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support: Increase usability of TEST_COMPARE 

The previous implementation of the TEST_COMPARE macro would fail
to compile code like this:

  int ret = res_send (query, sizeof (query), buf, sizeof (buf));
  TEST_COMPARE (ret,
                sizeof (query)
                + 2             /* Compression reference.  */
                + 2 + 2 + 4 + 2 /* Type, class, TTL, RDATA length.  */
                + 1             /* Pascal-style string length.  */
                + strlen (expected_name));

This resulted in a failed static assertion, "integer conversions
may alter sign of operands".  A user of the TEST_COMPARE would have
to add a cast to fix this.

This patch reverts to the original proposed solution of a run-time
check, making TEST_COMPARE usable for comparisons of numbers with
types with different signedness in more contexts.
This commit is contained in:
Florian Weimer 2018-01-08 13:01:36 +01:00
parent 630f4cc3aa
commit 2b3aa44656
4 changed files with 49 additions and 32 deletions
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12
ChangeLog
View File

@ -1,3 +1,15 @@
2018-01-08 Florian Weimer <fweimer@redhat.com>
* support/check.h (TEST_COMPARE): Allow sign mismatch at compile
time. Pass positive flag instead of negative flag to
support_test_compare_failure.
(support_test_compare_failure): Change negative parameter to
positive.
* support/support_test_compare_failure.c (report)
(support_test_compare_failure): Likewise.
* support/tst-test_compare.c (return_ssize_t, return_int): New.
(do_test): Check int/size_t, ssize_t/size_t comparisons.
2018-01-08 Szabolcs Nagy <szabolcs.nagy@arm.com>
[BZ #22637]

35
support/check.h
View File

@ -102,7 +102,9 @@ void support_record_failure (void);
typedef __typeof__ (+ (right)) __right_type; \
__left_type __left_value = (left); \
__right_type __right_value = (right); \
/* Prevent use with floating-point and boolean types. */ \
int __left_is_positive = __left_value > 0; \
int __right_is_positive = __right_value > 0; \
/* Prevent use with floating-point types. */ \
support_static_assert ((__left_type) 1.0 == (__left_type) 1.5, \
"left value has floating-point type"); \
support_static_assert ((__right_type) 1.0 == (__right_type) 1.5, \
@ -112,33 +114,18 @@ void support_record_failure (void);
"left value fits into long long"); \
support_static_assert (sizeof (__right_value) <= sizeof (long long), \
"right value fits into long long"); \
/* Make sure that integer conversions does not alter the sign. */ \
enum \
{ \
__left_is_unsigned = (__left_type) -1 > 0, \
__right_is_unsigned = (__right_type) -1 > 0, \
__unsigned_left_converts_to_wider = (__left_is_unsigned \
&& (sizeof (__left_value) \
< sizeof (__right_value))), \
__unsigned_right_converts_to_wider = (__right_is_unsigned \
&& (sizeof (__right_value) \
< sizeof (__left_value))) \
}; \
support_static_assert (__left_is_unsigned == __right_is_unsigned \
|| __unsigned_left_converts_to_wider \
|| __unsigned_right_converts_to_wider, \
"integer conversions may alter sign of operands"); \
/* Compare the value. */ \
if (__left_value != __right_value) \
if (__left_value != __right_value \
|| __left_is_positive != __right_is_positive) \
/* Pass the sign for printing the correct value. */ \
support_test_compare_failure \
(__FILE__, __LINE__, \
#left, __left_value, __left_value < 0, sizeof (__left_type), \
#right, __right_value, __right_value < 0, sizeof (__right_type)); \
#left, __left_value, __left_is_positive, sizeof (__left_type), \
#right, __right_value, __right_is_positive, sizeof (__right_type)); \
})
/* Internal implementation of TEST_COMPARE. LEFT_NEGATIVE and
RIGHT_NEGATIVE are used to store the sign separately, so that both
/* Internal implementation of TEST_COMPARE. LEFT_POSITIVE and
RIGHT_POSITIVE are used to store the sign separately, so that both
unsigned long long and long long arguments fit into LEFT_VALUE and
RIGHT_VALUE, and the function can still print the original value.
LEFT_SIZE and RIGHT_SIZE specify the size of the argument in bytes,
@ -146,11 +133,11 @@ void support_record_failure (void);
void support_test_compare_failure (const char *file, int line,
const char *left_expr,
long long left_value,
int left_negative,
int left_positive,
int left_size,
const char *right_expr,
long long right_value,
int right_negative,
int right_positive,
int right_size);

16
support/support_test_compare_failure.c
View File

@ -20,14 +20,14 @@
#include <support/check.h>
static void
report (const char *which, const char *expr, long long value, int negative,
report (const char *which, const char *expr, long long value, int positive,
int size)
{
printf (" %s: ", which);
if (negative)
printf ("%lld", value);
else
if (positive)
printf ("%llu", (unsigned long long) value);
else
printf ("%lld", value);
unsigned long long mask
= (~0ULL) >> (8 * (sizeof (unsigned long long) - size));
printf (" (0x%llx); from: %s\n", (unsigned long long) value & mask, expr);
@ -37,11 +37,11 @@ void
support_test_compare_failure (const char *file, int line,
const char *left_expr,
long long left_value,
int left_negative,
int left_positive,
int left_size,
const char *right_expr,
long long right_value,
int right_negative,
int right_positive,
int right_size)
{
support_record_failure ();
@ -50,6 +50,6 @@ support_test_compare_failure (const char *file, int line,
file, line, left_size * 8, right_size * 8);
else
printf ("%s:%d: numeric comparison failure\n", file, line);
report (" left", left_expr, left_value, left_negative, left_size);
report ("right", right_expr, right_value, right_negative, right_size);
report (" left", left_expr, left_value, left_positive, left_size);
report ("right", right_expr, right_value, right_positive, right_size);
}

18
support/tst-test_compare.c
View File

@ -42,6 +42,22 @@ struct bitfield
unsigned long long int u63 : 63;
};
/* Functions which return signed sizes are common, so test that these
results can readily checked using TEST_COMPARE. */
static int
return_ssize_t (void)
{
return 4;
}
static int
return_int (void)
{
return 4;
}
static int
do_test (void)
{
@ -53,6 +69,8 @@ do_test (void)
unsigned short u16 = 3;
TEST_COMPARE (i8, u16);
}
TEST_COMPARE (return_ssize_t (), sizeof (char[4]));
TEST_COMPARE (return_int (), sizeof (char[4]));
struct bitfield bitfield = { 0 };
TEST_COMPARE (bitfield.i2, bitfield.i3);