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https://gitlab.winehq.org/wine/wine-gecko.git
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3371 lines
108 KiB
C++
3371 lines
108 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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* vim: set ts=8 sw=4 et tw=78:
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Communicator client code, released
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* March 31, 1998.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/*
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* JS Mark-and-Sweep Garbage Collector.
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*
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* This GC allocates fixed-sized things with sizes up to GC_NBYTES_MAX (see
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* jsgc.h). It allocates from a special GC arena pool with each arena allocated
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* using malloc. It uses an ideally parallel array of flag bytes to hold the
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* mark bit, finalizer type index, etc.
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*
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* XXX swizzle page to freelist for better locality of reference
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*/
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#include <stdlib.h> /* for free */
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#include <math.h>
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#include <string.h> /* for memset used when DEBUG */
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#include "jstypes.h"
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#include "jsstdint.h"
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#include "jsutil.h" /* Added by JSIFY */
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#include "jshash.h" /* Added by JSIFY */
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#include "jsbit.h"
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#include "jsclist.h"
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#include "jsprf.h"
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#include "jsapi.h"
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#include "jsatom.h"
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#include "jscntxt.h"
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#include "jsversion.h"
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#include "jsdbgapi.h"
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#include "jsexn.h"
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#include "jsfun.h"
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#include "jsgc.h"
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#include "jsinterp.h"
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#include "jsiter.h"
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#include "jslock.h"
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#include "jsnum.h"
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#include "jsobj.h"
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#include "jsparse.h"
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#include "jsscope.h"
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#include "jsscript.h"
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#include "jsstaticcheck.h"
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#include "jsstr.h"
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#include "jstask.h"
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#include "jstracer.h"
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#if JS_HAS_XML_SUPPORT
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#include "jsxml.h"
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#endif
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#ifdef INCLUDE_MOZILLA_DTRACE
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#include "jsdtracef.h"
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#endif
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/*
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* Include the headers for mmap.
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*/
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#if defined(XP_WIN)
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# include <windows.h>
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#endif
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#if defined(XP_UNIX) || defined(XP_BEOS)
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# include <unistd.h>
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# include <sys/mman.h>
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#endif
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/* On Mac OS X MAP_ANONYMOUS is not defined. */
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#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
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# define MAP_ANONYMOUS MAP_ANON
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#endif
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#if !defined(MAP_ANONYMOUS)
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# define MAP_ANONYMOUS 0
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#endif
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/*
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* Check JSTempValueUnion has the size of jsval and void * so we can
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* reinterpret jsval as void* GC-thing pointer and use JSTVU_SINGLE for
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* different GC-things.
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*/
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JS_STATIC_ASSERT(sizeof(JSTempValueUnion) == sizeof(jsval));
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JS_STATIC_ASSERT(sizeof(JSTempValueUnion) == sizeof(void *));
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/*
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* Check that JSTRACE_XML follows JSTRACE_OBJECT, JSTRACE_DOUBLE and
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* JSTRACE_STRING.
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*/
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JS_STATIC_ASSERT(JSTRACE_OBJECT == 0);
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JS_STATIC_ASSERT(JSTRACE_DOUBLE == 1);
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JS_STATIC_ASSERT(JSTRACE_STRING == 2);
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JS_STATIC_ASSERT(JSTRACE_XML == 3);
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/*
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* JS_IS_VALID_TRACE_KIND assumes that JSTRACE_STRING is the last non-xml
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* trace kind when JS_HAS_XML_SUPPORT is false.
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*/
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JS_STATIC_ASSERT(JSTRACE_STRING + 1 == JSTRACE_XML);
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/*
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* Check that we can use memset(p, 0, ...) to implement JS_CLEAR_WEAK_ROOTS.
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*/
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JS_STATIC_ASSERT(JSVAL_NULL == 0);
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/*
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* Check consistency of external string constants from JSFinalizeGCThingKind.
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*/
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JS_STATIC_ASSERT(FINALIZE_EXTERNAL_STRING_LAST - FINALIZE_EXTERNAL_STRING0 ==
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JS_EXTERNAL_STRING_LIMIT - 1);
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/*
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* A GC arena contains a fixed number of flag bits for each thing in its heap,
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* and supports O(1) lookup of a flag given its thing's address.
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*
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* To implement this, we allocate things of the same size from a GC arena
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* containing GC_ARENA_SIZE bytes aligned on GC_ARENA_SIZE boundary. The
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* following picture shows arena's layout:
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*
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* +------------------------------+--------------------+---------------+
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* | allocation area for GC thing | flags of GC things | JSGCArenaInfo |
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* +------------------------------+--------------------+---------------+
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*
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* To find the flag bits for the thing we calculate the thing index counting
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* from arena's start using:
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*
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* thingIndex = (thingAddress & GC_ARENA_MASK) / thingSize
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*
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* The details of flag's lookup depend on thing's kind. For all GC things
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* except doubles we use one byte of flags where the 4 bits determine thing's
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* type and the rest is used to implement GC marking, finalization and
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* locking. We calculate the address of flag's byte using:
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*
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* flagByteAddress =
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* (thingAddress | GC_ARENA_MASK) - sizeof(JSGCArenaInfo) - thingIndex
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*
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* where
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*
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* (thingAddress | GC_ARENA_MASK) - sizeof(JSGCArenaInfo)
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*
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* is the last byte of flags' area.
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*
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* This implies that the things are allocated from the start of their area and
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* flags are allocated from the end. This arrangement avoids a relatively
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* expensive calculation of the location of the boundary separating things and
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* flags. The boundary's offset from the start of the arena is given by:
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*
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* thingsPerArena * thingSize
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*
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* where thingsPerArena is the number of things that the arena can hold:
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*
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* (GC_ARENA_SIZE - sizeof(JSGCArenaInfo)) / (thingSize + 1).
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*
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* To allocate doubles we use a specialized arena. It can contain only numbers
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* so we do not need the type bits. Moreover, since the doubles do not require
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* a finalizer and very few of them are locked via js_LockGCThing API, we use
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* just one bit of flags per double to denote if it was marked during the
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* marking phase of the GC. The locking is implemented via a hash table. Thus
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* for doubles the flag area becomes a bitmap.
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*/
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static const jsuword GC_ARENAS_PER_CHUNK = 16;
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static const jsuword GC_ARENA_SHIFT = 12;
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static const jsuword GC_ARENA_MASK = JS_BITMASK(GC_ARENA_SHIFT);
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static const jsuword GC_ARENA_SIZE = JS_BIT(GC_ARENA_SHIFT);
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struct JSGCArenaInfo {
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/*
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* Allocation list for the arena or NULL if the arena holds double values.
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*/
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JSGCArenaList *list;
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/*
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* Pointer to the previous arena in a linked list. The arena can either
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* belong to one of JSContext.gcArenaList lists or, when it does not have
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* any allocated GC things, to the list of free arenas in the chunk with
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* head stored in JSGCChunkInfo.lastFreeArena.
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*/
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JSGCArenaInfo *prev;
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/*
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* A link field for the list of arenas with marked things that haven't yet
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* been scanned for live children. The field is encoded as arena's page to
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* to hold only the high-order arena-counting bits to share the space with
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* firstArena and arenaIndex fields. For details see comments before
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* DelayMarkingChildren.
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*/
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jsuword prevUnmarkedPage : JS_BITS_PER_WORD - GC_ARENA_SHIFT;
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/*
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* When firstArena is false, the index of arena in the chunk. When
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* firstArena is true, the index of a free arena holding JSGCChunkInfo or
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* NO_FREE_ARENAS if there are no free arenas in the chunk.
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*
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* GET_ARENA_INDEX and GET_CHUNK_INFO_INDEX are convenience macros to
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* access either of indexes.
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*/
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jsuword arenaIndex : GC_ARENA_SHIFT - 1;
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/* Flag indicating if the arena is the first in the chunk. */
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jsuword firstArena : 1;
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JSGCThing *freeList;
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union {
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/* See comments before DelayMarkingChildren. */
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jsuword unmarkedChildren;
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/* The arena has marked doubles. */
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bool hasMarkedDoubles;
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};
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};
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/* GC flag definitions, must fit in 8 bits. */
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const uint8 GCF_MARK = JS_BIT(0);
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const uint8 GCF_LOCK = JS_BIT(1); /* lock request bit in API */
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/*
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* The private JSGCThing struct, which describes a JSRuntime.gcFreeList element.
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*/
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struct JSGCThing {
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JSGCThing *link;
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};
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/*
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* Macros to convert between JSGCArenaInfo, the start address of the arena and
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* arena's page defined as (start address) >> GC_ARENA_SHIFT.
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*/
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#define ARENA_INFO_OFFSET (GC_ARENA_SIZE - (uint32) sizeof(JSGCArenaInfo))
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#define IS_ARENA_INFO_ADDRESS(arena) \
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(((jsuword) (arena) & GC_ARENA_MASK) == ARENA_INFO_OFFSET)
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#define ARENA_START_TO_INFO(arenaStart) \
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(JS_ASSERT(((arenaStart) & (jsuword) GC_ARENA_MASK) == 0), \
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(JSGCArenaInfo *) ((arenaStart) + (jsuword) ARENA_INFO_OFFSET))
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#define ARENA_INFO_TO_START(arena) \
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(JS_ASSERT(IS_ARENA_INFO_ADDRESS(arena)), \
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(jsuword) (arena) & ~(jsuword) GC_ARENA_MASK)
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#define ARENA_PAGE_TO_INFO(arenaPage) \
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(JS_ASSERT(arenaPage != 0), \
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JS_ASSERT(!((jsuword)(arenaPage) >> (JS_BITS_PER_WORD-GC_ARENA_SHIFT))), \
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ARENA_START_TO_INFO((arenaPage) << GC_ARENA_SHIFT))
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#define ARENA_INFO_TO_PAGE(arena) \
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(JS_ASSERT(IS_ARENA_INFO_ADDRESS(arena)), \
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((jsuword) (arena) >> GC_ARENA_SHIFT))
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#define GET_ARENA_INFO(chunk, index) \
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(JS_ASSERT((index) < GC_ARENAS_PER_CHUNK), \
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ARENA_START_TO_INFO(chunk + ((index) << GC_ARENA_SHIFT)))
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/*
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* Definitions for allocating arenas in chunks.
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*
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* All chunks that have at least one free arena are put on the doubly-linked
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* list with the head stored in JSRuntime.gcChunkList. JSGCChunkInfo contains
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* the head of the chunk's free arena list together with the link fields for
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* gcChunkList.
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*
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* Structure stored in one of chunk's free arenas. GET_CHUNK_INFO_INDEX gives
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* the index of this arena. When all arenas in the chunk are used, it is
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* removed from the list and the index is set to NO_FREE_ARENAS indicating
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* that the chunk is not on gcChunkList and has no JSGCChunkInfo available.
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*/
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struct JSGCChunkInfo {
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JSGCChunkInfo **prevp;
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JSGCChunkInfo *next;
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JSGCArenaInfo *lastFreeArena;
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uint32 numFreeArenas;
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};
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#define NO_FREE_ARENAS JS_BITMASK(GC_ARENA_SHIFT - 1)
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JS_STATIC_ASSERT(1 <= GC_ARENAS_PER_CHUNK &&
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GC_ARENAS_PER_CHUNK <= NO_FREE_ARENAS);
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#define GET_ARENA_CHUNK(arena, index) \
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(JS_ASSERT(GET_ARENA_INDEX(arena) == index), \
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ARENA_INFO_TO_START(arena) - ((index) << GC_ARENA_SHIFT))
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#define GET_ARENA_INDEX(arena) \
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((arena)->firstArena ? 0 : (uint32) (arena)->arenaIndex)
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#define GET_CHUNK_INFO_INDEX(chunk) \
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((uint32) ARENA_START_TO_INFO(chunk)->arenaIndex)
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#define SET_CHUNK_INFO_INDEX(chunk, index) \
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(JS_ASSERT((index) < GC_ARENAS_PER_CHUNK || (index) == NO_FREE_ARENAS), \
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(void) (ARENA_START_TO_INFO(chunk)->arenaIndex = (jsuword) (index)))
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#define GET_CHUNK_INFO(chunk, infoIndex) \
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(JS_ASSERT(GET_CHUNK_INFO_INDEX(chunk) == (infoIndex)), \
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JS_ASSERT((uint32) (infoIndex) < GC_ARENAS_PER_CHUNK), \
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(JSGCChunkInfo *) ((chunk) + ((infoIndex) << GC_ARENA_SHIFT)))
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#define CHUNK_INFO_TO_INDEX(ci) \
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GET_ARENA_INDEX(ARENA_START_TO_INFO((jsuword)ci))
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/*
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* Macros for GC-thing operations.
