Migrate instance of deprecated maps in HCheckMaps.

src/ia32/lithium-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
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 //
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@@ skipping 2043 matching lines @@
   // want the value in a register.  If the target gets promoted before we
   // emit code, we will still get the register but will do an immediate
   // compare instead of the cell compare.  This is safe.
   LOperand* value = instr->target_in_new_space()
       ? UseRegisterAtStart(instr->value()) : UseAtStart(instr->value());
   return AssignEnvironment(new(zone()) LCheckFunction(value));
 }
 
 
 LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
+  LOperand* context = NULL;
   LOperand* value = NULL;
-  if (!instr->CanOmitMapChecks()) value = UseRegisterAtStart(instr->value());
-  LCheckMaps* result = new(zone()) LCheckMaps(value);
-  if (instr->CanOmitMapChecks()) return result;
-  return AssignEnvironment(result);
+  if (!instr->CanOmitMapChecks()) {
+    value = UseRegisterAtStart(instr->value());
+    if (instr->has_migration_target()) {
+      // The context is not actually required for instance migration, so clobber
+      // the context register to Smi::FromInt(0).
+      HConstant* clobber_value = graph()->GetConstant0();
+      context = UseConstant(clobber_value);

[danno, 2013/08/05 14:36:59]

I don't think you need any of this new logic, do you? The context register isn't
used, the code can stay the same, right?

[Toon Verwaest, 2013/08/05 15:03:26]

Done.

+      info()->MarkAsDeferredCalling();
+    }
+  }
+  LCheckMaps* result = new(zone()) LCheckMaps(context, value);
+  if (!instr->CanOmitMapChecks()) {
+    AssignEnvironment(result);
+    if (instr->has_migration_target()) return AssignPointerMap(result);
+  }
+  return result;
 }
 
 
 LInstruction* LChunkBuilder::DoClampToUint8(HClampToUint8* instr) {
   HValue* value = instr->value();
   Representation input_rep = value->representation();
   if (input_rep.IsDouble()) {
     LOperand* reg = UseRegister(value);
     return DefineFixed(new(zone()) LClampDToUint8(reg), eax);
   } else if (input_rep.IsInteger32()) {
@@ skipping 657 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32