Eliminate write barrier for global stores at compile time if value stored is a smi.

src/x64/lithium-codegen-x64.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 2037 matching lines @@
   // to update the property details in the property dictionary to mark
   // it as no longer deleted. We deoptimize in that case.
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ CompareRoot(Operand(address, 0), Heap::kTheHoleValueRootIndex);
     DeoptimizeIf(equal, instr->environment());
   }
 
   // Store the value.
   __ movq(Operand(address, 0), value);
 
-  Label smi_store;
-  __ JumpIfSmi(value, &smi_store, Label::kNear);
+  if (instr->hydrogen()->NeedsWriteBarrier()) {
+    Label smi_store;
+    HType type = instr->hydrogen()->value()->type();
+    if (!type.IsHeapNumber() && !type.IsString() && !type.IsNonPrimitive()) {
+      __ JumpIfSmi(value, &smi_store, Label::kNear);
+    }
 
-  int offset = JSGlobalPropertyCell::kValueOffset - kHeapObjectTag;
-  __ lea(object, Operand(address, -offset));
-  // Cells are always in the remembered set.
-  __ RecordWrite(object,
-                 address,
-                 value,
-                 kSaveFPRegs,
-                 OMIT_REMEMBERED_SET,
-                 OMIT_SMI_CHECK);
-  __ bind(&smi_store);
+    int offset = JSGlobalPropertyCell::kValueOffset - kHeapObjectTag;
+    __ lea(object, Operand(address, -offset));
+    // Cells are always in the remembered set.
+    __ RecordWrite(object,
+                   address,
+                   value,
+                   kSaveFPRegs,
+                   OMIT_REMEMBERED_SET,
+                   OMIT_SMI_CHECK);
+    __ bind(&smi_store);
+  }
 }
 
 
 void LCodeGen::DoStoreGlobalGeneric(LStoreGlobalGeneric* instr) {
   ASSERT(ToRegister(instr->global_object()).is(rdx));
   ASSERT(ToRegister(instr->value()).is(rax));
 
   __ Move(rcx, instr->name());
   Handle<Code> ic = instr->strict_mode()
       ? isolate()->builtins()->StoreIC_Initialize_Strict()
       : isolate()->builtins()->StoreIC_Initialize();
   CallCode(ic, RelocInfo::CODE_TARGET_CONTEXT, instr);
 }
 
 
 void LCodeGen::DoLoadContextSlot(LLoadContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register result = ToRegister(instr->result());
   __ movq(result, ContextOperand(context, instr->slot_index()));
 }
 
 
 void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
   Register context = ToRegister(instr->context());
   Register value = ToRegister(instr->value());
   __ movq(ContextOperand(context, instr->slot_index()), value);
-  if (instr->needs_write_barrier()) {
+  if (instr->hydrogen()->NeedsWriteBarrier()) {
+    HType type = instr->hydrogen()->value()->type();
+    SmiCheck check_needed =
+        type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     int offset = Context::SlotOffset(instr->slot_index());
     Register scratch = ToRegister(instr->TempAt(0));
-    __ RecordWriteContextSlot(context, offset, value, scratch, kSaveFPRegs);
+    __ RecordWriteContextSlot(context, offset, value, scratch, kSaveFPRegs,

[Vyacheslav Egorov (Chromium), 2011/10/13 14:07:57]

argument per line

+                              EMIT_REMEMBERED_SET, check_needed);
   }
 }
 
 
 void LCodeGen::DoLoadNamedField(LLoadNamedField* instr) {
   Register object = ToRegister(instr->InputAt(0));
   Register result = ToRegister(instr->result());
   if (instr->hydrogen()->is_in_object()) {
     __ movq(result, FieldOperand(object, instr->hydrogen()->offset()));
   } else {
@@ skipping 943 matching lines @@
 void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   Register object = ToRegister(instr->object());
   Register value = ToRegister(instr->value());
   int offset = instr->offset();
 
   if (!instr->transition().is_null()) {
     __ Move(FieldOperand(object, HeapObject::kMapOffset), instr->transition());
   }
 
   // Do the store.
+  HType type = instr->hydrogen()->value()->type();
+  SmiCheck check_needed =
+      type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
   if (instr->is_in_object()) {
     __ movq(FieldOperand(object, offset), value);
-    if (instr->needs_write_barrier()) {
+    if (instr->hydrogen()->NeedsWriteBarrier()) {
       Register temp = ToRegister(instr->TempAt(0));
       // Update the write barrier for the object for in-object properties.
-      __ RecordWriteField(object, offset, value, temp, kSaveFPRegs);
+      __ RecordWriteField(object, offset, value, temp, kSaveFPRegs,

