unsigned i = 0; i < vec_safe_length (indexes); i++) |
| { |
| ctors[i] = valp; |
| constructor_elt *cep |
| = get_or_insert_ctor_field (*valp, indexes[i], index_pos_hints[i]); |
| valp = &cep->value; |
| } |
| } |
| |
| if (*non_constant_p) |
| return t; |
| |
| /* Don't share a CONSTRUCTOR that might be changed later. */ |
| init = unshare_constructor (init); |
| |
| gcc_checking_assert (!*valp || (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (*valp), type))); |
| if (empty_base) |
| { |
| /* Just evaluate the initializer and return, since there's no actual data |
| to store, and we didn't build a CONSTRUCTOR. */ |
| if (!*valp) |
| { |
| /* But do make sure we have something in *valp. */ |
| *valp = build_constructor (type, nullptr); |
| CONSTRUCTOR_NO_CLEARING (*valp) = no_zero_init; |
| } |
| } |
| else if (*valp && TREE_CODE (*valp) == CONSTRUCTOR |
| && TREE_CODE (init) == CONSTRUCTOR) |
| { |
| /* An outer ctx->ctor might be pointing to *valp, so replace |
| its contents. */ |
| CONSTRUCTOR_ELTS (*valp) = CONSTRUCTOR_ELTS (init); |
| TREE_CONSTANT (*valp) = TREE_CONSTANT (init); |
| TREE_SIDE_EFFECTS (*valp) = TREE_SIDE_EFFECTS (init); |
| CONSTRUCTOR_NO_CLEARING (*valp) |
| = CONSTRUCTOR_NO_CLEARING (init); |
| } |
| else |
| *valp = init; |
| |
| /* After initialization, 'const' semantics apply to the value of the |
| object. Make a note of this fact by marking the CONSTRUCTOR |
| TREE_READONLY. */ |
| if (TREE_CODE (t) == INIT_EXPR |
| && TREE_CODE (*valp) == CONSTRUCTOR |
| && TYPE_READONLY (type)) |
| { |
| if (INDIRECT_REF_P (target) |
| && (is_this_parameter |
| (tree_strip_nop_conversions (TREE_OPERAND (target, 0))))) |
| /* We've just initialized '*this' (perhaps via the target |
| constructor of a delegating constructor). Leave it up to the |
| caller that set 'this' to set TREE_READONLY appropriately. */ |
| gcc_checking_assert (same_type_ignoring_top_level_qualifiers_p |
| (TREE_TYPE (target), type) || empty_base); |
| else |
| TREE_READONLY (*valp) = true; |
| } |
| |
| /* Update TREE_CONSTANT and TREE_SIDE_EFFECTS on enclosing |
| CONSTRUCTORs, if any. */ |
| bool c = TREE_CONSTANT (init); |
| bool s = TREE_SIDE_EFFECTS (init); |
| if (!indexes->is_empty ()) |
| { |
| tree last = indexes->last (); |
| if (TREE_CODE (last) == REALPART_EXPR |
| || TREE_CODE (last) == IMAGPART_EXPR) |
| { |
| /* And canonicalize COMPLEX_EXPR into COMPLEX_CST if |
| possible. */ |
| tree *cexpr = ctors.last (); |
| if (tree c = const_binop (COMPLEX_EXPR, TREE_TYPE (*cexpr), |
| TREE_OPERAND (*cexpr, 0), |
| TREE_OPERAND (*cexpr, 1))) |
| *cexpr = c; |
| else |
| { |
| TREE_CONSTANT (*cexpr) |
| = (TREE_CONSTANT (TREE_OPERAND (*cexpr, 0)) |
| & TREE_CONSTANT (TREE_OPERAND (*cexpr, 1))); |
| TREE_SIDE_EFFECTS (*cexpr) |
| = (TREE_SIDE_EFFECTS (TREE_OPERAND (*cexpr, 0)) |
| | TREE_SIDE_EFFECTS (TREE_OPERAND (*cexpr, 1))); |
| } |
| c = TREE_CONSTANT (*cexpr); |
| s = TREE_SIDE_EFFECTS (*cexpr); |
| } |
| } |
| if (!c || s || activated_union_member_p) |
| for (tree *elt : ctors) |
| { |
| if (TREE_CODE (*elt) != CONSTRUCTOR) |
| continue; |
| if (!c) |
| TREE_CONSTANT (*elt) = false; |
| if (s) |
| TREE_SIDE_EFFECTS (*elt) = true; |
| /* Clear CONSTRUCTOR_NO_CLEARING since we've activated a member of |
| this union. */ |
| if (TREE_CODE (TREE_TYPE (*elt)) == UNION_TYPE) |
| CONSTRUCTOR_NO_CLEARING (*elt) = false; |
| } |
| |
| if (lval) |
| return target; |
| else |
| return init; |
| } |
| |
| /* Evaluate a ++ or -- expression. */ |
| |
| static tree |
| cxx_eval_increment_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| enum tree_code code = TREE_CODE (t); |
| tree type = TREE_TYPE (t); |
| tree op = TREE_OPERAND (t, 0); |
| tree offset = TREE_OPERAND (t, 1); |
| gcc_assert (TREE_CONSTANT (offset)); |
| |
| /* OFFSET is constant, but perhaps not constant enough. We need to |
| e.g. bash FLOAT_EXPRs to REAL_CSTs. */ |
| offset = fold_simple (offset); |
| |
| /* The operand as an lvalue. */ |
| op = cxx_eval_constant_expression (ctx, op, vc_glvalue, |
| non_constant_p, overflow_p); |
| |
| /* The operand as an rvalue. */ |
| tree val |
| = cxx_eval_constant_expression (ctx, op, vc_prvalue, |
| non_constant_p, overflow_p); |
| /* Don't VERIFY_CONSTANT if this might be dealing with a pointer to |
| a local array in a constexpr function. */ |
| bool ptr = INDIRECT_TYPE_P (TREE_TYPE (val)); |
| if (!ptr) |
| VERIFY_CONSTANT (val); |
| |
| /* The modified value. */ |
| bool inc = (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR); |
| tree mod; |
| if (INDIRECT_TYPE_P (type)) |
| { |
| /* The middle end requires pointers to use POINTER_PLUS_EXPR. */ |
| offset = convert_to_ptrofftype (offset); |
| if (!inc) |
| offset = fold_build1 (NEGATE_EXPR, TREE_TYPE (offset), offset); |
| mod = fold_build2 (POINTER_PLUS_EXPR, type, val, offset); |
| } |
| else if (c_promoting_integer_type_p (type) |
| && !TYPE_UNSIGNED (type) |
| && TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)) |
| { |
| offset = fold_convert (integer_type_node, offset); |
| mod = fold_convert (integer_type_node, val); |
| tree t = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, integer_type_node, |
| mod, offset); |
| mod = fold_convert (type, t); |
| if (TREE_OVERFLOW_P (mod) && !TREE_OVERFLOW_P (t)) |
| TREE_OVERFLOW (mod) = false; |
| } |
| else |
| mod = fold_build2 (inc ? PLUS_EXPR : MINUS_EXPR, type, val, offset); |
| if (!ptr) |
| VERIFY_CONSTANT (mod); |
| |
| /* Storing the modified value. */ |
| tree store = build2_loc (cp_expr_loc_or_loc (t, input_location), |
| MODIFY_EXPR, type, op, mod); |
| mod = cxx_eval_constant_expression (ctx, store, lval, |
| non_constant_p, overflow_p); |
| ggc_free (store); |
| if (*non_constant_p) |
| return t; |
| |
| /* And the value of the expression. */ |
| if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR) |
| /* Prefix ops are lvalues, but the caller might want an rvalue; |
| lval has already been taken into account in the store above. */ |
| return mod; |
| else |
| /* Postfix ops are rvalues. */ |
| return val; |
| } |
| |
| /* Predicates for the meaning of *jump_target. */ |
| |
| static bool |
| returns (tree *jump_target) |
| { |
| return *jump_target |
| && TREE_CODE (*jump_target) == RETURN_EXPR; |
| } |
| |
| static bool |
| breaks (tree *jump_target) |
| { |
| return *jump_target |
| && ((TREE_CODE (*jump_target) == LABEL_DECL |
| && LABEL_DECL_BREAK (*jump_target)) |
| || TREE_CODE (*jump_target) == BREAK_STMT |
| || TREE_CODE (*jump_target) == EXIT_EXPR); |
| } |
| |
| static bool |
| continues (tree *jump_target) |
| { |
| return *jump_target |
| && ((TREE_CODE (*jump_target) == LABEL_DECL |
| && LABEL_DECL_CONTINUE (*jump_target)) |
| || TREE_CODE (*jump_target) == CONTINUE_STMT); |
| |
| } |
| |
| static bool |
| switches (tree *jump_target) |
| { |
| return *jump_target |
| && TREE_CODE (*jump_target) == INTEGER_CST; |
| } |
| |
| /* Subroutine of cxx_eval_statement_list. Determine whether the statement |
| STMT matches *jump_target. If we're looking for a case label and we see |
| the default label, note it in ctx->css_state. */ |
| |
| static bool |
| label_matches (const constexpr_ctx *ctx, tree *jump_target, tree stmt) |
| { |
| switch (TREE_CODE (*jump_target)) |
| { |
| case LABEL_DECL: |
| if (TREE_CODE (stmt) == LABEL_EXPR |
| && LABEL_EXPR_LABEL (stmt) == *jump_target) |
| return true; |
| break; |
| |
| case INTEGER_CST: |
| if (TREE_CODE (stmt) == CASE_LABEL_EXPR) |
| { |
| gcc_assert (ctx->css_state != NULL); |
| if (!CASE_LOW (stmt)) |
| { |
| /* default: should appear just once in a SWITCH_EXPR |
| body (excluding nested SWITCH_EXPR). */ |
| gcc_assert (*ctx->css_state != css_default_seen); |
| /* When evaluating SWITCH_EXPR body for the second time, |
| return true for the default: label. */ |
| if (*ctx->css_state == css_default_processing) |
| return true; |
| *ctx->css_state = css_default_seen; |
| } |
| else if (CASE_HIGH (stmt)) |
| { |
| if (tree_int_cst_le (CASE_LOW (stmt), *jump_target) |
| && tree_int_cst_le (*jump_target, CASE_HIGH (stmt))) |
| return true; |
| } |
| else if (tree_int_cst_equal (*jump_target, CASE_LOW (stmt))) |
| return true; |
| } |
| break; |
| |
| case BREAK_STMT: |
| case CONTINUE_STMT: |
| /* These two are handled directly in cxx_eval_loop_expr by testing |
| breaks (jump_target) or continues (jump_target). */ |
| break; |
| |
| default: |
| gcc_unreachable (); |
| } |
| return false; |
| } |
| |
| /* Evaluate a STATEMENT_LIST for side-effects. Handles various jump |
| semantics, for switch, break, continue, and return. */ |
| |
| static tree |
| cxx_eval_statement_list (const constexpr_ctx *ctx, tree t, |
| bool *non_constant_p, bool *overflow_p, |
| tree *jump_target) |
| { |
| tree local_target; |
| /* In a statement-expression we want to return the last value. |
| For empty statement expression return void_node. */ |
| tree r = void_node; |
| if (!jump_target) |
| { |
| local_target = NULL_TREE; |
| jump_target = &local_target; |
| } |
| for (tree_stmt_iterator i = tsi_start (t); !tsi_end_p (i); ++i) |
| { |
| tree stmt = *i; |
| |
| /* We've found a continue, so skip everything until we reach |
| the label its jumping to. */ |
| if (continues (jump_target)) |
| { |
| if (label_matches (ctx, jump_target, stmt)) |
| /* Found it. */ |
| *jump_target = NULL_TREE; |
| else |
| continue; |
| } |
| if (TREE_CODE (stmt) == DEBUG_BEGIN_STMT) |
| continue; |
| |
| value_cat lval = vc_discard; |
| /* The result of a statement-expression is not wrapped in EXPR_STMT. */ |
| if (tsi_one_before_end_p (i) && TREE_CODE (stmt) != EXPR_STMT) |
| lval = vc_prvalue; |
| |
| r = cxx_eval_constant_expression (ctx, stmt, lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| if (*non_constant_p) |
| break; |
| if (returns (jump_target) || breaks (jump_target)) |
| break; |
| } |
| if (*jump_target && jump_target == &local_target) |
| { |
| /* We aren't communicating the jump to our caller, so give up. We don't |
| need to support evaluation of jumps out of statement-exprs. */ |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (r), |
| "statement is not a constant expression"); |
| *non_constant_p = true; |
| } |
| return r; |
| } |
| |
| /* Evaluate a LOOP_EXPR for side-effects. Handles break and return |
| semantics; continue semantics are covered by cxx_eval_statement_list. */ |
| |
| static tree |
| cxx_eval_loop_expr (const constexpr_ctx *ctx, tree t, |
| bool *non_constant_p, bool *overflow_p, |
| tree *jump_target) |
| { |
| constexpr_ctx new_ctx = *ctx; |
| tree local_target; |
| if (!jump_target) |
| { |
| local_target = NULL_TREE; |
| jump_target = &local_target; |
| } |
| |
| tree body, cond = NULL_TREE, expr = NULL_TREE; |
| int count = 0; |
| switch (TREE_CODE (t)) |
| { |
| case LOOP_EXPR: |
| body = LOOP_EXPR_BODY (t); |
| break; |
| case DO_STMT: |
| body = DO_BODY (t); |
| cond = DO_COND (t); |
| break; |
| case WHILE_STMT: |
| body = WHILE_BODY (t); |
| cond = WHILE_COND (t); |
| count = -1; |
| break; |
| case FOR_STMT: |
| if (FOR_INIT_STMT (t)) |
| cxx_eval_constant_expression (ctx, FOR_INIT_STMT (t), vc_discard, |
| non_constant_p, overflow_p, jump_target); |
| if (*non_constant_p) |
| return NULL_TREE; |
| body = FOR_BODY (t); |
| cond = FOR_COND (t); |
| expr = FOR_EXPR (t); |
| count = -1; |
| break; |
| default: |
| gcc_unreachable (); |
| } |
| auto_vec<tree, 10> save_exprs; |
| new_ctx.save_exprs = &save_exprs; |
| do |
| { |
| if (count != -1) |
| { |
| if (body) |
| cxx_eval_constant_expression (&new_ctx, body, vc_discard, |
| non_constant_p, overflow_p, |
| jump_target); |
| if (breaks (jump_target)) |
| { |
| *jump_target = NULL_TREE; |
| break; |
| } |
| |
| if (TREE_CODE (t) != LOOP_EXPR && continues (jump_target)) |
| *jump_target = NULL_TREE; |
| |
| if (expr) |
| cxx_eval_constant_expression (&new_ctx, expr, vc_prvalue, |
| non_constant_p, overflow_p, |
| jump_target); |
| } |
| |
| if (cond) |
| { |
| tree res |
| = cxx_eval_constant_expression (&new_ctx, cond, vc_prvalue, |
| non_constant_p, overflow_p, |
| jump_target); |
| if (res) |
| { |
| if (verify_constant (res, ctx->quiet, non_constant_p, |
| overflow_p)) |
| break; |
| if (integer_zerop (res)) |
| break; |
| } |
| else |
| gcc_assert (*jump_target); |
| } |
| |
| /* Forget saved values of SAVE_EXPRs and TARGET_EXPRs. */ |
| for (tree save_expr : save_exprs) |
| ctx->global->remove_value (save_expr); |
| save_exprs.truncate (0); |
| |
| if (++count >= constexpr_loop_limit) |
| { |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "%<constexpr%> loop iteration count exceeds limit of %d " |
| "(use %<-fconstexpr-loop-limit=%> to increase the limit)", |
| constexpr_loop_limit); |
| *non_constant_p = true; |
| break; |
| } |
| } |
| while (!returns (jump_target) |
| && !breaks (jump_target) |
| && !continues (jump_target) |
| && (!switches (jump_target) || count == 0) |
| && !*non_constant_p); |
| |
| /* Forget saved values of SAVE_EXPRs and TARGET_EXPRs. */ |
| for (tree save_expr : save_exprs) |
| ctx->global->remove_value (save_expr); |
| |
| return NULL_TREE; |
| } |
| |
| /* Evaluate a SWITCH_EXPR for side-effects. Handles switch and break jump |
| semantics. */ |
| |
| static tree |
| cxx_eval_switch_expr (const constexpr_ctx *ctx, tree t, |
| bool *non_constant_p, bool *overflow_p, |
| tree *jump_target) |
| { |
| tree cond |
| = TREE_CODE (t) == SWITCH_STMT ? SWITCH_STMT_COND (t) : SWITCH_COND (t); |
| cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (cond); |
| *jump_target = cond; |
| |
| tree body |
| = TREE_CODE (t) == SWITCH_STMT ? SWITCH_STMT_BODY (t) : SWITCH_BODY (t); |
| constexpr_ctx new_ctx = *ctx; |
| constexpr_switch_state css = css_default_not_seen; |
| new_ctx.css_state = &css; |
| cxx_eval_constant_expression (&new_ctx, body, vc_discard, |
| non_constant_p, overflow_p, jump_target); |
| if (switches (jump_target) && css == css_default_seen) |
| { |
| /* If the SWITCH_EXPR body has default: label, process it once again, |
| this time instructing label_matches to return true for default: |
| label on switches (jump_target). */ |
| css = css_default_processing; |
| cxx_eval_constant_expression (&new_ctx, body, vc_discard, |
| non_constant_p, overflow_p, jump_target); |
| } |
| if (breaks (jump_target) || switches (jump_target)) |
| *jump_target = NULL_TREE; |
| return NULL_TREE; |
