- Tighten assertions in the X64 assembler related to object pool usage.

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2013, 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"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 143 matching lines @@
 
 
 #define __ assembler()->
 
 
 // Fall through if bool_register contains null.
 void FlowGraphCompiler::GenerateBoolToJump(Register bool_register,
                                            Label* is_true,
                                            Label* is_false) {
   Label fall_through;
-  __ CompareObject(bool_register, Object::Handle());
+  __ CompareObject(bool_register, Object::null_object());
   __ j(EQUAL, &fall_through, Assembler::kNearJump);
   __ CompareObject(bool_register, Bool::True());
   __ j(EQUAL, is_true);
   __ jmp(is_false);
   __ Bind(&fall_through);
 }
 
 
 // Clobbers RCX.
 RawSubtypeTestCache* FlowGraphCompiler::GenerateCallSubtypeTestStub(
     TypeTestStubKind test_kind,
     Register instance_reg,
     Register type_arguments_reg,
     Register temp_reg,
     Label* is_instance_lbl,
     Label* is_not_instance_lbl) {
   const SubtypeTestCache& type_test_cache =
       SubtypeTestCache::ZoneHandle(SubtypeTestCache::New());
   __ LoadObject(temp_reg, type_test_cache, PP);
   __ pushq(temp_reg);  // Subtype test cache.
   __ pushq(instance_reg);  // Instance.
   if (test_kind == kTestTypeOneArg) {
     ASSERT(type_arguments_reg == kNoRegister);
-    __ PushObject(Object::Handle());
+    __ PushObject(Object::null_object());
     __ Call(&StubCode::Subtype1TestCacheLabel(), PP);
   } else if (test_kind == kTestTypeTwoArgs) {
     ASSERT(type_arguments_reg == kNoRegister);
-    __ PushObject(Object::Handle());
+    __ PushObject(Object::null_object());
     __ Call(&StubCode::Subtype2TestCacheLabel(), PP);
   } else if (test_kind == kTestTypeThreeArgs) {
     __ pushq(type_arguments_reg);
     __ Call(&StubCode::Subtype3TestCacheLabel(), PP);
   } else {
     UNREACHABLE();
   }
   // Result is in RCX: null -> not found, otherwise Bool::True or Bool::False.
   ASSERT(instance_reg != RCX);
   ASSERT(temp_reg != RCX);
@@ skipping 130 matching lines @@
   if (type.IsBoolType()) {
     __ cmpl(kClassIdReg, Immediate(kBoolCid));
     __ j(EQUAL, is_instance_lbl);
     __ jmp(is_not_instance_lbl);
     return false;
   }
   if (type.IsFunctionType()) {
     // Check if instance is a closure.
     __ LoadClassById(R13, kClassIdReg);
     __ movq(R13, FieldAddress(R13, Class::signature_function_offset()));
-    __ CompareObject(R13, Object::Handle());
+    __ CompareObject(R13, Object::null_object());
     __ j(NOT_EQUAL, is_instance_lbl);
   }
   // Custom checking for numbers (Smi, Mint, Bigint and Double).
   // Note that instance is not Smi (checked above).
   if (type.IsSubtypeOf(Type::Handle(Type::Number()), NULL)) {
     GenerateNumberTypeCheck(
         kClassIdReg, type, is_instance_lbl, is_not_instance_lbl);
     return false;
   }
   if (type.IsStringType()) {
@@ skipping 48 matching lines @@
     Label* is_not_instance_lbl) {
   __ Comment("UninstantiatedTypeTest");
   ASSERT(!type.IsInstantiated());
   // Skip check if destination is a dynamic type.
   if (type.IsTypeParameter()) {
     const TypeParameter& type_param = TypeParameter::Cast(type);
     // Load instantiator (or null) and instantiator type arguments on stack.
     __ movq(RDX, Address(RSP, 0));  // Get instantiator type arguments.
     // RDX: instantiator type arguments.
     // Check if type argument is dynamic.
-    __ CompareObject(RDX, Object::Handle());
+    __ CompareObject(RDX, Object::null_object());
     __ j(EQUAL, is_instance_lbl);
     // Can handle only type arguments that are instances of TypeArguments.
     // (runtime checks canonicalize type arguments).
     Label fall_through;
     __ CompareClassId(RDX, kTypeArgumentsCid);
     __ j(NOT_EQUAL, &fall_through);
     __ movq(RDI,
         FieldAddress(RDX, TypeArguments::type_at_offset(type_param.index())));
     // RDI: Concrete type of type.
     // Check if type argument is dynamic.
     __ CompareObject(RDI, Type::ZoneHandle(Type::DynamicType()));
     __ j(EQUAL,  is_instance_lbl);
-    __ CompareObject(RDI, Object::Handle());
+    __ CompareObject(RDI, Object::null_object());
     __ j(EQUAL,  is_instance_lbl);
     const Type& object_type = Type::ZoneHandle(Type::ObjectType());
     __ CompareObject(RDI, object_type);
     __ j(EQUAL,  is_instance_lbl);
 