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*/
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#define THINGS_PER_ARENA(thingSize) \
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((GC_ARENA_SIZE - (uint32) sizeof(JSGCArenaInfo)) / ((thingSize) + 1U))
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#define THING_TO_ARENA(thing) \
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(JS_ASSERT(!JSString::isStatic(thing)), \
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(JSGCArenaInfo *)(((jsuword) (thing) | GC_ARENA_MASK) \
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+ 1 - sizeof(JSGCArenaInfo)))
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#define THING_TO_INDEX(thing, thingSize) \
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((uint32) ((jsuword) (thing) & GC_ARENA_MASK) / (uint32) (thingSize))
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#define THING_FLAGP(arena, thingIndex) \
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(JS_ASSERT((jsuword) (thingIndex) \
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< (jsuword) THINGS_PER_ARENA((arena)->list->thingSize)), \
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(uint8 *)(arena) - 1 - (thingIndex))
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#define THING_TO_FLAGP(thing, thingSize) \
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THING_FLAGP(THING_TO_ARENA(thing), THING_TO_INDEX(thing, thingSize))
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#define FLAGP_TO_ARENA(flagp) THING_TO_ARENA(flagp)
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#define FLAGP_TO_INDEX(flagp) \
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(JS_ASSERT(((jsuword) (flagp) & GC_ARENA_MASK) < ARENA_INFO_OFFSET), \
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(ARENA_INFO_OFFSET - 1 - (uint32) ((jsuword) (flagp) & GC_ARENA_MASK)))
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#define FLAGP_TO_THING(flagp, thingSize) \
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(JS_ASSERT(((jsuword) (flagp) & GC_ARENA_MASK) >= \
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(ARENA_INFO_OFFSET - THINGS_PER_ARENA(thingSize))), \
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(JSGCThing *)(((jsuword) (flagp) & ~GC_ARENA_MASK) + \
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(thingSize) * FLAGP_TO_INDEX(flagp)))
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static inline JSGCThing *
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NextThing(JSGCThing *thing, size_t thingSize)
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{
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return reinterpret_cast<JSGCThing *>(reinterpret_cast<jsuword>(thing) +
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thingSize);
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}
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static inline JSGCThing *
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MakeNewArenaFreeList(JSGCArenaInfo *a, unsigned thingSize, size_t nthings)
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{
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JS_ASSERT(nthings * thingSize < GC_ARENA_SIZE - sizeof(JSGCArenaInfo));
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jsuword thingsStart = ARENA_INFO_TO_START(a);
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JSGCThing *first = reinterpret_cast<JSGCThing *>(thingsStart);
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JSGCThing *last = reinterpret_cast<JSGCThing *>(thingsStart +
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(nthings - 1) * thingSize);
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for (JSGCThing *thing = first; thing != last;) {
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JSGCThing *next = NextThing(thing, thingSize);
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thing->link = next;
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thing = next;
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}
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last->link = NULL;
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return first;
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}
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/*
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* Macros for the specialized arena for doubles.
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*
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* DOUBLES_PER_ARENA defines the maximum number of doubles that the arena can
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* hold. We find it as the following. Let n be the number of doubles in the
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* arena. Together with the bitmap of flags and JSGCArenaInfo they should fit
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* the arena. Hence DOUBLES_PER_ARENA or n_max is the maximum value of n for
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* which the following holds:
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*
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* n*s + ceil(n/B) <= M (1)
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*
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* where "/" denotes normal real division,
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* ceil(r) gives the least integer not smaller than the number r,
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* s is the number of words in jsdouble,
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* B is number of bits per word or B == JS_BITS_PER_WORD
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* M is the number of words in the arena before JSGCArenaInfo or
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* M == (GC_ARENA_SIZE - sizeof(JSGCArenaInfo)) / sizeof(jsuword).
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* M == ARENA_INFO_OFFSET / sizeof(jsuword)
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*
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|
* We rewrite the inequality as
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|
*
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* n*B*s/B + ceil(n/B) <= M,
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* ceil(n*B*s/B + n/B) <= M,
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* ceil(n*(B*s + 1)/B) <= M (2)
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*
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|
* We define a helper function e(n, s, B),
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*
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* e(n, s, B) := ceil(n*(B*s + 1)/B) - n*(B*s + 1)/B, 0 <= e(n, s, B) < 1.
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*
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* It gives:
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*
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* n*(B*s + 1)/B + e(n, s, B) <= M,
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* n + e*B/(B*s + 1) <= M*B/(B*s + 1)
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*
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* We apply the floor function to both sides of the last equation, where
|
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* floor(r) gives the biggest integer not greater than r. As a consequence we
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* have:
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*
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* floor(n + e*B/(B*s + 1)) <= floor(M*B/(B*s + 1)),
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* n + floor(e*B/(B*s + 1)) <= floor(M*B/(B*s + 1)),
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* n <= floor(M*B/(B*s + 1)), (3)
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*
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* where floor(e*B/(B*s + 1)) is zero as e*B/(B*s + 1) < B/(B*s + 1) < 1.
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* Thus any n that satisfies the original constraint (1) or its equivalent (2),
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* must also satisfy (3). That is, we got an upper estimate for the maximum
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* value of n. Lets show that this upper estimate,
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*
|
|
* floor(M*B/(B*s + 1)), (4)
|
|
*
|
|
* also satisfies (1) and, as such, gives the required maximum value.
|
|
* Substituting it into (2) gives:
|
|
*
|
|
* ceil(floor(M*B/(B*s + 1))*(B*s + 1)/B) == ceil(floor(M/X)*X)
|
|
*
|
|
* where X == (B*s + 1)/B > 1. But then floor(M/X)*X <= M/X*X == M and
|
|
*
|
|
* ceil(floor(M/X)*X) <= ceil(M) == M.
|
|
*
|
|
* Thus the value of (4) gives the maximum n satisfying (1).
|
|
*
|
|
* For the final result we observe that in (4)
|
|
*
|
|
* M*B == ARENA_INFO_OFFSET / sizeof(jsuword) * JS_BITS_PER_WORD
|
|
* == ARENA_INFO_OFFSET * JS_BITS_PER_BYTE
|
|
*
|
|
* and
|
|
*
|
|
* B*s == JS_BITS_PER_WORD * sizeof(jsdouble) / sizeof(jsuword)
|
|
* == JS_BITS_PER_DOUBLE.
|
|
*/
|
|
const size_t DOUBLES_PER_ARENA =
|
|
(ARENA_INFO_OFFSET * JS_BITS_PER_BYTE) / (JS_BITS_PER_DOUBLE + 1);
|
|
|
|
/*
|
|
* Check that ARENA_INFO_OFFSET and sizeof(jsdouble) divides sizeof(jsuword).
|
|
*/
|
|
JS_STATIC_ASSERT(ARENA_INFO_OFFSET % sizeof(jsuword) == 0);
|
|
JS_STATIC_ASSERT(sizeof(jsdouble) % sizeof(jsuword) == 0);
|
|
JS_STATIC_ASSERT(sizeof(jsbitmap) == sizeof(jsuword));
|
|
|
|
const size_t DOUBLES_ARENA_BITMAP_WORDS =
|
|
JS_HOWMANY(DOUBLES_PER_ARENA, JS_BITS_PER_WORD);
|
|
|
|
/* Check that DOUBLES_PER_ARENA indeed maximises (1). */
|
|
JS_STATIC_ASSERT(DOUBLES_PER_ARENA * sizeof(jsdouble) +
|
|
DOUBLES_ARENA_BITMAP_WORDS * sizeof(jsuword) <=
|
|
ARENA_INFO_OFFSET);
|
|
|
|
JS_STATIC_ASSERT((DOUBLES_PER_ARENA + 1) * sizeof(jsdouble) +
|
|
sizeof(jsuword) *
|
|
JS_HOWMANY((DOUBLES_PER_ARENA + 1), JS_BITS_PER_WORD) >
|
|
ARENA_INFO_OFFSET);
|
|
|
|
/*
|
|
* When DOUBLES_PER_ARENA % BITS_PER_DOUBLE_FLAG_UNIT != 0, some bits in the
|
|
* last byte of the occupation bitmap are unused.
|
|
*/
|
|
const size_t UNUSED_DOUBLE_BITMAP_BITS =
|
|
DOUBLES_ARENA_BITMAP_WORDS * JS_BITS_PER_WORD - DOUBLES_PER_ARENA;
|
|
|
|
JS_STATIC_ASSERT(UNUSED_DOUBLE_BITMAP_BITS < JS_BITS_PER_WORD);
|
|
|
|
const size_t DOUBLES_ARENA_BITMAP_OFFSET =
|
|
ARENA_INFO_OFFSET - DOUBLES_ARENA_BITMAP_WORDS * sizeof(jsuword);
|
|
|
|
#define CHECK_DOUBLE_ARENA_INFO(arenaInfo) \
|
|
(JS_ASSERT(IS_ARENA_INFO_ADDRESS(arenaInfo)), \
|
|
JS_ASSERT(!(arenaInfo)->list)) \
|
|
|
|
/*
|
|
* Get the start of the bitmap area containing double mark flags in the arena.
|
|
* To access the flag the code uses
|
|
*
|
|
* JS_TEST_BIT(bitmapStart, index)
|
|
*
|
|
* That is, compared with the case of arenas with non-double things, we count
|
|
* flags from the start of the bitmap area, not from the end.
|
|
*/
|
|
#define DOUBLE_ARENA_BITMAP(arenaInfo) \
|
|
(CHECK_DOUBLE_ARENA_INFO(arenaInfo), \
|
|
(jsbitmap *) arenaInfo - DOUBLES_ARENA_BITMAP_WORDS)
|
|
|
|
#define DOUBLE_ARENA_BITMAP_END(arenaInfo) \
|
|
(CHECK_DOUBLE_ARENA_INFO(arenaInfo), (jsbitmap *) (arenaInfo))
|
|
|
|
#define DOUBLE_THING_TO_INDEX(thing) \
|
|
(CHECK_DOUBLE_ARENA_INFO(THING_TO_ARENA(thing)), \
|
|
JS_ASSERT(((jsuword) (thing) & GC_ARENA_MASK) < \
|
|
DOUBLES_ARENA_BITMAP_OFFSET), \
|
|
((uint32) (((jsuword) (thing) & GC_ARENA_MASK) / sizeof(jsdouble))))
|
|
|
|
static void
|
|
ClearDoubleArenaFlags(JSGCArenaInfo *a)
|
|
{
|
|
/*
|
|
* When some high bits in the last byte of the double occupation bitmap
|
|
* are unused, we must set them. Otherwise TurnUsedArenaIntoDoubleList
|
|
* will assume that they corresponds to some free cells and tries to
|
|
* allocate them.
|
|
*
|
|
* Note that the code works correctly with UNUSED_DOUBLE_BITMAP_BITS == 0.
