gecko/js/src/jsprobes.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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 * ***** 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.
 *
 * Copyright (C) 2007  Sun Microsystems, Inc. All Rights Reserved.
 *
 * Contributor(s):
 *      Brendan Eich <brendan@mozilla.org>
 *
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 * 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
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#include "jsapi.h"
#include "jsutil.h"
#include "jsatom.h"
#include "jscntxt.h"
#include "jsdbgapi.h"
#include "jsfun.h"
#include "jsinterp.h"
#include "jsobj.h"
#include "jsscript.h"
#include "jsstr.h"

#include "jsprobes.h"
#include <sys/types.h>

#define TYPEOF(cx,v)    (JSVAL_IS_NULL(v) ? JSTYPE_NULL : JS_TypeOfValue(cx,v))

using namespace js;

const char Probes::nullName[] = "(null)";

const char *
Probes::FunctionClassname(const JSFunction *fun)
{
    return (fun && !FUN_INTERPRETED(fun) && !(fun->flags & JSFUN_TRCINFO) && FUN_CLASP(fun))
           ? (char *)FUN_CLASP(fun)->name
           : nullName;
}

const char *
Probes::ScriptFilename(JSScript *script)
{
    return (script && script->filename) ? (char *)script->filename : nullName;
}

int
Probes::FunctionLineNumber(JSContext *cx, const JSFunction *fun)
{
    if (fun && FUN_INTERPRETED(fun))
        return (int) JS_GetScriptBaseLineNumber(cx, FUN_SCRIPT(fun));

    return 0;
}

/*
 * This function is used to convert function arguments and return value (jsval)
 * into the following based on each value's type tag:
 *
 *      jsval      returned
 *      -------------------
 *      STRING  -> char *
 *      INT     -> int
 *      DOUBLE  -> double *
 *      BOOLEAN -> int
 *      OBJECT  -> void *
 *
 * All are presented as void * for DTrace consumers to use, after shifting or
 * masking out the JavaScript type bits. This allows D scripts to use ints and
 * booleans directly and copyinstr() for string arguments, when types are known
 * beforehand.
 *
 * This is used by the function-args and function-rval probes, which also
 * provide raw (unmasked) jsvals should type info be useful from D scripts.
 */
#if 0
static void *
jsprobes_jsvaltovoid(JSContext *cx, const js::Value &argval)
{
    if (argval.isNull())
        return (void *)JS_TYPE_STR(JSTYPE_NULL);

    if (argval.isUndefined())
        return (void *)JS_TYPE_STR(JSTYPE_VOID);

    if (argval.isBoolean())
        return (void *)argval.toBoolean();

    if (argval.isString())
        return (void *)js_GetStringBytes(cx, argval.toString());

    if (argval.isNumber()) {
        if (argval.isInt32())
            return (void *)argval.toInt32();
        // FIXME Now what?
        //return (void *)argval.toDouble();
    }

    return argval.toGCThing();
}
#endif

const char *
Probes::FunctionName(JSContext *cx, const JSFunction *fun)
{
    if (!fun)
        return nullName;

    JSAtom *atom = fun->atom;
    if (!atom) {
        /*
         * TODO: maybe do more work here to figure out the name of the property
         * or variable that held the anonymous function that we're calling, if anyone
         * cares; an easy workaround is to just give your anonymous functions names.
         */
        return nullName;
    }

    char *name = (char *)js_GetStringBytes(cx, ATOM_TO_STRING(atom));
    return name ? name : nullName;
}

#ifdef INCLUDE_MOZILLA_DTRACE
/*
 * These functions call the DTrace macros for the JavaScript USDT probes.
 * Originally this code was inlined in the JavaScript code; however since
 * a number of operations are called, these have been placed into functions
 * to reduce any negative compiler optimization effect that the addition of
 * a number of usually unused lines of code would cause.
 */
void
Probes::enterJSFunImpl(JSContext *cx, const JSFunction *fun)
{
    JAVASCRIPT_FUNCTION_ENTRY(ScriptFilename(FUN_SCRIPT(fun)), FunctionClassname(fun),
                              FunctionName(cx, fun));
}

void
Probes::handleFunctionReturn(JSContext *cx, JSFunction *fun)
{
    JAVASCRIPT_FUNCTION_RETURN(ScriptFilename(FUN_SCRIPT(fun)), FunctionClassname(fun),
                               FunctionName(cx, fun));
}

#endif