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re PR c/25801 (bad diagnostic for increment/decrement of pointer to incomplete array)

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PR c/25801
	* c-typeck.c (c_size_in_bytes): Update comment.  Don't call error.
	Return size_one_node when the type is not complete.
	(pointer_diff): Remove comment.
	(build_unary_op): Improve error messages.

	* gcc.dg/pr25801.c: New test.

From-SVN: r210013
This commit is contained in:
Marek Polacek 2014-05-02 18:13:43 +00:00 • committed by Marek Polacek
parent 19fc9faaaf
commit a0e24419cf
4 changed files with 68 additions and 12 deletions
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8
gcc/c/ChangeLog
View file

@ -1,3 +1,11 @@
2014-05-02 Marek Polacek <polacek@redhat.com>
PR c/25801
* c-typeck.c (c_size_in_bytes): Update comment. Don't call error.
Return size_one_node when the type is not complete.
(pointer_diff): Remove comment.
(build_unary_op): Improve error messages.
2014-05-02 Marek Polacek <polacek@redhat.com>
* c-typeck.c (c_finish_return): Separate warning_at calls.

23
gcc/c/c-typeck.c
View file

@ -1754,22 +1754,20 @@ type_lists_compatible_p (const_tree args1, const_tree args2,
}
}
/* Compute the size to increment a pointer by. */
/* Compute the size to increment a pointer by. When a function type or void
type or incomplete type is passed, size_one_node is returned.
This function does not emit any diagnostics; the caller is responsible
for that. */
static tree
c_size_in_bytes (const_tree type)
{
enum tree_code code = TREE_CODE (type);
if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK)
if (code == FUNCTION_TYPE || code == VOID_TYPE || code == ERROR_MARK
|| !COMPLETE_TYPE_P (type))
return size_one_node;
if (!COMPLETE_OR_VOID_TYPE_P (type))
{
error ("arithmetic on pointer to an incomplete type");
return size_one_node;
}
/* Convert in case a char is more than one unit. */
return size_binop_loc (input_location, CEIL_DIV_EXPR, TYPE_SIZE_UNIT (type),
size_int (TYPE_PRECISION (char_type_node)
@ -3530,7 +3528,6 @@ pointer_diff (location_t loc, tree op0, tree op1)
if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (TREE_TYPE (orig_op1))))
error_at (loc, "arithmetic on pointer to an incomplete type");
/* This generates an error if op0 is pointer to incomplete type. */
op1 = c_size_in_bytes (target_type);
if (pointer_to_zero_sized_aggr_p (TREE_TYPE (orig_op1)))
@ -4004,16 +4001,18 @@ build_unary_op (location_t location,
if (typecode == POINTER_TYPE)
{
/* If pointer target is an undefined struct,
/* If pointer target is an incomplete type,
we just cannot know how to do the arithmetic. */
if (!COMPLETE_OR_VOID_TYPE_P (TREE_TYPE (argtype)))
{
if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
error_at (location,
"increment of pointer to unknown structure");
"increment of pointer to an incomplete type %qT",
TREE_TYPE (argtype));
else
error_at (location,
"decrement of pointer to unknown structure");
"decrement of pointer to an incomplete type %qT",
TREE_TYPE (argtype));
}
else if (TREE_CODE (TREE_TYPE (argtype)) == FUNCTION_TYPE
|| TREE_CODE (TREE_TYPE (argtype)) == VOID_TYPE)

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2014-05-02 Marek Polacek <polacek@redhat.com>
PR c/25801
* gcc.dg/pr25801.c: New test.
2014-05-02 Marek Polacek <polacek@redhat.com>
PR c/60784

44
gcc/testsuite/gcc.dg/pr25801.c Normal file
View file

@ -0,0 +1,44 @@
/* PR c/25801 */
/* { dg-do compile } */
/* { dg-options "-std=c99" } */
int (*a)[];
struct S *s;
union U *u;
enum E *e;
void
f (void)
{
a++; /* { dg-error "increment of pointer to an incomplete type" } */
++a; /* { dg-error "increment of pointer to an incomplete type" } */
a--; /* { dg-error "decrement of pointer to an incomplete type" } */
--a; /* { dg-error "decrement of pointer to an incomplete type" } */
a += 1; /* { dg-error "invalid use of array with unspecified bounds" } */
a -= 1; /* { dg-error "invalid use of array with unspecified bounds" } */
a - a; /* { dg-error "arithmetic on pointer to an incomplete type" } */
s++; /* { dg-error "increment of pointer to an incomplete type" } */
++s; /* { dg-error "increment of pointer to an incomplete type" } */
s--; /* { dg-error "decrement of pointer to an incomplete type" } */
--s; /* { dg-error "decrement of pointer to an incomplete type" } */
s += 1; /* { dg-error "invalid use of undefined type" } */
s -= 1; /* { dg-error "invalid use of undefined type" } */
s - s; /* { dg-error "arithmetic on pointer to an incomplete type" } */
u++; /* { dg-error "increment of pointer to an incomplete type" } */
++u; /* { dg-error "increment of pointer to an incomplete type" } */
u--; /* { dg-error "decrement of pointer to an incomplete type" } */
--u; /* { dg-error "decrement of pointer to an incomplete type" } */
u += 1; /* { dg-error "invalid use of undefined type" } */
u -= 1; /* { dg-error "invalid use of undefined type" } */
u - u; /* { dg-error "arithmetic on pointer to an incomplete type" } */
e++; /* { dg-error "increment of pointer to an incomplete type" } */
++e; /* { dg-error "increment of pointer to an incomplete type" } */
e--; /* { dg-error "decrement of pointer to an incomplete type" } */
--e; /* { dg-error "decrement of pointer to an incomplete type" } */
e += 1; /* { dg-error "invalid use of undefined type" } */
e -= 1; /* { dg-error "invalid use of undefined type" } */
e - e; /* { dg-error "arithmetic on pointer to an incomplete type" } */
}