profiler/ProfilerDatabase.h

   1 /*
   2  * Copyright (C) 2012, 2013 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef ProfilerDatabase_h
  27 #define ProfilerDatabase_h
  28
  29 #include "JSCJSValue.h"
  30 #include "ProfilerBytecodes.h"
  31 #include "ProfilerCompilation.h"
  32 #include "ProfilerCompilationKind.h"
  33 #include <wtf/FastMalloc.h>
  34 #include <wtf/HashMap.h>
  35 #include <wtf/Noncopyable.h>
  36 #include <wtf/PassRefPtr.h>
  37 #include <wtf/SegmentedVector.h>
  38 #include <wtf/ThreadingPrimitives.h>
  39 #include <wtf/text/WTFString.h>
  40
  41 namespace JSC { namespace Profiler {
  42
  43 class Database {
  44     WTF_MAKE_FAST_ALLOCATED; WTF_MAKE_NONCOPYABLE(Database);
  45 public:
  46     JS_EXPORT_PRIVATE Database(VM&);
  47     JS_EXPORT_PRIVATE ~Database();
  48
  49     int databaseID() const { return m_databaseID; }
  50
  51     Bytecodes* ensureBytecodesFor(CodeBlock*);
  52     void notifyDestruction(CodeBlock*);
  53
  54     void addCompilation(PassRefPtr<Compilation>);
  55
  56     // Converts the database to a JavaScript object that is suitable for JSON stringification.
  57     // Note that it's probably a good idea to use an ExecState* associated with a global
  58     // object that is "clean" - i.e. array and object prototypes haven't had strange things
  59     // done to them. And yes, it should be appropriate to just use a globalExec here.
  60     JS_EXPORT_PRIVATE JSValue toJS(ExecState*) const;
  61
  62     // Converts the database to a JavaScript object using a private temporary global object,
  63     // and then returns the JSON representation of that object.
  64     JS_EXPORT_PRIVATE String toJSON() const;
  65
  66     // Saves the JSON representation (from toJSON()) to the given file. Returns false if the
  67     // save failed.
  68     JS_EXPORT_PRIVATE bool save(const char* filename) const;
  69
  70     void registerToSaveAtExit(const char* filename);
  71
  72 private:
  73     // Use a full-blown adaptive mutex because:
  74     // - There is only one ProfilerDatabase per VM. The size overhead of the system's
  75     //   mutex is negligible if you only have one of them.
  76     // - It's locked infrequently - once per bytecode generation, compilation, and
  77     //   code block collection - so the fact that the fast path still requires a
  78     //   function call is neglible.
  79     // - It tends to be held for a while. Currently, we hold it while generating
  80     //   Profiler::Bytecodes for a CodeBlock. That's uncommon and shouldn't affect
  81     //   performance, but if we did have contention, we would want a sensible,
  82     //   power-aware backoff. An adaptive mutex will do this as a matter of course,
  83     //   but a spinlock won't.
  84     typedef Mutex Lock;
  85     typedef MutexLocker Locker;
  86
  87
  88     void addDatabaseToAtExit();
  89     void removeDatabaseFromAtExit();
  90     void performAtExitSave() const;
  91     static Database* removeFirstAtExitDatabase();
  92     static void atExitCallback();
  93
  94     int m_databaseID;
  95     VM& m_vm;
  96     SegmentedVector<Bytecodes> m_bytecodes;
  97     HashMap<CodeBlock*, Bytecodes*> m_bytecodesMap;
  98     Vector<RefPtr<Compilation>> m_compilations;
  99     bool m_shouldSaveAtExit;
 100     CString m_atExitSaveFilename;
 101     Database* m_nextRegisteredDatabase;
 102     Lock m_lock;
 103 };
 104
 105 } } // namespace JSC::Profiler
 106
 107 #endif // ProfilerDatabase_h
 108