Add asserts to ensure that we:

src/ia32/builtins-ia32.cc

Index: src/ia32/builtins-ia32.cc
===================================================================
--- src/ia32/builtins-ia32.cc	(revision 9277)
+++ src/ia32/builtins-ia32.cc	(working copy)
@@ -113,265 +113,271 @@
   ASSERT(!is_api_function || !count_constructions);
 
   // Enter a construct frame.
-  __ EnterConstructFrame();
+  {
+    FrameScope scope(masm, StackFrame::CONSTRUCT);
 
-  // Store a smi-tagged arguments count on the stack.
-  __ SmiTag(eax);
-  __ push(eax);
+    // Store a smi-tagged arguments count on the stack.
+    __ SmiTag(eax);
+    __ push(eax);
 
-  // Push the function to invoke on the stack.
-  __ push(edi);
+    // Push the function to invoke on the stack.
+    __ push(edi);
 
-  // Try to allocate the object without transitioning into C code. If any of the
-  // preconditions is not met, the code bails out to the runtime call.
-  Label rt_call, allocated;
-  if (FLAG_inline_new) {
-    Label undo_allocation;
+    // Try to allocate the object without transitioning into C code. If any of
+    // the preconditions is not met, the code bails out to the runtime call.
+    Label rt_call, allocated;
+    if (FLAG_inline_new) {
+      Label undo_allocation;
 #ifdef ENABLE_DEBUGGER_SUPPORT
-    ExternalReference debug_step_in_fp =
-        ExternalReference::debug_step_in_fp_address(masm->isolate());
-    __ cmp(Operand::StaticVariable(debug_step_in_fp), Immediate(0));
-    __ j(not_equal, &rt_call);
+      ExternalReference debug_step_in_fp =
+          ExternalReference::debug_step_in_fp_address(masm->isolate());
+      __ cmp(Operand::StaticVariable(debug_step_in_fp), Immediate(0));
+      __ j(not_equal, &rt_call);
 #endif
 
-    // Verified that the constructor is a JSFunction.
-    // Load the initial map and verify that it is in fact a map.
-    // edi: constructor
-    __ mov(eax, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
-    // Will both indicate a NULL and a Smi
-    __ JumpIfSmi(eax, &rt_call);
-    // edi: constructor
-    // eax: initial map (if proven valid below)
-    __ CmpObjectType(eax, MAP_TYPE, ebx);
-    __ j(not_equal, &rt_call);
+      // Verified that the constructor is a JSFunction.
+      // Load the initial map and verify that it is in fact a map.
+      // edi: constructor
+      __ mov(eax, FieldOperand(edi, JSFunction::kPrototypeOrInitialMapOffset));
+      // Will both indicate a NULL and a Smi
+      __ JumpIfSmi(eax, &rt_call);
+      // edi: constructor
+      // eax: initial map (if proven valid below)
+      __ CmpObjectType(eax, MAP_TYPE, ebx);
+      __ j(not_equal, &rt_call);
 
-    // Check that the constructor is not constructing a JSFunction (see comments
-    // in Runtime_NewObject in runtime.cc). In which case the initial map's
-    // instance type would be JS_FUNCTION_TYPE.
-    // edi: constructor
-    // eax: initial map
-    __ CmpInstanceType(eax, JS_FUNCTION_TYPE);
-    __ j(equal, &rt_call);
+      // Check that the constructor is not constructing a JSFunction (see
+      // comments in Runtime_NewObject in runtime.cc). In which case the
+      // initial map's instance type would be JS_FUNCTION_TYPE.
+      // edi: constructor
+      // eax: initial map
+      __ CmpInstanceType(eax, JS_FUNCTION_TYPE);
+      __ j(equal, &rt_call);
 
-    if (count_constructions) {
-      Label allocate;
-      // Decrease generous allocation count.
-      __ mov(ecx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
-      __ dec_b(FieldOperand(ecx, SharedFunctionInfo::kConstructionCountOffset));
-      __ j(not_zero, &allocate);
+      if (count_constructions) {
+        Label allocate;
+        // Decrease generous allocation count.
+        __ mov(ecx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
+        __ dec_b(FieldOperand(ecx,
+                              SharedFunctionInfo::kConstructionCountOffset));
+        __ j(not_zero, &allocate);
 
-      __ push(eax);
-      __ push(edi);
+        __ push(eax);
+        __ push(edi);
 
