path: root/js/src/jscntxt.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=8 sts=4 et sw=4 tw=99:
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * JS execution context.
 */

#include "jscntxt.h"

#include <locale.h>
#include <stdarg.h>
#include <string.h>

#include "mozilla/DebugOnly.h"

#ifdef ANDROID
# include <android/log.h>
# include <fstream>
# include <string>
#endif  // ANDROID

#include "mozilla/Util.h"

#include "jstypes.h"
#include "jsprf.h"
#include "jsatom.h"
#include "jscompartment.h"
#include "jsdbgapi.h"
#include "jsexn.h"
#include "jsfun.h"
#include "jsgc.h"
#include "jsiter.h"
#include "jsmath.h"
#include "jsobj.h"
#include "jsopcode.h"
#include "jspubtd.h"
#include "jsscript.h"
#include "jsstr.h"
#include "jsworkers.h"
#ifdef JS_ION
#include "jit/Ion.h"
#endif

#include "gc/Marking.h"
#include "js/CharacterEncoding.h"
#include "js/MemoryMetrics.h"
#include "vm/Shape.h"
#include "yarr/BumpPointerAllocator.h"

#include "jscntxtinlines.h"
#include "jsobjinlines.h"

using namespace js;
using namespace js::gc;

using mozilla::DebugOnly;
using mozilla::PodArrayZero;
using mozilla::PodZero;
using mozilla::PointerRangeSize;

bool
js::AutoCycleDetector::init()
{
    ObjectSet &set = cx->cycleDetectorSet;
    hashsetAddPointer = set.lookupForAdd(obj);
    if (!hashsetAddPointer) {
        if (!set.add(hashsetAddPointer, obj))
            return false;
        cyclic = false;
        hashsetGenerationAtInit = set.generation();
    }
    return true;
}

js::AutoCycleDetector::~AutoCycleDetector()
{
    if (!cyclic) {
        if (hashsetGenerationAtInit == cx->cycleDetectorSet.generation())
            cx->cycleDetectorSet.remove(hashsetAddPointer);
        else
            cx->cycleDetectorSet.remove(obj);
    }
}

void
js::TraceCycleDetectionSet(JSTracer *trc, js::ObjectSet &set)
{
    for (js::ObjectSet::Enum e(set); !e.empty(); e.popFront()) {
        JSObject *prior = e.front();
        MarkObjectRoot(trc, const_cast<JSObject **>(&e.front()), "cycle detector table entry");
        if (prior != e.front())
            e.rekeyFront(e.front());
    }
}

void
NewObjectCache::clearNurseryObjects(JSRuntime *rt)
{
    for (unsigned i = 0; i < mozilla::ArrayLength(entries); ++i) {
        if (IsInsideNursery(rt, entries[i].key))
            mozilla::PodZero(&entries[i]);
    }
}

void
JSRuntime::sizeOfIncludingThis(JSMallocSizeOfFun mallocSizeOf, JS::RuntimeSizes *rtSizes)
{
    rtSizes->object = mallocSizeOf(this);

    rtSizes->atomsTable = atoms.sizeOfExcludingThis(mallocSizeOf);

    rtSizes->contexts = 0;
    for (ContextIter acx(this); !acx.done(); acx.next())
        rtSizes->contexts += acx->sizeOfIncludingThis(mallocSizeOf);

    rtSizes->dtoa = mallocSizeOf(dtoaState);

    rtSizes->temporary = tempLifoAlloc.sizeOfExcludingThis(mallocSizeOf);

    rtSizes->code = JS::CodeSizes();
    if (execAlloc_)
        execAlloc_->sizeOfCode(&rtSizes->code);

    rtSizes->regexpData = bumpAlloc_ ? bumpAlloc_->sizeOfNonHeapData() : 0;

    rtSizes->interpreterStack = interpreterStack_.sizeOfExcludingThis(mallocSizeOf);

    rtSizes->gcMarker = gcMarker.sizeOfExcludingThis(mallocSizeOf);

    rtSizes->mathCache = mathCache_ ? mathCache_->sizeOfIncludingThis(mallocSizeOf) : 0;

    rtSizes->scriptData = scriptDataTable.sizeOfExcludingThis(mallocSizeOf);
    for (ScriptDataTable::Range r = scriptDataTable.all(); !r.empty(); r.popFront())
        rtSizes->scriptData += mallocSizeOf(r.front());
}

void
JSRuntime::triggerOperationCallback()
{
    AutoLockForOperationCallback lock(this);

    /*
     * Invalidate ionTop to trigger its over-recursion check. Note this must be
     * set before interrupt, to avoid racing with js_InvokeOperationCallback,
     * into a weird state where interrupt is stuck at 0 but ionStackLimit is
     * MAXADDR.
     */
    mainThread.setIonStackLimit(-1);

    /*
     * Use JS_ATOMIC_SET in the hope that it ensures the write will become
     * immediately visible to other processors polling the flag.
     */
    JS_ATOMIC_SET(&interrupt, 1);

#ifdef JS_ION
    /* asm.js code uses a separate mechanism to halt running code. */
    TriggerOperationCallbackForAsmJSCode(this);
#endif
}

void
JSRuntime::setJitHardening(bool enabled)
{
    jitHardening = enabled;
    if (execAlloc_)
        execAlloc_->setRandomize(enabled);
}

JSC::ExecutableAllocator *
JSRuntime::createExecutableAllocator(JSContext *cx)
{
    JS_ASSERT(!execAlloc_);
    JS_ASSERT(cx->runtime() == this);

    JSC::AllocationBehavior randomize =
        jitHardening ? JSC::AllocationCanRandomize : JSC::AllocationDeterministic;
    execAlloc_ = js_new<JSC::ExecutableAllocator>(randomize);
    if (!execAlloc_)
        js_ReportOutOfMemory(cx);
    return execAlloc_;
}

WTF::BumpPointerAllocator *
JSRuntime::createBumpPointerAllocator(JSContext *cx)
{
    JS_ASSERT(!bumpAlloc_);
    JS_ASSERT(cx->runtime() == this);

    bumpAlloc_ = js_new<WTF::BumpPointerAllocator>();
    if (!bumpAlloc_)
        js_ReportOutOfMemory(cx);
    return bumpAlloc_;
}

