commit a00b9229c3750df9c6c3edb4a057b407250880b4
author Kostya Kortchinsky <kostyak@google.com> Fri Jan 20 18:32:18 2017 +0000
committer Kostya Kortchinsky <kostyak@google.com> Fri Jan 20 18:32:18 2017 +0000
tree 37ea46ea214072c270e8f928bd7a97659d4e277b
parent 856548a616a56fc716a87035198151b3c14fee36

[scudo] Replacing std::atomic with Sanitizer's atomics

Summary:
In an effort to getting rid of dependencies to external libraries, we are
replacing atomic PackedHeader use of std::atomic with Sanitizer's
atomic_uint64_t, which allows us to avoid -latomic.

Reviewers: kcc, phosek, alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D28864

llvm-svn: 292630

compiler-rt/lib/scudo/scudo_allocator.cpp

diff --git a/compiler-rt/lib/scudo/scudo_allocator.cpp b/compiler-rt/lib/scudo/scudo_allocator.cpp
index 62fdf77..a6d6aaf 100644
--- a/compiler-rt/lib/scudo/scudo_allocator.cpp
+++ b/compiler-rt/lib/scudo/scudo_allocator.cpp
@@ -125,8 +125,7 @@
     UnpackedHeader NewUnpackedHeader;
     const AtomicPackedHeader *AtomicHeader =
         reinterpret_cast<const AtomicPackedHeader *>(this);
-    PackedHeader NewPackedHeader =
-        AtomicHeader->load(std::memory_order_relaxed);
+    PackedHeader NewPackedHeader = atomic_load_relaxed(AtomicHeader);
     NewUnpackedHeader = bit_cast<UnpackedHeader>(NewPackedHeader);
     return (NewUnpackedHeader.Checksum == computeChecksum(&NewUnpackedHeader));
   }
@@ -135,8 +134,7 @@
   void loadHeader(UnpackedHeader *NewUnpackedHeader) const {
     const AtomicPackedHeader *AtomicHeader =
         reinterpret_cast<const AtomicPackedHeader *>(this);
-    PackedHeader NewPackedHeader =
-        AtomicHeader->load(std::memory_order_relaxed);
+    PackedHeader NewPackedHeader = atomic_load_relaxed(AtomicHeader);
     *NewUnpackedHeader = bit_cast<UnpackedHeader>(NewPackedHeader);
     if (NewUnpackedHeader->Checksum != computeChecksum(NewUnpackedHeader)) {
       dieWithMessage("ERROR: corrupted chunk header at address %p\n", this);
@@ -149,7 +147,7 @@
     PackedHeader NewPackedHeader = bit_cast<PackedHeader>(*NewUnpackedHeader);
     AtomicPackedHeader *AtomicHeader =
         reinterpret_cast<AtomicPackedHeader *>(this);
-    AtomicHeader->store(NewPackedHeader, std::memory_order_relaxed);
+    atomic_store_relaxed(AtomicHeader, NewPackedHeader);
   }
 
   // Packs and stores the header, computing the checksum in the process. We
@@ -162,10 +160,10 @@
     PackedHeader OldPackedHeader = bit_cast<PackedHeader>(*OldUnpackedHeader);
     AtomicPackedHeader *AtomicHeader =
         reinterpret_cast<AtomicPackedHeader *>(this);
-    if (!AtomicHeader->compare_exchange_strong(OldPackedHeader,
-                                               NewPackedHeader,
-                                               std::memory_order_relaxed,
-                                               std::memory_order_relaxed)) {
+    if (!atomic_compare_exchange_strong(AtomicHeader,
+                                        &OldPackedHeader,
+                                        NewPackedHeader,
+                                        memory_order_relaxed)) {
       dieWithMessage("ERROR: race on chunk header at address %p\n", this);
     }
   }