gecko/js/src/jstracer.h

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sw=4 et tw=79 ft=cpp:
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla SpiderMonkey JavaScript 1.9 code, released
 * May 28, 2008.
 *
 * The Initial Developer of the Original Code is
 *   Brendan Eich <brendan@mozilla.org
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef jstracer_h___
#define jstracer_h___

#include "jsstddef.h"
#include "jslock.h"

namespace nanojit {
    class LIns;
    class Fragmento;
    class Fragment;
    class LirWriter;
}

/*
 * Tracker is used to keep track of values being manipulated by the 
 * interpreter during trace recording.
 */
template <typename T>
class Tracker 
{
    struct Page {
        struct Page* next;
        long base;
        T map[0];
    };
    struct Page* pagelist;
    
    long         getPageBase(const void* v) const;
    struct Page* findPage(const void* v) const;
    struct Page* addPage(const void* v);
public:    
    Tracker();
    ~Tracker();
    
    T            get(const void* v) const;
    void         set(const void* v, T i);
    void         clear();
};

class JSTraceRecorder {
public:
    struct JSFrameRegs      entryState;
    Tracker<nanojit::LIns*> tracker;
    nanojit::Fragment*      fragment;
    nanojit::LirWriter*     lir;

    JSTraceRecorder(JSFrameRegs& _entryState) {
        entryState = _entryState;
    }
};

/*
 * Trace monitor. Every runtime is associated with a trace monitor that keeps
 * track of loop frequencies for all JavaScript code loaded into that runtime.
 * For this we use a loop table. Adjacent slots in the loop table, one for each
 * loop header in a given script, are requested using lock-free synchronization
 * from the runtime-wide loop table slot space, when the script is compiled.
 *
 * The loop table also doubles as trace tree pointer table once a loop achieves
 * a certain number of iterations and we recorded a tree for that loop.
 */
struct JSTraceMonitor {
    int                     freq;
    nanojit::Fragmento*     fragmento;
    JSTraceRecorder*        recorder;
};

#define ENABLE_TRACER      true
#define TRACE_TRIGGER_MASK 0x3f

extern bool
js_StartRecording(JSContext* cx, JSFrameRegs& regs);

extern void
js_EndRecording(JSContext* cx, JSFrameRegs& regs);

#endif /* jstracer_h___ */