|
|
*/
|
|
jsbitmap *bitmap = DOUBLE_ARENA_BITMAP(a);
|
|
memset(bitmap, 0, (DOUBLES_ARENA_BITMAP_WORDS - 1) * sizeof *bitmap);
|
|
jsbitmap mask = ((jsbitmap) 1 << UNUSED_DOUBLE_BITMAP_BITS) - 1;
|
|
size_t nused = JS_BITS_PER_WORD - UNUSED_DOUBLE_BITMAP_BITS;
|
|
bitmap[DOUBLES_ARENA_BITMAP_WORDS - 1] = mask << nused;
|
|
}
|
|
|
|
static JS_ALWAYS_INLINE JSBool
|
|
IsMarkedDouble(JSGCArenaInfo *a, uint32 index)
|
|
{
|
|
jsbitmap *bitmap;
|
|
|
|
JS_ASSERT(a->hasMarkedDoubles);
|
|
bitmap = DOUBLE_ARENA_BITMAP(a);
|
|
return JS_TEST_BIT(bitmap, index);
|
|
}
|
|
|
|
JS_STATIC_ASSERT(sizeof(JSStackHeader) >= 2 * sizeof(jsval));
|
|
|
|
JS_STATIC_ASSERT(sizeof(JSGCThing) <= sizeof(JSString));
|
|
JS_STATIC_ASSERT(sizeof(JSGCThing) <= sizeof(jsdouble));
|
|
|
|
/* We want to use all the available GC thing space for object's slots. */
|
|
JS_STATIC_ASSERT(sizeof(JSObject) % sizeof(JSGCThing) == 0);
|
|
|
|
#ifdef JS_GCMETER
|
|
# define METER(x) ((void) (x))
|
|
# define METER_IF(condition, x) ((void) ((condition) && (x)))
|
|
#else
|
|
# define METER(x) ((void) 0)
|
|
# define METER_IF(condition, x) ((void) 0)
|
|
#endif
|
|
|
|
#define METER_UPDATE_MAX(maxLval, rval) \
|
|
METER_IF((maxLval) < (rval), (maxLval) = (rval))
|
|
|
|
static jsuword
|
|
NewGCChunk(void)
|
|
{
|
|
void *p;
|
|
|
|
#if defined(XP_WIN)
|
|
p = VirtualAlloc(NULL, GC_ARENAS_PER_CHUNK << GC_ARENA_SHIFT,
|
|
MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
|
|
return (jsuword) p;
|
|
#elif defined(XP_OS2)
|
|
if (DosAllocMem(&p, GC_ARENAS_PER_CHUNK << GC_ARENA_SHIFT,
|
|
OBJ_ANY | PAG_COMMIT | PAG_READ | PAG_WRITE)) {
|
|
if (DosAllocMem(&p, GC_ARENAS_PER_CHUNK << GC_ARENA_SHIFT,
|
|
PAG_COMMIT | PAG_READ | PAG_WRITE)) {
|
|
return 0;
|
|
}
|
|
}
|
|
return (jsuword) p;
|
|
#else
|
|
p = mmap(NULL, GC_ARENAS_PER_CHUNK << GC_ARENA_SHIFT,
|
|
PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
|
|
return (p == MAP_FAILED) ? 0 : (jsuword) p;
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
DestroyGCChunk(jsuword chunk)
|
|
{
|
|
JS_ASSERT((chunk & GC_ARENA_MASK) == 0);
|
|
#if defined(XP_WIN)
|
|
VirtualFree((void *) chunk, 0, MEM_RELEASE);
|
|
#elif defined(XP_OS2)
|
|
DosFreeMem((void *) chunk);
|
|
#elif defined(SOLARIS)
|
|
munmap((char *) chunk, GC_ARENAS_PER_CHUNK << GC_ARENA_SHIFT);
|
|
#else
|
|
munmap((void *) chunk, GC_ARENAS_PER_CHUNK << GC_ARENA_SHIFT);
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
AddChunkToList(JSRuntime *rt, JSGCChunkInfo *ci)
|
|
{
|
|
ci->prevp = &rt->gcChunkList;
|
|
ci->next = rt->gcChunkList;
|
|
if (rt->gcChunkList) {
|
|
JS_ASSERT(rt->gcChunkList->prevp == &rt->gcChunkList);
|
|
rt->gcChunkList->prevp = &ci->next;
|
|
}
|
|
rt->gcChunkList = ci;
|
|
}
|
|
|
|
static void
|
|
RemoveChunkFromList(JSRuntime *rt, JSGCChunkInfo *ci)
|
|
{
|
|
*ci->prevp = ci->next;
|
|
if (ci->next) {
|
|
JS_ASSERT(ci->next->prevp == &ci->next);
|
|
ci->next->prevp = ci->prevp;
|
|
}
|
|
}
|
|
|
|
static JSGCArenaInfo *
|
|
NewGCArena(JSContext *cx)
|
|
{
|
|
jsuword chunk;
|
|
JSGCArenaInfo *a;
|
|
|
|
JSRuntime *rt = cx->runtime;
|
|
if (!JS_THREAD_DATA(cx)->waiveGCQuota && rt->gcBytes >= rt->gcMaxBytes) {
|
|
/*
|
|
* FIXME bug 524051 We cannot run a last-ditch GC on trace for now, so
|
|
* just pretend we are out of memory which will throw us off trace and
|
|
* we will re-try this code path from the interpreter.
|
|
*/
|
|
if (!JS_ON_TRACE(cx))
|
|
return NULL;
|
|
js_TriggerGC(cx, true);
|
|
}
|
|
|
|
JSGCChunkInfo *ci;
|
|
uint32 i;
|
|
JSGCArenaInfo *aprev;
|
|
|
|
ci = rt->gcChunkList;
|
|
if (!ci) {
|
|
chunk = NewGCChunk();
|
|
if (chunk == 0)
|
|
return NULL;
|
|
JS_ASSERT((chunk & GC_ARENA_MASK) == 0);
|
|
a = GET_ARENA_INFO(chunk, 0);
|
|
a->firstArena = JS_TRUE;
|
|
a->arenaIndex = 0;
|
|
aprev = NULL;
|
|
i = 0;
|
|
do {
|
|
a->prev = aprev;
|
|
aprev = a;
|
|
++i;
|
|
a = GET_ARENA_INFO(chunk, i);
|
|
a->firstArena = JS_FALSE;
|
|
a->arenaIndex = i;
|
|
} while (i != GC_ARENAS_PER_CHUNK - 1);
|
|
ci = GET_CHUNK_INFO(chunk, 0);
|
|
ci->lastFreeArena = aprev;
|
|
ci->numFreeArenas = GC_ARENAS_PER_CHUNK - 1;
|
|
AddChunkToList(rt, ci);
|
|
} else {
|
|
JS_ASSERT(ci->prevp == &rt->gcChunkList);
|
|
a = ci->lastFreeArena;
|
|
aprev = a->prev;
|
|
if (!aprev) {
|
|
JS_ASSERT(ci->numFreeArenas == 1);
|
|
JS_ASSERT(ARENA_INFO_TO_START(a) == (jsuword) ci);
|
|
RemoveChunkFromList(rt, ci);
|
|
chunk = GET_ARENA_CHUNK(a, GET_ARENA_INDEX(a));
|
|
SET_CHUNK_INFO_INDEX(chunk, NO_FREE_ARENAS);
|
|
} else {
|
|
JS_ASSERT(ci->numFreeArenas >= 2);
|
|
JS_ASSERT(ARENA_INFO_TO_START(a) != (jsuword) ci);
|
|
ci->lastFreeArena = aprev;
|
|
ci->numFreeArenas--;
|
|
}
|
|
}
|
|
|
|
rt->gcBytes += GC_ARENA_SIZE;
|
|
a->prevUnmarkedPage = 0;
|
|
|
|
return a;
|
|
}
|
|
|
|
static void
|
|
DestroyGCArenas(JSRuntime *rt, JSGCArenaInfo *last)
|
|
{
|
|
JSGCArenaInfo *a;
|
|
|
|
while (last) {
|
|
a = last;
|
|
last = last->prev;
|
|
|
|
METER(rt->gcStats.afree++);
|
|
JS_ASSERT(rt->gcBytes >= GC_ARENA_SIZE);
|
|
rt->gcBytes -= GC_ARENA_SIZE;
|
|
|
|
uint32 arenaIndex;
|
|
jsuword chunk;
|
|
uint32 chunkInfoIndex;
|
|
JSGCChunkInfo *ci;
|
|
#ifdef DEBUG
|
|
jsuword firstArena;
|
|
|
|
firstArena = a->firstArena;
|
|
arenaIndex = a->arenaIndex;
|
|
memset((void *) ARENA_INFO_TO_START(a), JS_FREE_PATTERN, GC_ARENA_SIZE);
|
|
a->firstArena = firstArena;
|
|
a->arenaIndex = arenaIndex;
|
|
#endif
|
|
arenaIndex = GET_ARENA_INDEX(a);
|
|
chunk = GET_ARENA_CHUNK(a, arenaIndex);
|
|
chunkInfoIndex = GET_CHUNK_INFO_INDEX(chunk);
|
|
if (chunkInfoIndex == NO_FREE_ARENAS) {
|
|
chunkInfoIndex = arenaIndex;
|
|
SET_CHUNK_INFO_INDEX(chunk, arenaIndex);
|
|
ci = GET_CHUNK_INFO(chunk, chunkInfoIndex);
|
|
a->prev = NULL;
|
|
ci->lastFreeArena = a;
|
|
ci->numFreeArenas = 1;
|
|
AddChunkToList(rt, ci);
|
|
} else {
|
|
JS_ASSERT(chunkInfoIndex != arenaIndex);
|
|
ci = GET_CHUNK_INFO(chunk, chunkInfoIndex);
|
|
JS_ASSERT(ci->numFreeArenas != 0);
|
|
JS_ASSERT(ci->lastFreeArena);
|
|
JS_ASSERT(a != ci->lastFreeArena);
|
|
if (ci->numFreeArenas == GC_ARENAS_PER_CHUNK - 1) {
|
|
RemoveChunkFromList(rt, ci);
|
|
DestroyGCChunk(chunk);
|
|
} else {
|
|
++ci->numFreeArenas;
|
|
a->prev = ci->lastFreeArena;
|
|
ci->lastFreeArena = a;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static inline size_t
|
|
GetFinalizableThingSize(unsigned thingKind)
|
|
{
|
|
JS_STATIC_ASSERT(JS_EXTERNAL_STRING_LIMIT == 8);
|
|
|
|
static const uint8 map[FINALIZE_LIMIT] = {
|
|
sizeof(JSObject), /* FINALIZE_OBJECT */
|
|
sizeof(JSFunction), /* FINALIZE_FUNCTION */
|
|
#if JS_HAS_XML_SUPPORT
|
|
sizeof(JSXML), /* FINALIZE_XML */
|
|
#endif
|
|
sizeof(JSString), /* FINALIZE_STRING */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING0 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING1 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING2 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING3 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING4 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING5 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING6 */
|
|
sizeof(JSString), /* FINALIZE_EXTERNAL_STRING7 */
|
|
};
|
|
|
|
JS_ASSERT(thingKind < FINALIZE_LIMIT);
|
|
return map[thingKind];
|
|
}
|
|
|
|
static inline size_t
|
|
GetFinalizableTraceKind(size_t thingKind)
|
|
{
|
|
JS_STATIC_ASSERT(JS_EXTERNAL_STRING_LIMIT == 8);
|
|
|
|
static const uint8 map[FINALIZE_LIMIT] = {
|
|
JSTRACE_OBJECT, /* FINALIZE_OBJECT */
|
|
JSTRACE_OBJECT, /* FINALIZE_FUNCTION */
|
|
#if JS_HAS_XML_SUPPORT /* FINALIZE_XML */
|
|
JSTRACE_XML,
|
|
#endif /* FINALIZE_STRING */
|
|
JSTRACE_STRING,
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING0 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING1 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING2 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING3 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING4 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING5 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING6 */
|
|
JSTRACE_STRING, /* FINALIZE_EXTERNAL_STRING7 */
|
|
};
|
|
|
|
JS_ASSERT(thingKind < FINALIZE_LIMIT);
|
|
return map[thingKind];
|
|
}
|
|
|
|
static inline size_t
|
|
GetFinalizableArenaTraceKind(JSGCArenaInfo *a)
|
|
{
|
|
JS_ASSERT(a->list);
|
|
return GetFinalizableTraceKind(a->list->thingKind);
|
|
}
|
|
|
|
static void
|
|
InitGCArenaLists(JSRuntime *rt)
|
|
{
|
|
for (unsigned i = 0; i != FINALIZE_LIMIT; ++i) {
|
|
JSGCArenaList *arenaList = &rt->gcArenaList[i];
|
|
arenaList->head = NULL;
|
|
arenaList->cursor = NULL;
|
|
arenaList->thingKind = i;
|
|
arenaList->thingSize = GetFinalizableThingSize(i);
|
|
}
|
|
rt->gcDoubleArenaList.head = NULL;
|
|
rt->gcDoubleArenaList.cursor = NULL;
|
|
}
|
|
|
|
static void
|
|
FinishGCArenaLists(JSRuntime *rt)
|
|
{
|
|
for (unsigned i = 0; i < FINALIZE_LIMIT; i++) {
|
|
JSGCArenaList *arenaList = &rt->gcArenaList[i];
|
|
DestroyGCArenas(rt, arenaList->head);
|
|
arenaList->head = NULL;
|
|
arenaList->cursor = NULL;
|
|
}
|
|
DestroyGCArenas(rt, rt->gcDoubleArenaList.head);
|
|
rt->gcDoubleArenaList.head = NULL;
|
|
rt->gcDoubleArenaList.cursor = NULL;
|
|
|
|
rt->gcBytes = 0;
|
|
JS_ASSERT(rt->gcChunkList == 0);
|
|
}
|
|
|
|
/*
|
|
* This function must not be called when thing is jsdouble.
