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typeck.c
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/* Build expressions with type checking for C++ compiler.
Copyright (C) 1987, 88, 89, 92-96, 1997 Free Software Foundation, Inc.
Hacked by Michael Tiemann ([email protected])
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 is part of the C++ front end.
It contains routines to build C++ expressions given their operands,
including computing the types of the result, C and C++ specific error
checks, and some optimization.
There are also routines to build RETURN_STMT nodes and CASE_STMT nodes,
and to process initializations in declarations (since they work
like a strange sort of assignment). */
#include "config.h"
#include <stdio.h>
#include "tree.h"
#include "rtl.h"
#include "cp-tree.h"
#include "flags.h"
#include "output.h"
#include "expr.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif
extern void compiler_error ();
static tree convert_for_assignment PROTO((tree, tree, char*, tree,
int));
static tree pointer_int_sum PROTO((enum tree_code, tree, tree));
static tree rationalize_conditional_expr PROTO((enum tree_code, tree));
static int comp_target_parms PROTO((tree, tree, int));
static int comp_ptr_ttypes_real PROTO((tree, tree, int));
static int comp_ptr_ttypes_const PROTO((tree, tree));
static int comp_ptr_ttypes_reinterpret PROTO((tree, tree));
static int comp_array_types PROTO((int (*) (tree, tree, int), tree,
tree, int));
static tree build_ptrmemfunc1 PROTO((tree, tree, tree, tree, tree));
static tree common_base_type PROTO((tree, tree));
static tree convert_sequence PROTO((tree, tree));
static tree lookup_anon_field PROTO((tree, tree));
static tree pointer_diff PROTO((tree, tree));
static tree qualify_type PROTO((tree, tree));
static tree expand_target_expr PROTO((tree));
static tree get_delta_difference PROTO((tree, tree, int));
/* Return the target type of TYPE, which meas return T for:
T*, T&, T[], T (...), and otherwise, just T. */
tree
target_type (type)
tree type;
{
if (TREE_CODE (type) == REFERENCE_TYPE)
type = TREE_TYPE (type);
while (TREE_CODE (type) == POINTER_TYPE
|| TREE_CODE (type) == ARRAY_TYPE
|| TREE_CODE (type) == FUNCTION_TYPE
|| TREE_CODE (type) == METHOD_TYPE
|| TREE_CODE (type) == OFFSET_TYPE)
type = TREE_TYPE (type);
return type;
}
/* Do `exp = require_complete_type (exp);' to make sure exp
does not have an incomplete type. (That includes void types.) */
tree
require_complete_type (value)
tree value;
{
tree type;
if (processing_template_decl)
return value;
type = TREE_TYPE (value);
/* First, detect a valid value with a complete type. */
if (TYPE_SIZE (type) != 0
&& type != void_type_node
&& ! (TYPE_LANG_SPECIFIC (type)
&& (IS_SIGNATURE_POINTER (type) || IS_SIGNATURE_REFERENCE (type))
&& TYPE_SIZE (SIGNATURE_TYPE (type)) == 0))
return value;
/* If we see X::Y, we build an OFFSET_TYPE which has
not been laid out. Try to avoid an error by interpreting
it as this->X::Y, if reasonable. */
if (TREE_CODE (value) == OFFSET_REF
&& current_class_ref != 0
&& TREE_OPERAND (value, 0) == current_class_ref)
{
tree base, member = TREE_OPERAND (value, 1);
tree basetype = TYPE_OFFSET_BASETYPE (type);
my_friendly_assert (TREE_CODE (member) == FIELD_DECL, 305);
base = convert_pointer_to (basetype, current_class_ptr);
value = build (COMPONENT_REF, TREE_TYPE (member),
build_indirect_ref (base, NULL_PTR), member);
return require_complete_type (value);
}
if (IS_AGGR_TYPE (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type))
{
instantiate_class_template (TYPE_MAIN_VARIANT (type));