| } |
| |
| /* Find the object of TYPE under initialization in CTX. */ |
| |
| static tree |
| lookup_placeholder (const constexpr_ctx *ctx, value_cat lval, tree type) |
| { |
| if (!ctx) |
| return NULL_TREE; |
| |
| /* Prefer the outermost matching object, but don't cross |
| CONSTRUCTOR_PLACEHOLDER_BOUNDARY constructors. */ |
| if (ctx->ctor && !CONSTRUCTOR_PLACEHOLDER_BOUNDARY (ctx->ctor)) |
| if (tree outer_ob = lookup_placeholder (ctx->parent, lval, type)) |
| return outer_ob; |
| |
| /* We could use ctx->object unconditionally, but using ctx->ctor when we |
| can is a minor optimization. */ |
| if (!lval && ctx->ctor && same_type_p (TREE_TYPE (ctx->ctor), type)) |
| return ctx->ctor; |
| |
| if (!ctx->object) |
| return NULL_TREE; |
| |
| /* Since an object cannot have a field of its own type, we can search outward |
| from ctx->object to find the unique containing object of TYPE. */ |
| tree ob = ctx->object; |
| while (ob) |
| { |
| if (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (ob), type)) |
| break; |
| if (handled_component_p (ob)) |
| ob = TREE_OPERAND (ob, 0); |
| else |
| ob = NULL_TREE; |
| } |
| |
| return ob; |
| } |
| |
| /* Complain about an attempt to evaluate inline assembly. If FUNDEF_P is |
| true, we're checking a constexpr function body. */ |
| |
| static void |
| inline_asm_in_constexpr_error (location_t loc, bool fundef_p) |
| { |
| auto_diagnostic_group d; |
| if (constexpr_error (loc, fundef_p, "inline assembly is not a " |
| "constant expression")) |
| inform (loc, "only unevaluated inline assembly is allowed in a " |
| "%<constexpr%> function in C++20"); |
| } |
| |
| /* We're getting the constant value of DECL in a manifestly constant-evaluated |
| context; maybe complain about that. */ |
| |
| static void |
| maybe_warn_about_constant_value (location_t loc, tree decl) |
| { |
| static bool explained = false; |
| if (cxx_dialect >= cxx17 |
| && warn_interference_size |
| && !OPTION_SET_P (param_destruct_interfere_size) |
| && DECL_CONTEXT (decl) == std_node |
| && id_equal (DECL_NAME (decl), "hardware_destructive_interference_size") |
| && (LOCATION_FILE (input_location) != main_input_filename |
| || module_exporting_p ()) |
| && warning_at (loc, OPT_Winterference_size, "use of %qD", decl) |
| && !explained) |
| { |
| explained = true; |
| inform (loc, "its value can vary between compiler versions or " |
| "with different %<-mtune%> or %<-mcpu%> flags"); |
| inform (loc, "if this use is part of a public ABI, change it to " |
| "instead use a constant variable you define"); |
| inform (loc, "the default value for the current CPU tuning " |
| "is %d bytes", param_destruct_interfere_size); |
| inform (loc, "you can stabilize this value with %<--param " |
| "hardware_destructive_interference_size=%d%>, or disable " |
| "this warning with %<-Wno-interference-size%>", |
| param_destruct_interfere_size); |
| } |
| } |
| |
| /* For element type ELT_TYPE, return the appropriate type of the heap object |
| containing such element(s). COOKIE_SIZE is NULL or the size of cookie |
| in bytes. If COOKIE_SIZE is NULL, return array type |
| ELT_TYPE[FULL_SIZE / sizeof(ELT_TYPE)], otherwise return |
| struct { size_t[COOKIE_SIZE/sizeof(size_t)]; ELT_TYPE[N]; } |
| where N is is computed such that the size of the struct fits into FULL_SIZE. |
| If ARG_SIZE is non-NULL, it is the first argument to the new operator. |
| It should be passed if ELT_TYPE is zero sized type in which case FULL_SIZE |
| will be also 0 and so it is not possible to determine the actual array |
| size. CTX, NON_CONSTANT_P and OVERFLOW_P are used during constant |
| expression evaluation of subexpressions of ARG_SIZE. */ |
| |
| static tree |
| build_new_constexpr_heap_type (const constexpr_ctx *ctx, tree elt_type, |
| tree cookie_size, tree full_size, tree arg_size, |
| bool *non_constant_p, bool *overflow_p) |
| { |
| gcc_assert (cookie_size == NULL_TREE || tree_fits_uhwi_p (cookie_size)); |
| gcc_assert (tree_fits_uhwi_p (full_size)); |
| unsigned HOST_WIDE_INT csz = cookie_size ? tree_to_uhwi (cookie_size) : 0; |
| if (arg_size) |
| { |
| STRIP_NOPS (arg_size); |
| if (cookie_size) |
| { |
| if (TREE_CODE (arg_size) != PLUS_EXPR) |
| arg_size = NULL_TREE; |
| else if (TREE_CODE (TREE_OPERAND (arg_size, 0)) == INTEGER_CST |
| && tree_int_cst_equal (cookie_size, |
| TREE_OPERAND (arg_size, 0))) |
| { |
| arg_size = TREE_OPERAND (arg_size, 1); |
| STRIP_NOPS (arg_size); |
| } |
| else if (TREE_CODE (TREE_OPERAND (arg_size, 1)) == INTEGER_CST |
| && tree_int_cst_equal (cookie_size, |
| TREE_OPERAND (arg_size, 1))) |
| { |
| arg_size = TREE_OPERAND (arg_size, 0); |
| STRIP_NOPS (arg_size); |
| } |
| else |
| arg_size = NULL_TREE; |
| } |
| if (arg_size && TREE_CODE (arg_size) == MULT_EXPR) |
| { |
| tree op0 = TREE_OPERAND (arg_size, 0); |
| tree op1 = TREE_OPERAND (arg_size, 1); |
| if (integer_zerop (op0)) |
| arg_size |
| = cxx_eval_constant_expression (ctx, op1, vc_prvalue, |
| non_constant_p, overflow_p); |
| else if (integer_zerop (op1)) |
| arg_size |
| = cxx_eval_constant_expression (ctx, op0, vc_prvalue, |
| non_constant_p, overflow_p); |
| else |
| arg_size = NULL_TREE; |
| } |
| else |
| arg_size = NULL_TREE; |
| } |
| |
| unsigned HOST_WIDE_INT fsz = tree_to_uhwi (arg_size ? arg_size : full_size); |
| if (!arg_size) |
| { |
| unsigned HOST_WIDE_INT esz = int_size_in_bytes (elt_type); |
| gcc_assert (fsz >= csz); |
| fsz -= csz; |
| if (esz) |
| fsz /= esz; |
| } |
| tree itype2 = build_index_type (size_int (fsz - 1)); |
| if (!cookie_size) |
| return build_cplus_array_type (elt_type, itype2); |
| return build_new_constexpr_heap_type (elt_type, cookie_size, itype2); |
| } |
| |
| /* Attempt to reduce the expression T to a constant value. |
| On failure, issue diagnostic and return error_mark_node. */ |
| /* FIXME unify with c_fully_fold */ |
| /* FIXME overflow_p is too global */ |
| |
| static tree |
| cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t, |
| value_cat lval, |
| bool *non_constant_p, bool *overflow_p, |
| tree *jump_target /* = NULL */) |
| { |
| if (jump_target && *jump_target) |
| { |
| /* If we are jumping, ignore all statements/expressions except those |
| that could have LABEL_EXPR or CASE_LABEL_EXPR in their bodies. */ |
| switch (TREE_CODE (t)) |
| { |
| case BIND_EXPR: |
| case STATEMENT_LIST: |
| case LOOP_EXPR: |
| case COND_EXPR: |
| case IF_STMT: |
| case DO_STMT: |
| case WHILE_STMT: |
| case FOR_STMT: |
| break; |
| case LABEL_EXPR: |
| case CASE_LABEL_EXPR: |
| if (label_matches (ctx, jump_target, t)) |
| /* Found it. */ |
| *jump_target = NULL_TREE; |
| return NULL_TREE; |
| default: |
| return NULL_TREE; |
| } |
| } |
| if (error_operand_p (t)) |
| { |
| *non_constant_p = true; |
| return t; |
| } |
| |
| location_t loc = cp_expr_loc_or_input_loc (t); |
| |
| STRIP_ANY_LOCATION_WRAPPER (t); |
| |
| if (CONSTANT_CLASS_P (t)) |
| { |
| if (TREE_OVERFLOW (t)) |
| { |
| if (!ctx->quiet) |
| permerror (input_location, "overflow in constant expression"); |
| if (!flag_permissive || ctx->quiet) |
| *overflow_p = true; |
| } |
| |
| if (TREE_CODE (t) == INTEGER_CST |
| && TYPE_PTR_P (TREE_TYPE (t)) |
| /* INTEGER_CST with pointer-to-method type is only used |
| for a virtual method in a pointer to member function. |
| Don't reject those. */ |
| && TREE_CODE (TREE_TYPE (TREE_TYPE (t))) != METHOD_TYPE |
| && !integer_zerop (t)) |
| { |
| if (!ctx->quiet) |
| error ("value %qE of type %qT is not a constant expression", |
| t, TREE_TYPE (t)); |
| *non_constant_p = true; |
| } |
| |
| return t; |
| } |
| |
| /* Avoid excessively long constexpr evaluations. */ |
| if (++ctx->global->constexpr_ops_count >= constexpr_ops_limit) |
| { |
| if (!ctx->quiet) |
| error_at (loc, |
| "%<constexpr%> evaluation operation count exceeds limit of " |
| "%wd (use %<-fconstexpr-ops-limit=%> to increase the limit)", |
| constexpr_ops_limit); |
| ctx->global->constexpr_ops_count = INTTYPE_MINIMUM (HOST_WIDE_INT); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| constexpr_ctx new_ctx; |
| tree r = t; |
| |
| tree_code tcode = TREE_CODE (t); |
| switch (tcode) |
| { |
| case RESULT_DECL: |
| if (lval) |
| return t; |
| /* We ask for an rvalue for the RESULT_DECL when indirecting |
| through an invisible reference, or in named return value |
| optimization. */ |
| if (tree v = ctx->global->get_value (t)) |
| return v; |
| else |
| { |
| if (!ctx->quiet) |
| error ("%qE is not a constant expression", t); |
| *non_constant_p = true; |
| } |
| break; |
| |
| case VAR_DECL: |
| if (DECL_HAS_VALUE_EXPR_P (t)) |
| { |
| if (is_normal_capture_proxy (t) |
| && current_function_decl == DECL_CONTEXT (t)) |
| { |
| /* Function parms aren't constexpr within the function |
| definition, so don't try to look at the closure. But if the |
| captured variable is constant, try to evaluate it directly. */ |
| r = DECL_CAPTURED_VARIABLE (t); |
| tree type = TREE_TYPE (t); |
| if (TYPE_REF_P (type) != TYPE_REF_P (TREE_TYPE (r))) |
| { |
| /* Adjust r to match the reference-ness of t. */ |
| if (TYPE_REF_P (type)) |
| r = build_address (r); |
| else |
| r = convert_from_reference (r); |
| } |
| } |
| else |
| r = DECL_VALUE_EXPR (t); |
| return cxx_eval_constant_expression (ctx, r, lval, non_constant_p, |
| overflow_p); |
| } |
| /* fall through */ |
| case CONST_DECL: |
| /* We used to not check lval for CONST_DECL, but darwin.cc uses |
| CONST_DECL for aggregate constants. */ |
| if (lval) |
| return t; |
| else if (t == ctx->object) |
| return ctx->ctor; |
| if (VAR_P (t)) |
| if (tree v = ctx->global->get_value (t)) |
| { |
| r = v; |
| break; |
| } |
| if (ctx->manifestly_const_eval) |
| maybe_warn_about_constant_value (loc, t); |
| if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
| && is_really_empty_class (TREE_TYPE (t), /*ignore_vptr*/false)) |
| { |
| /* If the class is empty, we aren't actually loading anything. */ |
| r = build_constructor (TREE_TYPE (t), NULL); |
| TREE_CONSTANT (r) = true; |
| } |
| else if (ctx->strict) |
| r = decl_really_constant_value (t, /*unshare_p=*/false); |
| else |
| r = decl_constant_value (t, /*unshare_p=*/false); |
| if (TREE_CODE (r) == TARGET_EXPR |
| && TREE_CODE (TARGET_EXPR_INITIAL (r)) == CONSTRUCTOR) |
| r = TARGET_EXPR_INITIAL (r); |
| if (DECL_P (r)) |
| { |
| if (!ctx->quiet) |
| non_const_var_error (loc, r, /*fundef_p*/false); |
| *non_constant_p = true; |
| } |
| break; |
| |
| case DEBUG_BEGIN_STMT: |
| /* ??? It might be nice to retain this information somehow, so |
| as to be able to step into a constexpr function call. */ |
| /* Fall through. */ |
| |
| case FUNCTION_DECL: |
| case TEMPLATE_DECL: |
| case LABEL_DECL: |
| case LABEL_EXPR: |
| case CASE_LABEL_EXPR: |
| case PREDICT_EXPR: |
| return t; |
| |
| case PARM_DECL: |
| if (lval && !TYPE_REF_P (TREE_TYPE (t))) |
| /* glvalue use. */; |
| else if (tree v = ctx->global->get_value (r)) |
| r = v; |
| else if (lval) |
| /* Defer in case this is only used for its type. */; |
| else if (COMPLETE_TYPE_P (TREE_TYPE (t)) |
| && is_really_empty_class (TREE_TYPE (t), /*ignore_vptr*/false)) |
| { |
| /* If the class is empty, we aren't actually loading anything. */ |
| r = build_constructor (TREE_TYPE (t), NULL); |
| TREE_CONSTANT (r) = true; |
| } |
| else |
| { |
| if (!ctx->quiet) |
| error ("%qE is not a constant expression", t); |
| *non_constant_p = true; |
| } |
| break; |
| |
| case CALL_EXPR: |
| case AGGR_INIT_EXPR: |
| r = cxx_eval_call_expression (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case DECL_EXPR: |
| { |
| r = DECL_EXPR_DECL (t); |
| if (TREE_CODE (r) == USING_DECL) |
| { |
| r = void_node; |
| break; |
| } |
| |
| if (VAR_P (r) |
| && (TREE_STATIC (r) |
| || (CP_DECL_THREAD_LOCAL_P (r) && !DECL_REALLY_EXTERN (r))) |
| /* Allow __FUNCTION__ etc. */ |
| && !DECL_ARTIFICIAL (r) |
| && !decl_constant_var_p (r)) |
| { |
| if (!ctx->quiet) |
| { |
| if (CP_DECL_THREAD_LOCAL_P (r)) |
| error_at (loc, "control passes through definition of %qD " |
| "with thread storage duration", r); |
| else |
| error_at (loc, "control passes through definition of %qD " |
| "with static storage duration", r); |
| } |
| *non_constant_p = true; |
| break; |
| } |
| |
| if (AGGREGATE_TYPE_P (TREE_TYPE (r)) |
| || VECTOR_TYPE_P (TREE_TYPE (r))) |
| { |
| new_ctx = *ctx; |
| new_ctx.object = r; |
| new_ctx.ctor = build_constructor (TREE_TYPE (r), NULL); |
| CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
| ctx->global->put_value (r, new_ctx.ctor); |
| ctx = &new_ctx; |
| } |
| |
| if (tree init = DECL_INITIAL (r)) |
| { |
| init = cxx_eval_constant_expression (ctx, init, vc_prvalue, |
| non_constant_p, overflow_p); |
| /* Don't share a CONSTRUCTOR that might be changed. */ |
| init = unshare_constructor (init); |
| /* Remember that a constant object's constructor has already |
| run. */ |
| if (CLASS_TYPE_P (TREE_TYPE (r)) |
| && CP_TYPE_CONST_P (TREE_TYPE (r))) |
| TREE_READONLY (init) = true; |
| ctx->global->put_value (r, init); |
| } |
| else if (ctx == &new_ctx) |
| /* We gave it a CONSTRUCTOR above. */; |
| else |
| ctx->global->put_value (r, NULL_TREE); |
| } |
| break; |
| |
| case TARGET_EXPR: |
| { |
| tree type = TREE_TYPE (t); |
| |
| if (!literal_type_p (type)) |
| { |
| if (!ctx->quiet) |
| { |
| auto_diagnostic_group d; |
| error ("temporary of non-literal type %qT in a " |
| "constant expression", type); |
| explain_non_literal_class (type); |
| } |
| *non_constant_p = true; |
| break; |
| } |
| gcc_checking_assert (!TARGET_EXPR_DIRECT_INIT_P (t)); |
| /* Avoid evaluating a TARGET_EXPR more than once. */ |
| tree slot = TARGET_EXPR_SLOT (t); |
| if (tree v = ctx->global->get_value (slot)) |
| { |
| if (lval) |
| return slot; |
| r = v; |
| break; |
| } |
| if ((AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type))) |
| { |
| /* We're being expanded without an explicit target, so start |
| initializing a new object; expansion with an explicit target |
| strips the TARGET_EXPR before we get here. */ |
| new_ctx = *ctx; |
| /* Link CTX to NEW_CTX so that lookup_placeholder can resolve |
| any PLACEHOLDER_EXPR within the initializer that refers to the |
| former object under construction. */ |
| new_ctx.parent = ctx; |
| new_ctx.ctor = build_constructor (type, NULL); |
| CONSTRUCTOR_NO_CLEARING (new_ctx.ctor) = true; |
| new_ctx.object = slot; |
