Combine the incremental-marking write barrier and the remembered-set...

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
===================================================================
--- src/ia32/stub-cache-ia32.cc	(revision 7494)
+++ src/ia32/stub-cache-ia32.cc	(working copy)
@@ -1464,7 +1464,7 @@
 
     if (argc == 1) {  // Otherwise fall through to call builtin.
       Label exit, attempt_to_grow_elements;
-      Label with_write_barrier;
+      NearLabel with_write_barrier;
 
       // Get the array's length into eax and calculate new length.
       __ mov(eax, FieldOperand(edx, JSArray::kLengthOffset));
@@ -1498,17 +1498,9 @@
 
       __ bind(&with_write_barrier);
 
-      __ IncrementalMarkingRecordWrite(ebx,
-                                       ecx,
-                                       edx,
-                                       OMIT_SMI_CHECK,
-                                       PRESERVE_OBJECT,
-                                       DESTROY_VALUE,
-                                       PRESERVE_SCRATCH);
+      __ RecordWrite(ebx, edx, ecx,
+                     EMIT_REMEMBERED_SET, kDontSaveFPRegs, OMIT_SMI_CHECK);

[Vyacheslav Egorov (Chromium), 2011/04/06 11:46:40]

strange formatting

[Erik Corry, 2011/04/06 12:31:28]

Done.

 
-      __ InNewSpace(ebx, ecx, equal, &exit);
-
-      __ RecordWriteHelper(ebx, edx, ecx, kDontSaveFPRegs);
       __ ret((argc + 1) * kPointerSize);
 
       __ bind(&attempt_to_grow_elements);
@@ -1547,13 +1539,10 @@
                Immediate(Factory::the_hole_value()));
       }
 
-      __ IncrementalMarkingRecordWrite(ebx,
-                                       ecx,
-                                       edx,
-                                       INLINE_SMI_CHECK,
-                                       PRESERVE_OBJECT,
-                                       DESTROY_VALUE,
-                                       DESTROY_SCRATCH);
+      // We know the hole is in old space, so we don't need to update the
+      // remembered set.  We also know that the hole is marked black by the
+      // incremental marker, so we can omit the incremental marking record
+      // write too.

[Vyacheslav Egorov (Chromium), 2011/04/06 11:46:40]

this was not a record write for hole, it's record write for a value we push on
line 1535 

[Erik Corry, 2011/04/06 12:31:28]

Oops.  Nice catch.  Fixed.  And comment added.  This a tricky bit of code.

 
       // Restore receiver to edx as finish sequence assumes it's here.
       __ mov(edx, Operand(esp, (argc + 1) * kPointerSize));
@@ -2621,13 +2610,8 @@
   __ j(zero, &done);
 
   __ mov(ecx, eax);
-  __ IncrementalMarkingRecordWrite(ebx,
-                                   ecx,
-                                   edx,
-                                   INLINE_SMI_CHECK,
-                                   DESTROY_OBJECT,
-                                   DESTROY_VALUE,
-                                   DESTROY_SCRATCH);
+  // Cells are always in the remembered set.
+  __ RecordWrite(ebx, edx, ecx, OMIT_REMEMBERED_SET, kDontSaveFPRegs);
 
   // Return the value (register eax).
   __ bind(&done);