Cleanup V8_TURBOFAN_TARGET definition.

src/compiler/pipeline.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_PIPELINE_H_
 #define V8_COMPILER_PIPELINE_H_
 
 #include "src/v8.h"
 
 #include "src/compiler.h"
 
 // Note: TODO(turbofan) implies a performance improvement opportunity,
 //   and TODO(name) implies an incomplete implementation
 
-#if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X64 || V8_TARGET_ARCH_ARM
-#ifndef _WIN64
-#define V8_TURBOFAN_TARGET 1
-#else
-#define V8_TURBOFAN_TARGET 0
-#endif
-#else
-#define V8_TURBOFAN_TARGET 0
-#endif
-
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // Clients of this interface shouldn't depend on lots of compiler internals.
 class CallDescriptor;
 class Graph;
 class Schedule;
 class SourcePositionTable;
 class Linkage;
 
 class Pipeline {
  public:
   explicit Pipeline(CompilationInfo* info) : info_(info) {}
 
   // Run the entire pipeline and generate a handle to a code object.
   Handle<Code> GenerateCode();
 
   // Run the pipeline on a machine graph and generate code. If {schedule}
   // is {NULL}, then compute a new schedule for code generation.
   Handle<Code> GenerateCodeForMachineGraph(Linkage* linkage, Graph* graph,
                                            Schedule* schedule = NULL);
 
   CompilationInfo* info() const { return info_; }
   Zone* zone() { return info_->zone(); }
   Isolate* isolate() { return info_->isolate(); }
 
+  static inline bool SupportedBackend() { return V8_TURBOFAN_BACKEND != 0; }
   static inline bool SupportedTarget() { return V8_TURBOFAN_TARGET != 0; }
 
   static inline bool VerifyGraphs() {
 #ifdef DEBUG
     return true;
 #else
     return FLAG_turbo_verify;
 #endif
   }
 
  private:
   CompilationInfo* info_;
 
   Schedule* ComputeSchedule(Graph* graph);
   void VerifyAndPrintGraph(Graph* graph, const char* phase);
   Handle<Code> GenerateCode(Linkage* linkage, Graph* graph, Schedule* schedule,
                             SourcePositionTable* source_positions);
 };
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_PIPELINE_H_