| ctx->global->put_value (new_ctx.object, new_ctx.ctor); |
| ctx = &new_ctx; |
| } |
| /* Pass vc_prvalue because this indicates |
| initialization of a temporary. */ |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| break; |
| /* Adjust the type of the result to the type of the temporary. */ |
| r = adjust_temp_type (type, r); |
| if (TARGET_EXPR_CLEANUP (t) && !CLEANUP_EH_ONLY (t)) |
| ctx->global->cleanups->safe_push (TARGET_EXPR_CLEANUP (t)); |
| r = unshare_constructor (r); |
| ctx->global->put_value (slot, r); |
| if (ctx->save_exprs) |
| ctx->save_exprs->safe_push (slot); |
| if (lval) |
| return slot; |
| } |
| break; |
| |
| case INIT_EXPR: |
| case MODIFY_EXPR: |
| gcc_assert (jump_target == NULL || *jump_target == NULL_TREE); |
| r = cxx_eval_store_expression (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case SCOPE_REF: |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), |
| lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case RETURN_EXPR: |
| if (TREE_OPERAND (t, 0) != NULL_TREE) |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| lval, |
| non_constant_p, overflow_p); |
| /* FALLTHRU */ |
| case BREAK_STMT: |
| case CONTINUE_STMT: |
| if (jump_target) |
| *jump_target = t; |
| else |
| { |
| /* Can happen with ({ return true; }) && false; passed to |
| maybe_constant_value. There is nothing to jump over in this |
| case, and the bug will be diagnosed later. */ |
| gcc_assert (ctx->quiet); |
| *non_constant_p = true; |
| } |
| break; |
| |
| case SAVE_EXPR: |
| /* Avoid evaluating a SAVE_EXPR more than once. */ |
| if (tree v = ctx->global->get_value (t)) |
| r = v; |
| else |
| { |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), vc_prvalue, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| break; |
| ctx->global->put_value (t, r); |
| if (ctx->save_exprs) |
| ctx->save_exprs->safe_push (t); |
| } |
| break; |
| |
| case TRY_CATCH_EXPR: |
| if (TREE_OPERAND (t, 0) == NULL_TREE) |
| { |
| r = void_node; |
| break; |
| } |
| /* FALLTHRU */ |
| case NON_LVALUE_EXPR: |
| case TRY_BLOCK: |
| case MUST_NOT_THROW_EXPR: |
| case EXPR_STMT: |
| case EH_SPEC_BLOCK: |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| break; |
| |
| case CLEANUP_POINT_EXPR: |
| { |
| auto_vec<tree, 2> cleanups; |
| vec<tree> *prev_cleanups = ctx->global->cleanups; |
| ctx->global->cleanups = &cleanups; |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| ctx->global->cleanups = prev_cleanups; |
| unsigned int i; |
| tree cleanup; |
| /* Evaluate the cleanups. */ |
| FOR_EACH_VEC_ELT_REVERSE (cleanups, i, cleanup) |
| cxx_eval_constant_expression (ctx, cleanup, vc_discard, |
| non_constant_p, overflow_p); |
| } |
| break; |
| |
| case TRY_FINALLY_EXPR: |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| if (!*non_constant_p) |
| /* Also evaluate the cleanup. */ |
| cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 1), vc_discard, |
| non_constant_p, overflow_p); |
| break; |
| |
| case CLEANUP_STMT: |
| r = cxx_eval_constant_expression (ctx, CLEANUP_BODY (t), lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| if (!CLEANUP_EH_ONLY (t) && !*non_constant_p) |
| { |
| iloc_sentinel ils (loc); |
| /* Also evaluate the cleanup. */ |
| cxx_eval_constant_expression (ctx, CLEANUP_EXPR (t), vc_discard, |
| non_constant_p, overflow_p); |
| } |
| break; |
| |
| /* These differ from cxx_eval_unary_expression in that this doesn't |
| check for a constant operand or result; an address can be |
| constant without its operand being, and vice versa. */ |
| case MEM_REF: |
| case INDIRECT_REF: |
| r = cxx_eval_indirect_ref (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case ADDR_EXPR: |
| { |
| tree oldop = TREE_OPERAND (t, 0); |
| tree op = cxx_eval_constant_expression (ctx, oldop, vc_glvalue, |
| non_constant_p, overflow_p); |
| /* Don't VERIFY_CONSTANT here. */ |
| if (*non_constant_p) |
| return t; |
| gcc_checking_assert (TREE_CODE (op) != CONSTRUCTOR); |
| /* This function does more aggressive folding than fold itself. */ |
| r = build_fold_addr_expr_with_type (op, TREE_TYPE (t)); |
| if (TREE_CODE (r) == ADDR_EXPR && TREE_OPERAND (r, 0) == oldop) |
| { |
| ggc_free (r); |
| return t; |
| } |
| break; |
| } |
| |
| case REALPART_EXPR: |
| case IMAGPART_EXPR: |
| if (lval) |
| { |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, |
| non_constant_p, overflow_p); |
| if (r == error_mark_node) |
| ; |
| else if (r == TREE_OPERAND (t, 0) || lval == vc_discard) |
| r = t; |
| else |
| r = fold_build1 (TREE_CODE (t), TREE_TYPE (t), r); |
| break; |
| } |
| /* FALLTHRU */ |
| case CONJ_EXPR: |
| case FIX_TRUNC_EXPR: |
| case FLOAT_EXPR: |
| case NEGATE_EXPR: |
| case ABS_EXPR: |
| case ABSU_EXPR: |
| case BIT_NOT_EXPR: |
| case TRUTH_NOT_EXPR: |
| case FIXED_CONVERT_EXPR: |
| r = cxx_eval_unary_expression (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case SIZEOF_EXPR: |
| r = fold_sizeof_expr (t); |
| /* In a template, fold_sizeof_expr may merely create a new SIZEOF_EXPR, |
| which could lead to an infinite recursion. */ |
| if (TREE_CODE (r) != SIZEOF_EXPR) |
| r = cxx_eval_constant_expression (ctx, r, lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| else |
| { |
| *non_constant_p = true; |
| gcc_assert (ctx->quiet); |
| } |
| |
| break; |
| |
| case COMPOUND_EXPR: |
| { |
| /* check_return_expr sometimes wraps a TARGET_EXPR in a |
| COMPOUND_EXPR; don't get confused. Also handle EMPTY_CLASS_EXPR |
| introduced by build_call_a. */ |
| tree op0 = TREE_OPERAND (t, 0); |
| tree op1 = TREE_OPERAND (t, 1); |
| STRIP_NOPS (op1); |
| if ((TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) |
| || TREE_CODE (op1) == EMPTY_CLASS_EXPR) |
| r = cxx_eval_constant_expression (ctx, op0, |
| lval, non_constant_p, overflow_p, |
| jump_target); |
| else |
| { |
| /* Check that the LHS is constant and then discard it. */ |
| cxx_eval_constant_expression (ctx, op0, vc_discard, |
| non_constant_p, overflow_p, |
| jump_target); |
| if (*non_constant_p) |
| return t; |
| op1 = TREE_OPERAND (t, 1); |
| r = cxx_eval_constant_expression (ctx, op1, |
| lval, non_constant_p, overflow_p, |
| jump_target); |
| } |
| } |
| break; |
| |
| case POINTER_PLUS_EXPR: |
| case POINTER_DIFF_EXPR: |
| case PLUS_EXPR: |
| case MINUS_EXPR: |
| case MULT_EXPR: |
| case TRUNC_DIV_EXPR: |
| case CEIL_DIV_EXPR: |
| case FLOOR_DIV_EXPR: |
| case ROUND_DIV_EXPR: |
| case TRUNC_MOD_EXPR: |
| case CEIL_MOD_EXPR: |
| case ROUND_MOD_EXPR: |
| case RDIV_EXPR: |
| case EXACT_DIV_EXPR: |
| case MIN_EXPR: |
| case MAX_EXPR: |
| case LSHIFT_EXPR: |
| case RSHIFT_EXPR: |
| case LROTATE_EXPR: |
| case RROTATE_EXPR: |
| case BIT_IOR_EXPR: |
| case BIT_XOR_EXPR: |
| case BIT_AND_EXPR: |
| case TRUTH_XOR_EXPR: |
| case LT_EXPR: |
| case LE_EXPR: |
| case GT_EXPR: |
| case GE_EXPR: |
| case EQ_EXPR: |
| case NE_EXPR: |
| case SPACESHIP_EXPR: |
| case UNORDERED_EXPR: |
| case ORDERED_EXPR: |
| case UNLT_EXPR: |
| case UNLE_EXPR: |
| case UNGT_EXPR: |
| case UNGE_EXPR: |
| case UNEQ_EXPR: |
| case LTGT_EXPR: |
| case RANGE_EXPR: |
| case COMPLEX_EXPR: |
| r = cxx_eval_binary_expression (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| /* fold can introduce non-IF versions of these; still treat them as |
| short-circuiting. */ |
| case TRUTH_AND_EXPR: |
| case TRUTH_ANDIF_EXPR: |
| r = cxx_eval_logical_expression (ctx, t, boolean_false_node, |
| boolean_true_node, |
| non_constant_p, overflow_p); |
| break; |
| |
| case TRUTH_OR_EXPR: |
| case TRUTH_ORIF_EXPR: |
| r = cxx_eval_logical_expression (ctx, t, boolean_true_node, |
| boolean_false_node, |
| non_constant_p, overflow_p); |
| break; |
| |
| case ARRAY_REF: |
| r = cxx_eval_array_reference (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case COMPONENT_REF: |
| if (is_overloaded_fn (t)) |
| { |
| /* We can only get here in checking mode via |
| build_non_dependent_expr, because any expression that |
| calls or takes the address of the function will have |
| pulled a FUNCTION_DECL out of the COMPONENT_REF. */ |
| gcc_checking_assert (ctx->quiet || errorcount); |
| *non_constant_p = true; |
| return t; |
| } |
| r = cxx_eval_component_reference (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case BIT_FIELD_REF: |
| r = cxx_eval_bit_field_ref (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case COND_EXPR: |
| case IF_STMT: |
| if (jump_target && *jump_target) |
| { |
| tree orig_jump = *jump_target; |
| tree arg = ((TREE_CODE (t) != IF_STMT || TREE_OPERAND (t, 1)) |
| ? TREE_OPERAND (t, 1) : void_node); |
| /* When jumping to a label, the label might be either in the |
| then or else blocks, so process then block first in skipping |
| mode first, and if we are still in the skipping mode at its end, |
| process the else block too. */ |
| r = cxx_eval_constant_expression (ctx, arg, lval, non_constant_p, |
| overflow_p, jump_target); |
| /* It's possible that we found the label in the then block. But |
| it could have been followed by another jumping statement, e.g. |
| say we're looking for case 1: |
| if (cond) |
| { |
| // skipped statements |
| case 1:; // clears up *jump_target |
| return 1; // and sets it to a RETURN_EXPR |
| } |
| else { ... } |
| in which case we need not go looking to the else block. |
| (goto is not allowed in a constexpr function.) */ |
| if (*jump_target == orig_jump) |
| { |
| arg = ((TREE_CODE (t) != IF_STMT || TREE_OPERAND (t, 2)) |
| ? TREE_OPERAND (t, 2) : void_node); |
| r = cxx_eval_constant_expression (ctx, arg, lval, non_constant_p, |
| overflow_p, jump_target); |
| } |
| break; |
| } |
| r = cxx_eval_conditional_expression (ctx, t, lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| break; |
| case VEC_COND_EXPR: |
| r = cxx_eval_vector_conditional_expression (ctx, t, non_constant_p, |
| overflow_p); |
| break; |
| |
| case CONSTRUCTOR: |
| if (TREE_CONSTANT (t) && reduced_constant_expression_p (t)) |
| { |
| /* Don't re-process a constant CONSTRUCTOR. */ |
| verify_constructor_flags (t); |
| if (TREE_CONSTANT (t)) |
| return t; |
| } |
| r = cxx_eval_bare_aggregate (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case VEC_INIT_EXPR: |
| /* We can get this in a defaulted constructor for a class with a |
| non-static data member of array type. Either the initializer will |
| be NULL, meaning default-initialization, or it will be an lvalue |
| or xvalue of the same type, meaning direct-initialization from the |
| corresponding member. */ |
| r = cxx_eval_vec_init (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case VEC_PERM_EXPR: |
| r = cxx_eval_trinary_expression (ctx, t, lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case PAREN_EXPR: |
| gcc_assert (!REF_PARENTHESIZED_P (t)); |
| /* A PAREN_EXPR resulting from __builtin_assoc_barrier has no effect in |
| constant expressions since it's unaffected by -fassociative-math. */ |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), lval, |
| non_constant_p, overflow_p); |
| break; |
| |
| case NOP_EXPR: |
| if (REINTERPRET_CAST_P (t)) |
| { |
| if (!ctx->quiet) |
| error_at (loc, |
| "%<reinterpret_cast%> is not a constant expression"); |
| *non_constant_p = true; |
| return t; |
| } |
| /* FALLTHROUGH. */ |
| case CONVERT_EXPR: |
| case VIEW_CONVERT_EXPR: |
| case UNARY_PLUS_EXPR: |
| { |
| tree oldop = TREE_OPERAND (t, 0); |
| |
| tree op = cxx_eval_constant_expression (ctx, oldop, |
| lval, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| tree type = TREE_TYPE (t); |
| |
| if (VOID_TYPE_P (type)) |
| return void_node; |
| |
| if (TREE_CODE (t) == CONVERT_EXPR |
| && ARITHMETIC_TYPE_P (type) |
| && INDIRECT_TYPE_P (TREE_TYPE (op)) |
| && ctx->manifestly_const_eval) |
| { |
| if (!ctx->quiet) |
| error_at (loc, |
| "conversion from pointer type %qT to arithmetic type " |
| "%qT in a constant expression", TREE_TYPE (op), type); |
| *non_constant_p = true; |
| return t; |
| } |
| |
| /* [expr.const]: a conversion from type cv void* to a pointer-to-object |
| type cannot be part of a core constant expression as a resolution to |
| DR 1312. */ |
| if (TYPE_PTROB_P (type) |
| && TYPE_PTR_P (TREE_TYPE (op)) |
| && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (op))) |
| /* Inside a call to std::construct_at or to |
| std::allocator<T>::{,de}allocate, we permit casting from void* |
| because that is compiler-generated code. */ |
| && !is_std_construct_at (ctx->call) |
| && !is_std_allocator_allocate (ctx->call)) |
| { |
| /* Likewise, don't error when casting from void* when OP is |
| &heap uninit and similar. */ |
| tree sop = tree_strip_nop_conversions (op); |
| if (TREE_CODE (sop) == ADDR_EXPR |
| && VAR_P (TREE_OPERAND (sop, 0)) |
| && DECL_ARTIFICIAL (TREE_OPERAND (sop, 0))) |
| /* OK */; |
| else |
| { |
| if (!ctx->quiet) |
| error_at (loc, "cast from %qT is not allowed", |
| TREE_TYPE (op)); |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| |
| if (TREE_CODE (op) == PTRMEM_CST && !TYPE_PTRMEM_P (type)) |
| op = cplus_expand_constant (op); |
| |
| if (TREE_CODE (op) == PTRMEM_CST && tcode == NOP_EXPR) |
| { |
| if (!same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (op)) |
| && !can_convert_qual (type, op)) |
| op = cplus_expand_constant (op); |
| return cp_fold_convert (type, op); |
| } |
| |
| if (INDIRECT_TYPE_P (type) && TREE_CODE (op) == INTEGER_CST) |
| { |
| if (integer_zerop (op)) |
| { |
| if (TYPE_REF_P (type)) |
| { |
| if (!ctx->quiet) |
| error_at (loc, "dereferencing a null pointer"); |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| else |
| { |
| /* This detects for example: |
| reinterpret_cast<void*>(sizeof 0) |
| */ |
| if (!ctx->quiet) |
| error_at (loc, "%<reinterpret_cast<%T>(%E)%> is not " |
| "a constant expression", |
| type, op); |
| *non_constant_p = true; |
| return t; |
| } |
| } |
| |
| if (INDIRECT_TYPE_P (type) |
| && TREE_CODE (op) == NOP_EXPR |
| && TREE_TYPE (op) == ptr_type_node |
| && TREE_CODE (TREE_OPERAND (op, 0)) == ADDR_EXPR |
| && VAR_P (TREE_OPERAND (TREE_OPERAND (op, 0), 0)) |
| && (DECL_NAME (TREE_OPERAND (TREE_OPERAND (op, 0), |
| 0)) == heap_uninit_identifier |
| || DECL_NAME (TREE_OPERAND (TREE_OPERAND (op, 0), |
| 0)) == heap_vec_uninit_identifier)) |
| { |
| tree var = TREE_OPERAND (TREE_OPERAND (op, 0), 0); |
| tree var_size = TYPE_SIZE_UNIT (TREE_TYPE (var)); |
| tree elt_type = TREE_TYPE (type); |
| tree cookie_size = NULL_TREE; |
