| /* Language-level data type conversion for GNU C++. |
| Copyright (C) 1987, 88, 92, 93, 94, 95, 1996 Free Software Foundation, Inc. |
| Hacked by Michael Tiemann (tiemann@cygnus.com) |
| |
| This file is part of GNU CC. |
| |
| GNU CC 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 2, or (at your option) |
| any later version. |
| |
| GNU CC 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 GNU CC; see the file COPYING. If not, write to |
| the Free Software Foundation, 59 Temple Place - Suite 330, |
| Boston, MA 02111-1307, USA. */ |
| |
| |
| /* This file contains the functions for converting C expressions |
| to different data types. The only entry point is `convert'. |
| Every language front end must have a `convert' function |
| but what kind of conversions it does will depend on the language. */ |
| |
| #include "config.h" |
| #include "tree.h" |
| #include "flags.h" |
| #include "cp-tree.h" |
| #include "class.h" |
| #include "convert.h" |
| |
| extern tree static_aggregates; |
| |
| /* Change of width--truncation and extension of integers or reals-- |
| is represented with NOP_EXPR. Proper functioning of many things |
| assumes that no other conversions can be NOP_EXPRs. |
| |
| Conversion between integer and pointer is represented with CONVERT_EXPR. |
| Converting integer to real uses FLOAT_EXPR |
| and real to integer uses FIX_TRUNC_EXPR. |
| |
| Here is a list of all the functions that assume that widening and |
| narrowing is always done with a NOP_EXPR: |
| In convert.c, convert_to_integer. |
| In c-typeck.c, build_binary_op_nodefault (boolean ops), |
| and truthvalue_conversion. |
| In expr.c: expand_expr, for operands of a MULT_EXPR. |
| In fold-const.c: fold. |
| In tree.c: get_narrower and get_unwidened. |
| |
| C++: in multiple-inheritance, converting between pointers may involve |
| adjusting them by a delta stored within the class definition. */ |
| |
| /* Subroutines of `convert'. */ |
| |
| /* Build a thunk. What it is, is an entry point that when called will |
| adjust the this pointer (the first argument) by offset, and then |
| goto the real address of the function given by REAL_ADDR that we |
| would like called. What we return is the address of the thunk. */ |
| |
| static tree |
| build_thunk (offset, real_addr) |
| tree offset, real_addr; |
| { |
| if (TREE_CODE (real_addr) != ADDR_EXPR |
| || TREE_CODE (TREE_OPERAND (real_addr, 0)) != FUNCTION_DECL) |
| { |
| sorry ("MI pointer to member conversion too complex"); |
| return error_mark_node; |
| } |
| sorry ("MI pointer to member conversion too complex"); |
| return error_mark_node; |
| } |
| |
| /* Convert a `pointer to member' (POINTER_TYPE to METHOD_TYPE) into |
| another `pointer to method'. This may involved the creation of |
| a thunk to handle the this offset calculation. */ |
| |
| static tree |
| convert_fn_ptr (type, expr) |
| tree type, expr; |
| { |
| #if 0 /* We don't use thunks for pmfs. */ |
| if (flag_vtable_thunks) |
| { |
| tree intype = TREE_TYPE (expr); |
| tree binfo = get_binfo (TYPE_METHOD_BASETYPE (TREE_TYPE (intype)), |
| TYPE_METHOD_BASETYPE (TREE_TYPE (type)), 1); |
| if (binfo == error_mark_node) |
| { |
| error (" in pointer to member conversion"); |
| return error_mark_node; |
| } |
| if (binfo == NULL_TREE) |
| { |
| /* ARM 4.8 restriction. */ |
| error ("invalid pointer to member conversion"); |
| return error_mark_node; |
| } |
| |
| if (BINFO_OFFSET_ZEROP (binfo)) |
| return build1 (NOP_EXPR, type, expr); |
| return build1 (NOP_EXPR, type, build_thunk (BINFO_OFFSET (binfo), expr)); |
| } |
| else |
| #endif |
| return build_ptrmemfunc (type, expr, 1); |
| } |
| |
| /* if converting pointer to pointer |
| if dealing with classes, check for derived->base or vice versa |
| else if dealing with method pointers, delegate |
| else convert blindly |
| else if converting class, pass off to build_type_conversion |
| else try C-style pointer conversion */ |
| |
| static tree |
| cp_convert_to_pointer (type, expr) |
| tree type, expr; |
| { |
| register tree intype = TREE_TYPE (expr); |
| register enum tree_code form; |
| |
| if (IS_AGGR_TYPE (intype)) |
| { |
| tree rval; |
| |
| intype = complete_type (intype); |
| if (TYPE_SIZE (intype) == NULL_TREE) |
| { |
| cp_error ("can't convert from incomplete type `%T' to `%T'", |
| intype, type); |
| return error_mark_node; |
| } |
| |
| rval = build_type_conversion (CONVERT_EXPR, type, expr, 1); |
| if (rval) |
| { |
| if (rval == error_mark_node) |
| cp_error ("conversion of `%E' from `%T' to `%T' is ambiguous", |
| expr, intype, type); |
| return rval; |
| } |
| } |
| |
| if (TYPE_PTRMEMFUNC_P (type)) |
| type = TYPE_PTRMEMFUNC_FN_TYPE (type); |
| |
| /* Handle anachronistic conversions from (::*)() to cv void* or (*)(). */ |
| if (TREE_CODE (type) == POINTER_TYPE |
| && (TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE |
| || TYPE_MAIN_VARIANT (TREE_TYPE (type)) == void_type_node)) |
| { |
| /* Allow an implicit this pointer for pointer to member |
| functions. */ |
| if (TYPE_PTRMEMFUNC_P (intype)) |
| { |
| tree decl, basebinfo; |
| tree fntype = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (intype)); |
| tree t = TYPE_METHOD_BASETYPE (fntype); |
| |
| if (current_class_type == 0 |
| || get_base_distance (t, current_class_type, 0, &basebinfo) |
| == -1) |
| { |
| decl = build1 (NOP_EXPR, t, error_mark_node); |
| } |
| else if (current_class_ptr == 0) |
| decl = build1 (NOP_EXPR, t, error_mark_node); |
| else |
| decl = current_class_ref; |
| |
| expr = build (OFFSET_REF, fntype, decl, expr); |
| } |
| |
| if (TREE_CODE (expr) == OFFSET_REF |
| && TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) |
| expr = resolve_offset_ref (expr); |
| if (TREE_CODE (TREE_TYPE (expr)) == METHOD_TYPE) |
| expr = build_addr_func (expr); |
| if (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE) |
| { |
| if (TREE_CODE (TREE_TYPE (TREE_TYPE (expr))) == METHOD_TYPE) |
| if (pedantic || warn_pmf2ptr) |
| cp_pedwarn ("converting from `%T' to `%T'", TREE_TYPE (expr), |
| type); |
| return build1 (NOP_EXPR, type, expr); |
| } |
| intype = TREE_TYPE (expr); |
