ARM: Optimize stubs for incremental marking.

src/arm/code-stubs-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6667 matching lines @@
   if (remembered_set_action_ == EMIT_REMEMBERED_SET) {
     Label dont_need_remembered_set;
 
     __ ldr(regs_.scratch0(), MemOperand(regs_.address(), 0));
     __ JumpIfNotInNewSpace(regs_.scratch0(),
                            regs_.scratch0(),
                            &dont_need_remembered_set);
 
     __ CheckPageFlag(regs_.object(),
                      regs_.scratch0(),
-                     MemoryChunk::SCAN_ON_SCAVENGE,
+                     1 << MemoryChunk::SCAN_ON_SCAVENGE,
                      ne,
                      &dont_need_remembered_set);
 
     // First notify the incremental marker if necessary, then update the
     // remembered set.
     CheckNeedsToInformIncrementalMarker(
-        masm, kUpdateRememberedSetOnNoNeedToInformIncrementalMarker);
+        masm, kUpdateRememberedSetOnNoNeedToInformIncrementalMarker, mode);
     InformIncrementalMarker(masm, mode);
     regs_.Restore(masm);
     __ RememberedSetHelper(
         address_, value_, save_fp_regs_mode_, MacroAssembler::kReturnAtEnd);
 
     __ bind(&dont_need_remembered_set);
   }
 
   CheckNeedsToInformIncrementalMarker(
-      masm, kReturnOnNoNeedToInformIncrementalMarker);
+      masm, kReturnOnNoNeedToInformIncrementalMarker, mode);
   InformIncrementalMarker(masm, mode);
   regs_.Restore(masm);
   __ Ret();
 }
 
 
 void RecordWriteStub::InformIncrementalMarker(MacroAssembler* masm, Mode mode) {
   regs_.SaveCallerSaveRegisters(masm, save_fp_regs_mode_);
   int argument_count = 3;
   __ PrepareCallCFunction(argument_count, regs_.scratch0());
@@ skipping 24 matching lines @@
         ExternalReference::incremental_marking_record_write_function(
             masm->isolate()),
         argument_count);
   }
   regs_.RestoreCallerSaveRegisters(masm, save_fp_regs_mode_);
 }
 
 
 void RecordWriteStub::CheckNeedsToInformIncrementalMarker(
     MacroAssembler* masm,
-    OnNoNeedToInformIncrementalMarker on_no_need) {
+    OnNoNeedToInformIncrementalMarker on_no_need,
+    Mode mode) {
   Label on_black;
+  Label need_incremental;
+  Label need_incremental_pop_scratch;
 
   // Let's look at the color of the object:  If it is not black we don't have
   // to inform the incremental marker.
   __ JumpIfBlack(regs_.object(), regs_.scratch0(), regs_.scratch1(), &on_black);
 
   regs_.Restore(masm);
   if (on_no_need == kUpdateRememberedSetOnNoNeedToInformIncrementalMarker) {
     __ RememberedSetHelper(
         address_, value_, save_fp_regs_mode_, MacroAssembler::kReturnAtEnd);
   } else {
     __ Ret();
   }
 
   __ bind(&on_black);
 
-  // TODO(gc): Add call to EnsureNotWhite here.
+  // Get the value from the slot.
+  __ ldr(regs_.scratch0(), MemOperand(regs_.address(), 0));
+
+  if (mode == INCREMENTAL_COMPACTION) {
+    Label ensure_not_white;
+
+    __ CheckPageFlag(regs_.scratch0(),  // Contains value.
+                     regs_.scratch1(),  // Scratch.
+                     MemoryChunk::kEvacuationCandidateMask,
+                     eq,
+                     &ensure_not_white);
+
+    __ CheckPageFlag(regs_.object(),
+                     regs_.scratch1(),  // Scratch.
+                     MemoryChunk::kSkipEvacuationSlotsRecordingMask,
+                     ne,

[Erik Corry, 2011/08/16 09:29:23]

Seems like you should make this 'eq', change the label immediately below to
need_incremental and then you can get rid of the unconditional branch.

[Michael Starzinger, 2011/08/16 15:31:05]

Done.

+                     &ensure_not_white);
+
+    __ b(&need_incremental);
+
+    __ bind(&ensure_not_white);
+  }
+
+  // We need extra registers for this, so we push the object and the address
+  // register temporarily.
+  __ Push(regs_.object(), regs_.address());
+  __ EnsureNotWhite(regs_.scratch0(),  // The value.
+                    regs_.scratch1(),  // Scratch.
+                    regs_.object(),  // Scratch.
+                    regs_.address(),  // Scratch.
+                    &need_incremental_pop_scratch);
+  __ Pop(regs_.object(), regs_.address());
+
+  regs_.Restore(masm);
+  if (on_no_need == kUpdateRememberedSetOnNoNeedToInformIncrementalMarker) {
+    __ RememberedSetHelper(
+        address_, value_, save_fp_regs_mode_, MacroAssembler::kReturnAtEnd);
+  } else {
+    __ Ret();
+  }
+
+  __ bind(&need_incremental_pop_scratch);
+  __ Pop(regs_.object(), regs_.address());
+
+  __ bind(&need_incremental);
 
   // Fall through when we need to inform the incremental marker.
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM