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

runtime/vm/intermediate_language_arm64.cc

 // Copyright (c) 2014, 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_ARM64.
 #if defined(TARGET_ARCH_ARM64)
 
 #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/simulator.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, use_osr);
 
 // Generic summary for call instructions that have all arguments pushed
 // on the stack and return the result in a fixed register R0.
 LocationSummary* Instruction::MakeCallSummary(Zone* zone) {
   LocationSummary* result = new(zone) LocationSummary(
       zone, 0, 0, LocationSummary::kCall);
   result->set_out(0, Location::RegisterLocation(R0));
@@ skipping 2555 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();
       const Register value = instruction_->locs()->temp(0).reg();
       __ Comment("CheckStackOverflowSlowPathOsr");
       __ Bind(osr_entry_label());
+      ASSERT(FLAG_allow_absolute_addresses);
       __ LoadImmediate(TMP, flags_address);
       __ LoadImmediate(value, Isolate::kOsrRequest);
       __ str(value, Address(TMP));
     }
     __ 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);
@@ skipping 24 matching lines @@
  private:
   CheckStackOverflowInstr* instruction_;
   Label osr_entry_label_;
 };
 
 
 void CheckStackOverflowInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   CheckStackOverflowSlowPath* slow_path = new CheckStackOverflowSlowPath(this);
   compiler->AddSlowPathCode(slow_path);
 
-  if (compiler->is_optimizing()) {
+  if (compiler->is_optimizing() && FLAG_allow_absolute_addresses) {
     __ LoadImmediate(TMP, Isolate::Current()->stack_limit_address());
     __ ldr(TMP, Address(TMP));
   } else {
     __ LoadIsolate(TMP);
     __ ldr(TMP, Address(TMP, Isolate::stack_limit_offset()));
   }
   __ CompareRegisters(SP, TMP);
   __ b(slow_path->entry_label(), LS);
   if (compiler->CanOSRFunction() && in_loop()) {
     const Register temp = locs()->temp(0).reg();
@@ skipping 2968 matching lines @@
                                 1,
                                 locs());
   __ Drop(1);
   __ Pop(result);
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64