[sanitizer] Reduce stack depot size on Android.

Summary:
The default setting kTabSizeLog=20 results in an 8Mb global hash table,
almost all of it in private pages. That is not a sane setting in a
mobile, system-wide use case: with ~150 concurrent processes stack
depot will account for more than 1Gb of RAM.

Reviewers: kcc, pcc

Subscribers: srhines, kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D56333

llvm-svn: 350443

2 files changed, 2 insertions, 2 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.cc b/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.cc
index 3bd5b677a1f..6aab9848522 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.cc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.cc
@@ -26,7 +26,7 @@ struct StackDepotNode {
   u32 tag;
   uptr stack[1];  // [size]
 
-  static const u32 kTabSizeLog = 20;
+  static const u32 kTabSizeLog = SANITIZER_ANDROID ? 16 : 20;
   // Lower kTabSizeLog bits are equal for all items in one bucket.
   // We use these bits to store the per-stack use counter.
   static const u32 kUseCountBits = kTabSizeLog;
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.h b/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.h
index cb7345002a4..e22ed2e38e5 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_stackdepot.h
@@ -32,7 +32,7 @@ struct StackDepotHandle {
   void inc_use_count_unsafe();
 };
 
-const int kStackDepotMaxUseCount = 1U << 20;
+const int kStackDepotMaxUseCount = 1U << (SANITIZER_ANDROID ? 16 : 20);
 
 StackDepotStats *StackDepotGetStats();
 u32 StackDepotPut(StackTrace stack);