-      __ push(edi);  // constructor
-      // The call will replace the stub, so the countdown is only done once.
-      __ CallRuntime(Runtime::kFinalizeInstanceSize, 1);
+        __ push(edi);  // constructor
+        // The call will replace the stub, so the countdown is only done once.
+        __ CallRuntime(Runtime::kFinalizeInstanceSize, 1);
 
-      __ pop(edi);
-      __ pop(eax);
+        __ pop(edi);
+        __ pop(eax);
 
-      __ bind(&allocate);
-    }
+        __ bind(&allocate);
+      }
 
-    // Now allocate the JSObject on the heap.
-    // edi: constructor
-    // eax: initial map
-    __ movzx_b(edi, FieldOperand(eax, Map::kInstanceSizeOffset));
-    __ shl(edi, kPointerSizeLog2);
-    __ AllocateInNewSpace(edi, ebx, edi, no_reg, &rt_call, NO_ALLOCATION_FLAGS);
-    // Allocated the JSObject, now initialize the fields.
-    // eax: initial map
-    // ebx: JSObject
-    // edi: start of next object
-    __ mov(Operand(ebx, JSObject::kMapOffset), eax);
-    Factory* factory = masm->isolate()->factory();
-    __ mov(ecx, factory->empty_fixed_array());
-    __ mov(Operand(ebx, JSObject::kPropertiesOffset), ecx);
-    __ mov(Operand(ebx, JSObject::kElementsOffset), ecx);
-    // Set extra fields in the newly allocated object.
-    // eax: initial map
-    // ebx: JSObject
-    // edi: start of next object
-    { Label loop, entry;
-      // To allow for truncation.
-      if (count_constructions) {
-        __ mov(edx, factory->one_pointer_filler_map());
-      } else {
-        __ mov(edx, factory->undefined_value());
+      // Now allocate the JSObject on the heap.
+      // edi: constructor
+      // eax: initial map
+      __ movzx_b(edi, FieldOperand(eax, Map::kInstanceSizeOffset));
+      __ shl(edi, kPointerSizeLog2);
+      __ AllocateInNewSpace(
+          edi, ebx, edi, no_reg, &rt_call, NO_ALLOCATION_FLAGS);
+      // Allocated the JSObject, now initialize the fields.
+      // eax: initial map
+      // ebx: JSObject
+      // edi: start of next object
+      __ mov(Operand(ebx, JSObject::kMapOffset), eax);
+      Factory* factory = masm->isolate()->factory();
+      __ mov(ecx, factory->empty_fixed_array());
+      __ mov(Operand(ebx, JSObject::kPropertiesOffset), ecx);
+      __ mov(Operand(ebx, JSObject::kElementsOffset), ecx);
+      // Set extra fields in the newly allocated object.
+      // eax: initial map
+      // ebx: JSObject
+      // edi: start of next object
+      { Label loop, entry;
+        // To allow for truncation.
+        if (count_constructions) {
+          __ mov(edx, factory->one_pointer_filler_map());
+        } else {
+          __ mov(edx, factory->undefined_value());
+        }
+        __ lea(ecx, Operand(ebx, JSObject::kHeaderSize));
+        __ jmp(&entry);
+        __ bind(&loop);
+        __ mov(Operand(ecx, 0), edx);
+        __ add(Operand(ecx), Immediate(kPointerSize));
+        __ bind(&entry);
+        __ cmp(ecx, Operand(edi));
+        __ j(less, &loop);
       }
-      __ lea(ecx, Operand(ebx, JSObject::kHeaderSize));
-      __ jmp(&entry);
-      __ bind(&loop);
-      __ mov(Operand(ecx, 0), edx);
-      __ add(Operand(ecx), Immediate(kPointerSize));
-      __ bind(&entry);
-      __ cmp(ecx, Operand(edi));
-      __ j(less, &loop);
-    }
 
-    // Add the object tag to make the JSObject real, so that we can continue and
-    // jump into the continuation code at any time from now on. Any failures
-    // need to undo the allocation, so that the heap is in a consistent state
-    // and verifiable.
-    // eax: initial map
-    // ebx: JSObject
-    // edi: start of next object
-    __ or_(Operand(ebx), Immediate(kHeapObjectTag));
+      // Add the object tag to make the JSObject real, so that we can continue
+      // and jump into the continuation code at any time from now on. Any
+      // failures need to undo the allocation, so that the heap is in a
+      // consistent state and verifiable.
+      // eax: initial map
+      // ebx: JSObject
+      // edi: start of next object
+      __ or_(Operand(ebx), Immediate(kHeapObjectTag));
 
-    // Check if a non-empty properties array is needed.
-    // Allocate and initialize a FixedArray if it is.
-    // eax: initial map
-    // ebx: JSObject
-    // edi: start of next object
-    // Calculate the total number of properties described by the map.
-    __ movzx_b(edx, FieldOperand(eax, Map::kUnusedPropertyFieldsOffset));
-    __ movzx_b(ecx, FieldOperand(eax, Map::kPreAllocatedPropertyFieldsOffset));
-    __ add(edx, Operand(ecx));
-    // Calculate unused properties past the end of the in-object properties.
-    __ movzx_b(ecx, FieldOperand(eax, Map::kInObjectPropertiesOffset));
-    __ sub(edx, Operand(ecx));
-    // Done if no extra properties are to be allocated.
-    __ j(zero, &allocated);
-    __ Assert(positive, "Property allocation count failed.");
+      // Check if a non-empty properties array is needed.
+      // Allocate and initialize a FixedArray if it is.
+      // eax: initial map
+      // ebx: JSObject
+      // edi: start of next object
+      // Calculate the total number of properties described by the map.
+      __ movzx_b(edx, FieldOperand(eax, Map::kUnusedPropertyFieldsOffset));
+      __ movzx_b(ecx,
+                 FieldOperand(eax, Map::kPreAllocatedPropertyFieldsOffset));
+      __ add(edx, Operand(ecx));
+      // Calculate unused properties past the end of the in-object properties.
+      __ movzx_b(ecx, FieldOperand(eax, Map::kInObjectPropertiesOffset));
+      __ sub(edx, Operand(ecx));
+      // Done if no extra properties are to be allocated.
+      __ j(zero, &allocated);
+      __ Assert(positive, "Property allocation count failed.");
 
-    // Scale the number of elements by pointer size and add the header for
-    // FixedArrays to the start of the next object calculation from above.
-    // ebx: JSObject
-    // edi: start of next object (will be start of FixedArray)
-    // edx: number of elements in properties array
-    __ AllocateInNewSpace(FixedArray::kHeaderSize,
-                          times_pointer_size,
-                          edx,
-                          edi,
-                          ecx,
-                          no_reg,
-                          &undo_allocation,
-                          RESULT_CONTAINS_TOP);
+      // Scale the number of elements by pointer size and add the header for
+      // FixedArrays to the start of the next object calculation from above.
+      // ebx: JSObject
+      // edi: start of next object (will be start of FixedArray)
+      // edx: number of elements in properties array
+      __ AllocateInNewSpace(FixedArray::kHeaderSize,
+                            times_pointer_size,
+                            edx,
+                            edi,
+                            ecx,
+                            no_reg,
+                            &undo_allocation,
+                            RESULT_CONTAINS_TOP);
 
-    // Initialize the FixedArray.
-    // ebx: JSObject
-    // edi: FixedArray
-    // edx: number of elements
-    // ecx: start of next object
-    __ mov(eax, factory->fixed_array_map());
-    __ mov(Operand(edi, FixedArray::kMapOffset), eax);  // setup the map
-    __ SmiTag(edx);
-    __ mov(Operand(edi, FixedArray::kLengthOffset), edx);  // and length
+      // Initialize the FixedArray.
+      // ebx: JSObject
+      // edi: FixedArray
+      // edx: number of elements
+      // ecx: start of next object
+      __ mov(eax, factory->fixed_array_map());
+      __ mov(Operand(edi, FixedArray::kMapOffset), eax);  // setup the map
+      __ SmiTag(edx);
+      __ mov(Operand(edi, FixedArray::kLengthOffset), edx);  // and length
 
