[crankshaft] Remove the useless HCallStub instruction.

src/crankshaft/hydrogen.cc

 // Copyright 2013 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/crankshaft/hydrogen.h"
 
 #include <sstream>
 
 #include "src/allocation-site-scopes.h"
 #include "src/ast/ast-numbering.h"
@@ skipping 12524 matching lines @@
   HInstruction* result = NewUncasted<HStringCharFromCode>(char_code);
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 // Fast support for SubString.
 void HOptimizedGraphBuilder::GenerateSubString(CallRuntime* call) {
   DCHECK_EQ(3, call->arguments()->length());
   CHECK_ALIVE(VisitExpressions(call->arguments()));
   PushArgumentsFromEnvironment(call->arguments()->length());
-  HCallStub* result = New<HCallStub>(CodeStub::SubString, 3);
+  Callable callable = CodeFactory::SubString(isolate());
+  HValue* stub = Add<HConstant>(callable.code());
+  HValue* values[] = {context()};
+  HInstruction* result = New<HCallWithDescriptor>(
+      stub, call->arguments()->length(), callable.descriptor(),
+      Vector<HValue*>(values, arraysize(values)));
+  result->set_type(HType::String());
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 // Support for direct calls from JavaScript to native RegExp code.
 void HOptimizedGraphBuilder::GenerateRegExpExec(CallRuntime* call) {
   DCHECK_EQ(4, call->arguments()->length());
   CHECK_ALIVE(VisitExpressions(call->arguments()));
   PushArgumentsFromEnvironment(call->arguments()->length());
-  HCallStub* result = New<HCallStub>(CodeStub::RegExpExec, 4);
+  Callable callable = CodeFactory::RegExpExec(isolate());
+  HValue* stub = Add<HConstant>(callable.code());
+  HValue* values[] = {context()};
+  HInstruction* result = New<HCallWithDescriptor>(
+      stub, call->arguments()->length(), callable.descriptor(),
+      Vector<HValue*>(values, arraysize(values)));
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 void HOptimizedGraphBuilder::GenerateRegExpFlags(CallRuntime* call) {
   DCHECK_EQ(1, call->arguments()->length());
   CHECK_ALIVE(VisitExpressions(call->arguments()));
   HValue* regexp = Pop();
   HInstruction* result =
       New<HLoadNamedField>(regexp, nullptr, HObjectAccess::ForJSRegExpFlags());
@@ skipping 979 matching lines @@
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 }  // namespace internal
 }  // namespace v8