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Bug 20729: Fix building with -Os.

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This commit adds a new DIAG_IGNORE_Os_NEEDS_COMMENT which is only
enabled when compiling with -Os. This allows developers working on
-Os enabled builds to mark false-positive warnings without impacting the
warnings emitted at -O2.

Then using the new DIAG_IGNORE_Os_NEEDS_COMMENT we fix 6 warnings
generated with GCC 5 to get -Os builds working again.
This commit is contained in:
Carlos O'Donell 2016-10-29 23:45:40 -04:00
parent 960294f00a
commit 93fe09cb5f
8 changed files with 91 additions and 1 deletions
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16
ChangeLog
View File

@ -1,5 +1,21 @@
2016-10-28 Carlos O'Donell <carlos@redhat.com>
[BZ #20729]
* include/libc-internal.h (DIAG_IGNORE_Os_NEEDS_COMMENT):
Define.
* iso-2022-cn-ext.c: Include libc-internal.h and ignore
-Wmaybe-uninitialized for BODY macro only for -Os compiles.
* locale/weight.h (findix): Ignore -Wmaybe-uninitialized error
for seq2.back_us and seq1.back_us only for -Os compiles.
* locale/weightwc.h (findix): Likewise.
* nptl_db/thread_dbP.h: Ignore -Wmaybe-uninitialized error for
DB_GET_FIELD_ADDRESS only for -Os compiles.
* resolv/res_send (reopen): Ignore -Wmaybe-uninitialized error
for slen only for -Os compiles.
* string/strcoll_l.c (get_next_seq): Ignore
-Wmaybe-uninitialized for seq2.save_idx and seq1.save_idx only
for -Os compiles.
* elf/Makefile (CFALGS-tst-linkall-static): Remove.
* include/crypt.h: New file.

12
iconvdata/iso-2022-cn-ext.c
View File

@ -27,6 +27,7 @@
#include "cns11643.h"
#include "cns11643l1.h"
#include "cns11643l2.h"
#include <libc-internal.h>
#include <assert.h>
@ -394,6 +395,16 @@ enum
#define MIN_NEEDED_OUTPUT TO_LOOP_MIN_NEEDED_TO
#define MAX_NEEDED_OUTPUT TO_LOOP_MAX_NEEDED_TO
#define LOOPFCT TO_LOOP
/* With GCC 5.3 when compiling with -Os the compiler emits a warning
that buf[0] and buf[1] may be used uninitialized. This can only
happen in the case where tmpbuf[3] is used, and in that case the
write to the tmpbuf[1] and tmpbuf[2] was assured because
ucs4_to_cns11643 would have filled in those entries. The difficulty
is in getting the compiler to see this logic because tmpbuf[0] is
involved in determining the code page and is the indicator that
tmpbuf[2] is initialized. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
#define BODY \
{ \
uint32_t ch; \
@ -645,6 +656,7 @@ enum
/* Now that we wrote the output increment the input pointer. */ \
inptr += 4; \
}
DIAG_POP_NEEDS_COMMENT;
#define EXTRA_LOOP_DECLS , int *setp
#define INIT_PARAMS int set = (*setp >> 3) & CURRENT_MASK; \
int ann = (*setp >> 3) & ~CURRENT_MASK

15
include/libc-internal.h
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@ -111,4 +111,19 @@ extern __typeof (__profile_frequency) __profile_frequency attribute_hidden;
#define DIAG_IGNORE_NEEDS_COMMENT(version, option) \
_Pragma (_DIAG_STR (GCC diagnostic ignored option))
/* Similar to DIAG_IGNORE_NEEDS_COMMENT the following macro ignores the
diagnostic OPTION but only if optimizations for size are enabled.
This is required because different warnings may be generated for
different optimization levels. For example a key piece of code may
only generate a warning when compiled at -Os, but at -O2 you could
still want the warning to be enabled to catch errors. In this case
you would use DIAG_IGNORE_Os_NEEDS_COMMENT to disable the warning
only for -Os. */
#ifdef __OPTIMIZE_SIZE__
# define DIAG_IGNORE_Os_NEEDS_COMMENT(version, option) \
_Pragma (_DIAG_STR (GCC diagnostic ignored option))
#else
# define DIAG_IGNORE_Os_NEEDS_COMMENT(version, option)
#endif
#endif /* _LIBC_INTERNAL */

