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c-common.c (c_common_truthvalue_conversion): Warn if the address of a non-weak function is used as a truth value.

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gcc/
	* c-common.c (c_common_truthvalue_conversion): Warn if the
	address of a non-weak function is used as a truth value.

cp/
	* cvt.c (ocp_convert): Move warning to C common code.

testsuite/
	* gcc.dg/weak/weak-3.c: Fix for new warning.

From-SVN: r72409
This commit is contained in:
Steven Bosscher 2003-10-12 22:09:29 +00:00
parent d60004eecf
commit 1998463c54
6 changed files with 40 additions and 24 deletions
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5
gcc/ChangeLog
View File

@ -1,3 +1,8 @@
2003-10-12 Steven Bosscher <steven@gcc.gnu.org>
* c-common.c (c_common_truthvalue_conversion): Warn if the
address of a non-weak function is used as a truth value.
2003-10-12 Kazu Hirata <kazu@cs.umass.edu>
* config/h8300/h8300.c (WORD_REG_USED): Use SP_REG instead of

35
gcc/c-common.c
View File

@ -2602,6 +2602,9 @@ c_common_truthvalue_conversion (tree expr)
if (TREE_CODE (expr) == ERROR_MARK)
return expr;
if (TREE_CODE (expr) == FUNCTION_DECL)
expr = build_unary_op (ADDR_EXPR, expr, 0);
#if 0 /* This appears to be wrong for C++. */
/* These really should return error_mark_node after 2.4 is stable.
But not all callers handle ERROR_MARK properly. */
@ -2647,17 +2650,29 @@ c_common_truthvalue_conversion (tree expr)
return real_zerop (expr) ? truthvalue_false_node : truthvalue_true_node;
case ADDR_EXPR:
/* If we are taking the address of an external decl, it might be zero
if it is weak, so we cannot optimize. */
if (DECL_P (TREE_OPERAND (expr, 0))
&& DECL_EXTERNAL (TREE_OPERAND (expr, 0)))
break;
{
if (TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL
&& ! DECL_WEAK (TREE_OPERAND (expr, 0)))
{
/* Common Ada/Pascal programmer's mistake. We always warn
about this since it is so bad. */
warning ("the address of `%D', will always evaluate as `true'",
TREE_OPERAND (expr, 0));
return truthvalue_true_node;
}
if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
return build (COMPOUND_EXPR, truthvalue_type_node,
TREE_OPERAND (expr, 0), truthvalue_true_node);
else
return truthvalue_true_node;
/* If we are taking the address of an external decl, it might be
zero if it is weak, so we cannot optimize. */
if (DECL_P (TREE_OPERAND (expr, 0))
&& DECL_EXTERNAL (TREE_OPERAND (expr, 0)))
break;
if (TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 0)))
return build (COMPOUND_EXPR, truthvalue_type_node,
TREE_OPERAND (expr, 0), truthvalue_true_node);
else
return truthvalue_true_node;
}
case COMPLEX_EXPR:
return build_binary_op ((TREE_SIDE_EFFECTS (TREE_OPERAND (expr, 1))

4
gcc/cp/ChangeLog
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@ -1,3 +1,7 @@
2003-10-12 Steven Bosscher <steven@gcc.gnu.org>
* cvt.c (ocp_convert): Move warning to C common code.
2003-10-09 Jason Merrill <jason@redhat.com>
PR c++/6392

14
gcc/cp/cvt.c
View File

@ -694,20 +694,8 @@ ocp_convert (tree type, tree expr, int convtype, int flags)
return error_mark_node;
}
if (code == BOOLEAN_TYPE)
{
tree fn = NULL_TREE;
return cp_truthvalue_conversion (e);
/* Common Ada/Pascal programmer's mistake. We always warn
about this since it is so bad. */
if (TREE_CODE (expr) == FUNCTION_DECL)
fn = expr;
else if (TREE_CODE (expr) == ADDR_EXPR
&& TREE_CODE (TREE_OPERAND (expr, 0)) == FUNCTION_DECL)
fn = TREE_OPERAND (expr, 0);
if (fn && !DECL_WEAK (fn))
warning ("the address of `%D', will always be `true'", fn);
return cp_truthvalue_conversion (e);
}
return fold (convert_to_integer (type, e));
}
if (POINTER_TYPE_P (type) || TYPE_PTR_TO_MEMBER_P (type))

4
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2003-10-12 Steven Bosscher <steven@gcc.gnu.org>
* gcc.dg/weak/weak-3.c: Fix for new warning.
2003-10-12 Kelley Cook <kcook@gcc.gnu.org>
PR optimization/8750

2
gcc/testsuite/gcc.dg/weak/weak-3.c
View File

@ -54,7 +54,7 @@ extern void * ffoo1f (void);
extern void * ffoox1f (void);
void * foo1f (void)
{
if (ffoo1f)
if (ffoo1f) /* { dg-warning "" } */
ffoo1f ();
return 0;
}