| tree arg_size = NULL_TREE; |
| if (TREE_CODE (elt_type) == RECORD_TYPE |
| && TYPE_NAME (elt_type) == heap_identifier) |
| { |
| tree fld1 = TYPE_FIELDS (elt_type); |
| tree fld2 = DECL_CHAIN (fld1); |
| elt_type = TREE_TYPE (TREE_TYPE (fld2)); |
| cookie_size = TYPE_SIZE_UNIT (TREE_TYPE (fld1)); |
| } |
| DECL_NAME (var) |
| = (DECL_NAME (var) == heap_uninit_identifier |
| ? heap_identifier : heap_vec_identifier); |
| /* For zero sized elt_type, try to recover how many outer_nelts |
| it should have. */ |
| if ((cookie_size ? tree_int_cst_equal (var_size, cookie_size) |
| : integer_zerop (var_size)) |
| && !int_size_in_bytes (elt_type) |
| && TREE_CODE (oldop) == CALL_EXPR |
| && call_expr_nargs (oldop) >= 1) |
| if (tree fun = get_function_named_in_call (oldop)) |
| if (cxx_replaceable_global_alloc_fn (fun) |
| && IDENTIFIER_NEW_OP_P (DECL_NAME (fun))) |
| arg_size = CALL_EXPR_ARG (oldop, 0); |
| TREE_TYPE (var) |
| = build_new_constexpr_heap_type (ctx, elt_type, cookie_size, |
| var_size, arg_size, |
| non_constant_p, overflow_p); |
| TREE_TYPE (TREE_OPERAND (op, 0)) |
| = build_pointer_type (TREE_TYPE (var)); |
| } |
| |
| if (op == oldop && tcode != UNARY_PLUS_EXPR) |
| /* We didn't fold at the top so we could check for ptr-int |
| conversion. */ |
| return fold (t); |
| |
| tree sop; |
| |
| /* Handle an array's bounds having been deduced after we built |
| the wrapping expression. */ |
| if (same_type_ignoring_tlq_and_bounds_p (type, TREE_TYPE (op))) |
| r = op; |
| else if (sop = tree_strip_nop_conversions (op), |
| sop != op && (same_type_ignoring_tlq_and_bounds_p |
| (type, TREE_TYPE (sop)))) |
| r = sop; |
| else if (tcode == UNARY_PLUS_EXPR) |
| r = fold_convert (TREE_TYPE (t), op); |
| else |
| r = fold_build1 (tcode, type, op); |
| |
| /* Conversion of an out-of-range value has implementation-defined |
| behavior; the language considers it different from arithmetic |
| overflow, which is undefined. */ |
| if (TREE_OVERFLOW_P (r) && !TREE_OVERFLOW_P (op)) |
| TREE_OVERFLOW (r) = false; |
| } |
| break; |
| |
| case EXCESS_PRECISION_EXPR: |
| { |
| tree oldop = TREE_OPERAND (t, 0); |
| |
| tree op = cxx_eval_constant_expression (ctx, oldop, |
| lval, |
| non_constant_p, overflow_p); |
| if (*non_constant_p) |
| return t; |
| r = fold_convert (TREE_TYPE (t), op); |
| break; |
| } |
| |
| case EMPTY_CLASS_EXPR: |
| /* Handle EMPTY_CLASS_EXPR produced by build_call_a by lowering |
| it to an appropriate CONSTRUCTOR. */ |
| return build_constructor (TREE_TYPE (t), NULL); |
| |
| case STATEMENT_LIST: |
| new_ctx = *ctx; |
| new_ctx.ctor = new_ctx.object = NULL_TREE; |
| return cxx_eval_statement_list (&new_ctx, t, |
| non_constant_p, overflow_p, jump_target); |
| |
| case BIND_EXPR: |
| return cxx_eval_constant_expression (ctx, BIND_EXPR_BODY (t), |
| lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| |
| case PREINCREMENT_EXPR: |
| case POSTINCREMENT_EXPR: |
| case PREDECREMENT_EXPR: |
| case POSTDECREMENT_EXPR: |
| return cxx_eval_increment_expression (ctx, t, |
| lval, non_constant_p, overflow_p); |
| |
| case LAMBDA_EXPR: |
| case NEW_EXPR: |
| case VEC_NEW_EXPR: |
| case DELETE_EXPR: |
| case VEC_DELETE_EXPR: |
| case THROW_EXPR: |
| case MODOP_EXPR: |
| /* GCC internal stuff. */ |
| case VA_ARG_EXPR: |
| case NON_DEPENDENT_EXPR: |
| case BASELINK: |
| case OFFSET_REF: |
| if (!ctx->quiet) |
| error_at (loc, "expression %qE is not a constant expression", t); |
| *non_constant_p = true; |
| break; |
| |
| case OBJ_TYPE_REF: |
| /* Virtual function lookup. We don't need to do anything fancy. */ |
| return cxx_eval_constant_expression (ctx, OBJ_TYPE_REF_EXPR (t), |
| lval, non_constant_p, overflow_p); |
| |
| case PLACEHOLDER_EXPR: |
| /* Use of the value or address of the current object. */ |
| if (tree ctor = lookup_placeholder (ctx, lval, TREE_TYPE (t))) |
| { |
| if (TREE_CODE (ctor) == CONSTRUCTOR) |
| return ctor; |
| else |
| return cxx_eval_constant_expression (ctx, ctor, lval, |
| non_constant_p, overflow_p); |
| } |
| /* A placeholder without a referent. We can get here when |
| checking whether NSDMIs are noexcept, or in massage_init_elt; |
| just say it's non-constant for now. */ |
| gcc_assert (ctx->quiet); |
| *non_constant_p = true; |
| break; |
| |
| case EXIT_EXPR: |
| { |
| tree cond = TREE_OPERAND (t, 0); |
| cond = cxx_eval_constant_expression (ctx, cond, vc_prvalue, |
| non_constant_p, overflow_p); |
| VERIFY_CONSTANT (cond); |
| if (integer_nonzerop (cond)) |
| *jump_target = t; |
| } |
| break; |
| |
| case GOTO_EXPR: |
| if (breaks (&TREE_OPERAND (t, 0)) |
| || continues (&TREE_OPERAND (t, 0))) |
| *jump_target = TREE_OPERAND (t, 0); |
| else |
| { |
| gcc_assert (cxx_dialect >= cxx23); |
| if (!ctx->quiet) |
| error_at (loc, "%<goto%> is not a constant expression"); |
| *non_constant_p = true; |
| } |
| break; |
| |
| case LOOP_EXPR: |
| case DO_STMT: |
| case WHILE_STMT: |
| case FOR_STMT: |
| cxx_eval_loop_expr (ctx, t, |
| non_constant_p, overflow_p, jump_target); |
| break; |
| |
| case SWITCH_EXPR: |
| case SWITCH_STMT: |
| cxx_eval_switch_expr (ctx, t, |
| non_constant_p, overflow_p, jump_target); |
| break; |
| |
| case REQUIRES_EXPR: |
| /* It's possible to get a requires-expression in a constant |
| expression. For example: |
| |
| template<typename T> concept bool C() { |
| return requires (T t) { t; }; |
| } |
| |
| template<typename T> requires !C<T>() void f(T); |
| |
| Normalization leaves f with the associated constraint |
| '!requires (T t) { ... }' which is not transformed into |
| a constraint. */ |
| if (!processing_template_decl) |
| return evaluate_requires_expr (t); |
| else |
| *non_constant_p = true; |
| return t; |
| |
| case ANNOTATE_EXPR: |
| r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0), |
| lval, |
| non_constant_p, overflow_p, |
| jump_target); |
| break; |
| |
| case USING_STMT: |
| r = void_node; |
| break; |
| |
| case ASSERTION_STMT: |
| case PRECONDITION_STMT: |
| case POSTCONDITION_STMT: |
| { |
| contract_semantic semantic = get_contract_semantic (t); |
| if (semantic == CCS_IGNORE) |
| break; |
| |
| if (!cxx_eval_assert (ctx, CONTRACT_CONDITION (t), |
| G_("contract predicate is false in " |
| "constant expression"), |
| EXPR_LOCATION (t), checked_contract_p (semantic), |
| non_constant_p, overflow_p)) |
| *non_constant_p = true; |
| r = void_node; |
| } |
| break; |
| |
| case TEMPLATE_ID_EXPR: |
| { |
| /* We can evaluate template-id that refers to a concept only if |
| the template arguments are non-dependent. */ |
| tree id = unpack_concept_check (t); |
| tree tmpl = TREE_OPERAND (id, 0); |
| if (!concept_definition_p (tmpl)) |
| internal_error ("unexpected template-id %qE", t); |
| |
| if (function_concept_p (tmpl)) |
| { |
| if (!ctx->quiet) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "function concept must be called"); |
| r = error_mark_node; |
| break; |
| } |
| |
| if (!value_dependent_expression_p (t) |
| && !uid_sensitive_constexpr_evaluation_p ()) |
| r = evaluate_concept_check (t); |
| else |
| *non_constant_p = true; |
| |
| break; |
| } |
| |
| case ASM_EXPR: |
| if (!ctx->quiet) |
| inline_asm_in_constexpr_error (loc, /*constexpr_fundef_p*/false); |
| *non_constant_p = true; |
| return t; |
| |
| case BIT_CAST_EXPR: |
| if (lval) |
| { |
| if (!ctx->quiet) |
| error_at (EXPR_LOCATION (t), |
| "address of a call to %qs is not a constant expression", |
| "__builtin_bit_cast"); |
| *non_constant_p = true; |
| return t; |
| } |
| r = cxx_eval_bit_cast (ctx, t, non_constant_p, overflow_p); |
| break; |
| |
| case OMP_PARALLEL: |
| case OMP_TASK: |
| case OMP_FOR: |
| case OMP_SIMD: |
| case OMP_DISTRIBUTE: |
| case OMP_TASKLOOP: |
| case OMP_LOOP: |
| case OMP_TEAMS: |
| case OMP_TARGET_DATA: |
| case OMP_TARGET: |
| case OMP_SECTIONS: |
| case OMP_ORDERED: |
| case OMP_CRITICAL: |
| case OMP_SINGLE: |
| case OMP_SCAN: |
| case OMP_SCOPE: |
| case OMP_SECTION: |
| case OMP_MASTER: |
| case OMP_MASKED: |
| case OMP_TASKGROUP: |
| case OMP_TARGET_UPDATE: |
| case OMP_TARGET_ENTER_DATA: |
| case OMP_TARGET_EXIT_DATA: |
| case OMP_ATOMIC: |
| case OMP_ATOMIC_READ: |
| case OMP_ATOMIC_CAPTURE_OLD: |
| case OMP_ATOMIC_CAPTURE_NEW: |
| case OMP_DEPOBJ: |
| case OACC_PARALLEL: |
| case OACC_KERNELS: |
| case OACC_SERIAL: |
| case OACC_DATA: |
| case OACC_HOST_DATA: |
| case OACC_LOOP: |
| case OACC_CACHE: |
| case OACC_DECLARE: |
| case OACC_ENTER_DATA: |
| case OACC_EXIT_DATA: |
| case OACC_UPDATE: |
| if (!ctx->quiet) |
| error_at (EXPR_LOCATION (t), |
| "statement is not a constant expression"); |
| *non_constant_p = true; |
| break; |
| |
| default: |
| if (STATEMENT_CODE_P (TREE_CODE (t))) |
| { |
| /* This function doesn't know how to deal with pre-genericize |
| statements; this can only happen with statement-expressions, |
| so for now just fail. */ |
| if (!ctx->quiet) |
| error_at (EXPR_LOCATION (t), |
| "statement is not a constant expression"); |
| } |
| else |
| internal_error ("unexpected expression %qE of kind %s", t, |
| get_tree_code_name (TREE_CODE (t))); |
| *non_constant_p = true; |
| break; |
| } |
| |
| if (r == error_mark_node) |
| *non_constant_p = true; |
| |
| if (*non_constant_p) |
| return t; |
| else |
| return r; |
| } |
| |
| /* P0859: A function is needed for constant evaluation if it is a constexpr |
| function that is named by an expression ([basic.def.odr]) that is |
| potentially constant evaluated. |
| |
| So we need to instantiate any constexpr functions mentioned by the |
| expression even if the definition isn't needed for evaluating the |
| expression. */ |
| |
| static tree |
| instantiate_cx_fn_r (tree *tp, int *walk_subtrees, void */*data*/) |
| { |
| if (TREE_CODE (*tp) == FUNCTION_DECL |
| && DECL_DECLARED_CONSTEXPR_P (*tp) |
| && !DECL_INITIAL (*tp) |
| && !trivial_fn_p (*tp) |
| && DECL_TEMPLOID_INSTANTIATION (*tp) |
| && !uid_sensitive_constexpr_evaluation_p ()) |
| { |
| ++function_depth; |
| instantiate_decl (*tp, /*defer_ok*/false, /*expl_inst*/false); |
| --function_depth; |
| } |
| else if (TREE_CODE (*tp) == CALL_EXPR |
| || TREE_CODE (*tp) == AGGR_INIT_EXPR) |
| { |
| if (EXPR_HAS_LOCATION (*tp)) |
| input_location = EXPR_LOCATION (*tp); |
| } |
| |
| if (!EXPR_P (*tp)) |
| *walk_subtrees = 0; |
| |
| return NULL_TREE; |
| } |
| |
| static void |
| instantiate_constexpr_fns (tree t) |
| { |
| location_t loc = input_location; |
| cp_walk_tree_without_duplicates (&t, instantiate_cx_fn_r, NULL); |
| input_location = loc; |
| } |
| |
| /* Look for heap variables in the expression *TP. */ |
| |
| static tree |
| find_heap_var_refs (tree *tp, int *walk_subtrees, void */*data*/) |
| { |
| if (VAR_P (*tp) |
| && (DECL_NAME (*tp) == heap_uninit_identifier |
| || DECL_NAME (*tp) == heap_identifier |
| || DECL_NAME (*tp) == heap_vec_uninit_identifier |
| || DECL_NAME (*tp) == heap_vec_identifier |
| || DECL_NAME (*tp) == heap_deleted_identifier)) |
| return *tp; |
| |
| if (TYPE_P (*tp)) |
| *walk_subtrees = 0; |
| return NULL_TREE; |
| } |
| |
| /* Find immediate function decls in *TP if any. */ |
| |
| static tree |
| find_immediate_fndecl (tree *tp, int */*walk_subtrees*/, void */*data*/) |
| { |
| if (TREE_CODE (*tp) == FUNCTION_DECL && DECL_IMMEDIATE_FUNCTION_P (*tp)) |
| return *tp; |
| if (TREE_CODE (*tp) == PTRMEM_CST |
| && TREE_CODE (PTRMEM_CST_MEMBER (*tp)) == FUNCTION_DECL |
| && DECL_IMMEDIATE_FUNCTION_P (PTRMEM_CST_MEMBER (*tp))) |
| return PTRMEM_CST_MEMBER (*tp); |
| return NULL_TREE; |
| } |
| |
| /* T has TREE_CONSTANT set but has been deemed not a valid C++ constant |
| expression. Return a version of T that has TREE_CONSTANT cleared. */ |
| |
| static tree |
| mark_non_constant (tree t) |
| { |
| gcc_checking_assert (TREE_CONSTANT (t)); |
| |
| /* This isn't actually constant, so unset TREE_CONSTANT. |
| Don't clear TREE_CONSTANT on ADDR_EXPR, as the middle-end requires |
| it to be set if it is invariant address, even when it is not |
| a valid C++ constant expression. Wrap it with a NOP_EXPR |
| instead. */ |
| if (EXPR_P (t) && TREE_CODE (t) != ADDR_EXPR) |
| t = copy_node (t); |
| else if (TREE_CODE (t) == CONSTRUCTOR) |
| t = build1 (VIEW_CONVERT_EXPR, TREE_TYPE (t), t); |
| else |
| t = build_nop (TREE_TYPE (t), t); |
| TREE_CONSTANT (t) = false; |
| return t; |
| } |
| |
| /* ALLOW_NON_CONSTANT is false if T is required to be a constant expression. |
| STRICT has the same sense as for constant_value_1: true if we only allow |
| conforming C++ constant expressions, or false if we want a constant value |
| even if it doesn't conform. |
| MANIFESTLY_CONST_EVAL is true if T is manifestly const-evaluated as |
| per P0595 even when ALLOW_NON_CONSTANT is true. |
| CONSTEXPR_DTOR is true when evaluating the dtor of a constexpr variable. |
| OBJECT must be non-NULL in that case. */ |
| |
| static tree |
| cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, |
| bool strict = true, |
| bool manifestly_const_eval = false, |
| bool constexpr_dtor = false, |
| tree object = NULL_TREE) |
| { |
| auto_timevar time (TV_CONSTEXPR); |
| |
| bool non_constant_p = false; |
| bool overflow_p = false; |
| |
| if (BRACE_ENCLOSED_INITIALIZER_P (t)) |
| { |
| gcc_checking_assert (allow_non_constant); |
| return t; |
| } |
| |
| constexpr_global_ctx global_ctx; |
| constexpr_ctx ctx = { &global_ctx, NULL, NULL, NULL, NULL, NULL, NULL, |
| allow_non_constant, strict, |
| manifestly_const_eval || !allow_non_constant }; |
| |
| /* Turn off -frounding-math for manifestly constant evaluation. */ |
| warning_sentinel rm (flag_rounding_math, ctx.manifestly_const_eval); |
| tree type = initialized_type (t); |
| tree r = t; |
| bool is_consteval = false; |
| if (VOID_TYPE_P (type)) |
| { |
| if (constexpr_dtor) |
| /* Used for destructors of array elements. */ |
| type = TREE_TYPE (object); |
| else |
| { |
| if (cxx_dialect < cxx20) |
| return t; |
| if (TREE_CODE (t) != CALL_EXPR && TREE_CODE (t) != AGGR_INIT_EXPR) |
| return t; |
| /* Calls to immediate functions returning void need to be |
| evaluated. */ |
| tree fndecl = cp_get_callee_fndecl_nofold (t); |
| if (fndecl == NULL_TREE || !DECL_IMMEDIATE_FUNCTION_P (fndecl)) |
| return t; |
| else |
| is_consteval = true; |
| } |
| } |
| else if (cxx_dialect >= cxx20 |
| && (TREE_CODE (t) == CALL_EXPR |
| || TREE_CODE (t) == AGGR_INIT_EXPR |
| || TREE_CODE (t) == TARGET_EXPR)) |
| { |