-    // Initialize the fields to undefined.
-    // ebx: JSObject
-    // edi: FixedArray
-    // ecx: start of next object
-    { Label loop, entry;
-      __ mov(edx, factory->undefined_value());
-      __ lea(eax, Operand(edi, FixedArray::kHeaderSize));
-      __ jmp(&entry);
-      __ bind(&loop);
-      __ mov(Operand(eax, 0), edx);
-      __ add(Operand(eax), Immediate(kPointerSize));
-      __ bind(&entry);
-      __ cmp(eax, Operand(ecx));
-      __ j(below, &loop);
-    }
+      // Initialize the fields to undefined.
+      // ebx: JSObject
+      // edi: FixedArray
+      // ecx: start of next object
+      { Label loop, entry;
+        __ mov(edx, factory->undefined_value());
+        __ lea(eax, Operand(edi, FixedArray::kHeaderSize));
+        __ jmp(&entry);
+        __ bind(&loop);
+        __ mov(Operand(eax, 0), edx);
+        __ add(Operand(eax), Immediate(kPointerSize));
+        __ bind(&entry);
+        __ cmp(eax, Operand(ecx));
+        __ j(below, &loop);
+      }
 
-    // Store the initialized FixedArray into the properties field of
-    // the JSObject
-    // ebx: JSObject
-    // edi: FixedArray
-    __ or_(Operand(edi), Immediate(kHeapObjectTag));  // add the heap tag
-    __ mov(FieldOperand(ebx, JSObject::kPropertiesOffset), edi);
+      // Store the initialized FixedArray into the properties field of
+      // the JSObject
+      // ebx: JSObject
+      // edi: FixedArray
+      __ or_(Operand(edi), Immediate(kHeapObjectTag));  // add the heap tag
+      __ mov(FieldOperand(ebx, JSObject::kPropertiesOffset), edi);
 
 
-    // Continue with JSObject being successfully allocated
-    // ebx: JSObject
-    __ jmp(&allocated);
+      // Continue with JSObject being successfully allocated
+      // ebx: JSObject
+      __ jmp(&allocated);
 
-    // Undo the setting of the new top so that the heap is verifiable. For
-    // example, the map's unused properties potentially do not match the
-    // allocated objects unused properties.
-    // ebx: JSObject (previous new top)
-    __ bind(&undo_allocation);
-    __ UndoAllocationInNewSpace(ebx);
-  }
+      // Undo the setting of the new top so that the heap is verifiable. For
+      // example, the map's unused properties potentially do not match the
+      // allocated objects unused properties.
+      // ebx: JSObject (previous new top)
+      __ bind(&undo_allocation);
+      __ UndoAllocationInNewSpace(ebx);
+    }
 
-  // Allocate the new receiver object using the runtime call.
-  __ bind(&rt_call);
-  // Must restore edi (constructor) before calling runtime.
-  __ mov(edi, Operand(esp, 0));
-  // edi: function (constructor)
-  __ push(edi);
-  __ CallRuntime(Runtime::kNewObject, 1);
-  __ mov(ebx, Operand(eax));  // store result in ebx
+    // Allocate the new receiver object using the runtime call.
+    __ bind(&rt_call);
+    // Must restore edi (constructor) before calling runtime.
+    __ mov(edi, Operand(esp, 0));
+    // edi: function (constructor)
+    __ push(edi);
+    __ CallRuntime(Runtime::kNewObject, 1);
+    __ mov(ebx, Operand(eax));  // store result in ebx
 
-  // New object allocated.
-  // ebx: newly allocated object
-  __ bind(&allocated);
-  // Retrieve the function from the stack.
-  __ pop(edi);
+    // New object allocated.
+    // ebx: newly allocated object
+    __ bind(&allocated);
+    // Retrieve the function from the stack.
+    __ pop(edi);
 
-  // Retrieve smi-tagged arguments count from the stack.
-  __ mov(eax, Operand(esp, 0));
-  __ SmiUntag(eax);
+    // Retrieve smi-tagged arguments count from the stack.
+    __ mov(eax, Operand(esp, 0));
+    __ SmiUntag(eax);
 
-  // Push the allocated receiver to the stack. We need two copies
-  // because we may have to return the original one and the calling
-  // conventions dictate that the called function pops the receiver.
-  __ push(ebx);
-  __ push(ebx);
+    // Push the allocated receiver to the stack. We need two copies
+    // because we may have to return the original one and the calling
+    // conventions dictate that the called function pops the receiver.
+    __ push(ebx);
+    __ push(ebx);
 
-  // Setup pointer to last argument.
-  __ lea(ebx, Operand(ebp, StandardFrameConstants::kCallerSPOffset));
+    // Setup pointer to last argument.
+    __ lea(ebx, Operand(ebp, StandardFrameConstants::kCallerSPOffset));
 
