[fullcode] Switch passing of new.target to register.

src/full-codegen/arm64/full-codegen-arm64.cc

 // Copyright 2013 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.
 
 #if V8_TARGET_ARCH_ARM64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 74 matching lines @@
 };
 
 
 // Generate code for a JS function. On entry to the function the receiver
 // and arguments have been pushed on the stack left to right. The actual
 // argument count matches the formal parameter count expected by the
 // function.
 //
 // The live registers are:
 //   - x1: the JS function object being called (i.e. ourselves).
+//   - x3: the new target value
 //   - cp: our context.
 //   - fp: our caller's frame pointer.
 //   - jssp: stack pointer.
 //   - lr: return address.
 //
 // The function builds a JS frame. See JavaScriptFrameConstants in
 // frames-arm.h for its layout.
 void FullCodeGenerator::Generate() {
   CompilationInfo* info = info_;
   profiling_counter_ = isolate()->factory()->NewCell(
@@ skipping 46 matching lines @@
         __ CallRuntime(Runtime::kThrowStackOverflow, 0);
         __ Bind(&ok);
       }
       __ LoadRoot(x10, Heap::kUndefinedValueRootIndex);
       if (FLAG_optimize_for_size) {
         __ PushMultipleTimes(x10 , locals_count);
       } else {
         const int kMaxPushes = 32;
         if (locals_count >= kMaxPushes) {
           int loop_iterations = locals_count / kMaxPushes;
-          __ Mov(x3, loop_iterations);
+          __ Mov(x2, loop_iterations);
           Label loop_header;
           __ Bind(&loop_header);
           // Do pushes.
           __ PushMultipleTimes(x10 , kMaxPushes);
-          __ Subs(x3, x3, 1);
+          __ Subs(x2, x2, 1);
           __ B(ne, &loop_header);
         }
         int remaining = locals_count % kMaxPushes;
         // Emit the remaining pushes.
         __ PushMultipleTimes(x10 , remaining);
       }
     }
   }
 
   bool function_in_register_x1 = true;
 
   if (info->scope()->num_heap_slots() > 0) {
     // Argument to NewContext is the function, which is still in x1.
     Comment cmnt(masm_, "[ Allocate context");
     bool need_write_barrier = true;
     int slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     if (info->scope()->is_script_scope()) {
       __ Mov(x10, Operand(info->scope()->GetScopeInfo(info->isolate())));
       __ Push(x1, x10);
       __ CallRuntime(Runtime::kNewScriptContext, 2);
       PrepareForBailoutForId(BailoutId::ScriptContext(), TOS_REG);
-    } else if (slots <= FastNewContextStub::kMaximumSlots) {
-      FastNewContextStub stub(isolate(), slots);
-      __ CallStub(&stub);
-      // Result of FastNewContextStub is always in new space.
-      need_write_barrier = false;
+      // The new target value is not used, clobbering is safe.
+      DCHECK_NULL(info->scope()->new_target_var());
     } else {
-      __ Push(x1);
-      __ CallRuntime(Runtime::kNewFunctionContext, 1);
+      if (info->scope()->new_target_var() != nullptr) {
+        __ Push(x3);  // Preserve new target.
+      }
+      if (slots <= FastNewContextStub::kMaximumSlots) {
+        FastNewContextStub stub(isolate(), slots);
+        __ CallStub(&stub);
+        // Result of FastNewContextStub is always in new space.
+        need_write_barrier = false;
+      } else {
+        __ Push(x1);
+        __ CallRuntime(Runtime::kNewFunctionContext, 1);
+      }
+      if (info->scope()->new_target_var() != nullptr) {
+        __ Pop(x3);  // Restore new target.
+      }
     }
     function_in_register_x1 = false;
     // Context is returned in x0.  It replaces the context passed to us.
     // It's saved in the stack and kept live in cp.
     __ Mov(cp, x0);
     __ Str(x0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = info->scope()->num_parameters();
     int first_parameter = info->scope()->has_this_declaration() ? -1 : 0;
     for (int i = first_parameter; i < num_parameters; i++) {
@@ skipping 13 matching lines @@
                                     x11, kLRHasBeenSaved, kDontSaveFPRegs);
         } else if (FLAG_debug_code) {
           Label done;
           __ JumpIfInNewSpace(cp, &done);
           __ Abort(kExpectedNewSpaceObject);
           __ bind(&done);
         }
       }
     }
   }
+
+  // Register holding this function and new target are both trashed in case we
+  // bailout here. But since that can happen only when new target is not used
+  // and we allocate a context, the value of |function_in_register| is correct.
   PrepareForBailoutForId(BailoutId::FunctionContext(), NO_REGISTERS);
 
-  // Function register is trashed in case we bailout here. But since that
-  // could happen only when we allocate a context the value of
-  // |function_in_register_x1| is correct.
-
   // Possibly set up a local binding to the this function which is used in
   // derived constructors with super calls.
   Variable* this_function_var = scope()->this_function_var();
   if (this_function_var != nullptr) {
     Comment cmnt(masm_, "[ This function");
     if (!function_in_register_x1) {
       __ Ldr(x1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
       // The write barrier clobbers register again, keep it marked as such.
     }
     SetVar(this_function_var, x1, x0, x2);
   }
 
+  // Possibly set up a local binding to the new target value.
   Variable* new_target_var = scope()->new_target_var();
   if (new_target_var != nullptr) {
     Comment cmnt(masm_, "[ new.target");
-    // Get the frame pointer for the calling frame.
-    __ Ldr(x2, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
-
-    Label check_frame_marker;
-    __ Ldr(x1, MemOperand(x2, StandardFrameConstants::kContextOffset));
-    __ Cmp(x1, Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-    __ B(ne, &check_frame_marker);
-    __ Ldr(x2, MemOperand(x2, StandardFrameConstants::kCallerFPOffset));
-    __ Bind(&check_frame_marker);
-    __ Ldr(x1, MemOperand(x2, StandardFrameConstants::kMarkerOffset));
-    __ Cmp(x1, Smi::FromInt(StackFrame::CONSTRUCT));
-    function_in_register_x1 = false;
-
-    Label non_construct_frame, done;
-
-    __ B(ne, &non_construct_frame);
-    __ Ldr(x0, MemOperand(x2, ConstructFrameConstants::kNewTargetOffset));
-    __ B(&done);
-
-    __ Bind(&non_construct_frame);
-    __ LoadRoot(x0, Heap::kUndefinedValueRootIndex);
-
-    __ Bind(&done);
-
-    SetVar(new_target_var, x0, x2, x3);
+    SetVar(new_target_var, x3, x0, x2);
   }
 
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Function uses arguments object.
     Comment cmnt(masm_, "[ Allocate arguments object");
     DCHECK(x1.is(ArgumentsAccessNewDescriptor::function()));
     if (!function_in_register_x1) {
       // Load this again, if it's used by the local context below.
       __ Ldr(x1, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
@@ skipping 4666 matching lines @@
   }
 
   return INTERRUPT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64