MathCache *
JSRuntime::createMathCache(JSContext *cx)
{
    JS_ASSERT(!mathCache_);
    JS_ASSERT(cx->runtime() == this);

    MathCache *newMathCache = js_new<MathCache>();
    if (!newMathCache) {
        js_ReportOutOfMemory(cx);
        return NULL;
    }

    mathCache_ = newMathCache;
    return mathCache_;
}

void
JSCompartment::sweepCallsiteClones()
{
    if (callsiteClones.initialized()) {
        for (CallsiteCloneTable::Enum e(callsiteClones); !e.empty(); e.popFront()) {
            CallsiteCloneKey key = e.front().key;
            JSFunction *fun = e.front().value;
            if (!IsScriptMarked(&key.script) || !IsObjectMarked(&fun))
                e.removeFront();
        }
    }
}

JSFunction *
js::CloneFunctionAtCallsite(JSContext *cx, HandleFunction fun, HandleScript script, jsbytecode *pc)
{
    JS_ASSERT(cx->typeInferenceEnabled());
    JS_ASSERT(fun->nonLazyScript()->shouldCloneAtCallsite);
    JS_ASSERT(!fun->nonLazyScript()->enclosingStaticScope());
    JS_ASSERT(types::UseNewTypeForClone(fun));

    typedef CallsiteCloneKey Key;
    typedef CallsiteCloneTable Table;

    Table &table = cx->compartment()->callsiteClones;
    if (!table.initialized() && !table.init())
        return NULL;

    uint32_t offset = pc - script->code;
    void* originalScript = script;
    void* originalFun = fun;
    SkipRoot skipScript(cx, &originalScript);
    SkipRoot skipFun(cx, &originalFun);

    Table::AddPtr p = table.lookupForAdd(Key(fun, script, offset));
    SkipRoot skipHash(cx, &p); /* Prevent the hash from being poisoned. */
    if (p)
        return p->value;

    RootedObject parent(cx, fun->environment());
    RootedFunction clone(cx, CloneFunctionObject(cx, fun, parent));
    if (!clone)
        return NULL;

    /*
     * Store a link back to the original for function.caller and avoid cloning
     * clones.
     */
    clone->nonLazyScript()->shouldCloneAtCallsite = false;
    clone->nonLazyScript()->isCallsiteClone = true;
    clone->nonLazyScript()->setOriginalFunctionObject(fun);

    Key key(fun, script, offset);

    /* Recalculate the hash if script or fun have been moved. */
    if (script != originalScript || fun != originalFun) {
        p = table.lookupForAdd(key);
        JS_ASSERT(!p);
    }

    if (!table.relookupOrAdd(p, key, clone.get()))
        return NULL;

    return clone;
}

JSContext *
js::NewContext(JSRuntime *rt, size_t stackChunkSize)
{
    JS_AbortIfWrongThread(rt);

    JSContext *cx = js_new<JSContext>(rt);
    if (!cx)
        return NULL;

    if (!cx->cycleDetectorSet.init()) {
        js_delete(cx);
        return NULL;
    }

    /*
     * Here the GC lock is still held after js_InitContextThreadAndLockGC took it and
     * the GC is not running on another thread.
     */
    bool first = rt->contextList.isEmpty();
    rt->contextList.insertBack(cx);

    /*
     * If cx is the first context on this runtime, initialize well-known atoms,
     * keywords, numbers, strings and self-hosted scripts. If one of these
     * steps should fail, the runtime will be left in a partially initialized
     * state, with zeroes and nulls stored in the default-initialized remainder
     * of the struct. We'll clean the runtime up under DestroyContext, because
     * cx will be "last" as well as "first".
     */
    if (first) {
#ifdef JS_THREADSAFE
        JS_BeginRequest(cx);
#endif
        bool ok = rt->staticStrings.init(cx);
        if (ok)
            ok = InitCommonNames(cx);
        if (ok)
            ok = rt->initSelfHosting(cx);

#ifdef JS_THREADSAFE
        JS_EndRequest(cx);
#endif
        if (!ok) {
            DestroyContext(cx, DCM_NEW_FAILED);
            return NULL;
        }
    }

    JSContextCallback cxCallback = rt->cxCallback;
    if (cxCallback && !cxCallback(cx, JSCONTEXT_NEW)) {
        DestroyContext(cx, DCM_NEW_FAILED);
        return NULL;
    }

    return cx;
}

void
js::DestroyContext(JSContext *cx, DestroyContextMode mode)
{
    JSRuntime *rt = cx->runtime();
    JS_AbortIfWrongThread(rt);

#ifdef JS_THREADSAFE
    if (cx->outstandingRequests != 0)
        MOZ_CRASH();
#endif

#if (defined(JSGC_ROOT_ANALYSIS) || defined(JSGC_USE_EXACT_ROOTING)) && defined(DEBUG)
    for (int i = 0; i < THING_ROOT_LIMIT; ++i)
        JS_ASSERT(cx->thingGCRooters[i] == NULL);
#endif

    if (mode != DCM_NEW_FAILED) {
        if (JSContextCallback cxCallback = rt->cxCallback) {
            /*
             * JSCONTEXT_DESTROY callback is not allowed to fail and must
             * return true.
             */
            JS_ALWAYS_TRUE(cxCallback(cx, JSCONTEXT_DESTROY));
        }
    }

    cx->remove();
    bool last = !rt->hasContexts();
    if (last) {
        JS_ASSERT(!rt->isHeapBusy());

        /*
         * Dump remaining type inference results first. This printing
         * depends on atoms still existing.
         */
        for (CompartmentsIter c(rt); !c.done(); c.next())
            c->types.print(cx, false);

        /* Off thread ion compilations depend on atoms still existing. */
        for (CompartmentsIter c(rt); !c.done(); c.next())
            CancelOffThreadIonCompile(c, NULL);

        /* Unpin all common names before final GC. */
        FinishCommonNames(rt);

        /* Clear debugging state to remove GC roots. */
        for (CompartmentsIter c(rt); !c.done(); c.next())
            c->clearTraps(rt->defaultFreeOp());
        JS_ClearAllWatchPoints(cx);

        /* Clear the statics table to remove GC roots. */
        rt->staticStrings.finish();

