[ASan] Change activation strategy.

Now ASan deactivation doesn't modify common or ASan-specific runtime
flags. Flags stay constant after initialization, and "deactivation"
instead stashes initialized runtime state, and deactivates the
runtime. Activation then just restores the original state (possibly,
overriden by some activation flags provided in system property on
Android).

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@224614 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/sanitizer_common/sanitizer_allocator.h b/lib/sanitizer_common/sanitizer_allocator.h
index d3723eb1d..d749acb90 100644
--- a/lib/sanitizer_common/sanitizer_allocator.h
+++ b/lib/sanitizer_common/sanitizer_allocator.h
@@ -1300,8 +1300,12 @@ class CombinedAllocator {
     return res;
   }
 
+  bool MayReturnNull() const {
+    return atomic_load(&may_return_null_, memory_order_acquire);
+  }
+
   void *ReturnNullOrDie() {
-    if (atomic_load(&may_return_null_, memory_order_acquire))
+    if (MayReturnNull())
       return 0;
     ReportAllocatorCannotReturnNull();
   }