[asan] allocate AsanThreadContext using LowLevelAllocator instead of mmap to save space

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@192980 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/asan/asan_thread.cc b/lib/asan/asan_thread.cc
index a52ab5a0a..00d62c0e7 100644
--- a/lib/asan/asan_thread.cc
+++ b/lib/asan/asan_thread.cc
@@ -43,8 +43,12 @@ void AsanThreadContext::OnFinished() {
 static ALIGNED(16) char thread_registry_placeholder[sizeof(ThreadRegistry)];
 static ThreadRegistry *asan_thread_registry;
 
+static BlockingMutex mu_for_thread_context(LINKER_INITIALIZED);
+static LowLevelAllocator allocator_for_thread_context;
+
 static ThreadContextBase *GetAsanThreadContext(u32 tid) {
-  void *mem = MmapOrDie(sizeof(AsanThreadContext), "AsanThreadContext");
+  BlockingMutexLock lock(&mu_for_thread_context);
+  void *mem = allocator_for_thread_context.Allocate(sizeof(AsanThreadContext));
   return new(mem) AsanThreadContext(tid);
 }