     // For Smi check quickly against int and num interfaces.
     Label not_smi;
     __ testq(RAX, Immediate(kSmiTagMask));  // Value is Smi?
     __ j(NOT_ZERO, &not_smi, Assembler::kNearJump);
     __ CompareObject(RDI, Type::ZoneHandle(Type::IntType()));
@@ skipping 132 matching lines @@
   // If type is instantiated and non-parameterized, we can inline code
   // checking whether the tested instance is a Smi.
   if (type.IsInstantiated()) {
     // A null object is only an instance of Object and dynamic, which has
     // already been checked above (if the type is instantiated). So we can
     // return false here if the instance is null (and if the type is
     // instantiated).
     // We can only inline this null check if the type is instantiated at compile
     // time, since an uninstantiated type at compile time could be Object or
     // dynamic at run time.
-    __ CompareObject(RAX, Object::Handle());
+    __ CompareObject(RAX, Object::null_object());
     __ j(EQUAL, &is_not_instance);
   }
 
   // Generate inline instanceof test.
   SubtypeTestCache& test_cache = SubtypeTestCache::ZoneHandle();
   test_cache = GenerateInlineInstanceof(token_pos, type,
                                         &is_instance, &is_not_instance);
 
   // test_cache is null if there is no fall-through.
   Label done;
@@ skipping 59 matching lines @@
   ASSERT(token_pos >= 0);
   ASSERT(!dst_type.IsNull());
   ASSERT(dst_type.IsFinalized());
   // Assignable check is skipped in FlowGraphBuilder, not here.
   ASSERT(dst_type.IsMalformed() || dst_type.IsMalbounded() ||
          (!dst_type.IsDynamicType() && !dst_type.IsObjectType()));
   __ pushq(RCX);  // Store instantiator.
   __ pushq(RDX);  // Store instantiator type arguments.
   // A null object is always assignable and is returned as result.
   Label is_assignable, runtime_call;
-  __ CompareObject(RAX, Object::Handle());
+  __ CompareObject(RAX, Object::null_object());
   __ j(EQUAL, &is_assignable);
 
   if (!FLAG_eliminate_type_checks || dst_type.IsMalformed()) {
     // If type checks are not eliminated during the graph building then
     // a transition sentinel can be seen here.
     __ CompareObject(RAX, Object::transition_sentinel());
     __ j(EQUAL, &is_assignable);
   }
 