| } |
| |
| if (TYPE_PTRMEMFUNC_P (intype)) |
| intype = TYPE_PTRMEMFUNC_FN_TYPE (intype); |
| |
| form = TREE_CODE (intype); |
| |
| if (form == POINTER_TYPE || form == REFERENCE_TYPE) |
| { |
| intype = TYPE_MAIN_VARIANT (intype); |
| |
| if (TYPE_MAIN_VARIANT (type) != intype |
| && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
| && IS_AGGR_TYPE (TREE_TYPE (type)) |
| && IS_AGGR_TYPE (TREE_TYPE (intype)) |
| && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
| { |
| enum tree_code code = PLUS_EXPR; |
| tree binfo = get_binfo (TREE_TYPE (type), TREE_TYPE (intype), 1); |
| if (binfo == error_mark_node) |
| return error_mark_node; |
| if (binfo == NULL_TREE) |
| { |
| binfo = get_binfo (TREE_TYPE (intype), TREE_TYPE (type), 1); |
| if (binfo == error_mark_node) |
| return error_mark_node; |
| code = MINUS_EXPR; |
| } |
| if (binfo) |
| { |
| if (TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (type)) |
| || TYPE_USES_VIRTUAL_BASECLASSES (TREE_TYPE (intype)) |
| || ! BINFO_OFFSET_ZEROP (binfo)) |
| { |
| /* Need to get the path we took. */ |
| tree path; |
| |
| if (code == PLUS_EXPR) |
| get_base_distance (TREE_TYPE (type), TREE_TYPE (intype), 0, &path); |
| else |
| get_base_distance (TREE_TYPE (intype), TREE_TYPE (type), 0, &path); |
| return build_vbase_path (code, type, expr, path, 0); |
| } |
| } |
| } |
| if (TREE_CODE (TREE_TYPE (intype)) == METHOD_TYPE |
| && TREE_CODE (type) == POINTER_TYPE |
| && TREE_CODE (TREE_TYPE (type)) == METHOD_TYPE) |
| return convert_fn_ptr (type, expr); |
| |
| if (TREE_CODE (TREE_TYPE (type)) == OFFSET_TYPE |
| && TREE_CODE (TREE_TYPE (intype)) == OFFSET_TYPE) |
| { |
| tree b1 = TYPE_OFFSET_BASETYPE (TREE_TYPE (type)); |
| tree b2 = TYPE_OFFSET_BASETYPE (TREE_TYPE (intype)); |
| tree binfo = get_binfo (b1, b2, 1); |
| if (binfo == NULL_TREE) |
| binfo = get_binfo (b2, b1, 1); |
| if (binfo == error_mark_node) |
| return error_mark_node; |
| } |
| |
| if (TREE_CODE (TREE_TYPE (intype)) == METHOD_TYPE |
| || (TREE_CODE (type) == POINTER_TYPE |
| && TREE_CODE (TREE_TYPE (type)) == METHOD_TYPE)) |
| { |
| cp_error ("cannot convert `%E' from type `%T' to type `%T'", |
| expr, intype, type); |
| return error_mark_node; |
| } |
| |
| return build1 (NOP_EXPR, type, expr); |
| } |
| |
| my_friendly_assert (form != OFFSET_TYPE, 186); |
| |
| if (TYPE_LANG_SPECIFIC (intype) |
| && (IS_SIGNATURE_POINTER (intype) || IS_SIGNATURE_REFERENCE (intype))) |
| return convert_to_pointer (type, build_optr_ref (expr)); |
| |
| if (integer_zerop (expr)) |
| { |
| if (TREE_CODE (TREE_TYPE (type)) == METHOD_TYPE) |
| return build_ptrmemfunc (type, expr, 0); |
| expr = build_int_2 (0, 0); |
| TREE_TYPE (expr) = type; |
| return expr; |
| } |
| |
| if (INTEGRAL_CODE_P (form)) |
| { |
| if (type_precision (intype) == POINTER_SIZE) |
| return build1 (CONVERT_EXPR, type, expr); |
| expr = cp_convert (type_for_size (POINTER_SIZE, 0), expr); |
| /* Modes may be different but sizes should be the same. */ |
| if (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (expr))) |
| != GET_MODE_SIZE (TYPE_MODE (type))) |
| /* There is supposed to be some integral type |
| that is the same width as a pointer. */ |
| abort (); |
| return convert_to_pointer (type, expr); |
| } |
| |
| cp_error ("cannot convert `%E' from type `%T' to type `%T'", |
| expr, intype, type); |
| return error_mark_node; |
| } |
| |
| /* Like convert, except permit conversions to take place which |
| are not normally allowed due to access restrictions |
| (such as conversion from sub-type to private super-type). */ |
| |
| static tree |
| convert_to_pointer_force (type, expr) |
| tree type, expr; |
| { |
| register tree intype = TREE_TYPE (expr); |
| register enum tree_code form = TREE_CODE (intype); |
| |
| if (integer_zerop (expr)) |
| { |
| expr = build_int_2 (0, 0); |
| TREE_TYPE (expr) = type; |
| return expr; |
| } |
| |
| /* Convert signature pointer/reference to `void *' first. */ |
| if (form == RECORD_TYPE |
| && (IS_SIGNATURE_POINTER (intype) || IS_SIGNATURE_REFERENCE (intype))) |
| { |
| expr = build_optr_ref (expr); |
| intype = TREE_TYPE (expr); |
| form = TREE_CODE (intype); |
| } |
| |
| if (form == POINTER_TYPE) |
| { |
| intype = TYPE_MAIN_VARIANT (intype); |
| |
| if (TYPE_MAIN_VARIANT (type) != intype |
| && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE |
| && IS_AGGR_TYPE (TREE_TYPE (type)) |
| && IS_AGGR_TYPE (TREE_TYPE (intype)) |
| && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE) |
| { |
| enum tree_code code = PLUS_EXPR; |
| tree path; |
| int distance = get_base_distance (TREE_TYPE (type), |
| TREE_TYPE (intype), 0, &path); |
| if (distance == -2) |
| { |
| ambig: |
| cp_error ("type `%T' is ambiguous baseclass of `%s'", |
| TREE_TYPE (type), |
| TYPE_NAME_STRING (TREE_TYPE (intype))); |
| return error_mark_node; |
| } |
| if (distance == -1) |
| { |
| distance = get_base_distance (TREE_TYPE (intype), |
| TREE_TYPE (type), 0, &path); |
| if (distance == -2) |
| goto ambig; |
| if (distance < 0) |
| /* Doesn't need any special help from us. */ |
| return build1 (NOP_EXPR, type, expr); |
| |
| code = MINUS_EXPR; |
| } |
| return build_vbase_path (code, type, expr, path, 0); |
| } |
| } |
| |
| return cp_convert_to_pointer (type, expr); |
| } |
| |
| /* We are passing something to a function which requires a reference. |
| The type we are interested in is in TYPE. The initial |
| value we have to begin with is in ARG. |
| |
| FLAGS controls how we manage access checking. |
| DIRECT_BIND in FLAGS controls how any temporaries are generated. */ |
| |
| static tree |
| build_up_reference (type, arg, flags, checkconst) |
| tree type, arg; |
| int flags, checkconst; |
| { |
| tree rval; |
| tree argtype = TREE_TYPE (arg); |
| tree target_type = TREE_TYPE (type); |
| |
| my_friendly_assert (TREE_CODE (type) == REFERENCE_TYPE, 187); |
| |
| if ((flags & DIRECT_BIND) && ! real_lvalue_p (arg)) |
| { |
| tree targ = arg; |
| if (toplevel_bindings_p ()) |
| arg = get_temp_name (argtype, 1); |
| else |
| { |
| arg = pushdecl (build_decl (VAR_DECL, NULL_TREE, argtype)); |
| DECL_ARTIFICIAL (arg) = 1; |
| } |
