| /* Alias analysis for trees. |
| Copyright (C) 2004-2017 Free Software Foundation, Inc. |
| Contributed by Diego Novillo <dnovillo@redhat.com> |
| |
| 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 "backend.h" |
| #include "target.h" |
| #include "rtl.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "timevar.h" /* for TV_ALIAS_STMT_WALK */ |
| #include "ssa.h" |
| #include "cgraph.h" |
| #include "tree-pretty-print.h" |
| #include "alias.h" |
| #include "fold-const.h" |
| #include "langhooks.h" |
| #include "dumpfile.h" |
| #include "tree-eh.h" |
| #include "tree-dfa.h" |
| #include "ipa-reference.h" |
| #include "varasm.h" |
| |
| /* Broad overview of how alias analysis on gimple works: |
| |
| Statements clobbering or using memory are linked through the |
| virtual operand factored use-def chain. The virtual operand |
| is unique per function, its symbol is accessible via gimple_vop (cfun). |
| Virtual operands are used for efficiently walking memory statements |
| in the gimple IL and are useful for things like value-numbering as |
| a generation count for memory references. |
| |
| SSA_NAME pointers may have associated points-to information |
| accessible via the SSA_NAME_PTR_INFO macro. Flow-insensitive |
| points-to information is (re-)computed by the TODO_rebuild_alias |
| pass manager todo. Points-to information is also used for more |
| precise tracking of call-clobbered and call-used variables and |
| related disambiguations. |
| |
| This file contains functions for disambiguating memory references, |
| the so called alias-oracle and tools for walking of the gimple IL. |
| |
| The main alias-oracle entry-points are |
| |
| bool stmt_may_clobber_ref_p (gimple *, tree) |
| |
| This function queries if a statement may invalidate (parts of) |
| the memory designated by the reference tree argument. |
| |
| bool ref_maybe_used_by_stmt_p (gimple *, tree) |
| |
| This function queries if a statement may need (parts of) the |
| memory designated by the reference tree argument. |
| |
| There are variants of these functions that only handle the call |
| part of a statement, call_may_clobber_ref_p and ref_maybe_used_by_call_p. |
| Note that these do not disambiguate against a possible call lhs. |
| |
| bool refs_may_alias_p (tree, tree) |
| |
| This function tries to disambiguate two reference trees. |
| |
| bool ptr_deref_may_alias_global_p (tree) |
| |
| This function queries if dereferencing a pointer variable may |
| alias global memory. |
| |
| More low-level disambiguators are available and documented in |
| this file. Low-level disambiguators dealing with points-to |
| information are in tree-ssa-structalias.c. */ |
| |
| |
| /* Query statistics for the different low-level disambiguators. |
| A high-level query may trigger multiple of them. */ |
| |
| static struct { |
| unsigned HOST_WIDE_INT refs_may_alias_p_may_alias; |
| unsigned HOST_WIDE_INT refs_may_alias_p_no_alias; |
| unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_may_alias; |
| unsigned HOST_WIDE_INT ref_maybe_used_by_call_p_no_alias; |
| unsigned HOST_WIDE_INT call_may_clobber_ref_p_may_alias; |
| unsigned HOST_WIDE_INT call_may_clobber_ref_p_no_alias; |
| } alias_stats; |
| |
| void |
| dump_alias_stats (FILE *s) |
| { |
| fprintf (s, "\nAlias oracle query stats:\n"); |
| fprintf (s, " refs_may_alias_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.refs_may_alias_p_no_alias, |
| alias_stats.refs_may_alias_p_no_alias |
| + alias_stats.refs_may_alias_p_may_alias); |
| fprintf (s, " ref_maybe_used_by_call_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.ref_maybe_used_by_call_p_no_alias, |
| alias_stats.refs_may_alias_p_no_alias |
| + alias_stats.ref_maybe_used_by_call_p_may_alias); |
| fprintf (s, " call_may_clobber_ref_p: " |
| HOST_WIDE_INT_PRINT_DEC" disambiguations, " |
| HOST_WIDE_INT_PRINT_DEC" queries\n", |
| alias_stats.call_may_clobber_ref_p_no_alias, |
| alias_stats.call_may_clobber_ref_p_no_alias |
| + alias_stats.call_may_clobber_ref_p_may_alias); |
| dump_alias_stats_in_alias_c (s); |
| } |
| |
| |
| /* Return true, if dereferencing PTR may alias with a global variable. */ |
| |
| bool |
| ptr_deref_may_alias_global_p (tree ptr) |
| { |
| struct ptr_info_def *pi; |
| |
| /* If we end up with a pointer constant here that may point |
| to global memory. */ |
| if (TREE_CODE (ptr) != SSA_NAME) |
| return true; |
| |
| pi = SSA_NAME_PTR_INFO (ptr); |
| |
| /* If we do not have points-to information for this variable, |
| we have to punt. */ |
| if (!pi) |
| return true; |
| |
| /* ??? This does not use TBAA to prune globals ptr may not access. */ |
| return pt_solution_includes_global (&pi->pt); |
| } |
| |
| /* Return true if dereferencing PTR may alias DECL. |
| The caller is responsible for applying TBAA to see if PTR |
| may access DECL at all. */ |
| |
| static bool |
| ptr_deref_may_alias_decl_p (tree ptr, tree decl) |
| { |
| struct ptr_info_def *pi; |
| |
| /* Conversions are irrelevant for points-to information and |
| data-dependence analysis can feed us those. */ |
| STRIP_NOPS (ptr); |
| |
| /* Anything we do not explicilty handle aliases. */ |
| if ((TREE_CODE (ptr) != SSA_NAME |
| && TREE_CODE (ptr) != ADDR_EXPR |
| && TREE_CODE (ptr) != POINTER_PLUS_EXPR) |
| || !POINTER_TYPE_P (TREE_TYPE (ptr)) |
| || (!VAR_P (decl) |
| && TREE_CODE (decl) != PARM_DECL |
| && TREE_CODE (decl) != RESULT_DECL)) |
| return true; |
| |
| /* Disregard pointer offsetting. */ |
| if (TREE_CODE (ptr) == POINTER_PLUS_EXPR) |
| { |
| do |
| { |
| ptr = TREE_OPERAND (ptr, 0); |
| } |
| while (TREE_CODE (ptr) == POINTER_PLUS_EXPR); |
| return ptr_deref_may_alias_decl_p (ptr, decl); |
| } |
| |
| /* ADDR_EXPR pointers either just offset another pointer or directly |
| specify the pointed-to set. */ |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| tree base = get_base_address (TREE_OPERAND (ptr, 0)); |
| if (base |
| && (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF)) |
| ptr = TREE_OPERAND (base, 0); |
| else if (base |
| && DECL_P (base)) |
| return compare_base_decls (base, decl) != 0; |
| else if (base |
| && CONSTANT_CLASS_P (base)) |
| return false; |
| else |
| return true; |
| } |
| |
| /* Non-aliased variables can not be pointed to. */ |
| if (!may_be_aliased (decl)) |
| return false; |
| |
| /* If we do not have useful points-to information for this pointer |
| we cannot disambiguate anything else. */ |
| pi = SSA_NAME_PTR_INFO (ptr); |
| if (!pi) |
| return true; |
| |
| return pt_solution_includes (&pi->pt, decl); |
| } |
| |
| /* Return true if dereferenced PTR1 and PTR2 may alias. |
| The caller is responsible for applying TBAA to see if accesses |
| through PTR1 and PTR2 may conflict at all. */ |
| |
| bool |
| ptr_derefs_may_alias_p (tree ptr1, tree ptr2) |
| { |
| struct ptr_info_def *pi1, *pi2; |
| |
| /* Conversions are irrelevant for points-to information and |
| data-dependence analysis can feed us those. */ |
| STRIP_NOPS (ptr1); |
| STRIP_NOPS (ptr2); |
| |
| /* Disregard pointer offsetting. */ |
| if (TREE_CODE (ptr1) == POINTER_PLUS_EXPR) |
| { |
| do |
| { |
| ptr1 = TREE_OPERAND (ptr1, 0); |
| } |
| while (TREE_CODE (ptr1) == POINTER_PLUS_EXPR); |
| return ptr_derefs_may_alias_p (ptr1, ptr2); |
| } |
| if (TREE_CODE (ptr2) == POINTER_PLUS_EXPR) |
| { |
| do |
| { |
| ptr2 = TREE_OPERAND (ptr2, 0); |
| } |
| while (TREE_CODE (ptr2) == POINTER_PLUS_EXPR); |
| return ptr_derefs_may_alias_p (ptr1, ptr2); |
| } |
| |
| /* ADDR_EXPR pointers either just offset another pointer or directly |
| specify the pointed-to set. */ |
| if (TREE_CODE (ptr1) == ADDR_EXPR) |
| { |
| tree base = get_base_address (TREE_OPERAND (ptr1, 0)); |
| if (base |
| && (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF)) |
| return ptr_derefs_may_alias_p (TREE_OPERAND (base, 0), ptr2); |
| else if (base |
| && DECL_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr2, base); |
| else |
| return true; |
| } |
| if (TREE_CODE (ptr2) == ADDR_EXPR) |
| { |
| tree base = get_base_address (TREE_OPERAND (ptr2, 0)); |
| if (base |
| && (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF)) |
| return ptr_derefs_may_alias_p (ptr1, TREE_OPERAND (base, 0)); |
| else if (base |
| && DECL_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr1, base); |
| else |
| return true; |
| } |
| |
| /* From here we require SSA name pointers. Anything else aliases. */ |
| if (TREE_CODE (ptr1) != SSA_NAME |
| || TREE_CODE (ptr2) != SSA_NAME |
| || !POINTER_TYPE_P (TREE_TYPE (ptr1)) |
| || !POINTER_TYPE_P (TREE_TYPE (ptr2))) |
| return true; |
| |
| /* We may end up with two empty points-to solutions for two same pointers. |
| In this case we still want to say both pointers alias, so shortcut |
| that here. */ |
| if (ptr1 == ptr2) |
| return true; |
| |
| /* If we do not have useful points-to information for either pointer |
| we cannot disambiguate anything else. */ |
| pi1 = SSA_NAME_PTR_INFO (ptr1); |
| pi2 = SSA_NAME_PTR_INFO (ptr2); |
| if (!pi1 || !pi2) |
| return true; |
| |
| /* ??? This does not use TBAA to prune decls from the intersection |
| that not both pointers may access. */ |
| return pt_solutions_intersect (&pi1->pt, &pi2->pt); |
| } |
| |
| /* Return true if dereferencing PTR may alias *REF. |
| The caller is responsible for applying TBAA to see if PTR |
| may access *REF at all. */ |
| |
| static bool |
| ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref) |
| { |
| tree base = ao_ref_base (ref); |
| |
| if (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| return ptr_derefs_may_alias_p (ptr, TREE_OPERAND (base, 0)); |
| else if (DECL_P (base)) |
| return ptr_deref_may_alias_decl_p (ptr, base); |
| |
| return true; |
| } |
| |
| /* Returns true if PTR1 and PTR2 compare unequal because of points-to. */ |
| |
| bool |
| ptrs_compare_unequal (tree ptr1, tree ptr2) |
| { |
| /* First resolve the pointers down to a SSA name pointer base or |
| a VAR_DECL, PARM_DECL or RESULT_DECL. This explicitely does |
| not yet try to handle LABEL_DECLs, FUNCTION_DECLs, CONST_DECLs |
| or STRING_CSTs which needs points-to adjustments to track them |
| in the points-to sets. */ |
| tree obj1 = NULL_TREE; |
| tree obj2 = NULL_TREE; |
| if (TREE_CODE (ptr1) == ADDR_EXPR) |
| { |
| tree tem = get_base_address (TREE_OPERAND (ptr1, 0)); |
| if (! tem) |
| return false; |
| if (VAR_P (tem) |
| || TREE_CODE (tem) == PARM_DECL |
| || TREE_CODE (tem) == RESULT_DECL) |
| obj1 = tem; |
| else if (TREE_CODE (tem) == MEM_REF) |
| ptr1 = TREE_OPERAND (tem, 0); |
| } |
| if (TREE_CODE (ptr2) == ADDR_EXPR) |
| { |
| tree tem = get_base_address (TREE_OPERAND (ptr2, 0)); |
| if (! tem) |
| return false; |
| if (VAR_P (tem) |
| || TREE_CODE (tem) == PARM_DECL |
| || TREE_CODE (tem) == RESULT_DECL) |
| obj2 = tem; |
| else if (TREE_CODE (tem) == MEM_REF) |
| ptr2 = TREE_OPERAND (tem, 0); |
| } |
| |
| /* Canonicalize ptr vs. object. */ |
| if (TREE_CODE (ptr1) == SSA_NAME && obj2) |
| { |
| std::swap (ptr1, ptr2); |
| std::swap (obj1, obj2); |
| } |
| |
| if (obj1 && obj2) |
| /* Other code handles this correctly, no need to duplicate it here. */; |
| else if (obj1 && TREE_CODE (ptr2) == SSA_NAME) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr2); |
