[compiler-rt] r324011 - [sanitizer] Implement NanoTime & MonotonicNanoTime for Windows

[Kostya Kortchinsky via llvm-commits]

Author: cryptoad
Date: Thu Feb  1 13:38:14 2018
New Revision: 324011

URL: http://llvm.org/viewvc/llvm-project?rev=324011&view=rev
Log:
[sanitizer] Implement NanoTime & MonotonicNanoTime for Windows

Summary:
Implement `MonotonicNanoTime` using `QueryPerformanceCounter`.

This function is used by Scudo & the 64-bit Primary allocator. Implementing it
now means that the release-to-OS mechanism of the Primary will kick in (it
never did since the function returned 0 always), but `ReleaseMemoryPagesToOS` is
still not currently implemented for Windows.

Performance wise, this adds a syscall & a 64-bit division per call to
`MonotonicNanoTime` so the impact might not be negligible, but I don't think
there is a way around it.

Reviewers: rnk, alekseyshl, amccarth

Reviewed By: alekseyshl, amccarth

Subscribers: amccarth, flowerhack, kubamracek, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D42579

Modified:
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc
    compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc?rev=324011&r1=324010&r2=324011&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_flags.inc Thu Feb  1 13:38:14 2018
@@ -132,7 +132,8 @@ COMMON_FLAG(uptr, soft_rss_limit_mb, 0,
             " This limit does not affect memory allocations other than"
             " malloc/new.")
 COMMON_FLAG(bool, heap_profile, false, "Experimental heap profiler, asan-only")
-COMMON_FLAG(s32, allocator_release_to_os_interval_ms, 5000,
+COMMON_FLAG(s32, allocator_release_to_os_interval_ms,
+            (SANITIZER_FUCHSIA || SANITIZER_WINDOWS) ? -1 : 5000,
             "Only affects a 64-bit allocator. If set, tries to release unused "
             "memory to the OS, but not more often than this interval (in "
             "milliseconds). Negative values mean do not attempt to release "

Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc?rev=324011&r1=324010&r2=324011&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_win.cc Thu Feb  1 13:38:14 2018
@@ -502,12 +502,19 @@ void SleepForMillis(int millis) {
 }
 
 u64 NanoTime() {
-  return 0;
+  static LARGE_INTEGER frequency = {0};
+  LARGE_INTEGER counter;
+  if (UNLIKELY(frequency.QuadPart == 0)) {
+    QueryPerformanceFrequency(&frequency);
+    CHECK_NE(frequency.QuadPart, 0);
+  }
+  QueryPerformanceCounter(&counter);
+  counter.QuadPart *= 1000ULL * 1000000ULL;
+  counter.QuadPart /= frequency.QuadPart;
+  return counter.QuadPart;
 }
 
-u64 MonotonicNanoTime() {
-  return 0;
-}
+u64 MonotonicNanoTime() { return NanoTime(); }
 
 void Abort() {
   internal__exit(3);