|
|
*/
|
|
static uint8 *
|
|
GetGCThingFlags(void *thing)
|
|
{
|
|
JSGCArenaInfo *a;
|
|
uint32 index;
|
|
|
|
a = THING_TO_ARENA(thing);
|
|
index = THING_TO_INDEX(thing, a->list->thingSize);
|
|
return THING_FLAGP(a, index);
|
|
}
|
|
|
|
intN
|
|
js_GetExternalStringGCType(JSString *str)
|
|
{
|
|
JS_STATIC_ASSERT(FINALIZE_STRING + 1 == FINALIZE_EXTERNAL_STRING0);
|
|
JS_ASSERT(!JSString::isStatic(str));
|
|
|
|
unsigned thingKind = THING_TO_ARENA(str)->list->thingKind;
|
|
JS_ASSERT(IsFinalizableStringKind(thingKind));
|
|
return intN(thingKind) - intN(FINALIZE_EXTERNAL_STRING0);
|
|
}
|
|
|
|
JS_FRIEND_API(uint32)
|
|
js_GetGCThingTraceKind(void *thing)
|
|
{
|
|
if (JSString::isStatic(thing))
|
|
return JSTRACE_STRING;
|
|
|
|
JSGCArenaInfo *a = THING_TO_ARENA(thing);
|
|
if (!a->list)
|
|
return JSTRACE_DOUBLE;
|
|
return GetFinalizableArenaTraceKind(a);
|
|
}
|
|
|
|
JSRuntime*
|
|
js_GetGCStringRuntime(JSString *str)
|
|
{
|
|
JSGCArenaList *list = THING_TO_ARENA(str)->list;
|
|
JS_ASSERT(list->thingSize == sizeof(JSString));
|
|
|
|
unsigned i = list->thingKind;
|
|
JS_ASSERT(i == FINALIZE_STRING ||
|
|
(FINALIZE_EXTERNAL_STRING0 <= i &&
|
|
i < FINALIZE_EXTERNAL_STRING0 + JS_EXTERNAL_STRING_LIMIT));
|
|
return (JSRuntime *)((uint8 *)(list - i) -
|
|
offsetof(JSRuntime, gcArenaList));
|
|
}
|
|
|
|
bool
|
|
js_IsAboutToBeFinalized(void *thing)
|
|
{
|
|
JSGCArenaInfo *a;
|
|
uint32 index, flags;
|
|
|
|
if (JSString::isStatic(thing))
|
|
return false;
|
|
|
|
a = THING_TO_ARENA(thing);
|
|
if (!a->list) {
|
|
/*
|
|
* Check if arena has no marked doubles. In that case the bitmap with
|
|
* the mark flags contains all garbage as it is initialized only when
|
|
* marking the first double in the arena.
|
|
*/
|
|
if (!a->hasMarkedDoubles)
|
|
return JS_TRUE;
|
|
index = DOUBLE_THING_TO_INDEX(thing);
|
|
return !IsMarkedDouble(a, index);
|
|
}
|
|
index = THING_TO_INDEX(thing, a->list->thingSize);
|
|
flags = *THING_FLAGP(a, index);
|
|
return !(flags & (GCF_MARK | GCF_LOCK));
|
|
}
|
|
|
|
/* This is compatible with JSDHashEntryStub. */
|
|
typedef struct JSGCRootHashEntry {
|
|
JSDHashEntryHdr hdr;
|
|
void *root;
|
|
const char *name;
|
|
} JSGCRootHashEntry;
|
|
|
|
/* Initial size of the gcRootsHash table (SWAG, small enough to amortize). */
|
|
#define GC_ROOTS_SIZE 256
|
|
|
|
/*
|
|
* For a CPU with extremely large pages using them for GC things wastes
|
|
* too much memory.
|
|
*/
|
|
#define GC_ARENAS_PER_CPU_PAGE_LIMIT JS_BIT(18 - GC_ARENA_SHIFT)
|
|
|
|
JS_STATIC_ASSERT(GC_ARENAS_PER_CPU_PAGE_LIMIT <= NO_FREE_ARENAS);
|
|
|
|
JSBool
|
|
js_InitGC(JSRuntime *rt, uint32 maxbytes)
|
|
{
|
|
InitGCArenaLists(rt);
|
|
if (!JS_DHashTableInit(&rt->gcRootsHash, JS_DHashGetStubOps(), NULL,
|
|
sizeof(JSGCRootHashEntry), GC_ROOTS_SIZE)) {
|
|
rt->gcRootsHash.ops = NULL;
|
|
return JS_FALSE;
|
|
}
|
|
rt->gcLocksHash = NULL; /* create lazily */
|
|
|
|
/*
|
|
* Separate gcMaxMallocBytes from gcMaxBytes but initialize to maxbytes
|
|
* for default backward API compatibility.
|
|
*/
|
|
rt->gcMaxBytes = maxbytes;
|
|
rt->setGCMaxMallocBytes(maxbytes);
|
|
|
|
rt->gcEmptyArenaPoolLifespan = 30000;
|
|
|
|
/*
|
|
* By default the trigger factor gets maximum possible value. This
|
|
* means that GC will not be triggered by growth of GC memory (gcBytes).
|
|
*/
|
|
rt->setGCTriggerFactor((uint32) -1);
|
|
|
|
/*
|
|
* The assigned value prevents GC from running when GC memory is too low
|
|
* (during JS engine start).
|
|
*/
|
|
rt->setGCLastBytes(8192);
|
|
|
|
METER(memset(&rt->gcStats, 0, sizeof rt->gcStats));
|
|
return JS_TRUE;
|
|
}
|
|
|
|
#ifdef JS_GCMETER
|
|
|
|
static void
|
|
UpdateArenaStats(JSGCArenaStats *st, uint32 nlivearenas, uint32 nkilledArenas,
|
|
uint32 nthings)
|
|
{
|
|
size_t narenas;
|
|
|
|
narenas = nlivearenas + nkilledArenas;
|
|
JS_ASSERT(narenas >= st->livearenas);
|
|
|
|
st->newarenas = narenas - st->livearenas;
|
|
st->narenas = narenas;
|
|
st->livearenas = nlivearenas;
|
|
if (st->maxarenas < narenas)
|
|
st->maxarenas = narenas;
|
|
st->totalarenas += narenas;
|
|
|
|
st->nthings = nthings;
|
|
if (st->maxthings < nthings)
|
|
st->maxthings = nthings;
|
|
st->totalthings += nthings;
|
|
}
|
|
|
|
JS_FRIEND_API(void)
|
|
js_DumpGCStats(JSRuntime *rt, FILE *fp)
|
|
{
|
|
int i;
|
|
size_t sumArenas, sumTotalArenas;
|
|
size_t sumThings, sumMaxThings;
|
|
size_t sumThingSize, sumTotalThingSize;
|
|
size_t sumArenaCapacity, sumTotalArenaCapacity;
|
|
JSGCArenaStats *st;
|
|
size_t thingSize, thingsPerArena;
|
|
size_t sumAlloc, sumLocalAlloc, sumFail, sumRetry;
|
|
|
|
fprintf(fp, "\nGC allocation statistics:\n");
|
|
|
|
#define UL(x) ((unsigned long)(x))
|
|
#define ULSTAT(x) UL(rt->gcStats.x)
|
|
#define PERCENT(x,y) (100.0 * (double) (x) / (double) (y))
|
|
|
|
sumArenas = 0;
|
|
sumTotalArenas = 0;
|
|
sumThings = 0;
|
|
sumMaxThings = 0;
|
|
sumThingSize = 0;
|
|
sumTotalThingSize = 0;
|
|
sumArenaCapacity = 0;
|
|
sumTotalArenaCapacity = 0;
|
|
sumAlloc = 0;
|
|
sumLocalAlloc = 0;
|
|
sumFail = 0;
|
|
sumRetry = 0;
|
|
for (i = -1; i < (int) GC_NUM_FREELISTS; i++) {
|
|
if (i == -1) {
|
|
thingSize = sizeof(jsdouble);
|
|
thingsPerArena = DOUBLES_PER_ARENA;
|
|
st = &rt->gcStats.doubleArenaStats;
|
|
fprintf(fp,
|
|
"Arena list for double values (%lu doubles per arena):",
|
|
UL(thingsPerArena));
|
|
} else {
|
|
thingSize = rt->gcArenaList[i].thingSize;
|
|
thingsPerArena = THINGS_PER_ARENA(thingSize);
|
|
st = &rt->gcStats.arenaStats[i];
|
|
fprintf(fp,
|
|
"Arena list %d (thing size %lu, %lu things per arena):",
|
|
i, UL(GC_FREELIST_NBYTES(i)), UL(thingsPerArena));
|
|
}
|
|
if (st->maxarenas == 0) {
|
|
fputs(" NEVER USED\n", fp);
|
|
continue;
|
|
}
|
|
putc('\n', fp);
|
|
fprintf(fp, " arenas before GC: %lu\n", UL(st->narenas));
|
|
fprintf(fp, " new arenas before GC: %lu (%.1f%%)\n",
|
|
UL(st->newarenas), PERCENT(st->newarenas, st->narenas));
|
|
fprintf(fp, " arenas after GC: %lu (%.1f%%)\n",
|
|
UL(st->livearenas), PERCENT(st->livearenas, st->narenas));
|
|
fprintf(fp, " max arenas: %lu\n", UL(st->maxarenas));
|
|
fprintf(fp, " things: %lu\n", UL(st->nthings));
|
|
fprintf(fp, " GC cell utilization: %.1f%%\n",
|
|
PERCENT(st->nthings, thingsPerArena * st->narenas));
|
|
fprintf(fp, " average cell utilization: %.1f%%\n",
|
|
PERCENT(st->totalthings, thingsPerArena * st->totalarenas));
|
|
fprintf(fp, " max things: %lu\n", UL(st->maxthings));
|
|
fprintf(fp, " alloc attempts: %lu\n", UL(st->alloc));
|
|
fprintf(fp, " alloc without locks: %1u (%.1f%%)\n",
|
|
UL(st->localalloc), PERCENT(st->localalloc, st->alloc));
|
|
sumArenas += st->narenas;
|
|
sumTotalArenas += st->totalarenas;
|
|
sumThings += st->nthings;
|
|
sumMaxThings += st->maxthings;
|
|
sumThingSize += thingSize * st->nthings;
|
|
sumTotalThingSize += thingSize * st->totalthings;
|
|
sumArenaCapacity += thingSize * thingsPerArena * st->narenas;
|
|
sumTotalArenaCapacity += thingSize * thingsPerArena * st->totalarenas;
|
|
sumAlloc += st->alloc;
|
|
sumLocalAlloc += st->localalloc;
|
|
sumFail += st->fail;
|
|
sumRetry += st->retry;
|
|
}
|
|
fprintf(fp, "TOTAL STATS:\n");
|
|
fprintf(fp, " bytes allocated: %lu\n", UL(rt->gcBytes));
|
|
fprintf(fp, " total GC arenas: %lu\n", UL(sumArenas));
|
|
fprintf(fp, " total GC things: %lu\n", UL(sumThings));
|
|
fprintf(fp, " max total GC things: %lu\n", UL(sumMaxThings));
|
|
fprintf(fp, " GC cell utilization: %.1f%%\n",
|
|
PERCENT(sumThingSize, sumArenaCapacity));
|
|
fprintf(fp, " average cell utilization: %.1f%%\n",
|
|
PERCENT(sumTotalThingSize, sumTotalArenaCapacity));
|
|
fprintf(fp, "allocation retries after GC: %lu\n", UL(sumRetry));
|
|
fprintf(fp, " alloc attempts: %lu\n", UL(sumAlloc));
|
|
fprintf(fp, " alloc without locks: %1u (%.1f%%)\n",
|
|
UL(sumLocalAlloc), PERCENT(sumLocalAlloc, sumAlloc));
|
|
fprintf(fp, " allocation failures: %lu\n", UL(sumFail));
|
|
fprintf(fp, " things born locked: %lu\n", ULSTAT(lockborn));
|
|
fprintf(fp, " valid lock calls: %lu\n", ULSTAT(lock));
|
|
fprintf(fp, " valid unlock calls: %lu\n", ULSTAT(unlock));
|
|
fprintf(fp, " mark recursion depth: %lu\n", ULSTAT(depth));
|
|
fprintf(fp, " maximum mark recursion: %lu\n", ULSTAT(maxdepth));
|
|
fprintf(fp, " mark C recursion depth: %lu\n", ULSTAT(cdepth));
|
|
fprintf(fp, " maximum mark C recursion: %lu\n", ULSTAT(maxcdepth));
|
|
fprintf(fp, " delayed tracing calls: %lu\n", ULSTAT(unmarked));
|
|
#ifdef DEBUG
|
|
fprintf(fp, " max trace later count: %lu\n", ULSTAT(maxunmarked));
|
|
#endif
|
|
fprintf(fp, " maximum GC nesting level: %lu\n", ULSTAT(maxlevel));
|
|
fprintf(fp, "potentially useful GC calls: %lu\n", ULSTAT(poke));
|
|
fprintf(fp, " thing arenas freed so far: %lu\n", ULSTAT(afree));
|
|
fprintf(fp, " stack segments scanned: %lu\n", ULSTAT(stackseg));
|
|
fprintf(fp, "stack segment slots scanned: %lu\n", ULSTAT(segslots));
|
|
fprintf(fp, "reachable closeable objects: %lu\n", ULSTAT(nclose));
|
|
fprintf(fp, " max reachable closeable: %lu\n", ULSTAT(maxnclose));
|
|
fprintf(fp, " scheduled close hooks: %lu\n", ULSTAT(closelater));
|
|
fprintf(fp, " max scheduled close hooks: %lu\n", ULSTAT(maxcloselater));
|
|
|
|
#undef UL
|
|
#undef ULSTAT
|
|
#undef PERCENT
|
|
|
|
#ifdef JS_ARENAMETER
|
|
JS_DumpArenaStats(fp);
|
|
#endif
|
|
}
|
|
#endif
|
|
|
|
#ifdef DEBUG
|
|
static void
|
|
CheckLeakedRoots(JSRuntime *rt);
|
|
#endif
|
|
|
|
void
|
|
js_FinishGC(JSRuntime *rt)
|
|
{
|
|
#ifdef JS_ARENAMETER
|
|
JS_DumpArenaStats(stdout);
|
|
#endif
|
|
#ifdef JS_GCMETER
|
|
js_DumpGCStats(rt, stdout);
|
|
#endif
|
|
|
|
rt->gcIteratorTable.clear();
|
|
FinishGCArenaLists(rt);
|
|
|
|
if (rt->gcRootsHash.ops) {
|
|
#ifdef DEBUG
|
|
CheckLeakedRoots(rt);
|
|
#endif
|
|
JS_DHashTableFinish(&rt->gcRootsHash);
|
|
rt->gcRootsHash.ops = NULL;
|
|
}
|
|
if (rt->gcLocksHash) {
|
|
JS_DHashTableDestroy(rt->gcLocksHash);
|
|
rt->gcLocksHash = NULL;
|
|
}
|
|
}
|
|
|
|
JSBool
|
|
js_AddRoot(JSContext *cx, void *rp, const char *name)
|
|
{
|
|
JSBool ok = js_AddRootRT(cx->runtime, rp, name);
|
|
if (!ok)
|
|
JS_ReportOutOfMemory(cx);
|
|
return ok;
|
|
}
|
|
|
|
JSBool
|
|
js_AddRootRT(JSRuntime *rt, void *rp, const char *name)
|
|
{
|
|
JSBool ok;
|
|
JSGCRootHashEntry *rhe;
|
|
|
|
/*
|
|
* Due to the long-standing, but now removed, use of rt->gcLock across the
|
|
* bulk of js_GC, API users have come to depend on JS_AddRoot etc. locking
|
|
* properly with a racing GC, without calling JS_AddRoot from a request.
