[Sanitizers] Move cached allocator_may_return_null flag to sanitizer_allocator

Summary:
Move cached allocator_may_return_null flag to sanitizer_allocator.cc and
provide API to consolidate and unify the behavior of all specific allocators.

Make all sanitizers using CombinedAllocator to follow
AllocatorReturnNullOrDieOnOOM() rules to behave the same way when OOM
happens.

When OOM happens, turn allocator_out_of_memory flag on regardless of
allocator_may_return_null flag value (it used to not to be set when
allocator_may_return_null == true).

release_to_os_interval_ms and rss_limit_exceeded will likely be moved to
sanitizer_allocator.cc too (later).

Reviewers: eugenis

Subscribers: srhines, kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D34310

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@305858 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 21 insertions, 5 deletions

diff --git a/lib/sanitizer_common/sanitizer_allocator.h b/lib/sanitizer_common/sanitizer_allocator.h
index 9a37a2f21..f59c13d1c 100644
--- a/lib/sanitizer_common/sanitizer_allocator.h
+++ b/lib/sanitizer_common/sanitizer_allocator.h
@@ -24,12 +24,28 @@
 
 namespace __sanitizer {
 
-// Returns true if ReportAllocatorCannotReturnNull(true) was called.
-// Can be use to avoid memory hungry operations.
-bool IsReportingOOM();
+// Since flags are immutable and allocator behavior can be changed at runtime
+// (unit tests or ASan on Android are some examples), allocator_may_return_null
+// flag value is cached here and can be altered later.
+bool AllocatorMayReturnNull();
+void SetAllocatorMayReturnNull(bool may_return_null);
 
-// Prints error message and kills the program.
-void NORETURN ReportAllocatorCannotReturnNull(bool out_of_memory);
+// Allocator failure handling policies:
+// Implements AllocatorMayReturnNull policy, returns null when the flag is set,
+// dies otherwise.
+struct ReturnNullOrDieOnFailure {
+  static void *OnBadRequest();
+  static void *OnOOM();
+};
+// Always dies on the failure.
+struct DieOnFailure {
+  static void *OnBadRequest();
+  static void *OnOOM();
+};
+
+// Returns true if allocator detected OOM condition. Can be used to avoid memory
+// hungry operations. Set when AllocatorReturnNullOrDieOnOOM() is called.
+bool IsAllocatorOutOfMemory();
 
 // Allocators call these callbacks on mmap/munmap.
 struct NoOpMapUnmapCallback {