Merge commit 'e0aeebe6803a' from apple/main into swift/next

Author: git apple-llvm automerger

compiler-rt/lib/dfsan/dfsan.cpp

@@ -475,8 +475,10 @@ static void dfsan_init(int argc, char **argv, char **envp) {
 
   ::InitializePlatformEarly();
 
-  if (!MmapFixedNoReserve(ShadowAddr(), UnusedAddr() - ShadowAddr()))
+  if (!MmapFixedSuperNoReserve(ShadowAddr(), UnusedAddr() - ShadowAddr()))
     Die();
+  if (common_flags()->use_madv_dontdump)
+    DontDumpShadowMemory(ShadowAddr(), UnusedAddr() - ShadowAddr());
 
   // Protect the region of memory we don't use, to preserve the one-to-one
   // mapping from application to shadow memory. But if ASLR is disabled, Linux

compiler-rt/test/dfsan/release_shadow_space.c

@@ -1,4 +1,5 @@
-// RUN: %clang_dfsan %s -o %t && %run %t
+// DFSAN_OPTIONS=no_huge_pages_for_shadow=false RUN: %clang_dfsan %s -o %t && %run %t
+// DFSAN_OPTIONS=no_huge_pages_for_shadow=true RUN: %clang_dfsan %s -o %t && %run %t
 
 #include <assert.h>
 #include <sanitizer/dfsan_interface.h>