2
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mirror of git://gcc.gnu.org/git/gcc.git synced 2024-12-23 12:59:35 +08:00
gcc/gcc/cp/cvt.c
Mark Mitchell 3bfdc7190f cp-tree.h (COMPARE_STRICT): New macro.
* cp-tree.h (COMPARE_STRICT): New macro.
	(COMPARE_BASE): Likewise.
	(COMPARE_RELAXED): Likewise.
	(COMPARE_REDECLARATION): Likewise.
	(same_type_p): Likewise.
	(same_or_base_type_p): Likewise.
	* call.c (standard_conversion): Use them, in place of comptypes
	with numeric arguments.
	(reference_binding): Likewise.
	(convert_like): Likewise.
	(build_over_call): Likewise.
	(is_subseq): Likewise.
	(is_properly_derived_from): Likewise.
	(compare_ics): Likewise.
	(joust): Likewise.
	* class.c (delete_duplicate_fields_1): Likewise.
	(resolves_to_fixed_type_p): Likewise.
	(instantiate_type): Likewise.  Remove #if 0'd code.
	* decl.c (decls_match): Likewise.  Use COMPARE_REDECLARATION here.
	(pushdecl): Likewise.
	(lookup_name_real): Likewise.
	(grokdeclarator): Likewise.  Check for illegal array declarations.
	(grokparms): Likewise.
	(grok_op_properties): Likewise.
	* decl2.c (check_classfn): Likewise.
	* friend.c (is_friend): Likewise.
	(make_friend_class): Likewise.
	* init.c (expand_aggr_init): Likewise.
	(expand_vec_init): Likewise.
	* pt.c (is_member_template_class): Remove declaration.
	(is_specialization_of): Use COMPARE_* and new macros.
	(comp_template_parms): Likewise.
	(convert_nontype_argument): Likewise.
	(coerce_template_template_parms): Likewise.
	(template_args_equal): Likewise.
	(lookup_template_class): Likewise.
	(type_unification_real): Likewise.
	(unify): Likewise.
	(get_bindings_real): Likewise.
	* search.c (covariant_return_p): Likewise.
	(get_matching_virtual): Likewise.
	* sig.c (match_method_types): Likewise.
	* tree.c (vec_binfo_member): Likewise.
	(cp_tree_equal): Likewise.
	* typeck.c (common_type): Likewise.
	(comp_array_types): Likewise.  Get issues involving unknown array
	bounds right.
	(comptypes): Update comments.  Use new flags.
	(comp_target_types): Use new macros.
	(compparms): Likewise.
	(comp_target_parms): Likewise.
	(string_conv_p): Likewise.
	(build_component_ref): Likewise.
	(build_indirect_ref): Likewise.
	(build_conditional_expr): Likewise.
	(build_static_cast): Likewise.
	(build_reinterpret_cast): Likewise.
	(build_const_cast): Likewise.
	(build_modify_expr): Likewise.
	(convert_for_assignment): Likewise.
	(comp_ptr_ttypes_real): Likewise.
	(ptr_reasonably_similar): Likewise.
	(comp_ptr_ttypes_const): Likewise.

From-SVN: r23490
1998-11-01 15:45:11 +00:00

1130 lines
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/* Language-level data type conversion for GNU C++.
Copyright (C) 1987, 88, 92-96, 1998 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 "system.h"
#include "tree.h"
#include "flags.h"
#include "cp-tree.h"
#include "convert.h"
extern tree static_aggregates;
static tree cp_convert_to_pointer PROTO((tree, tree));
static tree convert_to_pointer_force PROTO((tree, tree));
static tree build_up_reference PROTO((tree, tree, int));
/* 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'. */
/* 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;
tree rval;
if (IS_AGGR_TYPE (intype))
{
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 fntype = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (intype));
tree decl = maybe_dummy_object (TYPE_METHOD_BASETYPE (fntype), 0);
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
/* If EXPR is NULL, then we don't need to do any arithmetic
to convert it:
[conv.ptr]
The null pointer value is converted to the null pointer
value of the destination type. */
&& !integer_zerop (expr))
{
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 build_ptrmemfunc (type, expr, 1);
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 (b2, b1, 1);
enum tree_code code = PLUS_EXPR;
if (binfo == NULL_TREE)
{
binfo = get_binfo (b1, b2, 1);
code = MINUS_EXPR;
}
if (binfo == error_mark_node)
return error_mark_node;
if (binfo && ! TREE_VIA_VIRTUAL (binfo))
expr = size_binop (code, expr, BINFO_OFFSET (binfo));
}
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;
}
rval = build1 (NOP_EXPR, type, expr);
TREE_CONSTANT (rval) = TREE_CONSTANT (expr);
return rval;
}
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);
}
if (type_unknown_p (expr))
return instantiate_type (type, expr, 1);
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)
tree type, arg;
int flags;
{
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);
TREE_SIDE_EFFECTS (arg) = 1;
}
/* 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 (rval == error_mark_node)
return error_mark_node;
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 (type) == FUNCTION_TYPE && intype == unknown_type_node)
{
expr = instantiate_type (type, expr, 0);
intype = TREE_TYPE (expr);
}
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. */
rval_as_conversion
= build_type_conversion (CONVERT_EXPR, reftype, 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 = lvalue_type (expr);
/* [dcl.init.ref] says that if an rvalue is used to
initialize a reference, then the reference must be to a
non-volatile const type. */
if (! real_lvalue_p (expr)
&& !CP_TYPE_CONST_NON_VOLATILE_P (ttl))
{
char* msg;
if (CP_TYPE_VOLATILE_P (ttl) && decl)
