[msan] Implement __sanitizer_get_current_allocated_bytes

__sanitizer_get_current_allocated_bytes had as body, but allocator
caches were not registered to collect stats. It's done by
SizeClassAllocator64LocalCache::Init().

Reviewed By: kstoimenov

Differential Revision: https://reviews.llvm.org/D151352

compiler-rt/lib/msan/msan_allocator.cpp

@@ -145,8 +145,13 @@ AllocatorCache *GetAllocatorCache(MsanThreadLocalMallocStorage *ms) {
   return reinterpret_cast<AllocatorCache *>(ms->allocator_cache);
 }
 
+void MsanThreadLocalMallocStorage::Init() {
+  allocator.InitCache(GetAllocatorCache(this));
+}
+
 void MsanThreadLocalMallocStorage::CommitBack() {
   allocator.SwallowCache(GetAllocatorCache(this));
+  allocator.DestroyCache(GetAllocatorCache(this));
 }
 
 static void *MsanAllocate(StackTrace *stack, uptr size, uptr alignment,
@@ -393,3 +398,5 @@ const void *__sanitizer_get_allocated_begin(const void *p) {
 }
 
 uptr __sanitizer_get_allocated_size(const void *p) { return AllocationSize(p); }
+
+void __sanitizer_purge_allocator() { allocator.ForceReleaseToOS(); }

compiler-rt/lib/msan/msan_allocator.h

@@ -20,6 +20,7 @@ namespace __msan {
 struct MsanThreadLocalMallocStorage {
   // Allocator cache contains atomic_uint64_t which must be 8-byte aligned.
   ALIGNED(8) uptr allocator_cache[96 * (512 * 8 + 16)];  // Opaque.
+  void Init();
   void CommitBack();
 
  private:

compiler-rt/lib/msan/msan_thread.cpp

@@ -47,6 +47,7 @@ void MsanThread::Init() {
   CHECK(MEM_IS_APP(stack_.bottom));
   CHECK(MEM_IS_APP(stack_.top - 1));
   ClearShadowForThreadStackAndTLS();
+  malloc_storage().Init();
 }
 
 void MsanThread::TSDDtor(void *tsd) {

compiler-rt/test/sanitizer_common/TestCases/allocator_interface.cpp

@@ -5,7 +5,7 @@
 // UNSUPPORTED: ubsan
 
 // FIXME: implementation is incomplete.
-// XFAIL: msan, lsan, hwasan
+// XFAIL: lsan, hwasan
 
 #include <assert.h>
 #include <sanitizer/allocator_interface.h>