   // Generate throw new TypeError() if the type is malformed or malbounded.
@@ skipping 283 matching lines @@
       // to be copied to the context that is not yet allocated.
       const intptr_t computed_param_pos = kFirstLocalSlotFromFp - param_pos;
       const Address param_addr(RBP, computed_param_pos * kWordSize);
       __ movq(param_addr, RAX);
     }
     delete[] opt_param;
     delete[] opt_param_position;
     if (check_correct_named_args) {
       // Check that RDI now points to the null terminator in the arguments
       // descriptor.
-      __ LoadObject(TMP, Object::Handle(), PP);
+      __ LoadObject(TMP, Object::null_object(), PP);
       __ cmpq(Address(RDI, 0), TMP);
       __ j(EQUAL, &all_arguments_processed, Assembler::kNearJump);
     }
   } else {
     ASSERT(num_opt_pos_params > 0);
     __ movq(RCX,
             FieldAddress(R10, ArgumentsDescriptor::positional_count_offset()));
     __ SmiUntag(RCX);
     for (int i = 0; i < num_opt_pos_params; i++) {
       Label next_parameter;
@@ skipping 44 matching lines @@
   __ Bind(&all_arguments_processed);
   // Nullify originally passed arguments only after they have been copied and
   // checked, otherwise noSuchMethod would not see their original values.
   // This step can be skipped in case we decide that formal parameters are
   // implicitly final, since garbage collecting the unmodified value is not
   // an issue anymore.
 
   // R10 : arguments descriptor array.
   __ movq(RCX, FieldAddress(R10, ArgumentsDescriptor::count_offset()));
   __ SmiUntag(RCX);
-  __ LoadObject(R12, Object::Handle(), PP);
+  __ LoadObject(R12, Object::null_object(), PP);
   Label null_args_loop, null_args_loop_condition;
   __ jmp(&null_args_loop_condition, Assembler::kNearJump);
   const Address original_argument_addr(
       RBP, RCX, TIMES_8, (kParamEndSlotFromFp + 1) * kWordSize);
   __ Bind(&null_args_loop);
   __ movq(original_argument_addr, R12);
   __ Bind(&null_args_loop_condition);
   __ decq(RCX);
   __ j(POSITIVE, &null_args_loop, Assembler::kNearJump);
 }
@@ skipping 10 matching lines @@
 
 
 void FlowGraphCompiler::GenerateInlinedSetter(intptr_t offset) {
   // TOS: return address.
   // +1 : value
   // +2 : receiver.
   // Sequence node has one store node and one return NULL node.
   __ movq(RAX, Address(RSP, 2 * kWordSize));  // Receiver.
   __ movq(RBX, Address(RSP, 1 * kWordSize));  // Value.
   __ StoreIntoObject(RAX, FieldAddress(RAX, offset), RBX);
-  __ LoadObject(RAX, Object::Handle(), PP);
+  __ LoadObject(RAX, Object::null_object(), PP);
   __ ret();
 }
 
 
 void FlowGraphCompiler::EmitFrameEntry() {
   const Function& function = parsed_function().function();
   Register new_pp = kNoRegister;
   Register new_pc = kNoRegister;
   if (CanOptimizeFunction() &&
       function.is_optimizable() &&
@@ skipping 141 matching lines @@
     }
   } else if (!flow_graph().IsCompiledForOsr()) {
     CopyParameters();
   }
 
   // In unoptimized code, initialize (non-argument) stack allocated slots to
   // null.
   if (!is_optimizing() && (num_locals > 0)) {
     __ Comment("Initialize spill slots");
     const intptr_t slot_base = parsed_function().first_stack_local_index();
-    __ LoadObject(RAX, Object::Handle(), PP);
+    __ LoadObject(RAX, Object::null_object(), PP);
     for (intptr_t i = 0; i < num_locals; ++i) {
       // Subtract index i (locals lie at lower addresses than RBP).
       __ movq(Address(RBP, (slot_base - i) * kWordSize), RAX);
     }
   }
 
   if (FLAG_print_scopes) {
     // Print the function scope (again) after generating the prologue in order
     // to see annotations such as allocation indices of locals.
     if (FLAG_print_ast) {
@@ skipping 702 matching lines @@
   __ movups(reg, Address(RSP, 0));
   __ addq(RSP, Immediate(kFpuRegisterSize));
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64