From ccab11b0e8f2a2daff99f3376554ba1852507518 Mon Sep 17 00:00:00 2001
From: Alex Shlyapnikov <alekseys@google.com>
Date: Tue, 20 Jun 2017 21:23:02 +0000
Subject: [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

llvm-svn: 305858
---
 .../sanitizer_allocator_combined.h                 | 49 ++++++----------------
 1 file changed, 12 insertions(+), 37 deletions(-)

(limited to 'compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h')

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h
index 90ccb177168..efd25cadfe7 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_combined.h
@@ -24,22 +24,18 @@ template <class PrimaryAllocator, class AllocatorCache,
           class SecondaryAllocator>  // NOLINT
 class CombinedAllocator {
  public:
-  void InitCommon(bool may_return_null, s32 release_to_os_interval_ms) {
-    primary_.Init(release_to_os_interval_ms);
-    atomic_store(&may_return_null_, may_return_null, memory_order_relaxed);
-  }
+  typedef typename SecondaryAllocator::FailureHandler FailureHandler;
 
-  void InitLinkerInitialized(
-      bool may_return_null, s32 release_to_os_interval_ms) {
-    secondary_.InitLinkerInitialized(may_return_null);
+  void InitLinkerInitialized(s32 release_to_os_interval_ms) {
+    primary_.Init(release_to_os_interval_ms);
+    secondary_.InitLinkerInitialized();
     stats_.InitLinkerInitialized();
-    InitCommon(may_return_null, release_to_os_interval_ms);
   }
 
-  void Init(bool may_return_null, s32 release_to_os_interval_ms) {
-    secondary_.Init(may_return_null);
+  void Init(s32 release_to_os_interval_ms) {
+    primary_.Init(release_to_os_interval_ms);
+    secondary_.Init();
     stats_.Init();
-    InitCommon(may_return_null, release_to_os_interval_ms);
   }
 
   void *Allocate(AllocatorCache *cache, uptr size, uptr alignment) {
@@ -47,7 +43,7 @@ class CombinedAllocator {
     if (size == 0)
       size = 1;
     if (size + alignment < size)
-      return ReturnNullOrDieOnBadRequest();
+      return FailureHandler::OnBadRequest();
     uptr original_size = size;
     // If alignment requirements are to be fulfilled by the frontend allocator
     // rather than by the primary or secondary, passing an alignment lower than
@@ -55,44 +51,24 @@ class CombinedAllocator {
     // alignment check.
     if (alignment > 8)
       size = RoundUpTo(size, alignment);
-    void *res;
-    bool from_primary = primary_.CanAllocate(size, alignment);
     // The primary allocator should return a 2^x aligned allocation when
     // requested 2^x bytes, hence using the rounded up 'size' when being
     // serviced by the primary (this is no longer true when the primary is
     // using a non-fixed base address). The secondary takes care of the
     // alignment without such requirement, and allocating 'size' would use
     // extraneous memory, so we employ 'original_size'.
-    if (from_primary)
+    void *res;
+    if (primary_.CanAllocate(size, alignment))
       res = cache->Allocate(&primary_, primary_.ClassID(size));
     else
       res = secondary_.Allocate(&stats_, original_size, alignment);
+    if (!res)
+      return FailureHandler::OnOOM();
     if (alignment > 8)
       CHECK_EQ(reinterpret_cast<uptr>(res) & (alignment - 1), 0);
     return res;
   }
 
-  bool MayReturnNull() const {
-    return atomic_load(&may_return_null_, memory_order_acquire);
-  }
-
-  void *ReturnNullOrDieOnBadRequest() {
-    if (MayReturnNull())
-      return nullptr;
-    ReportAllocatorCannotReturnNull(false);
-  }
-
-  void *ReturnNullOrDieOnOOM() {
-    if (MayReturnNull())
-      return nullptr;
-    ReportAllocatorCannotReturnNull(true);
-  }
-
-  void SetMayReturnNull(bool may_return_null) {
-    secondary_.SetMayReturnNull(may_return_null);
-    atomic_store(&may_return_null_, may_return_null, memory_order_release);
-  }
-
   s32 ReleaseToOSIntervalMs() const {
     return primary_.ReleaseToOSIntervalMs();
   }
@@ -213,6 +189,5 @@ class CombinedAllocator {
   PrimaryAllocator primary_;
   SecondaryAllocator secondary_;
   AllocatorGlobalStats stats_;
-  atomic_uint8_t may_return_null_;
 };
 
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