[turbofan] Simplifying handling of callee-cleanup stack area.

src/compiler/linkage.h

 // Copyright 2014 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.
 
 #ifndef V8_COMPILER_LINKAGE_H_
 #define V8_COMPILER_LINKAGE_H_
 
 #include "src/base/flags.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/machine-type.h"
@@ skipping 109 matching lines @@
     kNeedsNopAfterCall = 1u << 2,
     kHasExceptionHandler = 1u << 3,
     kHasLocalCatchHandler = 1u << 4,
     kSupportsTailCalls = 1u << 5,
     kPatchableCallSiteWithNop = kPatchableCallSite | kNeedsNopAfterCall
   };
   typedef base::Flags<Flag> Flags;
 
   CallDescriptor(Kind kind, MachineType target_type, LinkageLocation target_loc,
                  const MachineSignature* machine_sig,
-                 LocationSignature* location_sig, size_t js_param_count,
+                 LocationSignature* location_sig, size_t stack_param_count,
                  Operator::Properties properties,
                  RegList callee_saved_registers,
                  RegList callee_saved_fp_registers, Flags flags,
                  const char* debug_name = "")
       : kind_(kind),
         target_type_(target_type),
         target_loc_(target_loc),
         machine_sig_(machine_sig),
         location_sig_(location_sig),
-        js_param_count_(js_param_count),
+        stack_param_count_(stack_param_count),
         properties_(properties),
         callee_saved_registers_(callee_saved_registers),
         callee_saved_fp_registers_(callee_saved_fp_registers),
         flags_(flags),
         debug_name_(debug_name) {
     DCHECK(machine_sig->return_count() == location_sig->return_count());
     DCHECK(machine_sig->parameter_count() == location_sig->parameter_count());
   }
 
   // Returns the kind of this call.
   Kind kind() const { return kind_; }
 
   // Returns {true} if this descriptor is a call to a C function.
   bool IsCFunctionCall() const { return kind_ == kCallAddress; }
 
   // Returns {true} if this descriptor is a call to a JSFunction.
   bool IsJSFunctionCall() const { return kind_ == kCallJSFunction; }
 
   bool IsInterpreterDispatch() const { return kind_ == kInterpreterDispatch; }
 
   // The number of return values from this call.
   size_t ReturnCount() const { return machine_sig_->return_count(); }
 
   // The number of C parameters to this call.
   size_t CParameterCount() const { return machine_sig_->parameter_count(); }
 
-  // The number of JavaScript parameters to this call, including the receiver
-  // object.
-  size_t JSParameterCount() const { return js_param_count_; }
+  // The number of stack parameters to the call.
+  size_t StackParameterCount() const { return stack_param_count_; }
+
+  // The number of parameters to the JS function call.
+  size_t JSParameterCount() const {
+    DCHECK(IsJSFunctionCall());
+    return stack_param_count_;
+  }
 
   // The total number of inputs to this call, which includes the target,
   // receiver, context, etc.
   // TODO(titzer): this should input the framestate input too.
   size_t InputCount() const { return 1 + machine_sig_->parameter_count(); }
 
   size_t FrameStateCount() const { return NeedsFrameState() ? 1 : 0; }
 
   Flags flags() const { return flags_; }
 
@@ skipping 38 matching lines @@
   bool CanTailCall(const Node* call) const;
 
  private:
   friend class Linkage;
 
   const Kind kind_;
   const MachineType target_type_;
   const LinkageLocation target_loc_;
   const MachineSignature* const machine_sig_;
   const LocationSignature* const location_sig_;
-  const size_t js_param_count_;
+  const size_t stack_param_count_;
   const Operator::Properties properties_;
   const RegList callee_saved_registers_;
   const RegList callee_saved_fp_registers_;
   const Flags flags_;
   const char* const debug_name_;
 
   DISALLOW_COPY_AND_ASSIGN(CallDescriptor);
 };
 
 DEFINE_OPERATORS_FOR_FLAGS(CallDescriptor::Flags)
@@ skipping 94 matching lines @@
   CallDescriptor* const incoming_;
 
   DISALLOW_COPY_AND_ASSIGN(Linkage);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LINKAGE_H_