if (TYPE_SIZE (type) != 0)
return value;
}
incomplete_type_error (value, type);
return error_mark_node;
}
tree
complete_type (type)
tree type;
{
if (type == error_mark_node || TYPE_SIZE (type) != NULL_TREE)
;
else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
{
tree t = complete_type (TREE_TYPE (type));
if (TYPE_SIZE (t) != NULL_TREE && ! processing_template_decl)
layout_type (type);
TYPE_NEEDS_CONSTRUCTING (type)
= TYPE_NEEDS_CONSTRUCTING (TYPE_MAIN_VARIANT (t));
TYPE_NEEDS_DESTRUCTOR (type)
= TYPE_NEEDS_DESTRUCTOR (TYPE_MAIN_VARIANT (t));
}
else if (IS_AGGR_TYPE (type) && CLASSTYPE_TEMPLATE_INSTANTIATION (type))
instantiate_class_template (TYPE_MAIN_VARIANT (type));
return type;
}
/* Return truthvalue of whether type of EXP is instantiated. */
int
type_unknown_p (exp)
tree exp;
{
return (TREE_CODE (exp) == TREE_LIST
|| TREE_TYPE (exp) == unknown_type_node
|| (TREE_CODE (TREE_TYPE (exp)) == OFFSET_TYPE
&& TREE_TYPE (TREE_TYPE (exp)) == unknown_type_node));
}
/* Return truthvalue of whether T is function (or pfn) type. */
int
fntype_p (t)
tree t;
{
return (TREE_CODE (t) == FUNCTION_TYPE || TREE_CODE (t) == METHOD_TYPE
|| (TREE_CODE (t) == POINTER_TYPE
&& (TREE_CODE (TREE_TYPE (t)) == FUNCTION_TYPE
|| TREE_CODE (TREE_TYPE (t)) == METHOD_TYPE)));
}
/* Do `exp = require_instantiated_type (type, exp);' to make sure EXP
does not have an uninstantiated type.
TYPE is type to instantiate with, if uninstantiated. */
tree
require_instantiated_type (type, exp, errval)
tree type, exp, errval;
{
if (TREE_TYPE (exp) == NULL_TREE)
{
error ("argument list may not have an initializer list");
return errval;
}
if (TREE_TYPE (exp) == unknown_type_node
|| (TREE_CODE (TREE_TYPE (exp)) == OFFSET_TYPE
&& TREE_TYPE (TREE_TYPE (exp)) == unknown_type_node))
{
exp = instantiate_type (type, exp, 1);
if (TREE_TYPE (exp) == error_mark_node)
return errval;
}
return exp;
}
/* Return a variant of TYPE which has all the type qualifiers of LIKE
as well as those of TYPE. */
static tree
qualify_type (type, like)
tree type, like;
{
int constflag = TYPE_READONLY (type) || TYPE_READONLY (like);
int volflag = TYPE_VOLATILE (type) || TYPE_VOLATILE (like);
/* @@ Must do member pointers here. */
return cp_build_type_variant (type, constflag, volflag);
}
/* Return the common type of two parameter lists.
We assume that comptypes has already been done and returned 1;
if that isn't so, this may crash.
As an optimization, free the space we allocate if the parameter
lists are already common. */
tree
commonparms (p1, p2)
tree p1, p2;
{
tree oldargs = p1, newargs, n;
int i, len;
int any_change = 0;
char *first_obj = (char *) oballoc (0);
len = list_length (p1);
newargs = tree_last (p1);
if (newargs == void_list_node)
i = 1;
else
{
i = 0;
newargs = 0;
}
for (; i < len; i++)
newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
n = newargs;
for (i = 0; p1;
p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n), i++)
{
if (TREE_PURPOSE (p1) && !TREE_PURPOSE (p2))
{
TREE_PURPOSE (n) = TREE_PURPOSE (p1);
any_change = 1;
}
else if (! TREE_PURPOSE (p1))
{
if (TREE_PURPOSE (p2))
{
TREE_PURPOSE (n) = TREE_PURPOSE (p2);
any_change = 1;
}
}
else
{
if (1 != simple_cst_equal (TREE_PURPOSE (p1), TREE_PURPOSE (p2)))
any_change = 1;
TREE_PURPOSE (n) = TREE_PURPOSE (p2);
}
if (TREE_VALUE (p1) != TREE_VALUE (p2))
{
any_change = 1;
TREE_VALUE (n) = common_type (TREE_VALUE (p1), TREE_VALUE (p2));
}
else
TREE_VALUE (n) = TREE_VALUE (p1);
}
if (! any_change)
{
obfree (first_obj);
return oldargs;
}
return newargs;
}
/* Return the common type of two types.