|
|
* We have to preserve API compatibility here, now that we avoid holding
|
|
* rt->gcLock across the mark phase (including the root hashtable mark).
|
|
*/
|
|
JS_LOCK_GC(rt);
|
|
js_WaitForGC(rt);
|
|
rhe = (JSGCRootHashEntry *)
|
|
JS_DHashTableOperate(&rt->gcRootsHash, rp, JS_DHASH_ADD);
|
|
if (rhe) {
|
|
rhe->root = rp;
|
|
rhe->name = name;
|
|
ok = JS_TRUE;
|
|
} else {
|
|
ok = JS_FALSE;
|
|
}
|
|
JS_UNLOCK_GC(rt);
|
|
return ok;
|
|
}
|
|
|
|
JSBool
|
|
js_RemoveRoot(JSRuntime *rt, void *rp)
|
|
{
|
|
/*
|
|
* Due to the JS_RemoveRootRT API, we may be called outside of a request.
|
|
* Same synchronization drill as above in js_AddRoot.
|
|
*/
|
|
JS_LOCK_GC(rt);
|
|
js_WaitForGC(rt);
|
|
(void) JS_DHashTableOperate(&rt->gcRootsHash, rp, JS_DHASH_REMOVE);
|
|
rt->gcPoke = JS_TRUE;
|
|
JS_UNLOCK_GC(rt);
|
|
return JS_TRUE;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
|
|
static JSDHashOperator
|
|
js_root_printer(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 i, void *arg)
|
|
{
|
|
uint32 *leakedroots = (uint32 *)arg;
|
|
JSGCRootHashEntry *rhe = (JSGCRootHashEntry *)hdr;
|
|
|
|
(*leakedroots)++;
|
|
fprintf(stderr,
|
|
"JS engine warning: leaking GC root \'%s\' at %p\n",
|
|
rhe->name ? (char *)rhe->name : "", rhe->root);
|
|
|
|
return JS_DHASH_NEXT;
|
|
}
|
|
|
|
static void
|
|
CheckLeakedRoots(JSRuntime *rt)
|
|
{
|
|
uint32 leakedroots = 0;
|
|
|
|
/* Warn (but don't assert) debug builds of any remaining roots. */
|
|
JS_DHashTableEnumerate(&rt->gcRootsHash, js_root_printer,
|
|
&leakedroots);
|
|
if (leakedroots > 0) {
|
|
if (leakedroots == 1) {
|
|
fprintf(stderr,
|
|
"JS engine warning: 1 GC root remains after destroying the JSRuntime at %p.\n"
|
|
" This root may point to freed memory. Objects reachable\n"
|
|
" through it have not been finalized.\n",
|
|
(void *) rt);
|
|
} else {
|
|
fprintf(stderr,
|
|
"JS engine warning: %lu GC roots remain after destroying the JSRuntime at %p.\n"
|
|
" These roots may point to freed memory. Objects reachable\n"
|
|
" through them have not been finalized.\n",
|
|
(unsigned long) leakedroots, (void *) rt);
|
|
}
|
|
}
|
|
}
|
|
|
|
typedef struct NamedRootDumpArgs {
|
|
void (*dump)(const char *name, void *rp, void *data);
|
|
void *data;
|
|
} NamedRootDumpArgs;
|
|
|
|
static JSDHashOperator
|
|
js_named_root_dumper(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 number,
|
|
void *arg)
|
|
{
|
|
NamedRootDumpArgs *args = (NamedRootDumpArgs *) arg;
|
|
JSGCRootHashEntry *rhe = (JSGCRootHashEntry *)hdr;
|
|
|
|
if (rhe->name)
|
|
args->dump(rhe->name, rhe->root, args->data);
|
|
return JS_DHASH_NEXT;
|
|
}
|
|
|
|
JS_BEGIN_EXTERN_C
|
|
void
|
|
js_DumpNamedRoots(JSRuntime *rt,
|
|
void (*dump)(const char *name, void *rp, void *data),
|
|
void *data)
|
|
{
|
|
NamedRootDumpArgs args;
|
|
|
|
args.dump = dump;
|
|
args.data = data;
|
|
JS_DHashTableEnumerate(&rt->gcRootsHash, js_named_root_dumper, &args);
|
|
}
|
|
JS_END_EXTERN_C
|
|
|
|
#endif /* DEBUG */
|
|
|
|
typedef struct GCRootMapArgs {
|
|
JSGCRootMapFun map;
|
|
void *data;
|
|
} GCRootMapArgs;
|
|
|
|
static JSDHashOperator
|
|
js_gcroot_mapper(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 number,
|
|
void *arg)
|
|
{
|
|
GCRootMapArgs *args = (GCRootMapArgs *) arg;
|
|
JSGCRootHashEntry *rhe = (JSGCRootHashEntry *)hdr;
|
|
intN mapflags;
|
|
int op;
|
|
|
|
mapflags = args->map(rhe->root, rhe->name, args->data);
|
|
|
|
#if JS_MAP_GCROOT_NEXT == JS_DHASH_NEXT && \
|
|
JS_MAP_GCROOT_STOP == JS_DHASH_STOP && \
|
|
JS_MAP_GCROOT_REMOVE == JS_DHASH_REMOVE
|
|
op = (JSDHashOperator)mapflags;
|
|
#else
|
|
op = JS_DHASH_NEXT;
|
|
if (mapflags & JS_MAP_GCROOT_STOP)
|
|
op |= JS_DHASH_STOP;
|
|
if (mapflags & JS_MAP_GCROOT_REMOVE)
|
|
op |= JS_DHASH_REMOVE;
|
|
#endif
|
|
|
|
return (JSDHashOperator) op;
|
|
}
|
|
|
|
uint32
|
|
js_MapGCRoots(JSRuntime *rt, JSGCRootMapFun map, void *data)
|
|
{
|
|
GCRootMapArgs args;
|
|
uint32 rv;
|
|
|
|
args.map = map;
|
|
args.data = data;
|
|
JS_LOCK_GC(rt);
|
|
rv = JS_DHashTableEnumerate(&rt->gcRootsHash, js_gcroot_mapper, &args);
|
|
JS_UNLOCK_GC(rt);
|
|
return rv;
|
|
}
|
|
|
|
JSBool
|
|
js_RegisterCloseableIterator(JSContext *cx, JSObject *obj)
|
|
{
|
|
JSRuntime *rt;
|
|
JSBool ok;
|
|
|
|
rt = cx->runtime;
|
|
JS_ASSERT(!rt->gcRunning);
|
|
|
|
JS_LOCK_GC(rt);
|
|
ok = rt->gcIteratorTable.append(obj);
|
|
JS_UNLOCK_GC(rt);
|
|
return ok;
|
|
}
|
|
|
|
static void
|
|
CloseNativeIterators(JSContext *cx)
|
|
{
|
|
JSRuntime *rt = cx->runtime;
|
|
size_t length = rt->gcIteratorTable.length();
|
|
JSObject **array = rt->gcIteratorTable.begin();
|
|
|
|
size_t newLength = 0;
|
|
for (size_t i = 0; i < length; ++i) {
|
|
JSObject *obj = array[i];
|
|
if (js_IsAboutToBeFinalized(obj))
|
|
js_CloseNativeIterator(cx, obj);
|
|
else
|
|
array[newLength++] = obj;
|
|
}
|
|
rt->gcIteratorTable.resize(newLength);
|
|
}
|
|
|
|
void
|
|
JSRuntime::setGCTriggerFactor(uint32 factor)
|
|
{
|
|
JS_ASSERT(factor >= 100);
|
|
|
|
gcTriggerFactor = factor;
|
|
setGCLastBytes(gcLastBytes);
|
|
}
|
|
|
|
void
|
|
JSRuntime::setGCLastBytes(size_t lastBytes)
|
|
{
|
|
gcLastBytes = lastBytes;
|
|
uint64 triggerBytes = uint64(lastBytes) * uint64(gcTriggerFactor / 100);
|
|
if (triggerBytes != size_t(triggerBytes))
|
|
triggerBytes = size_t(-1);
|
|
gcTriggerBytes = size_t(triggerBytes);
|
|
}
|
|
|
|
void
|
|
JSGCFreeLists::purge()
|
|
{
|
|
/*
|
|
* Return the free list back to the arena so the GC finalization will not
|
|
* run the finalizers over unitialized bytes from free things.
|
|
*/
|
|
for (JSGCThing **p = finalizables; p != JS_ARRAY_END(finalizables); ++p) {
|
|
JSGCThing *freeListHead = *p;
|
|
if (freeListHead) {
|
|
JSGCArenaInfo *a = THING_TO_ARENA(freeListHead);
|
|
JS_ASSERT(!a->freeList);
|
|
a->freeList = freeListHead;
|
|
*p = NULL;
|
|
}
|
|
}
|
|
doubles = NULL;
|
|
}
|
|
|
|
void
|
|
JSGCFreeLists::moveTo(JSGCFreeLists *another)
|
|
{
|
|
*another = *this;
|
|
doubles = NULL;
|
|
memset(finalizables, 0, sizeof(finalizables));
|
|
JS_ASSERT(isEmpty());
|
|
}
|
|
|
|
static inline bool
|
|
IsGCThresholdReached(JSRuntime *rt)
|
|
{
|
|
#ifdef JS_GC_ZEAL
|
|
if (rt->gcZeal >= 1)
|
|
return true;
|
|
#endif
|
|
|
|
/*
|
|
* Since the initial value of the gcLastBytes parameter is not equal to
|
|
* zero (see the js_InitGC function) the return value is false when
|
|
* the gcBytes value is close to zero at the JS engine start.
|
|
*/
|
|
return rt->isGCMallocLimitReached() || rt->gcBytes >= rt->gcTriggerBytes;
|
|
}
|
|
|
|
static inline JSGCFreeLists *
|
|
GetGCFreeLists(JSContext *cx)
|
|
{
|
|
JSThreadData *td = JS_THREAD_DATA(cx);
|
|
if (!td->localRootStack)
|
|
return &td->gcFreeLists;
|
|
JS_ASSERT(td->gcFreeLists.isEmpty());
|
|
return &td->localRootStack->gcFreeLists;
|
|
}
|
|
|
|
static JSGCThing *
|
|
RefillFinalizableFreeList(JSContext *cx, unsigned thingKind)
|
|
{
|
|
JS_ASSERT(!GetGCFreeLists(cx)->finalizables[thingKind]);
|
|
JSRuntime *rt = cx->runtime;
|
|
JS_LOCK_GC(rt);
|
|
JS_ASSERT(!rt->gcRunning);
|
|
if (rt->gcRunning) {
|
|
METER(rt->gcStats.finalfail++);
|
|
JS_UNLOCK_GC(rt);
|
|
return NULL;
|
|
}
|
|
|
|
METER(JSGCArenaStats *astats = &cx->runtime->gcStats.arenaStats[thingKind]);
|
|
bool canGC = !JS_ON_TRACE(cx) && !JS_THREAD_DATA(cx)->waiveGCQuota;
|
|
bool doGC = canGC && IsGCThresholdReached(rt);
|
|
JSGCArenaList *arenaList = &rt->gcArenaList[thingKind];
|
|
JSGCArenaInfo *a;
|
|
for (;;) {
|
|
if (doGC) {
|
|
/*
|
|
* Keep rt->gcLock across the call into js_GC so we don't starve
|
|
* and lose to racing threads who deplete the heap just after
|
|
* js_GC has replenished it (or has synchronized with a racing
|
|
* GC that collected a bunch of garbage). This unfair scheduling
|
|
* can happen on certain operating systems. For the gory details,
|
|
* see bug 162779 at https://bugzilla.mozilla.org/.
