Allow functions to have custom construct stubs that are called

when the function is instantiated.
Review URL: http://codereview.chromium.org/132063

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2222 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/builtins-arm.cc

@@ -67,6 +67,24 @@ void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   __ CompareObjectType(r1, r2, r2, JS_FUNCTION_TYPE);
   __ b(ne, &non_function_call);
 
+  // Jump to the function-specific construct stub.
+  __ ldr(r2, FieldMemOperand(r1, JSFunction::kSharedFunctionInfoOffset));
+  __ ldr(r2, FieldMemOperand(r2, SharedFunctionInfo::kConstructStubOffset));
+  __ add(pc, r2, Operand(Code::kHeaderSize - kHeapObjectTag));
+
+  // r0: number of arguments
+  // r1: called object
+  __ bind(&non_function_call);
+
+  // Set expected number of arguments to zero (not changing r0).
+  __ mov(r2, Operand(0));
+  __ GetBuiltinEntry(r3, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
+  __ Jump(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
+          RelocInfo::CODE_TARGET);
+}
+
+
+void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
   // Enter a construct frame.
   __ EnterConstructFrame();
 
@@ -177,16 +195,6 @@ void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   __ add(sp, sp, Operand(r1, LSL, kPointerSizeLog2 - 1));
   __ add(sp, sp, Operand(kPointerSize));
   __ Jump(lr);
-
-  // r0: number of arguments
-  // r1: called object
-  __ bind(&non_function_call);
-
-  // Set expected number of arguments to zero (not changing r0).
-  __ mov(r2, Operand(0));
-  __ GetBuiltinEntry(r3, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
-  __ Jump(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
-          RelocInfo::CODE_TARGET);
 }
 
 

src/builtins.h

@@ -51,6 +51,7 @@ namespace internal {
 #define BUILTIN_LIST_A(V)                                      \
   V(ArgumentsAdaptorTrampoline, BUILTIN, UNINITIALIZED)        \
   V(JSConstructCall,            BUILTIN, UNINITIALIZED)        \
+  V(JSConstructStubGeneric,     BUILTIN, UNINITIALIZED)        \
   V(JSEntryTrampoline,          BUILTIN, UNINITIALIZED)        \
   V(JSConstructEntryTrampoline, BUILTIN, UNINITIALIZED)        \
                                                                \
@@ -210,6 +211,7 @@ class Builtins : public AllStatic {
 
   static void Generate_Adaptor(MacroAssembler* masm, CFunctionId id);
   static void Generate_JSConstructCall(MacroAssembler* masm);
+  static void Generate_JSConstructStubGeneric(MacroAssembler* masm);
   static void Generate_JSEntryTrampoline(MacroAssembler* masm);
   static void Generate_JSConstructEntryTrampoline(MacroAssembler* masm);
   static void Generate_ArgumentsAdaptorTrampoline(MacroAssembler* masm);

src/heap.cc

@@ -1510,6 +1510,8 @@ Object* Heap::AllocateSharedFunctionInfo(Object* name) {
   share->set_name(name);
   Code* illegal = Builtins::builtin(Builtins::Illegal);
   share->set_code(illegal);
+  Code* construct_stub = Builtins::builtin(Builtins::JSConstructStubGeneric);
+  share->set_construct_stub(construct_stub);
   share->set_expected_nof_properties(0);
   share->set_length(0);
   share->set_formal_parameter_count(0);

src/ia32/builtins-ia32.cc

@@ -63,6 +63,25 @@ void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   __ CmpObjectType(edi, JS_FUNCTION_TYPE, ecx);
   __ j(not_equal, &non_function_call);
 
+  // Jump to the function-specific construct stub.
+  __ mov(ebx, FieldOperand(edi, JSFunction::kSharedFunctionInfoOffset));
+  __ mov(ebx, FieldOperand(ebx, SharedFunctionInfo::kConstructStubOffset));
+  __ lea(ebx, FieldOperand(ebx, Code::kHeaderSize));
+  __ jmp(Operand(ebx));
+
+  // edi: called object
+  // eax: number of arguments
+  __ bind(&non_function_call);
+
+  // Set expected number of arguments to zero (not changing eax).
+  __ Set(ebx, Immediate(0));
+  __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
+  __ jmp(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
+         RelocInfo::CODE_TARGET);
+}
+
+
+void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
   // Enter a construct frame.
   __ EnterConstructFrame();
 
@@ -305,16 +324,6 @@ void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   __ lea(esp, Operand(esp, ebx, times_2, 1 * kPointerSize));  // 1 ~ receiver
   __ push(ecx);
   __ ret(0);
-
-  // edi: called object
-  // eax: number of arguments
-  __ bind(&non_function_call);
-
-  // Set expected number of arguments to zero (not changing eax).
-  __ Set(ebx, Immediate(0));
-  __ GetBuiltinEntry(edx, Builtins::CALL_NON_FUNCTION_AS_CONSTRUCTOR);
-  __ jmp(Handle<Code>(builtin(ArgumentsAdaptorTrampoline)),
-         RelocInfo::CODE_TARGET);
 }
 
 

src/objects-inl.h

@@ -2130,6 +2130,7 @@ ACCESSORS(BreakPointInfo, statement_position, Smi, kStatementPositionIndex)
 ACCESSORS(BreakPointInfo, break_point_objects, Object, kBreakPointObjectsIndex)
 #endif
 