| /* For non-concept checks, determine if it is consteval. */ |
| if (!concept_check_p (t)) |
| { |
| tree x = t; |
| if (TREE_CODE (x) == TARGET_EXPR) |
| x = TARGET_EXPR_INITIAL (x); |
| tree fndecl = cp_get_callee_fndecl_nofold (x); |
| if (fndecl && DECL_IMMEDIATE_FUNCTION_P (fndecl)) |
| is_consteval = true; |
| } |
| } |
| if (AGGREGATE_TYPE_P (type) || VECTOR_TYPE_P (type)) |
| { |
| /* In C++14 an NSDMI can participate in aggregate initialization, |
| and can refer to the address of the object being initialized, so |
| we need to pass in the relevant VAR_DECL if we want to do the |
| evaluation in a single pass. The evaluation will dynamically |
| update ctx.values for the VAR_DECL. We use the same strategy |
| for C++11 constexpr constructors that refer to the object being |
| initialized. */ |
| if (constexpr_dtor) |
| { |
| gcc_assert (object && VAR_P (object)); |
| gcc_assert (DECL_DECLARED_CONSTEXPR_P (object)); |
| gcc_assert (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (object)); |
| if (error_operand_p (DECL_INITIAL (object))) |
| return t; |
| ctx.ctor = unshare_expr (DECL_INITIAL (object)); |
| TREE_READONLY (ctx.ctor) = false; |
| /* Temporarily force decl_really_constant_value to return false |
| for it, we want to use ctx.ctor for the current value instead. */ |
| DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (object) = false; |
| } |
| else |
| { |
| ctx.ctor = build_constructor (type, NULL); |
| CONSTRUCTOR_NO_CLEARING (ctx.ctor) = true; |
| } |
| if (!object) |
| { |
| if (TREE_CODE (t) == TARGET_EXPR) |
| object = TARGET_EXPR_SLOT (t); |
| else if (TREE_CODE (t) == AGGR_INIT_EXPR) |
| object = AGGR_INIT_EXPR_SLOT (t); |
| } |
| ctx.object = object; |
| if (object) |
| gcc_assert (same_type_ignoring_top_level_qualifiers_p |
| (type, TREE_TYPE (object))); |
| if (object && DECL_P (object)) |
| global_ctx.put_value (object, ctx.ctor); |
| if (TREE_CODE (r) == TARGET_EXPR) |
| /* Avoid creating another CONSTRUCTOR when we expand the |
| TARGET_EXPR. */ |
| r = TARGET_EXPR_INITIAL (r); |
| } |
| |
| auto_vec<tree, 16> cleanups; |
| global_ctx.cleanups = &cleanups; |
| |
| if (manifestly_const_eval) |
| instantiate_constexpr_fns (r); |
| r = cxx_eval_constant_expression (&ctx, r, vc_prvalue, |
| &non_constant_p, &overflow_p); |
| |
| if (!constexpr_dtor) |
| verify_constant (r, allow_non_constant, &non_constant_p, &overflow_p); |
| else |
| DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (object) = true; |
| |
| unsigned int i; |
| tree cleanup; |
| /* Evaluate the cleanups. */ |
| FOR_EACH_VEC_ELT_REVERSE (cleanups, i, cleanup) |
| cxx_eval_constant_expression (&ctx, cleanup, vc_discard, |
| &non_constant_p, &overflow_p); |
| |
| /* Mutable logic is a bit tricky: we want to allow initialization of |
| constexpr variables with mutable members, but we can't copy those |
| members to another constexpr variable. */ |
| if (TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_MUTABLE_POISON (r)) |
| { |
| if (!allow_non_constant) |
| error ("%qE is not a constant expression because it refers to " |
| "mutable subobjects of %qT", t, type); |
| non_constant_p = true; |
| } |
| |
| if (TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_NO_CLEARING (r)) |
| { |
| if (!allow_non_constant) |
| error ("%qE is not a constant expression because it refers to " |
| "an incompletely initialized variable", t); |
| TREE_CONSTANT (r) = false; |
| non_constant_p = true; |
| } |
| |
| if (!global_ctx.heap_vars.is_empty ()) |
| { |
| tree heap_var = cp_walk_tree_without_duplicates (&r, find_heap_var_refs, |
| NULL); |
| unsigned int i; |
| if (heap_var) |
| { |
| if (!allow_non_constant && !non_constant_p) |
| error_at (DECL_SOURCE_LOCATION (heap_var), |
| "%qE is not a constant expression because it refers to " |
| "a result of %<operator new%>", t); |
| r = t; |
| non_constant_p = true; |
| } |
| FOR_EACH_VEC_ELT (global_ctx.heap_vars, i, heap_var) |
| { |
| if (DECL_NAME (heap_var) != heap_deleted_identifier) |
| { |
| if (!allow_non_constant && !non_constant_p) |
| error_at (DECL_SOURCE_LOCATION (heap_var), |
| "%qE is not a constant expression because allocated " |
| "storage has not been deallocated", t); |
| r = t; |
| non_constant_p = true; |
| } |
| varpool_node::get (heap_var)->remove (); |
| } |
| } |
| |
| /* Check that immediate invocation does not return an expression referencing |
| any immediate function decls. */ |
| if (is_consteval || in_immediate_context ()) |
| if (tree immediate_fndecl |
| = cp_walk_tree_without_duplicates (&r, find_immediate_fndecl, |
| NULL)) |
| { |
| if (!allow_non_constant && !non_constant_p) |
| error_at (cp_expr_loc_or_input_loc (t), |
| "immediate evaluation returns address of immediate " |
| "function %qD", immediate_fndecl); |
| r = t; |
| non_constant_p = true; |
| } |
| |
| if (non_constant_p) |
| /* If we saw something bad, go back to our argument. The wrapping below is |
| only for the cases of TREE_CONSTANT argument or overflow. */ |
| r = t; |
| |
| if (!non_constant_p && overflow_p) |
| non_constant_p = true; |
| |
| /* Unshare the result. */ |
| bool should_unshare = true; |
| if (r == t || (TREE_CODE (t) == TARGET_EXPR |
| && TARGET_EXPR_INITIAL (t) == r)) |
| should_unshare = false; |
| |
| if (non_constant_p && !allow_non_constant) |
| return error_mark_node; |
| else if (constexpr_dtor) |
| return r; |
| else if (non_constant_p && TREE_CONSTANT (r)) |
| r = mark_non_constant (r); |
| else if (non_constant_p) |
| return t; |
| |
| if (should_unshare) |
| r = unshare_expr (r); |
| |
| if (TREE_CODE (r) == CONSTRUCTOR && CLASS_TYPE_P (TREE_TYPE (r))) |
| { |
| r = adjust_temp_type (type, r); |
| if (TREE_CODE (t) == TARGET_EXPR |
| && TARGET_EXPR_INITIAL (t) == r) |
| return t; |
| else if (TREE_CODE (t) == CONSTRUCTOR || TREE_CODE (t) == CALL_EXPR) |
| /* Don't add a TARGET_EXPR if our argument didn't have one. */; |
| else if (TREE_CODE (t) == TARGET_EXPR && TARGET_EXPR_CLEANUP (t)) |
| r = get_target_expr (r); |
| else |
| { |
| r = get_target_expr (r, tf_warning_or_error | tf_no_cleanup); |
| TREE_CONSTANT (r) = true; |
| } |
| } |
| |
| /* Remember the original location if that wouldn't need a wrapper. */ |
| if (location_t loc = EXPR_LOCATION (t)) |
| protected_set_expr_location (r, loc); |
| |
| return r; |
| } |
| |
| /* If T represents a constant expression returns its reduced value. |
| Otherwise return error_mark_node. */ |
| |
| tree |
| cxx_constant_value (tree t, tree decl /* = NULL_TREE */, |
| tsubst_flags_t complain /* = tf_error */) |
| { |
| bool sfinae = !(complain & tf_error); |
| tree r = cxx_eval_outermost_constant_expr (t, sfinae, true, true, false, decl); |
| if (sfinae && !TREE_CONSTANT (r)) |
| r = error_mark_node; |
| return r; |
| } |
| |
| /* Like cxx_constant_value, but used for evaluation of constexpr destructors |
| of constexpr variables. The actual initializer of DECL is not modified. */ |
| |
| void |
| cxx_constant_dtor (tree t, tree decl) |
| { |
| cxx_eval_outermost_constant_expr (t, false, true, true, true, decl); |
| } |
| |
| /* Helper routine for fold_simple function. Either return simplified |
| expression T, otherwise NULL_TREE. |
| In contrast to cp_fully_fold, and to maybe_constant_value, we try to fold |
| even if we are within template-declaration. So be careful on call, as in |
| such case types can be undefined. */ |
| |
| static tree |
| fold_simple_1 (tree t) |
| { |
| tree op1; |
| enum tree_code code = TREE_CODE (t); |
| |
| switch (code) |
| { |
| case INTEGER_CST: |
| case REAL_CST: |
| case VECTOR_CST: |
| case FIXED_CST: |
| case COMPLEX_CST: |
| return t; |
| |
| case SIZEOF_EXPR: |
| return fold_sizeof_expr (t); |
| |
| case ABS_EXPR: |
| case ABSU_EXPR: |
| case CONJ_EXPR: |
| case REALPART_EXPR: |
| case IMAGPART_EXPR: |
| case NEGATE_EXPR: |
| case BIT_NOT_EXPR: |
| case TRUTH_NOT_EXPR: |
| case VIEW_CONVERT_EXPR: |
| CASE_CONVERT: |
| case FLOAT_EXPR: |
| case FIX_TRUNC_EXPR: |
| case FIXED_CONVERT_EXPR: |
| case ADDR_SPACE_CONVERT_EXPR: |
| |
| op1 = TREE_OPERAND (t, 0); |
| |
| t = const_unop (code, TREE_TYPE (t), op1); |
| if (!t) |
| return NULL_TREE; |
| |
| if (CONVERT_EXPR_CODE_P (code) |
| && TREE_OVERFLOW_P (t) && !TREE_OVERFLOW_P (op1)) |
| TREE_OVERFLOW (t) = false; |
| return t; |
| |
| default: |
| return NULL_TREE; |
| } |
| } |
| |
| /* If T is a simple constant expression, returns its simplified value. |
| Otherwise returns T. In contrast to maybe_constant_value we |
| simplify only few operations on constant-expressions, and we don't |
| try to simplify constexpressions. */ |
| |
| tree |
| fold_simple (tree t) |
| { |
| if (processing_template_decl) |
| return t; |
| |
| tree r = fold_simple_1 (t); |
| if (r) |
| return r; |
| |
| return t; |
| } |
| |
| /* If T is a constant expression, returns its reduced value. |
| Otherwise, if T does not have TREE_CONSTANT set, returns T. |
| Otherwise, returns a version of T without TREE_CONSTANT. |
| MANIFESTLY_CONST_EVAL is true if T is manifestly const-evaluated |
| as per P0595. */ |
| |
| static GTY((deletable)) hash_map<tree, tree> *cv_cache; |
| |
| tree |
| maybe_constant_value (tree t, tree decl /* = NULL_TREE */, |
| bool manifestly_const_eval /* = false */) |
| { |
| tree r; |
| |
| if (!is_nondependent_constant_expression (t)) |
| { |
| if (TREE_OVERFLOW_P (t) |
| || (!processing_template_decl && TREE_CONSTANT (t))) |
| t = mark_non_constant (t); |
| return t; |
| } |
| else if (CONSTANT_CLASS_P (t)) |
| /* No caching or evaluation needed. */ |
| return t; |
| |
| if (manifestly_const_eval) |
| return cxx_eval_outermost_constant_expr (t, true, true, true, false, decl); |
| |
| if (cv_cache == NULL) |
| cv_cache = hash_map<tree, tree>::create_ggc (101); |
| if (tree *cached = cv_cache->get (t)) |
| { |
| r = *cached; |
| if (r != t) |
| { |
| /* Clear processing_template_decl for sake of break_out_target_exprs; |
| entries in the cv_cache are non-templated. */ |
| processing_template_decl_sentinel ptds; |
| |
| r = break_out_target_exprs (r, /*clear_loc*/true); |
| protected_set_expr_location (r, EXPR_LOCATION (t)); |
| } |
| return r; |
| } |
| |
| /* Don't evaluate an unevaluated operand. */ |
| if (cp_unevaluated_operand) |
| return t; |
| |
| uid_sensitive_constexpr_evaluation_checker c; |
| r = cxx_eval_outermost_constant_expr (t, true, true, false, false, decl); |
| gcc_checking_assert (r == t |
| || CONVERT_EXPR_P (t) |
| || TREE_CODE (t) == VIEW_CONVERT_EXPR |
| || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) |
| || !cp_tree_equal (r, t)); |
| if (!c.evaluation_restricted_p ()) |
| cv_cache->put (t, r); |
| return r; |
| } |
| |
| /* Dispose of the whole CV_CACHE. */ |
| |
| static void |
| clear_cv_cache (void) |
| { |
| if (cv_cache != NULL) |
| cv_cache->empty (); |
| } |
| |
| /* Dispose of the whole CV_CACHE and FOLD_CACHE. */ |
| |
| void |
| clear_cv_and_fold_caches () |
| { |
| clear_cv_cache (); |
| clear_fold_cache (); |
| } |
| |
| /* Internal function handling expressions in templates for |
| fold_non_dependent_expr and fold_non_dependent_init. |
| |
| If we're in a template, but T isn't value dependent, simplify |
| it. We're supposed to treat: |
| |
| template <typename T> void f(T[1 + 1]); |
| template <typename T> void f(T[2]); |
| |
| as two declarations of the same function, for example. */ |
| |
| static tree |
| fold_non_dependent_expr_template (tree t, tsubst_flags_t complain, |
| bool manifestly_const_eval, |
| tree object) |
| { |
| gcc_assert (processing_template_decl); |
| |
| if (is_nondependent_constant_expression (t)) |
| { |
| processing_template_decl_sentinel s; |
| t = instantiate_non_dependent_expr_internal (t, complain); |
| |
| if (type_unknown_p (t) || BRACE_ENCLOSED_INITIALIZER_P (t)) |
| { |
| if (TREE_OVERFLOW_P (t)) |
| { |
| t = build_nop (TREE_TYPE (t), t); |
| TREE_CONSTANT (t) = false; |
| } |
| return t; |
| } |
| |
| if (cp_unevaluated_operand && !manifestly_const_eval) |
| return t; |
| |
| tree r = cxx_eval_outermost_constant_expr (t, true, true, |
| manifestly_const_eval, |
| false, object); |
| /* cp_tree_equal looks through NOPs, so allow them. */ |
| gcc_checking_assert (r == t |
| || CONVERT_EXPR_P (t) |
| || TREE_CODE (t) == VIEW_CONVERT_EXPR |
| || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) |
| || !cp_tree_equal (r, t)); |
| return r; |
| } |
| else if (TREE_OVERFLOW_P (t)) |
| { |
| t = build_nop (TREE_TYPE (t), t); |
| TREE_CONSTANT (t) = false; |
| } |
| |
| return t; |
| } |
| |
| /* Like maybe_constant_value but first fully instantiate the argument. |
| |
| Note: this is equivalent to instantiate_non_dependent_expr (t, complain) |
| followed by maybe_constant_value but is more efficient, |
| because it calls instantiation_dependent_expression_p and |
| potential_constant_expression at most once. |
| The manifestly_const_eval argument is passed to maybe_constant_value. |
| |
| Callers should generally pass their active complain, or if they are in a |
| non-template, diagnosing context, they can use the default of |
| tf_warning_or_error. Callers that might be within a template context, don't |
| have a complain parameter, and aren't going to remember the result for long |
| (e.g. null_ptr_cst_p), can pass tf_none and deal with error_mark_node |
| appropriately. */ |
| |
| tree |
| fold_non_dependent_expr (tree t, |
| tsubst_flags_t complain /* = tf_warning_or_error */, |
| bool manifestly_const_eval /* = false */, |
| tree object /* = NULL_TREE */) |
| { |
| if (t == NULL_TREE) |
| return NULL_TREE; |
| |
| if (processing_template_decl) |
| return fold_non_dependent_expr_template (t, complain, |
| manifestly_const_eval, object); |
| |
| return maybe_constant_value (t, object, manifestly_const_eval); |
| } |
| |
| /* Like fold_non_dependent_expr, but if EXPR couldn't be folded to a constant, |
| return the original expression. */ |
| |
| tree |
| maybe_fold_non_dependent_expr (tree expr, |
| tsubst_flags_t complain/*=tf_warning_or_error*/) |
| { |
| tree t = fold_non_dependent_expr (expr, complain); |
| if (t && TREE_CONSTANT (t)) |
| return t; |
| |
| return expr; |
| } |
| |
| /* Like maybe_constant_init but first fully instantiate the argument. */ |
| |
| tree |
| fold_non_dependent_init (tree t, |
| tsubst_flags_t complain /*=tf_warning_or_error*/, |
| bool manifestly_const_eval /*=false*/, |
| tree object /* = NULL_TREE */) |
| { |
| if (t == NULL_TREE) |
| return NULL_TREE; |
| |
| if (processing_template_decl) |
| { |
| t = fold_non_dependent_expr_template (t, complain, |
| manifestly_const_eval, object); |
| /* maybe_constant_init does this stripping, so do it here too. */ |
| if (TREE_CODE (t) == TARGET_EXPR) |
| { |
| tree init = TARGET_EXPR_INITIAL (t); |
| if (TREE_CODE (init) == CONSTRUCTOR) |
| t = init; |
| } |
| return t; |
| } |
| |
| return maybe_constant_init (t, object, manifestly_const_eval); |
| } |
| |
| /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather |
| than wrapped in a TARGET_EXPR. |
| ALLOW_NON_CONSTANT is false if T is required to be a constant expression. |
| MANIFESTLY_CONST_EVAL is true if T is manifestly const-evaluated as |
| per P0595 even when ALLOW_NON_CONSTANT is true. */ |
| |
| static tree |
| maybe_constant_init_1 (tree t, tree decl, bool allow_non_constant, |
| bool manifestly_const_eval) |
| { |
| if (!t) |
| return t; |
| if (TREE_CODE (t) == EXPR_STMT) |
| t = TREE_OPERAND (t, 0); |
| if (TREE_CODE (t) == CONVERT_EXPR |
| && VOID_TYPE_P (TREE_TYPE (t))) |
| t = TREE_OPERAND (t, 0); |
| if (TREE_CODE (t) == INIT_EXPR) |
| t = TREE_OPERAND (t, 1); |
| if (TREE_CODE (t) == TARGET_EXPR) |
| t = TARGET_EXPR_INITIAL (t); |
| if (!is_nondependent_static_init_expression (t)) |
| /* Don't try to evaluate it. */; |
| else if (CONSTANT_CLASS_P (t) && allow_non_constant) |
| /* No evaluation needed. */; |
| else |
| { |
| /* [basic.start.static] allows constant-initialization of variables with |
| static or thread storage duration even if it isn't required, but we |
| shouldn't bend the rules the same way for automatic variables. */ |
| bool is_static = (decl && DECL_P (decl) |
| && (TREE_STATIC (decl) || DECL_EXTERNAL (decl))); |
| t = cxx_eval_outermost_constant_expr (t, allow_non_constant, !is_static, |
| manifestly_const_eval, false, decl); |
| } |
| if (TREE_CODE (t) == TARGET_EXPR) |
| { |
| tree init = TARGET_EXPR_INITIAL (t); |
| if (TREE_CODE (init) == CONSTRUCTOR) |
| t = init; |
| } |
| return t; |
| } |
| |
| /* Wrapper for maybe_constant_init_1 which permits non constants. */ |
| |
| tree |
| maybe_constant_init (tree t, tree decl, bool manifestly_const_eval) |
| { |
| return maybe_constant_init_1 (t, decl, true, manifestly_const_eval); |
| } |
| |
| /* Wrapper for maybe_constant_init_1 which does not permit non constants. */ |
| |
| tree |
| cxx_constant_init (tree t, tree decl) |
| { |
| return maybe_constant_init_1 (t, decl, false, true); |
| } |
| |
| #if 0 |
| /* FIXME see ADDR_EXPR section in potential_constant_expression_1. */ |
| /* Return true if the object referred to by REF has automatic or thread |
| local storage. */ |
| |
| enum { ck_ok, ck_bad, ck_unknown }; |
| static int |
| check_automatic_or_tls (tree ref) |
| { |
| machine_mode mode; |
| poly_int64 bitsize, bitpos; |
| tree offset; |
| int volatilep = 0, unsignedp = 0; |
| tree decl = get_inner_reference (ref, &bitsize, &bitpos, &offset, |
| &mode, &unsignedp, &volatilep, false); |
| duration_kind dk; |
| |
| /* If there isn't a decl in the middle, we don't know the linkage here, |
| and this isn't a constant expression anyway. */ |
| if (!DECL_P (decl)) |
| return ck_unknown; |
| dk = decl_storage_duration (decl); |
| return (dk == dk_auto || dk == dk_thread) ? ck_bad : ck_ok; |
| } |
| #endif |
| |
| /* Data structure for passing data from potential_constant_expression_1 |
| to check_for_return_continue via cp_walk_tree. */ |
| struct check_for_return_continue_data { |
| hash_set<tree> *pset; |
| tree continue_stmt; |
| tree break_stmt; |
| }; |
| |
| /* Helper function for potential_constant_expression_1 SWITCH_STMT handling, |
| called through cp_walk_tree. Return the first RETURN_EXPR found, or note |
| the first CONTINUE_STMT and/or BREAK_STMT if RETURN_EXPR is not found. */ |
| static tree |
| check_for_return_continue (tree *tp, int *walk_subtrees, void *data) |
| { |
| tree t = *tp, s, b; |
| check_for_return_continue_data *d = (check_for_return_continue_data *) data; |
| switch (TREE_CODE (t)) |
| { |
| case RETURN_EXPR: |
| return t; |
| |
| case CONTINUE_STMT: |
| if (d->continue_stmt == NULL_TREE) |
| d->continue_stmt = t; |
| break; |
| |
| case BREAK_STMT: |
| if (d->break_stmt == NULL_TREE) |
| d->break_stmt = t; |
| break; |
| |
| #define RECUR(x) \ |
| if (tree r = cp_walk_tree (&x, check_for_return_continue, data, \ |
| d->pset)) \ |
| return r |
| |
| /* For loops, walk subtrees manually, so that continue stmts found |
| inside of the bodies of the loops are ignored. */ |
| case DO_STMT: |
| *walk_subtrees = 0; |
| RECUR (DO_COND (t)); |
| s = d->continue_stmt; |
| b = d->break_stmt; |
| RECUR (DO_BODY (t)); |
| d->continue_stmt = s; |
| d->break_stmt = b; |
| break; |
| |
| case WHILE_STMT: |
| *walk_subtrees = 0; |
| RECUR (WHILE_COND (t)); |
| s = d->continue_stmt; |
| b = d->break_stmt; |
| RECUR (WHILE_BODY (t)); |
| d->continue_stmt = s; |
| d->break_stmt = b; |
| break; |
| |
| case FOR_STMT: |
| *walk_subtrees = 0; |
| RECUR (FOR_INIT_STMT (t)); |
| RECUR (FOR_COND (t)); |
| RECUR (FOR_EXPR (t)); |
| s = d->continue_stmt; |
| b = d->break_stmt; |
| RECUR (FOR_BODY (t)); |
| d->continue_stmt = s; |
| d->break_stmt = b; |
| break; |
| |
| case RANGE_FOR_STMT: |
| *walk_subtrees = 0; |
| RECUR (RANGE_FOR_EXPR (t)); |
| s = d->continue_stmt; |
| b = d->break_stmt; |
| RECUR (RANGE_FOR_BODY (t)); |
| d->continue_stmt = s; |
| d->break_stmt = b; |
| break; |
| |
| case SWITCH_STMT: |
| *walk_subtrees = 0; |
| RECUR (SWITCH_STMT_COND (t)); |
| b = d->break_stmt; |
| RECUR (SWITCH_STMT_BODY (t)); |
| d->break_stmt = b; |
| break; |
| #undef RECUR |
| |
| case STATEMENT_LIST: |
| case CONSTRUCTOR: |
| break; |
| |
| default: |
| if (!EXPR_P (t)) |
| *walk_subtrees = 0; |
| break; |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* Return true if T denotes a potentially constant expression. Issue |
| diagnostic as appropriate under control of FLAGS. If WANT_RVAL is true, |
| an lvalue-rvalue conversion is implied. If NOW is true, we want to |
| consider the expression in the current context, independent of constexpr |
| substitution. If FUNDEF_P is true, we're checking a constexpr function body |
| and hard errors should not be reported by constexpr_error. |
| |
| C++0x [expr.const] used to say |
| |
| 6 An expression is a potential constant expression if it is |
| a constant expression where all occurrences of function |
| parameters are replaced by arbitrary constant expressions |
| of the appropriate type. |
| |
| 2 A conditional expression is a constant expression unless it |
| involves one of the following as a potentially evaluated |
| subexpression (3.2), but subexpressions of logical AND (5.14), |
| logical OR (5.15), and conditional (5.16) operations that are |
| not evaluated are not considered. */ |
| |
| static bool |
| potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
| bool fundef_p, tsubst_flags_t flags, |
| tree *jump_target) |
| { |
| #define RECUR(T,RV) \ |
| potential_constant_expression_1 ((T), (RV), strict, now, fundef_p, flags, \ |
| jump_target) |
| |
| enum { any = false, rval = true }; |
| int i; |
| tree tmp; |
| |
| if (t == error_mark_node) |
| return false; |
| if (t == NULL_TREE) |
| return true; |
| location_t loc = cp_expr_loc_or_input_loc (t); |
| |
| if (*jump_target) |
| /* If we are jumping, ignore everything. This is simpler than the |
| cxx_eval_constant_expression handling because we only need to be |
| conservatively correct, and we don't necessarily have a constant value |
| available, so we don't bother with switch tracking. */ |
| return true; |
| |
| if (TREE_THIS_VOLATILE (t) && want_rval) |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "lvalue-to-rvalue conversion of " |
| "a volatile lvalue %qE with type %qT", t, |
| TREE_TYPE (t)); |
| return false; |
| } |
| if (CONSTANT_CLASS_P (t)) |
| return true; |
| if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_TYPED) |
| && TREE_TYPE (t) == error_mark_node) |
| return false; |
| |
| switch (TREE_CODE (t)) |
| { |
| case FUNCTION_DECL: |
| case BASELINK: |
| case TEMPLATE_DECL: |
| case OVERLOAD: |
| case TEMPLATE_ID_EXPR: |
| case LABEL_DECL: |
| case CASE_LABEL_EXPR: |
| case PREDICT_EXPR: |
| case CONST_DECL: |
| case SIZEOF_EXPR: |
| case ALIGNOF_EXPR: |
| case OFFSETOF_EXPR: |
| case NOEXCEPT_EXPR: |
| case TEMPLATE_PARM_INDEX: |
| case TRAIT_EXPR: |
| case IDENTIFIER_NODE: |
| case USERDEF_LITERAL: |
| /* We can see a FIELD_DECL in a pointer-to-member expression. */ |
| case FIELD_DECL: |
| case RESULT_DECL: |
| case USING_DECL: |
| case USING_STMT: |
| case PLACEHOLDER_EXPR: |
| case REQUIRES_EXPR: |
| case STATIC_ASSERT: |
| case DEBUG_BEGIN_STMT: |
| return true; |
| |
| case RETURN_EXPR: |
| if (!RECUR (TREE_OPERAND (t, 0), any)) |
| return false; |
| /* FALLTHROUGH */ |
| |
| case BREAK_STMT: |
| case CONTINUE_STMT: |
| *jump_target = t; |
| return true; |
| |
| case PARM_DECL: |
| if (now && want_rval) |
| { |
| tree type = TREE_TYPE (t); |
| if ((processing_template_decl && !COMPLETE_TYPE_P (type)) |
| || dependent_type_p (type) |
| || is_really_empty_class (type, /*ignore_vptr*/false)) |
| /* An empty class has no data to read. */ |
| return true; |
| if (flags & tf_error) |
| constexpr_error (input_location, fundef_p, |
| "%qE is not a constant expression", t); |
| return false; |
| } |
| return true; |
| |
| case AGGR_INIT_EXPR: |
| case CALL_EXPR: |
| /* -- an invocation of a function other than a constexpr function |
| or a constexpr constructor. */ |
| { |
| tree fun = get_function_named_in_call (t); |
| const int nargs = call_expr_nargs (t); |
| i = 0; |
| |
| if (fun == NULL_TREE) |
| { |
| /* Reset to allow the function to continue past the end |
| of the block below. Otherwise return early. */ |
| bool bail = true; |
| |
| if (TREE_CODE (t) == CALL_EXPR |
| && CALL_EXPR_FN (t) == NULL_TREE) |
| switch (CALL_EXPR_IFN (t)) |
| { |
| /* These should be ignored, they are optimized away from |
| constexpr functions. */ |
| case IFN_UBSAN_NULL: |
| case IFN_UBSAN_BOUNDS: |
| case IFN_UBSAN_VPTR: |
| case IFN_FALLTHROUGH: |
| case IFN_ASSUME: |
| return true; |
| |
| case IFN_ADD_OVERFLOW: |
| case IFN_SUB_OVERFLOW: |
| case IFN_MUL_OVERFLOW: |
| case IFN_LAUNDER: |
| case IFN_VEC_CONVERT: |
| bail = false; |
| break; |
| |
| default: |
| break; |
| } |
| |
| if (bail) |
| { |
| /* fold_call_expr can't do anything with IFN calls. */ |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, |
| "call to internal function %qE", t); |
| return false; |
| } |
| } |
| |
| if (fun && is_overloaded_fn (fun)) |
| { |
| if (TREE_CODE (fun) == FUNCTION_DECL) |
| { |
| if (builtin_valid_in_constant_expr_p (fun)) |
| return true; |
| if (!maybe_constexpr_fn (fun) |
| /* Allow any built-in function; if the expansion |
| isn't constant, we'll deal with that then. */ |
| && !fndecl_built_in_p (fun) |
| /* In C++20, replaceable global allocation functions |
| are constant expressions. */ |
| && (!cxx_replaceable_global_alloc_fn (fun) |
| || TREE_CODE (t) != CALL_EXPR |
| || (!CALL_FROM_NEW_OR_DELETE_P (t) |
| && (current_function_decl == NULL_TREE |
| || !is_std_allocator_allocate |
| (current_function_decl)))) |
| /* Allow placement new in std::construct_at. */ |
| && (!cxx_placement_new_fn (fun) |
| || TREE_CODE (t) != CALL_EXPR |
| || current_function_decl == NULL_TREE |
| || !is_std_construct_at (current_function_decl)) |
| && !cxx_dynamic_cast_fn_p (fun)) |
| { |
| if ((flags & tf_error) |
| && constexpr_error (loc, fundef_p, |
| "call to non-%<constexpr%> " |
| "function %qD", fun)) |
| explain_invalid_constexpr_fn (fun); |
| return false; |
| } |
| /* A call to a non-static member function takes the address |
| of the object as the first argument. But in a constant |
| expression the address will be folded away, so look |
| through it now. */ |
| if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fun) |
| && !DECL_CONSTRUCTOR_P (fun)) |
| { |
| tree x = get_nth_callarg (t, 0); |
| if (is_this_parameter (x)) |
| return true; |
| /* Don't require an immediately constant value, as |
| constexpr substitution might not use the value. */ |
| bool sub_now = false; |
| if (!potential_constant_expression_1 (x, rval, strict, |
| sub_now, fundef_p, |
| flags, jump_target)) |
| return false; |
| i = 1; |
| } |
| } |
| else |
| { |
| if (!RECUR (fun, true)) |
| return false; |
| fun = get_first_fn (fun); |
| } |
| /* Skip initial arguments to base constructors. */ |
| if (DECL_BASE_CONSTRUCTOR_P (fun)) |
| i = num_artificial_parms_for (fun); |
| fun = DECL_ORIGIN (fun); |
| } |
| else if (fun) |
| { |
| if (RECUR (fun, rval)) |
| /* Might end up being a constant function pointer. */; |
| else |
| return false; |
| } |
| for (; i < nargs; ++i) |
| { |
| tree x = get_nth_callarg (t, i); |
| /* In a template, reference arguments haven't been converted to |
| REFERENCE_TYPE and we might not even know if the parameter |
| is a reference, so accept lvalue constants too. */ |
| bool rv = processing_template_decl ? any : rval; |
| /* Don't require an immediately constant value, as constexpr |
| substitution might not use the value of the argument. */ |
| bool sub_now = false; |
| if (!potential_constant_expression_1 (x, rv, strict, |
| sub_now, fundef_p, flags, |
| jump_target)) |
| return false; |
| } |
| return true; |
| } |
| |
| case NON_LVALUE_EXPR: |
| /* -- an lvalue-to-rvalue conversion (4.1) unless it is applied to |
| -- an lvalue of integral type that refers to a non-volatile |
| const variable or static data member initialized with |
| constant expressions, or |
| |
| -- an lvalue of literal type that refers to non-volatile |
| object defined with constexpr, or that refers to a |
| sub-object of such an object; */ |
| return RECUR (TREE_OPERAND (t, 0), rval); |
| |
| case EXCESS_PRECISION_EXPR: |
| return RECUR (TREE_OPERAND (t, 0), rval); |
| |
| case VAR_DECL: |
| if (DECL_HAS_VALUE_EXPR_P (t)) |
| { |
| if (now && is_normal_capture_proxy (t)) |
| { |
| /* -- in a lambda-expression, a reference to this or to a |
| variable with automatic storage duration defined outside that |
| lambda-expression, where the reference would be an |
| odr-use. */ |
| |
| if (want_rval) |
| /* Since we're doing an lvalue-rvalue conversion, this might |