We assume that comptypes has already been done and returned 1;
if that isn't so, this may crash.
This is the type for the result of most arithmetic operations
if the operands have the given two types.
We do not deal with enumeral types here because they have already been
converted to integer types. */
tree
common_type (t1, t2)
tree t1, t2;
{
register enum tree_code code1;
register enum tree_code code2;
tree attributes;
/* Save time if the two types are the same. */
if (t1 == t2) return t1;
/* If one type is nonsense, use the other. */
if (t1 == error_mark_node)
return t2;
if (t2 == error_mark_node)
return t1;
/* Merge the attributes */
{ register tree a1, a2;
a1 = TYPE_ATTRIBUTES (t1);
a2 = TYPE_ATTRIBUTES (t2);
/* Either one unset? Take the set one. */
if (!(attributes = a1))
attributes = a2;
/* One that completely contains the other? Take it. */
else if (a2 && !attribute_list_contained (a1, a2))
if (attribute_list_contained (a2, a1))
attributes = a2;
else
{
/* Pick the longest list, and hang on the other list. */
/* ??? For the moment we punt on the issue of attrs with args. */
if (list_length (a1) < list_length (a2))
attributes = a2, a2 = a1;
for (; a2; a2 = TREE_CHAIN (a2))
if (lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
attributes) == NULL_TREE)
{
a1 = copy_node (a2);
TREE_CHAIN (a1) = attributes;
attributes = a1;
}
}
}
/* Treat an enum type as the unsigned integer type of the same width. */
if (TREE_CODE (t1) == ENUMERAL_TYPE)
t1 = type_for_size (TYPE_PRECISION (t1), 1);
if (TREE_CODE (t2) == ENUMERAL_TYPE)
t2 = type_for_size (TYPE_PRECISION (t2), 1);
if (TYPE_PTRMEMFUNC_P (t1))
t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1);
if (TYPE_PTRMEMFUNC_P (t2))
t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2);
code1 = TREE_CODE (t1);
code2 = TREE_CODE (t2);
/* If one type is complex, form the common type of the non-complex
components, then make that complex. Use T1 or T2 if it is the
required type. */
if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
{
tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
tree subtype = common_type (subtype1, subtype2);
if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
return build_type_attribute_variant (t1, attributes);
else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
return build_type_attribute_variant (t2, attributes);
else
return build_type_attribute_variant (build_complex_type (subtype),
attributes);
}
switch (code1)
{
case INTEGER_TYPE:
case REAL_TYPE:
/* If only one is real, use it as the result. */
if (code1 == REAL_TYPE && code2 != REAL_TYPE)
return build_type_attribute_variant (t1, attributes);
if (code2 == REAL_TYPE && code1 != REAL_TYPE)
return build_type_attribute_variant (t2, attributes);
/* Both real or both integers; use the one with greater precision. */
if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
return build_type_attribute_variant (t1, attributes);
else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
return build_type_attribute_variant (t2, attributes);
/* Same precision. Prefer longs to ints even when same size. */
if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
|| TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
return build_type_attribute_variant (long_unsigned_type_node,
attributes);
if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
|| TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
{
/* But preserve unsignedness from the other type,
since long cannot hold all the values of an unsigned int. */
if (TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2))
t1 = long_unsigned_type_node;
else
t1 = long_integer_type_node;
return build_type_attribute_variant (t1, attributes);
}
if (TYPE_MAIN_VARIANT (t1) == long_double_type_node
|| TYPE_MAIN_VARIANT (t2) == long_double_type_node)
return build_type_attribute_variant (long_double_type_node,
attributes);
/* Otherwise prefer the unsigned one. */
if (TREE_UNSIGNED (t1))
return build_type_attribute_variant (t1, attributes);
else
return build_type_attribute_variant (t2, attributes);
case POINTER_TYPE:
case REFERENCE_TYPE:
/* For two pointers, do this recursively on the target type,
and combine the qualifiers of the two types' targets. */
/* This code was turned off; I don't know why.