| DECL_INITIAL (arg) = targ; |
| cp_finish_decl (arg, targ, NULL_TREE, 0, LOOKUP_ONLYCONVERTING); |
| } |
| else if (!(flags & DIRECT_BIND) && ! lvalue_p (arg)) |
| { |
| tree slot = build_decl (VAR_DECL, NULL_TREE, argtype); |
| arg = build (TARGET_EXPR, argtype, slot, arg, NULL_TREE, NULL_TREE); |
| } |
| |
| /* If we had a way to wrap this up, and say, if we ever needed it's |
| address, transform all occurrences of the register, into a memory |
| reference we could win better. */ |
| rval = build_unary_op (ADDR_EXPR, arg, 1); |
| if ((flags & LOOKUP_PROTECT) |
| && TYPE_MAIN_VARIANT (argtype) != TYPE_MAIN_VARIANT (target_type) |
| && IS_AGGR_TYPE (argtype) |
| && IS_AGGR_TYPE (target_type)) |
| { |
| /* We go through get_binfo for the access control. */ |
| tree binfo = get_binfo (target_type, argtype, 1); |
| if (binfo == error_mark_node) |
| return error_mark_node; |
| if (binfo == NULL_TREE) |
| return error_not_base_type (target_type, argtype); |
| rval = convert_pointer_to_real (binfo, rval); |
| } |
| else |
| rval |
| = convert_to_pointer_force (build_pointer_type (target_type), rval); |
| rval = build1 (NOP_EXPR, type, rval); |
| TREE_CONSTANT (rval) = TREE_CONSTANT (TREE_OPERAND (rval, 0)); |
| return rval; |
| } |
| |
| /* For C++: Only need to do one-level references, but cannot |
| get tripped up on signed/unsigned differences. |
| |
| DECL is either NULL_TREE or the _DECL node for a reference that is being |
| initialized. It can be error_mark_node if we don't know the _DECL but |
| we know it's an initialization. */ |
| |
| tree |
| convert_to_reference (reftype, expr, convtype, flags, decl) |
| tree reftype, expr; |
| int convtype, flags; |
| tree decl; |
| { |
| register tree type = TYPE_MAIN_VARIANT (TREE_TYPE (reftype)); |
| register tree intype = TREE_TYPE (expr); |
| tree rval = NULL_TREE; |
| tree rval_as_conversion = NULL_TREE; |
| int i; |
| |
| if (TREE_CODE (intype) == REFERENCE_TYPE) |
| my_friendly_abort (364); |
| |
| intype = TYPE_MAIN_VARIANT (intype); |
| |
| i = comp_target_types (type, intype, 0); |
| |
| if (i <= 0 && (convtype & CONV_IMPLICIT) && IS_AGGR_TYPE (intype) |
| && ! (flags & LOOKUP_NO_CONVERSION)) |
| { |
| /* Look for a user-defined conversion to lvalue that we can use. */ |
| |
| if (flag_ansi_overloading) |
| rval_as_conversion |
| = build_type_conversion (CONVERT_EXPR, reftype, expr, 1); |
| else |
| rval_as_conversion = build_type_conversion (CONVERT_EXPR, type, expr, 1); |
| |
| if (rval_as_conversion && rval_as_conversion != error_mark_node |
| && real_lvalue_p (rval_as_conversion)) |
| { |
| expr = rval_as_conversion; |
| rval_as_conversion = NULL_TREE; |
| intype = type; |
| i = 1; |
| } |
| } |
| |
| if (((convtype & CONV_STATIC) && i == -1) |
| || ((convtype & CONV_IMPLICIT) && i == 1)) |
| { |
| if (flags & LOOKUP_COMPLAIN) |
| { |
| tree ttl = TREE_TYPE (reftype); |
| tree ttr; |
| |
| { |
| int r = TREE_READONLY (expr); |
| int v = TREE_THIS_VOLATILE (expr); |
| ttr = cp_build_type_variant (TREE_TYPE (expr), r, v); |
| } |
| |
| if (! real_lvalue_p (expr) && ! TYPE_READONLY (ttl)) |
| { |
| if (decl) |
| /* Ensure semantics of [dcl.init.ref] */ |
| cp_pedwarn ("initialization of non-const reference `%#T' from rvalue `%T'", |
| reftype, intype); |
| else |
| cp_pedwarn ("conversion to non-const `%T' from rvalue `%T'", |
| reftype, intype); |
| } |
| else if (! (convtype & CONV_CONST)) |
| { |
| if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr)) |
| cp_pedwarn ("conversion from `%T' to `%T' discards const", |
| ttr, reftype); |
| else if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr)) |
| cp_pedwarn ("conversion from `%T' to `%T' discards volatile", |
| ttr, reftype); |
| } |
| } |
| |
| return build_up_reference (reftype, expr, flags, |
| ! (convtype & CONV_CONST)); |
| } |
| else if ((convtype & CONV_REINTERPRET) && lvalue_p (expr)) |
| { |
| /* When casting an lvalue to a reference type, just convert into |
| a pointer to the new type and deference it. This is allowed |
| by San Diego WP section 5.2.9 paragraph 12, though perhaps it |
| should be done directly (jason). (int &)ri ---> *(int*)&ri */ |
| |
| /* B* bp; A& ar = (A&)bp; is valid, but it's probably not what they |
| meant. */ |
| if (TREE_CODE (intype) == POINTER_TYPE |
| && (comptypes (TREE_TYPE (intype), type, -1))) |
| cp_warning ("casting `%T' to `%T' does not dereference pointer", |
| intype, reftype); |
| |
| rval = build_unary_op (ADDR_EXPR, expr, 0); |
| if (rval != error_mark_node) |
| rval = convert_force (build_pointer_type (TREE_TYPE (reftype)), rval, 0); |
| if (rval != error_mark_node) |
| rval = build1 (NOP_EXPR, reftype, rval); |
| } |
| else if (flag_ansi_overloading) |
| { |
| rval = convert_for_initialization (NULL_TREE, type, expr, flags, |
| "converting", 0, 0); |
| if (rval == error_mark_node) |
| return error_mark_node; |
| rval = build_up_reference (reftype, rval, flags, 1); |
| |
| if (rval && ! TYPE_READONLY (TREE_TYPE (reftype))) |
| cp_pedwarn ("initializing non-const `%T' with `%T' will use a temporary", |
| reftype, intype); |
| } |
| else |
| { |
| tree rval_as_ctor = NULL_TREE; |
| |
| if (rval_as_conversion) |
| { |
| if (rval_as_conversion == error_mark_node) |
| { |
| cp_error ("conversion from `%T' to `%T' is ambiguous", |
| intype, reftype); |
| return error_mark_node; |
| } |
| rval_as_conversion = build_up_reference (reftype, rval_as_conversion, |
| flags, 1); |
| } |
| |
| /* Definitely need to go through a constructor here. */ |
| if (TYPE_HAS_CONSTRUCTOR (type) |
| && ! CLASSTYPE_ABSTRACT_VIRTUALS (type) |
| && (rval = build_method_call |
| (NULL_TREE, ctor_identifier, |
| build_tree_list (NULL_TREE, expr), TYPE_BINFO (type), |
| LOOKUP_NO_CONVERSION|LOOKUP_SPECULATIVELY |
| | LOOKUP_ONLYCONVERTING))) |
| { |
| tree init; |
| |
| if (toplevel_bindings_p ()) |
| { |
| tree t = get_temp_name (type, toplevel_bindings_p ()); |
| init = build_method_call (t, ctor_identifier, |
| build_tree_list (NULL_TREE, expr), |
| TYPE_BINFO (type), |
| LOOKUP_NORMAL|LOOKUP_NO_CONVERSION |
| | LOOKUP_ONLYCONVERTING); |
| |
| if (init == error_mark_node) |
| return error_mark_node; |