-  // Copy arguments and receiver to the expression stack.
-  Label loop, entry;
-  __ mov(ecx, Operand(eax));
-  __ jmp(&entry);
-  __ bind(&loop);
-  __ push(Operand(ebx, ecx, times_4, 0));
-  __ bind(&entry);
-  __ dec(ecx);
-  __ j(greater_equal, &loop);
+    // Copy arguments and receiver to the expression stack.
+    Label loop, entry;
+    __ mov(ecx, Operand(eax));
+    __ jmp(&entry);
+    __ bind(&loop);
+    __ push(Operand(ebx, ecx, times_4, 0));
+    __ bind(&entry);
+    __ dec(ecx);
+    __ j(greater_equal, &loop);
 
-  // Call the function.
-  if (is_api_function) {
-    __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
-    Handle<Code> code =
-        masm->isolate()->builtins()->HandleApiCallConstruct();
-    ParameterCount expected(0);
-    __ InvokeCode(code, expected, expected, RelocInfo::CODE_TARGET,
-                  CALL_FUNCTION, NullCallWrapper(), CALL_AS_METHOD);
-  } else {
-    ParameterCount actual(eax);
-    __ InvokeFunction(edi, actual, CALL_FUNCTION,
-                      NullCallWrapper(), CALL_AS_METHOD);
-  }
+    // Call the function.
+    if (is_api_function) {
+      __ mov(esi, FieldOperand(edi, JSFunction::kContextOffset));
+      Handle<Code> code =
+          masm->isolate()->builtins()->HandleApiCallConstruct();
+      ParameterCount expected(0);
+      __ InvokeCode(code, expected, expected, RelocInfo::CODE_TARGET,
+                    CALL_FUNCTION, NullCallWrapper(), CALL_AS_METHOD);
+    } else {
+      ParameterCount actual(eax);
+      __ InvokeFunction(edi, actual, CALL_FUNCTION,
+                        NullCallWrapper(), CALL_AS_METHOD);
+    }
 
-  // Restore context from the frame.
-  __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
+    // Restore context from the frame.
+    __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
 
-  // If the result is an object (in the ECMA sense), we should get rid
-  // of the receiver and use the result; see ECMA-262 section 13.2.2-7
-  // on page 74.
-  Label use_receiver, exit;
+    // If the result is an object (in the ECMA sense), we should get rid
+    // of the receiver and use the result; see ECMA-262 section 13.2.2-7
+    // on page 74.
+    Label use_receiver, exit;
 
-  // If the result is a smi, it is *not* an object in the ECMA sense.
-  __ JumpIfSmi(eax, &use_receiver);
+    // If the result is a smi, it is *not* an object in the ECMA sense.
+    __ JumpIfSmi(eax, &use_receiver);
 
-  // If the type of the result (stored in its map) is less than
-  // FIRST_SPEC_OBJECT_TYPE, it is not an object in the ECMA sense.
-  __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
-  __ j(above_equal, &exit);
+    // If the type of the result (stored in its map) is less than
+    // FIRST_SPEC_OBJECT_TYPE, it is not an object in the ECMA sense.
+    __ CmpObjectType(eax, FIRST_SPEC_OBJECT_TYPE, ecx);
+    __ j(above_equal, &exit);
 
-  // Throw away the result of the constructor invocation and use the
-  // on-stack receiver as the result.
-  __ bind(&use_receiver);
-  __ mov(eax, Operand(esp, 0));
+    // Throw away the result of the constructor invocation and use the
+    // on-stack receiver as the result.
+    __ bind(&use_receiver);
+    __ mov(eax, Operand(esp, 0));
 
-  // Restore the arguments count and leave the construct frame.
-  __ bind(&exit);
-  __ mov(ebx, Operand(esp, kPointerSize));  // get arguments count
-  __ LeaveConstructFrame();
+    // Restore the arguments count and leave the construct frame.
+    __ bind(&exit);
+    __ mov(ebx, Operand(esp, kPointerSize));  // Get arguments count.
 
