From 561228b2fa1fa7e638a10a7767df5f6f99ddaa43 Mon Sep 17 00:00:00 2001
From: Kostya Kortchinsky <kostyak@google.com>
Date: Wed, 16 May 2018 15:13:26 +0000
Subject: [PATCH] [sanitizer] Minor 32-bit primary improvements

Summary:
For the 32-bit TransferBatch:
- `SetFromArray` callers have bounds `count`, so relax the `CHECK` to `DCHECK`;
- same for `Add`;
- mark `CopyToArray` as `const`;
For the 32-bit Primary:
- `{Dea,A}llocateBatch` are only called from places that check `class_id`,
  relax the `CHECK` to `DCHECK`;
- same for `AllocateRegion`;
- remove `GetRegionBeginBySizeClass` that is not used;
- use a local variable for the random shuffle state, so that the compiler can
  use a register instead of reading and writing to the `SizeClassInfo` at every
  iteration;
For the 32-bit local cache:
- pass the count to drain instead of doing a `Min` everytime which is at times
  superfluous.

Reviewers: alekseyshl

Reviewed By: alekseyshl

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

Differential Revision: https://reviews.llvm.org/D46657

llvm-svn: 332478
---
 .../sanitizer_common/sanitizer_allocator.h    |  4 ++-
 .../sanitizer_allocator_primary32.h           | 25 ++++++++-----------
 2 files changed, 13 insertions(+), 16 deletions(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator.h
index 1f8a5800f32a..0036f80a2577 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator.h
@@ -72,8 +72,10 @@ INLINE u32 RandN(u32 *state, u32 n) { return Rand(state) % n; }  // [0, n)
 template<typename T>
 INLINE void RandomShuffle(T *a, u32 n, u32 *rand_state) {
   if (n <= 1) return;
+  u32 state = *rand_state;
   for (u32 i = n - 1; i > 0; i--)
-    Swap(a[i], a[RandN(rand_state, i + 1)]);
+    Swap(a[i], a[RandN(&state, i + 1)]);
+  *rand_state = state;
 }
 
 #include "sanitizer_allocator_size_class_map.h"
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
index 7883ed028e57..67970e95b31e 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary32.h
@@ -64,8 +64,8 @@ class SizeClassAllocator32 {
   struct TransferBatch {
     static const uptr kMaxNumCached = SizeClassMap::kMaxNumCachedHint - 2;
     void SetFromArray(void *batch[], uptr count) {
+      DCHECK_LE(count, kMaxNumCached);
       count_ = count;
-      CHECK_LE(count_, kMaxNumCached);
       for (uptr i = 0; i < count; i++)
         batch_[i] = batch[i];
     }
@@ -73,9 +73,9 @@ class SizeClassAllocator32 {
     void Clear() { count_ = 0; }
     void Add(void *ptr) {
       batch_[count_++] = ptr;
-      CHECK_LE(count_, kMaxNumCached);
+      DCHECK_LE(count_, kMaxNumCached);
     }
-    void CopyToArray(void *to_batch[]) {
+    void CopyToArray(void *to_batch[]) const {
       for (uptr i = 0, n = Count(); i < n; i++)
         to_batch[i] = batch_[i];
     }
@@ -153,7 +153,7 @@ class SizeClassAllocator32 {
 
   NOINLINE TransferBatch *AllocateBatch(AllocatorStats *stat, AllocatorCache *c,
                                         uptr class_id) {
-    CHECK_LT(class_id, kNumClasses);
+    DCHECK_LT(class_id, kNumClasses);
     SizeClassInfo *sci = GetSizeClassInfo(class_id);
     SpinMutexLock l(&sci->mutex);
     if (sci->free_list.empty()) {
@@ -168,15 +168,13 @@ class SizeClassAllocator32 {
 
   NOINLINE void DeallocateBatch(AllocatorStats *stat, uptr class_id,
                                 TransferBatch *b) {
-    CHECK_LT(class_id, kNumClasses);
+    DCHECK_LT(class_id, kNumClasses);
     CHECK_GT(b->Count(), 0);
     SizeClassInfo *sci = GetSizeClassInfo(class_id);
     SpinMutexLock l(&sci->mutex);
     sci->free_list.push_front(b);
   }
 
-  uptr GetRegionBeginBySizeClass(uptr class_id) { return 0; }
-
   bool PointerIsMine(const void *p) {
     uptr mem = reinterpret_cast<uptr>(p);
     if (mem < kSpaceBeg || mem >= kSpaceBeg + kSpaceSize)
@@ -252,12 +250,9 @@ class SizeClassAllocator32 {
       }
   }
 
-  void PrintStats() {
-  }
+  void PrintStats() {}
 
-  static uptr AdditionalSize() {
-    return 0;
-  }
+  static uptr AdditionalSize() { return 0; }
 
   typedef SizeClassMap SizeClassMapT;
   static const uptr kNumClasses = SizeClassMap::kNumClasses;
@@ -267,7 +262,7 @@ class SizeClassAllocator32 {
   static const uptr kNumPossibleRegions = kSpaceSize / kRegionSize;
 
   struct ALIGNED(SANITIZER_CACHE_LINE_SIZE) SizeClassInfo {
-    SpinMutex mutex;
+    StaticSpinMutex mutex;
     IntrusiveList<TransferBatch> free_list;
     u32 rand_state;
   };
@@ -284,8 +279,8 @@ class SizeClassAllocator32 {
   }
 
   uptr AllocateRegion(AllocatorStats *stat, uptr class_id) {
-    CHECK_LT(class_id, kNumClasses);
-    uptr res = reinterpret_cast<uptr>(MmapAlignedOrDieOnFatalError(
+    DCHECK_LT(class_id, kNumClasses);
+    const uptr res = reinterpret_cast<uptr>(MmapAlignedOrDieOnFatalError(
         kRegionSize, kRegionSize, PrimaryAllocatorName));
     if (UNLIKELY(!res))
       return 0;