| |
| make_decl_rtl (t, NULL_PTR, 1); |
| static_aggregates = perm_tree_cons (expr, t, static_aggregates); |
| rval = build_unary_op (ADDR_EXPR, t, 0); |
| } |
| else |
| { |
| init = build_method_call (NULL_TREE, ctor_identifier, |
| build_tree_list (NULL_TREE, expr), |
| TYPE_BINFO (type), |
| LOOKUP_NORMAL|LOOKUP_NO_CONVERSION |
| |LOOKUP_ONLYCONVERTING); |
| |
| if (init == error_mark_node) |
| return error_mark_node; |
| |
| rval = build_cplus_new (type, init); |
| rval = build_up_reference (reftype, rval, flags, 1); |
| } |
| rval_as_ctor = rval; |
| } |
| |
| if (rval_as_ctor && rval_as_conversion) |
| { |
| cp_error ("ambiguous conversion from `%T' to `%T'; both user-defined conversion and constructor apply", |
| intype, reftype); |
| return error_mark_node; |
| } |
| else if (rval_as_ctor) |
| rval = rval_as_ctor; |
| else if (rval_as_conversion) |
| rval = rval_as_conversion; |
| else if (! IS_AGGR_TYPE (type) && ! IS_AGGR_TYPE (intype)) |
| { |
| rval = cp_convert (type, expr); |
| if (rval == error_mark_node) |
| return error_mark_node; |
| |
| rval = build_up_reference (reftype, rval, flags, 1); |
| } |
| |
| if (rval && ! TYPE_READONLY (TREE_TYPE (reftype))) |
| cp_pedwarn ("initializing non-const `%T' with `%T' will use a temporary", |
| reftype, intype); |
| } |
| |
| if (rval) |
| { |
| /* If we found a way to convert earlier, then use it. */ |
| return rval; |
| } |
| |
| my_friendly_assert (TREE_CODE (intype) != OFFSET_TYPE, 189); |
| |
| if (flags & LOOKUP_COMPLAIN) |
| cp_error ("cannot convert type `%T' to type `%T'", intype, reftype); |
| |
| if (flags & LOOKUP_SPECULATIVELY) |
| return NULL_TREE; |
| |
| return error_mark_node; |
| } |
| |
| /* We are using a reference VAL for its value. Bash that reference all the |
| way down to its lowest form. */ |
| |
| tree |
| convert_from_reference (val) |
| tree val; |
| { |
| tree type = TREE_TYPE (val); |
| |
| if (TREE_CODE (type) == OFFSET_TYPE) |
| type = TREE_TYPE (type); |
| if (TREE_CODE (type) == REFERENCE_TYPE) |
| return build_indirect_ref (val, NULL_PTR); |
| return val; |
| } |
| |
| /* See if there is a constructor of type TYPE which will convert |
| EXPR. The reference manual seems to suggest (8.5.6) that we need |
| not worry about finding constructors for base classes, then converting |
| to the derived class. |
| |
| MSGP is a pointer to a message that would be an appropriate error |
| string. If MSGP is NULL, then we are not interested in reporting |
| errors. */ |
| |
| tree |
| convert_to_aggr (type, expr, msgp, protect) |
| tree type, expr; |
| char **msgp; |
| int protect; |
| { |
| tree basetype = type; |
| tree name = TYPE_IDENTIFIER (basetype); |
| tree function, fndecl, fntype, parmtypes, parmlist, result; |
| #if 0 |
| /* See code below that used this. */ |
| tree method_name; |
| #endif |
| tree access; |
| int can_be_private, can_be_protected; |
| |
| if (! TYPE_HAS_CONSTRUCTOR (basetype)) |
| { |
| if (msgp) |
| *msgp = "type `%s' does not have a constructor"; |
| return error_mark_node; |
| } |
| |
| access = access_public_node; |
| can_be_private = 0; |
| can_be_protected = IDENTIFIER_CLASS_VALUE (name) || name == current_class_name; |
| |
| parmlist = build_tree_list (NULL_TREE, expr); |
| parmtypes = tree_cons (NULL_TREE, TREE_TYPE (expr), void_list_node); |
| |
| if (TYPE_USES_VIRTUAL_BASECLASSES (basetype)) |
| { |
| parmtypes = tree_cons (NULL_TREE, integer_type_node, parmtypes); |
| parmlist = tree_cons (NULL_TREE, integer_one_node, parmlist); |
| } |
| |
| /* The type of the first argument will be filled in inside the loop. */ |
| parmlist = tree_cons (NULL_TREE, integer_zero_node, parmlist); |
| parmtypes = tree_cons (NULL_TREE, build_pointer_type (basetype), parmtypes); |
| |
| /* No exact conversion was found. See if an approximate |
| one will do. */ |
| fndecl = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (basetype), 0); |
| |
| { |
| int saw_private = 0; |
| int saw_protected = 0; |
| struct candidate *candidates |
| = (struct candidate *) alloca ((decl_list_length (fndecl)+1) * sizeof (struct candidate)); |
| struct candidate *cp = candidates; |
| |
| while (fndecl) |
| { |
| function = fndecl; |
| cp->h_len = 2; |
| cp->harshness = (struct harshness_code *) |
| alloca (3 * sizeof (struct harshness_code)); |
| |
| compute_conversion_costs (fndecl, parmlist, cp, 2); |
| if ((cp->h.code & EVIL_CODE) == 0) |
| { |
| cp->u.field = fndecl; |
| if (protect) |
| { |
| if (TREE_PRIVATE (fndecl)) |
| access = access_private_node; |
| else if (TREE_PROTECTED (fndecl)) |
| access = access_protected_node; |
| else |
| access = access_public_node; |
| } |
| else |
| access = access_public_node; |
| |
| if (access == access_private_node |
| ? (basetype == current_class_type |
| || is_friend (basetype, cp->function) |
| || purpose_member (basetype, DECL_ACCESS (fndecl))) |
| : access == access_protected_node |
| ? (can_be_protected |
| || purpose_member (basetype, DECL_ACCESS (fndecl))) |
| : 1) |
| { |
| if (cp->h.code <= TRIVIAL_CODE) |
| goto found_and_ok; |
| cp++; |
| } |
| else |
| { |
| if (access == access_private_node) |
| saw_private = 1; |
| else |
| saw_protected = 1; |
| } |
| } |
| fndecl = DECL_CHAIN (fndecl); |
| } |
| if (cp - candidates) |
| { |
| /* Rank from worst to best. Then cp will point to best one. |
| Private fields have their bits flipped. For unsigned |
| numbers, this should make them look very large. |
| If the best alternate has a (signed) negative value, |
| then all we ever saw were private members. */ |
| if (cp - candidates > 1) |
| qsort (candidates, /* char *base */ |
| cp - candidates, /* int nel */ |
| sizeof (struct candidate), /* int width */ |
| rank_for_overload); /* int (*compar)() */ |
| |
| --cp; |
| if (cp->h.code & EVIL_CODE) |
| { |
| if (msgp) |
| *msgp = "ambiguous type conversion possible for `%s'"; |
| return error_mark_node; |
| } |
| |
| function = cp->function; |
| fndecl = cp->u.field; |
| goto found_and_ok; |
| } |
| else if (msgp) |
| { |
| if (saw_private) |
| if (saw_protected) |
| *msgp = "only private and protected conversions apply"; |
| else |
