[objects] Remove obsolete Code::prologue_offset field.

R=mvstanton@chromium.org
BUG=v8:6409

Change-Id: I9252055a395287381d2646fedc59c8c376333694
Reviewed-on: https://chromium-review.googlesource.com/652469Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47927}

src/codegen.cc

@@ -120,8 +120,8 @@ Handle<Code> CodeGenerator::MakeCodeEpilogue(TurboAssembler* tasm,
   tasm->GetCode(isolate, &desc);
   if (eh_frame_writer) eh_frame_writer->GetEhFrame(&desc);
 
-  Handle<Code> code = isolate->factory()->NewCode(
-      desc, flags, self_reference, false, info->prologue_offset());
+  Handle<Code> code =
+      isolate->factory()->NewCode(desc, flags, self_reference, false);
   isolate->counters()->total_compiled_code_size()->Increment(
       code->instruction_size());
   return code;

src/compilation-info.cc

@@ -77,7 +77,6 @@ CompilationInfo::CompilationInfo(Handle<Script> script,
       deferred_handles_(nullptr),
       dependencies_(isolate, zone),
       bailout_reason_(kNoReason),
-      prologue_offset_(Code::kPrologueOffsetNotSet),
       parameter_count_(0),
       optimization_id_(-1),
       osr_expr_stack_height_(-1),

src/compilation-info.h

@@ -202,16 +202,6 @@ class V8_EXPORT_PRIVATE CompilationInfo final {
 
   BailoutReason bailout_reason() const { return bailout_reason_; }
 
-  int prologue_offset() const {
-    DCHECK_NE(Code::kPrologueOffsetNotSet, prologue_offset_);
-    return prologue_offset_;
-  }
-
-  void set_prologue_offset(int prologue_offset) {
-    DCHECK_EQ(Code::kPrologueOffsetNotSet, prologue_offset_);
-    prologue_offset_ = prologue_offset;
-  }
-
   CompilationDependencies* dependencies() { return &dependencies_; }
 
   int optimization_id() const {
@@ -331,8 +321,6 @@ class V8_EXPORT_PRIVATE CompilationInfo final {
 
   BailoutReason bailout_reason_;
 
-  int prologue_offset_;
-
   InlinedFunctionList inlined_functions_;
 
   // Number of parameters used for compilation of stubs that require arguments.

src/compiler/code-generator.cc

@@ -142,9 +142,6 @@ void CodeGenerator::AssembleCode() {
     BailoutIfDeoptimized();
   }
 
-  // Architecture-specific, linkage-specific prologue.
-  info->set_prologue_offset(tasm()->pc_offset());
-
   // Define deoptimization literals for all inlined functions.
   DCHECK_EQ(0u, deoptimization_literals_.size());
   for (CompilationInfo::InlinedFunctionHolder& inlined :

src/factory.cc

@@ -1735,8 +1735,7 @@ Handle<Code> Factory::NewCodeRaw(int object_size, bool immovable) {
 }
 
 Handle<Code> Factory::NewCode(const CodeDesc& desc, Code::Flags flags,
-                              Handle<Object> self_ref, bool immovable,
-                              int prologue_offset) {
+                              Handle<Object> self_ref, bool immovable) {
   Handle<ByteArray> reloc_info = NewByteArray(desc.reloc_size, TENURED);
 
   bool has_unwinding_info = desc.unwinding_info != nullptr;
@@ -1773,7 +1772,6 @@ Handle<Code> Factory::NewCode(const CodeDesc& desc, Code::Flags flags,
   code->set_next_code_link(*undefined_value(), SKIP_WRITE_BARRIER);
   code->set_handler_table(*empty_fixed_array(), SKIP_WRITE_BARRIER);
   code->set_source_position_table(*empty_byte_array(), SKIP_WRITE_BARRIER);
-  code->set_prologue_offset(prologue_offset);
   code->set_constant_pool_offset(desc.instr_size - desc.constant_pool_size);
   code->set_builtin_index(-1);
   code->set_trap_handler_index(Smi::FromInt(-1));

src/factory.h

@@ -657,8 +657,7 @@ class V8_EXPORT_PRIVATE Factory final {
   // This allows generated code to reference its own Code object
   // by containing this handle.
   Handle<Code> NewCode(const CodeDesc& desc, Code::Flags flags,
-                       Handle<Object> self_reference, bool immovable = false,
-                       int prologue_offset = Code::kPrologueOffsetNotSet);
+                       Handle<Object> self_reference, bool immovable = false);
 
   Handle<Code> CopyCode(Handle<Code> code);
 

src/objects-inl.h

@@ -4846,7 +4846,6 @@ SMI_ACCESSORS(JSMessageObject, end_position, kEndPositionOffset)
 SMI_ACCESSORS(JSMessageObject, error_level, kErrorLevelOffset)
 
 INT_ACCESSORS(Code, instruction_size, kInstructionSizeOffset)
-INT_ACCESSORS(Code, prologue_offset, kPrologueOffset)
 INT_ACCESSORS(Code, constant_pool_offset, kConstantPoolOffset)
 #define CODE_ACCESSORS(name, type, offset)           \
   ACCESSORS_CHECKED2(Code, name, type, offset, true, \

src/objects.h

@@ -3683,8 +3683,6 @@ class Code: public HeapObject {
 
   static const char* Kind2String(Kind kind);
 
-  static const int kPrologueOffsetNotSet = -1;
-
 #if defined(OBJECT_PRINT) || defined(ENABLE_DISASSEMBLER)
   // Printing
   static const char* ICState2String(InlineCacheState state);
@@ -3736,11 +3734,6 @@ class Code: public HeapObject {
   // Note that storage for this field is overlapped with typefeedback_info.
   DECL_ACCESSORS(next_code_link, Object)
 
-  // [prologue_offset]: Offset of the function prologue, used for aging
-  // FUNCTIONs and OPTIMIZED_FUNCTIONs.
-  inline int prologue_offset() const;
-  inline void set_prologue_offset(int offset);
-
   // [constant_pool offset]: Offset of the constant pool.
   // Valid for FLAG_enable_embedded_constant_pool only
   inline int constant_pool_offset() const;
@@ -4013,9 +4006,7 @@ class Code: public HeapObject {
   static const int kKindSpecificFlags1Offset = kFlagsOffset + kIntSize;
   static const int kKindSpecificFlags2Offset =
       kKindSpecificFlags1Offset + kIntSize;
-  // Note: We might be able to squeeze this into the flags above.
-  static const int kPrologueOffset = kKindSpecificFlags2Offset + kIntSize;
-  static const int kConstantPoolOffset = kPrologueOffset + kIntSize;
+  static const int kConstantPoolOffset = kKindSpecificFlags2Offset + kIntSize;
   static const int kBuiltinIndexOffset =
       kConstantPoolOffset + kConstantPoolSize;
   static const int kTrapHandlerIndex = kBuiltinIndexOffset + kIntSize;

test/cctest/compiler/test-code-generator.cc

@@ -29,7 +29,6 @@ class CodeGeneratorTester : public InitializedHandleScope {
         frame_(descriptor_->CalculateFixedFrameSize()),
         generator_(&zone_, &frame_, &linkage_, &sequence_, &info_,
                    base::Optional<OsrHelper>(), kNoSourcePosition, nullptr) {
-    info_.set_prologue_offset(generator_.tasm()->pc_offset());
   }
 
   enum PushTypeFlag {