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re PR c/12818 (-fwritable strings triggers bad code generation)

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PR c/12818
	* varasm.c (const_hash_1) <STRING_CST>: Use the
	address to compute the hash value if flag_writable_strings.
	(compare_constant) <STRING_CST>: Compare the addresses
	if flag_writable_strings.
	(build_constant_desc): Do not copy the expression for a
	STRING_CST if flag_writable_strings.

From-SVN: r76958
This commit is contained in:
Eric Botcazou 2004-01-30 15:16:43 +01:00 committed by Eric Botcazou
parent 7dcc98e25c
commit 5e9295fa05
4 changed files with 49 additions and 6 deletions
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10
gcc/ChangeLog
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@ -1,3 +1,13 @@
2004-01-30 Eric Botcazou <ebotcazou@libertysurf.fr>
PR c/12818
* varasm.c (const_hash_1) <STRING_CST>: Use the
address to compute the hash value if flag_writable_strings.
(compare_constant) <STRING_CST>: Compare the addresses
if flag_writable_strings.
(build_constant_desc): Do not copy the expression for a
STRING_CST if flag_writable_strings.
2004-01-30 Jan Hubicka <jh@suse.cz>
* alloc-pool.c: Include hashtab.h

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2004-01-30 Eric Botcazou <ebotcazou@libertysurf.fr>
* gcc.dg/fwritable-strings-1.c: New test.
2004-01-30 Eric Botcazou <ebotcazou@libertysurf.fr>
* gcc.c-torture/compile/20040130-1.c: New test.

17
gcc/testsuite/gcc.dg/fwritable-strings-1.c Normal file
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@ -0,0 +1,17 @@
/* PR c/12818 */
/* Origin: <fnf@ninemoons.com> */
/* { dg-do run } */
/* { dg-options "-fwritable-strings" } */
extern void abort(void);
char *names[] = {"alice", "bob", "john"};
int main (void)
{
if (names[1][0] != 'b')
abort();
return 0;
}

24
gcc/varasm.c
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@ -2057,7 +2057,7 @@ struct rtx_const GTY(())
/* Uniquize all constants that appear in memory.
Each constant in memory thus far output is recorded
in `const_hash_table'. */
in `const_desc_table'. */
struct constant_descriptor_tree GTY(())
{
@ -2104,9 +2104,18 @@ const_hash_1 (const tree exp)
return real_hash (TREE_REAL_CST_PTR (exp));
case STRING_CST:
p = TREE_STRING_POINTER (exp);
len = TREE_STRING_LENGTH (exp);
if (flag_writable_strings)
{
p = (char *) &exp;
len = sizeof exp;
}
else
{
p = TREE_STRING_POINTER (exp);
len = TREE_STRING_LENGTH (exp);
}
break;
case COMPLEX_CST:
return (const_hash_1 (TREE_REALPART (exp)) * 5
+ const_hash_1 (TREE_IMAGPART (exp)));
@ -2221,7 +2230,7 @@ compare_constant (const tree t1, const tree t2)
case STRING_CST:
if (flag_writable_strings)
return 0;
return t1 == t2;
if (TYPE_MODE (TREE_TYPE (t1)) != TYPE_MODE (TREE_TYPE (t2)))
return 0;
@ -2425,7 +2434,10 @@ build_constant_desc (tree exp)
struct constant_descriptor_tree *desc;
desc = ggc_alloc (sizeof (*desc));
desc->value = copy_constant (exp);
if (flag_writable_strings && TREE_CODE (exp) == STRING_CST)
desc->value = exp;
else
desc->value = copy_constant (exp);
/* Create a string containing the label name, in LABEL. */
labelno = const_labelno++;
@ -2466,7 +2478,7 @@ build_constant_desc (tree exp)
If DEFER is nonzero, this constant can be deferred and output only
if referenced in the function after all optimizations.
The const_hash_table records which constants already have label strings. */
`const_desc_table' records which constants already have label strings. */
rtx
output_constant_def (tree exp, int defer)