| *msgp = "only private conversions apply"; |
| else if (saw_protected) |
| *msgp = "only protected conversions apply"; |
| else |
| *msgp = "no appropriate conversion to type `%s'"; |
| } |
| return error_mark_node; |
| } |
| /* NOTREACHED */ |
| |
| found: |
| if (access == access_private_node) |
| if (! can_be_private) |
| { |
| if (msgp) |
| *msgp = TREE_PRIVATE (fndecl) |
| ? "conversion to type `%s' is private" |
| : "conversion to type `%s' is from private base class"; |
| return error_mark_node; |
| } |
| if (access == access_protected_node) |
| if (! can_be_protected) |
| { |
| if (msgp) |
| *msgp = TREE_PRIVATE (fndecl) |
| ? "conversion to type `%s' is protected" |
| : "conversion to type `%s' is from protected base class"; |
| return error_mark_node; |
| } |
| function = fndecl; |
| found_and_ok: |
| |
| /* It will convert, but we don't do anything about it yet. */ |
| if (msgp == 0) |
| return NULL_TREE; |
| |
| fntype = TREE_TYPE (function); |
| |
| parmlist = convert_arguments (NULL_TREE, TYPE_ARG_TYPES (fntype), |
| parmlist, NULL_TREE, LOOKUP_NORMAL); |
| |
| result = build_call (function, TREE_TYPE (fntype), parmlist); |
| return result; |
| } |
| |
| /* Call this when we know (for any reason) that expr is not, in fact, |
| zero. This routine is like convert_pointer_to, but it pays |
| attention to which specific instance of what type we want to |
| convert to. This routine should eventually become |
| convert_to_pointer after all references to convert_to_pointer |
| are removed. */ |
| |
| tree |
| convert_pointer_to_real (binfo, expr) |
| tree binfo, expr; |
| { |
| register tree intype = TREE_TYPE (expr); |
| tree ptr_type; |
| tree type, rval; |
| |
| if (TREE_CODE (binfo) == TREE_VEC) |
| type = BINFO_TYPE (binfo); |
| else if (IS_AGGR_TYPE (binfo)) |
| { |
| type = binfo; |
| } |
| else |
| { |
| type = binfo; |
| binfo = NULL_TREE; |
| } |
| |
| ptr_type = cp_build_type_variant (type, TYPE_READONLY (TREE_TYPE (intype)), |
| TYPE_VOLATILE (TREE_TYPE (intype))); |
| ptr_type = build_pointer_type (ptr_type); |
| if (ptr_type == TYPE_MAIN_VARIANT (intype)) |
| return expr; |
| |
| if (intype == error_mark_node) |
| return error_mark_node; |
| |
| my_friendly_assert (!integer_zerop (expr), 191); |
| |
| if (TREE_CODE (type) == RECORD_TYPE |
| && TREE_CODE (TREE_TYPE (intype)) == RECORD_TYPE |
| && type != TYPE_MAIN_VARIANT (TREE_TYPE (intype))) |
| { |
| tree path; |
| int distance |
| = get_base_distance (binfo, TYPE_MAIN_VARIANT (TREE_TYPE (intype)), |
| 0, &path); |
| |
| /* This function shouldn't be called with unqualified arguments |
| but if it is, give them an error message that they can read. */ |
| if (distance < 0) |
| { |
| cp_error ("cannot convert a pointer of type `%T' to a pointer of type `%T'", |
| TREE_TYPE (intype), type); |
| |
| if (distance == -2) |
| cp_error ("because `%T' is an ambiguous base class", type); |
| return error_mark_node; |
| } |
| |
| return build_vbase_path (PLUS_EXPR, ptr_type, expr, path, 1); |
| } |
| rval = build1 (NOP_EXPR, ptr_type, |
| TREE_CODE (expr) == NOP_EXPR ? TREE_OPERAND (expr, 0) : expr); |
| TREE_CONSTANT (rval) = TREE_CONSTANT (expr); |
| return rval; |
| } |
| |
| /* Call this when we know (for any reason) that expr is |
| not, in fact, zero. This routine gets a type out of the first |
| argument and uses it to search for the type to convert to. If there |
| is more than one instance of that type in the expr, the conversion is |
| ambiguous. This routine should eventually go away, and all |
| callers should use convert_to_pointer_real. */ |
| |
| tree |
| convert_pointer_to (binfo, expr) |
| tree binfo, expr; |
| { |
| tree type; |
| |
| if (TREE_CODE (binfo) == TREE_VEC) |
| type = BINFO_TYPE (binfo); |
| else if (IS_AGGR_TYPE (binfo)) |
| type = binfo; |
| else |
| type = binfo; |
| return convert_pointer_to_real (type, expr); |
| } |
| |
| /* C++ conversions, preference to static cast conversions. */ |
| |
| tree |
| cp_convert (type, expr) |
| tree type, expr; |
| { |
| return ocp_convert (type, expr, CONV_OLD_CONVERT, LOOKUP_NORMAL); |
| } |
| |
| /* Conversion... |
| |
| FLAGS indicates how we should behave. */ |
| |
| tree |
| ocp_convert (type, expr, convtype, flags) |
| tree type, expr; |
| int convtype, flags; |
| { |
| register tree e = expr; |
| register enum tree_code code = TREE_CODE (type); |
| |
| if (e == error_mark_node |
| || TREE_TYPE (e) == error_mark_node) |
| return error_mark_node; |
| |
| if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP)) |
| /* We need a new temporary; don't take this shortcut. */; |
| else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e))) |
| /* Trivial conversion: cv-qualifiers do not matter on rvalues. */ |
| return fold (build1 (NOP_EXPR, type, e)); |
| |
| if (code == VOID_TYPE && (convtype & CONV_STATIC)) |
| return build1 (CONVERT_EXPR, type, e); |
| |
| #if 0 |
| /* This is incorrect. A truncation can't be stripped this way. |
| Extensions will be stripped by the use of get_unwidened. */ |
| if (TREE_CODE (e) == NOP_EXPR) |
| return cp_convert (type, TREE_OPERAND (e, 0)); |
| #endif |
| |
| /* Just convert to the type of the member. */ |
| if (code == OFFSET_TYPE) |
| { |
| type = TREE_TYPE (type); |
| code = TREE_CODE (type); |
| } |
| |
| #if 0 |
| if (code == REFERENCE_TYPE) |
| return fold (convert_to_reference (type, e, convtype, flags, NULL_TREE)); |
| else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) |
| e = convert_from_reference (e); |
| #endif |
| |
| if (TREE_CODE (e) == OFFSET_REF) |
| e = resolve_offset_ref (e); |
| |
| if (TREE_READONLY_DECL_P (e)) |
| e = decl_constant_value (e); |
| |
| if (INTEGRAL_CODE_P (code)) |
| { |
| tree intype = TREE_TYPE (e); |
| /* enum = enum, enum = int, enum = float, (enum)pointer are all |
| errors. */ |
| if (flag_int_enum_equivalence == 0 |
| && TREE_CODE (type) == ENUMERAL_TYPE |
| && ((ARITHMETIC_TYPE_P (intype) && ! (convtype & CONV_STATIC)) |
| || (TREE_CODE (intype) == POINTER_TYPE))) |
| { |
| cp_pedwarn ("conversion from `%#T' to `%#T'", intype, type); |
| |
| if (flag_pedantic_errors) |
| return error_mark_node; |
| } |
