From 85ecac5f3f368342a7b7e2374d0eded615bdda2a Mon Sep 17 00:00:00 2001
From: Kostya Kortchinsky <kostyak@google.com>
Date: Mon, 12 Mar 2018 17:18:26 +0000
Subject: [PATCH] [sanitizer] Align & pad the allocator structures to the
 cacheline size v2

Summary:
This is a new version of D44261, which broke some builds with older gcc, as
they can't align on a constexpr, but rather require an integer (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56859) among others.

We introduce `SANITIZER_CACHE_LINE_SIZE` in `sanitizer_platform.h` to be
used in `ALIGNED` attributes instead of using directly `kCacheLineSize`.

Reviewers: alekseyshl, thakis

Reviewed By: alekseyshl

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44326

llvm-svn: 327297
---
 .../sanitizer_common/sanitizer_allocator_primary32.h  |  8 +++-----
 .../sanitizer_common/sanitizer_allocator_primary64.h  | 11 ++++++-----
 compiler-rt/lib/sanitizer_common/sanitizer_common.h   |  6 +-----
 compiler-rt/lib/sanitizer_common/sanitizer_platform.h |  8 ++++++++
 4 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
index 4e87bd7fe011..ce7b11b6295d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
@@ -266,14 +266,12 @@ class SizeClassAllocator32 {
   static const uptr kRegionSize = 1 << kRegionSizeLog;
   static const uptr kNumPossibleRegions = kSpaceSize / kRegionSize;
 
-  struct SizeClassInfo {
+  struct ALIGNED(SANITIZER_CACHE_LINE_SIZE) SizeClassInfo {
     SpinMutex mutex;
     IntrusiveList<TransferBatch> free_list;
     u32 rand_state;
-    char padding[kCacheLineSize - 2 * sizeof(uptr) -
-                 sizeof(IntrusiveList<TransferBatch>)];
   };
-  COMPILER_CHECK(sizeof(SizeClassInfo) == kCacheLineSize);
+  COMPILER_CHECK(sizeof(SizeClassInfo) % kCacheLineSize == 0);
 
   uptr ComputeRegionId(uptr mem) {
     const uptr res = mem >> kRegionSizeLog;
@@ -299,7 +297,7 @@ class SizeClassAllocator32 {
   }
 
   SizeClassInfo *GetSizeClassInfo(uptr class_id) {
-    CHECK_LT(class_id, kNumClasses);
+    DCHECK_LT(class_id, kNumClasses);
     return &size_class_info_array[class_id];
   }
 
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
index 651a64b04f2e..255981733f3d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
@@ -80,6 +80,8 @@ class SizeClassAllocator64 {
     }
     SetReleaseToOSIntervalMs(release_to_os_interval_ms);
     MapWithCallbackOrDie(SpaceEnd(), AdditionalSize());
+    // Check that the RegionInfo array is aligned on the CacheLine size.
+    DCHECK_EQ(SpaceEnd() % kCacheLineSize, 0);
   }
 
   s32 ReleaseToOSIntervalMs() const {
@@ -584,7 +586,7 @@ class SizeClassAllocator64 {
     u64 last_released_bytes;
   };
 
-  struct RegionInfo {
+  struct ALIGNED(SANITIZER_CACHE_LINE_SIZE) RegionInfo {
     BlockingMutex mutex;
     uptr num_freed_chunks;  // Number of elements in the freearray.
     uptr mapped_free_array;  // Bytes mapped for freearray.
@@ -597,12 +599,11 @@ class SizeClassAllocator64 {
     Stats stats;
     ReleaseToOsInfo rtoi;
   };
-  COMPILER_CHECK(sizeof(RegionInfo) >= kCacheLineSize);
+  COMPILER_CHECK(sizeof(RegionInfo) % kCacheLineSize == 0);
 
   RegionInfo *GetRegionInfo(uptr class_id) const {
-    CHECK_LT(class_id, kNumClasses);
-    RegionInfo *regions =
-        reinterpret_cast<RegionInfo *>(SpaceBeg() + kSpaceSize);
+    DCHECK_LT(class_id, kNumClasses);
+    RegionInfo *regions = reinterpret_cast<RegionInfo *>(SpaceEnd());
     return &regions[class_id];
   }
 
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common.h b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
index d06d74eeb019..0a92e7768987 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common.h
@@ -39,11 +39,7 @@ struct StackTrace;
 const uptr kWordSize = SANITIZER_WORDSIZE / 8;
 const uptr kWordSizeInBits = 8 * kWordSize;
 
-#if defined(__powerpc__) || defined(__powerpc64__)
-  const uptr kCacheLineSize = 128;
-#else
-  const uptr kCacheLineSize = 64;
-#endif
+const uptr kCacheLineSize = SANITIZER_CACHE_LINE_SIZE;
 
 const uptr kMaxPathLength = 4096;
 
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
index 444b0f0dd205..2fec13f3580d 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform.h
@@ -309,4 +309,12 @@
 # define SANITIZER_MADVISE_DONTNEED MADV_DONTNEED
 #endif
 
+// Older gcc have issues aligning to a constexpr, and require an integer.
+// See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56859 among others.
+#if defined(__powerpc__) || defined(__powerpc64__)
+# define SANITIZER_CACHE_LINE_SIZE 128
+#else
+# define SANITIZER_CACHE_LINE_SIZE 64
+#endif
+
 #endif // SANITIZER_PLATFORM_H