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

src/full-codegen/x64/full-codegen-x64.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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 64 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, with the
 // return address on top of them.  The actual argument count matches the
 // formal parameter count expected by the function.
 //
 // The live registers are:
 //   o rdi: the JS function object being called (i.e. ourselves)
+//   o rdx: the new target value
 //   o rsi: our context
 //   o rbp: our caller's frame pointer
 //   o rsp: stack pointer (pointing to return address)
 //
 // The function builds a JS frame.  Please see JavaScriptFrameConstants in
 // frames-x64.h for its layout.
 void FullCodeGenerator::Generate() {
   CompilationInfo* info = info_;
   profiling_counter_ = isolate()->factory()->NewCell(
       Handle<Smi>(Smi::FromInt(FLAG_interrupt_budget), isolate()));
@@ skipping 34 matching lines @@
     } else if (locals_count > 1) {
       if (locals_count >= 128) {
         Label ok;
         __ movp(rcx, rsp);
         __ subp(rcx, Immediate(locals_count * kPointerSize));
         __ CompareRoot(rcx, Heap::kRealStackLimitRootIndex);
         __ j(above_equal, &ok, Label::kNear);
         __ CallRuntime(Runtime::kThrowStackOverflow, 0);
         __ bind(&ok);
       }
-      __ LoadRoot(rdx, Heap::kUndefinedValueRootIndex);
+      __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
       const int kMaxPushes = 32;
       if (locals_count >= kMaxPushes) {
         int loop_iterations = locals_count / kMaxPushes;
         __ movp(rcx, Immediate(loop_iterations));
         Label loop_header;
         __ bind(&loop_header);
         // Do pushes.
         for (int i = 0; i < kMaxPushes; i++) {
-          __ Push(rdx);
+          __ Push(rax);
         }
         // Continue loop if not done.
         __ decp(rcx);
         __ j(not_zero, &loop_header, Label::kNear);
       }
       int remaining = locals_count % kMaxPushes;
       // Emit the remaining pushes.
       for (int i  = 0; i < remaining; i++) {
-        __ Push(rdx);
+        __ Push(rax);
       }
     }
   }
 
   bool function_in_register = true;
 
   // Possibly allocate a local context.
   if (info->scope()->num_heap_slots() > 0) {
     Comment cmnt(masm_, "[ Allocate context");
     bool need_write_barrier = true;
     int slots = info->scope()->num_heap_slots() - Context::MIN_CONTEXT_SLOTS;
     // Argument to NewContext is the function, which is still in rdi.
     if (info->scope()->is_script_scope()) {
       __ Push(rdi);
       __ Push(info->scope()->GetScopeInfo(info->isolate()));
       __ 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(rdi);
-      __ CallRuntime(Runtime::kNewFunctionContext, 1);
+      if (info->scope()->new_target_var() != nullptr) {
+        __ Push(rdx);  // 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(rdi);
+        __ CallRuntime(Runtime::kNewFunctionContext, 1);
+      }
+      if (info->scope()->new_target_var() != nullptr) {
+        __ Pop(rdx);  // Restore new target.
+      }
     }
     function_in_register = false;
     // Context is returned in rax.  It replaces the context passed to us.
     // It's saved in the stack and kept live in rsi.
     __ movp(rsi, rax);
     __ movp(Operand(rbp, StandardFrameConstants::kContextOffset), rax);
 
     // Copy any necessary parameters into the context.
     int num_parameters = info->scope()->num_parameters();
     int first_parameter = info->scope()->has_this_declaration() ? -1 : 0;
@@ skipping 13 matching lines @@
               rsi, context_offset, rax, rbx, kDontSaveFPRegs);
         } else if (FLAG_debug_code) {
           Label done;
           __ JumpIfInNewSpace(rsi, rax, &done, Label::kNear);
           __ 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| 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) {
       __ movp(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
       // The write barrier clobbers register again, keep it marked as such.
     }
-    SetVar(this_function_var, rdi, rbx, rdx);
+    SetVar(this_function_var, rdi, rbx, rcx);
   }
 
+  // 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");
-
-    __ movp(rax, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
-    Label non_adaptor_frame;
-    __ Cmp(Operand(rax, StandardFrameConstants::kContextOffset),
-           Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
-    __ j(not_equal, &non_adaptor_frame);
-    __ movp(rax, Operand(rax, StandardFrameConstants::kCallerFPOffset));
-
-    __ bind(&non_adaptor_frame);
-    __ Cmp(Operand(rax, StandardFrameConstants::kMarkerOffset),
-           Smi::FromInt(StackFrame::CONSTRUCT));
-
-    Label non_construct_frame, done;
-    __ j(not_equal, &non_construct_frame);
-
-    // Construct frame
-    __ movp(rax, Operand(rax, ConstructFrameConstants::kNewTargetOffset));
-    __ jmp(&done);
-
-    // Non-construct frame
-    __ bind(&non_construct_frame);
-    __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
-
-    __ bind(&done);
-    SetVar(new_target_var, rax, rbx, rdx);
+    SetVar(new_target_var, rdx, rbx, rcx);
   }
 
   // Possibly allocate an arguments object.
   Variable* arguments = scope()->arguments();
   if (arguments != NULL) {
     // Arguments object must be allocated after the context object, in
     // case the "arguments" or ".arguments" variables are in the context.
     Comment cmnt(masm_, "[ Allocate arguments object");
     DCHECK(rdi.is(ArgumentsAccessNewDescriptor::function()));
     if (!function_in_register) {
@@ skipping 4576 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64