| /* We may not use restrict to optimize pointer comparisons. |
| See PR71062. So we have to assume that restrict-pointed-to |
| may be in fact obj1. */ |
| if (!pi |
| || pi->pt.vars_contains_restrict |
| || pi->pt.vars_contains_interposable) |
| return false; |
| if (VAR_P (obj1) |
| && (TREE_STATIC (obj1) || DECL_EXTERNAL (obj1))) |
| { |
| varpool_node *node = varpool_node::get (obj1); |
| /* If obj1 may bind to NULL give up (see below). */ |
| if (! node |
| || ! node->nonzero_address () |
| || ! decl_binds_to_current_def_p (obj1)) |
| return false; |
| } |
| return !pt_solution_includes (&pi->pt, obj1); |
| } |
| |
| /* ??? We'd like to handle ptr1 != NULL and ptr1 != ptr2 |
| but those require pt.null to be conservatively correct. */ |
| |
| return false; |
| } |
| |
| /* Returns whether reference REF to BASE may refer to global memory. */ |
| |
| static bool |
| ref_may_alias_global_p_1 (tree base) |
| { |
| if (DECL_P (base)) |
| return is_global_var (base); |
| else if (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0)); |
| return true; |
| } |
| |
| bool |
| ref_may_alias_global_p (ao_ref *ref) |
| { |
| tree base = ao_ref_base (ref); |
| return ref_may_alias_global_p_1 (base); |
| } |
| |
| bool |
| ref_may_alias_global_p (tree ref) |
| { |
| tree base = get_base_address (ref); |
| return ref_may_alias_global_p_1 (base); |
| } |
| |
| /* Return true whether STMT may clobber global memory. */ |
| |
| bool |
| stmt_may_clobber_global_p (gimple *stmt) |
| { |
| tree lhs; |
| |
| if (!gimple_vdef (stmt)) |
| return false; |
| |
| /* ??? We can ask the oracle whether an artificial pointer |
| dereference with a pointer with points-to information covering |
| all global memory (what about non-address taken memory?) maybe |
| clobbered by this call. As there is at the moment no convenient |
| way of doing that without generating garbage do some manual |
| checking instead. |
| ??? We could make a NULL ao_ref argument to the various |
| predicates special, meaning any global memory. */ |
| |
| switch (gimple_code (stmt)) |
| { |
| case GIMPLE_ASSIGN: |
| lhs = gimple_assign_lhs (stmt); |
| return (TREE_CODE (lhs) != SSA_NAME |
| && ref_may_alias_global_p (lhs)); |
| case GIMPLE_CALL: |
| return true; |
| default: |
| return true; |
| } |
| } |
| |
| |
| /* Dump alias information on FILE. */ |
| |
| void |
| dump_alias_info (FILE *file) |
| { |
| unsigned i; |
| tree ptr; |
| const char *funcname |
| = lang_hooks.decl_printable_name (current_function_decl, 2); |
| tree var; |
| |
| fprintf (file, "\n\nAlias information for %s\n\n", funcname); |
| |
| fprintf (file, "Aliased symbols\n\n"); |
| |
| FOR_EACH_LOCAL_DECL (cfun, i, var) |
| { |
| if (may_be_aliased (var)) |
| dump_variable (file, var); |
| } |
| |
| fprintf (file, "\nCall clobber information\n"); |
| |
| fprintf (file, "\nESCAPED"); |
| dump_points_to_solution (file, &cfun->gimple_df->escaped); |
| |
| fprintf (file, "\n\nFlow-insensitive points-to information\n\n"); |
| |
| FOR_EACH_SSA_NAME (i, ptr, cfun) |
| { |
| struct ptr_info_def *pi; |
| |
| if (!POINTER_TYPE_P (TREE_TYPE (ptr)) |
| || SSA_NAME_IN_FREE_LIST (ptr)) |
| continue; |
| |
| pi = SSA_NAME_PTR_INFO (ptr); |
| if (pi) |
| dump_points_to_info_for (file, ptr); |
| } |
| |
| fprintf (file, "\n"); |
| } |
| |
| |
| /* Dump alias information on stderr. */ |
| |
| DEBUG_FUNCTION void |
| debug_alias_info (void) |
| { |
| dump_alias_info (stderr); |
| } |
| |
| |
| /* Dump the points-to set *PT into FILE. */ |
| |
| void |
| dump_points_to_solution (FILE *file, struct pt_solution *pt) |
| { |
| if (pt->anything) |
| fprintf (file, ", points-to anything"); |
| |
| if (pt->nonlocal) |
| fprintf (file, ", points-to non-local"); |
| |
| if (pt->escaped) |
| fprintf (file, ", points-to escaped"); |
| |
| if (pt->ipa_escaped) |
| fprintf (file, ", points-to unit escaped"); |
| |
| if (pt->null) |
| fprintf (file, ", points-to NULL"); |
| |
| if (pt->vars) |
| { |
| fprintf (file, ", points-to vars: "); |
| dump_decl_set (file, pt->vars); |
| if (pt->vars_contains_nonlocal |
| || pt->vars_contains_escaped |
| || pt->vars_contains_escaped_heap |
| || pt->vars_contains_restrict) |
| { |
| const char *comma = ""; |
| fprintf (file, " ("); |
| if (pt->vars_contains_nonlocal) |
| { |
| fprintf (file, "nonlocal"); |
| comma = ", "; |
| } |
| if (pt->vars_contains_escaped) |
| { |
| fprintf (file, "%sescaped", comma); |
| comma = ", "; |
| } |
| if (pt->vars_contains_escaped_heap) |
| { |
| fprintf (file, "%sescaped heap", comma); |
| comma = ", "; |
| } |
| if (pt->vars_contains_restrict) |
| { |
| fprintf (file, "%srestrict", comma); |
| comma = ", "; |
| } |
| if (pt->vars_contains_interposable) |
| fprintf (file, "%sinterposable", comma); |
| fprintf (file, ")"); |
| } |
| } |
| } |
| |
| |
| /* Unified dump function for pt_solution. */ |
| |
| DEBUG_FUNCTION void |
| debug (pt_solution &ref) |
| { |
| dump_points_to_solution (stderr, &ref); |
| } |
| |
| DEBUG_FUNCTION void |
| debug (pt_solution *ptr) |
| { |
| if (ptr) |
| debug (*ptr); |
| else |
| fprintf (stderr, "<nil>\n"); |
| } |
| |
| |
| /* Dump points-to information for SSA_NAME PTR into FILE. */ |
| |
| void |
| dump_points_to_info_for (FILE *file, tree ptr) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr); |
| |
| print_generic_expr (file, ptr, dump_flags); |
| |
| if (pi) |
| dump_points_to_solution (file, &pi->pt); |
| else |
| fprintf (file, ", points-to anything"); |
| |
| fprintf (file, "\n"); |
| } |
| |
| |
| /* Dump points-to information for VAR into stderr. */ |
| |
| DEBUG_FUNCTION void |
| debug_points_to_info_for (tree var) |
| { |
| dump_points_to_info_for (stderr, var); |
| } |
| |
| |
| /* Initializes the alias-oracle reference representation *R from REF. */ |
| |
| void |
| ao_ref_init (ao_ref *r, tree ref) |
| { |
| r->ref = ref; |
| r->base = NULL_TREE; |
| r->offset = 0; |
| r->size = -1; |
| r->max_size = -1; |
| r->ref_alias_set = -1; |
| r->base_alias_set = -1; |
| r->volatile_p = ref ? TREE_THIS_VOLATILE (ref) : false; |
| } |
| |
| /* Returns the base object of the memory reference *REF. */ |
| |
| tree |
| ao_ref_base (ao_ref *ref) |
| { |
| bool reverse; |
| |
| if (ref->base) |
| return ref->base; |
| ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size, |
| &ref->max_size, &reverse); |
| return ref->base; |
| } |
| |
| /* Returns the base object alias set of the memory reference *REF. */ |
| |
| alias_set_type |
| ao_ref_base_alias_set (ao_ref *ref) |
| { |
| tree base_ref; |
| if (ref->base_alias_set != -1) |
| return ref->base_alias_set; |
| if (!ref->ref) |
| return 0; |
| base_ref = ref->ref; |
| while (handled_component_p (base_ref)) |
| base_ref = TREE_OPERAND (base_ref, 0); |
| ref->base_alias_set = get_alias_set (base_ref); |
| return ref->base_alias_set; |
| } |
| |
| /* Returns the reference alias set of the memory reference *REF. */ |
| |
| alias_set_type |
| ao_ref_alias_set (ao_ref *ref) |
| { |
| if (ref->ref_alias_set != -1) |
| return ref->ref_alias_set; |
| ref->ref_alias_set = get_alias_set (ref->ref); |
| return ref->ref_alias_set; |
| } |
| |
| /* Init an alias-oracle reference representation from a gimple pointer |
| PTR and a gimple size SIZE in bytes. If SIZE is NULL_TREE then the |
| size is assumed to be unknown. The access is assumed to be only |
| to or after of the pointer target, not before it. */ |
| |
| void |
| ao_ref_init_from_ptr_and_size (ao_ref *ref, tree ptr, tree size) |
| { |
| HOST_WIDE_INT t, size_hwi, extra_offset = 0; |
| ref->ref = NULL_TREE; |
| if (TREE_CODE (ptr) == SSA_NAME) |
| { |
| gimple *stmt = SSA_NAME_DEF_STMT (ptr); |
| if (gimple_assign_single_p (stmt) |
| && gimple_assign_rhs_code (stmt) == ADDR_EXPR) |
| ptr = gimple_assign_rhs1 (stmt); |
| else if (is_gimple_assign (stmt) |
| && gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR |
| && TREE_CODE (gimple_assign_rhs2 (stmt)) == INTEGER_CST) |
| { |
| ptr = gimple_assign_rhs1 (stmt); |
| extra_offset = BITS_PER_UNIT |
| * int_cst_value (gimple_assign_rhs2 (stmt)); |
| } |
| } |
| |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| ref->base = get_addr_base_and_unit_offset (TREE_OPERAND (ptr, 0), &t); |
| if (ref->base) |
| ref->offset = BITS_PER_UNIT * t; |
| else |
| { |
| size = NULL_TREE; |
| ref->offset = 0; |
| ref->base = get_base_address (TREE_OPERAND (ptr, 0)); |
| } |
| } |
| else |
| { |
| ref->base = build2 (MEM_REF, char_type_node, |
| ptr, null_pointer_node); |
| ref->offset = 0; |
| } |
| ref->offset += extra_offset; |
| if (size |
| && tree_fits_shwi_p (size) |
| && (size_hwi = tree_to_shwi (size)) <= HOST_WIDE_INT_MAX / BITS_PER_UNIT) |
| ref->max_size = ref->size = size_hwi * BITS_PER_UNIT; |
| else |
| ref->max_size = ref->size = -1; |
| ref->ref_alias_set = 0; |
| ref->base_alias_set = 0; |
| ref->volatile_p = false; |
| } |
| |
| /* Return 1 if TYPE1 and TYPE2 are to be considered equivalent for the |
| purpose of TBAA. Return 0 if they are distinct and -1 if we cannot |
| decide. */ |
| |
| static inline int |
| same_type_for_tbaa (tree type1, tree type2) |
| { |
| type1 = TYPE_MAIN_VARIANT (type1); |
| type2 = TYPE_MAIN_VARIANT (type2); |
| |
| /* If we would have to do structural comparison bail out. */ |
| if (TYPE_STRUCTURAL_EQUALITY_P (type1) |
| || TYPE_STRUCTURAL_EQUALITY_P (type2)) |
| return -1; |
| |
| /* Compare the canonical types. */ |
| if (TYPE_CANONICAL (type1) == TYPE_CANONICAL (type2)) |
| return 1; |
| |
| /* ??? Array types are not properly unified in all cases as we have |
| spurious changes in the index types for example. Removing this |
| causes all sorts of problems with the Fortran frontend. */ |
| if (TREE_CODE (type1) == ARRAY_TYPE |
| && TREE_CODE (type2) == ARRAY_TYPE) |
| return -1; |
| |
| /* ??? In Ada, an lvalue of an unconstrained type can be used to access an |
| object of one of its constrained subtypes, e.g. when a function with an |
| unconstrained parameter passed by reference is called on an object and |
| inlined. But, even in the case of a fixed size, type and subtypes are |
| not equivalent enough as to share the same TYPE_CANONICAL, since this |
| would mean that conversions between them are useless, whereas they are |
| not (e.g. type and subtypes can have different modes). So, in the end, |
| they are only guaranteed to have the same alias set. */ |
| if (get_alias_set (type1) == get_alias_set (type2)) |
| return -1; |
| |
| /* The types are known to be not equal. */ |
| return 0; |
| } |
| |
| /* Determine if the two component references REF1 and REF2 which are |
| based on access types TYPE1 and TYPE2 and of which at least one is based |
| on an indirect reference may alias. REF2 is the only one that can |
| be a decl in which case REF2_IS_DECL is true. |
| REF1_ALIAS_SET, BASE1_ALIAS_SET, REF2_ALIAS_SET and BASE2_ALIAS_SET |
| are the respective alias sets. */ |
| |
| static bool |
| aliasing_component_refs_p (tree ref1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| tree ref2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| bool ref2_is_decl) |
| { |
| /* If one reference is a component references through pointers try to find a |
| common base and apply offset based disambiguation. This handles |
| for example |
| struct A { int i; int j; } *q; |
| struct B { struct A a; int k; } *p; |
| disambiguating q->i and p->a.j. */ |
| tree base1, base2; |
| tree type1, type2; |
| tree *refp; |
| int same_p; |
| |
| /* Choose bases and base types to search for. */ |
| base1 = ref1; |
| while (handled_component_p (base1)) |
| base1 = TREE_OPERAND (base1, 0); |
| type1 = TREE_TYPE (base1); |
| base2 = ref2; |
| while (handled_component_p (base2)) |
| base2 = TREE_OPERAND (base2, 0); |
| type2 = TREE_TYPE (base2); |
| |
| /* Now search for the type1 in the access path of ref2. This |
| would be a common base for doing offset based disambiguation on. */ |
| refp = &ref2; |
| while (handled_component_p (*refp) |
| && same_type_for_tbaa (TREE_TYPE (*refp), type1) == 0) |
| refp = &TREE_OPERAND (*refp, 0); |
| same_p = same_type_for_tbaa (TREE_TYPE (*refp), type1); |
| /* If we couldn't compare types we have to bail out. */ |
| if (same_p == -1) |
| return true; |
| else if (same_p == 1) |
| { |
| HOST_WIDE_INT offadj, sztmp, msztmp; |
| bool reverse; |
| get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp, &reverse); |
| offset2 -= offadj; |
| get_ref_base_and_extent (base1, &offadj, &sztmp, &msztmp, &reverse); |
| offset1 -= offadj; |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| /* If we didn't find a common base, try the other way around. */ |
| refp = &ref1; |
| while (handled_component_p (*refp) |
| && same_type_for_tbaa (TREE_TYPE (*refp), type2) == 0) |
| refp = &TREE_OPERAND (*refp, 0); |
| same_p = same_type_for_tbaa (TREE_TYPE (*refp), type2); |
| /* If we couldn't compare types we have to bail out. */ |
| if (same_p == -1) |
| return true; |
| else if (same_p == 1) |
| { |
| HOST_WIDE_INT offadj, sztmp, msztmp; |
| bool reverse; |
| get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp, &reverse); |
| offset1 -= offadj; |
| get_ref_base_and_extent (base2, &offadj, &sztmp, &msztmp, &reverse); |
| offset2 -= offadj; |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| |
| /* If we have two type access paths B1.path1 and B2.path2 they may |
| only alias if either B1 is in B2.path2 or B2 is in B1.path1. |
| But we can still have a path that goes B1.path1...B2.path2 with |
| a part that we do not see. So we can only disambiguate now |
| if there is no B2 in the tail of path1 and no B1 on the |
| tail of path2. */ |
| if (base1_alias_set == ref2_alias_set |
| || alias_set_subset_of (base1_alias_set, ref2_alias_set)) |
| return true; |
| /* If this is ptr vs. decl then we know there is no ptr ... decl path. */ |
| if (!ref2_is_decl) |
| return (base2_alias_set == ref1_alias_set |
| || alias_set_subset_of (base2_alias_set, ref1_alias_set)); |
| return false; |
| } |
| |
| /* Return true if we can determine that component references REF1 and REF2, |
| that are within a common DECL, cannot overlap. */ |
| |
| static bool |
| nonoverlapping_component_refs_of_decl_p (tree ref1, tree ref2) |
| { |
| auto_vec<tree, 16> component_refs1; |
| auto_vec<tree, 16> component_refs2; |
| |
| /* Create the stack of handled components for REF1. */ |
| while (handled_component_p (ref1)) |
| { |
| component_refs1.safe_push (ref1); |
| ref1 = TREE_OPERAND (ref1, 0); |
| } |
| if (TREE_CODE (ref1) == MEM_REF) |
| { |
| if (!integer_zerop (TREE_OPERAND (ref1, 1))) |
| return false; |
| ref1 = TREE_OPERAND (TREE_OPERAND (ref1, 0), 0); |
| } |
| |
| /* Create the stack of handled components for REF2. */ |
| while (handled_component_p (ref2)) |
| { |
| component_refs2.safe_push (ref2); |
| ref2 = TREE_OPERAND (ref2, 0); |
| } |
| if (TREE_CODE (ref2) == MEM_REF) |
| { |
| if (!integer_zerop (TREE_OPERAND (ref2, 1))) |
| return false; |
| ref2 = TREE_OPERAND (TREE_OPERAND (ref2, 0), 0); |
| } |
| |
| /* Bases must be either same or uncomparable. */ |
| gcc_checking_assert (ref1 == ref2 |
| || (DECL_P (ref1) && DECL_P (ref2) |
| && compare_base_decls (ref1, ref2) != 0)); |
| |
| /* Pop the stacks in parallel and examine the COMPONENT_REFs of the same |
| rank. This is sufficient because we start from the same DECL and you |
| cannot reference several fields at a time with COMPONENT_REFs (unlike |
| with ARRAY_RANGE_REFs for arrays) so you always need the same number |
| of them to access a sub-component, unless you're in a union, in which |
| case the return value will precisely be false. */ |
| while (true) |
| { |
| do |
| { |
| if (component_refs1.is_empty ()) |
| return false; |
| ref1 = component_refs1.pop (); |
| } |
| while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref1, 0)))); |
| |
| do |
| { |
| if (component_refs2.is_empty ()) |
| return false; |
| ref2 = component_refs2.pop (); |
| } |
| while (!RECORD_OR_UNION_TYPE_P (TREE_TYPE (TREE_OPERAND (ref2, 0)))); |
| |
| /* Beware of BIT_FIELD_REF. */ |
| if (TREE_CODE (ref1) != COMPONENT_REF |
| || TREE_CODE (ref2) != COMPONENT_REF) |
| return false; |
| |
| tree field1 = TREE_OPERAND (ref1, 1); |
| tree field2 = TREE_OPERAND (ref2, 1); |
| |
| /* ??? We cannot simply use the type of operand #0 of the refs here |
| as the Fortran compiler smuggles type punning into COMPONENT_REFs |
| for common blocks instead of using unions like everyone else. */ |
| tree type1 = DECL_CONTEXT (field1); |
| tree type2 = DECL_CONTEXT (field2); |
| |
| /* We cannot disambiguate fields in a union or qualified union. */ |
| if (type1 != type2 || TREE_CODE (type1) != RECORD_TYPE) |
| return false; |
| |
| if (field1 != field2) |
| { |
| /* A field and its representative need to be considered the |
| same. */ |
| if (DECL_BIT_FIELD_REPRESENTATIVE (field1) == field2 |
| || DECL_BIT_FIELD_REPRESENTATIVE (field2) == field1) |
| return false; |
| /* Different fields of the same record type cannot overlap. |
| ??? Bitfields can overlap at RTL level so punt on them. */ |
| if (DECL_BIT_FIELD (field1) && DECL_BIT_FIELD (field2)) |
| return false; |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* qsort compare function to sort FIELD_DECLs after their |
| DECL_FIELD_CONTEXT TYPE_UID. */ |
| |
| static inline int |
| ncr_compar (const void *field1_, const void *field2_) |
| { |
| const_tree field1 = *(const_tree *) const_cast <void *>(field1_); |
| const_tree field2 = *(const_tree *) const_cast <void *>(field2_); |
| unsigned int uid1 = TYPE_UID (DECL_FIELD_CONTEXT (field1)); |
| unsigned int uid2 = TYPE_UID (DECL_FIELD_CONTEXT (field2)); |
| if (uid1 < uid2) |
| return -1; |
| else if (uid1 > uid2) |
| return 1; |
| return 0; |
| } |
| |
| /* Return true if we can determine that the fields referenced cannot |
| overlap for any pair of objects. */ |
| |
| static bool |
| nonoverlapping_component_refs_p (const_tree x, const_tree y) |
| { |
| if (!flag_strict_aliasing |
| || !x || !y |
| || TREE_CODE (x) != COMPONENT_REF |
| || TREE_CODE (y) != COMPONENT_REF) |
| return false; |
| |
| auto_vec<const_tree, 16> fieldsx; |
| while (TREE_CODE (x) == COMPONENT_REF) |
| { |
| tree field = TREE_OPERAND (x, 1); |
| tree type = DECL_FIELD_CONTEXT (field); |
| if (TREE_CODE (type) == RECORD_TYPE) |
| fieldsx.safe_push (field); |
| x = TREE_OPERAND (x, 0); |
| } |
| if (fieldsx.length () == 0) |
| return false; |
| auto_vec<const_tree, 16> fieldsy; |
| while (TREE_CODE (y) == COMPONENT_REF) |
| { |
| tree field = TREE_OPERAND (y, 1); |
| tree type = DECL_FIELD_CONTEXT (field); |
| if (TREE_CODE (type) == RECORD_TYPE) |
| fieldsy.safe_push (TREE_OPERAND (y, 1)); |
| y = TREE_OPERAND (y, 0); |
| } |
| if (fieldsy.length () == 0) |
| return false; |
| |
| /* Most common case first. */ |
| if (fieldsx.length () == 1 |
| && fieldsy.length () == 1) |
| return ((DECL_FIELD_CONTEXT (fieldsx[0]) |
| == DECL_FIELD_CONTEXT (fieldsy[0])) |
| && fieldsx[0] != fieldsy[0] |
| && !(DECL_BIT_FIELD (fieldsx[0]) && DECL_BIT_FIELD (fieldsy[0]))); |
| |
| if (fieldsx.length () == 2) |
| { |
| if (ncr_compar (&fieldsx[0], &fieldsx[1]) == 1) |
| std::swap (fieldsx[0], fieldsx[1]); |
| } |
| else |
| fieldsx.qsort (ncr_compar); |
| |
| if (fieldsy.length () == 2) |
| { |
| if (ncr_compar (&fieldsy[0], &fieldsy[1]) == 1) |
| std::swap (fieldsy[0], fieldsy[1]); |
| } |
| else |
| fieldsy.qsort (ncr_compar); |
| |
| unsigned i = 0, j = 0; |
| do |
| { |
| const_tree fieldx = fieldsx[i]; |
| const_tree fieldy = fieldsy[j]; |
| tree typex = DECL_FIELD_CONTEXT (fieldx); |
| tree typey = DECL_FIELD_CONTEXT (fieldy); |
| if (typex == typey) |
| { |
| /* We're left with accessing different fields of a structure, |
| no possible overlap. */ |
| if (fieldx != fieldy) |
| { |
| /* A field and its representative need to be considered the |
| same. */ |
| if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx) == fieldy |
| || DECL_BIT_FIELD_REPRESENTATIVE (fieldy) == fieldx) |
| return false; |
| /* Different fields of the same record type cannot overlap. |
| ??? Bitfields can overlap at RTL level so punt on them. */ |
| if (DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy)) |
| return false; |
| return true; |
| } |
| } |
| if (TYPE_UID (typex) < TYPE_UID (typey)) |
| { |
| i++; |
| if (i == fieldsx.length ()) |
| break; |
| } |
| else |
| { |
| j++; |
| if (j == fieldsy.length ()) |
| break; |
| } |
| } |
| while (1); |
| |
| return false; |
| } |
| |
| |
| /* Return true if two memory references based on the variables BASE1 |
| and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
| [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2 |
| if non-NULL are the complete memory reference trees. */ |
| |
| static bool |
| decl_refs_may_alias_p (tree ref1, tree base1, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| tree ref2, tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2) |
| { |
| gcc_checking_assert (DECL_P (base1) && DECL_P (base2)); |
| |
| /* If both references are based on different variables, they cannot alias. */ |
| if (compare_base_decls (base1, base2) == 0) |
| return false; |
| |
| /* If both references are based on the same variable, they cannot alias if |
| the accesses do not overlap. */ |
| if (!ranges_overlap_p (offset1, max_size1, offset2, max_size2)) |
| return false; |
| |
| /* For components with variable position, the above test isn't sufficient, |
| so we disambiguate component references manually. */ |
| if (ref1 && ref2 |
| && handled_component_p (ref1) && handled_component_p (ref2) |
| && nonoverlapping_component_refs_of_decl_p (ref1, ref2)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Return true if an indirect reference based on *PTR1 constrained |
| to [OFFSET1, OFFSET1 + MAX_SIZE1) may alias a variable based on BASE2 |
| constrained to [OFFSET2, OFFSET2 + MAX_SIZE2). *PTR1 and BASE2 have |
| the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
| in which case they are computed on-demand. REF1 and REF2 |
| if non-NULL are the complete memory reference trees. */ |
| |
| static bool |
| indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1, |
| HOST_WIDE_INT offset1, |
| HOST_WIDE_INT max_size1 ATTRIBUTE_UNUSED, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2 ATTRIBUTE_UNUSED, tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, bool tbaa_p) |
| { |
| tree ptr1; |
| tree ptrtype1, dbase2; |
| HOST_WIDE_INT offset1p = offset1, offset2p = offset2; |
| HOST_WIDE_INT doffset1, doffset2; |
| |
| gcc_checking_assert ((TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF) |
| && DECL_P (base2)); |