        JS::PrepareForFullGC(rt);
        GC(rt, GC_NORMAL, JS::gcreason::LAST_CONTEXT);

        /*
         * Clear the self-hosted global and delete self-hosted classes *after*
         * GC, as finalizers for objects check for clasp->finalize during GC.
         */
        rt->finishSelfHosting();
    } else if (mode == DCM_FORCE_GC) {
        JS_ASSERT(!rt->isHeapBusy());
        JS::PrepareForFullGC(rt);
        GC(rt, GC_NORMAL, JS::gcreason::DESTROY_CONTEXT);
    }
    js_delete_poison(cx);
}

bool
AutoResolving::alreadyStartedSlow() const
{
    JS_ASSERT(link);
    AutoResolving *cursor = link;
    do {
        JS_ASSERT(this != cursor);
        if (object.get() == cursor->object && id.get() == cursor->id && kind == cursor->kind)
            return true;
    } while (!!(cursor = cursor->link));
    return false;
}

static void
ReportError(JSContext *cx, const char *message, JSErrorReport *reportp,
            JSErrorCallback callback, void *userRef)
{
    /*
     * Check the error report, and set a JavaScript-catchable exception
     * if the error is defined to have an associated exception.  If an
     * exception is thrown, then the JSREPORT_EXCEPTION flag will be set
     * on the error report, and exception-aware hosts should ignore it.
     */
    JS_ASSERT(reportp);
    if ((!callback || callback == js_GetErrorMessage) &&
        reportp->errorNumber == JSMSG_UNCAUGHT_EXCEPTION)
        reportp->flags |= JSREPORT_EXCEPTION;

    /*
     * Call the error reporter only if an exception wasn't raised.
     *
     * If an exception was raised, then we call the debugErrorHook
     * (if present) to give it a chance to see the error before it
     * propagates out of scope.  This is needed for compatibility
     * with the old scheme.
     */
    if (!JS_IsRunning(cx) ||
        !js_ErrorToException(cx, message, reportp, callback, userRef)) {
        js_ReportErrorAgain(cx, message, reportp);
    } else if (JSDebugErrorHook hook = cx->runtime()->debugHooks.debugErrorHook) {
        /*
         * If we've already chewed up all the C stack, don't call into the
         * error reporter since this may trigger an infinite recursion where
         * the reporter triggers an over-recursion.
         */
        int stackDummy;
        if (!JS_CHECK_STACK_SIZE(cx->mainThread().nativeStackLimit, &stackDummy))
            return;

        if (cx->errorReporter)
            hook(cx, message, reportp, cx->runtime()->debugHooks.debugErrorHookData);
    }
}

/*
 * The given JSErrorReport object have been zeroed and must not outlive
 * cx->fp() (otherwise report->originPrincipals may become invalid).
 */
static void
PopulateReportBlame(JSContext *cx, JSErrorReport *report)
{
    /*
     * Walk stack until we find a frame that is associated with a non-builtin
     * rather than a builtin frame.
     */
    NonBuiltinScriptFrameIter iter(cx);
    if (iter.done())
        return;

    report->filename = iter.script()->filename();
    report->lineno = PCToLineNumber(iter.script(), iter.pc(), &report->column);
    report->originPrincipals = iter.script()->originPrincipals;
}

/*
 * Since memory has been exhausted, avoid the normal error-handling path which
 * allocates an error object, report and callstack. If code is running, simply
 * throw the static atom "out of memory". If code is not running, call the
 * error reporter directly.
 *
 * Furthermore, callers of js_ReportOutOfMemory (viz., malloc) assume a GC does
 * not occur, so GC must be avoided or suppressed.
 */
void
js_ReportOutOfMemory(JSContext *cx)
{
    cx->runtime()->hadOutOfMemory = true;

    if (JS_IsRunning(cx)) {
        cx->setPendingException(StringValue(cx->names().outOfMemory));
        return;
    }

    /* Get the message for this error, but we don't expand any arguments. */
    const JSErrorFormatString *efs =
        js_GetLocalizedErrorMessage(cx, NULL, NULL, JSMSG_OUT_OF_MEMORY);
    const char *msg = efs ? efs->format : "Out of memory";

    /* Fill out the report, but don't do anything that requires allocation. */
    JSErrorReport report;
    PodZero(&report);
    report.flags = JSREPORT_ERROR;
    report.errorNumber = JSMSG_OUT_OF_MEMORY;
    PopulateReportBlame(cx, &report);

    /* Report the error. */
    if (JSErrorReporter onError = cx->errorReporter) {
        AutoSuppressGC suppressGC(cx);
        onError(cx, msg, &report);
    }
}

JS_FRIEND_API(void)
js_ReportOverRecursed(JSContext *maybecx)
{
#ifdef JS_MORE_DETERMINISTIC
    /*
     * We cannot make stack depth deterministic across different
     * implementations (e.g. JIT vs. interpreter will differ in
     * their maximum stack depth).
     * However, we can detect externally when we hit the maximum
     * stack depth which is useful for external testing programs
     * like fuzzers.
     */
    fprintf(stderr, "js_ReportOverRecursed called\n");
#endif
    if (maybecx)
        JS_ReportErrorNumber(maybecx, js_GetErrorMessage, NULL, JSMSG_OVER_RECURSED);
}

void
js_ReportAllocationOverflow(JSContext *maybecx)
{
    if (maybecx) {
        AutoSuppressGC suppressGC(maybecx);
        JS_ReportErrorNumber(maybecx, js_GetErrorMessage, NULL, JSMSG_ALLOC_OVERFLOW);
    }
}

/*
 * Given flags and the state of cx, decide whether we should report an
 * error, a warning, or just continue execution normally.  Return
 * true if we should continue normally, without reporting anything;
 * otherwise, adjust *flags as appropriate and return false.
 */
static bool
checkReportFlags(JSContext *cx, unsigned *flags)
{
    if (JSREPORT_IS_STRICT_MODE_ERROR(*flags)) {
        /*
         * Error in strict code; warning with extra warnings option; okay
         * otherwise.  We assume that if the top frame is a native, then it is
         * strict if the nearest scripted frame is strict, see bug 536306.
         */
        JSScript *script = cx->currentScript();
        if (script && script->strict)
            *flags &= ~JSREPORT_WARNING;
        else if (cx->hasExtraWarningsOption())
            *flags |= JSREPORT_WARNING;
        else
            return true;
    } else if (JSREPORT_IS_STRICT(*flags)) {
        /* Warning/error only when JSOPTION_STRICT is set. */
        if (!cx->hasExtraWarningsOption())
            return true;
    }