|
|
*/
|
|
js_GC(cx, GC_LAST_DITCH);
|
|
METER(astats->retry++);
|
|
canGC = false;
|
|
|
|
/*
|
|
* The JSGC_END callback can legitimately allocate new GC things
|
|
* and populate the free list. If that happens, just return that
|
|
* list head.
|
|
*/
|
|
JSGCThing *freeList = GetGCFreeLists(cx)->finalizables[thingKind];
|
|
if (freeList) {
|
|
JS_UNLOCK_GC(rt);
|
|
return freeList;
|
|
}
|
|
}
|
|
|
|
while ((a = arenaList->cursor) != NULL) {
|
|
arenaList->cursor = a->prev;
|
|
JSGCThing *freeList = a->freeList;
|
|
if (freeList) {
|
|
a->freeList = NULL;
|
|
JS_UNLOCK_GC(rt);
|
|
return freeList;
|
|
}
|
|
}
|
|
|
|
a = NewGCArena(cx);
|
|
if (a)
|
|
break;
|
|
if (!canGC) {
|
|
METER(astats->fail++);
|
|
JS_UNLOCK_GC(rt);
|
|
return NULL;
|
|
}
|
|
doGC = true;
|
|
}
|
|
|
|
/*
|
|
* Do only minimal initialization of the arena inside the GC lock. We
|
|
* can do the rest outside the lock because no other threads will see
|
|
* the arena until the GC is run.
|
|
*/
|
|
a->list = arenaList;
|
|
a->prev = arenaList->head;
|
|
a->prevUnmarkedPage = 0;
|
|
a->freeList = NULL;
|
|
a->unmarkedChildren = 0;
|
|
arenaList->head = a;
|
|
JS_UNLOCK_GC(rt);
|
|
|
|
unsigned nthings = THINGS_PER_ARENA(arenaList->thingSize);
|
|
uint8 *flagsStart = THING_FLAGP(a, nthings - 1);
|
|
memset(flagsStart, 0, nthings);
|
|
|
|
/* Turn all things in the arena into a free list. */
|
|
return MakeNewArenaFreeList(a, arenaList->thingSize, nthings);
|
|
}
|
|
|
|
static inline void
|
|
CheckGCFreeListLink(JSGCThing *thing)
|
|
{
|
|
/*
|
|
* The GC things on the free lists come from one arena and the things on
|
|
* the free list are linked in ascending address order.
|
|
*/
|
|
JS_ASSERT_IF(thing->link,
|
|
THING_TO_ARENA(thing) == THING_TO_ARENA(thing->link));
|
|
JS_ASSERT_IF(thing->link, thing < thing->link);
|
|
}
|
|
|
|
void *
|
|
js_NewFinalizableGCThing(JSContext *cx, unsigned thingKind)
|
|
{
|
|
JS_ASSERT(thingKind < FINALIZE_LIMIT);
|
|
#ifdef JS_THREADSAFE
|
|
JS_ASSERT(cx->thread);
|
|
#endif
|
|
|
|
/* Updates of metering counters here may not be thread-safe. */
|
|
METER(cx->runtime->gcStats.arenaStats[thingKind].alloc++);
|
|
|
|
JSGCThing **freeListp =
|
|
JS_THREAD_DATA(cx)->gcFreeLists.finalizables + thingKind;
|
|
JSGCThing *thing = *freeListp;
|
|
if (thing) {
|
|
JS_ASSERT(!JS_THREAD_DATA(cx)->localRootStack);
|
|
*freeListp = thing->link;
|
|
cx->weakRoots.finalizableNewborns[thingKind] = thing;
|
|
CheckGCFreeListLink(thing);
|
|
METER(astats->localalloc++);
|
|
return thing;
|
|
}
|
|
|
|
/*
|
|
* To avoid for the local roots on each GC allocation when the local roots
|
|
* are not active we move the GC free lists from JSThreadData to lrs in
|
|
* JS_EnterLocalRootScope(). This way with inactive local roots we only
|
|
* check for non-null lrs only when we exhaust the free list.
|
|
*/
|
|
JSLocalRootStack *lrs = JS_THREAD_DATA(cx)->localRootStack;
|
|
for (;;) {
|
|
if (lrs) {
|
|
freeListp = lrs->gcFreeLists.finalizables + thingKind;
|
|
thing = *freeListp;
|
|
if (thing) {
|
|
*freeListp = thing->link;
|
|
METER(astats->localalloc++);
|
|
break;
|
|
}
|
|
}
|
|
|
|
thing = RefillFinalizableFreeList(cx, thingKind);
|
|
if (thing) {
|
|
/*
|
|
* See comments in RefillFinalizableFreeList about a possibility
|
|
* of *freeListp == thing.
|
|
*/
|
|
JS_ASSERT(!*freeListp || *freeListp == thing);
|
|
*freeListp = thing->link;
|
|
break;
|
|
}
|
|
|
|
js_ReportOutOfMemory(cx);
|
|
return NULL;
|
|
}
|
|
|
|
CheckGCFreeListLink(thing);
|
|
if (lrs) {
|
|
/*
|
|
* If we're in a local root scope, don't set newborn[type] at all, to
|
|
* avoid entraining garbage from it for an unbounded amount of time
|
|
* on this context. A caller will leave the local root scope and pop
|
|
* this reference, allowing thing to be GC'd if it has no other refs.
|
|
* See JS_EnterLocalRootScope and related APIs.
|
|
*/
|
|
if (js_PushLocalRoot(cx, lrs, (jsval) thing) < 0) {
|
|
JS_ASSERT(thing->link == *freeListp);
|
|
*freeListp = thing;
|
|
return NULL;
|
|
}
|
|
} else {
|
|
/*
|
|
* No local root scope, so we're stuck with the old, fragile model of
|
|
* depending on a pigeon-hole newborn per type per context.
|
|
*/
|
|
cx->weakRoots.finalizableNewborns[thingKind] = thing;
|
|
}
|
|
|
|
return thing;
|
|
}
|
|
|
|
static JSGCThing *
|
|
TurnUsedArenaIntoDoubleList(JSGCArenaInfo *a)
|
|
{
|
|
JSGCThing *head;
|
|
JSGCThing **tailp = &head;
|
|
jsuword thing = ARENA_INFO_TO_START(a);
|
|
|
|
/*
|
|
* When m below points the last bitmap's word in the arena, its high bits
|
|
* corresponds to non-existing cells and thingptr is outside the space
|
|
* allocated for doubles. ClearDoubleArenaFlags sets such bits to 1. Thus
|
|
* even for this last word its bit is unset iff the corresponding cell
|
|
* exists and free.
|
|
*/
|
|
for (jsbitmap *m = DOUBLE_ARENA_BITMAP(a);
|
|
m != DOUBLE_ARENA_BITMAP_END(a);
|
|
++m) {
|
|
JS_ASSERT(thing < reinterpret_cast<jsuword>(DOUBLE_ARENA_BITMAP(a)));
|
|
JS_ASSERT((thing - ARENA_INFO_TO_START(a)) %
|
|
(JS_BITS_PER_WORD * sizeof(jsdouble)) == 0);
|
|
|
|
jsbitmap bits = *m;
|
|
if (bits == jsbitmap(-1)) {
|
|
thing += JS_BITS_PER_WORD * sizeof(jsdouble);
|
|
} else {
|
|
/*
|
|
* We have some zero bits. Turn corresponding cells into a list
|
|
* unrolling the loop for better performance.
|
|
*/
|
|
const unsigned unroll = 4;
|
|
const jsbitmap unrollMask = (jsbitmap(1) << unroll) - 1;
|
|
JS_STATIC_ASSERT((JS_BITS_PER_WORD & unrollMask) == 0);
|
|
|
|
for (unsigned n = 0; n != JS_BITS_PER_WORD; n += unroll) {
|
|
jsbitmap bitsChunk = bits & unrollMask;
|
|
bits >>= unroll;
|
|
if (bitsChunk == unrollMask) {
|
|
thing += unroll * sizeof(jsdouble);
|
|
} else {
|
|
#define DO_BIT(bit) \
|
|
if (!(bitsChunk & (jsbitmap(1) << (bit)))) { \
|
|
JS_ASSERT(thing - ARENA_INFO_TO_START(a) <= \
|
|
(DOUBLES_PER_ARENA - 1) * sizeof(jsdouble));\
|
|
JSGCThing *t = reinterpret_cast<JSGCThing *>(thing); \
|
|
*tailp = t; \
|
|
tailp = &t->link; \
|
|
} \
|
|
thing += sizeof(jsdouble);
|
|
DO_BIT(0);
|
|
DO_BIT(1);
|
|
DO_BIT(2);
|
|
DO_BIT(3);
|
|
#undef DO_BIT
|
|
}
|
|
}
|
|
}
|
|
}
|
|
*tailp = NULL;
|
|
return head;
|
|
}
|
|
|
|
static JSGCThing *
|
|
RefillDoubleFreeList(JSContext *cx)
|
|
{
|
|
JS_ASSERT(!GetGCFreeLists(cx)->doubles);
|
|
|
|
JSRuntime *rt = cx->runtime;
|
|
JS_ASSERT(!rt->gcRunning);
|
|
|
|
JS_LOCK_GC(rt);
|
|
|
|
JSGCArenaInfo *a;
|
|
bool canGC = !JS_ON_TRACE(cx) && !JS_THREAD_DATA(cx)->waiveGCQuota;
|
|
bool doGC = canGC && IsGCThresholdReached(rt);
|
|
for (;;) {
|
|
if (doGC) {
|
|
js_GC(cx, GC_LAST_DITCH);
|
|
METER(rt->gcStats.doubleArenaStats.retry++);
|
|
canGC = false;
|
|
|
|
/* See comments in RefillFinalizableFreeList. */
|
|
JSGCThing *freeList = GetGCFreeLists(cx)->doubles;
|
|
if (freeList) {
|
|
JS_UNLOCK_GC(rt);
|
|
return freeList;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Loop until we find arena with some free doubles. We turn arenas
|
|
* into free lists outside the lock to minimize contention between
|
|
* threads.
