Merge "Create a scoped arena allocator and use that for LVN."

1 files changed, 126 insertions, 0 deletions

diff --git a/compiler/utils/scoped_arena_allocator.cc b/compiler/utils/scoped_arena_allocator.cc
new file mode 100644
index 0000000..ee3b07e
--- /dev/null
+++ b/compiler/utils/scoped_arena_allocator.cc
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "scoped_arena_allocator.h"
+
+#include "utils/arena_allocator.h"
+#include <memcheck/memcheck.h>
+
+namespace art {
+
+static constexpr size_t kValgrindRedZoneBytes = 8;
+
+ArenaStack::ArenaStack(ArenaPool* arena_pool)
+  : DebugStackRefCounter(),
+    stats_and_pool_(arena_pool),
+    bottom_arena_(nullptr),
+    top_arena_(nullptr),
+    top_ptr_(nullptr),
+    top_end_(nullptr),
+    running_on_valgrind_(RUNNING_ON_VALGRIND > 0) {
+}
+
+ArenaStack::~ArenaStack() {
+  stats_and_pool_.pool->FreeArenaChain(bottom_arena_);
+}
+
+MemStats ArenaStack::GetPeakStats() const {
+  DebugStackRefCounter::CheckNoRefs();
+  return MemStats("ArenaStack peak", static_cast<const TaggedStats<Peak>*>(&stats_and_pool_),
+                  bottom_arena_);
+}
+
+uint8_t* ArenaStack::AllocateFromNextArena(size_t rounded_bytes) {
+  UpdateBytesAllocated();
+  size_t allocation_size = std::max(Arena::kDefaultSize, rounded_bytes);
+  if (UNLIKELY(top_arena_ == nullptr)) {
+    top_arena_ = bottom_arena_ = stats_and_pool_.pool->AllocArena(allocation_size);
+    top_arena_->next_ = nullptr;
+  } else if (top_arena_->next_ != nullptr && top_arena_->next_->Size() >= allocation_size) {
+    top_arena_ = top_arena_->next_;
+  } else {
+    Arena* tail = top_arena_->next_;
+    top_arena_->next_ = stats_and_pool_.pool->AllocArena(allocation_size);
+    top_arena_ = top_arena_->next_;
+    top_arena_->next_ = tail;
+  }
+  top_end_ = top_arena_->End();
+  // top_ptr_ shall be updated by ScopedArenaAllocator.
+  return top_arena_->Begin();
+}
+
+void ArenaStack::UpdatePeakStatsAndRestore(const ArenaAllocatorStats& restore_stats) {
+  if (PeakStats()->BytesAllocated() < CurrentStats()->BytesAllocated()) {
+    PeakStats()->Copy(*CurrentStats());
+  }
+  CurrentStats()->Copy(restore_stats);
+}
+
+void ArenaStack::UpdateBytesAllocated() {
+  if (top_arena_ != nullptr) {
+    // Update how many bytes we have allocated into the arena so that the arena pool knows how
+    // much memory to zero out. Though ScopedArenaAllocator doesn't guarantee the memory is
+    // zero-initialized, the Arena may be reused by ArenaAllocator which does guarantee this.
+    size_t allocated = static_cast<size_t>(top_ptr_ - top_arena_->Begin());
+    if (top_arena_->bytes_allocated_ < allocated) {
+      top_arena_->bytes_allocated_ = allocated;
+    }
+  }
+}
+
+void* ArenaStack::AllocValgrind(size_t bytes, ArenaAllocKind kind) {
+  size_t rounded_bytes = (bytes + kValgrindRedZoneBytes + 3) & ~3;
+  uint8_t* ptr = top_ptr_;
+  if (UNLIKELY(static_cast<size_t>(top_end_ - ptr) < rounded_bytes)) {
+    ptr = AllocateFromNextArena(rounded_bytes);
+  }
+  CurrentStats()->RecordAlloc(bytes, kind);
+  top_ptr_ = ptr + rounded_bytes;
+  VALGRIND_MAKE_MEM_NOACCESS(ptr + bytes, rounded_bytes - bytes);
+  return ptr;
+}
+
+ScopedArenaAllocator::ScopedArenaAllocator(ArenaStack* arena_stack)
+  : DebugStackReference(arena_stack),
+    DebugStackRefCounter(),
+    ArenaAllocatorStats(*arena_stack->CurrentStats()),
+    arena_stack_(arena_stack),
+    mark_arena_(arena_stack->top_arena_),
+    mark_ptr_(arena_stack->top_ptr_),
+    mark_end_(arena_stack->top_end_) {
+}
+
+ScopedArenaAllocator::~ScopedArenaAllocator() {
+  Reset();
+}
+
+void ScopedArenaAllocator::Reset() {
+  DebugStackReference::CheckTop();
+  DebugStackRefCounter::CheckNoRefs();
+  arena_stack_->UpdatePeakStatsAndRestore(*this);
+  arena_stack_->UpdateBytesAllocated();
+  if (LIKELY(mark_arena_ != nullptr)) {
+    arena_stack_->top_arena_ = mark_arena_;
+    arena_stack_->top_ptr_ = mark_ptr_;
+    arena_stack_->top_end_ = mark_end_;
+  } else if (arena_stack_->bottom_arena_ != nullptr) {
+    mark_arena_ = arena_stack_->top_arena_ = arena_stack_->bottom_arena_;
+    mark_ptr_ = arena_stack_->top_ptr_ = mark_arena_->Begin();
+    mark_end_ = arena_stack_->top_end_ = mark_arena_->End();
+  }
+}
+
+}  // namespace art