From 9be36fb8cb5bcdab5bbbc7a36388dc9a3d1cc397 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 26 Mar 2014 18:59:08 +0000 Subject: [PATCH] Make x86_64 fegetenv preserve exception mask (bug 16198). Bug 16198 is x86_64 fegetenv wrongly masking exceptions for which traps are enabled, because that's a side-effect of the fnstenv instruction. This patch fixes it to use fldenv immediately after fnstenv, like the i386 version. Tested x86_64 and x86. [BZ #16198] * sysdeps/x86_64/fpu/fegetenv.c (fegetenv): Use fldenv after fnstenv. * math/test-fenv-preserve.c: New file. * math/Makefile (tests): Add test-fenv-preserve. --- ChangeLog | 8 +++++++ NEWS | 8 +++---- math/Makefile | 2 +- math/test-fenv-preserve.c | 53 +++++++++++++++++++++++++++++++++++++++++++ sysdeps/x86_64/fpu/fegetenv.c | 3 +++ 5 files changed, 69 insertions(+), 5 deletions(-) create mode 100644 math/test-fenv-preserve.c diff --git a/ChangeLog b/ChangeLog index c3d2ada..20af1be 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2014-03-26 Joseph Myers + + [BZ #16198] + * sysdeps/x86_64/fpu/fegetenv.c (fegetenv): Use fldenv after + fnstenv. + * math/test-fenv-preserve.c: New file. + * math/Makefile (tests): Add test-fenv-preserve. + 2014-03-26 Will Newton * benchtests/bench-strtod.c (TIMEOUT): Define to 10. diff --git a/NEWS b/NEWS index 1dbce87..6f16584 100644 --- a/NEWS +++ b/NEWS @@ -9,10 +9,10 @@ Version 2.20 * The following bugs are resolved with this release: - 15347, 15804, 15894, 16002, 16284, 16357, 16447, 16532, 16545, 16574, - 16599, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16634, 16639, - 16642, 16649, 16670, 16674, 16677, 16680, 16683, 16689, 16695, 16701, - 16706, 16707, 16712, 16713, 16714, 16731, 16743. + 15347, 15804, 15894, 16002, 16198, 16284, 16357, 16447, 16532, 16545, + 16574, 16599, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16634, + 16639, 16642, 16649, 16670, 16674, 16677, 16680, 16683, 16689, 16695, + 16701, 16706, 16707, 16712, 16713, 16714, 16731, 16743. * Running the testsuite no longer terminates as soon as a test fails. Instead, a file tests.sum (xtests.sum from "make xcheck") is generated, diff --git a/math/Makefile b/math/Makefile index 09d14a0..c13ca80 100644 --- a/math/Makefile +++ b/math/Makefile @@ -90,7 +90,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \ test-misc test-fpucw test-fpucw-ieee tst-definitions test-tgmath \ test-tgmath-ret bug-nextafter bug-nexttoward bug-tgmath1 \ test-tgmath-int test-tgmath2 test-powl tst-CMPLX tst-CMPLX2 test-snan \ - test-fenv-tls $(tests-static) + test-fenv-tls test-fenv-preserve $(tests-static) tests-static = test-fpucw-static test-fpucw-ieee-static # We do the `long double' tests only if this data type is available and # distinct from `double'. diff --git a/math/test-fenv-preserve.c b/math/test-fenv-preserve.c new file mode 100644 index 0000000..8288b2c --- /dev/null +++ b/math/test-fenv-preserve.c @@ -0,0 +1,53 @@ +/* Test fegetenv preserves exception mask (bug 16198). + Copyright (C) 2014 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include + +static int +do_test (void) +{ + fenv_t env; + + if (feenableexcept (FE_INVALID) != 0) + { + puts ("feenableexcept (FE_INVALID) failed, cannot test"); + return 0; + } + + if (fegetenv (&env) != 0) + { + puts ("fegetenv failed, cannot test"); + return 0; + } + + int ret = fegetexcept (); + if (ret == FE_INVALID) + { + puts ("fegetenv preserved exception mask, OK"); + return 0; + } + else + { + printf ("fegetexcept returned %d, expected %d\n", ret, FE_INVALID); + return 1; + } +} + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" diff --git a/sysdeps/x86_64/fpu/fegetenv.c b/sysdeps/x86_64/fpu/fegetenv.c index 364f917..0e0c269 100644 --- a/sysdeps/x86_64/fpu/fegetenv.c +++ b/sysdeps/x86_64/fpu/fegetenv.c @@ -22,6 +22,9 @@ int fegetenv (fenv_t *envp) { __asm__ ("fnstenv %0\n" + /* fnstenv changes the exception mask, so load back the + stored environment. */ + "fldenv %0\n" "stmxcsr %1" : "=m" (*envp), "=m" (envp->__mxcsr)); /* Success. */ -- 2.7.4