| |
| ptr1 = TREE_OPERAND (base1, 0); |
| |
| /* The offset embedded in MEM_REFs can be negative. Bias them |
| so that the resulting offset adjustment is positive. */ |
| offset_int moff = mem_ref_offset (base1); |
| moff <<= LOG2_BITS_PER_UNIT; |
| if (wi::neg_p (moff)) |
| offset2p += (-moff).to_short_addr (); |
| else |
| offset1p += moff.to_short_addr (); |
| |
| /* If only one reference is based on a variable, they cannot alias if |
| the pointer access is beyond the extent of the variable access. |
| (the pointer base cannot validly point to an offset less than zero |
| of the variable). |
| ??? IVOPTs creates bases that do not honor this restriction, |
| so do not apply this optimization for TARGET_MEM_REFs. */ |
| if (TREE_CODE (base1) != TARGET_MEM_REF |
| && !ranges_overlap_p (MAX (0, offset1p), -1, offset2p, max_size2)) |
| return false; |
| /* They also cannot alias if the pointer may not point to the decl. */ |
| if (!ptr_deref_may_alias_decl_p (ptr1, base2)) |
| return false; |
| |
| /* Disambiguations that rely on strict aliasing rules follow. */ |
| if (!flag_strict_aliasing || !tbaa_p) |
| return true; |
| |
| ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); |
| |
| /* If the alias set for a pointer access is zero all bets are off. */ |
| if (base1_alias_set == 0) |
| return true; |
| |
| /* When we are trying to disambiguate an access with a pointer dereference |
| as base versus one with a decl as base we can use both the size |
| of the decl and its dynamic type for extra disambiguation. |
| ??? We do not know anything about the dynamic type of the decl |
| other than that its alias-set contains base2_alias_set as a subset |
| which does not help us here. */ |
| /* As we know nothing useful about the dynamic type of the decl just |
| use the usual conflict check rather than a subset test. |
| ??? We could introduce -fvery-strict-aliasing when the language |
| does not allow decls to have a dynamic type that differs from their |
| static type. Then we can check |
| !alias_set_subset_of (base1_alias_set, base2_alias_set) instead. */ |
| if (base1_alias_set != base2_alias_set |
| && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) |
| return false; |
| /* If the size of the access relevant for TBAA through the pointer |
| is bigger than the size of the decl we can't possibly access the |
| decl via that pointer. */ |
| if (DECL_SIZE (base2) && COMPLETE_TYPE_P (TREE_TYPE (ptrtype1)) |
| && TREE_CODE (DECL_SIZE (base2)) == INTEGER_CST |
| && TREE_CODE (TYPE_SIZE (TREE_TYPE (ptrtype1))) == INTEGER_CST |
| /* ??? This in turn may run afoul when a decl of type T which is |
| a member of union type U is accessed through a pointer to |
| type U and sizeof T is smaller than sizeof U. */ |
| && TREE_CODE (TREE_TYPE (ptrtype1)) != UNION_TYPE |
| && TREE_CODE (TREE_TYPE (ptrtype1)) != QUAL_UNION_TYPE |
| && tree_int_cst_lt (DECL_SIZE (base2), TYPE_SIZE (TREE_TYPE (ptrtype1)))) |
| return false; |
| |
| if (!ref2) |
| return true; |
| |
| /* If the decl is accessed via a MEM_REF, reconstruct the base |
| we can use for TBAA and an appropriately adjusted offset. */ |
| dbase2 = ref2; |
| while (handled_component_p (dbase2)) |
| dbase2 = TREE_OPERAND (dbase2, 0); |
| doffset1 = offset1; |
| doffset2 = offset2; |
| if (TREE_CODE (dbase2) == MEM_REF |
| || TREE_CODE (dbase2) == TARGET_MEM_REF) |
| { |
| offset_int moff = mem_ref_offset (dbase2); |
| moff <<= LOG2_BITS_PER_UNIT; |
| if (wi::neg_p (moff)) |
| doffset1 -= (-moff).to_short_addr (); |
| else |
| doffset2 -= moff.to_short_addr (); |
| } |
| |
| /* If either reference is view-converted, give up now. */ |
| if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1 |
| || same_type_for_tbaa (TREE_TYPE (dbase2), TREE_TYPE (base2)) != 1) |
| return true; |
| |
| /* If both references are through the same type, they do not alias |
| if the accesses do not overlap. This does extra disambiguation |
| for mixed/pointer accesses but requires strict aliasing. |
| For MEM_REFs we require that the component-ref offset we computed |
| is relative to the start of the type which we ensure by |
| comparing rvalue and access type and disregarding the constant |
| pointer offset. */ |
| if ((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (dbase2)) == 1) |
| return ranges_overlap_p (doffset1, max_size1, doffset2, max_size2); |
| |
| if (ref1 && ref2 |
| && nonoverlapping_component_refs_p (ref1, ref2)) |
| return false; |
| |
| /* Do access-path based disambiguation. */ |
| if (ref1 && ref2 |
| && (handled_component_p (ref1) || handled_component_p (ref2))) |
| return aliasing_component_refs_p (ref1, |
| ref1_alias_set, base1_alias_set, |
| offset1, max_size1, |
| ref2, |
| ref2_alias_set, base2_alias_set, |
| offset2, max_size2, true); |
| |
| return true; |
| } |
| |
| /* Return true if two indirect references based on *PTR1 |
| and *PTR2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and |
| [OFFSET2, OFFSET2 + MAX_SIZE2) may alias. *PTR1 and *PTR2 have |
| the alias sets BASE1_ALIAS_SET and BASE2_ALIAS_SET which can be -1 |
| in which case they are computed on-demand. REF1 and REF2 |
| if non-NULL are the complete memory reference trees. */ |
| |
| static bool |
| indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1, |
| HOST_WIDE_INT offset1, HOST_WIDE_INT max_size1, |
| alias_set_type ref1_alias_set, |
| alias_set_type base1_alias_set, |
| tree ref2 ATTRIBUTE_UNUSED, tree base2, |
| HOST_WIDE_INT offset2, HOST_WIDE_INT max_size2, |
| alias_set_type ref2_alias_set, |
| alias_set_type base2_alias_set, bool tbaa_p) |
| { |
| tree ptr1; |
| tree ptr2; |
| tree ptrtype1, ptrtype2; |
| |
| gcc_checking_assert ((TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF) |
| && (TREE_CODE (base2) == MEM_REF |
| || TREE_CODE (base2) == TARGET_MEM_REF)); |
| |
| ptr1 = TREE_OPERAND (base1, 0); |
| ptr2 = TREE_OPERAND (base2, 0); |
| |
| /* If both bases are based on pointers they cannot alias if they may not |
| point to the same memory object or if they point to the same object |
| and the accesses do not overlap. */ |
| if ((!cfun || gimple_in_ssa_p (cfun)) |
| && operand_equal_p (ptr1, ptr2, 0) |
| && (((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && (TREE_CODE (base2) != TARGET_MEM_REF |
| || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2)))) |
| || (TREE_CODE (base1) == TARGET_MEM_REF |
| && TREE_CODE (base2) == TARGET_MEM_REF |
| && (TMR_STEP (base1) == TMR_STEP (base2) |
| || (TMR_STEP (base1) && TMR_STEP (base2) |
| && operand_equal_p (TMR_STEP (base1), |
| TMR_STEP (base2), 0))) |
| && (TMR_INDEX (base1) == TMR_INDEX (base2) |
| || (TMR_INDEX (base1) && TMR_INDEX (base2) |
| && operand_equal_p (TMR_INDEX (base1), |
| TMR_INDEX (base2), 0))) |
| && (TMR_INDEX2 (base1) == TMR_INDEX2 (base2) |
| || (TMR_INDEX2 (base1) && TMR_INDEX2 (base2) |
| && operand_equal_p (TMR_INDEX2 (base1), |
| TMR_INDEX2 (base2), 0)))))) |
| { |
| offset_int moff; |
| /* The offset embedded in MEM_REFs can be negative. Bias them |
| so that the resulting offset adjustment is positive. */ |
| moff = mem_ref_offset (base1); |
| moff <<= LOG2_BITS_PER_UNIT; |
| if (wi::neg_p (moff)) |
| offset2 += (-moff).to_short_addr (); |
| else |
| offset1 += moff.to_shwi (); |
| moff = mem_ref_offset (base2); |
| moff <<= LOG2_BITS_PER_UNIT; |
| if (wi::neg_p (moff)) |
| offset1 += (-moff).to_short_addr (); |
| else |
| offset2 += moff.to_short_addr (); |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| } |
| if (!ptr_derefs_may_alias_p (ptr1, ptr2)) |
| return false; |
| |
| /* Disambiguations that rely on strict aliasing rules follow. */ |
| if (!flag_strict_aliasing || !tbaa_p) |
| return true; |
| |
| ptrtype1 = TREE_TYPE (TREE_OPERAND (base1, 1)); |
| ptrtype2 = TREE_TYPE (TREE_OPERAND (base2, 1)); |
| |
| /* If the alias set for a pointer access is zero all bets are off. */ |
| if (base1_alias_set == 0 |
| || base2_alias_set == 0) |
| return true; |
| |
| /* If both references are through the same type, they do not alias |
| if the accesses do not overlap. This does extra disambiguation |
| for mixed/pointer accesses but requires strict aliasing. */ |
| if ((TREE_CODE (base1) != TARGET_MEM_REF |
| || (!TMR_INDEX (base1) && !TMR_INDEX2 (base1))) |
| && (TREE_CODE (base2) != TARGET_MEM_REF |
| || (!TMR_INDEX (base2) && !TMR_INDEX2 (base2))) |
| && same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1 |
| && same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1 |
| && same_type_for_tbaa (TREE_TYPE (ptrtype1), |
| TREE_TYPE (ptrtype2)) == 1 |
| /* But avoid treating arrays as "objects", instead assume they |
| can overlap by an exact multiple of their element size. */ |
| && TREE_CODE (TREE_TYPE (ptrtype1)) != ARRAY_TYPE) |
| return ranges_overlap_p (offset1, max_size1, offset2, max_size2); |
| |
| /* Do type-based disambiguation. */ |
| if (base1_alias_set != base2_alias_set |
| && !alias_sets_conflict_p (base1_alias_set, base2_alias_set)) |
| return false; |
| |
| /* If either reference is view-converted, give up now. */ |
| if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1 |
| || same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) != 1) |
| return true; |
| |
| if (ref1 && ref2 |
| && nonoverlapping_component_refs_p (ref1, ref2)) |
| return false; |
| |
| /* Do access-path based disambiguation. */ |
| if (ref1 && ref2 |
| && (handled_component_p (ref1) || handled_component_p (ref2))) |
| return aliasing_component_refs_p (ref1, |
| ref1_alias_set, base1_alias_set, |
| offset1, max_size1, |
| ref2, |
| ref2_alias_set, base2_alias_set, |
| offset2, max_size2, false); |
| |
| return true; |
| } |
| |
| /* Return true, if the two memory references REF1 and REF2 may alias. */ |
| |
| bool |
| refs_may_alias_p_1 (ao_ref *ref1, ao_ref *ref2, bool tbaa_p) |
| { |
| tree base1, base2; |
| HOST_WIDE_INT offset1 = 0, offset2 = 0; |
| HOST_WIDE_INT max_size1 = -1, max_size2 = -1; |
| bool var1_p, var2_p, ind1_p, ind2_p; |
| |
| gcc_checking_assert ((!ref1->ref |
| || TREE_CODE (ref1->ref) == SSA_NAME |
| || DECL_P (ref1->ref) |
| || TREE_CODE (ref1->ref) == STRING_CST |
| || handled_component_p (ref1->ref) |
| || TREE_CODE (ref1->ref) == MEM_REF |
| || TREE_CODE (ref1->ref) == TARGET_MEM_REF) |
| && (!ref2->ref |
| || TREE_CODE (ref2->ref) == SSA_NAME |
| || DECL_P (ref2->ref) |
| || TREE_CODE (ref2->ref) == STRING_CST |
| || handled_component_p (ref2->ref) |
| || TREE_CODE (ref2->ref) == MEM_REF |
| || TREE_CODE (ref2->ref) == TARGET_MEM_REF)); |
| |
| /* Decompose the references into their base objects and the access. */ |
| base1 = ao_ref_base (ref1); |
| offset1 = ref1->offset; |
| max_size1 = ref1->max_size; |
| base2 = ao_ref_base (ref2); |
| offset2 = ref2->offset; |
| max_size2 = ref2->max_size; |
| |
| /* We can end up with registers or constants as bases for example from |
| *D.1663_44 = VIEW_CONVERT_EXPR<struct DB_LSN>(__tmp$B0F64_59); |
| which is seen as a struct copy. */ |
| if (TREE_CODE (base1) == SSA_NAME |
| || TREE_CODE (base1) == CONST_DECL |
| || TREE_CODE (base1) == CONSTRUCTOR |
| || TREE_CODE (base1) == ADDR_EXPR |
| || CONSTANT_CLASS_P (base1) |
| || TREE_CODE (base2) == SSA_NAME |
| || TREE_CODE (base2) == CONST_DECL |
| || TREE_CODE (base2) == CONSTRUCTOR |
