Fix %OptimizeFunctionOnNextCall to actually work when the function has not yet been compiled.

src/compiler.cc

 // Copyright 2012 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.
 
 #include "src/v8.h"
 
 #include "src/compiler.h"
 
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 1228 matching lines @@
   }
 
   SmartPointer<CompilationInfo> info(new CompilationInfoWithZone(function));
   Isolate* isolate = info->isolate();
   DCHECK(AllowCompilation::IsAllowed(isolate));
   VMState<COMPILER> state(isolate);
   DCHECK(!isolate->has_pending_exception());
   PostponeInterruptsScope postpone(isolate);
 
   Handle<SharedFunctionInfo> shared = info->shared_info();
-  DCHECK_NE(ScopeInfo::Empty(isolate), shared->scope_info());
+  if (ScopeInfo::Empty(isolate) == shared->scope_info()) {
+    // The function was never compiled. Compile it unoptimized first.
+    CompilationInfoWithZone nested(function);

[Yang, 2014/09/04 09:07:18]

at this point, if deopt support is not enabled, we will end up recompiling the
unoptimized code again in OptimizedCompileJob::CreateGraph. I think we can
simply remove this DCHECK and ensure that we have unoptimized code in
OptimizedCompileJob::CreateGraph.

It seems to me that OptimizedCompileJob::CreateGraph requires scope info before
it ensure we have deopt support in the unoptimized code. But I think we could
change the order: first ensure that we have unoptimized code with deopt
support;then do whatever we need that requires scope info.

Alternatively, when we compile unoptimized here, enable deopt support so that we
don't have to recompile unoptimized later.

+    if (!GetUnoptimizedCodeCommon(&nested).ToHandle(&current_code)) {
+      return MaybeHandle<Code>();
+    }
+  }
   int compiled_size = shared->end_position() - shared->start_position();
   isolate->counters()->total_compile_size()->Increment(compiled_size);
   current_code->set_profiler_ticks(0);
 
   info->SetOptimizing(osr_ast_id, current_code);
 
   if (mode == CONCURRENT) {
     if (GetOptimizedCodeLater(info.get())) {
       info.Detach();  // The background recompile job owns this now.
       return isolate->builtins()->InOptimizationQueue();
@@ skipping 119 matching lines @@
   AllowHandleDereference allow_deref;
   bool tracing_on = info()->IsStub()
       ? FLAG_trace_hydrogen_stubs
       : (FLAG_trace_hydrogen &&
          info()->closure()->PassesFilter(FLAG_trace_hydrogen_filter));
   return (tracing_on &&
       base::OS::StrChr(const_cast<char*>(FLAG_trace_phase), name_[0]) != NULL);
 }
 
 } }  // namespace v8::internal