[Interpreter] No longer require context machine register in bytecode handlers

src/compiler/linkage.cc

 // 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.
 
 #include "src/ast/scopes.h"
 #include "src/code-stubs.h"
 #include "src/compiler.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/linkage.h"
@@ skipping 391 matching lines @@
       CallDescriptor::kCanUseRoots |    // flags
           flags,                        // flags
       descriptor.DebugName(isolate));
 }
 
 CallDescriptor* Linkage::GetBytecodeDispatchCallDescriptor(
     Isolate* isolate, Zone* zone, const CallInterfaceDescriptor& descriptor,
     int stack_parameter_count) {
   const int register_parameter_count = descriptor.GetRegisterParameterCount();
   const int parameter_count = register_parameter_count + stack_parameter_count;
-  const int context_count = 1;
-  const size_t parameter_and_context_count =
-      static_cast<size_t>(parameter_count + context_count);
 
-  LocationSignature::Builder locations(zone, 0, parameter_and_context_count);
-  MachineSignature::Builder types(zone, 0, parameter_and_context_count);
+  LocationSignature::Builder locations(zone, 0, parameter_count);
+  MachineSignature::Builder types(zone, 0, parameter_count);
 
   // Add parameters in registers and on the stack.
   for (int i = 0; i < parameter_count; i++) {
     if (i < register_parameter_count) {
       // The first parameters go in registers.
       Register reg = descriptor.GetRegisterParameter(i);
       Representation rep =
           RepresentationFromType(descriptor.GetParameterType(i));
       locations.AddParam(regloc(reg));
       types.AddParam(reptyp(rep));
     } else {
       // The rest of the parameters go on the stack.
       int stack_slot = i - register_parameter_count - stack_parameter_count;
       locations.AddParam(LinkageLocation::ForCallerFrameSlot(stack_slot));
       types.AddParam(MachineType::AnyTagged());
     }
   }
-  // Add context.
-  locations.AddParam(regloc(kContextRegister));
-  types.AddParam(MachineType::AnyTagged());
 
   // The target for interpreter dispatches is a code entry address.
   MachineType target_type = MachineType::Pointer();
   LinkageLocation target_loc = LinkageLocation::ForAnyRegister();
   return new (zone) CallDescriptor(            // --
       CallDescriptor::kCallAddress,            // kind
       target_type,                             // target MachineType
       target_loc,                              // target location
       types.Build(),                           // machine_sig
       locations.Build(),                       // location_sig
@@ skipping 46 matching lines @@
   } else {
     DCHECK(loc == regloc(kContextRegister));
     return LinkageLocation::ForCalleeFrameSlot(Frame::kContextSlot);
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8