| if (IS_AGGR_TYPE (intype)) |
| { |
| tree rval; |
| rval = build_type_conversion (CONVERT_EXPR, type, e, 1); |
| if (rval) |
| return rval; |
| if (flags & LOOKUP_COMPLAIN) |
| cp_error ("`%#T' used where a `%T' was expected", intype, type); |
| if (flags & LOOKUP_SPECULATIVELY) |
| return NULL_TREE; |
| return error_mark_node; |
| } |
| if (code == BOOLEAN_TYPE) |
| { |
| /* Common Ada/Pascal programmer's mistake. We always warn |
| about this since it is so bad. */ |
| if (TREE_CODE (expr) == FUNCTION_DECL) |
| cp_warning ("the address of `%D', will always be `true'", expr); |
| return truthvalue_conversion (e); |
| } |
| return fold (convert_to_integer (type, e)); |
| } |
| if (code == POINTER_TYPE || code == REFERENCE_TYPE |
| || TYPE_PTRMEMFUNC_P (type)) |
| return fold (cp_convert_to_pointer (type, e)); |
| if (code == REAL_TYPE || code == COMPLEX_TYPE) |
| { |
| if (IS_AGGR_TYPE (TREE_TYPE (e))) |
| { |
| tree rval; |
| rval = build_type_conversion (CONVERT_EXPR, type, e, 1); |
| if (rval) |
| return rval; |
| else |
| if (flags & LOOKUP_COMPLAIN) |
| cp_error ("`%#T' used where a floating point value was expected", |
| TREE_TYPE (e)); |
| } |
| if (code == REAL_TYPE) |
| return fold (convert_to_real (type, e)); |
| else if (code == COMPLEX_TYPE) |
| return fold (convert_to_complex (type, e)); |
| } |
| |
| /* New C++ semantics: since assignment is now based on |
| memberwise copying, if the rhs type is derived from the |
| lhs type, then we may still do a conversion. */ |
| if (IS_AGGR_TYPE_CODE (code)) |
| { |
| tree dtype = TREE_TYPE (e); |
| tree ctor = NULL_TREE; |
| tree conversion = NULL_TREE; |
| |
| dtype = TYPE_MAIN_VARIANT (dtype); |
| |
| /* Conversion of object pointers or signature pointers/references |
| to signature pointers/references. */ |
| |
| if (TYPE_LANG_SPECIFIC (type) |
| && (IS_SIGNATURE_POINTER (type) || IS_SIGNATURE_REFERENCE (type))) |
| { |
| tree constructor = build_signature_pointer_constructor (type, expr); |
| tree sig_ty = SIGNATURE_TYPE (type); |
| tree sig_ptr; |
| |
| if (constructor == error_mark_node) |
| return error_mark_node; |
| |
| sig_ptr = get_temp_name (type, 1); |
| DECL_INITIAL (sig_ptr) = constructor; |
| CLEAR_SIGNATURE (sig_ty); |
| cp_finish_decl (sig_ptr, constructor, NULL_TREE, 0, 0); |
| SET_SIGNATURE (sig_ty); |
| TREE_READONLY (sig_ptr) = 1; |
| |
| return sig_ptr; |
| } |
| |
| /* Conversion between aggregate types. New C++ semantics allow |
| objects of derived type to be cast to objects of base type. |
| Old semantics only allowed this between pointers. |
| |
| There may be some ambiguity between using a constructor |
| vs. using a type conversion operator when both apply. */ |
| |
| if (flag_ansi_overloading) |
| { |
| ctor = e; |
| |
| if ((flags & LOOKUP_ONLYCONVERTING) |
| && ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype))) |
| ctor = build_user_type_conversion (type, ctor, flags); |
| if (ctor) |
| ctor = build_method_call (NULL_TREE, ctor_identifier, |
| build_tree_list (NULL_TREE, ctor), |
| TYPE_BINFO (type), flags); |
| if (ctor) |
| return build_cplus_new (type, ctor); |
| } |
| else |
| { |
| if (IS_AGGR_TYPE (dtype) && ! DERIVED_FROM_P (type, dtype) |
| && TYPE_HAS_CONVERSION (dtype)) |
| conversion = build_type_conversion (CONVERT_EXPR, type, e, 1); |
| |
| if (conversion == error_mark_node) |
| { |
| if (flags & LOOKUP_COMPLAIN) |
| error ("ambiguous pointer conversion"); |
| return conversion; |
| } |
| |
| if (TYPE_HAS_CONSTRUCTOR (complete_type (type))) |
| ctor = build_method_call (NULL_TREE, ctor_identifier, |
| build_tree_list (NULL_TREE, e), |
| TYPE_BINFO (type), |
| (flags & LOOKUP_NORMAL) |
| | LOOKUP_SPECULATIVELY |
| | (flags & LOOKUP_ONLYCONVERTING) |
| | (flags & LOOKUP_NO_CONVERSION) |
| | (conversion ? LOOKUP_NO_CONVERSION : 0)); |
| |
| if (ctor == error_mark_node) |
| { |
| if (flags & LOOKUP_COMPLAIN) |
| cp_error ("in conversion to type `%T'", type); |
| if (flags & LOOKUP_SPECULATIVELY) |
| return NULL_TREE; |
| return error_mark_node; |
| } |
| |
| if (conversion && ctor) |
| { |
| if (flags & LOOKUP_COMPLAIN) |
| error ("both constructor and type conversion operator apply"); |
| if (flags & LOOKUP_SPECULATIVELY) |
| return NULL_TREE; |
| return error_mark_node; |
| } |
| else if (conversion) |
| return conversion; |
| else if (ctor) |
| { |
| ctor = build_cplus_new (type, ctor); |
| return ctor; |
| } |
| } |
| } |
| |
| /* If TYPE or TREE_TYPE (E) is not on the permanent_obstack, |
| then the it won't be hashed and hence compare as not equal, |
| even when it is. */ |
| if (code == ARRAY_TYPE |
| && TREE_TYPE (TREE_TYPE (e)) == TREE_TYPE (type) |
| && index_type_equal (TYPE_DOMAIN (TREE_TYPE (e)), TYPE_DOMAIN (type))) |
| return e; |
| |
| if (flags & LOOKUP_COMPLAIN) |
| cp_error ("conversion from `%T' to non-scalar type `%T' requested", |
| TREE_TYPE (expr), type); |
| if (flags & LOOKUP_SPECULATIVELY) |
| return NULL_TREE; |
| return error_mark_node; |
| } |
| |
| /* Create an expression whose value is that of EXPR, |
| converted to type TYPE. The TREE_TYPE of the value |
| is always TYPE. This function implements all reasonable |
| conversions; callers should filter out those that are |
| not permitted by the language being compiled. |
| |
| Most of this routine is from build_reinterpret_cast. |
| |
| The backend cannot call cp_convert (what was convert) because |
| conversions to/from basetypes may involve memory references |
| (vbases) and adding or subtracting small values (multiple |
| inheritance), but it calls convert from the constant folding code |
| on subtrees of already build trees after it has ripped them apart. |
| |
| Also, if we ever support range variables, we'll probably also have to |
| do a little bit more work. */ |
| |
| tree |
| convert (type, expr) |
| tree type, expr; |
| { |
| tree intype; |
| |
| if (type == error_mark_node || expr == error_mark_node) |
| return error_mark_node; |
| |
| intype = TREE_TYPE (expr); |
| |
| if (POINTER_TYPE_P (type) && POINTER_TYPE_P (intype)) |
| { |
| if (TREE_READONLY_DECL_P (expr)) |
| expr = decl_constant_value (expr); |
