/* Language-level data type conversion for GNU C.
- Copyright (C) 1987, 1988, 1991 Free Software Foundation, Inc.
+ Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005, 2007
+ Free Software Foundation, Inc.
-This file is part of GNU CC.
+This file is part of GCC.
-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.
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
-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.
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
You should have received a copy of the GNU General Public License
-along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
/* This file contains the functions for converting C expressions
but what kind of conversions it does will depend on the language. */
#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
#include "tree.h"
#include "flags.h"
+#include "convert.h"
+#include "c-common.h"
+#include "c-tree.h"
+#include "langhooks.h"
+#include "toplev.h"
+#include "target.h"
/* Change of width--truncation and extension of integers or reals--
is represented with NOP_EXPR. Proper functioning of many things
Here is a list of all the functions that assume that widening and
narrowing is always done with a NOP_EXPR:
- In c-convert.c, convert_to_integer.
- In c-typeck.c, build_binary_op (boolean ops), and truthvalue_conversion.
+ In convert.c, convert_to_integer.
+ In c-typeck.c, build_binary_op (boolean ops), and
+ c_common_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. */
\f
/* Subroutines of `convert'. */
-static tree
-convert_to_pointer (type, expr)
- tree type, expr;
-{
- register tree intype = TREE_TYPE (expr);
- register enum tree_code form = TREE_CODE (intype);
-
- if (integer_zerop (expr))
- {
- if (type == TREE_TYPE (null_pointer_node))
- return null_pointer_node;
- expr = build_int_2 (0, 0);
- TREE_TYPE (expr) = type;
- return expr;
- }
-
- if (form == POINTER_TYPE)
- return build1 (NOP_EXPR, type, expr);
-
-
- if (form == INTEGER_TYPE || form == ENUMERAL_TYPE)
- {
- if (type_precision (intype) == POINTER_SIZE)
- return build1 (CONVERT_EXPR, type, expr);
- expr = convert (type_for_size (POINTER_SIZE, 0), expr);
- if (TYPE_MODE (TREE_TYPE (expr)) != 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);
- }
-
- error ("cannot convert to a pointer type");
-
- return null_pointer_node;
-}
-
-static tree
-convert_to_real (type, expr)
- tree type, expr;
-{
- register enum tree_code form = TREE_CODE (TREE_TYPE (expr));
-
- if (form == REAL_TYPE)
- return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
- type, expr);
-
- if (form == INTEGER_TYPE || form == ENUMERAL_TYPE)
- return build1 (FLOAT_EXPR, type, expr);
-
- if (form == POINTER_TYPE)
- error ("pointer value used where a float was expected");
- else
- error ("aggregate value used where a float was expected");
-
- {
- register tree tem = make_node (REAL_CST);
- TREE_TYPE (tem) = type;
- TREE_REAL_CST (tem) = REAL_VALUE_ATOF ("0.0");
- return tem;
- }
-}
-\f
-/* The result of this is always supposed to be a newly created tree node
- not in use in any existing structure. */
-
-static tree
-convert_to_integer (type, expr)
- tree type, expr;
-{
- register tree intype = TREE_TYPE (expr);
- register enum tree_code form = TREE_CODE (intype);
-
- if (form == POINTER_TYPE)
- {
- if (integer_zerop (expr))
- expr = integer_zero_node;
- else
- expr = fold (build1 (CONVERT_EXPR,
- type_for_size (POINTER_SIZE, 0), expr));
- intype = TREE_TYPE (expr);
- form = TREE_CODE (intype);
- if (intype == type)
- return expr;
- }
-
- if (form == INTEGER_TYPE || form == ENUMERAL_TYPE)
- {
- register unsigned outprec = TYPE_PRECISION (type);
- register unsigned inprec = TYPE_PRECISION (intype);
- register enum tree_code ex_form = TREE_CODE (expr);
-
- if (outprec >= inprec)
- return build1 (NOP_EXPR, type, expr);
-
-/* Here detect when we can distribute the truncation down past some arithmetic.
- For example, if adding two longs and converting to an int,
- we can equally well convert both to ints and then add.
- For the operations handled here, such truncation distribution
- is always safe.
- It is desirable in these cases:
- 1) when truncating down to full-word from a larger size
- 2) when truncating takes no work.
- 3) when at least one operand of the arithmetic has been extended
- (as by C's default conversions). In this case we need two conversions
- if we do the arithmetic as already requested, so we might as well
- truncate both and then combine. Perhaps that way we need only one.
