Request for comments on overall approach.

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/assembler_macros.h"
 #include "vm/code_generator.h"
@@ skipping 276 matching lines @@
   // Total number of args is the first Smi in args descriptor array (R10).
   __ movq(RAX, FieldAddress(R10, Array::data_offset()));
   __ movq(RAX, Address(RSP, RAX, TIMES_4, 0));  // Get receiver. RAX is a Smi.
   // TODO(srdjan): Remove the special casing below for null receiver, once
   // NullClass is implemented.
   __ cmpq(RAX, raw_null);
   // Use Object class if receiver is null.
   __ j(EQUAL, &null_receiver, Assembler::kNearJump);
   __ testq(RAX, Immediate(kSmiTagMask));
   __ j(ZERO, &smi_receiver, Assembler::kNearJump);
-  __ movq(RAX, FieldAddress(RAX, Object::class_offset()));
+  __ GetClassOf(RAX, RAX);
   __ jmp(&class_in_rax, Assembler::kNearJump);
   __ Bind(&smi_receiver);
   // For Smis we need to get the class from the isolate.
   // Load current Isolate pointer from Context structure into RAX.
   __ movq(RAX, FieldAddress(CTX, Context::isolate_offset()));
   __ movq(RAX, Address(RAX, Isolate::object_store_offset()));
   __ movq(RAX, Address(RAX, ObjectStore::smi_class_offset()));
   __ jmp(&class_in_rax, Assembler::kNearJump);
   __ Bind(&null_receiver);
   __ movq(RAX, FieldAddress(CTX, Context::isolate_offset()));
@@ skipping 350 matching lines @@
     // R10: Array length as Smi.
 
     // Store the type argument field.
     __ StoreIntoObject(RAX,
                        FieldAddress(RAX, Array::type_arguments_offset()),
                        RBX);
 
     // Set the length field.
     __ StoreIntoObject(RAX, FieldAddress(RAX, Array::length_offset()), R10);
 
-    // Store class value for array.
-    __ movq(RBX, FieldAddress(CTX, Context::isolate_offset()));
-    __ movq(RBX, Address(RBX, Isolate::object_store_offset()));
-    __ movq(RBX, Address(RBX, ObjectStore::array_class_offset()));
-    __ StoreIntoObject(RAX, FieldAddress(RAX, Array::class_offset()), RBX);
     // Calculate the size tag.
     // RAX: new object start as a tagged pointer.
     // R12: new object end address.
     // R10: Array length as Smi.
     {
       Label size_tag_overflow, done;
       __ leaq(RBX, Address(R10, TIMES_4, fixed_size));  // R10 is Smi.
       ASSERT(kSmiTagShift == 1);
       __ andq(RBX, Immediate(-kObjectAlignment));
       __ cmpq(RBX, Immediate(RawObject::SizeTag::kMaxSizeTag));
@@ skipping 65 matching lines @@
 
   // Verify that R13 is a closure by checking its class.
   Label not_closure;
   __ cmpq(R13, raw_null);
   // Not a closure, but null object.
   __ j(EQUAL, &not_closure, Assembler::kNearJump);
   __ testq(R13, Immediate(kSmiTagMask));
   __ j(ZERO, &not_closure, Assembler::kNearJump);  // Not a closure, but a smi.
   // Verify that the class of the object is a closure class by checking that
   // class.signature_function() is not null.
-  __ movq(RAX, FieldAddress(R13, Object::class_offset()));
+  __ GetClassOf(RAX, R13);
   __ movq(RAX, FieldAddress(RAX, Class::signature_function_offset()));
   __ cmpq(RAX, raw_null);
   // Actual class is not a closure class.
   __ j(EQUAL, &not_closure, Assembler::kNearJump);
 
   // RAX is just the signature function. Load the actual closure function.
   __ movq(RBX, FieldAddress(R13, Closure::function_offset()));
 
   // Load closure context in CTX; note that CTX has already been preserved.
   __ movq(CTX, FieldAddress(R13, Closure::context_offset()));
@@ skipping 214 matching lines @@
 