| return fold (build1 (NOP_EXPR, type, expr)); |
| } |
| |
| return ocp_convert (type, expr, CONV_OLD_CONVERT, |
| LOOKUP_NORMAL|LOOKUP_NO_CONVERSION); |
| } |
| |
| /* Like cp_convert, except permit conversions to take place which |
| are not normally allowed due to access restrictions |
| (such as conversion from sub-type to private super-type). */ |
| |
| tree |
| convert_force (type, expr, convtype) |
| tree type; |
| tree expr; |
| int convtype; |
| { |
| register tree e = expr; |
| register enum tree_code code = TREE_CODE (type); |
| |
| if (code == REFERENCE_TYPE) |
| return fold (convert_to_reference (type, e, CONV_C_CAST, LOOKUP_COMPLAIN, |
| NULL_TREE)); |
| else if (TREE_CODE (TREE_TYPE (e)) == REFERENCE_TYPE) |
| e = convert_from_reference (e); |
| |
| if (code == POINTER_TYPE) |
| return fold (convert_to_pointer_force (type, e)); |
| |
| /* From typeck.c convert_for_assignment */ |
| if (((TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE && TREE_CODE (e) == ADDR_EXPR |
| && TREE_CODE (TREE_TYPE (e)) == POINTER_TYPE |
| && TREE_CODE (TREE_TYPE (TREE_TYPE (e))) == METHOD_TYPE) |
| || integer_zerop (e) |
| || TYPE_PTRMEMFUNC_P (TREE_TYPE (e))) |
| && TYPE_PTRMEMFUNC_P (type)) |
| { |
| /* compatible pointer to member functions. */ |
| return build_ptrmemfunc (TYPE_PTRMEMFUNC_FN_TYPE (type), e, 1); |
| } |
| |
| return ocp_convert (type, e, CONV_C_CAST|convtype, LOOKUP_NORMAL); |
| } |
| |
| /* Subroutine of build_type_conversion. */ |
| |
| static tree |
| build_type_conversion_1 (xtype, basetype, expr, typename, for_sure) |
| tree xtype, basetype; |
| tree expr; |
| tree typename; |
| int for_sure; |
| { |
| tree rval; |
| int flags; |
| |
| if (for_sure == 0) |
| flags = LOOKUP_PROTECT|LOOKUP_ONLYCONVERTING; |
| else |
| flags = LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING; |
| |
| rval = build_method_call (expr, typename, NULL_TREE, NULL_TREE, flags); |
| if (rval == error_mark_node) |
| { |
| if (for_sure == 0) |
| return NULL_TREE; |
| return error_mark_node; |
| } |
| |
| if (IS_AGGR_TYPE (TREE_TYPE (rval))) |
| return rval; |
| |
| if (warn_cast_qual |
| && TREE_TYPE (xtype) |
| && (TREE_READONLY (TREE_TYPE (TREE_TYPE (rval))) |
| > TREE_READONLY (TREE_TYPE (xtype)))) |
| warning ("user-defined conversion casting away `const'"); |
| return cp_convert (xtype, rval); |
| } |
| |
| /* Convert an aggregate EXPR to type XTYPE. If a conversion |
| exists, return the attempted conversion. This may |
| return ERROR_MARK_NODE if the conversion is not |
| allowed (references private members, etc). |
| If no conversion exists, NULL_TREE is returned. |
| |
| If (FOR_SURE & 1) is non-zero, then we allow this type conversion |
| to take place immediately. Otherwise, we build a SAVE_EXPR |
| which can be evaluated if the results are ever needed. |
| |
| Changes to this functions should be mirrored in user_harshness. |
| |
| FIXME: Ambiguity checking is wrong. Should choose one by the implicit |
| object parameter, or by the second standard conversion sequence if |
| that doesn't do it. This will probably wait for an overloading rewrite. |
| (jason 8/9/95) */ |
| |
| tree |
| build_type_conversion (code, xtype, expr, for_sure) |
| enum tree_code code; |
| tree xtype, expr; |
| int for_sure; |
| { |
| /* C++: check to see if we can convert this aggregate type |
| into the required type. */ |
| tree basetype; |
| tree conv; |
| tree winner = NULL_TREE; |
| |
| if (flag_ansi_overloading) |
| return build_user_type_conversion |
| (xtype, expr, for_sure ? LOOKUP_NORMAL : 0); |
| |
| if (expr == error_mark_node) |
| return error_mark_node; |
| |
| basetype = TREE_TYPE (expr); |
| if (TREE_CODE (basetype) == REFERENCE_TYPE) |
| basetype = TREE_TYPE (basetype); |
| |
| basetype = TYPE_MAIN_VARIANT (basetype); |
| if (! TYPE_LANG_SPECIFIC (basetype) || ! TYPE_HAS_CONVERSION (basetype)) |
| return NULL_TREE; |
| |
| /* Do we have an exact match? */ |
| { |
| tree typename = build_typename_overload (xtype); |
| if (lookup_fnfields (TYPE_BINFO (basetype), typename, 0)) |
| return build_type_conversion_1 (xtype, basetype, expr, typename, |
| for_sure); |
| } |
| |
| /* Nope; try looking for others. */ |
| for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) |
| { |
| tree cand = TREE_VALUE (conv); |
| |
| if (winner && winner == cand) |
| continue; |
| |
| if (can_convert (xtype, TREE_TYPE (TREE_TYPE (cand)))) |
| { |
| if (winner) |
| { |
| if (for_sure) |
| { |
| cp_error ("ambiguous conversion from `%T' to `%T'", basetype, |
| xtype); |
| cp_error (" candidate conversions include `%D' and `%D'", |
| winner, cand); |
| } |
| return NULL_TREE; |
| } |
| else |
| winner = cand; |
| } |
| } |
| |
| if (winner) |
| return build_type_conversion_1 (xtype, basetype, expr, |
| DECL_NAME (winner), for_sure); |
| |
| return NULL_TREE; |
| } |
| |
| /* Convert the given EXPR to one of a group of types suitable for use in an |
| expression. DESIRES is a combination of various WANT_* flags (q.v.) |
| which indicates which types are suitable. If COMPLAIN is 1, complain |
| about ambiguity; otherwise, the caller will deal with it. */ |
| |
| tree |
| build_expr_type_conversion (desires, expr, complain) |
| int desires; |
| tree expr; |
| int complain; |
| { |
| tree basetype = TREE_TYPE (expr); |
| tree conv; |
| tree winner = NULL_TREE; |
| |
| if (TREE_CODE (basetype) == OFFSET_TYPE) |
| expr = resolve_offset_ref (expr); |
| expr = convert_from_reference (expr); |
| basetype = TREE_TYPE (expr); |
| |
| if (! IS_AGGR_TYPE (basetype)) |
| switch (TREE_CODE (basetype)) |
| { |
| case INTEGER_TYPE: |
| if ((desires & WANT_NULL) && TREE_CODE (expr) == INTEGER_CST |
| && integer_zerop (expr)) |
| return expr; |
| /* else fall through... */ |
| |
| case BOOLEAN_TYPE: |
| return (desires & WANT_INT) ? expr : NULL_TREE; |
| case ENUMERAL_TYPE: |
| return (desires & WANT_ENUM) ? expr : NULL_TREE; |
| case REAL_TYPE: |
| return (desires & WANT_FLOAT) ? expr : NULL_TREE; |
| case POINTER_TYPE: |
| return (desires & WANT_POINTER) ? expr : NULL_TREE; |
| |
| case FUNCTION_TYPE: |
| case ARRAY_TYPE: |
| return (desires & WANT_POINTER) ? default_conversion (expr) |
