Parallel marking.

runtime/vm/raw_object.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_RAW_OBJECT_H_
 #define VM_RAW_OBJECT_H_
 
 #include "platform/assert.h"
 #include "vm/atomic.h"
 #include "vm/globals.h"
@@ skipping 326 matching lines @@
   }
   void SetMarkBitUnsynchronized() {
     ASSERT(!IsMarked());
     uword tags = ptr()->tags_;
     ptr()->tags_ = MarkBit::update(true, tags);
   }
   void ClearMarkBit() {
     ASSERT(IsMarked());
     UpdateTagBit<MarkBit>(false);
   }
+  // Returns false if the bit was already set.
+  // TODO(koda): Add "must use result" annotation here, after we add support.
+  bool TryAcquireMarkBit() {
+    return TryAcquireTagBit<MarkBit>();
+  }
 
   // Support for GC watched bit.
   // TODO(iposva): Get rid of this.
   bool IsWatched() const {
     return WatchedBit::decode(ptr()->tags_);
   }
   void SetWatchedBitUnsynchronized() {
     ASSERT(!IsWatched());
     uword tags = ptr()->tags_;
     ptr()->tags_ = WatchedBit::update(true, tags);
@@ skipping 33 matching lines @@
     uword tags = ptr()->tags_;
     ptr()->tags_ = RememberedBit::update(true, tags);
   }
   void ClearRememberedBit() {
     UpdateTagBit<RememberedBit>(false);
   }
   void ClearRememberedBitUnsynchronized() {
     uword tags = ptr()->tags_;
     ptr()->tags_ = RememberedBit::update(false, tags);
   }
+  // Returns false if the bit was already set.
+  // TODO(koda): Add "must use result" annotation here, after we add support.
+  bool TryAcquireRememberedBit() {
+    return TryAcquireTagBit<RememberedBit>();
+  }
 
   bool IsDartInstance() {
     return (!IsHeapObject() || (GetClassId() >= kInstanceCid));
   }
   bool IsFreeListElement() {
     return ((GetClassId() == kFreeListElement));
   }
   bool IsScript() {
     return ((GetClassId() == kScriptCid));
   }
@@ skipping 97 matching lines @@
     uword tags = ptr()->tags_;
     uword old_tags;
     do {
       old_tags = tags;
       uword new_tags = TagBitField::update(value, old_tags);
       tags = AtomicOperations::CompareAndSwapWord(
           &ptr()->tags_, old_tags, new_tags);
     } while (tags != old_tags);
   }
 
+  template<class TagBitField>
+  bool TryAcquireTagBit() {
+    uword tags = ptr()->tags_;
+    uword old_tags;
+    do {
+      old_tags = tags;
+      if (TagBitField::decode(tags)) return false;
+      uword new_tags = TagBitField::update(true, old_tags);
+      tags = AtomicOperations::CompareAndSwapWord(
+          &ptr()->tags_, old_tags, new_tags);
+    } while (tags != old_tags);
+    return true;
+  }
+
   // All writes to heap objects should ultimately pass through one of the
   // methods below or their counterparts in Object, to ensure that the
   // write barrier is correctly applied.
 
   template<typename type>
   void StorePointer(type const* addr, type value) {
 #if defined(DEBUG)
     ValidateOverwrittenPointer(*addr);
 #endif  // DEBUG
     VerifiedMemory::Write(const_cast<type*>(addr), value);
@@ skipping 40 matching lines @@
   friend class Double;
   friend class FreeListElement;
   friend class Function;
   friend class GCMarker;
   friend class ExternalTypedData;
   friend class ForwardList;
   friend class GrowableObjectArray;  // StorePointer
   friend class Heap;
   friend class HeapMapAsJSONVisitor;
   friend class ClassStatsVisitor;
-  friend class MarkingVisitor;
+  template<bool> friend class MarkingVisitorBase;
   friend class Mint;
   friend class Object;
   friend class OneByteString;  // StoreSmi
   friend class RawExternalTypedData;
   friend class RawInstructions;
   friend class RawInstance;
   friend class RawTypedData;
   friend class Scavenger;
   friend class ScavengerVisitor;
   friend class SizeExcludingClassVisitor;  // GetClassId
@@ skipping 452 matching lines @@
   // PC offsets for code patching.
   int32_t entry_patch_pc_offset_;
   int32_t patch_code_pc_offset_;
   int32_t lazy_deopt_pc_offset_;
 
   // Variable length data follows here.
   int32_t* data() { OPEN_ARRAY_START(int32_t, int32_t); }
   const int32_t* data() const { OPEN_ARRAY_START(int32_t, int32_t); }
 
   friend class Function;
-  friend class MarkingVisitor;
+  template<bool> friend class MarkingVisitorBase;
   friend class SkippedCodeFunctions;
   friend class StackFrame;
 };
 
 
 class RawObjectPool : public RawObject {
   RAW_HEAP_OBJECT_IMPLEMENTATION(ObjectPool);
 
   intptr_t length_;
   RawTypedData* info_array_;
@@ skipping 32 matching lines @@
 
   // Private helper function used while visiting stack frames. The
   // code which iterates over dart frames is also called during GC and
   // is not allowed to create handles.
   static bool ContainsPC(RawObject* raw_obj, uword pc);
 
   friend class RawCode;
   friend class RawFunction;
   friend class Code;
   friend class StackFrame;
-  friend class MarkingVisitor;
+  template<bool> friend class MarkingVisitorBase;
   friend class SkippedCodeFunctions;
   friend class Function;
   friend class InstructionsReader;
   friend class InstructionsWriter;
 };
 
 
 class RawPcDescriptors : public RawObject {
  public:
   enum Kind {
@@ skipping 856 matching lines @@
     return reinterpret_cast<RawObject**>(&ptr()->key_);
   }
   RawObject* key_;
   RawObject* value_;
   RawObject** to() {
     return reinterpret_cast<RawObject**>(&ptr()->value_);
   }
 
   friend class DelaySet;
   friend class GCMarker;
-  friend class MarkingVisitor;
+  template<bool> friend class MarkingVisitorBase;
   friend class Scavenger;
   friend class ScavengerVisitor;
 };
 
 // MirrorReferences are used by mirrors to hold reflectees that are VM
 // internal objects, such as libraries, classes, functions or types.
 class RawMirrorReference : public RawInstance {
   RAW_HEAP_OBJECT_IMPLEMENTATION(MirrorReference);
 
   RawObject** from() {
@@ skipping 240 matching lines @@
   COMPILE_ASSERT(kExternalTypedDataInt8ArrayCid ==
                  kTypedDataInt8ArrayViewCid + 15);
   COMPILE_ASSERT(kByteBufferCid == kExternalTypedDataInt8ArrayCid + 14);
   COMPILE_ASSERT(kNullCid == kByteBufferCid + 1);
   return (kNullCid - kTypedDataInt8ArrayCid);
 }
 
 }  // namespace dart
 
 #endif  // VM_RAW_OBJECT_H_