VM: Explicitly load function and context before calling a closure.

runtime/vm/intermediate_language_ia32.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_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 5882 matching lines @@
     __ andl(EDX, Immediate(
         Smi::RawValue(true_value) - Smi::RawValue(false_value)));
     if (false_value != 0) {
       __ addl(EDX, Immediate(Smi::RawValue(false_value)));
     }
   }
 }
 
 
 LocationSummary* ClosureCallInstr::MakeLocationSummary(bool opt) const {
-  return MakeCallSummary();
+  const intptr_t kNumInputs = 1;
+  const intptr_t kNumTemps = 0;
+  LocationSummary* summary =
+      new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
+  summary->set_in(0, Location::RegisterLocation(EAX));  // Function.
+  summary->set_out(0, Location::RegisterLocation(EAX));
+  return summary;
 }
 
 
 void ClosureCallInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  // Load closure object (first argument) in EDI.
+  // Load arguments descriptors.
   intptr_t argument_count = ArgumentCount();
-  __ movl(EDI, Address(ESP, (argument_count - 1) * kWordSize));
-
-  // Load arguments descriptors.
   const Array& arguments_descriptor =
       Array::ZoneHandle(ArgumentsDescriptor::New(argument_count,
                                                  argument_names()));
   __ LoadObject(EDX, arguments_descriptor);
 
-  // Load the closure function into EAX.
-  __ movl(EAX, FieldAddress(EDI, Closure::function_offset()));
-
-  // Load closure context in CTX; note that CTX has already been preserved.
-  __ movl(CTX, FieldAddress(EDI, Closure::context_offset()));
-
   // EBX: Code (compiled code or lazy compile stub).
+  ASSERT(locs()->in(0).reg() == EAX);
   __ movl(EBX, FieldAddress(EAX, Function::code_offset()));
 
   // EAX: Function.
   // EDX: Arguments descriptor array.
   // ECX: Smi 0 (no IC data; the lazy-compile stub expects a GC-safe value).
   __ xorl(ECX, ECX);
   __ movl(EBX, FieldAddress(EBX, Code::instructions_offset()));
   __ addl(EBX, Immediate(Instructions::HeaderSize() - kHeapObjectTag));
   __ call(EBX);
   compiler->AddCurrentDescriptor(PcDescriptors::kClosureCall,
@@ skipping 49 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(ArgumentCount());  // Discard arguments.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_IA32