[turbofan] Prepare mechanism to enable TF on language subset.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index c3c14a5704d7ceef78c0c6ad5ab33bbe4af32357..8460881272523230e26057d49daecbc9625d7e11 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -375,7 +375,9 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
   DCHECK(info()->shared_info()->has_deoptimization_support());
 
   // Check the enabling conditions for TurboFan.
+  bool dont_crankshaft = info()->shared_info()->dont_crankshaft();
   if (((FLAG_turbo_asm && info()->shared_info()->asm_function()) ||
+       (dont_crankshaft && strcmp(FLAG_turbo_filter, "~~") == 0) ||

[Benedikt Meurer, 2015/05/21 10:55:03]

This broke my heart...

        info()->closure()->PassesFilter(FLAG_turbo_filter)) &&
       (FLAG_turbo_osr || !info()->is_osr())) {
     // Use TurboFan for the compilation.
@@ -402,7 +404,7 @@ OptimizedCompileJob::Status OptimizedCompileJob::CreateGraph() {
     }
   }
 
-  if (!isolate()->use_crankshaft()) {
+  if (!isolate()->use_crankshaft() || dont_crankshaft) {
     // Crankshaft is entirely disabled.
     return SetLastStatus(FAILED);
   }
@@ -738,6 +740,7 @@ static bool Renumber(ParseInfo* parse_info) {
     FunctionLiteral* lit = parse_info->function();
     shared_info->set_ast_node_count(lit->ast_node_count());
     MaybeDisableOptimization(shared_info, lit->dont_optimize_reason());
+    shared_info->set_dont_crankshaft(lit->flags()->Contains(kDontCrankshaft));
     shared_info->set_dont_cache(lit->flags()->Contains(kDontCache));
   }
   return true;