Improve internal compiler API so that OSR code is never installed on function.

runtime/vm/compiler.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_COMPILER_H_
 #define RUNTIME_VM_COMPILER_H_
 
 #include "vm/allocation.h"
 #include "vm/growable_array.h"
 #include "vm/runtime_entry.h"
@@ skipping 79 matching lines @@
   //
   // Returns Error::null() if there is no compilation error.
   static RawError* Compile(const Library& library, const Script& script);
 
   // Extracts function and field symbols from the class and populates
   // the class.
   //
   // Returns Error::null() if there is no compilation error.
   static RawError* CompileClass(const Class& cls);
 
-  // Generates code for given function and sets its code field.
+  // Generates code for given function without optimization and sets its code
+  // field.
   //
+  // Returns the raw code object if compilation succeeds.  Otherwise returns a
+  // RawError.  Also installs the generated code on the function.
+  static RawObject* CompileFunction(Thread* thread, const Function& function);
   // Returns Error::null() if there is no compilation error.
-  static RawError* CompileFunction(Thread* thread, const Function& function);
   static RawError* ParseFunction(Thread* thread, const Function& function);
 
   // Generates unoptimized code if not present, current code is unchanged.
   static RawError* EnsureUnoptimizedCode(Thread* thread,
                                          const Function& function);
 
   // Generates optimized code for function.
   //
-  // Returns Error::null() if there is no compilation error.
-  // If 'result_code' is not NULL, then the generated code is returned but
-  // not installed.
-  static RawError* CompileOptimizedFunction(Thread* thread,
-                                            const Function& function,
-                                            intptr_t osr_id = kNoOSRDeoptId);
+  // Returns the code object if compilation succeeds.  Returns an Error if
+  // there is a compilation error.  If optimization fails, but there is no
+  // error, returns null.  Any generated code is installed unless we are in
+  // OSR mode.
+  static RawObject* CompileOptimizedFunction(Thread* thread,
+                                             const Function& function,
+                                             intptr_t osr_id = kNoOSRDeoptId);
 
   // Generates code for given parsed function (without parsing it again) and
   // sets its code field.
   //
   // Returns Error::null() if there is no compilation error.
   static RawError* CompileParsedFunction(ParsedFunction* parsed_function);
 
   // Generates and executes code for a given code fragment, e.g. a
   // compile time constant expression. Returns the result returned
   // by the fragment.
@@ skipping 67 matching lines @@
   Monitor* done_monitor_;   // Notify/wait that the thread is done.
 
   BackgroundCompilationQueue* function_queue_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(BackgroundCompiler);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_COMPILER_H_