Add flag --always_cleared_ic_data, which forces a cleared ICData to be emitted with each IC call (i…

runtime/vm/intermediate_language_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"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/locations.h"
 #include "vm/object_store.h"
 #include "vm/parser.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 #define __ compiler->assembler()->
 
 namespace dart {
 
 DECLARE_FLAG(int, optimization_counter_threshold);
 DECLARE_FLAG(bool, trace_functions);
+DECLARE_FLAG(bool, propagate_ic_data);
 
 // 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() {
   LocationSummary* result = new LocationSummary(0, 0, LocationSummary::kCall);
   result->set_out(Location::RegisterLocation(RAX));
   return result;
 }
 
 
@@ skipping 313 matching lines @@
 
   const Immediate raw_null =
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label check_identity;
   __ cmpq(Address(RSP, 0 * kWordSize), raw_null);
   __ j(EQUAL, &check_identity, Assembler::kNearJump);
   __ cmpq(Address(RSP, 1 * kWordSize), raw_null);
   __ j(EQUAL, &check_identity, Assembler::kNearJump);
 
   ICData& equality_ic_data = ICData::ZoneHandle(original_ic_data.raw());
-  if (compiler->is_optimizing()) {
+  if (compiler->is_optimizing() && FLAG_propagate_ic_data) {
     ASSERT(!original_ic_data.IsNull());
     equality_ic_data = original_ic_data.AsUnaryClassChecks();
   } else {
     equality_ic_data = ICData::New(compiler->parsed_function().function(),
                                    operator_name,
                                    deopt_id,
                                    kNumArgumentsChecked);
   }
   compiler->GenerateInstanceCall(deopt_id,
                                  token_pos,
@@ skipping 490 matching lines @@
   const String& function_name =
       String::ZoneHandle(Symbols::New(Token::Str(kind())));
   if (!compiler->is_optimizing()) {
     compiler->AddCurrentDescriptor(PcDescriptors::kDeoptBefore,
                                    deopt_id(),
                                    token_pos());
   }
   const intptr_t kNumArguments = 2;
   const intptr_t kNumArgsChecked = 2;  // Type-feedback.
   ICData& relational_ic_data = ICData::ZoneHandle(ic_data()->raw());
-  if (compiler->is_optimizing()) {
+  if (compiler->is_optimizing() && FLAG_propagate_ic_data) {
     ASSERT(!ic_data()->IsNull());
     relational_ic_data = ic_data()->AsUnaryClassChecks();
   } else {
     relational_ic_data = ICData::New(compiler->parsed_function().function(),
                                      function_name,
                                      deopt_id(),
                                      kNumArgsChecked);
   }
   compiler->GenerateInstanceCall(deopt_id(),
                                  token_pos(),
@@ skipping 1452 matching lines @@
 
 void ShiftMintOpInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   UNIMPLEMENTED();
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64