|
|
*/
|
|
while (!!(a = rt->gcDoubleArenaList.cursor)) {
|
|
JS_ASSERT(!a->hasMarkedDoubles);
|
|
rt->gcDoubleArenaList.cursor = a->prev;
|
|
JS_UNLOCK_GC(rt);
|
|
JSGCThing *list = TurnUsedArenaIntoDoubleList(a);
|
|
if (list)
|
|
return list;
|
|
JS_LOCK_GC(rt);
|
|
}
|
|
a = NewGCArena(cx);
|
|
if (a)
|
|
break;
|
|
if (!canGC) {
|
|
METER(rt->gcStats.doubleArenaStats.fail++);
|
|
JS_UNLOCK_GC(rt);
|
|
return NULL;
|
|
}
|
|
doGC = true;
|
|
}
|
|
|
|
a->list = NULL;
|
|
a->freeList = NULL;
|
|
a->hasMarkedDoubles = false;
|
|
a->prev = rt->gcDoubleArenaList.head;
|
|
rt->gcDoubleArenaList.head = a;
|
|
JS_UNLOCK_GC(rt);
|
|
return MakeNewArenaFreeList(a, sizeof(jsdouble), DOUBLES_PER_ARENA);
|
|
}
|
|
|
|
JSBool
|
|
js_NewDoubleInRootedValue(JSContext *cx, jsdouble d, jsval *vp)
|
|
{
|
|
/* Updates of metering counters here are not thread-safe. */
|
|
METER(JSGCArenaStats *astats = &cx->runtime->gcStats.doubleArenaStats);
|
|
METER(astats->alloc++);
|
|
|
|
JSGCThing **freeListp = &JS_THREAD_DATA(cx)->gcFreeLists.doubles;
|
|
JSGCThing *thing = *freeListp;
|
|
if (thing) {
|
|
METER(astats->localalloc++);
|
|
JS_ASSERT(!JS_THREAD_DATA(cx)->localRootStack);
|
|
CheckGCFreeListLink(thing);
|
|
*freeListp = thing->link;
|
|
|
|
jsdouble *dp = reinterpret_cast<jsdouble *>(thing);
|
|
*dp = d;
|
|
*vp = DOUBLE_TO_JSVAL(dp);
|
|
return true;
|
|
}
|
|
|
|
JSLocalRootStack *lrs = JS_THREAD_DATA(cx)->localRootStack;
|
|
for (;;) {
|
|
if (lrs) {
|
|
freeListp = &lrs->gcFreeLists.doubles;
|
|
thing = *freeListp;
|
|
if (thing) {
|
|
METER(astats->localalloc++);
|
|
break;
|
|
}
|
|
}
|
|
thing = RefillDoubleFreeList(cx);
|
|
if (thing) {
|
|
JS_ASSERT(!*freeListp || *freeListp == thing);
|
|
break;
|
|
}
|
|
|
|
if (!JS_ON_TRACE(cx)) {
|
|
/* Trace code handle this on its own. */
|
|
js_ReportOutOfMemory(cx);
|
|
METER(astats->fail++);
|
|
}
|
|
return false;
|
|
}
|
|
|
|
CheckGCFreeListLink(thing);
|
|
*freeListp = thing->link;
|
|
|
|
jsdouble *dp = reinterpret_cast<jsdouble *>(thing);
|
|
*dp = d;
|
|
*vp = DOUBLE_TO_JSVAL(dp);
|
|
return !lrs || js_PushLocalRoot(cx, lrs, *vp) >= 0;
|
|
}
|
|
|
|
jsdouble *
|
|
js_NewWeaklyRootedDouble(JSContext *cx, jsdouble d)
|
|
{
|
|
jsval v;
|
|
if (!js_NewDoubleInRootedValue(cx, d, &v))
|
|
return NULL;
|
|
|
|
jsdouble *dp = JSVAL_TO_DOUBLE(v);
|
|
cx->weakRoots.newbornDouble = dp;
|
|
return dp;
|
|
}
|
|
|
|
/*
|
|
* Shallow GC-things can be locked just by setting the GCF_LOCK bit, because
|
|
* they have no descendants to mark during the GC. Currently the optimization
|
|
* is only used for non-dependant strings.
|
|
*/
|
|
static uint8 *
|
|
GetShallowGCThingFlag(void *thing)
|
|
{
|
|
if (JSString::isStatic(thing))
|
|
return NULL;
|
|
JSGCArenaInfo *a = THING_TO_ARENA(thing);
|
|
if (!a->list || !IsFinalizableStringKind(a->list->thingKind))
|
|
return NULL;
|
|
|
|
JS_ASSERT(sizeof(JSString) == a->list->thingSize);
|
|
JSString *str = (JSString *) thing;
|
|
if (str->isDependent())
|
|
return NULL;
|
|
|
|
uint32 index = THING_TO_INDEX(thing, sizeof(JSString));
|
|
return THING_FLAGP(a, index);
|
|
}
|
|
|
|
/* This is compatible with JSDHashEntryStub. */
|
|
typedef struct JSGCLockHashEntry {
|
|
JSDHashEntryHdr hdr;
|
|
const void *thing;
|
|
uint32 count;
|
|
} JSGCLockHashEntry;
|
|
|
|
JSBool
|
|
js_LockGCThingRT(JSRuntime *rt, void *thing)
|
|
{
|
|
if (!thing)
|
|
return JS_TRUE;
|
|
|
|
JS_LOCK_GC(rt);
|
|
|
|
/*
|
|
* Avoid adding a rt->gcLocksHash entry for shallow things until someone
|
|
* nests a lock.
|
|
*/
|
|
uint8 *flagp = GetShallowGCThingFlag(thing);
|
|
JSBool ok;
|
|
JSGCLockHashEntry *lhe;
|
|
if (flagp && !(*flagp & GCF_LOCK)) {
|
|
*flagp |= GCF_LOCK;
|
|
METER(rt->gcStats.lock++);
|
|
ok = JS_TRUE;
|
|
goto out;
|
|
}
|
|
|
|
if (!rt->gcLocksHash) {
|
|
rt->gcLocksHash = JS_NewDHashTable(JS_DHashGetStubOps(), NULL,
|
|
sizeof(JSGCLockHashEntry),
|
|
GC_ROOTS_SIZE);
|
|
if (!rt->gcLocksHash) {
|
|
ok = JS_FALSE;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
lhe = (JSGCLockHashEntry *)
|
|
JS_DHashTableOperate(rt->gcLocksHash, thing, JS_DHASH_ADD);
|
|
if (!lhe) {
|
|
ok = JS_FALSE;
|
|
goto out;
|
|
}
|
|
if (!lhe->thing) {
|
|
lhe->thing = thing;
|
|
lhe->count = 1;
|
|
} else {
|
|
JS_ASSERT(lhe->count >= 1);
|
|
lhe->count++;
|
|
}
|
|
|
|
METER(rt->gcStats.lock++);
|
|
ok = JS_TRUE;
|
|
out:
|
|
JS_UNLOCK_GC(rt);
|
|
return ok;
|
|
}
|
|
|
|
void
|
|
js_UnlockGCThingRT(JSRuntime *rt, void *thing)
|
|
{
|
|
if (!thing)
|
|
return;
|
|
|
|
JS_LOCK_GC(rt);
|
|
|
|
uint8 *flagp = GetShallowGCThingFlag(thing);
|
|
JSGCLockHashEntry *lhe;
|
|
if (flagp && !(*flagp & GCF_LOCK))
|
|
goto out;
|
|
if (!rt->gcLocksHash ||
|
|
(lhe = (JSGCLockHashEntry *)
|
|
JS_DHashTableOperate(rt->gcLocksHash, thing,
|
|
JS_DHASH_LOOKUP),
|
|
JS_DHASH_ENTRY_IS_FREE(&lhe->hdr))) {
|
|
/* Shallow entry is not in the hash -> clear its lock bit. */
|
|
if (flagp)
|
|
*flagp &= ~GCF_LOCK;
|
|
else
|
|
goto out;
|
|
} else {
|
|
if (--lhe->count != 0)
|
|
goto out;
|
|
JS_DHashTableOperate(rt->gcLocksHash, thing, JS_DHASH_REMOVE);
|
|
}
|
|
|
|
rt->gcPoke = JS_TRUE;
|
|
METER(rt->gcStats.unlock++);
|
|
out:
|
|
JS_UNLOCK_GC(rt);
|
|
}
|
|
|
|
JS_PUBLIC_API(void)
|
|
JS_TraceChildren(JSTracer *trc, void *thing, uint32 kind)
|
|
{
|
|
switch (kind) {
|
|
case JSTRACE_OBJECT: {
|
|
/* If obj has no map, it must be a newborn. */
|
|
JSObject *obj = (JSObject *) thing;
|
|
if (!obj->map)
|
|
break;
|
|
obj->map->ops->trace(trc, obj);
|
|
break;
|
|
}
|
|
|
|
case JSTRACE_STRING: {
|
|
JSString *str = (JSString *) thing;
|
|
if (str->isDependent())
|
|
JS_CALL_STRING_TRACER(trc, str->dependentBase(), "base");
|
|
break;
|
|
}
|
|
|
|
#if JS_HAS_XML_SUPPORT
|
|
case JSTRACE_XML:
|
|
js_TraceXML(trc, (JSXML *)thing);
|
|
break;
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
* When the native stack is low, the GC does not call JS_TraceChildren to mark
|
|
* the reachable "children" of the thing. Rather the thing is put aside and
|
|
* JS_TraceChildren is called later with more space on the C stack.
|
|
*
|
|
* To implement such delayed marking of the children with minimal overhead for
|
|
* the normal case of sufficient native stack, the code adds two fields to
|
|
* JSGCArenaInfo. The first field, JSGCArenaInfo::prevUnmarkedPage, links all
|
|
* arenas with delayed things into a stack list with the pointer to stack top
|
|
* in JSRuntime::gcUnmarkedArenaStackTop. DelayMarkingChildren adds arenas to
|
|
* the stack as necessary while MarkDelayedChildren pops the arenas from the
|
|
* stack until it empties.
|
|
*
|
|
* The second field, JSGCArenaInfo::unmarkedChildren, is a bitmap that tells
|
|
* for which things the GC should call JS_TraceChildren later. The bitmap is
|
|
* a single word. As such it does not pinpoint the delayed things in the arena
|
|
* but rather tells the intervals containing ThingsPerUnmarkedBit(thingSize)
|
|
* things. Later the code in MarkDelayedChildren discovers such intervals
|
|
* and calls JS_TraceChildren on any marked thing in the interval. This
|
|
* implies that JS_TraceChildren can be called many times for a single thing
|
|
* if the thing shares the same interval with some delayed things. This should
|
|
* be fine as any GC graph marking/traversing hooks must allow repeated calls
|
|
* during the same GC cycle. In particular, xpcom cycle collector relies on
|
|
* this.
|
|
*
|
|
* Note that such repeated scanning may slow down the GC. In particular, it is
|
|
* possible to construct an object graph where the GC calls JS_TraceChildren
|
|
* ThingsPerUnmarkedBit(thingSize) for almost all things in the graph. We
|
|
* tolerate this as the max value for ThingsPerUnmarkedBit(thingSize) is 4.
|
|
* This is archived for JSObject on 32 bit system as it is exactly JSObject
|
|
* that has the smallest size among the GC things that can be delayed. On 32
|
|
* bit CPU we have less than 128 objects per 4K GC arena so each bit in
|
|
* unmarkedChildren covers 4 objects.
|
|
*/
|
|
inline unsigned
|
|
ThingsPerUnmarkedBit(unsigned thingSize)
|
|
{
|
|
return JS_HOWMANY(THINGS_PER_ARENA(thingSize), JS_BITS_PER_WORD);
|
|
}
|
|
|
|
static void
|
|
DelayMarkingChildren(JSRuntime *rt, uint8 *flagp)
|
|
{
|
|
JSGCArenaInfo *a;
|
|
uint32 unmarkedBitIndex;
|
|
jsuword bit;
|
|
|
|
JS_ASSERT(*flagp & GCF_MARK);
|
|
|
|
METER(rt->gcStats.unmarked++);
|
|
a = FLAGP_TO_ARENA(flagp);
|
|
unmarkedBitIndex = FLAGP_TO_INDEX(flagp) /
|
|
ThingsPerUnmarkedBit(a->list->thingSize);
|
|
JS_ASSERT(unmarkedBitIndex < JS_BITS_PER_WORD);
|
|
bit = (jsuword)1 << unmarkedBitIndex;
|
|
if (a->unmarkedChildren != 0) {
|
|
JS_ASSERT(rt->gcUnmarkedArenaStackTop);
|
|
if (a->unmarkedChildren & bit) {
|
|
/* bit already covers things with children to mark later. */
|
|
return;
|
|
}
|
|
a->unmarkedChildren |= bit;
|
|
} else {
|
|
/*
|
|
* The thing is the first thing with not yet marked children in the
|
|
* whole arena, so push the arena on the stack of arenas with things
|
|
* to be marked later unless the arena has already been pushed. We
|
|
* detect that through checking prevUnmarkedPage as the field is 0
|
|
* only for not yet pushed arenas. To ensure that
|
|
* prevUnmarkedPage != 0
|
|
* even when the stack contains one element, we make prevUnmarkedPage
|
|
* for the arena at the bottom to point to itself.
|
|
*
|
|
* See comments in MarkDelayedChildren.
|
|
*/
|
|
a->unmarkedChildren = bit;
|
|
if (a->prevUnmarkedPage == 0) {
|
|
if (!rt->gcUnmarkedArenaStackTop) {
|
|
/* Stack was empty, mark the arena as the bottom element. */
|
|
a->prevUnmarkedPage = ARENA_INFO_TO_PAGE(a);
|
|
} else {
|
|
JS_ASSERT(rt->gcUnmarkedArenaStackTop->prevUnmarkedPage != 0);
|
|
a->prevUnmarkedPage =
|
|
ARENA_INFO_TO_PAGE(rt->gcUnmarkedArenaStackTop);
|
|
}
|
|
rt->gcUnmarkedArenaStackTop = a;
|
|
}
|
|
JS_ASSERT(rt->gcUnmarkedArenaStackTop);
|
|
}
|
|
#ifdef DEBUG
|
|
rt->gcMarkLaterCount += ThingsPerUnmarkedBit(a->list->thingSize);
|
|
METER_UPDATE_MAX(rt->gcStats.maxunmarked, rt->gcMarkLaterCount);
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
MarkDelayedChildren(JSTracer *trc)
|
|
{
|
|
JSRuntime *rt;
|
|
JSGCArenaInfo *a, *aprev;
|
|
uint32 thingSize, traceKind;
|
|
uint32 thingsPerUnmarkedBit;
|
|
uint32 unmarkedBitIndex, thingIndex, indexLimit, endIndex;
|
|
JSGCThing *thing;
|
|
uint8 *flagp;
|
|
|
|
rt = trc->context->runtime;
|
|
a = rt->gcUnmarkedArenaStackTop;
|
|
if (!a) {
|
|
JS_ASSERT(rt->gcMarkLaterCount == 0);
|
|
return;
|
|
}
|
|
|
|
for (;;) {
|
|
/*
|
|
* The following assert verifies that the current arena belongs to the
|
|
* unmarked stack, since DelayMarkingChildren ensures that even for
|
|
* the stack's bottom, prevUnmarkedPage != 0 but rather points to
|
|
* itself.
