[cpu-profiler] Extract rare used fields of CodeEntry to an optional object.

The RareData objects contain fields that often absent in CodeEntry'es.
They are created as needed when a corresponding field is added.
This reduces CodeEntry size on x64 by 40% from 136 to 80 bytes.

BUG=v8:7719

Change-Id: I1f3c6255aa2f228895e835b536c743396131db31
Reviewed-on: https://chromium-review.googlesource.com/1045885Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53039}

src/profiler/profile-generator-inl.h

@@ -24,8 +24,6 @@ CodeEntry::CodeEntry(CodeEventListener::LogEventsAndTags tag, const char* name,
       script_id_(v8::UnboundScript::kNoScriptId),
       position_(0),
       bailout_reason_(kEmptyBailoutReason),
-      deopt_reason_(kNoDeoptReason),
-      deopt_id_(kNoDeoptimizationId),
       line_info_(std::move(line_info)),
       instruction_start_(instruction_start) {}
 

src/profiler/profile-generator.cc

@@ -117,23 +117,26 @@ int CodeEntry::GetSourceLine(int pc_offset) const {
 
 void CodeEntry::AddInlineStack(
     int pc_offset, std::vector<std::unique_ptr<CodeEntry>> inline_stack) {
-  inline_locations_.insert(std::make_pair(pc_offset, std::move(inline_stack)));
+  EnsureRareData()->inline_locations_.insert(
+      std::make_pair(pc_offset, std::move(inline_stack)));
 }
 
 const std::vector<std::unique_ptr<CodeEntry>>* CodeEntry::GetInlineStack(
     int pc_offset) const {
-  auto it = inline_locations_.find(pc_offset);
-  return it != inline_locations_.end() ? &it->second : nullptr;
+  if (!rare_data_) return nullptr;
+  auto it = rare_data_->inline_locations_.find(pc_offset);
+  return it != rare_data_->inline_locations_.end() ? &it->second : nullptr;
 }
 
 void CodeEntry::AddDeoptInlinedFrames(
     int deopt_id, std::vector<CpuProfileDeoptFrame> inlined_frames) {
-  deopt_inlined_frames_.insert(
+  EnsureRareData()->deopt_inlined_frames_.insert(
       std::make_pair(deopt_id, std::move(inlined_frames)));
 }
 
 bool CodeEntry::HasDeoptInlinedFramesFor(int deopt_id) const {
-  return deopt_inlined_frames_.find(deopt_id) != deopt_inlined_frames_.end();
+  return rare_data_ && rare_data_->deopt_inlined_frames_.find(deopt_id) !=
+                           rare_data_->deopt_inlined_frames_.end();
 }
 
 void CodeEntry::FillFunctionInfo(SharedFunctionInfo* shared) {
@@ -148,17 +151,24 @@ CpuProfileDeoptInfo CodeEntry::GetDeoptInfo() {
   DCHECK(has_deopt_info());
 
   CpuProfileDeoptInfo info;
-  info.deopt_reason = deopt_reason_;
-  DCHECK_NE(kNoDeoptimizationId, deopt_id_);
-  if (deopt_inlined_frames_.find(deopt_id_) == deopt_inlined_frames_.end()) {
+  info.deopt_reason = rare_data_->deopt_reason_;
+  DCHECK_NE(kNoDeoptimizationId, rare_data_->deopt_id_);
+  if (rare_data_->deopt_inlined_frames_.find(rare_data_->deopt_id_) ==
+      rare_data_->deopt_inlined_frames_.end()) {
     info.stack.push_back(CpuProfileDeoptFrame(
         {script_id_, static_cast<size_t>(std::max(0, position()))}));
   } else {
-    info.stack = deopt_inlined_frames_[deopt_id_];
+    info.stack = rare_data_->deopt_inlined_frames_[rare_data_->deopt_id_];
   }
   return info;
 }
 
+CodeEntry::RareData* CodeEntry::EnsureRareData() {
+  if (!rare_data_) {
+    rare_data_.reset(new RareData());
+  }
+  return rare_data_.get();
+}
 
 void ProfileNode::CollectDeoptInfo(CodeEntry* entry) {
   deopt_infos_.push_back(entry->GetDeoptInfo());

src/profiler/profile-generator.h

@@ -37,7 +37,6 @@ class SourcePositionTable : public Malloced {
   DISALLOW_COPY_AND_ASSIGN(SourcePositionTable);
 };
 
-
 class CodeEntry {
  public:
   // CodeEntry doesn't own name strings, just references them.
@@ -64,14 +63,19 @@ class CodeEntry {
 
   void set_deopt_info(const char* deopt_reason, int deopt_id) {
     DCHECK(!has_deopt_info());
-    deopt_reason_ = deopt_reason;
-    deopt_id_ = deopt_id;
+    RareData* rare_data = EnsureRareData();
+    rare_data->deopt_reason_ = deopt_reason;
+    rare_data->deopt_id_ = deopt_id;
   }
   CpuProfileDeoptInfo GetDeoptInfo();
-  bool has_deopt_info() const { return deopt_id_ != kNoDeoptimizationId; }
+  bool has_deopt_info() const {
+    return rare_data_ && rare_data_->deopt_id_ != kNoDeoptimizationId;
+  }
   void clear_deopt_info() {
-    deopt_reason_ = kNoDeoptReason;
-    deopt_id_ = kNoDeoptimizationId;
+    if (!rare_data_) return;
+    // TODO(alph): Clear rare_data_ if that was the only field in use.
+    rare_data_->deopt_reason_ = kNoDeoptReason;
+    rare_data_->deopt_id_ = kNoDeoptimizationId;
   }
 
   void FillFunctionInfo(SharedFunctionInfo* shared);
@@ -120,6 +124,16 @@ class CodeEntry {
   }
 
  private:
+  struct RareData {
+    const char* deopt_reason_ = kNoDeoptReason;
+    int deopt_id_ = kNoDeoptimizationId;
+    // Should be an unordered_map, but it doesn't currently work on Win & MacOS.
+    std::map<int, std::vector<std::unique_ptr<CodeEntry>>> inline_locations_;
+    std::map<int, std::vector<CpuProfileDeoptFrame>> deopt_inlined_frames_;
+  };
+
+  RareData* EnsureRareData();
+
   struct ProgramEntryCreateTrait {
     static CodeEntry* Create();
   };
@@ -153,13 +167,9 @@ class CodeEntry {
   int script_id_;
   int position_;
   const char* bailout_reason_;
-  const char* deopt_reason_;
-  int deopt_id_;
   std::unique_ptr<SourcePositionTable> line_info_;
   Address instruction_start_;
-  // Should be an unordered_map, but it doesn't currently work on Win & MacOS.
-  std::map<int, std::vector<std::unique_ptr<CodeEntry>>> inline_locations_;
-  std::map<int, std::vector<CpuProfileDeoptFrame>> deopt_inlined_frames_;
+  std::unique_ptr<RareData> rare_data_;
 
   DISALLOW_COPY_AND_ASSIGN(CodeEntry);
 };