     // Successfully allocated the object, now update top to point to
     // next object start and initialize the object.
     // RAX: new object.
     // R13: next object start.
     // R10: number of context variables.
     __ movq(RDI, Immediate(heap->TopAddress()));
     __ movq(Address(RDI, 0), R13);
     __ addq(RAX, Immediate(kHeapObjectTag));
 
-    // Initialize the class field in the context object.
-    // RAX: new object.
-    // R10: number of context variables.
-    __ LoadObject(R13, context_class);  // Load up class field of context.
-    __ StoreIntoObject(RAX,
-                       FieldAddress(RAX, Context::class_offset()),
-                       R13);
     // Calculate the size tag.
     // RAX: new object.
     // R10: number of context variables.
     {
       Label size_tag_overflow, done;
       __ leaq(R13, Address(R10, TIMES_8, fixed_size));
       __ andq(R13, Immediate(-kObjectAlignment));
       __ cmpq(R13, Immediate(RawObject::SizeTag::kMaxSizeTag));
       __ j(ABOVE, &size_tag_overflow, Assembler::kNearJump);
       __ shlq(R13, Immediate(RawObject::kSizeTagBit - kObjectAlignmentLog2));
@@ skipping 139 matching lines @@
       // Initialize InstantiatedTypeArguments object at RCX.
       __ movq(Address(RCX,
           InstantiatedTypeArguments::uninstantiated_type_arguments_offset()),
               RDI);
       __ movq(RDX, Address(RSP, kInstantiatorTypeArgumentsOffset));
       __ movq(Address(RCX,
           InstantiatedTypeArguments::instantiator_type_arguments_offset()),
               RDX);
       const Class& ita_cls =
           Class::ZoneHandle(Object::instantiated_type_arguments_class());
-      __ LoadObject(RDX, ita_cls);
-      __ movq(Address(RCX, Instance::class_offset()), RDX);  // Set its class.
       // Set the tags.
       uword tags = 0;
       tags = RawObject::SizeTag::update(type_args_size, tags);
       tags = RawObject::ClassTag::update(ita_cls.index(), tags);
       __ movq(Address(RCX, Instance::tags_offset()), Immediate(tags));
       // Set the new InstantiatedTypeArguments object (RCX) as the type
       // arguments (RDI) of the new object (RAX).
       __ movq(RDI, RCX);
       __ addq(RDI, Immediate(kHeapObjectTag));
       // Set RBX to new object end.
       __ movq(RBX, RCX);
       __ Bind(&type_arguments_ready);
       // RAX: new object.
       // RDI: new object type arguments.
     }
 
-    // Initialize the class field in the object.
     // RAX: new object start.
     // RBX: next object start.
     // RDI: new object type arguments (if is_cls_parameterized).
     __ LoadObject(RDX, cls);  // Load class of object to be allocated.
-    __ movq(Address(RAX, Instance::class_offset()), RDX);
     // Set the tags.
     uword tags = 0;
     tags = RawObject::SizeTag::update(instance_size, tags);
     ASSERT(cls.index() != kIllegalObjectKind);
     tags = RawObject::ClassTag::update(cls.index(), tags);
     __ movq(Address(RAX, Instance::tags_offset()), Immediate(tags));
 
     // Initialize the remaining words of the object.
     const Immediate raw_null =
         Immediate(reinterpret_cast<intptr_t>(Object::null()));
@@ skipping 130 matching lines @@
       __ jmp(&slow_case);
     } else {
       __ j(ABOVE_EQUAL, &slow_case);
     }
 
     // Successfully allocated the object, now update top to point to
     // next object start and initialize the object.
     __ movq(RDI, Immediate(heap->TopAddress()));
     __ movq(Address(RDI, 0), R13);
 
-    // Initialize the class field in the object.
     // RAX: new closure object.
     // RBX: new context object (only if is_implicit_closure).
-    __ LoadObject(R10, cls);  // Load signature class of closure.
-    __ movq(Address(RAX, Closure::class_offset()), R10);
     // Set the tags.
     uword tags = 0;
     tags = RawObject::SizeTag::update(closure_size, tags);
     tags = RawObject::ClassTag::update(cls.index(), tags);
     __ movq(Address(RAX, Closure::tags_offset()), Immediate(tags));
 