But ANSI C++ specifies doing this with the qualifiers.
So I turned it on again. */
{
tree tt1 = TYPE_MAIN_VARIANT (TREE_TYPE (t1));
tree tt2 = TYPE_MAIN_VARIANT (TREE_TYPE (t2));
int constp
= TYPE_READONLY (TREE_TYPE (t1)) || TYPE_READONLY (TREE_TYPE (t2));
int volatilep
= TYPE_VOLATILE (TREE_TYPE (t1)) || TYPE_VOLATILE (TREE_TYPE (t2));
tree target;
if (tt1 == tt2)
target = tt1;
else if (tt1 == void_type_node || tt2 == void_type_node)
target = void_type_node;
else if (tt1 == unknown_type_node)
target = tt2;
else if (tt2 == unknown_type_node)
target = tt1;
else
target = common_type (tt1, tt2);
target = cp_build_type_variant (target, constp, volatilep);
if (code1 == POINTER_TYPE)
t1 = build_pointer_type (target);
else
t1 = build_reference_type (target);
t1 = build_type_attribute_variant (t1, attributes);
if (TREE_CODE (target) == METHOD_TYPE)
t1 = build_ptrmemfunc_type (t1);
return t1;
}
case ARRAY_TYPE:
{
tree elt = common_type (TREE_TYPE (t1), TREE_TYPE (t2));
/* Save space: see if the result is identical to one of the args. */
if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
return build_type_attribute_variant (t1, attributes);
if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
return build_type_attribute_variant (t2, attributes);
/* Merge the element types, and have a size if either arg has one. */
t1 = build_cplus_array_type
(elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
return build_type_attribute_variant (t1, attributes);
}
case FUNCTION_TYPE:
/* Function types: prefer the one that specified arg types.
If both do, merge the arg types. Also merge the return types. */
{
tree valtype = common_type (TREE_TYPE (t1), TREE_TYPE (t2));
tree p1 = TYPE_ARG_TYPES (t1);
tree p2 = TYPE_ARG_TYPES (t2);
tree rval, raises;
/* Save space: see if the result is identical to one of the args. */
if (valtype == TREE_TYPE (t1) && ! p2)
return build_type_attribute_variant (t1, attributes);
if (valtype == TREE_TYPE (t2) && ! p1)
return build_type_attribute_variant (t2, attributes);
/* Simple way if one arg fails to specify argument types. */
if (p1 == NULL_TREE || TREE_VALUE (p1) == void_type_node)
{
rval = build_function_type (valtype, p2);
if ((raises = TYPE_RAISES_EXCEPTIONS (t2)))
rval = build_exception_variant (rval, raises);
return build_type_attribute_variant (rval, attributes);
}
raises = TYPE_RAISES_EXCEPTIONS (t1);
if (p2 == NULL_TREE || TREE_VALUE (p2) == void_type_node)
{
rval = build_function_type (valtype, p1);
if (raises)
rval = build_exception_variant (rval, raises);
return build_type_attribute_variant (rval, attributes);
}
rval = build_function_type (valtype, commonparms (p1, p2));
rval = build_exception_variant (rval, raises);
return build_type_attribute_variant (rval, attributes);
}
case RECORD_TYPE:
case UNION_TYPE:
my_friendly_assert (TYPE_MAIN_VARIANT (t1) == t1
&& TYPE_MAIN_VARIANT (t2) == t2, 306);
if (DERIVED_FROM_P (t1, t2) && binfo_or_else (t1, t2))
return build_type_attribute_variant (t1, attributes);
else if (binfo_or_else (t2, t1))
return build_type_attribute_variant (t2, attributes);
else
compiler_error ("common_type called with uncommon aggregate types");
case METHOD_TYPE:
if (TREE_CODE (TREE_TYPE (t1)) == TREE_CODE (TREE_TYPE (t2)))
{
/* Get this value the long way, since TYPE_METHOD_BASETYPE
is just the main variant of this. */
tree basetype;
tree raises, t3;
tree b1 = TYPE_OFFSET_BASETYPE (t1);
tree b2 = TYPE_OFFSET_BASETYPE (t2);
if (comptypes (b1, b2, 1)
|| (DERIVED_FROM_P (b1, b2) && binfo_or_else (b1, b2)))
basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t2)));
else
{
if (binfo_or_else (b2, b1) == NULL_TREE)
compiler_error ("common_type called with uncommon method types");
basetype = TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (t1)));
}
raises = TYPE_RAISES_EXCEPTIONS (t1);
/* If this was a member function type, get back to the
original type of type member function (i.e., without
the class instance variable up front. */
t1 = build_function_type (TREE_TYPE (t1), TREE_CHAIN (TYPE_ARG_TYPES (t1)));
t2 = build_function_type (TREE_TYPE (t2), TREE_CHAIN (TYPE_ARG_TYPES (t2)));
t3 = common_type (t1, t2);
t3 = build_cplus_method_type (basetype, TREE_TYPE (t3), TYPE_ARG_TYPES (t3));
t1 = build_exception_variant (t3, raises);
}
else
compiler_error ("common_type called with uncommon method types");
return build_type_attribute_variant (t1, attributes);
case OFFSET_TYPE:
if (TREE_TYPE (t1) == TREE_TYPE (t2))
{
tree b1 = TYPE_OFFSET_BASETYPE (t1);
tree b2 = TYPE_OFFSET_BASETYPE (t2);
if (comptypes (b1, b2, 1)
|| (DERIVED_FROM_P (b1, b2) && binfo_or_else (b1, b2)))
return build_type_attribute_variant (t2, attributes);
else if (binfo_or_else (b2, b1))
return build_type_attribute_variant (t1, attributes);
}
compiler_error ("common_type called with uncommon member types");
default:
return build_type_attribute_variant (t1, attributes);
}
}
/* Return 1 if TYPE1 and TYPE2 raise the same exceptions. */
int
compexcepttypes (t1, t2)
tree t1, t2;
{
return TYPE_RAISES_EXCEPTIONS (t1) == TYPE_RAISES_EXCEPTIONS (t2);
}
static int
comp_array_types (cmp, t1, t2, strict)
register int (*cmp) PROTO((tree, tree, int));
tree t1, t2;
int strict;
{
tree d1 = TYPE_DOMAIN (t1);
tree d2 = TYPE_DOMAIN (t2);
/* Target types must match incl. qualifiers. */
if (!(TREE_TYPE (t1) == TREE_TYPE (t2)
|| (*cmp) (TREE_TYPE (t1), TREE_TYPE (t2), strict)))
return 0;
/* Sizes must match unless one is missing or variable. */
if (d1 == 0 || d2 == 0 || d1 == d2
|| TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
|| TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
|| TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST
|| TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST)
return 1;
return ((TREE_INT_CST_LOW (TYPE_MIN_VALUE (d1))
== TREE_INT_CST_LOW (TYPE_MIN_VALUE (d2)))
&& (TREE_INT_CST_HIGH (TYPE_MIN_VALUE (d1))
== TREE_INT_CST_HIGH (TYPE_MIN_VALUE (d2)))
&& (TREE_INT_CST_LOW (TYPE_MAX_VALUE (d1))
== TREE_INT_CST_LOW (TYPE_MAX_VALUE (d2)))
&& (TREE_INT_CST_HIGH (TYPE_MAX_VALUE (d1))
== TREE_INT_CST_HIGH (TYPE_MAX_VALUE (d2))));
}
/* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
or various other operations. This is what ANSI C++ speaks of as
"being the same".
For C++: argument STRICT says we should be strict about this
comparison:
2 : strict, except that if one type is a reference and
the other is not, compare the target type of the
reference to the type that's not a reference (ARM, p308).
This is used for checking for invalid overloading.
1 : strict (compared according to ANSI C)
This is used for checking whether two function decls match.
0 : <= (compared according to C++)
-1: <= or >= (relaxed)
Otherwise, pointers involving base classes and derived classes
can be mixed as valid: i.e. a pointer to a base class may be assigned
to a pointer to one of its derived classes, as per C++. A pointer to
a derived class may be passed as a parameter to a function expecting a
pointer to a base classes. These allowances do not commute. In this
case, TYPE1 is assumed to be the base class, and TYPE2 is assumed to
be the derived class. */
int
comptypes (type1, type2, strict)
tree type1, type2;
int strict;
{
register tree t1 = type1;
register tree t2 = type2;
int attrval, val;
/* Suppress errors caused by previously reported errors */
if (t1 == t2)
return 1;
/* This should never happen. */
my_friendly_assert (t1 != error_mark_node, 307);
if (t2 == error_mark_node)
return 0;
if (strict < 0)
{
/* Treat an enum type as the unsigned integer type of the same width. */
if (TREE_CODE (t1) == ENUMERAL_TYPE)
t1 = type_for_size (TYPE_PRECISION (t1), 1);
if (TREE_CODE (t2) == ENUMERAL_TYPE)
t2 = type_for_size (TYPE_PRECISION (t2), 1);
if (t1 == t2)
return 1;
}
if (TYPE_PTRMEMFUNC_P (t1))
t1 = TYPE_PTRMEMFUNC_FN_TYPE (t1);
if (TYPE_PTRMEMFUNC_P (t2))
t2 = TYPE_PTRMEMFUNC_FN_TYPE (t2);
/* Different classes of types can't be compatible. */
if (TREE_CODE (t1) != TREE_CODE (t2))
{
if (strict == 2
&& ((TREE_CODE (t1) == REFERENCE_TYPE)
^ (TREE_CODE (t2) == REFERENCE_TYPE)))
{
if (TREE_CODE (t1) == REFERENCE_TYPE)
return comptypes (TREE_TYPE (t1), t2, 1);
return comptypes (t1, TREE_TYPE (t2), 1);
}
return 0;
}
if (strict > 1)
strict = 1;
/* Qualifiers must match. */
if (TYPE_READONLY (t1) != TYPE_READONLY (t2))
return 0;
if (TYPE_VOLATILE (t1) != TYPE_VOLATILE (t2))
return 0;
/* Allow for two different type nodes which have essentially the same
definition. Note that we already checked for equality of the type
type qualifiers (just above). */
if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
return 1;
/* ??? COMP_TYPE_ATTRIBUTES is currently useless for variables as each
attribute is its own main variant (`val' will remain 0). */
#ifndef COMP_TYPE_ATTRIBUTES
#define COMP_TYPE_ATTRIBUTES(t1,t2) 1
#endif
/* 1 if no need for warning yet, 2 if warning cause has been seen. */
if (! (attrval = COMP_TYPE_ATTRIBUTES (t1, t2)))
return 0;
/* 1 if no need for warning yet, 2 if warning cause has been seen. */
val = 0;
switch (TREE_CODE (t1))
{
case RECORD_TYPE:
case UNION_TYPE:
if (CLASSTYPE_TEMPLATE_INFO (t1) && CLASSTYPE_TEMPLATE_INFO (t2)
&& CLASSTYPE_TI_TEMPLATE (t1) == CLASSTYPE_TI_TEMPLATE (t2))
{
int i = TREE_VEC_LENGTH (CLASSTYPE_TI_ARGS (t1));
tree *p1 = &TREE_VEC_ELT (CLASSTYPE_TI_ARGS (t1), 0);
tree *p2 = &TREE_VEC_ELT (CLASSTYPE_TI_ARGS (t2), 0);
while (i--)
{
if (TREE_CODE_CLASS (TREE_CODE (p1[i])) == 't')
{
if (! comptypes (p1[i], p2[i], 1))
return 0;
}
else
{
if (simple_cst_equal (p1[i], p2[i]) <= 0)
return 0;
}
}
return 1;
}
if (strict <= 0)
goto look_hard;
return 0;
case OFFSET_TYPE:
val = (comptypes (build_pointer_type (TYPE_OFFSET_BASETYPE (t1)),
build_pointer_type (TYPE_OFFSET_BASETYPE (t2)), strict)
&& comptypes (TREE_TYPE (t1), TREE_TYPE (t2), strict));
break;
case METHOD_TYPE:
if (! compexcepttypes (t1, t2))
return 0;
/* This case is anti-symmetrical!
One can pass a base member (or member function)
to something expecting a derived member (or member function),
but not vice-versa! */
val = (comptypes (TREE_TYPE (t1), TREE_TYPE (t2), strict)
&& compparms (TYPE_ARG_TYPES (t1),
TYPE_ARG_TYPES (t2), strict));
break;
case POINTER_TYPE:
case REFERENCE_TYPE:
t1 = TREE_TYPE (t1);
t2 = TREE_TYPE (t2);
if (t1 == t2)
{
val = 1;
break;
}
if (strict <= 0)
{
if (TREE_CODE (t1) == RECORD_TYPE && TREE_CODE (t2) == RECORD_TYPE)
{
int rval;
look_hard:
rval = t1 == t2 || DERIVED_FROM_P (t1, t2);
if (rval)
{
val = 1;
break;
}
if (strict < 0)
{
val = DERIVED_FROM_P (t2, t1);
break;
}
}
return 0;
}
else
val = comptypes (t1, t2, strict);
break;
case FUNCTION_TYPE:
if (! compexcepttypes (t1, t2))
return 0;
val = ((TREE_TYPE (t1) == TREE_TYPE (t2)
|| comptypes (TREE_TYPE (t1), TREE_TYPE (t2), strict))
&& compparms (TYPE_ARG_TYPES (t1), TYPE_ARG_TYPES (t2), strict));
break;
case ARRAY_TYPE:
/* Target types must match incl. qualifiers. */
val = comp_array_types (comptypes, t1, t2, strict);
break;
case TEMPLATE_TYPE_PARM:
return TEMPLATE_TYPE_IDX (t1) == TEMPLATE_TYPE_IDX (t2)
&& TEMPLATE_TYPE_LEVEL (t1) == TEMPLATE_TYPE_LEVEL (t2);
case TYPENAME_TYPE:
if (TYPE_IDENTIFIER (t1) != TYPE_IDENTIFIER (t2))
return 0;
return comptypes (TYPE_CONTEXT (t1), TYPE_CONTEXT (t2), 1);
}
return attrval == 2 && val == 1 ? 2 : val;
}
/* Return 1 if TTL and TTR are pointers to types that are equivalent,
ignoring their qualifiers.
NPTRS is the number of pointers we can strip off and keep cool.
This is used to permit (for aggr A, aggr B) A, B* to convert to A*,
but to not permit B** to convert to A**. */
int
comp_target_types (ttl, ttr, nptrs)
tree ttl, ttr;
int nptrs;
{
ttl = TYPE_MAIN_VARIANT (ttl);
ttr = TYPE_MAIN_VARIANT (ttr);
if (ttl == ttr)
return 1;
if (TREE_CODE (ttr) != TREE_CODE (ttl))
return 0;
if (TREE_CODE (ttr) == POINTER_TYPE)
{
ttl = TREE_TYPE (ttl);
ttr = TREE_TYPE (ttr);
if (nptrs > 0)
{
if (TREE_CODE (ttl) == UNKNOWN_TYPE
|| TREE_CODE (ttr) == UNKNOWN_TYPE)
return 1;
else if (TREE_CODE (ttl) == VOID_TYPE
&& TREE_CODE (ttr) != FUNCTION_TYPE
&& TREE_CODE (ttr) != METHOD_TYPE
&& TREE_CODE (ttr) != OFFSET_TYPE)
return 1;
else if (TREE_CODE (ttr) == VOID_TYPE
&& TREE_CODE (ttl) != FUNCTION_TYPE
&& TREE_CODE (ttl) != METHOD_TYPE
&& TREE_CODE (ttl) != OFFSET_TYPE)
return -1;
else if (TREE_CODE (ttl) == POINTER_TYPE
|| TREE_CODE (ttl) == ARRAY_TYPE)
{
if (comp_ptr_ttypes (ttl, ttr))
return 1;
else if (comp_ptr_ttypes (ttr, ttl))
return -1;
return 0;
}
}
/* Const and volatile mean something different for function types,
so the usual checks are not appropriate. */
