[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

1 files changed, 4 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_linux.cc b/lib/sanitizer_common/sanitizer_linux.cc
index 6274b248e..89c76422c 100644
--- a/lib/sanitizer_common/sanitizer_linux.cc
+++ b/lib/sanitizer_common/sanitizer_linux.cc
@@ -459,6 +459,10 @@ u64 NanoTime() {
   return (u64)tv.tv_sec * 1000*1000*1000 + tv.tv_usec * 1000;
 }
 
+uptr internal_clock_gettime(__sanitizer_clockid_t clk_id, void *tp) {
+  return internal_syscall_ptr(SYSCALL(clock_gettime), clk_id, tp);
+}
+
 // Like getenv, but reads env directly from /proc (on Linux) or parses the
 // 'environ' array (on FreeBSD) and does not use libc. This function should be
 // called first inside __asan_init.