When Crankshaft aborts compilation, use TurboFan next time

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index e6b5f8df550b2715e7156de2b01f7d0abd79f2ff..6f192a9434babf0d15171d2561ef10a8c1a88bc5 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -387,7 +387,18 @@ class CompilationInfo {
 
   void DisableFutureOptimization() {
     if (GetFlag(kDisableFutureOptimization) && has_shared_info()) {
-      shared_info()->DisableOptimization(bailout_reason());
+      // If Crankshaft tried to optimize this function, bailed out, and
+      // doesn't want to try again, then use TurboFan next time.
+      if (!shared_info()->dont_crankshaft()) {
+        shared_info()->set_dont_crankshaft(true);

[Michael Starzinger, 2016/03/01 14:34:56]

Just for posterity: This will also disable Crankshaft for transient reasons that
might "disappear" over time (e.g. kFunctionBeingDebugged). It will also disable
Crankshaft and favor TurboFan for reasons not specific to Crankshaft (e.g.
kOptimizedTooManyTimes). This will need to be cleaned up once we try to get
compiler.cc in shape for shipping Ignition.

[adamk, 2016/03/01 19:15:44]

The second one of these examples, kOptimizedTooManyTimes, worries me a bit: does
that have the potential to make code where we spend all our time compiling
perform even worse?

+        if (FLAG_trace_opt) {
+          PrintF("[disabled Crankshaft for ");
+          shared_info()->ShortPrint();
+          PrintF(", reason: %s]\n", GetBailoutReason(bailout_reason()));
+        }
+      } else {
+        shared_info()->DisableOptimization(bailout_reason());
+      }
     }
   }