[es6] Make new.target work in functions

src/mips/builtins-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_MIPS
 
@@ skipping 330 matching lines @@
   if (create_memento) {
     __ jmp(count_incremented);
   } else {
     __ jmp(allocated);
   }
 }
 
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
+                                           bool use_new_target,
                                            bool create_memento) {
   // ----------- S t a t e -------------
   //  -- a0     : number of arguments
   //  -- a1     : constructor function
   //  -- a2     : allocation site or undefined
   //  -- a3     : original constructor
   //  -- ra     : return address
   //  -- sp[...]: constructor arguments
   // -----------------------------------
 
@@ skipping 12 matching lines @@
   // Enter a construct frame.
   {
     FrameScope scope(masm, StackFrame::CONSTRUCT);
 
     if (create_memento) {
       __ AssertUndefinedOrAllocationSite(a2, t0);
       __ push(a2);
     }
 
     // Preserve the two incoming parameters on the stack.
-    __ sll(a0, a0, kSmiTagSize);  // Tag arguments count.
-    __ MultiPushReversed(a0.bit() | a1.bit());
+    __ SmiTag(a0);  // Tag arguments count.
+    if (use_new_target) {
+      __ MultiPushReversed(a0.bit() | a1.bit() | a3.bit());

[paul.l..., 2015/06/26 04:02:24]

nit: this would be more readable as Push(a0, a1, a3); and similar just below. No
functional change, and not related to your CL.

+    } else {
+      __ MultiPushReversed(a0.bit() | a1.bit());
+    }
 
     Label rt_call, allocated, normal_new, count_incremented;
     __ Branch(&normal_new, eq, a1, Operand(a3));
 
     // Original constructor and function are different.
     Generate_Runtime_NewObject(masm, create_memento, a3, &count_incremented,
                                &allocated);
     __ bind(&normal_new);
 
     // Try to allocate the object without transitioning into C code. If any of
@@ skipping 226 matching lines @@
     // a1: constructor function
     __ bind(&rt_call);
     Generate_Runtime_NewObject(masm, create_memento, a1, &count_incremented,
                                &allocated);
 
     // Receiver for constructor call allocated.
     // t4: JSObject
     __ bind(&allocated);
 
     if (create_memento) {
-      __ lw(a2, MemOperand(sp, kPointerSize * 2));
+      int offset = (use_new_target ? 3 : 2) * kPointerSize;
+      __ lw(a2, MemOperand(sp, offset));
       __ LoadRoot(t5, Heap::kUndefinedValueRootIndex);
       __ Branch(&count_incremented, eq, a2, Operand(t5));
       // a2 is an AllocationSite. We are creating a memento from it, so we
       // need to increment the memento create count.
       __ lw(a3, FieldMemOperand(a2,
                                 AllocationSite::kPretenureCreateCountOffset));
       __ Addu(a3, a3, Operand(Smi::FromInt(1)));
       __ sw(a3, FieldMemOperand(a2,
                                 AllocationSite::kPretenureCreateCountOffset));
       __ bind(&count_incremented);
     }
 
+    // Restore the parameters.
+    if (use_new_target) {
+      __ Pop(a3);  // new.target
+    }
     __ Pop(a1);
 
-    __ Push(t4, t4);
+    // Retrieve smi-tagged arguments count from the stack.
+    __ lw(a0, MemOperand(sp));
+    __ SmiUntag(a0);
 
-    // Reload the number of arguments from the stack.
-    // sp[0]: receiver
-    // sp[1]: receiver
-    // sp[2]: number of arguments (smi-tagged)
-    __ lw(a3, MemOperand(sp, 2 * kPointerSize));
+    if (use_new_target) {
+      __ Push(a3, t4, t4);
+    } else {
+      __ Push(t4, t4);
+    }
 
     // Set up pointer to last argument.
     __ Addu(a2, fp, Operand(StandardFrameConstants::kCallerSPOffset));
 

[paul.l..., 2015/06/26 04:02:24]

Set up a3 as Smi-tagged loop counter.
  __ SmiTag(a3, a0);

