Simplify feedback vector creation and store in SharedFunctionInfo.

test/cctest/test-compiler.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 272 matching lines @@
         v8::String::NewFromUtf8(CcTest::isolate(), buffer.start());
     v8::Script::Compile(script_body, &origin)->Run();
     v8::Local<v8::Function> f =
         v8::Local<v8::Function>::Cast(context->Global()->Get(
             v8::String::NewFromUtf8(CcTest::isolate(), "f")));
     CHECK_EQ(i, f->GetScriptLineNumber());
   }
 }
 
 
+TEST(FeedbackVectorPreservedAcrossRecompiles) {
+  if (i::FLAG_always_opt || !i::FLAG_crankshaft) return;
+  i::FLAG_allow_natives_syntax = true;
+  CcTest::InitializeVM();
+  if (!CcTest::i_isolate()->use_crankshaft()) return;
+  v8::HandleScope scope(CcTest::isolate());
+
+  // Make sure function f has a call that uses a type feedback slot.
+  CompileRun("function fun() {};"
+             "fun1 = fun;"
+             "function f(a) { a(); } f(fun1);");
+
+  Handle<JSFunction> f =
+      v8::Utils::OpenHandle(
+          *v8::Handle<v8::Function>::Cast(
+              CcTest::global()->Get(v8_str("f"))));
+
+  // We shouldn't have deoptimization support. We want to recompile and
+  // verify that our feedback vector preserves information.
+  CHECK(!f->shared()->has_deoptimization_support());
+  Handle<FixedArray> feedback_vector(f->shared()->feedback_vector());
+
+  // Verify that we gathered feedback.
+  CHECK_EQ(1, feedback_vector->length());
+  CHECK(feedback_vector->get(0)->IsJSFunction());
+
+  CompileRun("%OptimizeFunctionOnNextCall(f); f(fun1);");
+
+  // Verify that the feedback is still "gathered" despite a recompilation
+  // of the full code.
+  CHECK(f->shared()->has_deoptimization_support());

[Benedikt Meurer, 2014/04/28 19:17:00]

Nit: Please also CHECK() that f is actually optimized at this point.

[mvstanton, 2014/04/30 08:31:18]

Done.

+  CHECK(f->shared()->feedback_vector()->get(0)->IsJSFunction());
+}
+
+
+TEST(FeedbackVectorUnaffectedByScopeChanges) {
+  if (i::FLAG_always_opt || !i::FLAG_lazy) return;
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+
+  CompileRun("function builder() {"
+             "  call_target = function() { return 3; };"
+             "  return (function() {"
+             "    eval('');"
+             "    return function() {"
+             "      'use strict';"
+             "      call_target();"
+             "    }"
+             "  })();"
+             "}"
+             "morphing_call = builder();");
+
+  Handle<JSFunction> f =
+      v8::Utils::OpenHandle(
+          *v8::Handle<v8::Function>::Cast(
+              CcTest::global()->Get(v8_str("morphing_call"))));
+
+  // morphing_call should have one feedback vector slot for the call to
+  // call_target().
+  CHECK_EQ(1, f->shared()->feedback_vector()->length());
+  // And yet it's not compiled.
+  CHECK(!f->shared()->is_compiled());
+
+  CompileRun("morphing_call();");
+
+  // The vector should have the same size despite the new scoping.
+  CHECK_EQ(1, f->shared()->feedback_vector()->length());
+  CHECK(f->shared()->is_compiled());
+}
+
+
 // Test that optimized code for different closures is actually shared
 // immediately by the FastNewClosureStub when run in the same context.
 TEST(OptimizedCodeSharing) {
   // Skip test if --cache-optimized-code is not activated by default because
   // FastNewClosureStub that is baked into the snapshot is incorrect.
   if (!FLAG_cache_optimized_code) return;
   FLAG_stress_compaction = false;
   FLAG_allow_natives_syntax = true;
   CcTest::InitializeVM();
   v8::HandleScope scope(CcTest::isolate());
@@ skipping 68 matching lines @@
   CompileRun("function f() { a = 12345678 }; f();");
   CheckCodeForUnsafeLiteral(GetJSFunction(context->Global(), "f"));
   CompileRun("function f(x) { a = 12345678 + x}; f(1);");
   CheckCodeForUnsafeLiteral(GetJSFunction(context->Global(), "f"));
   CompileRun("function f(x) { var arguments = 1; x += 12345678}; f(1);");
   CheckCodeForUnsafeLiteral(GetJSFunction(context->Global(), "f"));
   CompileRun("function f(x) { var arguments = 1; x = 12345678}; f(1);");
   CheckCodeForUnsafeLiteral(GetJSFunction(context->Global(), "f"));
 }
 #endif