Move IncrementalRecordWrite to a stub.

src/incremental-marking.cc

Index: src/incremental-marking.cc
diff --git a/src/incremental-marking.cc b/src/incremental-marking.cc
index 465f5edb05167f8b445f6c63d2eeeccca15547b1..eb2356f920476fd50b38ec158d802852f3082614 100644
--- a/src/incremental-marking.cc
+++ b/src/incremental-marking.cc
@@ -29,6 +29,7 @@
 
 #include "incremental-marking.h"
 
+#include "code-stubs.h"
 
 namespace v8 {
 namespace internal {
@@ -122,6 +123,45 @@ static void ClearMarkbits() {
   }
 #endif
 
+bool IncrementalMarking::WorthActivating() {
+#ifndef DEBUG
+  static const intptr_t kActivationThreshold = 20*MB;
+#else
+  static const intptr_t kActivationThreshold = 0;

[Erik Corry, 2011/03/02 12:34:06]

Perhaps worth setting this to some low level so that some debug tests run with
incremental marking and some without.

[Vyacheslav Egorov (Chromium), 2011/03/02 15:11:32]

For now let's always resort to incremental marking to get test coverage.
I have added todo

+#endif
+
+  return FLAG_incremental_marking &&
+      Heap::PromotedSpaceSize() > kActivationThreshold;
+}
+
+
+static void PatchStubs(bool enable) {

[Erik Corry, 2011/03/02 12:34:06]

This should be called something that reveals what sort of stubs it patches.

[Vyacheslav Egorov (Chromium), 2011/03/02 15:11:32]

Done.

+  NumberDictionary* stubs = Heap::code_stubs();
+
+

[Erik Corry, 2011/03/02 12:34:06]

Blank line.

[Vyacheslav Egorov (Chromium), 2011/03/02 15:11:32]

Done.

+  int capacity = stubs->Capacity();
+  for (int i = 0; i < capacity; i++) {
+    Object* k = stubs->KeyAt(i);
+    if (stubs->IsKey(k)) {
+      uint32_t key = NumberToUint32(k);
+
+      if (CodeStub::MajorKeyFromKey(key) ==
+          CodeStub::IncrementalMarkingRecordWrite) {
+        Object* e = stubs->ValueAt(i);
+        if (e->IsJSGlobalPropertyCell()) {
+          e = JSGlobalPropertyCell::cast(e)->value();

[Erik Corry, 2011/03/02 12:34:06]

WTF?

[Vyacheslav Egorov (Chromium), 2011/03/02 15:11:32]

Done.

+        }
+
+        if (e->IsCode()) {
+          Code* stub = Code::cast(e);
+          *stub->instruction_start() = enable ? 0x90 : 0xc3;

[Erik Corry, 2011/03/02 12:34:06]

These should be constants from assembler-ia32.h 

Also you should assert that the old value was the opposite.

[Vyacheslav Egorov (Chromium), 2011/03/02 15:11:32]

Done.

+        }
+      }
+    }
+  }
+}
+
+
 void IncrementalMarking::Start() {
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Start\n");
@@ -130,6 +170,8 @@ void IncrementalMarking::Start() {
   ASSERT(state_ == STOPPED);
   state_ = MARKING;
 
+  PatchStubs(true);
+
   // Initialize marking stack.
   marking_stack_.Initialize(Heap::new_space()->FromSpaceLow(),
                             Heap::new_space()->FromSpaceHigh());
@@ -181,6 +223,7 @@ void IncrementalMarking::Hurry() {
 void IncrementalMarking::Finalize() {
   Hurry();
   state_ = STOPPED;
+  PatchStubs(false);
   ASSERT(marking_stack_.is_empty());
 }