| not be an odr-use, so evaluate the variable directly. */ |
| return RECUR (DECL_CAPTURED_VARIABLE (t), rval); |
| |
| if (flags & tf_error) |
| { |
| tree cap = DECL_CAPTURED_VARIABLE (t); |
| if (constexpr_error (input_location, fundef_p, |
| "lambda capture of %qE is not a " |
| "constant expression", cap) |
| && decl_constant_var_p (cap)) |
| inform (input_location, "because it is used as a glvalue"); |
| } |
| return false; |
| } |
| /* Treat __PRETTY_FUNCTION__ inside a template function as |
| potentially-constant. */ |
| else if (DECL_PRETTY_FUNCTION_P (t) |
| && DECL_VALUE_EXPR (t) == error_mark_node) |
| return true; |
| return RECUR (DECL_VALUE_EXPR (t), rval); |
| } |
| if (want_rval |
| && !var_in_maybe_constexpr_fn (t) |
| && !type_dependent_expression_p (t) |
| && !decl_maybe_constant_var_p (t) |
| && (strict |
| || !CP_TYPE_CONST_NON_VOLATILE_P (TREE_TYPE (t)) |
| || (DECL_INITIAL (t) |
| && !DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t))) |
| && COMPLETE_TYPE_P (TREE_TYPE (t)) |
| && !is_really_empty_class (TREE_TYPE (t), /*ignore_vptr*/false)) |
| { |
| if (flags & tf_error) |
| non_const_var_error (loc, t, fundef_p); |
| return false; |
| } |
| return true; |
| |
| case NOP_EXPR: |
| if (REINTERPRET_CAST_P (t)) |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "%<reinterpret_cast%> is not a " |
| "constant expression"); |
| return false; |
| } |
| /* FALLTHRU */ |
| case CONVERT_EXPR: |
| case VIEW_CONVERT_EXPR: |
| /* -- a reinterpret_cast. FIXME not implemented, and this rule |
| may change to something more specific to type-punning (DR 1312). */ |
| { |
| tree from = TREE_OPERAND (t, 0); |
| if (location_wrapper_p (t)) |
| { |
| iloc_sentinel ils = loc; |
| return (RECUR (from, want_rval)); |
| } |
| if (INDIRECT_TYPE_P (TREE_TYPE (t))) |
| { |
| STRIP_ANY_LOCATION_WRAPPER (from); |
| if (TREE_CODE (from) == INTEGER_CST |
| && !integer_zerop (from)) |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, |
| "%<reinterpret_cast%> from integer to " |
| "pointer"); |
| return false; |
| } |
| } |
| return (RECUR (from, TREE_CODE (t) != VIEW_CONVERT_EXPR)); |
| } |
| |
| case ADDRESSOF_EXPR: |
| /* This is like ADDR_EXPR, except it won't form pointer-to-member. */ |
| t = TREE_OPERAND (t, 0); |
| goto handle_addr_expr; |
| |
| case ADDR_EXPR: |
| /* -- a unary operator & that is applied to an lvalue that |
| designates an object with thread or automatic storage |
| duration; */ |
| t = TREE_OPERAND (t, 0); |
| |
| if (TREE_CODE (t) == OFFSET_REF && PTRMEM_OK_P (t)) |
| /* A pointer-to-member constant. */ |
| return true; |
| |
| handle_addr_expr: |
| #if 0 |
| /* FIXME adjust when issue 1197 is fully resolved. For now don't do |
| any checking here, as we might dereference the pointer later. If |
| we remove this code, also remove check_automatic_or_tls. */ |
| i = check_automatic_or_tls (t); |
| if (i == ck_ok) |
| return true; |
| if (i == ck_bad) |
| { |
| if (flags & tf_error) |
| error ("address-of an object %qE with thread local or " |
| "automatic storage is not a constant expression", t); |
| return false; |
| } |
| #endif |
| return RECUR (t, any); |
| |
| case COMPONENT_REF: |
| case ARROW_EXPR: |
| case OFFSET_REF: |
| /* -- a class member access unless its postfix-expression is |
| of literal type or of pointer to literal type. */ |
| /* This test would be redundant, as it follows from the |
| postfix-expression being a potential constant expression. */ |
| if (type_unknown_p (t)) |
| return true; |
| if (is_overloaded_fn (t)) |
| /* In a template, a COMPONENT_REF of a function expresses ob.fn(), |
| which uses ob as an lvalue. */ |
| want_rval = false; |
| gcc_fallthrough (); |
| |
| case REALPART_EXPR: |
| case IMAGPART_EXPR: |
| case BIT_FIELD_REF: |
| return RECUR (TREE_OPERAND (t, 0), want_rval); |
| |
| case EXPR_PACK_EXPANSION: |
| return RECUR (PACK_EXPANSION_PATTERN (t), want_rval); |
| |
| case INDIRECT_REF: |
| { |
| tree x = TREE_OPERAND (t, 0); |
| STRIP_NOPS (x); |
| if (is_this_parameter (x) && !is_capture_proxy (x)) |
| { |
| if (!var_in_maybe_constexpr_fn (x)) |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "use of %<this%> in a " |
| "constant expression"); |
| return false; |
| } |
| return true; |
| } |
| return RECUR (x, rval); |
| } |
| |
| case STATEMENT_LIST: |
| for (tree stmt : tsi_range (t)) |
| if (!RECUR (stmt, any)) |
| return false; |
| return true; |
| |
| case MODIFY_EXPR: |
| if (cxx_dialect < cxx14) |
| goto fail; |
| if (!RECUR (TREE_OPERAND (t, 0), any)) |
| return false; |
| /* Just ignore clobbers. */ |
| if (TREE_CLOBBER_P (TREE_OPERAND (t, 1))) |
| return true; |
| if (!RECUR (TREE_OPERAND (t, 1), rval)) |
| return false; |
| return true; |
| |
| case MODOP_EXPR: |
| if (cxx_dialect < cxx14) |
| goto fail; |
| if (!RECUR (TREE_OPERAND (t, 0), rval)) |
| return false; |
| if (!RECUR (TREE_OPERAND (t, 2), rval)) |
| return false; |
| return true; |
| |
| case DO_STMT: |
| if (!RECUR (DO_COND (t), rval)) |
| return false; |
| if (!RECUR (DO_BODY (t), any)) |
| return false; |
| if (breaks (jump_target) || continues (jump_target)) |
| *jump_target = NULL_TREE; |
| return true; |
| |
| case FOR_STMT: |
| if (!RECUR (FOR_INIT_STMT (t), any)) |
| return false; |
| tmp = FOR_COND (t); |
| if (!RECUR (tmp, rval)) |
| return false; |
| if (tmp) |
| { |
| if (!processing_template_decl) |
| tmp = cxx_eval_outermost_constant_expr (tmp, true); |
| /* If we couldn't evaluate the condition, it might not ever be |
| true. */ |
| if (!integer_onep (tmp)) |
| { |
| /* Before returning true, check if the for body can contain |
| a return. */ |
| hash_set<tree> pset; |
| check_for_return_continue_data data = { &pset, NULL_TREE, |
| NULL_TREE }; |
| if (tree ret_expr |
| = cp_walk_tree (&FOR_BODY (t), check_for_return_continue, |
| &data, &pset)) |
| *jump_target = ret_expr; |
| return true; |
| } |
| } |
| if (!RECUR (FOR_EXPR (t), any)) |
| return false; |
| if (!RECUR (FOR_BODY (t), any)) |
| return false; |
| if (breaks (jump_target) || continues (jump_target)) |
| *jump_target = NULL_TREE; |
| return true; |
| |
| case RANGE_FOR_STMT: |
| if (!RECUR (RANGE_FOR_INIT_STMT (t), any)) |
| return false; |
| if (!RECUR (RANGE_FOR_EXPR (t), any)) |
| return false; |
| if (!RECUR (RANGE_FOR_BODY (t), any)) |
| return false; |
| if (breaks (jump_target) || continues (jump_target)) |
| *jump_target = NULL_TREE; |
| return true; |
| |
| case WHILE_STMT: |
| tmp = WHILE_COND (t); |
| if (!RECUR (tmp, rval)) |
| return false; |
| if (!processing_template_decl) |
| tmp = cxx_eval_outermost_constant_expr (tmp, true); |
| /* If we couldn't evaluate the condition, it might not ever be true. */ |
| if (!integer_onep (tmp)) |
| { |
| /* Before returning true, check if the while body can contain |
| a return. */ |
| hash_set<tree> pset; |
| check_for_return_continue_data data = { &pset, NULL_TREE, |
| NULL_TREE }; |
| if (tree ret_expr |
| = cp_walk_tree (&WHILE_BODY (t), check_for_return_continue, |
| &data, &pset)) |
| *jump_target = ret_expr; |
| return true; |
| } |
| if (!RECUR (WHILE_BODY (t), any)) |
| return false; |
| if (breaks (jump_target) || continues (jump_target)) |
| *jump_target = NULL_TREE; |
| return true; |
| |
| case SWITCH_STMT: |
| if (!RECUR (SWITCH_STMT_COND (t), rval)) |
| return false; |
| /* FIXME we don't check SWITCH_STMT_BODY currently, because even |
| unreachable labels would be checked and it is enough if there is |
| a single switch cond value for which it is a valid constant |
| expression. We need to check if there are any RETURN_EXPRs |
| or CONTINUE_STMTs inside of the body though, as in that case |
| we need to set *jump_target. */ |
| else |
| { |
| hash_set<tree> pset; |
| check_for_return_continue_data data = { &pset, NULL_TREE, |
| NULL_TREE }; |
| if (tree ret_expr |
| = cp_walk_tree (&SWITCH_STMT_BODY (t), check_for_return_continue, |
| &data, &pset)) |
| /* The switch might return. */ |
| *jump_target = ret_expr; |
| else if (data.continue_stmt) |
| /* The switch can't return, but might continue. */ |
| *jump_target = data.continue_stmt; |
| } |
| return true; |
| |
| case STMT_EXPR: |
| return RECUR (STMT_EXPR_STMT (t), rval); |
| |
| case LAMBDA_EXPR: |
| if (cxx_dialect >= cxx17) |
| /* In C++17 lambdas can be constexpr, don't give up yet. */ |
| return true; |
| else if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "lambda-expression is not a " |
| "constant expression before C++17"); |
| return false; |
| |
| case NEW_EXPR: |
| case VEC_NEW_EXPR: |
| case DELETE_EXPR: |
| case VEC_DELETE_EXPR: |
| if (cxx_dialect >= cxx20) |
| /* In C++20, new-expressions are potentially constant. */ |
| return true; |
| else if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "new-expression is not a " |
| "constant expression before C++20"); |
| return false; |
| |
| case DYNAMIC_CAST_EXPR: |
| case PSEUDO_DTOR_EXPR: |
| case THROW_EXPR: |
| case OMP_PARALLEL: |
| case OMP_TASK: |
| case OMP_FOR: |
| case OMP_SIMD: |
| case OMP_DISTRIBUTE: |
| case OMP_TASKLOOP: |
| case OMP_LOOP: |
| case OMP_TEAMS: |
| case OMP_TARGET_DATA: |
| case OMP_TARGET: |
| case OMP_SECTIONS: |
| case OMP_ORDERED: |
| case OMP_CRITICAL: |
| case OMP_SINGLE: |
| case OMP_SCAN: |
| case OMP_SCOPE: |
| case OMP_SECTION: |
| case OMP_MASTER: |
| case OMP_MASKED: |
| case OMP_TASKGROUP: |
| case OMP_TARGET_UPDATE: |
| case OMP_TARGET_ENTER_DATA: |
| case OMP_TARGET_EXIT_DATA: |
| case OMP_ATOMIC: |
| case OMP_ATOMIC_READ: |
| case OMP_ATOMIC_CAPTURE_OLD: |
| case OMP_ATOMIC_CAPTURE_NEW: |
| case OMP_DEPOBJ: |
| case OACC_PARALLEL: |
| case OACC_KERNELS: |
| case OACC_SERIAL: |
| case OACC_DATA: |
| case OACC_HOST_DATA: |
| case OACC_LOOP: |
| case OACC_CACHE: |
| case OACC_DECLARE: |
| case OACC_ENTER_DATA: |
| case OACC_EXIT_DATA: |
| case OACC_UPDATE: |
| /* GCC internal stuff. */ |
| case VA_ARG_EXPR: |
| case TRANSACTION_EXPR: |
| case AT_ENCODE_EXPR: |
| fail: |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "expression %qE is not a constant " |
| "expression", t); |
| return false; |
| |
| case ASM_EXPR: |
| if (flags & tf_error) |
| inline_asm_in_constexpr_error (loc, fundef_p); |
| return false; |
| |
| case OBJ_TYPE_REF: |
| if (cxx_dialect >= cxx20) |
| /* In C++20 virtual calls can be constexpr, don't give up yet. */ |
| return true; |
| else if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "virtual functions cannot be " |
| "%<constexpr%> before C++20"); |
| return false; |
| |
| case TYPEID_EXPR: |
| /* In C++20, a typeid expression whose operand is of polymorphic |
| class type can be constexpr. */ |
| { |
| tree e = TREE_OPERAND (t, 0); |
| if (cxx_dialect < cxx20 |
| && strict |
| && !TYPE_P (e) |
| && !type_dependent_expression_p (e) |
| && TYPE_POLYMORPHIC_P (TREE_TYPE (e))) |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "%<typeid%> is not a " |
| "constant expression because %qE is " |
| "of polymorphic type", e); |
| return false; |
| } |
| return true; |
| } |
| |
| case POINTER_DIFF_EXPR: |
| case MINUS_EXPR: |
| want_rval = true; |
| goto binary; |
| |
| case LT_EXPR: |
| case LE_EXPR: |
| case GT_EXPR: |
| case GE_EXPR: |
| case EQ_EXPR: |
| case NE_EXPR: |
| case SPACESHIP_EXPR: |
| want_rval = true; |
| goto binary; |
| |
| case PREINCREMENT_EXPR: |
| case POSTINCREMENT_EXPR: |
| case PREDECREMENT_EXPR: |
| case POSTDECREMENT_EXPR: |
| if (cxx_dialect < cxx14) |
| goto fail; |
| goto unary; |
| |
| case BIT_NOT_EXPR: |
| /* A destructor. */ |
| if (TYPE_P (TREE_OPERAND (t, 0))) |
| return true; |
| /* fall through. */ |
| |
| case CONJ_EXPR: |
| case SAVE_EXPR: |
| case FIX_TRUNC_EXPR: |
| case FLOAT_EXPR: |
| case NEGATE_EXPR: |
| case ABS_EXPR: |
| case ABSU_EXPR: |
| case TRUTH_NOT_EXPR: |
| case FIXED_CONVERT_EXPR: |
| case UNARY_PLUS_EXPR: |
| case UNARY_LEFT_FOLD_EXPR: |
| case UNARY_RIGHT_FOLD_EXPR: |
| unary: |
| return RECUR (TREE_OPERAND (t, 0), rval); |
| |
| case CAST_EXPR: |
| case CONST_CAST_EXPR: |
| case STATIC_CAST_EXPR: |
| case REINTERPRET_CAST_EXPR: |
| case IMPLICIT_CONV_EXPR: |
| if (!cast_valid_in_integral_constant_expression_p (TREE_TYPE (t))) |
| /* In C++98, a conversion to non-integral type can't be part of a |
| constant expression. */ |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, |
| "cast to non-integral type %qT in a constant " |
| "expression", TREE_TYPE (t)); |
| return false; |
| } |
| /* This might be a conversion from a class to a (potentially) literal |
| type. Let's consider it potentially constant since the conversion |
| might be a constexpr user-defined conversion. */ |
| else if (cxx_dialect >= cxx11 |
| && (dependent_type_p (TREE_TYPE (t)) |
| || !COMPLETE_TYPE_P (TREE_TYPE (t)) |
| || literal_type_p (TREE_TYPE (t))) |
| && TREE_OPERAND (t, 0)) |
| { |
| tree type = TREE_TYPE (TREE_OPERAND (t, 0)); |
| /* If this is a dependent type, it could end up being a class |
| with conversions. */ |
| if (type == NULL_TREE || WILDCARD_TYPE_P (type)) |
| return true; |
| /* Or a non-dependent class which has conversions. */ |
| else if (CLASS_TYPE_P (type) |
| && (TYPE_HAS_CONVERSION (type) || dependent_scope_p (type))) |
| return true; |
| } |
| |
| return (RECUR (TREE_OPERAND (t, 0), |
| !TYPE_REF_P (TREE_TYPE (t)))); |
| |
| case BIND_EXPR: |
| return RECUR (BIND_EXPR_BODY (t), want_rval); |
| |
| case NON_DEPENDENT_EXPR: |
| /* Treat NON_DEPENDENT_EXPR as non-constant: it's not handled by |
| constexpr evaluation or tsubst, so fold_non_dependent_expr can't |
| do anything useful with it. And we shouldn't see it in a context |
| where a constant expression is strictly required, hence the assert. */ |
| gcc_checking_assert (!(flags & tf_error)); |
| return false; |
| |
| case CLEANUP_POINT_EXPR: |
| case MUST_NOT_THROW_EXPR: |
| case TRY_CATCH_EXPR: |
| case TRY_BLOCK: |
| case EH_SPEC_BLOCK: |
| case EXPR_STMT: |
| case PAREN_EXPR: |
| /* For convenience. */ |
| case LOOP_EXPR: |
| case EXIT_EXPR: |
| return RECUR (TREE_OPERAND (t, 0), want_rval); |
| |
| case DECL_EXPR: |
| tmp = DECL_EXPR_DECL (t); |
| if (VAR_P (tmp) && !DECL_ARTIFICIAL (tmp) |
| && (processing_template_decl |
| ? !decl_maybe_constant_var_p (tmp) |
| : !decl_constant_var_p (tmp))) |
| { |
| if (CP_DECL_THREAD_LOCAL_P (tmp) && !DECL_REALLY_EXTERN (tmp)) |
| { |
| if (flags & tf_error) |
| constexpr_error (DECL_SOURCE_LOCATION (tmp), fundef_p, |