+    // Leave construct frame.
+  }
+
   // Remove caller arguments from the stack and return.
   STATIC_ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
   __ pop(ecx);
@@ -399,57 +405,58 @@
 
 static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                              bool is_construct) {
-  // Clear the context before we push it when entering the JS frame.
+  // Clear the context before we push it when entering the internal frame.
   __ Set(esi, Immediate(0));
 
-  // Enter an internal frame.
-  __ EnterInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Load the previous frame pointer (ebx) to access C arguments
-  __ mov(ebx, Operand(ebp, 0));
+    // Load the previous frame pointer (ebx) to access C arguments
+    __ mov(ebx, Operand(ebp, 0));
 
-  // Get the function from the frame and setup the context.
-  __ mov(ecx, Operand(ebx, EntryFrameConstants::kFunctionArgOffset));
-  __ mov(esi, FieldOperand(ecx, JSFunction::kContextOffset));
+    // Get the function from the frame and setup the context.
+    __ mov(ecx, Operand(ebx, EntryFrameConstants::kFunctionArgOffset));
+    __ mov(esi, FieldOperand(ecx, JSFunction::kContextOffset));
 
-  // Push the function and the receiver onto the stack.
-  __ push(ecx);
-  __ push(Operand(ebx, EntryFrameConstants::kReceiverArgOffset));
+    // Push the function and the receiver onto the stack.
+    __ push(ecx);
+    __ push(Operand(ebx, EntryFrameConstants::kReceiverArgOffset));
 
-  // Load the number of arguments and setup pointer to the arguments.
-  __ mov(eax, Operand(ebx, EntryFrameConstants::kArgcOffset));
-  __ mov(ebx, Operand(ebx, EntryFrameConstants::kArgvOffset));
+    // Load the number of arguments and setup pointer to the arguments.
+    __ mov(eax, Operand(ebx, EntryFrameConstants::kArgcOffset));
+    __ mov(ebx, Operand(ebx, EntryFrameConstants::kArgvOffset));
 
-  // Copy arguments to the stack in a loop.
-  Label loop, entry;
-  __ Set(ecx, Immediate(0));
-  __ jmp(&entry);
-  __ bind(&loop);
-  __ mov(edx, Operand(ebx, ecx, times_4, 0));  // push parameter from argv
-  __ push(Operand(edx, 0));  // dereference handle
-  __ inc(Operand(ecx));
-  __ bind(&entry);
-  __ cmp(ecx, Operand(eax));
-  __ j(not_equal, &loop);
+    // Copy arguments to the stack in a loop.
+    Label loop, entry;
+    __ Set(ecx, Immediate(0));
+    __ jmp(&entry);
+    __ bind(&loop);
+    __ mov(edx, Operand(ebx, ecx, times_4, 0));  // push parameter from argv
+    __ push(Operand(edx, 0));  // dereference handle
+    __ inc(Operand(ecx));
+    __ bind(&entry);
+    __ cmp(ecx, Operand(eax));
+    __ j(not_equal, &loop);
 
-  // Get the function from the stack and call it.
-  __ mov(edi, Operand(esp, eax, times_4, +1 * kPointerSize));  // +1 ~ receiver
+    // Get the function from the stack and call it.
+    // kPointerSize for the receiver.
+    __ mov(edi, Operand(esp, eax, times_4, kPointerSize));
 
-  // Invoke the code.
-  if (is_construct) {
-    __ call(masm->isolate()->builtins()->JSConstructCall(),
-            RelocInfo::CODE_TARGET);
-  } else {
-    ParameterCount actual(eax);
-    __ InvokeFunction(edi, actual, CALL_FUNCTION,
-                      NullCallWrapper(), CALL_AS_METHOD);
+    // Invoke the code.
+    if (is_construct) {
+      __ call(masm->isolate()->builtins()->JSConstructCall(),
+              RelocInfo::CODE_TARGET);
+    } else {
+      ParameterCount actual(eax);
+      __ InvokeFunction(edi, actual, CALL_FUNCTION,
+                        NullCallWrapper(), CALL_AS_METHOD);
+    }
+
+    // Exit the internal frame. Notice that this also removes the empty.
+    // context and the function left on the stack by the code
+    // invocation.
   }
-
-  // Exit the JS frame. Notice that this also removes the empty
-  // context and the function left on the stack by the code
-  // invocation.
-  __ LeaveInternalFrame();
-  __ ret(1 * kPointerSize);  // remove receiver
+  __ ret(kPointerSize);  // Remove receiver.
 }
 