| || TREE_CODE (base2) == ADDR_EXPR |
| || CONSTANT_CLASS_P (base2)) |
| return false; |
| |
| /* We can end up referring to code via function and label decls. |
| As we likely do not properly track code aliases conservatively |
| bail out. */ |
| if (TREE_CODE (base1) == FUNCTION_DECL |
| || TREE_CODE (base1) == LABEL_DECL |
| || TREE_CODE (base2) == FUNCTION_DECL |
| || TREE_CODE (base2) == LABEL_DECL) |
| return true; |
| |
| /* Two volatile accesses always conflict. */ |
| if (ref1->volatile_p |
| && ref2->volatile_p) |
| return true; |
| |
| /* Defer to simple offset based disambiguation if we have |
| references based on two decls. Do this before defering to |
| TBAA to handle must-alias cases in conformance with the |
| GCC extension of allowing type-punning through unions. */ |
| var1_p = DECL_P (base1); |
| var2_p = DECL_P (base2); |
| if (var1_p && var2_p) |
| return decl_refs_may_alias_p (ref1->ref, base1, offset1, max_size1, |
| ref2->ref, base2, offset2, max_size2); |
| |
| /* Handle restrict based accesses. |
| ??? ao_ref_base strips inner MEM_REF [&decl], recover from that |
| here. */ |
| tree rbase1 = base1; |
| tree rbase2 = base2; |
| if (var1_p) |
| { |
| rbase1 = ref1->ref; |
| if (rbase1) |
| while (handled_component_p (rbase1)) |
| rbase1 = TREE_OPERAND (rbase1, 0); |
| } |
| if (var2_p) |
| { |
| rbase2 = ref2->ref; |
| if (rbase2) |
| while (handled_component_p (rbase2)) |
| rbase2 = TREE_OPERAND (rbase2, 0); |
| } |
| if (rbase1 && rbase2 |
| && (TREE_CODE (base1) == MEM_REF || TREE_CODE (base1) == TARGET_MEM_REF) |
| && (TREE_CODE (base2) == MEM_REF || TREE_CODE (base2) == TARGET_MEM_REF) |
| /* If the accesses are in the same restrict clique... */ |
| && MR_DEPENDENCE_CLIQUE (base1) == MR_DEPENDENCE_CLIQUE (base2) |
| /* But based on different pointers they do not alias. */ |
| && MR_DEPENDENCE_BASE (base1) != MR_DEPENDENCE_BASE (base2)) |
| return false; |
| |
| ind1_p = (TREE_CODE (base1) == MEM_REF |
| || TREE_CODE (base1) == TARGET_MEM_REF); |
| ind2_p = (TREE_CODE (base2) == MEM_REF |
| || TREE_CODE (base2) == TARGET_MEM_REF); |
| |
| /* Canonicalize the pointer-vs-decl case. */ |
| if (ind1_p && var2_p) |
| { |
| std::swap (offset1, offset2); |
| std::swap (max_size1, max_size2); |
| std::swap (base1, base2); |
| std::swap (ref1, ref2); |
| var1_p = true; |
| ind1_p = false; |
| var2_p = false; |
| ind2_p = true; |
| } |
| |
| /* First defer to TBAA if possible. */ |
| if (tbaa_p |
| && flag_strict_aliasing |
| && !alias_sets_conflict_p (ao_ref_alias_set (ref1), |
| ao_ref_alias_set (ref2))) |
| return false; |
| |
| /* Dispatch to the pointer-vs-decl or pointer-vs-pointer disambiguators. */ |
| if (var1_p && ind2_p) |
| return indirect_ref_may_alias_decl_p (ref2->ref, base2, |
| offset2, max_size2, |
| ao_ref_alias_set (ref2), |
| ao_ref_base_alias_set (ref2), |
| ref1->ref, base1, |
| offset1, max_size1, |
| ao_ref_alias_set (ref1), |
| ao_ref_base_alias_set (ref1), |
| tbaa_p); |
| else if (ind1_p && ind2_p) |
| return indirect_refs_may_alias_p (ref1->ref, base1, |
| offset1, max_size1, |
| ao_ref_alias_set (ref1), |
| ao_ref_base_alias_set (ref1), |
| ref2->ref, base2, |
| offset2, max_size2, |
| ao_ref_alias_set (ref2), |
| ao_ref_base_alias_set (ref2), |
| tbaa_p); |
| |
| gcc_unreachable (); |
| } |
| |
| static bool |
| refs_may_alias_p (tree ref1, ao_ref *ref2) |
| { |
| ao_ref r1; |
| ao_ref_init (&r1, ref1); |
| return refs_may_alias_p_1 (&r1, ref2, true); |
| } |
| |
| bool |
| refs_may_alias_p (tree ref1, tree ref2) |
| { |
| ao_ref r1, r2; |
| bool res; |
| ao_ref_init (&r1, ref1); |
| ao_ref_init (&r2, ref2); |
| res = refs_may_alias_p_1 (&r1, &r2, true); |
| if (res) |
| ++alias_stats.refs_may_alias_p_may_alias; |
| else |
| ++alias_stats.refs_may_alias_p_no_alias; |
| return res; |
| } |
| |
| /* Returns true if there is a anti-dependence for the STORE that |
| executes after the LOAD. */ |
| |
| bool |
| refs_anti_dependent_p (tree load, tree store) |
| { |
| ao_ref r1, r2; |
| ao_ref_init (&r1, load); |
| ao_ref_init (&r2, store); |
| return refs_may_alias_p_1 (&r1, &r2, false); |
| } |
| |
| /* Returns true if there is a output dependence for the stores |
| STORE1 and STORE2. */ |
| |
| bool |
| refs_output_dependent_p (tree store1, tree store2) |
| { |
| ao_ref r1, r2; |
| ao_ref_init (&r1, store1); |
| ao_ref_init (&r2, store2); |
| return refs_may_alias_p_1 (&r1, &r2, false); |
| } |
| |
| /* If the call CALL may use the memory reference REF return true, |
| otherwise return false. */ |
| |
| static bool |
| ref_maybe_used_by_call_p_1 (gcall *call, ao_ref *ref) |
| { |
| tree base, callee; |
| unsigned i; |
| int flags = gimple_call_flags (call); |
| |
| /* Const functions without a static chain do not implicitly use memory. */ |
| if (!gimple_call_chain (call) |
| && (flags & (ECF_CONST|ECF_NOVOPS))) |
| goto process_args; |
| |
| base = ao_ref_base (ref); |
| if (!base) |
| return true; |
| |
| /* A call that is not without side-effects might involve volatile |
| accesses and thus conflicts with all other volatile accesses. */ |
| if (ref->volatile_p) |
| return true; |
| |
| /* If the reference is based on a decl that is not aliased the call |
| cannot possibly use it. */ |
| if (DECL_P (base) |
| && !may_be_aliased (base) |
| /* But local statics can be used through recursion. */ |
| && !is_global_var (base)) |
| goto process_args; |
| |
| callee = gimple_call_fndecl (call); |
| |
| /* Handle those builtin functions explicitly that do not act as |
| escape points. See tree-ssa-structalias.c:find_func_aliases |
| for the list of builtins we might need to handle here. */ |
| if (callee != NULL_TREE |
| && gimple_call_builtin_p (call, BUILT_IN_NORMAL)) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| /* All the following functions read memory pointed to by |
| their second argument. strcat/strncat additionally |
| reads memory pointed to by the first argument. */ |
| case BUILT_IN_STRCAT: |
| case BUILT_IN_STRNCAT: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| NULL_TREE); |
| if (refs_may_alias_p_1 (&dref, ref, false)) |
| return true; |
| } |
| /* FALLTHRU */ |
| case BUILT_IN_STRCPY: |
| case BUILT_IN_STRNCPY: |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMMOVE: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPNCPY: |
| case BUILT_IN_TM_MEMCPY: |
| case BUILT_IN_TM_MEMMOVE: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| if (gimple_call_num_args (call) == 3) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_STRCAT_CHK: |
| case BUILT_IN_STRNCAT_CHK: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| NULL_TREE); |
| if (refs_may_alias_p_1 (&dref, ref, false)) |
| return true; |
| } |
| /* FALLTHRU */ |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STRNCPY_CHK: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMMOVE_CHK: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STPNCPY_CHK: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| if (gimple_call_num_args (call) == 4) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_BCOPY: |
| { |
| ao_ref dref; |
| tree size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| |
| /* The following functions read memory pointed to by their |
| first argument. */ |
| CASE_BUILT_IN_TM_LOAD (1): |
| CASE_BUILT_IN_TM_LOAD (2): |
| CASE_BUILT_IN_TM_LOAD (4): |
| CASE_BUILT_IN_TM_LOAD (8): |
| CASE_BUILT_IN_TM_LOAD (FLOAT): |
| CASE_BUILT_IN_TM_LOAD (DOUBLE): |
| CASE_BUILT_IN_TM_LOAD (LDOUBLE): |
| CASE_BUILT_IN_TM_LOAD (M64): |
| CASE_BUILT_IN_TM_LOAD (M128): |
| CASE_BUILT_IN_TM_LOAD (M256): |
| case BUILT_IN_TM_LOG: |
| case BUILT_IN_TM_LOG_1: |
| case BUILT_IN_TM_LOG_2: |
| case BUILT_IN_TM_LOG_4: |
| case BUILT_IN_TM_LOG_8: |
| case BUILT_IN_TM_LOG_FLOAT: |
| case BUILT_IN_TM_LOG_DOUBLE: |
| case BUILT_IN_TM_LOG_LDOUBLE: |
| case BUILT_IN_TM_LOG_M64: |
| case BUILT_IN_TM_LOG_M128: |
| case BUILT_IN_TM_LOG_M256: |
| return ptr_deref_may_alias_ref_p_1 (gimple_call_arg (call, 0), ref); |
| |
| /* These read memory pointed to by the first argument. */ |
| case BUILT_IN_STRDUP: |
| case BUILT_IN_STRNDUP: |
| case BUILT_IN_REALLOC: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| if (gimple_call_num_args (call) == 2) |
| size = gimple_call_arg (call, 1); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| /* These read memory pointed to by the first argument. */ |
| case BUILT_IN_INDEX: |
| case BUILT_IN_STRCHR: |
| case BUILT_IN_STRRCHR: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| NULL_TREE); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| /* These read memory pointed to by the first argument with size |
| in the third argument. */ |
| case BUILT_IN_MEMCHR: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| gimple_call_arg (call, 2)); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| /* These read memory pointed to by the first and second arguments. */ |
| case BUILT_IN_STRSTR: |
| case BUILT_IN_STRPBRK: |
| { |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| NULL_TREE); |
| if (refs_may_alias_p_1 (&dref, ref, false)) |
| return true; |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| NULL_TREE); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| |
| /* The following builtins do not read from memory. */ |
| case BUILT_IN_FREE: |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_POSIX_MEMALIGN: |
| case BUILT_IN_ALIGNED_ALLOC: |
| case BUILT_IN_CALLOC: |
| case BUILT_IN_ALLOCA: |
| case BUILT_IN_ALLOCA_WITH_ALIGN: |
| case BUILT_IN_STACK_SAVE: |
| case BUILT_IN_STACK_RESTORE: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_TM_MEMSET: |
| case BUILT_IN_MEMSET_CHK: |
| case BUILT_IN_FREXP: |
| case BUILT_IN_FREXPF: |
| case BUILT_IN_FREXPL: |
| case BUILT_IN_GAMMA_R: |
| case BUILT_IN_GAMMAF_R: |
| case BUILT_IN_GAMMAL_R: |
| case BUILT_IN_LGAMMA_R: |
| case BUILT_IN_LGAMMAF_R: |
| case BUILT_IN_LGAMMAL_R: |
| case BUILT_IN_MODF: |
| case BUILT_IN_MODFF: |
| case BUILT_IN_MODFL: |
| case BUILT_IN_REMQUO: |
| case BUILT_IN_REMQUOF: |
| case BUILT_IN_REMQUOL: |
| case BUILT_IN_SINCOS: |
| case BUILT_IN_SINCOSF: |
| case BUILT_IN_SINCOSL: |
| case BUILT_IN_ASSUME_ALIGNED: |
| case BUILT_IN_VA_END: |
| return false; |
| /* __sync_* builtins and some OpenMP builtins act as threading |
| barriers. */ |
| #undef DEF_SYNC_BUILTIN |
| #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM: |
| #include "sync-builtins.def" |
| #undef DEF_SYNC_BUILTIN |
| case BUILT_IN_GOMP_ATOMIC_START: |
| case BUILT_IN_GOMP_ATOMIC_END: |
| case BUILT_IN_GOMP_BARRIER: |
| case BUILT_IN_GOMP_BARRIER_CANCEL: |
| case BUILT_IN_GOMP_TASKWAIT: |
| case BUILT_IN_GOMP_TASKGROUP_END: |
| case BUILT_IN_GOMP_CRITICAL_START: |
| case BUILT_IN_GOMP_CRITICAL_END: |
| case BUILT_IN_GOMP_CRITICAL_NAME_START: |
| case BUILT_IN_GOMP_CRITICAL_NAME_END: |
| case BUILT_IN_GOMP_LOOP_END: |
| case BUILT_IN_GOMP_LOOP_END_CANCEL: |
| case BUILT_IN_GOMP_ORDERED_START: |
| case BUILT_IN_GOMP_ORDERED_END: |
| case BUILT_IN_GOMP_SECTIONS_END: |
| case BUILT_IN_GOMP_SECTIONS_END_CANCEL: |
| case BUILT_IN_GOMP_SINGLE_COPY_START: |
| case BUILT_IN_GOMP_SINGLE_COPY_END: |
| return true; |
| |
| default: |
| /* Fallthru to general call handling. */; |
| } |
| |
| /* Check if base is a global static variable that is not read |
| by the function. */ |
