[v8-dev] Avoid write-barriers when initializing newly created Code object. (issue 8365029)

Fri, 21 Oct 2011 02:55:25 -0700 

Reviewers: Erik Corry,

Description:
Avoid write-barriers when initializing newly created Code object.

[email protected]


Please review this at http://codereview.chromium.org/8365029/

SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge

Affected files:
  M src/assembler.h
  M src/ia32/assembler-ia32-inl.h
  M src/objects.cc


Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 0b6db7636c4f3f53358384a66df90892bb1089c8..5b7136375916137d09ec1404e56c476f4f2ea762 100644 
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -279,14 +279,17 @@ class RelocInfo BASE_EMBEDDED {
   // this relocation applies to;
   // can only be called if IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY
   INLINE(Address target_address());
-  INLINE(void set_target_address(Address target));
+  INLINE(void set_target_address(Address target,
+ WriteBarrierMode mode = UPDATE_WRITE_BARRIER)); 
   INLINE(Object* target_object());
   INLINE(Handle<Object> target_object_handle(Assembler* origin));
   INLINE(Object** target_object_address());
-  INLINE(void set_target_object(Object* target));
+  INLINE(void set_target_object(Object* target,
+ WriteBarrierMode mode = UPDATE_WRITE_BARRIER)); 
   INLINE(JSGlobalPropertyCell* target_cell());
   INLINE(Handle<JSGlobalPropertyCell> target_cell_handle());
-  INLINE(void set_target_cell(JSGlobalPropertyCell* cell));
+  INLINE(void set_target_cell(JSGlobalPropertyCell* cell,
+ WriteBarrierMode mode = UPDATE_WRITE_BARRIER)); 


   // Read the address of the word containing the target_address in an
Index: src/ia32/assembler-ia32-inl.h
diff --git a/src/ia32/assembler-ia32-inl.h b/src/ia32/assembler-ia32-inl.h
index 446aa3e2de7b684747155f01dea41e6ec6882132..2e9fcb6c54d2c23859d5593db994f668c0dce08e 100644 
--- a/src/ia32/assembler-ia32-inl.h
+++ b/src/ia32/assembler-ia32-inl.h
@@ -88,10 +88,10 @@ int RelocInfo::target_address_size() {
 }


-void RelocInfo::set_target_address(Address target) {
+void RelocInfo::set_target_address(Address target, WriteBarrierMode mode) {
   Assembler::set_target_address_at(pc_, target);
   ASSERT(IsCodeTarget(rmode_) || rmode_ == RUNTIME_ENTRY);
-  if (host() != NULL && IsCodeTarget(rmode_)) {
+ if (mode == UPDATE_WRITE_BARRIER && host() != NULL && IsCodeTarget(rmode_)) { 
     Object* target_code = Code::GetCodeFromTargetAddress(target);
     host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
         host(), this, HeapObject::cast(target_code));
@@ -117,11 +117,13 @@ Object** RelocInfo::target_object_address() {
 }


-void RelocInfo::set_target_object(Object* target) {
+void RelocInfo::set_target_object(Object* target, WriteBarrierMode mode) {
   ASSERT(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
   Memory::Object_at(pc_) = target;
   CPU::FlushICache(pc_, sizeof(Address));
-  if (host() != NULL && target->IsHeapObject()) {
+  if (mode == UPDATE_WRITE_BARRIER &&
+      host() != NULL &&
+      target->IsHeapObject()) {
     host()->GetHeap()->incremental_marking()->RecordWrite(
         host(), &Memory::Object_at(pc_), HeapObject::cast(target));
   }
@@ -151,12 +153,13 @@ JSGlobalPropertyCell* RelocInfo::target_cell() {
 }


-void RelocInfo::set_target_cell(JSGlobalPropertyCell* cell) {
+void RelocInfo::set_target_cell(JSGlobalPropertyCell* cell,
+                                WriteBarrierMode mode) {
   ASSERT(rmode_ == RelocInfo::GLOBAL_PROPERTY_CELL);
   Address address = cell->address() + JSGlobalPropertyCell::kValueOffset;
   Memory::Address_at(pc_) = address;
   CPU::FlushICache(pc_, sizeof(Address));
-  if (host() != NULL) {
+  if (mode == UPDATE_WRITE_BARRIER && host() != NULL) {
// TODO(1550) We are passing NULL as a slot because cell can never be on 
     // evacuation candidate.
     host()->GetHeap()->incremental_marking()->RecordWrite(
Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index daaed525cc3b9f21255640a1cab9cf042f698055..b3178fa83c49cddcb0789662da9ff3e02af27a60 100644 
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -7655,6 +7655,8 @@ void Code::Relocate(intptr_t delta) {


 void Code::CopyFrom(const CodeDesc& desc) {
+  ASSERT(Marking::Color(this) == Marking::WHITE_OBJECT);
+
   // copy code
   memmove(instruction_start(), desc.buffer, desc.instr_size);

@@ -7674,16 +7676,17 @@ void Code::CopyFrom(const CodeDesc& desc) {
     RelocInfo::Mode mode = it.rinfo()->rmode();
     if (mode == RelocInfo::EMBEDDED_OBJECT) {
       Handle<Object> p = it.rinfo()->target_object_handle(origin);
-      it.rinfo()->set_target_object(*p);
+      it.rinfo()->set_target_object(*p, SKIP_WRITE_BARRIER);
     } else if (mode == RelocInfo::GLOBAL_PROPERTY_CELL) {
Handle<JSGlobalPropertyCell> cell = it.rinfo()->target_cell_handle(); 
-      it.rinfo()->set_target_cell(*cell);
+      it.rinfo()->set_target_cell(*cell, SKIP_WRITE_BARRIER);
     } else if (RelocInfo::IsCodeTarget(mode)) {
       // rewrite code handles in inline cache targets to direct
       // pointers to the first instruction in the code object
       Handle<Object> p = it.rinfo()->target_object_handle(origin);
       Code* code = Code::cast(*p);
-      it.rinfo()->set_target_address(code->instruction_start());
+      it.rinfo()->set_target_address(code->instruction_start(),
+                                     SKIP_WRITE_BARRIER);
     } else {
       it.rinfo()->apply(delta);
     }


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