-
- Note that in general we cannot do the arithmetic in a type
- shorter than the desired result of conversion, even if the operands
- are both extended from a shorter type, because they might overflow
- if combined in that type. The exceptions to this--the times when
- two narrow values can be combined in their narrow type even to
- make a wider result--are handled by "shorten" in build_binary_op. */
- switch (ex_form)
- {
- case RSHIFT_EXPR:
- /* We can pass truncation down through right shifting
- when the shift count is a negative constant. */
- if (TREE_CODE (TREE_OPERAND (expr, 1)) != INTEGER_CST
- || TREE_INT_CST_LOW (TREE_OPERAND (expr, 1)) > 0)
- break;
- goto trunc1;
-
- case LSHIFT_EXPR:
- /* We can pass truncation down through left shifting
- when the shift count is a positive constant. */
- if (TREE_CODE (TREE_OPERAND (expr, 1)) != INTEGER_CST
- || TREE_INT_CST_LOW (TREE_OPERAND (expr, 1)) < 0)
- break;
- /* In this case, shifting is like multiplication. */
- goto trunc1;
-
- case MAX_EXPR:
- case MIN_EXPR:
- case MULT_EXPR:
- {
- tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
- tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
-
- /* Don't distribute unless the output precision is at least as big
- as the actual inputs. Otherwise, the comparison of the
- truncated values will be wrong. */
- if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
- && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
- /* If signedness of arg0 and arg1 don't match,
- we can't necessarily find a type to compare them in. */
- && (TREE_UNSIGNED (TREE_TYPE (arg0))
- == TREE_UNSIGNED (TREE_TYPE (arg1))))
- goto trunc1;
- break;
- }
-
- case PLUS_EXPR:
- case MINUS_EXPR:
- case BIT_AND_EXPR:
- case BIT_IOR_EXPR:
- case BIT_XOR_EXPR:
- case BIT_ANDTC_EXPR:
- trunc1:
- {
- tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
- tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
-
- if (outprec >= BITS_PER_WORD
- || TRULY_NOOP_TRUNCATION (outprec, inprec)
- || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
- || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
- {
- /* Do the arithmetic in type TYPEX,
- then convert result to TYPE. */
- register tree typex = type;
-
- /* Can't do arithmetic in enumeral types
- so use an integer type that will hold the values. */
- if (TREE_CODE (typex) == ENUMERAL_TYPE)
- typex = type_for_size (TYPE_PRECISION (typex),
- TREE_UNSIGNED (typex));
-
- /* But now perhaps TYPEX is as wide as INPREC.
- In that case, do nothing special here.
- (Otherwise would recurse infinitely in convert. */
- if (TYPE_PRECISION (typex) != inprec)
- {
- /* Don't do unsigned arithmetic where signed was wanted,
- or vice versa.
- Exception: if either of the original operands were
- unsigned then can safely do the work as unsigned.
- And we may need to do it as unsigned
- if we truncate to the original size. */
- typex = ((TREE_UNSIGNED (TREE_TYPE (expr))
- || TREE_UNSIGNED (TREE_TYPE (arg0))
- || TREE_UNSIGNED (TREE_TYPE (arg1)))
- ? unsigned_type (typex) : signed_type (typex));
- return convert (type,
- build_binary_op (ex_form,
- convert (typex, arg0),
- convert (typex, arg1),
- 0));
- }
- }
- }
- break;
-
- case EQ_EXPR:
- case NE_EXPR:
- case GT_EXPR:
- case GE_EXPR:
- case LT_EXPR:
- case LE_EXPR:
- case TRUTH_AND_EXPR:
- case TRUTH_ANDIF_EXPR:
- case TRUTH_OR_EXPR:
- case TRUTH_ORIF_EXPR:
- case TRUTH_NOT_EXPR:
- /* If we want result of comparison converted to a byte,
- we can just regard it as a byte, since it is 0 or 1. */
- TREE_TYPE (expr) = type;
- return expr;
-
- case NEGATE_EXPR:
- case BIT_NOT_EXPR:
- {
- register tree typex = type;
-
- /* Can't do arithmetic in enumeral types
- so use an integer type that will hold the values. */
- if (TREE_CODE (typex) == ENUMERAL_TYPE)
- typex = type_for_size (TYPE_PRECISION (typex),
- TREE_UNSIGNED (typex));
-
- /* But now perhaps TYPEX is as wide as INPREC.
- In that case, do nothing special here.
- (Otherwise would recurse infinitely in convert. */
- if (TYPE_PRECISION (typex) != inprec)
- {
- /* Don't do unsigned arithmetic where signed was wanted,
- or vice versa. */
- typex = (TREE_UNSIGNED (TREE_TYPE (expr))
- ? unsigned_type (typex) : signed_type (typex));
- return convert (type,
- build_unary_op (ex_form,
- convert (typex, TREE_OPERAND (expr, 0)),
- 1));
- }
- }
-
- case NOP_EXPR:
- /* If truncating after truncating, might as well do all at once.