| if (callee != NULL_TREE && VAR_P (base) && TREE_STATIC (base)) |
| { |
| struct cgraph_node *node = cgraph_node::get (callee); |
| bitmap not_read; |
| |
| /* FIXME: Callee can be an OMP builtin that does not have a call graph |
| node yet. We should enforce that there are nodes for all decls in the |
| IL and remove this check instead. */ |
| if (node |
| && (not_read = ipa_reference_get_not_read_global (node)) |
| && bitmap_bit_p (not_read, ipa_reference_var_uid (base))) |
| goto process_args; |
| } |
| |
| /* Check if the base variable is call-used. */ |
| if (DECL_P (base)) |
| { |
| if (pt_solution_includes (gimple_call_use_set (call), base)) |
| return true; |
| } |
| else if ((TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
| if (!pi) |
| return true; |
| |
| if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt)) |
| return true; |
| } |
| else |
| return true; |
| |
| /* Inspect call arguments for passed-by-value aliases. */ |
| process_args: |
| for (i = 0; i < gimple_call_num_args (call); ++i) |
| { |
| tree op = gimple_call_arg (call, i); |
| int flags = gimple_call_arg_flags (call, i); |
| |
| if (flags & EAF_UNUSED) |
| continue; |
| |
| if (TREE_CODE (op) == WITH_SIZE_EXPR) |
| op = TREE_OPERAND (op, 0); |
| |
| if (TREE_CODE (op) != SSA_NAME |
| && !is_gimple_min_invariant (op)) |
| { |
| ao_ref r; |
| ao_ref_init (&r, op); |
| if (refs_may_alias_p_1 (&r, ref, true)) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| static bool |
| ref_maybe_used_by_call_p (gcall *call, ao_ref *ref) |
| { |
| bool res; |
| res = ref_maybe_used_by_call_p_1 (call, ref); |
| if (res) |
| ++alias_stats.ref_maybe_used_by_call_p_may_alias; |
| else |
| ++alias_stats.ref_maybe_used_by_call_p_no_alias; |
| return res; |
| } |
| |
| |
| /* If the statement STMT may use the memory reference REF return |
| true, otherwise return false. */ |
| |
| bool |
| ref_maybe_used_by_stmt_p (gimple *stmt, ao_ref *ref) |
| { |
| if (is_gimple_assign (stmt)) |
| { |
| tree rhs; |
| |
| /* All memory assign statements are single. */ |
| if (!gimple_assign_single_p (stmt)) |
| return false; |
| |
| rhs = gimple_assign_rhs1 (stmt); |
| if (is_gimple_reg (rhs) |
| || is_gimple_min_invariant (rhs) |
| || gimple_assign_rhs_code (stmt) == CONSTRUCTOR) |
| return false; |
| |
| return refs_may_alias_p (rhs, ref); |
| } |
| else if (is_gimple_call (stmt)) |
| return ref_maybe_used_by_call_p (as_a <gcall *> (stmt), ref); |
| else if (greturn *return_stmt = dyn_cast <greturn *> (stmt)) |
| { |
| tree retval = gimple_return_retval (return_stmt); |
| if (retval |
| && TREE_CODE (retval) != SSA_NAME |
| && !is_gimple_min_invariant (retval) |
| && refs_may_alias_p (retval, ref)) |
| return true; |
| /* If ref escapes the function then the return acts as a use. */ |
| tree base = ao_ref_base (ref); |
| if (!base) |
| ; |
| else if (DECL_P (base)) |
| return is_global_var (base); |
| else if (TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0)); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool |
| ref_maybe_used_by_stmt_p (gimple *stmt, tree ref) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return ref_maybe_used_by_stmt_p (stmt, &r); |
| } |
| |
| /* If the call in statement CALL may clobber the memory reference REF |
| return true, otherwise return false. */ |
| |
| bool |
| call_may_clobber_ref_p_1 (gcall *call, ao_ref *ref) |
| { |
| tree base; |
| tree callee; |
| |
| /* If the call is pure or const it cannot clobber anything. */ |
| if (gimple_call_flags (call) |
| & (ECF_PURE|ECF_CONST|ECF_LOOPING_CONST_OR_PURE|ECF_NOVOPS)) |
| return false; |
| if (gimple_call_internal_p (call)) |
| switch (gimple_call_internal_fn (call)) |
| { |
| /* Treat these internal calls like ECF_PURE for aliasing, |
| they don't write to any memory the program should care about. |
| They have important other side-effects, and read memory, |
| so can't be ECF_NOVOPS. */ |
| case IFN_UBSAN_NULL: |
| case IFN_UBSAN_BOUNDS: |
| case IFN_UBSAN_VPTR: |
| case IFN_UBSAN_OBJECT_SIZE: |
| case IFN_ASAN_CHECK: |
| return false; |
| default: |
| break; |
| } |
| |
| base = ao_ref_base (ref); |
| if (!base) |
| return true; |
| |
| if (TREE_CODE (base) == SSA_NAME |
| || CONSTANT_CLASS_P (base)) |
| return false; |
| |
| /* A call that is not without side-effects might involve volatile |
| accesses and thus conflicts with all other volatile accesses. */ |
| if (ref->volatile_p) |
| return true; |
| |
| /* If the reference is based on a decl that is not aliased the call |
| cannot possibly clobber it. */ |
| if (DECL_P (base) |
| && !may_be_aliased (base) |
| /* But local non-readonly statics can be modified through recursion |
| or the call may implement a threading barrier which we must |
| treat as may-def. */ |
| && (TREE_READONLY (base) |
| || !is_global_var (base))) |
| return false; |
| |
| callee = gimple_call_fndecl (call); |
| |
| /* Handle those builtin functions explicitly that do not act as |
| escape points. See tree-ssa-structalias.c:find_func_aliases |
| for the list of builtins we might need to handle here. */ |
| if (callee != NULL_TREE |
| && gimple_call_builtin_p (call, BUILT_IN_NORMAL)) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| /* All the following functions clobber memory pointed to by |
| their first argument. */ |
| case BUILT_IN_STRCPY: |
| case BUILT_IN_STRNCPY: |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMMOVE: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_STPCPY: |
| case BUILT_IN_STPNCPY: |
| case BUILT_IN_STRCAT: |
| case BUILT_IN_STRNCAT: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_TM_MEMSET: |
| CASE_BUILT_IN_TM_STORE (1): |
| CASE_BUILT_IN_TM_STORE (2): |
| CASE_BUILT_IN_TM_STORE (4): |
| CASE_BUILT_IN_TM_STORE (8): |
| CASE_BUILT_IN_TM_STORE (FLOAT): |
| CASE_BUILT_IN_TM_STORE (DOUBLE): |
| CASE_BUILT_IN_TM_STORE (LDOUBLE): |
| CASE_BUILT_IN_TM_STORE (M64): |
| CASE_BUILT_IN_TM_STORE (M128): |
| CASE_BUILT_IN_TM_STORE (M256): |
| case BUILT_IN_TM_MEMCPY: |
| case BUILT_IN_TM_MEMMOVE: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| /* Don't pass in size for strncat, as the maximum size |
| is strlen (dest) + n + 1 instead of n, resp. |
| n + 1 at dest + strlen (dest), but strlen (dest) isn't |
| known. */ |
| if (gimple_call_num_args (call) == 3 |
| && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_STRCPY_CHK: |
| case BUILT_IN_STRNCPY_CHK: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMMOVE_CHK: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_STPCPY_CHK: |
| case BUILT_IN_STPNCPY_CHK: |
| case BUILT_IN_STRCAT_CHK: |
| case BUILT_IN_STRNCAT_CHK: |
| case BUILT_IN_MEMSET_CHK: |
| { |
| ao_ref dref; |
| tree size = NULL_TREE; |
| /* Don't pass in size for __strncat_chk, as the maximum size |
| is strlen (dest) + n + 1 instead of n, resp. |
| n + 1 at dest + strlen (dest), but strlen (dest) isn't |
| known. */ |
| if (gimple_call_num_args (call) == 4 |
| && DECL_FUNCTION_CODE (callee) != BUILT_IN_STRNCAT_CHK) |
| size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 0), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| case BUILT_IN_BCOPY: |
| { |
| ao_ref dref; |
| tree size = gimple_call_arg (call, 2); |
| ao_ref_init_from_ptr_and_size (&dref, |
| gimple_call_arg (call, 1), |
| size); |
| return refs_may_alias_p_1 (&dref, ref, false); |
| } |
| /* Allocating memory does not have any side-effects apart from |
| being the definition point for the pointer. */ |
| case BUILT_IN_MALLOC: |
| case BUILT_IN_ALIGNED_ALLOC: |
| case BUILT_IN_CALLOC: |
| case BUILT_IN_STRDUP: |
| case BUILT_IN_STRNDUP: |
| /* Unix98 specifies that errno is set on allocation failure. */ |
| if (flag_errno_math |
| && targetm.ref_may_alias_errno (ref)) |
| return true; |
| return false; |
| case BUILT_IN_STACK_SAVE: |
| case BUILT_IN_ALLOCA: |
| case BUILT_IN_ALLOCA_WITH_ALIGN: |
| case BUILT_IN_ASSUME_ALIGNED: |
| return false; |
| /* But posix_memalign stores a pointer into the memory pointed to |
| by its first argument. */ |
| case BUILT_IN_POSIX_MEMALIGN: |
| { |
| tree ptrptr = gimple_call_arg (call, 0); |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, ptrptr, |
| TYPE_SIZE_UNIT (ptr_type_node)); |
| return (refs_may_alias_p_1 (&dref, ref, false) |
| || (flag_errno_math |
| && targetm.ref_may_alias_errno (ref))); |
| } |
| /* Freeing memory kills the pointed-to memory. More importantly |
| the call has to serve as a barrier for moving loads and stores |
| across it. */ |
| case BUILT_IN_FREE: |
| case BUILT_IN_VA_END: |
| { |
| tree ptr = gimple_call_arg (call, 0); |
| return ptr_deref_may_alias_ref_p_1 (ptr, ref); |
| } |
| /* Realloc serves both as allocation point and deallocation point. */ |
| case BUILT_IN_REALLOC: |
| { |
| tree ptr = gimple_call_arg (call, 0); |
| /* Unix98 specifies that errno is set on allocation failure. */ |
| return ((flag_errno_math |
| && targetm.ref_may_alias_errno (ref)) |
| || ptr_deref_may_alias_ref_p_1 (ptr, ref)); |
| } |
| case BUILT_IN_GAMMA_R: |
| case BUILT_IN_GAMMAF_R: |
| case BUILT_IN_GAMMAL_R: |
| case BUILT_IN_LGAMMA_R: |
| case BUILT_IN_LGAMMAF_R: |
| case BUILT_IN_LGAMMAL_R: |
| { |
| tree out = gimple_call_arg (call, 1); |
| if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
| return true; |
| if (flag_errno_math) |
| break; |
| return false; |
| } |
| case BUILT_IN_FREXP: |
| case BUILT_IN_FREXPF: |
| case BUILT_IN_FREXPL: |
| case BUILT_IN_MODF: |
| case BUILT_IN_MODFF: |
| case BUILT_IN_MODFL: |
| { |
| tree out = gimple_call_arg (call, 1); |
| return ptr_deref_may_alias_ref_p_1 (out, ref); |
| } |
| case BUILT_IN_REMQUO: |
| case BUILT_IN_REMQUOF: |
| case BUILT_IN_REMQUOL: |
| { |
| tree out = gimple_call_arg (call, 2); |
| if (ptr_deref_may_alias_ref_p_1 (out, ref)) |
| return true; |
| if (flag_errno_math) |
| break; |
| return false; |
| } |
| case BUILT_IN_SINCOS: |
| case BUILT_IN_SINCOSF: |
| case BUILT_IN_SINCOSL: |
| { |
| tree sin = gimple_call_arg (call, 1); |
| tree cos = gimple_call_arg (call, 2); |
| return (ptr_deref_may_alias_ref_p_1 (sin, ref) |
| || ptr_deref_may_alias_ref_p_1 (cos, ref)); |
| } |
| /* __sync_* builtins and some OpenMP builtins act as threading |
| barriers. */ |
| #undef DEF_SYNC_BUILTIN |
| #define DEF_SYNC_BUILTIN(ENUM, NAME, TYPE, ATTRS) case ENUM: |
| #include "sync-builtins.def" |
| #undef DEF_SYNC_BUILTIN |
| case BUILT_IN_GOMP_ATOMIC_START: |
| case BUILT_IN_GOMP_ATOMIC_END: |
| case BUILT_IN_GOMP_BARRIER: |
| case BUILT_IN_GOMP_BARRIER_CANCEL: |
| case BUILT_IN_GOMP_TASKWAIT: |
| case BUILT_IN_GOMP_TASKGROUP_END: |
| case BUILT_IN_GOMP_CRITICAL_START: |
| case BUILT_IN_GOMP_CRITICAL_END: |
| case BUILT_IN_GOMP_CRITICAL_NAME_START: |
| case BUILT_IN_GOMP_CRITICAL_NAME_END: |
| case BUILT_IN_GOMP_LOOP_END: |
| case BUILT_IN_GOMP_LOOP_END_CANCEL: |
| case BUILT_IN_GOMP_ORDERED_START: |
| case BUILT_IN_GOMP_ORDERED_END: |
| case BUILT_IN_GOMP_SECTIONS_END: |
| case BUILT_IN_GOMP_SECTIONS_END_CANCEL: |
| case BUILT_IN_GOMP_SINGLE_COPY_START: |
| case BUILT_IN_GOMP_SINGLE_COPY_END: |
| return true; |
| default: |
| /* Fallthru to general call handling. */; |
| } |
| |
| /* Check if base is a global static variable that is not written |
| by the function. */ |
| if (callee != NULL_TREE && VAR_P (base) && TREE_STATIC (base)) |
