Allow a ParseInfo without a script for %SetCode users

src/runtime/runtime-function.cc

Index: src/runtime/runtime-function.cc
diff --git a/src/runtime/runtime-function.cc b/src/runtime/runtime-function.cc
index 31da4a4535b97186d9154cc0cca3f6743e4a5e24..7bd94bbb29af62d2bac8a7ac108338f269fda996 100644
--- a/src/runtime/runtime-function.cc
+++ b/src/runtime/runtime-function.cc
@@ -170,6 +170,14 @@ RUNTIME_FUNCTION(Runtime_SetCode) {
   Handle<SharedFunctionInfo> target_shared(target->shared());
   Handle<SharedFunctionInfo> source_shared(source->shared());
 
+  if (FLAG_mark_shared_functions_for_tier_up) {
+    // During bootstrapping with stress-opt, it can happen that we've
+    // marked some builtin code for optimization. Defeat this, as
+    // that optimization attempt may fail on code without a script
+    // (all the %SetCode usages are like this).
+    source_shared->set_marked_for_tier_up(false);
+  }

[Leszek Swirski, 2017/02/09 13:22:33]

Hm, I'm not sure I like your solution here -- for one, it doesn't solve the
problem that the second %SetCode will clear the script of the target function,
so optimising the target function will also fail. Currently this happens to not
happen, but if the target function happened to get hot while in stress opt, it
could, and some other poor soul will have to spend the day debugging this.

+
   if (!Compiler::Compile(source, Compiler::KEEP_EXCEPTION)) {
     return isolate->heap()->exception();
   }