    /* Warnings become errors when JSOPTION_WERROR is set. */
    if (JSREPORT_IS_WARNING(*flags) && cx->hasWErrorOption())
        *flags &= ~JSREPORT_WARNING;

    return false;
}

JSBool
js_ReportErrorVA(JSContext *cx, unsigned flags, const char *format, va_list ap)
{
    char *message;
    jschar *ucmessage;
    size_t messagelen;
    JSErrorReport report;
    JSBool warning;

    if (checkReportFlags(cx, &flags))
        return JS_TRUE;

    message = JS_vsmprintf(format, ap);
    if (!message)
        return JS_FALSE;
    messagelen = strlen(message);

    PodZero(&report);
    report.flags = flags;
    report.errorNumber = JSMSG_USER_DEFINED_ERROR;
    report.ucmessage = ucmessage = InflateString(cx, message, &messagelen);
    PopulateReportBlame(cx, &report);

    warning = JSREPORT_IS_WARNING(report.flags);

    ReportError(cx, message, &report, NULL, NULL);
    js_free(message);
    js_free(ucmessage);
    return warning;
}

/* |callee| requires a usage string provided by JS_DefineFunctionsWithHelp. */
void
js::ReportUsageError(JSContext *cx, HandleObject callee, const char *msg)
{
    const char *usageStr = "usage";
    PropertyName *usageAtom = Atomize(cx, usageStr, strlen(usageStr))->asPropertyName();
    RootedId id(cx, NameToId(usageAtom));
    DebugOnly<Shape *> shape = static_cast<Shape *>(callee->nativeLookup(cx, id));
    JS_ASSERT(!shape->configurable());
    JS_ASSERT(!shape->writable());
    JS_ASSERT(shape->hasDefaultGetter());

    RootedValue usage(cx);
    if (!JS_LookupProperty(cx, callee, "usage", usage.address()))
        return;

    if (JSVAL_IS_VOID(usage)) {
        JS_ReportError(cx, "%s", msg);
    } else {
        JSString *str = JSVAL_TO_STRING(usage);
        JS::Anchor<JSString *> a_str(str);
        const jschar *chars = JS_GetStringCharsZ(cx, str);
        if (!chars)
            return;
        JS_ReportError(cx, "%s. Usage: %hs", msg, chars);
    }
}

bool
js::PrintError(JSContext *cx, FILE *file, const char *message, JSErrorReport *report,
               bool reportWarnings)
{
    if (!report) {
        fprintf(file, "%s\n", message);
        fflush(file);
        return false;
    }

    /* Conditionally ignore reported warnings. */
    if (JSREPORT_IS_WARNING(report->flags) && !reportWarnings)
        return false;

    char *prefix = NULL;
    if (report->filename)
        prefix = JS_smprintf("%s:", report->filename);
    if (report->lineno) {
        char *tmp = prefix;
        prefix = JS_smprintf("%s%u:%u ", tmp ? tmp : "", report->lineno, report->column);
        JS_free(cx, tmp);
    }
    if (JSREPORT_IS_WARNING(report->flags)) {
        char *tmp = prefix;
        prefix = JS_smprintf("%s%swarning: ",
                             tmp ? tmp : "",
                             JSREPORT_IS_STRICT(report->flags) ? "strict " : "");
        JS_free(cx, tmp);
    }

    /* embedded newlines -- argh! */
    const char *ctmp;
    while ((ctmp = strchr(message, '\n')) != 0) {
        ctmp++;
        if (prefix)
            fputs(prefix, file);
        fwrite(message, 1, ctmp - message, file);
        message = ctmp;
    }

    /* If there were no filename or lineno, the prefix might be empty */
    if (prefix)
        fputs(prefix, file);
    fputs(message, file);

    if (report->linebuf) {
        /* report->linebuf usually ends with a newline. */
        int n = strlen(report->linebuf);
        fprintf(file, ":\n%s%s%s%s",
                prefix,
                report->linebuf,
                (n > 0 && report->linebuf[n-1] == '\n') ? "" : "\n",
                prefix);
        n = report->tokenptr - report->linebuf;
        for (int i = 0, j = 0; i < n; i++) {
            if (report->linebuf[i] == '\t') {
                for (int k = (j + 8) & ~7; j < k; j++) {
                    fputc('.', file);
                }
                continue;
            }
            fputc('.', file);
            j++;
        }
        fputc('^', file);
    }
    fputc('\n', file);
    fflush(file);
    JS_free(cx, prefix);
    return true;
}

char *
js_strdup(JSContext *cx, const char *s)
{
    size_t n = strlen(s) + 1;
    void *p = cx->malloc_(n);
    if (!p)
        return NULL;
    return (char *)js_memcpy(p, s, n);
}

/*
 * The arguments from ap need to be packaged up into an array and stored
 * into the report struct.
 *
 * The format string addressed by the error number may contain operands
 * identified by the format {N}, where N is a decimal digit. Each of these
 * is to be replaced by the Nth argument from the va_list. The complete
 * message is placed into reportp->ucmessage converted to a JSString.
 *
 * Returns true if the expansion succeeds (can fail if out of memory).
 */
JSBool
js_ExpandErrorArguments(JSContext *cx, JSErrorCallback callback,
                        void *userRef, const unsigned errorNumber,
                        char **messagep, JSErrorReport *reportp,
                        ErrorArgumentsType argumentsType, va_list ap)
{
    const JSErrorFormatString *efs;
    int i;
    int argCount;
    bool messageArgsPassed = !!reportp->messageArgs;

    *messagep = NULL;

    /* Most calls supply js_GetErrorMessage; if this is so, assume NULL. */
    if (!callback || callback == js_GetErrorMessage)
        efs = js_GetLocalizedErrorMessage(cx, userRef, NULL, errorNumber);
    else
        efs = callback(userRef, NULL, errorNumber);
    if (efs) {
        reportp->exnType = efs->exnType;

        size_t totalArgsLength = 0;
        size_t argLengths[10]; /* only {0} thru {9} supported */
        argCount = efs->argCount;
        JS_ASSERT(argCount <= 10);
        if (argCount > 0) {
            /*
             * Gather the arguments into an array, and accumulate
             * their sizes. We allocate 1 more than necessary and
             * null it out to act as the caboose when we free the
             * pointers later.
             */
            if (messageArgsPassed) {
                JS_ASSERT(!reportp->messageArgs[argCount]);
            } else {
                reportp->messageArgs = cx->pod_malloc<const jschar*>(argCount + 1);
                if (!reportp->messageArgs)
                    return JS_FALSE;
                /* NULL-terminate for easy copying. */
                reportp->messageArgs[argCount] = NULL;
            }
            for (i = 0; i < argCount; i++) {
                if (messageArgsPassed) {
                    /* Do nothing. */
                } else if (argumentsType == ArgumentsAreASCII) {
                    char *charArg = va_arg(ap, char *);
                    size_t charArgLength = strlen(charArg);
                    reportp->messageArgs[i] = InflateString(cx, charArg, &charArgLength);
                    if (!reportp->messageArgs[i])
                        goto error;
                } else {
                    reportp->messageArgs[i] = va_arg(ap, jschar *);
                }
                argLengths[i] = js_strlen(reportp->messageArgs[i]);
                totalArgsLength += argLengths[i];
            }
        }
        /*
         * Parse the error format, substituting the argument X
         * for {X} in the format.
         */
        if (argCount > 0) {
            if (efs->format) {
                jschar *buffer, *fmt, *out;
                int expandedArgs = 0;
                size_t expandedLength;
                size_t len = strlen(efs->format);

                buffer = fmt = InflateString(cx, efs->format, &len);
                if (!buffer)
                    goto error;
                expandedLength = len
                                 - (3 * argCount)       /* exclude the {n} */
                                 + totalArgsLength;

                /*
                * Note - the above calculation assumes that each argument
                * is used once and only once in the expansion !!!
                */
                reportp->ucmessage = out = cx->pod_malloc<jschar>(expandedLength + 1);
                if (!out) {
                    js_free(buffer);
                    goto error;
                }
                while (*fmt) {
                    if (*fmt == '{') {
                        if (isdigit(fmt[1])) {
                            int d = JS7_UNDEC(fmt[1]);
                            JS_ASSERT(d < argCount);
                            js_strncpy(out, reportp->messageArgs[d],
                                       argLengths[d]);
                            out += argLengths[d];
                            fmt += 3;
                            expandedArgs++;
                            continue;
                        }
                    }
                    *out++ = *fmt++;
                }
                JS_ASSERT(expandedArgs == argCount);
                *out = 0;
                js_free(buffer);
                TwoByteChars ucmsg(reportp->ucmessage,
                                   PointerRangeSize(static_cast<const jschar *>(reportp->ucmessage),
                                                    static_cast<const jschar *>(out)));
                *messagep = LossyTwoByteCharsToNewLatin1CharsZ(cx, ucmsg).c_str();
                if (!*messagep)
                    goto error;
            }
        } else {
            /* Non-null messageArgs should have at least one non-null arg. */
            JS_ASSERT(!reportp->messageArgs);
            /*
             * Zero arguments: the format string (if it exists) is the
             * entire message.
             */
            if (efs->format) {
                size_t len;
                *messagep = JS_strdup(cx, efs->format);
                if (!*messagep)
                    goto error;
                len = strlen(*messagep);
                reportp->ucmessage = InflateString(cx, *messagep, &len);
                if (!reportp->ucmessage)
                    goto error;
            }
        }
    }
    if (*messagep == NULL) {
        /* where's the right place for this ??? */
        const char *defaultErrorMessage
            = "No error message available for error number %d";
        size_t nbytes = strlen(defaultErrorMessage) + 16;
        *messagep = cx->pod_malloc<char>(nbytes);
        if (!*messagep)
            goto error;
        JS_snprintf(*messagep, nbytes, defaultErrorMessage, errorNumber);
    }
    return JS_TRUE;

error:
    if (!messageArgsPassed && reportp->messageArgs) {
        /* free the arguments only if we allocated them */
        if (argumentsType == ArgumentsAreASCII) {
            i = 0;
            while (reportp->messageArgs[i])
                js_free((void *)reportp->messageArgs[i++]);
        }
        js_free((void *)reportp->messageArgs);
        reportp->messageArgs = NULL;
    }
    if (reportp->ucmessage) {
        js_free((void *)reportp->ucmessage);
        reportp->ucmessage = NULL;
    }
    if (*messagep) {
        js_free((void *)*messagep);
        *messagep = NULL;
    }
    return JS_FALSE;
}

JSBool
js_ReportErrorNumberVA(JSContext *cx, unsigned flags, JSErrorCallback callback,
                       void *userRef, const unsigned errorNumber,
                       ErrorArgumentsType argumentsType, va_list ap)
{
    JSErrorReport report;
    char *message;
    JSBool warning;

    if (checkReportFlags(cx, &flags))
        return JS_TRUE;
    warning = JSREPORT_IS_WARNING(flags);

    PodZero(&report);
    report.flags = flags;
    report.errorNumber = errorNumber;
    PopulateReportBlame(cx, &report);

    if (!js_ExpandErrorArguments(cx, callback, userRef, errorNumber,
                                 &message, &report, argumentsType, ap)) {
        return JS_FALSE;
    }

    ReportError(cx, message, &report, callback, userRef);

    if (message)
        js_free(message);
    if (report.messageArgs) {
        /*
         * js_ExpandErrorArguments owns its messageArgs only if it had to
         * inflate the arguments (from regular |char *|s).
         */
        if (argumentsType == ArgumentsAreASCII) {
            int i = 0;
            while (report.messageArgs[i])
                js_free((void *)report.messageArgs[i++]);
        }
        js_free((void *)report.messageArgs);
    }
    if (report.ucmessage)
        js_free((void *)report.ucmessage);

    return warning;
}

bool
js_ReportErrorNumberUCArray(JSContext *cx, unsigned flags, JSErrorCallback callback,
                            void *userRef, const unsigned errorNumber,
                            const jschar **args)
{
    if (checkReportFlags(cx, &flags))
        return true;
    bool warning = JSREPORT_IS_WARNING(flags);

    JSErrorReport report;
    PodZero(&report);
    report.flags = flags;
    report.errorNumber = errorNumber;
    PopulateReportBlame(cx, &report);
    report.messageArgs = args;

    char *message;
    va_list dummy;
    if (!js_ExpandErrorArguments(cx, callback, userRef, errorNumber,
                                 &message, &report, ArgumentsAreUnicode, dummy)) {
        return false;
    }

    ReportError(cx, message, &report, callback, userRef);

    if (message)
        js_free(message);
    if (report.ucmessage)
        js_free((void *)report.ucmessage);

    return warning;
}

JS_FRIEND_API(void)
js_ReportErrorAgain(JSContext *cx, const char *message, JSErrorReport *reportp)
{
    JSErrorReporter onError;

    if (!message)
        return;

    onError = cx->errorReporter;

    /*
     * If debugErrorHook is present then we give it a chance to veto
     * sending the error on to the regular ErrorReporter.
     */
    if (onError) {
        JSDebugErrorHook hook = cx->runtime()->debugHooks.debugErrorHook;
        if (hook && !hook(cx, message, reportp, cx->runtime()->debugHooks.debugErrorHookData))
            onError = NULL;
    }
    if (onError)
        onError(cx, message, reportp);
}

void
js_ReportIsNotDefined(JSContext *cx, const char *name)
{
    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_NOT_DEFINED, name);
}

JSBool
js_ReportIsNullOrUndefined(JSContext *cx, int spindex, HandleValue v,
                           HandleString fallback)
{
    char *bytes;
    JSBool ok;

    bytes = DecompileValueGenerator(cx, spindex, v, fallback);
    if (!bytes)
        return JS_FALSE;

    if (strcmp(bytes, js_undefined_str) == 0 ||
        strcmp(bytes, js_null_str) == 0) {
        ok = JS_ReportErrorFlagsAndNumber(cx, JSREPORT_ERROR,
                                          js_GetErrorMessage, NULL,
                                          JSMSG_NO_PROPERTIES, bytes,
                                          NULL, NULL);
    } else if (v.isUndefined()) {
        ok = JS_ReportErrorFlagsAndNumber(cx, JSREPORT_ERROR,
                                          js_GetErrorMessage, NULL,
                                          JSMSG_UNEXPECTED_TYPE, bytes,
                                          js_undefined_str, NULL);
    } else {
        JS_ASSERT(v.isNull());
        ok = JS_ReportErrorFlagsAndNumber(cx, JSREPORT_ERROR,
                                          js_GetErrorMessage, NULL,
                                          JSMSG_UNEXPECTED_TYPE, bytes,
                                          js_null_str, NULL);
    }

    js_free(bytes);
    return ok;
}

void
js_ReportMissingArg(JSContext *cx, HandleValue v, unsigned arg)
{
    char argbuf[11];
    char *bytes;
    RootedAtom atom(cx);

    JS_snprintf(argbuf, sizeof argbuf, "%u", arg);
    bytes = NULL;
    if (IsFunctionObject(v)) {
        atom = v.toObject().as<JSFunction>().atom();
        bytes = DecompileValueGenerator(cx, JSDVG_SEARCH_STACK,
                                        v, atom);
        if (!bytes)
            return;
    }
    JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL,
                         JSMSG_MISSING_FUN_ARG, argbuf,
                         bytes ? bytes : "");
    js_free(bytes);
}

JSBool
js_ReportValueErrorFlags(JSContext *cx, unsigned flags, const unsigned errorNumber,
                         int spindex, HandleValue v, HandleString fallback,
                         const char *arg1, const char *arg2)
{
    char *bytes;
    JSBool ok;

    JS_ASSERT(js_ErrorFormatString[errorNumber].argCount >= 1);
    JS_ASSERT(js_ErrorFormatString[errorNumber].argCount <= 3);
    bytes = DecompileValueGenerator(cx, spindex, v, fallback);
    if (!bytes)
        return JS_FALSE;

    ok = JS_ReportErrorFlagsAndNumber(cx, flags, js_GetErrorMessage,
                                      NULL, errorNumber, bytes, arg1, arg2);
    js_free(bytes);
    return ok;
}

const JSErrorFormatString js_ErrorFormatString[JSErr_Limit] = {
#define MSG_DEF(name, number, count, exception, format) \
    { format, count, exception } ,
#include "js.msg"
#undef MSG_DEF
};

JS_FRIEND_API(const JSErrorFormatString *)
js_GetErrorMessage(void *userRef, const char *locale, const unsigned errorNumber)
{
    if ((errorNumber > 0) && (errorNumber < JSErr_Limit))
        return &js_ErrorFormatString[errorNumber];
    return NULL;
}

JSBool
js_InvokeOperationCallback(JSContext *cx)
{
    JS_ASSERT_REQUEST_DEPTH(cx);

    JSRuntime *rt = cx->runtime();
    JS_ASSERT(rt->interrupt != 0);

    /*
     * Reset the callback counter first, then run GC and yield. If another
     * thread is racing us here we will accumulate another callback request
     * which will be serviced at the next opportunity.
     */
    JS_ATOMIC_SET(&rt->interrupt, 0);

    /* IonMonkey sets its stack limit to UINTPTR_MAX to trigger operaton callbacks. */
    rt->resetIonStackLimit();

    if (rt->gcIsNeeded)
        GCSlice(rt, GC_NORMAL, rt->gcTriggerReason);

#ifdef JSGC_GENERATIONAL
    if (rt->gcStoreBuffer.isAboutToOverflow())
        MinorGC(rt, JS::gcreason::FULL_STORE_BUFFER);
#endif

#ifdef JS_ION
    /*
     * A worker thread may have set the callback after finishing an Ion
     * compilation.
     */
    jit::AttachFinishedCompilations(cx);
#endif

    /*
     * Important: Additional callbacks can occur inside the callback handler
     * if it re-enters the JS engine. The embedding must ensure that the
     * callback is disconnected before attempting such re-entry.
     */
    JSOperationCallback cb = cx->operationCallback;
    return !cb || cb(cx);
}

JSBool
js_HandleExecutionInterrupt(JSContext *cx)
{
    JSBool result = JS_TRUE;
    if (cx->runtime()->interrupt)
        result = js_InvokeOperationCallback(cx) && result;
    return result;
}

js::ThreadSafeContext::ThreadSafeContext(JSRuntime *rt, PerThreadData *pt, ContextKind kind)
  : ContextFriendFields(rt),
    contextKind_(kind),
    perThreadData(pt)
{ }

bool
ThreadSafeContext::isJSContext() const
{
    return contextKind_ == Context_JS;
}

JSContext *
ThreadSafeContext::asJSContext()
{
    JS_ASSERT(isJSContext());
    return reinterpret_cast<JSContext *>(this);
}

bool
ThreadSafeContext::isForkJoinSlice() const
{
    return contextKind_ == Context_ForkJoin;
}

ForkJoinSlice *
ThreadSafeContext::asForkJoinSlice()
{
    JS_ASSERT(isForkJoinSlice());
    return reinterpret_cast<ForkJoinSlice *>(this);
}

JSContext::JSContext(JSRuntime *rt)
  : ThreadSafeContext(rt, &rt->mainThread, Context_JS),
    throwing(false),
    exception(UndefinedValue()),
    options_(0),
    reportGranularity(JS_DEFAULT_JITREPORT_GRANULARITY),
    resolvingList(NULL),
    generatingError(false),
    enterCompartmentDepth_(0),
    savedFrameChains_(),
    defaultCompartmentObject_(NULL),
    cycleDetectorSet(thisDuringConstruction()),
    errorReporter(NULL),
    operationCallback(NULL),
    data(NULL),
    data2(NULL),
#ifdef JS_THREADSAFE
    outstandingRequests(0),
#endif
    resolveFlags(0),
    iterValue(MagicValue(JS_NO_ITER_VALUE)),
    jitIsBroken(false),
#ifdef MOZ_TRACE_JSCALLS
    functionCallback(NULL),
#endif
    innermostGenerator_(NULL)
{
#ifdef DEBUG
    stackIterAssertionEnabled = true;
#endif

    JS_ASSERT(static_cast<ContextFriendFields*>(this) ==
              ContextFriendFields::get(this));

#if defined(JSGC_ROOT_ANALYSIS) || defined(JSGC_USE_EXACT_ROOTING)
    PodArrayZero(thingGCRooters);
#endif
#if defined(DEBUG) && defined(JS_GC_ZEAL) && defined(JSGC_ROOT_ANALYSIS) && !defined(JS_THREADSAFE)
    skipGCRooters = NULL;
#endif
}

JSContext::~JSContext()
{
    /* Free the stuff hanging off of cx. */
    JS_ASSERT(!resolvingList);
}

bool
JSRuntime::setDefaultLocale(const char *locale)
{
    if (!locale)
        return false;
    resetDefaultLocale();
    defaultLocale = JS_strdup(this, locale);
    return defaultLocale != NULL;
}

void
JSRuntime::resetDefaultLocale()
{
    js_free(defaultLocale);
    defaultLocale = NULL;
}

const char *
JSRuntime::getDefaultLocale()
{
    if (defaultLocale)
        return defaultLocale;

    char *locale, *lang, *p;
#ifdef HAVE_SETLOCALE
    locale = setlocale(LC_ALL, NULL);
#else
    locale = getenv("LANG");
#endif
    // convert to a well-formed BCP 47 language tag
    if (!locale || !strcmp(locale, "C"))
        locale = const_cast<char*>("und");
    lang = JS_strdup(this, locale);
    if (!lang)
        return NULL;
    if ((p = strchr(lang, '.')))
        *p = '\0';
    while ((p = strchr(lang, '_')))
        *p = '-';

    defaultLocale = lang;
    return defaultLocale;
}

/*
 * Since this function is only called in the context of a pending exception,
 * the caller must subsequently take an error path. If wrapping fails, it will
 * set a new (uncatchable) exception to be used in place of the original.
 */
void
JSContext::wrapPendingException()
{
    RootedValue value(this, getPendingException());
    clearPendingException();
    if (!IsAtomsCompartment(compartment()) && compartment()->wrap(this, &value))
        setPendingException(value);
}


void
JSContext::enterGenerator(JSGenerator *gen)
{
    JS_ASSERT(!gen->prevGenerator);
    gen->prevGenerator = innermostGenerator_;
    innermostGenerator_ = gen;
}

void
JSContext::leaveGenerator(JSGenerator *gen)
{
    JS_ASSERT(innermostGenerator_ == gen);
    innermostGenerator_ = innermostGenerator_->prevGenerator;
    gen->prevGenerator = NULL;
}


bool
JSContext::runningWithTrustedPrincipals() const
{
    return !compartment() || compartment()->principals == runtime()->trustedPrincipals();
}

bool
JSContext::saveFrameChain()
{
    if (!savedFrameChains_.append(SavedFrameChain(compartment(), enterCompartmentDepth_)))
        return false;

    if (Activation *act = mainThread().activation())
        act->saveFrameChain();

    setCompartment(NULL);
    enterCompartmentDepth_ = 0;

    return true;
}

void
JSContext::restoreFrameChain()
{
    SavedFrameChain sfc = savedFrameChains_.popCopy();
    setCompartment(sfc.compartment);
    enterCompartmentDepth_ = sfc.enterCompartmentCount;

    if (Activation *act = mainThread().activation())
        act->restoreFrameChain();

    if (isExceptionPending())
        wrapPendingException();
}

bool
JSContext::currentlyRunning() const
{
    for (ActivationIterator iter(runtime()); !iter.done(); ++iter) {
        if (iter.activation()->cx() == this) {
            if (iter.activation()->hasSavedFrameChain())
                return false;
            return true;
        }
    }

    return false;
}

void
JSRuntime::setGCMaxMallocBytes(size_t value)
{
    /*
     * For compatibility treat any value that exceeds PTRDIFF_T_MAX to
     * mean that value.
     */
    gcMaxMallocBytes = (ptrdiff_t(value) >= 0) ? value : size_t(-1) >> 1;
    for (ZonesIter zone(this); !zone.done(); zone.next())
        zone->setGCMaxMallocBytes(value);
}

void
JSRuntime::updateMallocCounter(size_t nbytes)
{
    updateMallocCounter(NULL, nbytes);
}

void
JSRuntime::updateMallocCounter(JS::Zone *zone, size_t nbytes)
{
    /* We tolerate any thread races when updating gcMallocBytes. */
    ptrdiff_t oldCount = gcMallocBytes;
    ptrdiff_t newCount = oldCount - ptrdiff_t(nbytes);
    gcMallocBytes = newCount;
    if (JS_UNLIKELY(newCount <= 0 && oldCount > 0))
        onTooMuchMalloc();
    else if (zone)
        zone->updateMallocCounter(nbytes);
}