+ACCESSORS(SharedFunctionInfo, construct_stub, Code, kConstructStubOffset)
 ACCESSORS(SharedFunctionInfo, name, Object, kNameOffset)
 ACCESSORS(SharedFunctionInfo, instance_class_name, Object,
           kInstanceClassNameOffset)

src/objects.cc

@@ -4632,7 +4632,7 @@ void SharedFunctionInfo::SourceCodePrint(StringStream* accumulator,
 
 
 void SharedFunctionInfo::SharedFunctionInfoIterateBody(ObjectVisitor* v) {
-  IteratePointers(v, kNameOffset, kCodeOffset + kPointerSize);
+  IteratePointers(v, kNameOffset, kConstructStubOffset + kPointerSize);
   IteratePointers(v, kInstanceClassNameOffset, kScriptOffset + kPointerSize);
   IteratePointers(v, kDebugInfoOffset, kInferredNameOffset + kPointerSize);
 }

src/objects.h

@@ -2743,6 +2743,9 @@ class SharedFunctionInfo: public HeapObject {
   // [code]: Function code.
   DECL_ACCESSORS(code, Code)
 
+  // [construct stub]: Code stub for constructing instances of this function.
+  DECL_ACCESSORS(construct_stub, Code)
+
   // Returns if this function has been compiled to native code yet.
   inline bool is_compiled();
 
@@ -2838,7 +2841,8 @@ class SharedFunctionInfo: public HeapObject {
   // (An even number of integers has a size that is a multiple of a pointer.)
   static const int kNameOffset = HeapObject::kHeaderSize;
   static const int kCodeOffset = kNameOffset + kPointerSize;
-  static const int kLengthOffset = kCodeOffset + kPointerSize;
+  static const int kConstructStubOffset = kCodeOffset + kPointerSize;
+  static const int kLengthOffset = kConstructStubOffset + kPointerSize;
   static const int kFormalParameterCountOffset = kLengthOffset + kIntSize;
   static const int kExpectedNofPropertiesOffset =
       kFormalParameterCountOffset + kIntSize;

src/runtime.cc

@@ -4328,45 +4328,61 @@ static Object* Runtime_NewClosure(Arguments args) {
 }
 
 
+static Handle<Code> ComputeConstructStub(Handle<Map> map) {
+  // TODO(385): Change this to create a construct stub specialized for
+  // the given map to make allocation of simple objects - and maybe
+  // arrays - much faster.
+  return Handle<Code>(Builtins::builtin(Builtins::JSConstructStubGeneric));
+}
+
+
 static Object* Runtime_NewObject(Arguments args) {
-  NoHandleAllocation ha;
+  HandleScope scope;
   ASSERT(args.length() == 1);
 
-  Object* constructor = args[0];
-  if (constructor->IsJSFunction()) {
-    JSFunction* function = JSFunction::cast(constructor);
+  Handle<Object> constructor = args.at<Object>(0);
+
+  // If the constructor isn't a proper function we throw a type error.
+  if (!constructor->IsJSFunction()) {
+    Vector< Handle<Object> > arguments = HandleVector(&constructor, 1);
+    Handle<Object> type_error =
+        Factory::NewTypeError("not_constructor", arguments);
+    return Top::Throw(*type_error);
+  }
 
-    // Handle stepping into constructors if step into is active.
+  Handle<JSFunction> function = Handle<JSFunction>::cast(constructor);
 #ifdef ENABLE_DEBUGGER_SUPPORT
-    if (Debug::StepInActive()) {
-      HandleScope scope;
-      Debug::HandleStepIn(Handle<JSFunction>(function), 0, true);
-    }
+  // Handle stepping into constructors if step into is active.
+  if (Debug::StepInActive()) {
+    Debug::HandleStepIn(function, 0, true);
+  }
 #endif
 
-    if (function->has_initial_map() &&
-        function->initial_map()->instance_type() == JS_FUNCTION_TYPE) {
+  if (function->has_initial_map()) {
+    if (function->initial_map()->instance_type() == JS_FUNCTION_TYPE) {
       // The 'Function' function ignores the receiver object when
       // called using 'new' and creates a new JSFunction object that
       // is returned.  The receiver object is only used for error
       // reporting if an error occurs when constructing the new
-      // JSFunction.  AllocateJSObject should not be used to allocate
-      // JSFunctions since it does not properly initialize the shared
-      // part of the function.  Since the receiver is ignored anyway,
-      // we use the global object as the receiver instead of a new
-      // JSFunction object.  This way, errors are reported the same
-      // way whether or not 'Function' is called using 'new'.
+      // JSFunction. Factory::NewJSObject() should not be used to
+      // allocate JSFunctions since it does not properly initialize
+      // the shared part of the function. Since the receiver is
+      // ignored anyway, we use the global object as the receiver
+      // instead of a new JSFunction object. This way, errors are
+      // reported the same way whether or not 'Function' is called
+      // using 'new'.
       return Top::context()->global();
     }
-    return Heap::AllocateJSObject(function);
   }
 
-  HandleScope scope;
-  Handle<Object> cons(constructor);
-  // The constructor is not a function; throw a type error.
-  Handle<Object> type_error =
-    Factory::NewTypeError("not_constructor", HandleVector(&cons, 1));
-  return Top::Throw(*type_error);
+  bool first_allocation = !function->has_initial_map();
+  Handle<JSObject> result = Factory::NewJSObject(function);
+  if (first_allocation) {
+    Handle<Map> map = Handle<Map>(function->initial_map());
+    Handle<Code> stub = ComputeConstructStub(map);
+    function->shared()->set_construct_stub(*stub);
+  }
+  return *result;
 }
 
 

src/x64/builtins-x64.cc

@@ -171,6 +171,10 @@ void Builtins::Generate_JSConstructCall(MacroAssembler* masm) {
   masm->int3();  // UNIMPLEMENTED.
 }
 
+void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
+  masm->int3();  // UNIMPLEMENTED.
+}
+
 static void Generate_JSEntryTrampolineHelper(MacroAssembler* masm,
                                              bool is_construct) {
   // Expects five C++ function parameters.