| "%qD defined %<thread_local%> in " |
| "%<constexpr%> context", tmp); |
| return false; |
| } |
| else if (TREE_STATIC (tmp)) |
| { |
| if (flags & tf_error) |
| constexpr_error (DECL_SOURCE_LOCATION (tmp), fundef_p, |
| "%qD defined %<static%> in %<constexpr%> " |
| "context", tmp); |
| return false; |
| } |
| else if (!check_for_uninitialized_const_var |
| (tmp, /*constexpr_context_p=*/true, flags)) |
| return false; |
| } |
| return RECUR (DECL_INITIAL (tmp), want_rval); |
| |
| case TRY_FINALLY_EXPR: |
| return (RECUR (TREE_OPERAND (t, 0), want_rval) |
| && RECUR (TREE_OPERAND (t, 1), any)); |
| |
| case SCOPE_REF: |
| return RECUR (TREE_OPERAND (t, 1), want_rval); |
| |
| case TARGET_EXPR: |
| if (!TARGET_EXPR_DIRECT_INIT_P (t) |
| && !literal_type_p (TREE_TYPE (t))) |
| { |
| if (flags & tf_error) |
| { |
| auto_diagnostic_group d; |
| if (constexpr_error (loc, fundef_p, |
| "temporary of non-literal type %qT in a " |
| "constant expression", TREE_TYPE (t))) |
| explain_non_literal_class (TREE_TYPE (t)); |
| } |
| return false; |
| } |
| /* FALLTHRU */ |
| case INIT_EXPR: |
| return RECUR (TREE_OPERAND (t, 1), rval); |
| |
| case CONSTRUCTOR: |
| { |
| vec<constructor_elt, va_gc> *v = CONSTRUCTOR_ELTS (t); |
| constructor_elt *ce; |
| for (i = 0; vec_safe_iterate (v, i, &ce); ++i) |
| if (!RECUR (ce->value, want_rval)) |
| return false; |
| return true; |
| } |
| |
| case TREE_LIST: |
| { |
| gcc_assert (TREE_PURPOSE (t) == NULL_TREE |
| || DECL_P (TREE_PURPOSE (t))); |
| if (!RECUR (TREE_VALUE (t), want_rval)) |
| return false; |
| if (TREE_CHAIN (t) == NULL_TREE) |
| return true; |
| return RECUR (TREE_CHAIN (t), want_rval); |
| } |
| |
| case TRUNC_DIV_EXPR: |
| case CEIL_DIV_EXPR: |
| case FLOOR_DIV_EXPR: |
| case ROUND_DIV_EXPR: |
| case TRUNC_MOD_EXPR: |
| case CEIL_MOD_EXPR: |
| case ROUND_MOD_EXPR: |
| { |
| tree denom = TREE_OPERAND (t, 1); |
| if (!RECUR (denom, rval)) |
| return false; |
| /* We can't call cxx_eval_outermost_constant_expr on an expression |
| that hasn't been through instantiate_non_dependent_expr yet. */ |
| if (!processing_template_decl) |
| denom = cxx_eval_outermost_constant_expr (denom, true); |
| if (integer_zerop (denom)) |
| { |
| if (flags & tf_error) |
| constexpr_error (input_location, fundef_p, |
| "division by zero is not a constant expression"); |
| return false; |
| } |
| else |
| { |
| want_rval = true; |
| return RECUR (TREE_OPERAND (t, 0), want_rval); |
| } |
| } |
| |
| case COMPOUND_EXPR: |
| { |
| /* check_return_expr sometimes wraps a TARGET_EXPR in a |
| COMPOUND_EXPR; don't get confused. */ |
| tree op0 = TREE_OPERAND (t, 0); |
| tree op1 = TREE_OPERAND (t, 1); |
| STRIP_NOPS (op1); |
| if (TREE_CODE (op0) == TARGET_EXPR && op1 == TARGET_EXPR_SLOT (op0)) |
| return RECUR (op0, want_rval); |
| else |
| goto binary; |
| } |
| |
| /* If the first operand is the non-short-circuit constant, look at |
| the second operand; otherwise we only care about the first one for |
| potentiality. */ |
| case TRUTH_AND_EXPR: |
| case TRUTH_ANDIF_EXPR: |
| tmp = boolean_true_node; |
| goto truth; |
| case TRUTH_OR_EXPR: |
| case TRUTH_ORIF_EXPR: |
| tmp = boolean_false_node; |
| truth: |
| { |
| tree op0 = TREE_OPERAND (t, 0); |
| tree op1 = TREE_OPERAND (t, 1); |
| if (!RECUR (op0, rval)) |
| return false; |
| if (!(flags & tf_error) && RECUR (op1, rval)) |
| /* When quiet, try to avoid expensive trial evaluation by first |
| checking potentiality of the second operand. */ |
| return true; |
| if (!processing_template_decl) |
| op0 = cxx_eval_outermost_constant_expr (op0, true); |
| if (tree_int_cst_equal (op0, tmp)) |
| return (flags & tf_error) ? RECUR (op1, rval) : false; |
| else |
| return true; |
| } |
| |
| case PLUS_EXPR: |
| case MULT_EXPR: |
| case POINTER_PLUS_EXPR: |
| case RDIV_EXPR: |
| case EXACT_DIV_EXPR: |
| case MIN_EXPR: |
| case MAX_EXPR: |
| case LSHIFT_EXPR: |
| case RSHIFT_EXPR: |
| case LROTATE_EXPR: |
| case RROTATE_EXPR: |
| case BIT_IOR_EXPR: |
| case BIT_XOR_EXPR: |
| case BIT_AND_EXPR: |
| case TRUTH_XOR_EXPR: |
| case UNORDERED_EXPR: |
| case ORDERED_EXPR: |
| case UNLT_EXPR: |
| case UNLE_EXPR: |
| case UNGT_EXPR: |
| case UNGE_EXPR: |
| case UNEQ_EXPR: |
| case LTGT_EXPR: |
| case RANGE_EXPR: |
| case COMPLEX_EXPR: |
| want_rval = true; |
| /* Fall through. */ |
| case ARRAY_REF: |
| case ARRAY_RANGE_REF: |
| case MEMBER_REF: |
| case DOTSTAR_EXPR: |
| case MEM_REF: |
| case BINARY_LEFT_FOLD_EXPR: |
| case BINARY_RIGHT_FOLD_EXPR: |
| binary: |
| for (i = 0; i < 2; ++i) |
| if (!RECUR (TREE_OPERAND (t, i), want_rval)) |
| return false; |
| return true; |
| |
| case VEC_PERM_EXPR: |
| for (i = 0; i < 3; ++i) |
| if (!RECUR (TREE_OPERAND (t, i), true)) |
| return false; |
| return true; |
| |
| case COND_EXPR: |
| if (COND_EXPR_IS_VEC_DELETE (t) && cxx_dialect < cxx20) |
| { |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "%<delete[]%> is not a " |
| "constant expression"); |
| return false; |
| } |
| /* Fall through. */ |
| case IF_STMT: |
| case VEC_COND_EXPR: |
| /* If the condition is a known constant, we know which of the legs we |
| care about; otherwise we only require that the condition and |
| either of the legs be potentially constant. */ |
| tmp = TREE_OPERAND (t, 0); |
| if (!RECUR (tmp, rval)) |
| return false; |
| if (!processing_template_decl) |
| tmp = cxx_eval_outermost_constant_expr (tmp, true); |
| /* potential_constant_expression* isn't told if it is called for |
| manifestly_const_eval or not, so for consteval if always |
| process both branches as if the condition is not a known |
| constant. */ |
| if (TREE_CODE (t) != IF_STMT || !IF_STMT_CONSTEVAL_P (t)) |
| { |
| if (integer_zerop (tmp)) |
| return RECUR (TREE_OPERAND (t, 2), want_rval); |
| else if (TREE_CODE (tmp) == INTEGER_CST) |
| return RECUR (TREE_OPERAND (t, 1), want_rval); |
| } |
| tmp = *jump_target; |
| for (i = 1; i < 3; ++i) |
| { |
| tree this_jump_target = tmp; |
| if (potential_constant_expression_1 (TREE_OPERAND (t, i), |
| want_rval, strict, now, fundef_p, |
| tf_none, &this_jump_target)) |
| { |
| if (returns (&this_jump_target)) |
| *jump_target = this_jump_target; |
| else if (!returns (jump_target)) |
| { |
| if (breaks (&this_jump_target) |
| || continues (&this_jump_target)) |
| *jump_target = this_jump_target; |
| if (i == 1) |
| { |
| /* If the then branch is potentially constant, but |
| does not return, check if the else branch |
| couldn't return, break or continue. */ |
| hash_set<tree> pset; |
| check_for_return_continue_data data = { &pset, NULL_TREE, |
| NULL_TREE }; |
| if (tree ret_expr |
| = cp_walk_tree (&TREE_OPERAND (t, 2), |
| check_for_return_continue, &data, |
| &pset)) |
| *jump_target = ret_expr; |
| else if (*jump_target == NULL_TREE) |
| { |
| if (data.continue_stmt) |
| *jump_target = data.continue_stmt; |
| else if (data.break_stmt) |
| *jump_target = data.break_stmt; |
| } |
| } |
| } |
| return true; |
| } |
| } |
| if (flags & tf_error) |
| { |
| if (TREE_CODE (t) == IF_STMT) |
| constexpr_error (loc, fundef_p, "neither branch of %<if%> is a " |
| "constant expression"); |
| else |
| constexpr_error (loc, fundef_p, "expression %qE is not a " |
| "constant expression", t); |
| } |
| return false; |
| |
| case VEC_INIT_EXPR: |
| if (VEC_INIT_EXPR_IS_CONSTEXPR (t)) |
| return true; |
| if (flags & tf_error) |
| { |
| if (constexpr_error (loc, fundef_p, "non-constant array " |
| "initialization")) |
| diagnose_non_constexpr_vec_init (t); |
| } |
| return false; |
| |
| case TYPE_DECL: |
| case TAG_DEFN: |
| /* We can see these in statement-expressions. */ |
| return true; |
| |
| case CLEANUP_STMT: |
| if (!RECUR (CLEANUP_BODY (t), any)) |
| return false; |
| if (!CLEANUP_EH_ONLY (t) && !RECUR (CLEANUP_EXPR (t), any)) |
| return false; |
| return true; |
| |
| case EMPTY_CLASS_EXPR: |
| return true; |
| |
| case GOTO_EXPR: |
| { |
| tree *target = &TREE_OPERAND (t, 0); |
| /* Gotos representing break, continue and cdtor return are OK. */ |
| if (breaks (target) || continues (target) || returns (target)) |
| { |
| *jump_target = *target; |
| return true; |
| } |
| if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "%<goto%> is not a constant " |
| "expression"); |
| return false; |
| } |
| |
| case ASSERTION_STMT: |
| case PRECONDITION_STMT: |
| case POSTCONDITION_STMT: |
| if (!checked_contract_p (get_contract_semantic (t))) |
| return true; |
| return RECUR (CONTRACT_CONDITION (t), rval); |
| |
| case LABEL_EXPR: |
| t = LABEL_EXPR_LABEL (t); |
| if (DECL_ARTIFICIAL (t) || cxx_dialect >= cxx23) |
| return true; |
| else if (flags & tf_error) |
| constexpr_error (loc, fundef_p, "label definition in %<constexpr%> " |
| "function only available with %<-std=c++2b%> or " |
| "%<-std=gnu++2b%>"); |
| return false; |
| |
| case ANNOTATE_EXPR: |
| return RECUR (TREE_OPERAND (t, 0), rval); |
| |
| case BIT_CAST_EXPR: |
| return RECUR (TREE_OPERAND (t, 0), rval); |
| |
| /* Coroutine await, yield and return expressions are not. */ |
| case CO_AWAIT_EXPR: |
| case CO_YIELD_EXPR: |
| case CO_RETURN_EXPR: |
| return false; |
| |
| case NONTYPE_ARGUMENT_PACK: |
| { |
| tree args = ARGUMENT_PACK_ARGS (t); |
| int len = TREE_VEC_LENGTH (args); |
| for (int i = 0; i < len; ++i) |
| if (!RECUR (TREE_VEC_ELT (args, i), any)) |
| return false; |
| return true; |
| } |
| |
| default: |
| if (objc_non_constant_expr_p (t)) |
| return false; |
| |
| sorry ("unexpected AST of kind %s", get_tree_code_name (TREE_CODE (t))); |
| gcc_unreachable (); |
| return false; |
| } |
| #undef RECUR |
| } |
| |
| bool |
| potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, |
| bool fundef_p, tsubst_flags_t flags) |
| { |
| if (flags & tf_error) |
| { |
| /* Check potentiality quietly first, as that could be performed more |
| efficiently in some cases (currently only for TRUTH_*_EXPR). If |
| that fails, replay the check noisily to give errors. */ |
| flags &= ~tf_error; |
| if (potential_constant_expression_1 (t, want_rval, strict, now, fundef_p, |
| flags)) |
| return true; |
| flags |= tf_error; |
| } |
| |
| tree target = NULL_TREE; |
| return potential_constant_expression_1 (t, want_rval, strict, now, fundef_p, |
| flags, &target); |
| } |
| |
| /* The main entry point to the above. */ |
| |
| bool |
| potential_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/false, /*strict*/true, |
| /*now*/false, /*fundef_p*/false, |
| tf_none); |
| } |
| |
| /* As above, but require a constant rvalue. */ |
| |
| bool |
| potential_rvalue_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/true, /*strict*/true, |
| /*now*/false, /*fundef_p*/false, |
| tf_none); |
| } |
| |
| /* Like above, but complain about non-constant expressions. */ |
| |
| bool |
| require_potential_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/false, /*strict*/true, |
| /*now*/false, /*fundef_p*/false, |
| tf_warning_or_error); |
| } |
| |
| /* Cross product of the above. */ |
| |
| bool |
| require_potential_rvalue_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/true, /*strict*/true, |
| /*now*/false, /*fundef_p*/false, |
| tf_warning_or_error); |
| } |
| |
| /* Like require_potential_rvalue_constant_expression, but fundef_p is true. */ |
| |
| bool |
| require_potential_rvalue_constant_expression_fncheck (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/true, /*strict*/true, |
| /*now*/false, /*fundef_p*/true, |
| tf_warning_or_error); |
| } |
| |
| /* Like above, but don't consider PARM_DECL a potential_constant_expression. */ |
| |
| bool |
| require_rvalue_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/true, /*strict*/true, |
| /*now*/true, /*fundef_p*/false, |
| tf_warning_or_error); |
| } |
| |
| /* Like potential_constant_expression, but don't consider possible constexpr |
| substitution of the current function. That is, PARM_DECL qualifies under |
| potential_constant_expression, but not here. |
| |
| This is basically what you can check when any actual constant values might |
| be value-dependent. */ |
| |
| bool |
| is_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/false, /*strict*/true, |
| /*now*/true, /*fundef_p*/false, |
| tf_none); |
| } |
| |
| /* As above, but expect an rvalue. */ |
| |
| bool |
| is_rvalue_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/true, /*strict*/true, |
| /*now*/true, /*fundef_p*/false, |
| tf_none); |
| } |
| |
| /* Like above, but complain about non-constant expressions. */ |
| |
| bool |
| require_constant_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/false, /*strict*/true, |
| /*now*/true, /*fundef_p*/false, |
| tf_warning_or_error); |
| } |
| |
| /* Like is_constant_expression, but allow const variables that are not allowed |
| under constexpr rules. */ |
| |
| bool |
| is_static_init_expression (tree t) |
| { |
| return potential_constant_expression_1 (t, /*want_rval*/false, |
| /*strict*/false, /*now*/true, |
| /*fundef_p*/false, tf_none); |
| } |
| |
| /* Returns true if T is a potential constant expression that is not |
| instantiation-dependent, and therefore a candidate for constant folding even |
| in a template. */ |
| |
| bool |
| is_nondependent_constant_expression (tree t) |
| { |
| return (!type_unknown_p (t) |
| && is_constant_expression (t) |
| && !instantiation_dependent_expression_p (t)); |
| } |
| |
| /* Returns true if T is a potential static initializer expression that is not |
| instantiation-dependent. */ |
| |
| bool |
| is_nondependent_static_init_expression (tree t) |
| { |
| return (!type_unknown_p (t) |
| && is_static_init_expression (t) |
| && !instantiation_dependent_expression_p (t)); |
| } |
| |
| /* True iff FN is an implicitly constexpr function. */ |
| |
| bool |
| decl_implicit_constexpr_p (tree fn) |
| { |
| if (!(flag_implicit_constexpr |
| && TREE_CODE (fn) == FUNCTION_DECL |
| && DECL_DECLARED_CONSTEXPR_P (fn))) |
| return false; |
| |
| if (DECL_CLONED_FUNCTION_P (fn)) |
| fn = DECL_CLONED_FUNCTION (fn); |
| |
| return (DECL_LANG_SPECIFIC (fn) |
| && DECL_LANG_SPECIFIC (fn)->u.fn.implicit_constexpr); |
| } |
| |
| /* Finalize constexpr processing after parsing. */ |
| |
| void |
| fini_constexpr (void) |
| { |
| /* The contexpr call and fundef copies tables are no longer needed. */ |
| constexpr_call_table = NULL; |
| fundef_copies_table = NULL; |
| } |
| |
| #include "gt-cp-constexpr.h" |