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c-typeck.c (null_pointer_constant_p): New function.

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* c-typeck.c (null_pointer_constant_p): New function.
	(build_conditional_expr, build_c_cast, convert_for_assignment,
	build_binary_op): Use it.

testsuite:
	* gcc.dg/c90-const-expr-5.c, gcc.dg/c99-const-expr-5.c: New tests.

From-SVN: r108022
This commit is contained in:
Joseph Myers 2005-12-04 23:04:59 +00:00 committed by Joseph Myers
parent 1344f9a318
commit 6aa3c60d7f
5 changed files with 120 additions and 18 deletions
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6
gcc/ChangeLog
View File

@ -1,3 +1,9 @@
2005-12-04 Joseph S. Myers <joseph@codesourcery.com>
* c-typeck.c (null_pointer_constant_p): New function.
(build_conditional_expr, build_c_cast, convert_for_assignment,
build_binary_op): Use it.
2005-12-04 Joseph S. Myers <joseph@codesourcery.com>
* c-common.c (binary_op_error): Do not allow NOP_EXPR.

50
gcc/c-typeck.c
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@ -74,6 +74,7 @@ static int missing_braces_mentioned;
static int require_constant_value;
static int require_constant_elements;
static bool null_pointer_constant_p (tree);
static tree qualify_type (tree, tree);
static int tagged_types_tu_compatible_p (tree, tree);
static int comp_target_types (tree, tree);
@ -106,6 +107,23 @@ static int lvalue_or_else (tree, enum lvalue_use);
static int lvalue_p (tree);
static void record_maybe_used_decl (tree);
static int comptypes_internal (tree, tree);
/* Return true if EXP is a null pointer constant, false otherwise. */
static bool
null_pointer_constant_p (tree expr)
{
/* This should really operate on c_expr structures, but they aren't
yet available everywhere required. */
tree type = TREE_TYPE (expr);
return (TREE_CODE (expr) == INTEGER_CST
&& !TREE_CONSTANT_OVERFLOW (expr)
&& integer_zerop (expr)
&& (INTEGRAL_TYPE_P (type)
|| (TREE_CODE (type) == POINTER_TYPE
&& VOID_TYPE_P (TREE_TYPE (type))
&& TYPE_QUALS (TREE_TYPE (type)) == TYPE_UNQUALIFIED)));
}
/* This is a cache to hold if two types are compatible or not. */
struct tagged_tu_seen_cache {
@ -3205,9 +3223,9 @@ build_conditional_expr (tree ifexp, tree op1, tree op2)
{
if (comp_target_types (type1, type2))
result_type = common_pointer_type (type1, type2);
else if (integer_zerop (orig_op1) && TREE_TYPE (type1) == void_type_node)
else if (null_pointer_constant_p (orig_op1))
result_type = qualify_type (type2, type1);
else if (integer_zerop (orig_op2) && TREE_TYPE (type2) == void_type_node)
else if (null_pointer_constant_p (orig_op2))
result_type = qualify_type (type1, type2);
else if (VOID_TYPE_P (TREE_TYPE (type1)))
{
@ -3233,7 +3251,7 @@ build_conditional_expr (tree ifexp, tree op1, tree op2)
}
else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
{
if (!integer_zerop (op2))
if (!null_pointer_constant_p (orig_op2))
pedwarn ("pointer/integer type mismatch in conditional expression");
else
{
@ -3243,7 +3261,7 @@ build_conditional_expr (tree ifexp, tree op1, tree op2)
}
else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
{
if (!integer_zerop (op1))
if (!null_pointer_constant_p (orig_op1))
pedwarn ("pointer/integer type mismatch in conditional expression");
else
{
@ -3481,7 +3499,7 @@ build_c_cast (tree type, tree expr)
&& TREE_CODE (otype) == POINTER_TYPE
&& TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE
&& TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
&& !(integer_zerop (value) && TREE_TYPE (otype) == void_type_node))
&& !null_pointer_constant_p (value))
pedwarn ("ISO C forbids conversion of object pointer to function pointer type");
ovalue = value;
@ -3834,7 +3852,7 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
}
/* Can convert integer zero to any pointer type. */
if (integer_zerop (rhs))
if (null_pointer_constant_p (rhs))
{
rhs = null_pointer_node;
break;
@ -3972,7 +3990,7 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
&& ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
||
(VOID_TYPE_P (ttr)
&& !integer_zerop (rhs)
&& !null_pointer_constant_p (rhs)
&& TREE_CODE (ttl) == FUNCTION_TYPE)))
WARN_FOR_ASSIGNMENT (G_("ISO C forbids passing argument %d of "
"%qE between function pointer "
@ -4062,7 +4080,7 @@ convert_for_assignment (tree type, tree rhs, enum impl_conv errtype,
/* An explicit constant 0 can convert to a pointer,
or one that results from arithmetic, even including
a cast to integer type. */
if (!integer_zerop (rhs))
if (!null_pointer_constant_p (rhs))
WARN_FOR_ASSIGNMENT (G_("passing argument %d of %qE makes "
"pointer from integer without a cast"),
G_("assignment makes pointer from integer "
@ -7900,14 +7918,14 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
{
/* op0 != orig_op0 detects the case of something
whose value is 0 but which isn't a valid null ptr const. */
if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
if (pedantic && !null_pointer_constant_p (orig_op0)
&& TREE_CODE (tt1) == FUNCTION_TYPE)
pedwarn ("ISO C forbids comparison of %<void *%>"
" with function pointer");
}
else if (VOID_TYPE_P (tt1))
{
if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
if (pedantic && !null_pointer_constant_p (orig_op1)
&& TREE_CODE (tt0) == FUNCTION_TYPE)
pedwarn ("ISO C forbids comparison of %<void *%>"
" with function pointer");
@ -7920,11 +7938,9 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
if (result_type == NULL_TREE)
result_type = ptr_type_node;
}
else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
&& integer_zerop (op1))
else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
result_type = type0;
else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
&& integer_zerop (op0))
else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
result_type = type1;
else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
{
@ -7964,15 +7980,13 @@ build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
pedwarn ("comparison of distinct pointer types lacks a cast");
}
}
else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
&& integer_zerop (op1))
else if (code0 == POINTER_TYPE && null_pointer_constant_p (orig_op1))
{
result_type = type0;
if (pedantic || extra_warnings)
pedwarn ("ordered comparison of pointer with integer zero");
}
else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
&& integer_zerop (op0))
else if (code1 == POINTER_TYPE && null_pointer_constant_p (orig_op0))
{
result_type = type1;
if (pedantic)

