[stubs] Port LoadFunctionPrototypeStub to CSA

src/arm64/macro-assembler-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/base/bits.h"
 #include "src/base/division-by-constant.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 3382 matching lines @@
   Ldr(result, FieldMemOperand(map, Map::kConstructorOrBackPointerOffset));
   Bind(&loop);
   JumpIfSmi(result, &done);
   CompareObjectType(result, temp, temp2, MAP_TYPE);
   B(ne, &done);
   Ldr(result, FieldMemOperand(result, Map::kConstructorOrBackPointerOffset));
   B(&loop);
   Bind(&done);
 }
 
-
-void MacroAssembler::TryGetFunctionPrototype(Register function, Register result,
-                                             Register scratch, Label* miss) {
-  DCHECK(!AreAliased(function, result, scratch));
-
-  // Get the prototype or initial map from the function.
-  Ldr(result,
-      FieldMemOperand(function, JSFunction::kPrototypeOrInitialMapOffset));
-
-  // If the prototype or initial map is the hole, don't return it and simply
-  // miss the cache instead. This will allow us to allocate a prototype object
-  // on-demand in the runtime system.
-  JumpIfRoot(result, Heap::kTheHoleValueRootIndex, miss);
-
-  // If the function does not have an initial map, we're done.
-  Label done;
-  JumpIfNotObjectType(result, scratch, scratch, MAP_TYPE, &done);
-
-  // Get the prototype from the initial map.
-  Ldr(result, FieldMemOperand(result, Map::kPrototypeOffset));
-
-  // All done.
-  Bind(&done);
-}
-
-
 void MacroAssembler::PushRoot(Heap::RootListIndex index) {
   UseScratchRegisterScope temps(this);
   Register temp = temps.AcquireX();
   LoadRoot(temp, index);
   Push(temp);
 }
 
 
 void MacroAssembler::CompareRoot(const Register& obj,
                                  Heap::RootListIndex index) {
@@ skipping 1221 matching lines @@
 }
 
 
 #undef __
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM64