[Intepreter] Always use BytecodeGraphBuilder when --turbo-from-bytecode

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index e2f71479407bccbd139518236500017f7ae0f121..f1742ad571736105136df4b752dbbf24302c9bab 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -37,6 +37,7 @@ class Compiler : public AllStatic {
  public:
   enum ClearExceptionFlag { KEEP_EXCEPTION, CLEAR_EXCEPTION };
   enum ConcurrencyMode { NOT_CONCURRENT, CONCURRENT };
+  enum CompilationTier { INTERPRETED, BASELINE, OPTIMIZED };
 
   // ===========================================================================
   // The following family of methods ensures a given function is compiled. The
@@ -65,6 +66,12 @@ class Compiler : public AllStatic {
   static bool Analyze(ParseInfo* info);
   // Adds deoptimization support, requires ParseAndAnalyze.
   static bool EnsureDeoptimizationSupport(CompilationInfo* info);
+  // Ensures that bytecode is generated.

[Michael Starzinger, 2016/07/19 16:00:07]

nit: We could add "..., calls ParseAndAnalyze internally." to the comment to
clarify that it is not required for the caller to do that.

[rmcilroy, 2016/07/20 21:48:40]

Done.

+  static bool EnsureBytecode(CompilationInfo* info);
+
+  // The next compilation tier which the function should  be compiled to for
+  // optimization.

[Michael Starzinger, 2016/07/19 16:00:07]

nit: We could add "This is used as a hint by the profiler." to clarify that the
predicate is intended to be just a hint for users of this API.

[rmcilroy, 2016/07/20 21:48:40]

Done.

+  static CompilationTier NextCompilationTier(JSFunction* function);
 
   // ===========================================================================
   // The following family of methods instantiates new functions for scripts or