-    // Set up number of arguments for function call below.
-    __ srl(a0, a3, kSmiTagSize);
-
     // Copy arguments and receiver to the expression stack.
     // a0: number of arguments
     // a1: constructor function
     // a2: address of last argument (caller sp)
     // a3: number of arguments (smi-tagged)
     // sp[0]: receiver
     // sp[1]: receiver
-    // sp[2]: number of arguments (smi-tagged)
+    // sp[2]: new.target (if used)
+    // sp[2/3]: number of arguments (smi-tagged)
     Label loop, entry;
     __ jmp(&entry);
     __ bind(&loop);
     __ sll(t0, a3, kPointerSizeLog2 - kSmiTagSize);
     __ Addu(t0, a2, Operand(t0));
     __ lw(t1, MemOperand(t0));
     __ push(t1);
     __ bind(&entry);
     __ Addu(a3, a3, Operand(-2));
     __ Branch(&loop, greater_equal, a3, Operand(zero_reg));
 
     // Call the function.
     // a0: number of arguments
     // a1: constructor function
     if (is_api_function) {
       __ lw(cp, FieldMemOperand(a1, JSFunction::kContextOffset));
       Handle<Code> code =
           masm->isolate()->builtins()->HandleApiCallConstruct();
       __ Call(code, RelocInfo::CODE_TARGET);
     } else {
       ParameterCount actual(a0);
       __ InvokeFunction(a1, actual, CALL_FUNCTION, NullCallWrapper());
     }
 
     // Store offset of return address for deoptimizer.
-    if (!is_api_function) {
+    // TODO(arv): Remove the "!use_new_target" before supporting optimization
+    // of functions that reference new.target
+    if (!is_api_function && !use_new_target) {
       masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
     }
 
     // Restore context from the frame.
     __ lw(cp, MemOperand(fp, 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 a smi, it is *not* an object in the ECMA sense.
     // v0: result
     // sp[0]: receiver (newly allocated object)
-    // sp[1]: number of arguments (smi-tagged)
+    // sp[1]: new.target (if used)
+    // sp[1/2]: number of arguments (smi-tagged)
     __ JumpIfSmi(v0, &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.
     __ GetObjectType(v0, a1, a3);
     __ Branch(&exit, greater_equal, a3, Operand(FIRST_SPEC_OBJECT_TYPE));
 
     // Throw away the result of the constructor invocation and use the
     // on-stack receiver as the result.
     __ bind(&use_receiver);
     __ lw(v0, MemOperand(sp));
 
     // Remove receiver from the stack, remove caller arguments, and
     // return.
     __ bind(&exit);
     // v0: result
     // sp[0]: receiver (newly allocated object)
-    // sp[1]: number of arguments (smi-tagged)
-    __ lw(a1, MemOperand(sp, kPointerSize));
+    // sp[1]: new.target (if used)
+    // sp[1/2]: number of arguments (smi-tagged)
+    int offset = (use_new_target ? 2 : 1) * kPointerSize;
+    __ lw(a1, MemOperand(sp, offset));
 
     // Leave construct frame.
   }
 
   __ sll(t0, a1, kPointerSizeLog2 - 1);
   __ Addu(sp, sp, t0);
   __ Addu(sp, sp, kPointerSize);
   __ IncrementCounter(isolate->counters()->constructed_objects(), 1, a1, a2);
   __ Ret();
 }
 
 
 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, FLAG_pretenuring_call_new);
+  Generate_JSConstructStubHelper(masm, false, false, FLAG_pretenuring_call_new);
 }
 
 
 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, true, false);
+  Generate_JSConstructStubHelper(masm, true, false, false);
 }
 
 
+void Builtins::Generate_JSConstructStubNewTarget(MacroAssembler* masm) {
+  Generate_JSConstructStubHelper(masm, false, true, FLAG_pretenuring_call_new);
+}
+
+
 void Builtins::Generate_JSConstructStubForDerived(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a0     : number of arguments
   //  -- a1     : constructor function
   //  -- a2     : allocation site or undefined
   //  -- a3     : original constructor
   //  -- ra     : return address
   //  -- sp[...]: constructor arguments
   // -----------------------------------
 
@@ skipping 1074 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS