Remove remaining uses of null's absolute address from non-IA32.

runtime/vm/intermediate_language_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/intermediate_language.h"
 
 #include "vm/dart_entry.h"
 #include "vm/flow_graph.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_range_analysis.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 #define __ compiler->assembler()->
 
 namespace dart {
 
+DECLARE_FLAG(bool, allow_absolute_addresses);
 DECLARE_FLAG(bool, emit_edge_counters);
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(bool, throw_on_javascript_int_overflow);
 DECLARE_FLAG(bool, use_osr);
 
 // Generic summary for call instructions that have all arguments pushed
 // on the stack and return the result in a fixed register RAX.
 LocationSummary* Instruction::MakeCallSummary(Zone* zone) {
   LocationSummary* result = new(zone) LocationSummary(
       zone, 0, 0, LocationSummary::kCall);
@@ skipping 2558 matching lines @@
  public:
   explicit CheckStackOverflowSlowPath(CheckStackOverflowInstr* instruction)
       : instruction_(instruction) { }
 
   virtual void EmitNativeCode(FlowGraphCompiler* compiler) {
     if (FLAG_use_osr && osr_entry_label()->IsLinked()) {
       uword flags_address = Isolate::Current()->stack_overflow_flags_address();
       Register temp = instruction_->locs()->temp(0).reg();
       __ Comment("CheckStackOverflowSlowPathOsr");
       __ Bind(osr_entry_label());
+      ASSERT(FLAG_allow_absolute_addresses);
       __ LoadImmediate(temp, Immediate(flags_address));
       __ movq(Address(temp, 0), Immediate(Isolate::kOsrRequest));
     }
     __ Comment("CheckStackOverflowSlowPath");
     __ Bind(entry_label());
     compiler->SaveLiveRegisters(instruction_->locs());
     // pending_deoptimization_env_ is needed to generate a runtime call that
     // may throw an exception.
     ASSERT(compiler->pending_deoptimization_env_ == NULL);
     Environment* env = compiler->SlowPathEnvironmentFor(instruction_);
@@ skipping 26 matching lines @@
   Label osr_entry_label_;
 };
 
 
 void CheckStackOverflowInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   CheckStackOverflowSlowPath* slow_path = new CheckStackOverflowSlowPath(this);
   compiler->AddSlowPathCode(slow_path);
 
   Register temp = locs()->temp(0).reg();
   // Generate stack overflow check.
-  if (compiler->is_optimizing()) {
+  if (compiler->is_optimizing() && FLAG_allow_absolute_addresses) {
     __ LoadImmediate(
         temp, Immediate(Isolate::Current()->stack_limit_address()));
     __ cmpq(RSP, Address(temp, 0));
   } else {
     __ LoadIsolate(temp);
     __ cmpq(RSP, Address(temp, Isolate::stack_limit_offset()));
   }
   __ j(BELOW_EQUAL, slow_path->entry_label());
   if (compiler->CanOSRFunction() && in_loop()) {
     // In unoptimized code check the usage counter to trigger OSR at loop
@@ skipping 738 matching lines @@
   } else if (CanConvertSmi() && (value_cid == kSmiCid)) {
     EmitSmiConversion(compiler);
   } else {
     const Register box = locs()->in(0).reg();
     Label* deopt = compiler->AddDeoptStub(GetDeoptId(),
                                           ICData::kDeoptCheckClass);
     Label is_smi;
 
     if ((value()->Type()->ToNullableCid() == box_cid) &&
         value()->Type()->is_nullable()) {
-      const Immediate& raw_null =
-          Immediate(reinterpret_cast<intptr_t>(Object::null()));
-      __ cmpq(box, raw_null);
+      __ CompareObject(box, Object::null_object());
       __ j(EQUAL, deopt);
     } else {
       __ testq(box, Immediate(kSmiTagMask));
       __ j(ZERO, CanConvertSmi() ? &is_smi : deopt);
       __ CompareClassId(box, box_cid);
       __ j(NOT_EQUAL, deopt);
     }
 
     EmitLoadFromBox(compiler);
 
@@ skipping 3020 matching lines @@
   __ Drop(1);
   __ popq(result);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64