StubCallInterfaceDescriptor takes a context register.

src/ia32/lithium-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_IA32
 
 #include "src/hydrogen-osr.h"
 #include "src/ia32/lithium-codegen-ia32.h"
@@ skipping 1107 matching lines @@
   LOperand* function = UseFixed(instr->function(), edi);
 
   LCallJSFunction* result = new(zone()) LCallJSFunction(function);
 
   return MarkAsCall(DefineFixed(result, eax), instr, CANNOT_DEOPTIMIZE_EAGERLY);
 }
 
 
 LInstruction* LChunkBuilder::DoCallWithDescriptor(
     HCallWithDescriptor* instr) {
-  const CallInterfaceDescriptor* descriptor = instr->descriptor();
+  const InterfaceDescriptor* descriptor = instr->descriptor();
+  ZoneList<LOperand*> ops(instr->OperandCount(), zone());
+  LOperand* target = UseRegisterOrConstantAtStart(instr->target());
+  ops.Add(target, zone());
 
-  LOperand* target = UseRegisterOrConstantAtStart(instr->target());
-  ZoneList<LOperand*> ops(instr->OperandCount(), zone());
-  ops.Add(target, zone());
-  for (int i = 1; i < instr->OperandCount(); i++) {
+  if (descriptor->needs_context_register()) {
+    LOperand* context = UseFixed(instr->context(), esi);
+    ops.Add(context, zone());
+  }
+
+  int first_descriptor_index = instr->FirstDescriptorOperandIndex();
+  for (int i = first_descriptor_index; i < instr->OperandCount(); i++) {
     LOperand* op = UseFixed(instr->OperandAt(i),
-        descriptor->GetParameterRegister(i - 1));
+        descriptor->GetParameterRegister(i - first_descriptor_index));
     ops.Add(op, zone());
   }
 
   LCallWithDescriptor* result = new(zone()) LCallWithDescriptor(
       descriptor, ops, zone());
   return MarkAsCall(DefineFixed(result, eax), instr, CANNOT_DEOPTIMIZE_EAGERLY);
 }
 
 
 LInstruction* LChunkBuilder::DoInvokeFunction(HInvokeFunction* instr) {
@@ skipping 1523 matching lines @@
   LOperand* function = UseRegisterAtStart(instr->function());
   LAllocateBlockContext* result =
       new(zone()) LAllocateBlockContext(context, function);
   return MarkAsCall(DefineFixed(result, esi), instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32