     // Initialize the function field in the object.
     // RAX: new closure object.
     // RBX: new context object (only if is_implicit_closure).
     // R13: next object start.
     __ LoadObject(R10, func);  // Load function of closure to be allocated.
     __ movq(Address(RAX, Closure::function_offset()), R10);
 
     // Setup the context for this closure.
     if (is_implicit_static_closure) {
       ObjectStore* object_store = Isolate::Current()->object_store();
       ASSERT(object_store != NULL);
       const Context& empty_context =
           Context::ZoneHandle(object_store->empty_context());
       __ LoadObject(R10, empty_context);
       __ movq(Address(RAX, Closure::context_offset()), R10);
     } else if (is_implicit_instance_closure) {
       // Initialize the new context capturing the receiver.
 
-      // Set the class field to the Context class.
       const Class& context_class = Class::ZoneHandle(Object::context_class());
-      __ LoadObject(R13, context_class);
-      __ movq(Address(RBX, Context::class_offset()), R13);
       // Set the tags.
       uword tags = 0;
       tags = RawObject::SizeTag::update(context_size, tags);
       tags = RawObject::ClassTag::update(context_class.index(), tags);
       __ movq(Address(RBX, Context::tags_offset()), Immediate(tags));
 
       // Set number of variables field to 1 (for captured receiver).
       __ movq(Address(RBX, Context::num_variables_offset()), Immediate(1));
 
       // Set isolate field to isolate of current context.
@@ skipping 287 matching lines @@
   Label not_smi;
   // Test if Smi -> load Smi class for comparison.
   __ testq(RAX, Immediate(kSmiTagMask));
   __ j(NOT_ZERO, &not_smi, Assembler::kNearJump);
   const Class& smi_class =
       Class::ZoneHandle(Isolate::Current()->object_store()->smi_class());
   __ LoadObject(RAX, smi_class);
   __ ret();
 
   __ Bind(&not_smi);
-  __ movq(RAX, FieldAddress(RAX, Object::class_offset()));
+  __ GetClassOf(RAX, RAX);
   __ ret();
 }
 
 
 // Use inline cache data array to invoke the target or continue in inline
 // cache miss handler. Stub for 1-argument check (receiver class).
 //  RCX: Inline cache data array
 //  RDX: Arguments array
 //  TOS(0): return address
 // Inline cache data array structure:
@@ skipping 77 matching lines @@
 // TOS + 3: SubtypeTestCache.
 // Result in RCX: null -> not found, otherwise result (true or false).
 static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
   ASSERT((1 <= n) && (n <= 3));
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   const intptr_t kInstantiatorTypeArgumentsInBytes = 1 * kWordSize;
   const intptr_t kInstanceOffsetInBytes = 2 * kWordSize;
   const intptr_t kCacheOffsetInBytes = 3 * kWordSize;
   __ movq(RAX, Address(RSP, kInstanceOffsetInBytes));
-  __ movq(R10, FieldAddress(RAX, Object::class_offset()));
+  __ GetClassOf(R10, RAX);
   // RAX: instance, R10: instance class.
   if (n > 1) {
     // Compute instance type arguments into R13.
     Label has_no_type_arguments;
     __ movq(R13, raw_null);
     __ movq(RDI, FieldAddress(R10,
         Class::type_arguments_instance_field_offset_offset()));
     __ cmpq(RDI, Immediate(Class::kNoTypeArguments));
     __ j(EQUAL, &has_no_type_arguments, Assembler::kNearJump);
     __ movq(R13, FieldAddress(RAX, RDI, TIMES_1, 0));
@@ skipping 74 matching lines @@
 // TOS + 2: instance.
 // TOS + 3: cache array.
 // Result in RCX: null -> not found, otherwise result (true or false).
 void StubCode::GenerateSubtype3TestCacheStub(Assembler* assembler) {
   GenerateSubtypeNTestCacheStub(assembler, 3);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64