if (TREE_CODE (ttl) == FUNCTION_TYPE || TREE_CODE (ttl) == METHOD_TYPE)
return comp_target_types (ttl, ttr, nptrs - 1);
/* Make sure that the cv-quals change only in the same direction as
the target type. */
{
int t;
int c = TYPE_READONLY (ttl) - TYPE_READONLY (ttr);
int v = TYPE_VOLATILE (ttl) - TYPE_VOLATILE (ttr);
if ((c > 0 && v < 0) || (c < 0 && v > 0))
return 0;
if (TYPE_MAIN_VARIANT (ttl) == TYPE_MAIN_VARIANT (ttr))
return (c + v < 0) ? -1 : 1;
t = comp_target_types (ttl, ttr, nptrs - 1);
if ((t == 1 && c + v >= 0) || (t == -1 && c + v <= 0))
return t;
return 0;
}
}
if (TREE_CODE (ttr) == REFERENCE_TYPE)
return comp_target_types (TREE_TYPE (ttl), TREE_TYPE (ttr), nptrs);
if (TREE_CODE (ttr) == ARRAY_TYPE)
return comp_array_types (comp_target_types, ttl, ttr, 0);
else if (TREE_CODE (ttr) == FUNCTION_TYPE || TREE_CODE (ttr) == METHOD_TYPE)
if (comp_target_types (TREE_TYPE (ttl), TREE_TYPE (ttr), nptrs))
switch (comp_target_parms (TYPE_ARG_TYPES (ttl), TYPE_ARG_TYPES (ttr), 1))
{
case 0:
return 0;
case 1:
return 1;
case 2:
return -1;
default:
my_friendly_abort (112);
}
else
return 0;
/* for C++ */
else if (TREE_CODE (ttr) == OFFSET_TYPE)
{
/* Contravariance: we can assign a pointer to base member to a pointer
to derived member. Note difference from simple pointer case, where
we can pass a pointer to derived to a pointer to base. */
if (comptypes (TYPE_OFFSET_BASETYPE (ttr), TYPE_OFFSET_BASETYPE (ttl), 0))
return comp_target_types (TREE_TYPE (ttl), TREE_TYPE (ttr), nptrs);
else if (comptypes (TYPE_OFFSET_BASETYPE (ttl), TYPE_OFFSET_BASETYPE (ttr), 0)
&& comp_target_types (TREE_TYPE (ttl), TREE_TYPE (ttr), nptrs))
return -1;
}
else if (IS_AGGR_TYPE (ttl))
{
if (nptrs < 0)
return 0;
if (comptypes (build_pointer_type (ttl), build_pointer_type (ttr), 0))
return 1;
if (comptypes (build_pointer_type (ttr), build_pointer_type (ttl), 0))
return -1;
return 0;
}
return 0;
}
/* If two types share a common base type, return that basetype.
If there is not a unique most-derived base type, this function
returns ERROR_MARK_NODE. */
static tree
common_base_type (tt1, tt2)
tree tt1, tt2;
{
tree best = NULL_TREE;
int i;
/* If one is a baseclass of another, that's good enough. */
if (UNIQUELY_DERIVED_FROM_P (tt1, tt2))
return tt1;
if (UNIQUELY_DERIVED_FROM_P (tt2, tt1))
return tt2;
/* Otherwise, try to find a unique baseclass of TT1
that is shared by TT2, and follow that down. */
for (i = CLASSTYPE_N_BASECLASSES (tt1)-1; i >= 0; i--)
{
tree basetype = TYPE_BINFO_BASETYPE (tt1, i);
tree trial = common_base_type (basetype, tt2);
if (trial)
{
if (trial == error_mark_node)
return trial;