diff options
author | Kostya Kortchinsky <kostyak@google.com> | 2017-12-13 16:23:54 +0000 |
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committer | Kostya Kortchinsky <kostyak@google.com> | 2017-12-13 16:23:54 +0000 |
commit | ad977cc9521dd2e264a2cdcbba3b2afc5084d0d3 (patch) | |
tree | 58bcbf560f646e8ee54971713dbd3ffa0cad8312 /lib/sanitizer_common/sanitizer_linux_libcdep.cc | |
parent | 51bfa63ac5b93a2dedd68044f32ded4cfb0594f9 (diff) |
[sanitizer] Introduce a vDSO aware timing function
Summary:
See D40657 & D40679 for previous versions of this patch & description.
A couple of things were fixed here to have it not break some bots.
Weak symbols can't be used with `SANITIZER_GO` so the previous version was
breakin TsanGo. I set up some additional local tests and those pass now.
I changed the workaround for the glibc vDSO issue: `__progname` is initialized
after the vDSO and is actually public and of known type, unlike
`__vdso_clock_gettime`. This works better, and with all compilers.
The rest is the same.
Reviewers: alekseyshl
Reviewed By: alekseyshl
Subscribers: srhines, kubamracek, krytarowski, llvm-commits, #sanitizers
Differential Revision: https://reviews.llvm.org/D41121
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@320594 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/sanitizer_common/sanitizer_linux_libcdep.cc')
-rw-r--r-- | lib/sanitizer_common/sanitizer_linux_libcdep.cc | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/lib/sanitizer_common/sanitizer_linux_libcdep.cc b/lib/sanitizer_common/sanitizer_linux_libcdep.cc index c68f2146d..80d38215d 100644 --- a/lib/sanitizer_common/sanitizer_linux_libcdep.cc +++ b/lib/sanitizer_common/sanitizer_linux_libcdep.cc @@ -707,6 +707,47 @@ void LogMessageOnPrintf(const char *str) { #endif // SANITIZER_LINUX +#if SANITIZER_LINUX && !SANITIZER_GO +// glibc crashes when using clock_gettime from a preinit_array function as the +// vDSO function pointers haven't been initialized yet. __progname is +// initialized after the vDSO function pointers, so if it exists, is not null +// and is not empty, we can use clock_gettime. +extern "C" SANITIZER_WEAK_ATTRIBUTE char *__progname; +INLINE bool CanUseVDSO() { + // Bionic is safe, it checks for the vDSO function pointers to be initialized. + if (SANITIZER_ANDROID) + return true; + if (&__progname && __progname && *__progname) + return true; + return false; +} + +// MonotonicNanoTime is a timing function that can leverage the vDSO by calling +// clock_gettime. real_clock_gettime only exists if clock_gettime is +// intercepted, so define it weakly and use it if available. +extern "C" SANITIZER_WEAK_ATTRIBUTE +int real_clock_gettime(u32 clk_id, void *tp); +u64 MonotonicNanoTime() { + timespec ts; + if (CanUseVDSO()) { + if (&real_clock_gettime) + real_clock_gettime(CLOCK_MONOTONIC, &ts); + else + clock_gettime(CLOCK_MONOTONIC, &ts); + } else { + internal_clock_gettime(CLOCK_MONOTONIC, &ts); + } + return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec; +} +#else +// Non-Linux & Go always use the syscall. +u64 MonotonicNanoTime() { + timespec ts; + internal_clock_gettime(CLOCK_MONOTONIC, &ts); + return (u64)ts.tv_sec * (1000ULL * 1000 * 1000) + ts.tv_nsec; +} +#endif // SANITIZER_LINUX && !SANITIZER_GO + } // namespace __sanitizer -#endif // SANITIZER_FREEBSD || SANITIZER_LINUX +#endif // SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_NETBSD |