- If truncating after extending, we may get rid of wasted work. */
- return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
-
- case COND_EXPR:
- /* Can treat the two alternative values like the operands
- of an arithmetic expression. */
- {
- tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
- tree arg2 = get_unwidened (TREE_OPERAND (expr, 2), type);
-
- if (outprec >= BITS_PER_WORD
- || TRULY_NOOP_TRUNCATION (outprec, inprec)
- || inprec > TYPE_PRECISION (TREE_TYPE (arg1))
- || inprec > TYPE_PRECISION (TREE_TYPE (arg2)))
- {
- /* Do the arithmetic in type TYPEX,
- then convert result to TYPE. */
- register tree typex = type;
-
- /* Can't do arithmetic in enumeral types
- so use an integer type that will hold the values. */
- if (TREE_CODE (typex) == ENUMERAL_TYPE)
- typex = type_for_size (TYPE_PRECISION (typex),
- TREE_UNSIGNED (typex));
-
- /* But now perhaps TYPEX is as wide as INPREC.
- In that case, do nothing special here.
- (Otherwise would recurse infinitely in convert. */
- if (TYPE_PRECISION (typex) != inprec)
- {
- /* Don't do unsigned arithmetic where signed was wanted,
- or vice versa. */
- typex = (TREE_UNSIGNED (TREE_TYPE (expr))
- ? unsigned_type (typex) : signed_type (typex));
- return convert (type,
- fold (build (COND_EXPR, typex,
- TREE_OPERAND (expr, 0),
- convert (typex, arg1),
- convert (typex, arg2))));
- }
- else
- /* It is sometimes worthwhile
- to push the narrowing down through the conditional. */
- return fold (build (COND_EXPR, type,
- TREE_OPERAND (expr, 0),
- convert (type, TREE_OPERAND (expr, 1)),
- convert (type, TREE_OPERAND (expr, 2))));
- }
- }
- }
-
- return build1 (NOP_EXPR, type, expr);
- }
-
- if (form == REAL_TYPE)
- return build1 (FIX_TRUNC_EXPR, type, expr);
-
- error ("aggregate value used where an integer was expected");
-
- {
- register tree tem = build_int_2 (0, 0);
- TREE_TYPE (tem) = type;
- return tem;
- }
-}
\f
/* Create an expression whose value is that of EXPR,
converted to type TYPE. The TREE_TYPE of the value
not permitted by the language being compiled. */
tree
-convert (type, expr)
- tree type, expr;
+convert (tree type, tree expr)
{
- register tree e = expr;
- register enum tree_code code = TREE_CODE (type);
+ tree e = expr;
+ enum tree_code code = TREE_CODE (type);
+ const char *invalid_conv_diag;
- if (type == TREE_TYPE (expr) || TREE_CODE (expr) == ERROR_MARK)
+ if (type == error_mark_node
+ || expr == error_mark_node
+ || TREE_TYPE (expr) == error_mark_node)
+ return error_mark_node;
+
+ if ((invalid_conv_diag
+ = targetm.invalid_conversion (TREE_TYPE (expr), type)))
+ {
+ error (invalid_conv_diag);
+ return error_mark_node;
+ }
+
+ if (type == TREE_TYPE (expr))
return expr;
+
+ if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
+ return fold_convert (type, expr);
if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK)
return error_mark_node;
if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE)
return error_mark_node;
}
if (code == VOID_TYPE)
- 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 (expr) == NOP_EXPR)
- return convert (type, TREE_OPERAND (expr, 0));
-#endif
+ return fold_convert (type, e);
if (code == INTEGER_TYPE || code == ENUMERAL_TYPE)
return fold (convert_to_integer (type, e));
- if (code == POINTER_TYPE)
+ if (code == BOOLEAN_TYPE)
+ return fold_convert (type, c_objc_common_truthvalue_conversion (expr));
+ if (code == POINTER_TYPE || code == REFERENCE_TYPE)
return fold (convert_to_pointer (type, e));
if (code == REAL_TYPE)
return fold (convert_to_real (type, e));
+ if (code == FIXED_POINT_TYPE)
+ return fold (convert_to_fixed (type, e));
+ if (code == COMPLEX_TYPE)
+ return fold (convert_to_complex (type, e));
+ if (code == VECTOR_TYPE)
+ return fold (convert_to_vector (type, e));
+ if ((code == RECORD_TYPE || code == UNION_TYPE)
+ && lang_hooks.types_compatible_p (type, TREE_TYPE (expr)))
+ return e;
error ("conversion to non-scalar type requested");
return error_mark_node;
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