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typeck.c (build_binary_op_nodefault): Warn on use of NULL in arithmetic.

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* typeck.c (build_binary_op_nodefault): Warn on use of NULL in
	arithmetic.
	* except.c (build_throw): Warn when NULL is thrown, even with
	-ansi.  Use ansi_null_node, rather than integer_zero_node, in the
	thrown expression.

From-SVN: r21863
This commit is contained in:
Mark Mitchell 1998-08-19 18:48:58 +00:00 committed by Mark Mitchell
parent 893779cc02
commit e0f9a8bc50
4 changed files with 33 additions and 14 deletions
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8
gcc/cp/ChangeLog
View File

@ -1,5 +1,11 @@
1998-08-19 Mark Mitchell <mark@markmitchell.com>
* typeck.c (build_binary_op_nodefault): Warn on use of NULL in
arithmetic.
* except.c (build_throw): Warn when NULL is thrown, even with
-ansi. Use ansi_null_node, rather than integer_zero_node, in the
thrown expression.
* cp-tree.h (ansi_null_node): New variable.
* decl.c (ansi_null_node): New variable.
(init_decl_processing): Initialize its type.
@ -7,7 +13,7 @@
for null_node in non-ANSI mode.
* typeck.c (build_binary_op_nodefault): Use ansi_null_node in
place of null_node to avoid spurious errors.
1998-08-17 Mark Mitchell <mark@markmitchell.com>
* cp-tree.h (enter_scope_of): New function.

6
gcc/cp/except.c
View File

@ -1277,10 +1277,10 @@ build_throw (e)
if (processing_template_decl)
return build_min (THROW_EXPR, void_type_node, e);
if (! flag_ansi && e == null_node)
if (e == null_node)
{
cp_warning ("throwing NULL");
e = integer_zero_node;
cp_warning ("throwing NULL, which has integral, not pointer type");
e = ansi_null_node;
}
e = build1 (THROW_EXPR, void_type_node, e);

29
gcc/cp/typeck.c
View File

@ -3248,23 +3248,21 @@ build_binary_op_nodefault (code, orig_op0, orig_op1, error_code)
things like `7 != NULL' result in errors about comparisons
between pointers and integers. So, here, we replace __null with
an appropriate null pointer constant. */
if (orig_op0 == null_node)
orig_op0 = ansi_null_node;
if (orig_op1 == null_node)
orig_op1 = ansi_null_node;
op0 = (orig_op0 == null_node) ? ansi_null_node : orig_op0;
op1 = (orig_op1 == null_node) ? ansi_null_node : orig_op1;
/* Apply default conversions. */
if (code == TRUTH_AND_EXPR || code == TRUTH_ANDIF_EXPR
|| code == TRUTH_OR_EXPR || code == TRUTH_ORIF_EXPR
|| code == TRUTH_XOR_EXPR)
{
op0 = decay_conversion (orig_op0);
op1 = decay_conversion (orig_op1);
op0 = decay_conversion (op0);
op1 = decay_conversion (op1);
}
else
{
op0 = default_conversion (orig_op0);
op1 = default_conversion (orig_op1);
op0 = default_conversion (op0);
op1 = default_conversion (op1);
}
type0 = TREE_TYPE (op0);
@ -3963,6 +3961,21 @@ build_binary_op_nodefault (code, orig_op0, orig_op1, error_code)
return error_mark_node;
}
if (/* If OP0 is NULL and OP1 is not a pointer, or vice versa. */
(orig_op0 == null_node
&& TREE_CODE (TREE_TYPE (orig_op1)) != POINTER_TYPE)
/* Or vice versa. */
|| (orig_op1 == null_node
&& TREE_CODE (TREE_TYPE (orig_op0)) != POINTER_TYPE)
/* Or, both are NULL and the operation was not a comparison. */
|| (orig_op0 == null_node && orig_op1 == null_node
&& code != EQ_EXPR && code != NE_EXPR))
/* Some sort of arithmetic operation involving NULL was
performed. Note that pointer-difference and pointer-addition
have already been handled above, and so we don't end up here in
that case. */
cp_warning ("NULL used in arithmetic");
if (! converted)
{
if (TREE_TYPE (op0) != result_type)

4
gcc/testsuite/g++.old-deja/g++.other/null1.C
View File

@ -7,6 +7,6 @@ void f()
int i;
float f;
i != NULL;
f != NULL;
i != NULL; // WARNING - NULL used in arithmetic
f != NULL; // WARNING - NULL used in arithmetic
}