4
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2005-12-04 Joseph S. Myers <joseph@codesourcery.com>
* gcc.dg/c90-const-expr-5.c, gcc.dg/c99-const-expr-5.c: New tests.
2005-12-04 Joseph S. Myers <joseph@codesourcery.com>
* gcc.dg/format/cast-1.c: New test.

39
gcc/testsuite/gcc.dg/c90-const-expr-5.c Normal file
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@ -0,0 +1,39 @@
/* Test null pointer constants: typedefs for void should be OK but not
qualified void. */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
/* { dg-options "-std=iso9899:1990 -pedantic-errors" } */
typedef void V;
int *p;
long *q;
int j;
void (*fp)(void);
void
f (void)
{
/* (V *)0 is a null pointer constant, so the assignment should be
diagnosed. */
q = (j ? p : (V *)0); /* { dg-error "error: assignment from incompatible pointer type" } */
q = (j ? p : (void *)0); /* { dg-error "error: assignment from incompatible pointer type" } */
/* And this conversion should be valid. */
(void (*)(void))(V *)0;
(void (*)(void))(void *)0;
/* Pointers to qualified void are not valid null pointer
constants. */
fp = (const void *)0; /* { dg-error "error: ISO C forbids assignment between function pointer and 'void \\*'" } */
fp = (void *)0;
fp = (V *)0;
fp = 0;
fp == 0;
0 == fp;
fp == (void *)0;
(void *)0 == fp;
fp == (V *)0;
(V *)0 == fp;
fp == (V *)1; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
(V *)1 == fp; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
fp == (const void *)0; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
(const void *)0 == fp; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
}

39
gcc/testsuite/gcc.dg/c99-const-expr-5.c Normal file
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@ -0,0 +1,39 @@
/* Test null pointer constants: typedefs for void should be OK but not
qualified void. */
/* Origin: Joseph Myers <joseph@codesourcery.com> */
/* { dg-do compile } */
/* { dg-options "-std=iso9899:1999 -pedantic-errors" } */
typedef void V;
int *p;
long *q;
int j;
void (*fp)(void);
void
f (void)
{
/* (V *)0 is a null pointer constant, so the assignment should be
diagnosed. */
q = (j ? p : (V *)0); /* { dg-error "error: assignment from incompatible pointer type" } */
q = (j ? p : (void *)0); /* { dg-error "error: assignment from incompatible pointer type" } */
/* And this conversion should be valid. */
(void (*)(void))(V *)0;
(void (*)(void))(void *)0;
/* Pointers to qualified void are not valid null pointer
constants. */
fp = (const void *)0; /* { dg-error "error: ISO C forbids assignment between function pointer and 'void \\*'" } */
fp = (void *)0;
fp = (V *)0;
fp = 0;
fp == 0;
0 == fp;
fp == (void *)0;
(void *)0 == fp;
fp == (V *)0;
(V *)0 == fp;
fp == (V *)1; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
(V *)1 == fp; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
fp == (const void *)0; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
(const void *)0 == fp; /* { dg-error "error: ISO C forbids comparison of 'void \\*' with function pointer" } */
}