From 84c426b85db7cc595f8c5d3ec549009490ca6299 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Fri, 11 Nov 2016 21:05:51 +0000 Subject: Ignore -Wmaybe-uninitialized in stdlib/bug-getcontext.c. 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 . (do_test): Disable -Wmaybe-uninitialized around uses of except_mask. --- ChangeLog | 4 ++++ stdlib/bug-getcontext.c | 9 +++++++++ 2 files changed, 13 insertions(+) diff --git a/ChangeLog b/ChangeLog index 7c72585..95f983f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,9 @@ 2016-11-11 Joseph Myers + * stdlib/bug-getcontext.c: Include . + (do_test): Disable -Wmaybe-uninitialized around uses of + except_mask. + * sysdeps/unix/sysv/linux/sh/sys/user.h: Include . 2016-11-10 Chris Metcalf diff --git a/stdlib/bug-getcontext.c b/stdlib/bug-getcontext.c index 133ee91..c407212 100644 --- a/stdlib/bug-getcontext.c +++ b/stdlib/bug-getcontext.c @@ -5,6 +5,7 @@ #include #include #include +#include static int do_test (void) @@ -49,6 +50,13 @@ do_test (void) printf ("\nDone with getcontext()!\n"); fflush (NULL); + /* On nios2 and tilepro, GCC 5 warns that except_mask may be used + uninitialized. Because it is always initialized and nothing in + this test ever calls setcontext (a setcontext call could result + in local variables being clobbered on the second return from + getcontext), in fact an uninitialized use is not possible. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (5, "-Wmaybe-uninitialized"); int mask = fegetexcept (); if (mask != except_mask) { @@ -59,6 +67,7 @@ do_test (void) printf("\nAt end fegetexcept() returned %d, expected: %d.\n", mask, except_mask); + DIAG_POP_NEEDS_COMMENT; return 0; } -- cgit v1.1