| : NULL_TREE; |
| default: |
| return NULL_TREE; |
| } |
| |
| if (! TYPE_HAS_CONVERSION (basetype)) |
| return NULL_TREE; |
| |
| for (conv = lookup_conversions (basetype); conv; conv = TREE_CHAIN (conv)) |
| { |
| int win = 0; |
| tree candidate; |
| tree cand = TREE_VALUE (conv); |
| |
| if (winner && winner == cand) |
| continue; |
| |
| candidate = TREE_TYPE (TREE_TYPE (cand)); |
| if (TREE_CODE (candidate) == REFERENCE_TYPE) |
| candidate = TREE_TYPE (candidate); |
| |
| switch (TREE_CODE (candidate)) |
| { |
| case BOOLEAN_TYPE: |
| case INTEGER_TYPE: |
| win = (desires & WANT_INT); break; |
| case ENUMERAL_TYPE: |
| win = (desires & WANT_ENUM); break; |
| case REAL_TYPE: |
| win = (desires & WANT_FLOAT); break; |
| case POINTER_TYPE: |
| win = (desires & WANT_POINTER); break; |
| } |
| |
| if (win) |
| { |
| if (winner) |
| { |
| if (complain) |
| { |
| cp_error ("ambiguous default type conversion from `%T'", |
| basetype); |
| cp_error (" candidate conversions include `%D' and `%D'", |
| winner, cand); |
| } |
| return error_mark_node; |
| } |
| else |
| winner = cand; |
| } |
| } |
| |
| if (winner) |
| { |
| tree type = TREE_TYPE (TREE_TYPE (winner)); |
| if (TREE_CODE (type) == REFERENCE_TYPE) |
| type = TREE_TYPE (type); |
| return build_type_conversion_1 (type, basetype, expr, |
| DECL_NAME (winner), 1); |
| } |
| |
| return NULL_TREE; |
| } |
| |
| /* Must convert two aggregate types to non-aggregate type. |
| Attempts to find a non-ambiguous, "best" type conversion. |
| |
| Return 1 on success, 0 on failure. |
| |
| @@ What are the real semantics of this supposed to be??? */ |
| |
| int |
| build_default_binary_type_conversion (code, arg1, arg2) |
| enum tree_code code; |
| tree *arg1, *arg2; |
| { |
| switch (code) |
| { |
| case MULT_EXPR: |
| case TRUNC_DIV_EXPR: |
| case CEIL_DIV_EXPR: |
| case FLOOR_DIV_EXPR: |
| case ROUND_DIV_EXPR: |
| case EXACT_DIV_EXPR: |
| *arg1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); |
| *arg2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); |
| break; |
| |
| case TRUNC_MOD_EXPR: |
| case FLOOR_MOD_EXPR: |
| case LSHIFT_EXPR: |
| case RSHIFT_EXPR: |
| case BIT_AND_EXPR: |
| case BIT_XOR_EXPR: |
| case BIT_IOR_EXPR: |
| *arg1 = build_expr_type_conversion (WANT_INT | WANT_ENUM, *arg1, 0); |
| *arg2 = build_expr_type_conversion (WANT_INT | WANT_ENUM, *arg2, 0); |
| break; |
| |
| case PLUS_EXPR: |
| { |
| tree a1, a2, p1, p2; |
| int wins; |
| |
| a1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); |
| a2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); |
| p1 = build_expr_type_conversion (WANT_POINTER, *arg1, 0); |
| p2 = build_expr_type_conversion (WANT_POINTER, *arg2, 0); |
| |
| wins = (a1 && a2) + (a1 && p2) + (p1 && a2); |
| |
| if (wins > 1) |
| error ("ambiguous default type conversion for `operator +'"); |
| |
| if (a1 && a2) |
| *arg1 = a1, *arg2 = a2; |
| else if (a1 && p2) |
| *arg1 = a1, *arg2 = p2; |
| else |
| *arg1 = p1, *arg2 = a2; |
| break; |
| } |
| |
| case MINUS_EXPR: |
| { |
| tree a1, a2, p1, p2; |
| int wins; |
| |
| a1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); |
| a2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); |
| p1 = build_expr_type_conversion (WANT_POINTER, *arg1, 0); |
| p2 = build_expr_type_conversion (WANT_POINTER, *arg2, 0); |
| |
| wins = (a1 && a2) + (p1 && p2) + (p1 && a2); |
| |
| if (wins > 1) |
| error ("ambiguous default type conversion for `operator -'"); |
| |
| if (a1 && a2) |
| *arg1 = a1, *arg2 = a2; |
| else if (p1 && p2) |
| *arg1 = p1, *arg2 = p2; |
| else |
| *arg1 = p1, *arg2 = a2; |
| break; |
| } |
| |
| case GT_EXPR: |
| case LT_EXPR: |
| case GE_EXPR: |
| case LE_EXPR: |
| case EQ_EXPR: |
| case NE_EXPR: |
| { |
| tree a1, a2, p1, p2; |
| int wins; |
| |
| a1 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg1, 0); |
| a2 = build_expr_type_conversion (WANT_ARITH | WANT_ENUM, *arg2, 0); |
| p1 = build_expr_type_conversion (WANT_POINTER | WANT_NULL, *arg1, 0); |
| p2 = build_expr_type_conversion (WANT_POINTER | WANT_NULL, *arg2, 0); |
| |
| wins = (a1 && a2) + (p1 && p2); |
| |
| if (wins > 1) |
| cp_error ("ambiguous default type conversion for `%O'", code); |
| |
| if (a1 && a2) |
| *arg1 = a1, *arg2 = a2; |
| else |
| *arg1 = p1, *arg2 = p2; |
| break; |
| } |
| |
| case TRUTH_ANDIF_EXPR: |
| case TRUTH_ORIF_EXPR: |
| *arg1 = cp_convert (boolean_type_node, *arg1); |
| *arg2 = cp_convert (boolean_type_node, *arg2); |
| break; |
| |
| default: |
| *arg1 = NULL_TREE; |
| *arg2 = NULL_TREE; |
| } |
| |
| if (*arg1 == error_mark_node || *arg2 == error_mark_node) |
| cp_error ("ambiguous default type conversion for `%O'", code); |
| |
| if (*arg1 && *arg2) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* Implements integral promotion (4.1) and float->double promotion. */ |
| |
| tree |
| type_promotes_to (type) |
| tree type; |
| { |
| int constp, volatilep; |
| |
| if (type == error_mark_node) |
| return error_mark_node; |
| |
| constp = TYPE_READONLY (type); |
| volatilep = TYPE_VOLATILE (type); |
| type = TYPE_MAIN_VARIANT (type); |
| |
| /* bool always promotes to int (not unsigned), even if it's the same |
| size. */ |
| if (type == boolean_type_node) |
| type = integer_type_node; |
| |
| /* Normally convert enums to int, but convert wide enums to something |
| wider. */ |
| else if (TREE_CODE (type) == ENUMERAL_TYPE |
| || type == wchar_type_node) |
| { |
| int precision = MAX (TYPE_PRECISION (type), |
| TYPE_PRECISION (integer_type_node)); |
| tree totype = type_for_size (precision, 0); |
| if (TREE_UNSIGNED (type) |
| && ! int_fits_type_p (TYPE_MAX_VALUE (type), totype)) |
| type = type_for_size (precision, 1); |
| else |
| type = totype; |
| } |
| else if (C_PROMOTING_INTEGER_TYPE_P (type)) |
| { |
| /* Retain unsignedness if really not getting bigger. */ |
| if (TREE_UNSIGNED (type) |
| && TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) |
| type = unsigned_type_node; |
| else |
| type = integer_type_node; |
| } |
| else if (type == float_type_node) |
| type = double_type_node; |
| |
| return cp_build_type_variant (type, constp, volatilep); |
| } |