[Sanitizer] Introduce Allocator::may_return_null bool flag.

Summary:
Turn "allocator_may_return_null" common flag into an
Allocator::may_return_null bool flag. We want to make sure
that common flags are immutable after initialization. There
are cases when we want to change this flag in the allocator
at runtime: e.g. in unit tests and during ASan activation
on Android.

Test Plan: regression test suite, real-life applications

Reviewers: kcc, eugenis

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D6623

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@224148 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 4 deletions

diff --git a/lib/msan/msan_interceptors.cc b/lib/msan/msan_interceptors.cc
index bbdf18e16..608fb95bd 100644
--- a/lib/msan/msan_interceptors.cc
+++ b/lib/msan/msan_interceptors.cc
@@ -925,10 +925,8 @@ INTERCEPTOR(SSIZE_T, recvfrom, int fd, void *buf, SIZE_T len, int flags,
 }
 
 INTERCEPTOR(void *, calloc, SIZE_T nmemb, SIZE_T size) {
-  if (CallocShouldReturnNullDueToOverflow(size, nmemb))
-    return AllocatorReturnNull();
   GET_MALLOC_STACK_TRACE;
-  if (!msan_inited) {
+  if (UNLIKELY(!msan_inited)) {
     // Hack: dlsym calls calloc before REAL(calloc) is retrieved from dlsym.
     const SIZE_T kCallocPoolSize = 1024;
     static uptr calloc_memory_for_dlsym[kCallocPoolSize];
@@ -939,7 +937,7 @@ INTERCEPTOR(void *, calloc, SIZE_T nmemb, SIZE_T size) {
     CHECK(allocated < kCallocPoolSize);
     return mem;
   }
-  return MsanReallocate(&stack, 0, nmemb * size, sizeof(u64), true);
+  return MsanCalloc(&stack, nmemb, size);
 }
 
 INTERCEPTOR(void *, realloc, void *ptr, SIZE_T size) {