[Sanitizers] Secondary allocator respects allocator_may_return_null=1.

Summary:
Context: https://github.com/google/sanitizers/issues/740.

Making secondary allocator to respect allocator_may_return_null=1 flag
and return nullptr when "out of memory" happens.

More changes in primary allocator and operator new will follow.

Reviewers: eugenis

Subscribers: kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D34243

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@305569 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/sanitizer_common/sanitizer_posix.cc b/lib/sanitizer_common/sanitizer_posix.cc
index 9916f4d38..4184a84c7 100644
--- a/lib/sanitizer_common/sanitizer_posix.cc
+++ b/lib/sanitizer_common/sanitizer_posix.cc
@@ -22,6 +22,7 @@
 #include "sanitizer_procmaps.h"
 #include "sanitizer_stacktrace.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <sys/mman.h>
@@ -145,6 +146,21 @@ void UnmapOrDie(void *addr, uptr size) {
   DecreaseTotalMmap(size);
 }
 
+void *MmapOrDieOnFatalError(uptr size, const char *mem_type) {
+  size = RoundUpTo(size, GetPageSizeCached());
+  uptr res = internal_mmap(nullptr, size,
+                           PROT_READ | PROT_WRITE,
+                           MAP_PRIVATE | MAP_ANON, -1, 0);
+  int reserrno;
+  if (internal_iserror(res, &reserrno)) {
+    if (reserrno == ENOMEM)
+      return nullptr;
+    ReportMmapFailureAndDie(size, mem_type, "allocate", reserrno);
+  }
+  IncreaseTotalMmap(size);
+  return (void *)res;
+}
+
 // We want to map a chunk of address space aligned to 'alignment'.
 // We do it by maping a bit more and then unmaping redundant pieces.
 // We probably can do it with fewer syscalls in some OS-dependent way.