8
locale/weight.h
View File

@ -61,9 +61,17 @@ findidx (const int32_t *table,
already. */
size_t cnt;
/* With GCC 5.3 when compiling with -Os the compiler warns
that seq2.back_us, which becomes usrc, might be used
uninitialized. This can't be true because we pass a length
of -1 for len at the same time which means that this loop
never executes. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
if (cp[cnt] != usrc[cnt])
break;
DIAG_POP_NEEDS_COMMENT;
if (cnt == nhere)
{

8
locale/weightwc.h
View File

@ -59,9 +59,17 @@ findidx (const int32_t *table,
already. */
size_t cnt;
/* With GCC 5.3 when compiling with -Os the compiler warns
that seq2.back_us, which becomes usrc, might be used
uninitialized. This can't be true because we pass a length
of -1 for len at the same time which means that this loop
never executes. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
for (cnt = 0; cnt < nhere && cnt < len; ++cnt)
if (cp[cnt] != usrc[cnt])
break;
DIAG_POP_NEEDS_COMMENT;
if (cnt == nhere)
{

9
nptl_db/thread_dbP.h
View File

@ -160,10 +160,19 @@ extern ps_err_e td_mod_lookup (struct ps_prochandle *ps, const char *modname,
SYM_##type##_FIELD_##field, \
(psaddr_t) 0 + (idx), (ptr), &(var))
/* With GCC 5.3 when compiling with -Os the compiler emits a warning
that slot may be used uninitialized. This is never the case since
the dynamic loader initializes the slotinfo list and
dtv_slotinfo_list will point slot at the first entry. Therefore
when DB_GET_FIELD_ADDRESS is called with a slot for ptr, the slot is
always initialized. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
#define DB_GET_FIELD_ADDRESS(var, ta, ptr, type, field, idx) \
((var) = (ptr), _td_locate_field ((ta), (ta)->ta_field_##type##_##field, \
SYM_##type##_FIELD_##field, \
(psaddr_t) 0 + (idx), &(var)))
DIAG_POP_NEEDS_COMMENT;
extern td_err_e _td_locate_field (td_thragent_t *ta,
db_desc_t desc, int descriptor_name,

11
resolv/res_send.c
View File

@ -664,7 +664,7 @@ send_vc(res_state statp,
a false-positive.
*/
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
int resplen;
DIAG_POP_NEEDS_COMMENT;
struct iovec iov[4];
@ -930,7 +930,16 @@ reopen (res_state statp, int *terrno, int ns)
* error message is received. We can thus detect
* the absence of a nameserver without timing out.
*/
/* With GCC 5.3 when compiling with -Os the compiler
emits a warning that slen may be used uninitialized,
but that is never true. Both slen and
EXT(statp).nssocks[ns] are initialized together or
the function return -1 before control flow reaches
the call to connect with slen. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
if (connect(EXT(statp).nssocks[ns], nsap, slen) < 0) {
DIAG_POP_NEEDS_COMMENT;
Aerror(statp, stderr, "connect(dg)", errno, nsap);
__res_iclose(statp, false);
return (0);

13
string/strcoll_l.c
View File

@ -24,6 +24,7 @@
#include <stdint.h>
#include <string.h>
#include <sys/param.h>
#include <libc-internal.h>
#ifndef STRING_TYPE
# define STRING_TYPE char
@ -170,7 +171,19 @@ get_next_seq (coll_seq *seq, int nrules, const unsigned char *rulesets,
}
}
/* With GCC 5.3 when compiling with -Os the compiler complains
that idx, taken from seq->idx (seq1 or seq2 from STRCOLL) may
be used uninitialized. In general this can't possibly be true
since seq1.idx and seq2.idx are initialized to zero in the
outer function. Only one case where seq->idx is restored from
seq->save_idx might result in an uninitialized idx value, but
it is guarded by a sequence of checks against backw_stop which
ensures that seq->save_idx was saved to first and contains a
valid value. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_Os_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
len = weights[idx++];
DIAG_POP_NEEDS_COMMENT;
/* Skip over indices of previous levels. */
for (int i = 0; i < pass; i++)
{