Revert trunk to bleeding_edge at r12484

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 1949c316cb1d9de1dfedeff644ad81417106aa2b..78e1dec51358f5aa40ff2854ffdd989452d0608f 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -2118,15 +2118,37 @@ void FullCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
   ASSERT(prop != NULL);
   ASSERT(prop->key()->AsLiteral() != NULL);
 
+  // If the assignment starts a block of assignments to the same object,
+  // change to slow case to avoid the quadratic behavior of repeatedly
+  // adding fast properties.
+  if (expr->starts_initialization_block()) {
+    __ push(result_register());
+    __ push(Operand(rsp, kPointerSize));  // Receiver is now under value.
+    __ CallRuntime(Runtime::kToSlowProperties, 1);
+    __ pop(result_register());
+  }
+
   // Record source code position before IC call.
   SetSourcePosition(expr->position());
   __ Move(rcx, prop->key()->AsLiteral()->handle());
-  __ pop(rdx);
+  if (expr->ends_initialization_block()) {
+    __ movq(rdx, Operand(rsp, 0));
+  } else {
+    __ pop(rdx);
+  }
   Handle<Code> ic = is_classic_mode()
       ? isolate()->builtins()->StoreIC_Initialize()
       : isolate()->builtins()->StoreIC_Initialize_Strict();
   CallIC(ic, RelocInfo::CODE_TARGET, expr->AssignmentFeedbackId());
 
+  // If the assignment ends an initialization block, revert to fast case.
+  if (expr->ends_initialization_block()) {
+    __ push(rax);  // Result of assignment, saved even if not needed.
+    __ push(Operand(rsp, kPointerSize));  // Receiver is under value.
+    __ CallRuntime(Runtime::kToFastProperties, 1);
+    __ pop(rax);
+    __ Drop(1);
+  }
   PrepareForBailoutForId(expr->AssignmentId(), TOS_REG);
   context()->Plug(rax);
 }
@@ -2135,8 +2157,23 @@ void FullCodeGenerator::EmitNamedPropertyAssignment(Assignment* expr) {
 void FullCodeGenerator::EmitKeyedPropertyAssignment(Assignment* expr) {
   // Assignment to a property, using a keyed store IC.
 
+  // If the assignment starts a block of assignments to the same object,
+  // change to slow case to avoid the quadratic behavior of repeatedly
+  // adding fast properties.
+  if (expr->starts_initialization_block()) {
+    __ push(result_register());
+    // Receiver is now under the key and value.
+    __ push(Operand(rsp, 2 * kPointerSize));
+    __ CallRuntime(Runtime::kToSlowProperties, 1);
+    __ pop(result_register());
+  }
+
   __ pop(rcx);
-  __ pop(rdx);
+  if (expr->ends_initialization_block()) {
+    __ movq(rdx, Operand(rsp, 0));  // Leave receiver on the stack for later.
+  } else {
+    __ pop(rdx);
+  }
   // Record source code position before IC call.
   SetSourcePosition(expr->position());
   Handle<Code> ic = is_classic_mode()
@@ -2144,6 +2181,15 @@ void FullCodeGenerator::EmitKeyedPropertyAssignment(Assignment* expr) {
       : isolate()->builtins()->KeyedStoreIC_Initialize_Strict();
   CallIC(ic, RelocInfo::CODE_TARGET, expr->AssignmentFeedbackId());
 
+  // If the assignment ends an initialization block, revert to fast case.
+  if (expr->ends_initialization_block()) {
+    __ pop(rdx);
+    __ push(rax);  // Result of assignment, saved even if not needed.
+    __ push(rdx);
+    __ CallRuntime(Runtime::kToFastProperties, 1);
+    __ pop(rax);
+  }
+
   PrepareForBailoutForId(expr->AssignmentId(), TOS_REG);
   context()->Plug(rax);
 }
@@ -2596,28 +2642,22 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ j(equal, if_false);
 
   // Look for valueOf symbol in the descriptor array, and indicate false if
-  // found. Since we omit an enumeration index check, if it is added via a
-  // transition that shares its descriptor array, this is a false positive.
-  Label entry, loop, done;
-
-  // Skip loop if no descriptors are valid.
-  __ NumberOfOwnDescriptors(rcx, rbx);
-  __ cmpq(rcx, Immediate(0));
-  __ j(equal, &done);
-
+  // found. The type is not checked, so if it is a transition it is a false
+  // negative.
   __ LoadInstanceDescriptors(rbx, rbx);
-  // rbx: descriptor array.
-  // rcx: valid entries in the descriptor array.
+  __ movq(rcx, FieldOperand(rbx, FixedArray::kLengthOffset));
+  // rbx: descriptor array
+  // rcx: length of descriptor array
   // Calculate the end of the descriptor array.
-  __ imul(rcx, rcx, Immediate(DescriptorArray::kDescriptorSize));
   SmiIndex index = masm_->SmiToIndex(rdx, rcx, kPointerSizeLog2);
   __ lea(rcx,
          Operand(
-             rbx, index.reg, index.scale, DescriptorArray::kFirstOffset));
+             rbx, index.reg, index.scale, FixedArray::kHeaderSize));
   // Calculate location of the first key name.
   __ addq(rbx, Immediate(DescriptorArray::kFirstOffset));
   // Loop through all the keys in the descriptor array. If one of these is the
   // symbol valueOf the result is false.
+  Label entry, loop;
   __ jmp(&entry);
   __ bind(&loop);
   __ movq(rdx, FieldOperand(rbx, 0));
@@ -2628,11 +2668,10 @@ void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
   __ cmpq(rbx, rcx);
   __ j(not_equal, &loop);
 
-  __ bind(&done);
   // Reload map as register rbx was used as temporary above.
   __ movq(rbx, FieldOperand(rax, HeapObject::kMapOffset));
 
-  // If a valueOf property is not found on the object check that its
+  // If a valueOf property is not found on the object check that it's
   // prototype is the un-modified String prototype. If not result is false.
   __ movq(rcx, FieldOperand(rbx, Map::kPrototypeOffset));
   __ testq(rcx, Immediate(kSmiTagMask));