StubCallInterfaceDescriptor takes a context register.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index 5a3f4e4c34d23aff9289bdf472104d5d0accf652..e24d39e66944995475649ed2f8014c1c339635d8 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -16,9 +16,12 @@ namespace v8 {
 namespace internal {
 
 
+InterfaceDescriptor::InterfaceDescriptor()
+    : register_param_count_(-1) { }
+
+
 CodeStubInterfaceDescriptor::CodeStubInterfaceDescriptor()
-    : register_param_count_(-1),
-      stack_parameter_count_(no_reg),
+    : stack_parameter_count_(no_reg),
       hint_stack_parameter_count_(-1),
       function_mode_(NOT_JS_FUNCTION_STUB_MODE),
       deoptimization_handler_(NULL),
@@ -27,17 +30,16 @@ CodeStubInterfaceDescriptor::CodeStubInterfaceDescriptor()
       has_miss_handler_(false) { }
 
 
-void CodeStubInterfaceDescriptor::Initialize(
+void InterfaceDescriptor::Initialize(
     int register_parameter_count,
     Register* registers,
-    Address deoptimization_handler,
-    Representation* register_param_representations,
-    int hint_stack_parameter_count,
-    StubFunctionMode function_mode) {
-  // CodeStubInterfaceDescriptor owns a copy of the registers array.
+    Representation* register_param_representations) {
   register_param_count_ = register_parameter_count;
+  // InterfaceDescriptor owns a copy of the registers array.
   register_params_.Reset(NewArray<Register>(register_parameter_count));
   for (int i = 0; i < register_parameter_count; i++) {
+    // InterfaceDescriptors have an implicit context register.
+    ASSERT(!registers[i].is(ContextRegister()));
     register_params_[i] = registers[i];
   }
 
@@ -50,6 +52,18 @@ void CodeStubInterfaceDescriptor::Initialize(
       register_param_representations_[i] = register_param_representations[i];
     }
   }
+}
+
+
+void CodeStubInterfaceDescriptor::Initialize(
+    int register_parameter_count,
+    Register* registers,
+    Address deoptimization_handler,
+    Representation* register_param_representations,
+    int hint_stack_parameter_count,
+    StubFunctionMode function_mode) {
+  InterfaceDescriptor::Initialize(register_parameter_count, registers,
+                                  register_param_representations);
 
   deoptimization_handler_ = deoptimization_handler;
 
@@ -82,19 +96,8 @@ void CallInterfaceDescriptor::Initialize(
     Register* registers,
     Representation* param_representations,
     PlatformCallInterfaceDescriptor* platform_descriptor) {
-  // CallInterfaceDescriptor owns a copy of the registers array.
-  register_param_count_ = register_parameter_count;
-  register_params_.Reset(NewArray<Register>(register_parameter_count));
-  for (int i = 0; i < register_parameter_count; i++) {
-    register_params_[i] = registers[i];
-  }
-
-  // Also the register parameter representations.
-  param_representations_.Reset(
-      NewArray<Representation>(register_parameter_count));
-  for (int i = 0; i < register_parameter_count; i++) {
-    param_representations_[i] = param_representations[i];
-  }
+  InterfaceDescriptor::Initialize(register_parameter_count, registers,
+                                  param_representations);
 
   platform_specific_descriptor_ = platform_descriptor;
 }