 
@@ -464,24 +471,24 @@
 
 
 void Builtins::Generate_LazyCompile(MacroAssembler* masm) {
-  // Enter an internal frame.
-  __ EnterInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Push a copy of the function.
-  __ push(edi);
-  // Push call kind information.
-  __ push(ecx);
+    // Push a copy of the function.
+    __ push(edi);
+    // Push call kind information.
+    __ push(ecx);
 
-  __ push(edi);  // Function is also the parameter to the runtime call.
-  __ CallRuntime(Runtime::kLazyCompile, 1);
+    __ push(edi);  // Function is also the parameter to the runtime call.
+    __ CallRuntime(Runtime::kLazyCompile, 1);
 
-  // Restore call kind information.
-  __ pop(ecx);
-  // Restore receiver.
-  __ pop(edi);
+    // Restore call kind information.
+    __ pop(ecx);
+    // Restore receiver.
+    __ pop(edi);
 
-  // Tear down temporary frame.
-  __ LeaveInternalFrame();
+    // Tear down internal frame.
+  }
 
   // Do a tail-call of the compiled function.
   __ lea(eax, FieldOperand(eax, Code::kHeaderSize));
@@ -490,24 +497,24 @@
 
 
 void Builtins::Generate_LazyRecompile(MacroAssembler* masm) {
-  // Enter an internal frame.
-  __ EnterInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Push a copy of the function onto the stack.
-  __ push(edi);
-  // Push call kind information.
-  __ push(ecx);
+    // Push a copy of the function onto the stack.
+    __ push(edi);
+    // Push call kind information.
+    __ push(ecx);
 
-  __ push(edi);  // Function is also the parameter to the runtime call.
-  __ CallRuntime(Runtime::kLazyRecompile, 1);
+    __ push(edi);  // Function is also the parameter to the runtime call.
+    __ CallRuntime(Runtime::kLazyRecompile, 1);
 
-  // Restore call kind information.
-  __ pop(ecx);
-  // Restore receiver.
-  __ pop(edi);
+    // Restore call kind information.
+    __ pop(ecx);
+    // Restore receiver.
+    __ pop(edi);
 
-  // Tear down temporary frame.
-  __ LeaveInternalFrame();
+    // Tear down internal frame.
+  }
 
   // Do a tail-call of the compiled function.
   __ lea(eax, FieldOperand(eax, Code::kHeaderSize));
@@ -517,15 +524,15 @@
 
 static void Generate_NotifyDeoptimizedHelper(MacroAssembler* masm,
                                              Deoptimizer::BailoutType type) {
-  // Enter an internal frame.
-  __ EnterInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
 
-  // Pass the function and deoptimization type to the runtime system.
-  __ push(Immediate(Smi::FromInt(static_cast<int>(type))));
-  __ CallRuntime(Runtime::kNotifyDeoptimized, 1);
+    // Pass the function and deoptimization type to the runtime system.
+    __ push(Immediate(Smi::FromInt(static_cast<int>(type))));
+    __ CallRuntime(Runtime::kNotifyDeoptimized, 1);
 
-  // Tear down temporary frame.
-  __ LeaveInternalFrame();
+    // Tear down internal frame.
+  }
 
   // Get the full codegen state from the stack and untag it.
   __ mov(ecx, Operand(esp, 1 * kPointerSize));
@@ -566,9 +573,10 @@
   // the registers without worrying about which of them contain
   // pointers. This seems a bit fragile.
   __ pushad();
-  __ EnterInternalFrame();
-  __ CallRuntime(Runtime::kNotifyOSR, 0);
-  __ LeaveInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ CallRuntime(Runtime::kNotifyOSR, 0);
+  }
   __ popad();
   __ ret(0);
 }
@@ -631,18 +639,21 @@
     __ j(above_equal, &shift_arguments);
 
     __ bind(&convert_to_object);
-    __ EnterInternalFrame();  // In order to preserve argument count.
-    __ SmiTag(eax);
-    __ push(eax);
 
-    __ push(ebx);
-    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
-    __ mov(ebx, eax);
-    __ Set(edx, Immediate(0));  // restore
+    { // In order to preserve argument count.
+      FrameScope scope(masm, StackFrame::INTERNAL);
+      __ SmiTag(eax);
+      __ push(eax);
 
