[Interpreter] Add support for parameter variables.

test/unittests/interpreter/bytecode-array-builder-unittest.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/v8.h"
 
 #include "src/interpreter/bytecode-array-builder.h"
 #include "test/unittests/test-utils.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
 
 class BytecodeArrayBuilderTest : public TestWithIsolate {
  public:
   BytecodeArrayBuilderTest() {}
   ~BytecodeArrayBuilderTest() override {}
 };
 
 
 TEST_F(BytecodeArrayBuilderTest, AllBytecodesGenerated) {
   BytecodeArrayBuilder builder(isolate());
 
   builder.set_locals_count(1);
+  builder.set_parameter_count(0);
   CHECK_EQ(builder.locals_count(), 1);
 
   // Emit constant loads.
   builder.LoadLiteral(Smi::FromInt(0))
       .LoadLiteral(Smi::FromInt(8))
       .LoadUndefined()
       .LoadNull()
       .LoadTheHole()
       .LoadTrue()
       .LoadFalse();
@@ skipping 37 matching lines @@
   CHECK_GE(scorecard[Bytecodes::ToByte(Bytecode::k##Name)], 1);
   BYTECODE_LIST(CHECK_BYTECODE_PRESENT)
 #undef CHECK_BYTECODE_PRESENT
 }
 
 
 TEST_F(BytecodeArrayBuilderTest, FrameSizesLookGood) {
   for (int locals = 0; locals < 5; locals++) {
     for (int temps = 0; temps < 3; temps++) {
       BytecodeArrayBuilder builder(isolate());
+      builder.set_parameter_count(0);
       builder.set_locals_count(locals);
       builder.Return();
 
       TemporaryRegisterScope temporaries(&builder);
       for (int i = 0; i < temps; i++) {
         temporaries.NewRegister();
       }
 
       Handle<BytecodeArray> the_array = builder.ToBytecodeArray();
       int total_registers = locals + temps;
       CHECK_EQ(the_array->frame_size(), total_registers * kPointerSize);
     }
   }
 }
 
 
 TEST_F(BytecodeArrayBuilderTest, TemporariesRecycled) {
   BytecodeArrayBuilder builder(isolate());
+  builder.set_parameter_count(0);
   builder.set_locals_count(0);
   builder.Return();
 
   int first;
   {
     TemporaryRegisterScope temporaries(&builder);
     first = temporaries.NewRegister().index();
     temporaries.NewRegister();
     temporaries.NewRegister();
     temporaries.NewRegister();
@@ skipping 16 matching lines @@
   Register the_register(index);
   CHECK_EQ(the_register.index(), index);
 
   int actual_operand = the_register.ToOperand();
   CHECK_EQ(actual_operand, operand);
 
   int actual_index = Register::FromOperand(actual_operand).index();
   CHECK_EQ(actual_index, index);
 }
 
+
+TEST_F(BytecodeArrayBuilderTest, Parameters) {
+  BytecodeArrayBuilder builder(isolate());
+  builder.set_parameter_count(10);
+  builder.set_locals_count(0);
+
+  Register param0(builder.Parameter(0));
+  Register param9(builder.Parameter(9));
+  CHECK_EQ(param9.index() - param0.index(), 9);
+}
+
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8