| { |
| struct cgraph_node *node = cgraph_node::get (callee); |
| bitmap not_written; |
| |
| if (node |
| && (not_written = ipa_reference_get_not_written_global (node)) |
| && bitmap_bit_p (not_written, ipa_reference_var_uid (base))) |
| return false; |
| } |
| |
| /* Check if the base variable is call-clobbered. */ |
| if (DECL_P (base)) |
| return pt_solution_includes (gimple_call_clobber_set (call), base); |
| else if ((TREE_CODE (base) == MEM_REF |
| || TREE_CODE (base) == TARGET_MEM_REF) |
| && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME) |
| { |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)); |
| if (!pi) |
| return true; |
| |
| return pt_solutions_intersect (gimple_call_clobber_set (call), &pi->pt); |
| } |
| |
| return true; |
| } |
| |
| /* If the call in statement CALL may clobber the memory reference REF |
| return true, otherwise return false. */ |
| |
| bool |
| call_may_clobber_ref_p (gcall *call, tree ref) |
| { |
| bool res; |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| res = call_may_clobber_ref_p_1 (call, &r); |
| if (res) |
| ++alias_stats.call_may_clobber_ref_p_may_alias; |
| else |
| ++alias_stats.call_may_clobber_ref_p_no_alias; |
| return res; |
| } |
| |
| |
| /* If the statement STMT may clobber the memory reference REF return true, |
| otherwise return false. */ |
| |
| bool |
| stmt_may_clobber_ref_p_1 (gimple *stmt, ao_ref *ref) |
| { |
| if (is_gimple_call (stmt)) |
| { |
| tree lhs = gimple_call_lhs (stmt); |
| if (lhs |
| && TREE_CODE (lhs) != SSA_NAME) |
| { |
| ao_ref r; |
| ao_ref_init (&r, lhs); |
| if (refs_may_alias_p_1 (ref, &r, true)) |
| return true; |
| } |
| |
| return call_may_clobber_ref_p_1 (as_a <gcall *> (stmt), ref); |
| } |
| else if (gimple_assign_single_p (stmt)) |
| { |
| tree lhs = gimple_assign_lhs (stmt); |
| if (TREE_CODE (lhs) != SSA_NAME) |
| { |
| ao_ref r; |
| ao_ref_init (&r, lhs); |
| return refs_may_alias_p_1 (ref, &r, true); |
| } |
| } |
| else if (gimple_code (stmt) == GIMPLE_ASM) |
| return true; |
| |
| return false; |
| } |
| |
| bool |
| stmt_may_clobber_ref_p (gimple *stmt, tree ref) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return stmt_may_clobber_ref_p_1 (stmt, &r); |
| } |
| |
| /* Return true if store1 and store2 described by corresponding tuples |
| <BASE, OFFSET, SIZE, MAX_SIZE> have the same size and store to the same |
| address. */ |
| |
| static bool |
| same_addr_size_stores_p (tree base1, HOST_WIDE_INT offset1, HOST_WIDE_INT size1, |
| HOST_WIDE_INT max_size1, |
| tree base2, HOST_WIDE_INT offset2, HOST_WIDE_INT size2, |
| HOST_WIDE_INT max_size2) |
| { |
| /* Offsets need to be 0. */ |
| if (offset1 != 0 |
| || offset2 != 0) |
| return false; |
| |
| bool base1_obj_p = SSA_VAR_P (base1); |
| bool base2_obj_p = SSA_VAR_P (base2); |
| |
| /* We need one object. */ |
| if (base1_obj_p == base2_obj_p) |
| return false; |
| tree obj = base1_obj_p ? base1 : base2; |
| |
| /* And we need one MEM_REF. */ |
| bool base1_memref_p = TREE_CODE (base1) == MEM_REF; |
| bool base2_memref_p = TREE_CODE (base2) == MEM_REF; |
| if (base1_memref_p == base2_memref_p) |
| return false; |
| tree memref = base1_memref_p ? base1 : base2; |
| |
| /* Sizes need to be valid. */ |
| if (max_size1 == -1 || max_size2 == -1 |
| || size1 == -1 || size2 == -1) |
| return false; |
| |
| /* Max_size needs to match size. */ |
| if (max_size1 != size1 |
| || max_size2 != size2) |
| return false; |
| |
| /* Sizes need to match. */ |
| if (size1 != size2) |
| return false; |
| |
| |
| /* Check that memref is a store to pointer with singleton points-to info. */ |
| if (!integer_zerop (TREE_OPERAND (memref, 1))) |
| return false; |
| tree ptr = TREE_OPERAND (memref, 0); |
| if (TREE_CODE (ptr) != SSA_NAME) |
| return false; |
| struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr); |
| unsigned int pt_uid; |
| if (pi == NULL |
| || !pt_solution_singleton_or_null_p (&pi->pt, &pt_uid)) |
| return false; |
| |
| /* Be conservative with non-call exceptions when the address might |
| be NULL. */ |
| if (flag_non_call_exceptions && pi->pt.null) |
| return false; |
| |
| /* Check that ptr points relative to obj. */ |
| unsigned int obj_uid = DECL_PT_UID (obj); |
| if (obj_uid != pt_uid) |
| return false; |
| |
| /* Check that the object size is the same as the store size. That ensures us |
| that ptr points to the start of obj. */ |
| if (!tree_fits_shwi_p (DECL_SIZE (obj))) |
| return false; |
| HOST_WIDE_INT obj_size = tree_to_shwi (DECL_SIZE (obj)); |
| return obj_size == size1; |
| } |
| |
| /* If STMT kills the memory reference REF return true, otherwise |
| return false. */ |
| |
| bool |
| stmt_kills_ref_p (gimple *stmt, ao_ref *ref) |
| { |
| if (!ao_ref_base (ref)) |
| return false; |
| |
| if (gimple_has_lhs (stmt) |
| && TREE_CODE (gimple_get_lhs (stmt)) != SSA_NAME |
| /* The assignment is not necessarily carried out if it can throw |
| and we can catch it in the current function where we could inspect |
| the previous value. |
| ??? We only need to care about the RHS throwing. For aggregate |
| assignments or similar calls and non-call exceptions the LHS |
| might throw as well. */ |
| && !stmt_can_throw_internal (stmt)) |
| { |
| tree lhs = gimple_get_lhs (stmt); |
| /* If LHS is literally a base of the access we are done. */ |
| if (ref->ref) |
| { |
| tree base = ref->ref; |
| tree innermost_dropped_array_ref = NULL_TREE; |
| if (handled_component_p (base)) |
| { |
| tree saved_lhs0 = NULL_TREE; |
| if (handled_component_p (lhs)) |
| { |
| saved_lhs0 = TREE_OPERAND (lhs, 0); |
| TREE_OPERAND (lhs, 0) = integer_zero_node; |
| } |
| do |
| { |
| /* Just compare the outermost handled component, if |
| they are equal we have found a possible common |
| base. */ |
| tree saved_base0 = TREE_OPERAND (base, 0); |
| TREE_OPERAND (base, 0) = integer_zero_node; |
| bool res = operand_equal_p (lhs, base, 0); |
| TREE_OPERAND (base, 0) = saved_base0; |
| if (res) |
| break; |
| /* Remember if we drop an array-ref that we need to |
| double-check not being at struct end. */ |
| if (TREE_CODE (base) == ARRAY_REF |
| || TREE_CODE (base) == ARRAY_RANGE_REF) |
| innermost_dropped_array_ref = base; |
| /* Otherwise drop handled components of the access. */ |
| base = saved_base0; |
| } |
| while (handled_component_p (base)); |
| if (saved_lhs0) |
| TREE_OPERAND (lhs, 0) = saved_lhs0; |
| } |
| /* Finally check if the lhs has the same address and size as the |
| base candidate of the access. Watch out if we have dropped |
| an array-ref that was at struct end, this means ref->ref may |
| be outside of the TYPE_SIZE of its base. */ |
| if ((! innermost_dropped_array_ref |
| || ! array_at_struct_end_p (innermost_dropped_array_ref)) |
| && (lhs == base |
| || (((TYPE_SIZE (TREE_TYPE (lhs)) |
| == TYPE_SIZE (TREE_TYPE (base))) |
| || (TYPE_SIZE (TREE_TYPE (lhs)) |
| && TYPE_SIZE (TREE_TYPE (base)) |
| && operand_equal_p (TYPE_SIZE (TREE_TYPE (lhs)), |
| TYPE_SIZE (TREE_TYPE (base)), |
| 0))) |
| && operand_equal_p (lhs, base, |
| OEP_ADDRESS_OF |
| | OEP_MATCH_SIDE_EFFECTS)))) |
| return true; |
| } |
| |
| /* Now look for non-literal equal bases with the restriction of |
| handling constant offset and size. */ |
| /* For a must-alias check we need to be able to constrain |
| the access properly. */ |
| if (ref->max_size == -1) |
| return false; |
| HOST_WIDE_INT size, offset, max_size, ref_offset = ref->offset; |
| bool reverse; |
| tree base |
| = get_ref_base_and_extent (lhs, &offset, &size, &max_size, &reverse); |
| /* We can get MEM[symbol: sZ, index: D.8862_1] here, |
| so base == ref->base does not always hold. */ |
| if (base != ref->base) |
| { |
| /* Try using points-to info. */ |
| if (same_addr_size_stores_p (base, offset, size, max_size, ref->base, |
| ref->offset, ref->size, ref->max_size)) |
| return true; |
| |
| /* If both base and ref->base are MEM_REFs, only compare the |
| first operand, and if the second operand isn't equal constant, |
| try to add the offsets into offset and ref_offset. */ |
| if (TREE_CODE (base) == MEM_REF && TREE_CODE (ref->base) == MEM_REF |
| && TREE_OPERAND (base, 0) == TREE_OPERAND (ref->base, 0)) |
| { |
| if (!tree_int_cst_equal (TREE_OPERAND (base, 1), |
| TREE_OPERAND (ref->base, 1))) |
| { |
| offset_int off1 = mem_ref_offset (base); |
| off1 <<= LOG2_BITS_PER_UNIT; |
| off1 += offset; |
| offset_int off2 = mem_ref_offset (ref->base); |
| off2 <<= LOG2_BITS_PER_UNIT; |
| off2 += ref_offset; |
| if (wi::fits_shwi_p (off1) && wi::fits_shwi_p (off2)) |
| { |
| offset = off1.to_shwi (); |
| ref_offset = off2.to_shwi (); |
| } |
| else |
| size = -1; |
| } |
| } |
| else |
| size = -1; |
| } |
| /* For a must-alias check we need to be able to constrain |
| the access properly. */ |
| if (size != -1 && size == max_size) |
| { |
| if (offset <= ref_offset |
| && offset + size >= ref_offset + ref->max_size) |
| return true; |
| } |
| } |
| |
| if (is_gimple_call (stmt)) |
| { |
| tree callee = gimple_call_fndecl (stmt); |
| if (callee != NULL_TREE |
| && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL)) |
| switch (DECL_FUNCTION_CODE (callee)) |
| { |
| case BUILT_IN_FREE: |
| { |
| tree ptr = gimple_call_arg (stmt, 0); |
| tree base = ao_ref_base (ref); |
| if (base && TREE_CODE (base) == MEM_REF |
| && TREE_OPERAND (base, 0) == ptr) |
| return true; |
| break; |
| } |
| |
| case BUILT_IN_MEMCPY: |
| case BUILT_IN_MEMPCPY: |
| case BUILT_IN_MEMMOVE: |
| case BUILT_IN_MEMSET: |
| case BUILT_IN_MEMCPY_CHK: |
| case BUILT_IN_MEMPCPY_CHK: |
| case BUILT_IN_MEMMOVE_CHK: |
| case BUILT_IN_MEMSET_CHK: |
| { |
| /* For a must-alias check we need to be able to constrain |
| the access properly. */ |
| if (ref->max_size == -1) |
| return false; |
| tree dest = gimple_call_arg (stmt, 0); |
| tree len = gimple_call_arg (stmt, 2); |
| if (!tree_fits_shwi_p (len)) |
| return false; |
| tree rbase = ref->base; |
| offset_int roffset = ref->offset; |
| ao_ref dref; |
| ao_ref_init_from_ptr_and_size (&dref, dest, len); |
| tree base = ao_ref_base (&dref); |
| offset_int offset = dref.offset; |
| if (!base || dref.size == -1) |
| return false; |
| if (TREE_CODE (base) == MEM_REF) |
| { |
| if (TREE_CODE (rbase) != MEM_REF) |
| return false; |
| // Compare pointers. |
| offset += mem_ref_offset (base) << LOG2_BITS_PER_UNIT; |
| roffset += mem_ref_offset (rbase) << LOG2_BITS_PER_UNIT; |
| base = TREE_OPERAND (base, 0); |
| rbase = TREE_OPERAND (rbase, 0); |
| } |
| if (base == rbase |
| && offset <= roffset |
| && (roffset + ref->max_size |
| <= offset + (wi::to_offset (len) << LOG2_BITS_PER_UNIT))) |
| return true; |
| break; |
| } |
| |
| case BUILT_IN_VA_END: |
| { |
| tree ptr = gimple_call_arg (stmt, 0); |
| if (TREE_CODE (ptr) == ADDR_EXPR) |
| { |
| tree base = ao_ref_base (ref); |
| if (TREE_OPERAND (ptr, 0) == base) |
| return true; |
| } |
| break; |
| } |
| |
| default:; |
| } |
| } |
| return false; |
| } |
| |
| bool |
| stmt_kills_ref_p (gimple *stmt, tree ref) |
| { |
| ao_ref r; |
| ao_ref_init (&r, ref); |
| return stmt_kills_ref_p (stmt, &r); |
| } |
| |
| |
| /* Walk the virtual use-def chain of VUSE until hitting the virtual operand |
| TARGET or a statement clobbering the memory reference REF in which |
