[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

6 files changed, 11 insertions, 17 deletions

diff --git a/compiler-rt/lib/scudo/scudo_allocator.cpp b/compiler-rt/lib/scudo/scudo_allocator.cpp
index 62fdf77f5d0..a6d6aafe31f 100644
--- a/compiler-rt/lib/scudo/scudo_allocator.cpp
+++ b/compiler-rt/lib/scudo/scudo_allocator.cpp
@@ -125,8 +125,7 @@ struct ScudoChunk : UnpackedHeader {
     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 @@ struct ScudoChunk : UnpackedHeader {
   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 @@ struct ScudoChunk : UnpackedHeader {
     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 @@ struct ScudoChunk : UnpackedHeader {
     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);
     }
   }
diff --git a/compiler-rt/lib/scudo/scudo_allocator.h b/compiler-rt/lib/scudo/scudo_allocator.h
index b9fc82dc672..5f5225b3628 100644
--- a/compiler-rt/lib/scudo/scudo_allocator.h
+++ b/compiler-rt/lib/scudo/scudo_allocator.h
@@ -22,8 +22,6 @@
 # error "The Scudo hardened allocator is currently only supported on Linux."
 #endif
 
-#include <atomic>
-
 namespace __scudo {
 
 enum AllocType : u8 {
@@ -58,7 +56,7 @@ struct UnpackedHeader {
   u64 Salt        : 8;
 };
 
-typedef std::atomic<PackedHeader> AtomicPackedHeader;
+typedef atomic_uint64_t AtomicPackedHeader;
 COMPILER_CHECK(sizeof(UnpackedHeader) == sizeof(PackedHeader));
 
 // Minimum alignment of 8 bytes for 32-bit, 16 for 64-bit
diff --git a/compiler-rt/test/scudo/interface.cpp b/compiler-rt/test/scudo/interface.cpp
index f9353066efa..55de174322b 100644
--- a/compiler-rt/test/scudo/interface.cpp
+++ b/compiler-rt/test/scudo/interface.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_scudo %s -o %t
+// RUN: %clang_scudo %s -lstdc++ -o %t
 // RUN: %run %t 2>&1
 
 // Tests that the sanitizer interface functions behave appropriately.
diff --git a/compiler-rt/test/scudo/lit.cfg b/compiler-rt/test/scudo/lit.cfg
index 4eff2ce2191..b0476303cc1 100644
--- a/compiler-rt/test/scudo/lit.cfg
+++ b/compiler-rt/test/scudo/lit.cfg
@@ -19,9 +19,7 @@ config.suffixes = ['.c', '.cc', '.cpp']
 # C flags.
 c_flags = ([config.target_cflags] +
            ["-std=c++11",
-           "-lstdc++",
            "-lrt",
-           "-latomic",
            "-ldl",
            "-pthread",
            "-fPIE",
diff --git a/compiler-rt/test/scudo/malloc.cpp b/compiler-rt/test/scudo/malloc.cpp
index cafc744a20c..fbe57a8cbab 100644
--- a/compiler-rt/test/scudo/malloc.cpp
+++ b/compiler-rt/test/scudo/malloc.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_scudo %s -o %t
+// RUN: %clang_scudo %s -lstdc++ -o %t
 // RUN: %run %t 2>&1
 
 // Tests that a regular workflow of allocation, memory fill and free works as
diff --git a/compiler-rt/test/scudo/realloc.cpp b/compiler-rt/test/scudo/realloc.cpp
index cc44595001f..d34e356fb52 100644
--- a/compiler-rt/test/scudo/realloc.cpp
+++ b/compiler-rt/test/scudo/realloc.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_scudo %s -o %t
+// RUN: %clang_scudo %s -lstdc++ -o %t
 // RUN:     %run %t pointers 2>&1
 // RUN:     %run %t contents 2>&1
 // RUN: not %run %t memalign 2>&1 | FileCheck %s