Do not add extra argument for new.target

src/arm/full-codegen-arm.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_ARM
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 231 matching lines @@
   // derived constructors with super calls.
   Variable* this_function_var = scope()->this_function_var();
   if (this_function_var != nullptr) {
     Comment cmnt(masm_, "[ This function");
     SetVar(this_function_var, r1, r0, r2);
   }
 
   Variable* new_target_var = scope()->new_target_var();
   if (new_target_var != nullptr) {
     Comment cmnt(masm_, "[ new.target");
-    // new.target is parameter -2.
-    int offset = 2 * kPointerSize +
-                 (info_->scope()->num_parameters() + 1) * kPointerSize;
-    __ ldr(r0, MemOperand(fp, offset));
+
+    __ ldr(r2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+    __ ldr(r1, MemOperand(r2, StandardFrameConstants::kContextOffset));
+    __ cmp(r1, Operand(Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR)));

[arv (Not doing code reviews), 2015/06/26 00:47:41]

You missed a branch here.

[arv (Not doing code reviews), 2015/06/26 15:15:33]

Never mind... I see the trailing eq now... Something else is going wrong in my
case.

+    __ ldr(r2, MemOperand(r2, StandardFrameConstants::kCallerFPOffset), eq);
+    __ ldr(r1, MemOperand(r2, StandardFrameConstants::kMarkerOffset));
+    __ cmp(r1, Operand(Smi::FromInt(StackFrame::CONSTRUCT)));
+    Label non_construct_frame, done;
+
+    __ b(ne, &non_construct_frame);
+    __ ldr(r0, MemOperand(r2, StandardFrameConstants::kExpressionsOffset -
+                                  2 * kPointerSize));
+    __ b(&done);
+
+    __ bind(&non_construct_frame);
+    __ LoadRoot(r0, Heap::kUndefinedValueRootIndex);
+    __ bind(&done);
+
     SetVar(new_target_var, r0, r2, r3);
   }
 
-  ArgumentsAccessStub::HasNewTarget has_new_target =
-      IsSubclassConstructor(info->function()->kind())
-          ? ArgumentsAccessStub::HAS_NEW_TARGET
-          : ArgumentsAccessStub::NO_NEW_TARGET;
-
   // Possibly allocate RestParameters
   int rest_index;
   Variable* rest_param = scope()->rest_parameter(&rest_index);
   if (rest_param) {
     Comment cmnt(masm_, "[ Allocate rest parameter array");
 
     int num_parameters = info->scope()->num_parameters();
     int offset = num_parameters * kPointerSize;
-    if (has_new_target == ArgumentsAccessStub::HAS_NEW_TARGET) {
-      --num_parameters;
-      ++rest_index;
-    }
 
     __ add(r3, fp, Operand(StandardFrameConstants::kCallerSPOffset + offset));
     __ mov(r2, Operand(Smi::FromInt(num_parameters)));
     __ mov(r1, Operand(Smi::FromInt(rest_index)));
     __ mov(r0, Operand(Smi::FromInt(language_mode())));
     __ Push(r3, r2, r1, r0);
 
     RestParamAccessStub stub(isolate());
     __ CallStub(&stub);
 
     SetVar(rest_param, r0, r1, r2);
   }
 
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Function uses arguments object.
     Comment cmnt(masm_, "[ Allocate arguments object");
     if (!function_in_register) {
       // Load this again, if it's used by the local context below.
       __ ldr(r3, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
     } else {
       __ mov(r3, r1);
     }
     // Receiver is just before the parameters on the caller's stack.
     int num_parameters = info->scope()->num_parameters();
     int offset = num_parameters * kPointerSize;
-    __ add(r2, fp,
-           Operand(StandardFrameConstants::kCallerSPOffset + offset));
+
+    __ add(r2, fp, Operand(StandardFrameConstants::kCallerSPOffset + offset));
     __ mov(r1, Operand(Smi::FromInt(num_parameters)));
     __ Push(r3, r2, r1);
 
     // Arguments to ArgumentsAccessStub:
     //   function, receiver address, parameter count.
     // The stub will rewrite receiever and parameter count if the previous
     // stack frame was an arguments adapter frame.
     ArgumentsAccessStub::Type type;
     if (is_strict(language_mode()) || !is_simple_parameter_list()) {
       type = ArgumentsAccessStub::NEW_STRICT;
     } else if (function()->has_duplicate_parameters()) {
       type = ArgumentsAccessStub::NEW_SLOPPY_SLOW;
     } else {
       type = ArgumentsAccessStub::NEW_SLOPPY_FAST;
     }
-    ArgumentsAccessStub stub(isolate(), type, has_new_target);
+    ArgumentsAccessStub stub(isolate(), type);
     __ CallStub(&stub);
 
     SetVar(arguments, r0, r1, r2);
   }
 
 
   if (FLAG_trace) {
     __ CallRuntime(Runtime::kTraceEnter, 0);
   }
 
@@ skipping 161 matching lines @@
 
 #ifdef DEBUG
     // Add a label for checking the size of the code used for returning.
     Label check_exit_codesize;
     __ bind(&check_exit_codesize);
 #endif
     // Make sure that the constant pool is not emitted inside of the return
     // sequence.
     { Assembler::BlockConstPoolScope block_const_pool(masm_);
       int32_t arg_count = info_->scope()->num_parameters() + 1;
-      if (IsSubclassConstructor(info_->function()->kind())) {
-        arg_count++;
-      }
       int32_t sp_delta = arg_count * kPointerSize;
       CodeGenerator::RecordPositions(masm_, function()->end_position() - 1);
       // TODO(svenpanne) The code below is sometimes 4 words, sometimes 5!
       PredictableCodeSizeScope predictable(masm_, -1);
       __ RecordJSReturn();
       int no_frame_start = __ LeaveFrame(StackFrame::JAVA_SCRIPT);
       { ConstantPoolUnavailableScope constant_pool_unavailable(masm_);
         __ add(sp, sp, Operand(sp_delta));
         __ Jump(lr);
         info_->AddNoFrameRange(no_frame_start, masm_->pc_offset());
@@ skipping 3760 matching lines @@
   __ b(eq, &adaptor_frame);
   // default constructor has no arguments, so no adaptor frame means no args.
   __ mov(r0, Operand::Zero());
   __ b(&args_set_up);
 
   // Copy arguments from adaptor frame.
   {
     __ bind(&adaptor_frame);
     __ ldr(r1, MemOperand(r2, ArgumentsAdaptorFrameConstants::kLengthOffset));
     __ SmiUntag(r1, r1);
-
-    // Subtract 1 from arguments count, for new.target.
-    __ sub(r1, r1, Operand(1));
     __ mov(r0, r1);
 
     // Get arguments pointer in r2.
     __ add(r2, r2, Operand(r1, LSL, kPointerSizeLog2));
     __ add(r2, r2, Operand(StandardFrameConstants::kCallerSPOffset));
     Label loop;
     __ bind(&loop);
     // Pre-decrement r2 with kPointerSize on each iteration.
     // Pre-decrement in order to skip receiver.
     __ ldr(r3, MemOperand(r2, kPointerSize, NegPreIndex));
@@ skipping 1312 matching lines @@
   DCHECK(interrupt_address ==
          isolate->builtins()->OsrAfterStackCheck()->entry());
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM