X87: Make context register implicit for CallInterfaceDescriptors

src/x87/lithium-x87.h

Index: src/x87/lithium-x87.h
diff --git a/src/x87/lithium-x87.h b/src/x87/lithium-x87.h
index 2edc63b83348e3ea603b3ccb3a8a4e99f6520d51..1eedba1f48e7f2e29a26676778ba631445386dfd 100644
--- a/src/x87/lithium-x87.h
+++ b/src/x87/lithium-x87.h
@@ -1869,8 +1869,12 @@ class LCallWithDescriptor final : public LTemplateResultInstruction<1> {
  public:
   LCallWithDescriptor(CallInterfaceDescriptor descriptor,
                       const ZoneList<LOperand*>& operands, Zone* zone)
-      : inputs_(descriptor.GetRegisterParameterCount() + 1, zone) {
-    DCHECK(descriptor.GetRegisterParameterCount() + 1 == operands.length());
+      : inputs_(descriptor.GetRegisterParameterCount() +
+                    kImplicitRegisterParameterCount,
+                zone) {
+    DCHECK(descriptor.GetRegisterParameterCount() +
+               kImplicitRegisterParameterCount ==
+           operands.length());
     inputs_.AddAll(operands, zone);
   }
 
@@ -1878,6 +1882,10 @@ class LCallWithDescriptor final : public LTemplateResultInstruction<1> {
 
   DECLARE_HYDROGEN_ACCESSOR(CallWithDescriptor)
 
+  // The target and context are passed as implicit parameters that are not
+  // explicitly listed in the descriptor.
+  static const int kImplicitRegisterParameterCount = 2;
+
  private:
   DECLARE_CONCRETE_INSTRUCTION(CallWithDescriptor, "call-with-descriptor")