msg = "initialization of volatile reference type `%#T'";
else if (CP_TYPE_VOLATILE_P (ttl))
msg = "conversion to volatile reference type `%#T'";
else if (decl)
msg = "initialization of non-const reference type `%#T'";
else
msg = "conversion to non-const reference type `%#T'";
cp_error (msg, reftype);
cp_error ("from rvalue of type `%T'", intype);
}
else if (! (convtype & CONV_CONST)
&& !at_least_as_qualified_p (ttl, ttr))
cp_error ("conversion from `%T' to `%T' discards qualifiers",
ttr, reftype);
}
return build_up_reference (reftype, expr, flags);
}
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,
COMPARE_BASE | COMPARE_RELAXED )))
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
{
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);
if (rval && ! CP_TYPE_CONST_P (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;
}
/* 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 (intype == error_mark_node)
return error_mark_node;
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_qualified_type (type,
CP_TYPE_QUALS (TREE_TYPE (intype)));
ptr_type = build_pointer_type (ptr_type);
if (ptr_type == TYPE_MAIN_VARIANT (intype))
return expr;
my_friendly_assert (!integer_zerop (expr), 191);
intype = TYPE_MAIN_VARIANT (TREE_TYPE (intype));
if (TREE_CODE (type) == RECORD_TYPE
&& TREE_CODE (intype) == RECORD_TYPE
&& type != intype)
{
tree path;
int distance
= get_base_distance (binfo, 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'",
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 (TREE_READONLY_DECL_P (e))
e = decl_constant_value (e);
if (IS_AGGR_TYPE (type) && (convtype & CONV_FORCE_TEMP)
/* Some internal structures (vtable_entry_type, sigtbl_ptr_type)
don't go through finish_struct, so they don't have the synthesized
constructors. So don't force a temporary. */
&& TYPE_HAS_CONSTRUCTOR (type))
/* We need a new temporary; don't take this shortcut. */;
else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (e)))
{
if (same_type_p (type, TREE_TYPE (e)))
/* The call to fold will not always remove the NOP_EXPR as
might be expected, since if one of the types is a typedef;
the comparsion in fold is just equality of pointers, not a
call to comptypes. We don't call fold in this case because
that can result in infinite recursion; fold will call
convert, which will call ocp_convert, etc. */
return e;
else
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 (INTEGRAL_CODE_P (code))
{
tree intype = TREE_TYPE (e);
/* enum = enum, enum = int, enum = float, (enum)pointer are all
errors. */
if (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;
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. */
ctor = e;
if ((flags & LOOKUP_ONLYCONVERTING)
&& ! (IS_AGGR_TYPE (dtype) && DERIVED_FROM_P (type, dtype)))
/* For copy-initialization, first we create a temp of the proper type
with a user-defined conversion sequence, then we direct-initialize
the target with the temp (see [dcl.init]). */
ctor = build_user_type_conversion (type, ctor, flags);
if (ctor)
ctor = build_method_call (NULL_TREE, ctor_identifier,
build_expr_list (NULL_TREE, ctor),
TYPE_BINFO (type), flags);
if (ctor)
return build_cplus_new (type, ctor);
}
/* If TYPE or TREE_TYPE (E) is not on the permanent_obstack,
then 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);
}
/* 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 ATTRIBUTE_UNUSED;
tree xtype, expr;
int for_sure;
{
/* C++: check to see if we can convert this aggregate type
into the required type. */
return build_user_type_conversion
(xtype, expr, for_sure ? LOOKUP_NORMAL : 0);
}
/* 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 = NULL_TREE;
tree winner = NULL_TREE;
if (expr == null_node
&& (desires & WANT_INT)
&& !(desires & WANT_NULL))
cp_warning ("converting NULL to non-pointer type");
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) && null_ptr_cst_p (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;
}
/* The code for conversions from class type is currently only used for
delete expressions. Other expressions are handled by build_new_op. */
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;
default:
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_user_type_conversion (type, expr, LOOKUP_NORMAL);
}
return NULL_TREE;
}
/* Implements integral promotion (4.1) and float->double promotion. */
tree
type_promotes_to (type)
tree type;
{
int type_quals;
if (type == error_mark_node)
return error_mark_node;
type_quals = CP_TYPE_QUALS (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_qualified_type (type, type_quals);
}
/* The routines below this point are carefully written to conform to
the standard. They use the same terminology, and follow the rules
closely. Although they are used only in pt.c at the moment, they
should presumably be used everywhere in the future. */
/* Attempt to perform qualification conversions on EXPR to convert it
to TYPE. Return the resulting expression, or error_mark_node if
the conversion was impossible. */
tree
perform_qualification_conversions (type, expr)
tree type;
tree expr;
{
if (TREE_CODE (type) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE
&& comp_ptr_ttypes (TREE_TYPE (type), TREE_TYPE (TREE_TYPE (expr))))
return build1 (NOP_EXPR, type, expr);
else
return error_mark_node;
}