JS_FRIEND_API(void)
JSRuntime::onTooMuchMalloc()
{
    TriggerGC(this, JS::gcreason::TOO_MUCH_MALLOC);
}

JS_FRIEND_API(void *)
JSRuntime::onOutOfMemory(void *p, size_t nbytes)
{
    return onOutOfMemory(p, nbytes, NULL);
}

JS_FRIEND_API(void *)
JSRuntime::onOutOfMemory(void *p, size_t nbytes, JSContext *cx)
{
    if (isHeapBusy())
        return NULL;

    /*
     * Retry when we are done with the background sweeping and have stopped
     * all the allocations and released the empty GC chunks.
     */
    JS::ShrinkGCBuffers(this);
    gcHelperThread.waitBackgroundSweepOrAllocEnd();
    if (!p)
        p = js_malloc(nbytes);
    else if (p == reinterpret_cast<void *>(1))
        p = js_calloc(nbytes);
    else
      p = js_realloc(p, nbytes);
    if (p)
        return p;
    if (cx)
        js_ReportOutOfMemory(cx);
    return NULL;
}

static bool
ComputeIsJITBroken()
{
#if !defined(ANDROID) || defined(GONK)
    return false;
#else  // ANDROID
    if (getenv("JS_IGNORE_JIT_BROKENNESS")) {
        return false;
    }

    std::string line;

    // Check for the known-bad kernel version (2.6.29).
    std::ifstream osrelease("/proc/sys/kernel/osrelease");
    std::getline(osrelease, line);
    __android_log_print(ANDROID_LOG_INFO, "Gecko", "Detected osrelease `%s'",
                        line.c_str());

    if (line.npos == line.find("2.6.29")) {
        // We're using something other than 2.6.29, so the JITs should work.
        __android_log_print(ANDROID_LOG_INFO, "Gecko", "JITs are not broken");
        return false;
    }

    // We're using 2.6.29, and this causes trouble with the JITs on i9000.
    line = "";
    bool broken = false;
    std::ifstream cpuinfo("/proc/cpuinfo");
    do {
        if (0 == line.find("Hardware")) {
            const char* blacklist[] = {
                "SCH-I400",     // Samsung Continuum
                "SGH-T959",     // Samsung i9000, Vibrant device
                "SGH-I897",     // Samsung i9000, Captivate device
                "SCH-I500",     // Samsung i9000, Fascinate device
                "SPH-D700",     // Samsung i9000, Epic device
                "GT-I9000",     // Samsung i9000, UK/Europe device
                NULL
            };
            for (const char** hw = &blacklist[0]; *hw; ++hw) {
                if (line.npos != line.find(*hw)) {
                    __android_log_print(ANDROID_LOG_INFO, "Gecko",
                                        "Blacklisted device `%s'", *hw);
                    broken = true;
                    break;
                }
            }
            break;
        }
        std::getline(cpuinfo, line);
    } while(!cpuinfo.fail() && !cpuinfo.eof());

    __android_log_print(ANDROID_LOG_INFO, "Gecko", "JITs are %sbroken",
                        broken ? "" : "not ");

    return broken;
#endif  // ifndef ANDROID
}

static bool
IsJITBrokenHere()
{
    static bool computedIsBroken = false;
    static bool isBroken = false;
    if (!computedIsBroken) {
        isBroken = ComputeIsJITBroken();
        computedIsBroken = true;
    }
    return isBroken;
}

void
JSContext::updateJITEnabled()
{
    jitIsBroken = IsJITBrokenHere();
}

size_t
JSContext::sizeOfIncludingThis(JSMallocSizeOfFun mallocSizeOf) const
{
    /*
     * There are other JSContext members that could be measured; the following
     * ones have been found by DMD to be worth measuring.  More stuff may be
     * added later.
     */
    return mallocSizeOf(this) + cycleDetectorSet.sizeOfExcludingThis(mallocSizeOf);
}

void
JSContext::mark(JSTracer *trc)
{
    /* Stack frames and slots are traced by StackSpace::mark. */

    /* Mark other roots-by-definition in the JSContext. */
    if (defaultCompartmentObject_ && !hasOption(JSOPTION_UNROOTED_GLOBAL))
        MarkObjectRoot(trc, &defaultCompartmentObject_, "default compartment object");
    if (isExceptionPending())
        MarkValueRoot(trc, &exception, "exception");

    TraceCycleDetectionSet(trc, cycleDetectorSet);

    MarkValueRoot(trc, &iterValue, "iterValue");
}

JSVersion
JSContext::findVersion() const
{
    if (JSScript *script = currentScript(NULL, ALLOW_CROSS_COMPARTMENT))
        return script->getVersion();

    if (compartment() && compartment()->options().hasVersion)
        return compartment()->options().version;

    return runtime()->defaultVersion();
}

#if defined JS_THREADSAFE && defined DEBUG

JS::AutoCheckRequestDepth::AutoCheckRequestDepth(JSContext *cx)
    : cx(cx)
{
    JS_ASSERT(cx->runtime()->requestDepth || cx->runtime()->isHeapBusy());
    cx->runtime()->assertValidThread();
    cx->runtime()->checkRequestDepth++;
}

JS::AutoCheckRequestDepth::~AutoCheckRequestDepth()
{
    JS_ASSERT(cx->runtime()->checkRequestDepth != 0);
    cx->runtime()->checkRequestDepth--;
}

#endif

#ifdef JS_CRASH_DIAGNOSTICS
void CompartmentChecker::check(StackFrame *fp)
{
    if (fp)
        check(fp->scopeChain());
}

void CompartmentChecker::check(AbstractFramePtr frame)
{
    if (frame)
        check(frame.scopeChain());
}
#endif