-    __ pop(eax);
-    __ SmiUntag(eax);
-    __ LeaveInternalFrame();
+      __ push(ebx);
+      __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+      __ mov(ebx, eax);
+      __ Set(edx, Immediate(0));  // restore
+
+      __ pop(eax);
+      __ SmiUntag(eax);
+    }
+
     // Restore the function to edi.
     __ mov(edi, Operand(esp, eax, times_4, 1 * kPointerSize));
     __ jmp(&patch_receiver);
@@ -740,9 +751,9 @@
   static const int kArgumentsOffset = 2 * kPointerSize;
   static const int kReceiverOffset = 3 * kPointerSize;
   static const int kFunctionOffset = 4 * kPointerSize;
+{
+  FrameScope frame_scope(masm, StackFrame::INTERNAL);
 
-  __ EnterInternalFrame();
-
   __ push(Operand(ebp, kFunctionOffset));  // push this
   __ push(Operand(ebp, kArgumentsOffset));  // push arguments
   __ InvokeBuiltin(Builtins::APPLY_PREPARE, CALL_FUNCTION);
@@ -875,7 +886,7 @@
   __ InvokeFunction(edi, actual, CALL_FUNCTION,
                     NullCallWrapper(), CALL_AS_METHOD);
 
-  __ LeaveInternalFrame();
+  frame_scope.GenerateLeaveFrame();
   __ ret(3 * kPointerSize);  // remove this, receiver, and arguments
 
   // Invoke the function proxy.
@@ -888,7 +899,8 @@
   __ call(masm->isolate()->builtins()->ArgumentsAdaptorTrampoline(),
           RelocInfo::CODE_TARGET);
 
-  __ LeaveInternalFrame();
+  // Leave internal frame.
+}
   __ ret(3 * kPointerSize);  // remove this, receiver, and arguments
 }
 
@@ -1439,12 +1451,13 @@
   // Invoke the conversion builtin and put the result into ebx.
   __ bind(&convert_argument);
   __ IncrementCounter(counters->string_ctor_conversions(), 1);
-  __ EnterInternalFrame();
-  __ push(edi);  // Preserve the function.
-  __ push(eax);
-  __ InvokeBuiltin(Builtins::TO_STRING, CALL_FUNCTION);
-  __ pop(edi);
-  __ LeaveInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ push(edi);  // Preserve the function.
+    __ push(eax);
+    __ InvokeBuiltin(Builtins::TO_STRING, CALL_FUNCTION);
+    __ pop(edi);
+  }
   __ mov(ebx, eax);
   __ jmp(&argument_is_string);
 
@@ -1461,10 +1474,11 @@
   // create a string wrapper.
   __ bind(&gc_required);
   __ IncrementCounter(counters->string_ctor_gc_required(), 1);
-  __ EnterInternalFrame();
-  __ push(ebx);
-  __ CallRuntime(Runtime::kNewStringWrapper, 1);
-  __ LeaveInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ push(ebx);
+    __ CallRuntime(Runtime::kNewStringWrapper, 1);
+  }
   __ ret(0);
 }
 
@@ -1589,7 +1603,7 @@
 
 void Builtins::Generate_OnStackReplacement(MacroAssembler* masm) {
   CpuFeatures::TryForceFeatureScope scope(SSE2);
-  if (!CpuFeatures::IsSupported(SSE2)) {
+  if (!CpuFeatures::IsSupported(SSE2) && FLAG_debug_code) {
     __ Abort("Unreachable code: Cannot optimize without SSE2 support.");
     return;
   }
@@ -1616,10 +1630,11 @@
 
   // Pass the function to optimize as the argument to the on-stack
   // replacement runtime function.
-  __ EnterInternalFrame();
-  __ push(eax);
-  __ CallRuntime(Runtime::kCompileForOnStackReplacement, 1);
-  __ LeaveInternalFrame();
+  {
+    FrameScope scope(masm, StackFrame::INTERNAL);
+    __ push(eax);
+    __ CallRuntime(Runtime::kCompileForOnStackReplacement, 1);
+  }
 
   // If the result was -1 it means that we couldn't optimize the
   // function. Just return and continue in the unoptimized version.
@@ -1638,7 +1653,9 @@
   __ j(above_equal, &ok, Label::kNear);
   StackCheckStub stub;
   __ TailCallStub(&stub);
-  __ Abort("Unreachable code: returned from tail call.");
+  if (FLAG_debug_code) {
+    __ Abort("Unreachable code: returned from tail call.");
+  }
   __ bind(&ok);
   __ ret(0);