| case false is returned. The walk starts with VUSE, one argument of PHI. */ |
| |
| static bool |
| maybe_skip_until (gimple *phi, tree target, ao_ref *ref, |
| tree vuse, unsigned int *cnt, bitmap *visited, |
| bool abort_on_visited, |
| void *(*translate)(ao_ref *, tree, void *, bool *), |
| void *data) |
| { |
| basic_block bb = gimple_bb (phi); |
| |
| if (!*visited) |
| *visited = BITMAP_ALLOC (NULL); |
| |
| bitmap_set_bit (*visited, SSA_NAME_VERSION (PHI_RESULT (phi))); |
| |
| /* Walk until we hit the target. */ |
| while (vuse != target) |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (vuse); |
| /* Recurse for PHI nodes. */ |
| if (gimple_code (def_stmt) == GIMPLE_PHI) |
| { |
| /* An already visited PHI node ends the walk successfully. */ |
| if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt)))) |
| return !abort_on_visited; |
| vuse = get_continuation_for_phi (def_stmt, ref, cnt, |
| visited, abort_on_visited, |
| translate, data); |
| if (!vuse) |
| return false; |
| continue; |
| } |
| else if (gimple_nop_p (def_stmt)) |
| return false; |
| else |
| { |
| /* A clobbering statement or the end of the IL ends it failing. */ |
| ++*cnt; |
| if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| { |
| bool disambiguate_only = true; |
| if (translate |
| && (*translate) (ref, vuse, data, &disambiguate_only) == NULL) |
| ; |
| else |
| return false; |
| } |
| } |
| /* If we reach a new basic-block see if we already skipped it |
| in a previous walk that ended successfully. */ |
| if (gimple_bb (def_stmt) != bb) |
| { |
| if (!bitmap_set_bit (*visited, SSA_NAME_VERSION (vuse))) |
| return !abort_on_visited; |
| bb = gimple_bb (def_stmt); |
| } |
| vuse = gimple_vuse (def_stmt); |
| } |
| return true; |
| } |
| |
| /* For two PHI arguments ARG0 and ARG1 try to skip non-aliasing code |
| until we hit the phi argument definition that dominates the other one. |
| Return that, or NULL_TREE if there is no such definition. */ |
| |
| static tree |
| get_continuation_for_phi_1 (gimple *phi, tree arg0, tree arg1, |
| ao_ref *ref, unsigned int *cnt, |
| bitmap *visited, bool abort_on_visited, |
| void *(*translate)(ao_ref *, tree, void *, bool *), |
| void *data) |
| { |
| gimple *def0 = SSA_NAME_DEF_STMT (arg0); |
| gimple *def1 = SSA_NAME_DEF_STMT (arg1); |
| tree common_vuse; |
| |
| if (arg0 == arg1) |
| return arg0; |
| else if (gimple_nop_p (def0) |
| || (!gimple_nop_p (def1) |
| && dominated_by_p (CDI_DOMINATORS, |
| gimple_bb (def1), gimple_bb (def0)))) |
| { |
| if (maybe_skip_until (phi, arg0, ref, arg1, cnt, |
| visited, abort_on_visited, translate, data)) |
| return arg0; |
| } |
| else if (gimple_nop_p (def1) |
| || dominated_by_p (CDI_DOMINATORS, |
| gimple_bb (def0), gimple_bb (def1))) |
| { |
| if (maybe_skip_until (phi, arg1, ref, arg0, cnt, |
| visited, abort_on_visited, translate, data)) |
| return arg1; |
| } |
| /* Special case of a diamond: |
| MEM_1 = ... |
| goto (cond) ? L1 : L2 |
| L1: store1 = ... #MEM_2 = vuse(MEM_1) |
| goto L3 |
| L2: store2 = ... #MEM_3 = vuse(MEM_1) |
| L3: MEM_4 = PHI<MEM_2, MEM_3> |
| We were called with the PHI at L3, MEM_2 and MEM_3 don't |
| dominate each other, but still we can easily skip this PHI node |
| if we recognize that the vuse MEM operand is the same for both, |
| and that we can skip both statements (they don't clobber us). |
| This is still linear. Don't use maybe_skip_until, that might |
| potentially be slow. */ |
| else if ((common_vuse = gimple_vuse (def0)) |
| && common_vuse == gimple_vuse (def1)) |
| { |
| bool disambiguate_only = true; |
| *cnt += 2; |
| if ((!stmt_may_clobber_ref_p_1 (def0, ref) |
| || (translate |
| && (*translate) (ref, arg0, data, &disambiguate_only) == NULL)) |
| && (!stmt_may_clobber_ref_p_1 (def1, ref) |
| || (translate |
| && (*translate) (ref, arg1, data, &disambiguate_only) == NULL))) |
| return common_vuse; |
| } |
| |
| return NULL_TREE; |
| } |
| |
| |
| /* Starting from a PHI node for the virtual operand of the memory reference |
| REF find a continuation virtual operand that allows to continue walking |
| statements dominating PHI skipping only statements that cannot possibly |
| clobber REF. Increments *CNT for each alias disambiguation done. |
| Returns NULL_TREE if no suitable virtual operand can be found. */ |
| |
| tree |
| get_continuation_for_phi (gimple *phi, ao_ref *ref, |
| unsigned int *cnt, bitmap *visited, |
| bool abort_on_visited, |
| void *(*translate)(ao_ref *, tree, void *, bool *), |
| void *data) |
| { |
| unsigned nargs = gimple_phi_num_args (phi); |
| |
| /* Through a single-argument PHI we can simply look through. */ |
| if (nargs == 1) |
| return PHI_ARG_DEF (phi, 0); |
| |
| /* For two or more arguments try to pairwise skip non-aliasing code |
| until we hit the phi argument definition that dominates the other one. */ |
| else if (nargs >= 2) |
| { |
| tree arg0, arg1; |
| unsigned i; |
| |
| /* Find a candidate for the virtual operand which definition |
| dominates those of all others. */ |
| arg0 = PHI_ARG_DEF (phi, 0); |
| if (!SSA_NAME_IS_DEFAULT_DEF (arg0)) |
| for (i = 1; i < nargs; ++i) |
| { |
| arg1 = PHI_ARG_DEF (phi, i); |
| if (SSA_NAME_IS_DEFAULT_DEF (arg1)) |
| { |
| arg0 = arg1; |
| break; |
| } |
| if (dominated_by_p (CDI_DOMINATORS, |
| gimple_bb (SSA_NAME_DEF_STMT (arg0)), |
| gimple_bb (SSA_NAME_DEF_STMT (arg1)))) |
| arg0 = arg1; |
| } |
| |
| /* Then pairwise reduce against the found candidate. */ |
| for (i = 0; i < nargs; ++i) |
| { |
| arg1 = PHI_ARG_DEF (phi, i); |
| arg0 = get_continuation_for_phi_1 (phi, arg0, arg1, ref, |
| cnt, visited, abort_on_visited, |
| translate, data); |
| if (!arg0) |
| return NULL_TREE; |
| } |
| |
| return arg0; |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* Based on the memory reference REF and its virtual use VUSE call |
| WALKER for each virtual use that is equivalent to VUSE, including VUSE |
| itself. That is, for each virtual use for which its defining statement |
| does not clobber REF. |
| |
| WALKER is called with REF, the current virtual use and DATA. If |
| WALKER returns non-NULL the walk stops and its result is returned. |
| At the end of a non-successful walk NULL is returned. |
| |
| TRANSLATE if non-NULL is called with a pointer to REF, the virtual |
| use which definition is a statement that may clobber REF and DATA. |
| If TRANSLATE returns (void *)-1 the walk stops and NULL is returned. |
| If TRANSLATE returns non-NULL the walk stops and its result is returned. |
| If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed |
| to adjust REF and *DATA to make that valid. |
| |
| VALUEIZE if non-NULL is called with the next VUSE that is considered |
| and return value is substituted for that. This can be used to |
| implement optimistic value-numbering for example. Note that the |
| VUSE argument is assumed to be valueized already. |
| |
| TODO: Cache the vector of equivalent vuses per ref, vuse pair. */ |
| |
| void * |
| walk_non_aliased_vuses (ao_ref *ref, tree vuse, |
| void *(*walker)(ao_ref *, tree, unsigned int, void *), |
| void *(*translate)(ao_ref *, tree, void *, bool *), |
| tree (*valueize)(tree), |
| void *data) |
| { |
| bitmap visited = NULL; |
| void *res; |
| unsigned int cnt = 0; |
| bool translated = false; |
| |
| timevar_push (TV_ALIAS_STMT_WALK); |
| |
| do |
| { |
| gimple *def_stmt; |
| |
| /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
| res = (*walker) (ref, vuse, cnt, data); |
| /* Abort walk. */ |
| if (res == (void *)-1) |
| { |
| res = NULL; |
| break; |
| } |
| /* Lookup succeeded. */ |
| else if (res != NULL) |
| break; |
| |
| if (valueize) |
| vuse = valueize (vuse); |
| def_stmt = SSA_NAME_DEF_STMT (vuse); |
| if (gimple_nop_p (def_stmt)) |
| break; |
| else if (gimple_code (def_stmt) == GIMPLE_PHI) |
| vuse = get_continuation_for_phi (def_stmt, ref, &cnt, |
| &visited, translated, translate, data); |
| else |
| { |
| cnt++; |
| if (stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| { |
| if (!translate) |
| break; |
| bool disambiguate_only = false; |
| res = (*translate) (ref, vuse, data, &disambiguate_only); |
| /* Failed lookup and translation. */ |
| if (res == (void *)-1) |
| { |
| res = NULL; |
| break; |
| } |
| /* Lookup succeeded. */ |
| else if (res != NULL) |
| break; |
| /* Translation succeeded, continue walking. */ |
| translated = translated || !disambiguate_only; |
| } |
| vuse = gimple_vuse (def_stmt); |
| } |
| } |
| while (vuse); |
| |
| if (visited) |
| BITMAP_FREE (visited); |
| |
| timevar_pop (TV_ALIAS_STMT_WALK); |
| |
| return res; |
| } |
| |
| |
| /* Based on the memory reference REF call WALKER for each vdef which |
| defining statement may clobber REF, starting with VDEF. If REF |
| is NULL_TREE, each defining statement is visited. |
| |
| WALKER is called with REF, the current vdef and DATA. If WALKER |
| returns true the walk is stopped, otherwise it continues. |
| |
| If function entry is reached, FUNCTION_ENTRY_REACHED is set to true. |
| The pointer may be NULL and then we do not track this information. |
| |
| At PHI nodes walk_aliased_vdefs forks into one walk for reach |
| PHI argument (but only one walk continues on merge points), the |
| return value is true if any of the walks was successful. |
| |
| The function returns the number of statements walked or -1 if |
| LIMIT stmts were walked and the walk was aborted at this point. |
| If LIMIT is zero the walk is not aborted. */ |
| |
| static int |
| walk_aliased_vdefs_1 (ao_ref *ref, tree vdef, |
| bool (*walker)(ao_ref *, tree, void *), void *data, |
| bitmap *visited, unsigned int cnt, |
| bool *function_entry_reached, unsigned limit) |
| { |
| do |
| { |
| gimple *def_stmt = SSA_NAME_DEF_STMT (vdef); |
| |
| if (*visited |
| && !bitmap_set_bit (*visited, SSA_NAME_VERSION (vdef))) |
| return cnt; |
| |
| if (gimple_nop_p (def_stmt)) |
| { |
| if (function_entry_reached) |
| *function_entry_reached = true; |
| return cnt; |
| } |
| else if (gimple_code (def_stmt) == GIMPLE_PHI) |
| { |
| unsigned i; |
| if (!*visited) |
| *visited = BITMAP_ALLOC (NULL); |
| for (i = 0; i < gimple_phi_num_args (def_stmt); ++i) |
| { |
| int res = walk_aliased_vdefs_1 (ref, |
| gimple_phi_arg_def (def_stmt, i), |
| walker, data, visited, cnt, |
| function_entry_reached, limit); |
| if (res == -1) |
| return -1; |
| cnt = res; |
| } |
| return cnt; |
| } |
| |
| /* ??? Do we want to account this to TV_ALIAS_STMT_WALK? */ |
| cnt++; |
| if (cnt == limit) |
| return -1; |
| if ((!ref |
| || stmt_may_clobber_ref_p_1 (def_stmt, ref)) |
| && (*walker) (ref, vdef, data)) |
| return cnt; |
| |
| vdef = gimple_vuse (def_stmt); |
| } |
| while (1); |
| } |
| |
| int |
| walk_aliased_vdefs (ao_ref *ref, tree vdef, |
| bool (*walker)(ao_ref *, tree, void *), void *data, |
| bitmap *visited, |
| bool *function_entry_reached, unsigned int limit) |
| { |
| bitmap local_visited = NULL; |
| int ret; |
| |
| timevar_push (TV_ALIAS_STMT_WALK); |
| |
| if (function_entry_reached) |
| *function_entry_reached = false; |
| |
| ret = walk_aliased_vdefs_1 (ref, vdef, walker, data, |
| visited ? visited : &local_visited, 0, |
| function_entry_reached, limit); |
| if (local_visited) |
| BITMAP_FREE (local_visited); |
| |
| timevar_pop (TV_ALIAS_STMT_WALK); |
| |
| return ret; |
| } |
| |