[Vyacheslav Egorov (Chromium), 2011/10/13 14:07:57]

argument per line

+                          EMIT_REMEMBERED_SET, check_needed);
     }
   } else {
     Register temp = ToRegister(instr->TempAt(0));
     __ movq(temp, FieldOperand(object, JSObject::kPropertiesOffset));
     __ movq(FieldOperand(temp, offset), value);
-    if (instr->needs_write_barrier()) {
+    if (instr->hydrogen()->NeedsWriteBarrier()) {
       // Update the write barrier for the properties array.
       // object is used as a scratch register.
-      __ RecordWriteField(temp, offset, value, object, kSaveFPRegs);
+      __ RecordWriteField(temp, offset, value, object, kSaveFPRegs,

[Vyacheslav Egorov (Chromium), 2011/10/13 14:07:57]

argument per line

+                          EMIT_REMEMBERED_SET, check_needed);
     }
   }
 }
 
 
 void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
   ASSERT(ToRegister(instr->object()).is(rdx));
   ASSERT(ToRegister(instr->value()).is(rax));
 
   __ Move(rcx, instr->hydrogen()->name());
@@ skipping 86 matching lines @@
     __ movq(FieldOperand(elements, offset), value);
   } else {
     __ movq(FieldOperand(elements,
                          key,
                          times_pointer_size,
                          FixedArray::kHeaderSize),
             value);
   }
 
   if (instr->hydrogen()->NeedsWriteBarrier()) {
+    HType type = instr->hydrogen()->value()->type();
+    SmiCheck check_needed =
+        type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     // Compute address of modified element and store it into key register.
     __ lea(key, FieldOperand(elements,
                              key,
                              times_pointer_size,
                              FixedArray::kHeaderSize));
-    __ RecordWrite(elements, key, value, kSaveFPRegs);
+    __ RecordWrite(elements, key, value, kSaveFPRegs,

[Vyacheslav Egorov (Chromium), 2011/10/13 14:07:57]

argument per line

+                   EMIT_REMEMBERED_SET, check_needed);
   }
 }
 
 
 void LCodeGen::DoStoreKeyedFastDoubleElement(
     LStoreKeyedFastDoubleElement* instr) {
   XMMRegister value = ToDoubleRegister(instr->value());
   Label have_value;
 
   __ ucomisd(value, value);
@@ skipping 767 matching lines @@
 }
 
 
 void LCodeGen::DoTypeofIsAndBranch(LTypeofIsAndBranch* instr) {
   Register input = ToRegister(instr->InputAt(0));
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
   Label* true_label = chunk_->GetAssemblyLabel(true_block);
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
-  Condition final_branch_condition = EmitTypeofIs(true_label,
-                                                  false_label,
-                                                  input,
-                                                  instr->type_literal());
-
-  EmitBranch(true_block, false_block, final_branch_condition);
+  Condition final_branch_condition =
+      EmitTypeofIs(true_label, false_label, input, instr->type_literal());
+  if (final_branch_condition != no_condition) {
+    EmitBranch(true_block, false_block, final_branch_condition);
+  }
 }
 
 
 Condition LCodeGen::EmitTypeofIs(Label* true_label,
                                  Label* false_label,
                                  Register input,
                                  Handle<String> type_name) {
   Condition final_branch_condition = no_condition;
   if (type_name->Equals(heap()->number_symbol())) {
     __ JumpIfSmi(input, true_label);
@@ skipping 47 matching lines @@
     __ CmpObjectType(input, FIRST_NONCALLABLE_SPEC_OBJECT_TYPE, input);
     __ j(below, false_label);
     __ CmpInstanceType(input, LAST_NONCALLABLE_SPEC_OBJECT_TYPE);
     __ j(above, false_label);
     // Check for undetectable objects => false.
     __ testb(FieldOperand(input, Map::kBitFieldOffset),
              Immediate(1 << Map::kIsUndetectable));
     final_branch_condition = zero;
 
   } else {
-    final_branch_condition = never;
     __ jmp(false_label);
   }
 
   return final_branch_condition;
 }
 
 
 void LCodeGen::DoIsConstructCallAndBranch(LIsConstructCallAndBranch* instr) {
   Register temp = ToRegister(instr->TempAt(0));
   int true_block = chunk_->LookupDestination(instr->true_block_id());
@@ skipping 134 matching lines @@
   RegisterEnvironmentForDeoptimization(environment);
   ASSERT(osr_pc_offset_ == -1);
   osr_pc_offset_ = masm()->pc_offset();
 }
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64