Initial support for emitting unwinding information in perf jitdump.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index fac56495a0048ab66f4678fad43bce600df9050f..8e522a4363547ec2897d70fd038eb438a25b422d 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -4887,6 +4887,16 @@ inline bool Code::is_interpreter_trampoline_builtin() {
          this == *builtins->InterpreterMarkBaselineOnReturn();
 }
 
+inline bool Code::has_unwinding_info() const {
+  return HasUnwindingInfoField::decode(READ_UINT32_FIELD(this, kFlagsOffset));
+}
+
+inline void Code::set_has_unwinding_info(bool state) {
+  uint32_t previous = READ_UINT32_FIELD(this, kFlagsOffset);
+  uint32_t updated_value = HasUnwindingInfoField::update(previous, state);
+  WRITE_UINT32_FIELD(this, kFlagsOffset, updated_value);
+}
+
 inline void Code::set_is_crankshafted(bool value) {
   int previous = READ_UINT32_FIELD(this, kKindSpecificFlags2Offset);
   int updated = IsCrankshaftedField::update(previous, value);
@@ -6409,6 +6419,17 @@ ACCESSORS(Code, deoptimization_data, FixedArray, kDeoptimizationDataOffset)
 ACCESSORS(Code, raw_type_feedback_info, Object, kTypeFeedbackInfoOffset)
 ACCESSORS(Code, next_code_link, Object, kNextCodeLinkOffset)
 
+int Code::unwinding_info_size() const {
+  DCHECK(has_unwinding_info());
+  int field_offset = RoundUp(kHeaderSize + instruction_size(), kInt64Size);
+  return static_cast<int>(READ_UINT64_FIELD(this, field_offset));
+}
+
+void Code::set_unwinding_info_size(int value) {
+  DCHECK(has_unwinding_info());
+  int field_offset = RoundUp(kHeaderSize + instruction_size(), kInt64Size);

[rmcilroy, 2016/06/21 13:47:43]

Factor out the code to get the offset of the unwinding info size offset into a
helper function, and use it here and in unwinding_info_start()

[Stefano Sanfilippo, 2016/06/23 15:23:43]

Done.

+  WRITE_UINT64_FIELD(this, field_offset, value);
+}
 
 void Code::WipeOutHeader() {
   WRITE_FIELD(this, kRelocationInfoOffset, NULL);
@@ -6463,9 +6484,22 @@ byte* Code::instruction_end()  {
   return instruction_start() + instruction_size();
 }
 
+byte* Code::unwinding_info_start() {
+  DCHECK(has_unwinding_info());
+  return RoundUp(instruction_end(), kInt64Size) + kInt64Size;
+}
+
+byte* Code::unwinding_info_end() {
+  DCHECK(has_unwinding_info());
+  return unwinding_info_start() + unwinding_info_size();
+}
 
 int Code::body_size() {
-  return RoundUp(instruction_size(), kObjectAlignment);
+  int unpadded_body_size =
+      has_unwinding_info()
+          ? static_cast<int>(unwinding_info_end() - instruction_start())
+          : instruction_size();
+  return RoundUp(unpadded_body_size, kObjectAlignment);
 }
 
 int Code::SizeIncludingMetadata() {