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84c426b85d
Doing all-ABIs compile testing produces a compiler warning in
stdlib/bug-getcontext.c on nios2 and tilepro (with GCC 5 branch):
bug-getcontext.c: In function 'do_test':
bug-getcontext.c:53:6: error: 'except_mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
if (mask != except_mask)
^
This warning appears nonsensical; except_mask is initialized where
it's declared. I think what must be happening here is that the
compiler is confused by the returns-twice nature of getcontext: if
there were a call to setcontext, local variables could indeed have
lost their values on the second return from getcontext. This patch
duly uses the DIAG_* macros to disable the warning here.
Tested for nios2 and tilepro (compilation only; after this patch all
the tests compile, though there are other failures) and x86_64 (full
testsuite run).
* stdlib/bug-getcontext.c: Include <libc-internal.h>.
(do_test): Disable -Wmaybe-uninitialized around uses of
except_mask.
77 lines
1.7 KiB
C
77 lines
1.7 KiB
C
/* BZ 12420 */
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#include <errno.h>
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#include <fenv.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <ucontext.h>
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#include <libc-internal.h>
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static int
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do_test (void)
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{
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if (FE_ALL_EXCEPT == 0)
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{
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printf("Skipping test; no support for FP exceptions.\n");
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return 0;
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}
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int except_mask = 0;
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#ifdef FE_DIVBYZERO
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except_mask |= FE_DIVBYZERO;
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#endif
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#ifdef FE_INVALID
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except_mask |= FE_INVALID;
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#endif
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#ifdef FE_OVERFLOW
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except_mask |= FE_OVERFLOW;
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#endif
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#ifdef FE_UNDERFLOW
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except_mask |= FE_UNDERFLOW;
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#endif
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int status = feenableexcept (except_mask);
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except_mask = fegetexcept ();
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if (except_mask == -1)
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{
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printf("\nBefore getcontext(): fegetexcept returned: %d\n",
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except_mask);
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return 1;
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}
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ucontext_t ctx;
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status = getcontext(&ctx);
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if (status)
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{
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printf("\ngetcontext failed, errno: %d.\n", errno);
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return 1;
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}
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printf ("\nDone with getcontext()!\n");
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fflush (NULL);
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/* On nios2 and tilepro, GCC 5 warns that except_mask may be used
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uninitialized. Because it is always initialized and nothing in
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this test ever calls setcontext (a setcontext call could result
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in local variables being clobbered on the second return from
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getcontext), in fact an uninitialized use is not possible. */
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DIAG_PUSH_NEEDS_COMMENT;
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DIAG_IGNORE_NEEDS_COMMENT (5, "-Wmaybe-uninitialized");
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int mask = fegetexcept ();
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if (mask != except_mask)
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{
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printf("\nAfter getcontext(): fegetexcept returned: %d, expected: %d.\n",
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mask, except_mask);
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return 1;
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}
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printf("\nAt end fegetexcept() returned %d, expected: %d.\n",
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mask, except_mask);
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DIAG_POP_NEEDS_COMMENT;
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return 0;
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}
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#define TEST_FUNCTION do_test ()
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#include "../test-skeleton.c"
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