|
|
*/
|
|
JS_ASSERT(a->prevUnmarkedPage != 0);
|
|
JS_ASSERT(rt->gcUnmarkedArenaStackTop->prevUnmarkedPage != 0);
|
|
thingSize = a->list->thingSize;
|
|
traceKind = GetFinalizableArenaTraceKind(a);
|
|
indexLimit = THINGS_PER_ARENA(thingSize);
|
|
thingsPerUnmarkedBit = ThingsPerUnmarkedBit(thingSize);
|
|
|
|
/*
|
|
* We cannot use do-while loop here as a->unmarkedChildren can be zero
|
|
* before the loop as a leftover from the previous iterations. See
|
|
* comments after the loop.
|
|
*/
|
|
while (a->unmarkedChildren != 0) {
|
|
unmarkedBitIndex = JS_FLOOR_LOG2W(a->unmarkedChildren);
|
|
a->unmarkedChildren &= ~((jsuword)1 << unmarkedBitIndex);
|
|
#ifdef DEBUG
|
|
JS_ASSERT(rt->gcMarkLaterCount >= thingsPerUnmarkedBit);
|
|
rt->gcMarkLaterCount -= thingsPerUnmarkedBit;
|
|
#endif
|
|
thingIndex = unmarkedBitIndex * thingsPerUnmarkedBit;
|
|
endIndex = thingIndex + thingsPerUnmarkedBit;
|
|
|
|
/*
|
|
* endIndex can go beyond the last allocated thing as the real
|
|
* limit can be "inside" the bit.
|
|
*/
|
|
if (endIndex > indexLimit)
|
|
endIndex = indexLimit;
|
|
JS_ASSERT(thingIndex < indexLimit);
|
|
do {
|
|
flagp = THING_FLAGP(a, thingIndex);
|
|
if (*flagp & GCF_MARK) {
|
|
thing = FLAGP_TO_THING(flagp, thingSize);
|
|
JS_TraceChildren(trc, thing, traceKind);
|
|
}
|
|
} while (++thingIndex != endIndex);
|
|
}
|
|
|
|
/*
|
|
* We finished tracing of all things in the the arena but we can only
|
|
* pop it from the stack if the arena is the stack's top.
|
|
*
|
|
* When JS_TraceChildren from the above calls JS_CallTracer that in
|
|
* turn on low C stack calls DelayMarkingChildren and the latter
|
|
* pushes new arenas to the unmarked stack, we have to skip popping
|
|
* of this arena until it becomes the top of the stack again.
|
|
*/
|
|
if (a == rt->gcUnmarkedArenaStackTop) {
|
|
aprev = ARENA_PAGE_TO_INFO(a->prevUnmarkedPage);
|
|
a->prevUnmarkedPage = 0;
|
|
if (a == aprev) {
|
|
/*
|
|
* prevUnmarkedPage points to itself and we reached the
|
|
* bottom of the stack.
|
|
*/
|
|
break;
|
|
}
|
|
rt->gcUnmarkedArenaStackTop = a = aprev;
|
|
} else {
|
|
a = rt->gcUnmarkedArenaStackTop;
|
|
}
|
|
}
|
|
JS_ASSERT(rt->gcUnmarkedArenaStackTop);
|
|
JS_ASSERT(rt->gcUnmarkedArenaStackTop->prevUnmarkedPage == 0);
|
|
rt->gcUnmarkedArenaStackTop = NULL;
|
|
JS_ASSERT(rt->gcMarkLaterCount == 0);
|
|
}
|
|
|
|
JS_PUBLIC_API(void)
|
|
JS_CallTracer(JSTracer *trc, void *thing, uint32 kind)
|
|
{
|
|
JSContext *cx;
|
|
JSRuntime *rt;
|
|
JSGCArenaInfo *a;
|
|
uintN index;
|
|
uint8 *flagp;
|
|
|
|
JS_ASSERT(thing);
|
|
JS_ASSERT(JS_IS_VALID_TRACE_KIND(kind));
|
|
JS_ASSERT(trc->debugPrinter || trc->debugPrintArg);
|
|
|
|
if (!IS_GC_MARKING_TRACER(trc)) {
|
|
trc->callback(trc, thing, kind);
|
|
goto out;
|
|
}
|
|
|
|
cx = trc->context;
|
|
rt = cx->runtime;
|
|
JS_ASSERT(rt->gcMarkingTracer == trc);
|
|
JS_ASSERT(rt->gcLevel > 0);
|
|
|
|
/*
|
|
* Optimize for string and double as their size is known and their tracing
|
|
* is not recursive.
|
|
*/
|
|
switch (kind) {
|
|
case JSTRACE_DOUBLE:
|
|
a = THING_TO_ARENA(thing);
|
|
JS_ASSERT(!a->list);
|
|
if (!a->hasMarkedDoubles) {
|
|
ClearDoubleArenaFlags(a);
|
|
a->hasMarkedDoubles = true;
|
|
}
|
|
index = DOUBLE_THING_TO_INDEX(thing);
|
|
JS_SET_BIT(DOUBLE_ARENA_BITMAP(a), index);
|
|
goto out;
|
|
|
|
case JSTRACE_STRING:
|
|
for (;;) {
|
|
if (JSString::isStatic(thing))
|
|
goto out;
|
|
a = THING_TO_ARENA(thing);
|
|
flagp = THING_FLAGP(a, THING_TO_INDEX(thing, sizeof(JSString)));
|
|
JS_ASSERT(kind == GetFinalizableArenaTraceKind(a));
|
|
if (!((JSString *) thing)->isDependent()) {
|
|
*flagp |= GCF_MARK;
|
|
goto out;
|
|
}
|
|
if (*flagp & GCF_MARK)
|
|
goto out;
|
|
*flagp |= GCF_MARK;
|
|
thing = ((JSString *) thing)->dependentBase();
|
|
}
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
JS_ASSERT(kind == GetFinalizableArenaTraceKind(THING_TO_ARENA(thing)));
|
|
flagp = GetGCThingFlags(thing);
|
|
if (*flagp & GCF_MARK)
|
|
goto out;
|
|
|
|
*flagp |= GCF_MARK;
|
|
if (!cx->insideGCMarkCallback) {
|
|
/*
|
|
* With JS_GC_ASSUME_LOW_C_STACK defined the mark phase of GC always
|
|
* uses the non-recursive code that otherwise would be called only on
|
|
* a low C stack condition.
|
|
*/
|
|
#ifdef JS_GC_ASSUME_LOW_C_STACK
|
|
# define RECURSION_TOO_DEEP() JS_TRUE
|
|
#else
|
|
int stackDummy;
|
|
# define RECURSION_TOO_DEEP() (!JS_CHECK_STACK_SIZE(cx, stackDummy))
|
|
#endif
|
|
if (RECURSION_TOO_DEEP())
|
|
DelayMarkingChildren(rt, flagp);
|
|
else
|
|
JS_TraceChildren(trc, thing, kind);
|
|
} else {
|
|
/*
|
|
* For API compatibility we allow for the callback to assume that
|
|
* after it calls JS_MarkGCThing for the last time, the callback can
|
|
* start to finalize its own objects that are only referenced by
|
|
* unmarked GC things.
|
|
*
|
|
* Since we do not know which call from inside the callback is the
|
|
* last, we ensure that children of all marked things are traced and
|
|
* call MarkDelayedChildren(trc) after tracing the thing.
|
|
*
|
|
* As MarkDelayedChildren unconditionally invokes JS_TraceChildren
|
|
* for the things with unmarked children, calling DelayMarkingChildren
|
|
* is useless here. Hence we always trace thing's children even with a
|
|
* low native stack.
|
|
*/
|
|
cx->insideGCMarkCallback = JS_FALSE;
|
|
JS_TraceChildren(trc, thing, kind);
|
|
MarkDelayedChildren(trc);
|
|
cx->insideGCMarkCallback = JS_TRUE;
|
|
}
|
|
|
|
out:
|
|
#ifdef DEBUG
|
|
trc->debugPrinter = NULL;
|
|
trc->debugPrintArg = NULL;
|
|
#endif
|
|
return; /* to avoid out: right_curl when DEBUG is not defined */
|
|
}
|
|
|
|
void
|
|
js_CallValueTracerIfGCThing(JSTracer *trc, jsval v)
|
|
{
|
|
void *thing;
|
|
uint32 kind;
|
|
|
|
if (JSVAL_IS_DOUBLE(v) || JSVAL_IS_STRING(v)) {
|
|
thing = JSVAL_TO_TRACEABLE(v);
|
|
kind = JSVAL_TRACE_KIND(v);
|
|
JS_ASSERT(kind == js_GetGCThingTraceKind(thing));
|
|
} else if (JSVAL_IS_OBJECT(v) && v != JSVAL_NULL) {
|
|
/* v can be an arbitrary GC thing reinterpreted as an object. */
|
|
thing = JSVAL_TO_OBJECT(v);
|
|
kind = js_GetGCThingTraceKind(thing);
|
|
} else {
|
|
return;
|
|
}
|
|
JS_CallTracer(trc, thing, kind);
|
|
}
|
|
|
|
static JSDHashOperator
|
|
gc_root_traversal(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 num,
|
|
void *arg)
|
|
{
|
|
JSGCRootHashEntry *rhe = (JSGCRootHashEntry *)hdr;
|
|
JSTracer *trc = (JSTracer *)arg;
|
|
jsval *rp = (jsval *)rhe->root;
|
|
jsval v = *rp;
|
|
|
|
/* Ignore null reference, scalar values, and static strings. */
|
|
if (JSVAL_IS_TRACEABLE(v)) {
|
|
#ifdef DEBUG
|
|
if (!JSString::isStatic(JSVAL_TO_GCTHING(v))) {
|
|
bool root_points_to_gcArenaList = false;
|
|
jsuword thing = (jsuword) JSVAL_TO_GCTHING(v);
|
|
JSRuntime *rt = trc->context->runtime;
|
|
for (unsigned i = 0; i != FINALIZE_LIMIT; i++) {
|
|
JSGCArenaList *arenaList = &rt->gcArenaList[i];
|
|
size_t thingSize = arenaList->thingSize;
|
|
size_t limit = THINGS_PER_ARENA(thingSize) * thingSize;
|
|
for (JSGCArenaInfo *a = arenaList->head; a; a = a->prev) {
|
|
if (thing - ARENA_INFO_TO_START(a) < limit) {
|
|
root_points_to_gcArenaList = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (!root_points_to_gcArenaList) {
|
|
for (JSGCArenaInfo *a = rt->gcDoubleArenaList.head;
|
|
a;
|
|
a = a->prev) {
|
|
if (thing - ARENA_INFO_TO_START(a) <
|
|
DOUBLES_PER_ARENA * sizeof(jsdouble)) {
|
|
root_points_to_gcArenaList = true;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (!root_points_to_gcArenaList && rhe->name) {
|
|
fprintf(stderr,
|
|
"JS API usage error: the address passed to JS_AddNamedRoot currently holds an\n"
|
|
"invalid jsval. This is usually caused by a missing call to JS_RemoveRoot.\n"
|
|
"The root's name is \"%s\".\n",
|
|
rhe->name);
|
|
}
|
|
JS_ASSERT(root_points_to_gcArenaList);
|
|
}
|
|
#endif
|
|
JS_SET_TRACING_NAME(trc, rhe->name ? rhe->name : "root");
|
|
js_CallValueTracerIfGCThing(trc, v);
|
|
}
|
|
|
|
return JS_DHASH_NEXT;
|
|
}
|
|
|
|
static JSDHashOperator
|
|
gc_lock_traversal(JSDHashTable *table, JSDHashEntryHdr *hdr, uint32 num,
|
|
void *arg)
|
|
{
|
|
JSGCLockHashEntry *lhe = (JSGCLockHashEntry *)hdr;
|
|
void *thing = (void *)lhe->thing;
|
|
JSTracer *trc = (JSTracer *)arg;
|
|
uint32 traceKind;
|
|
|
|
JS_ASSERT(lhe->count >= 1);
|
|
traceKind = js_GetGCThingTraceKind(thing);
|
|
JS_CALL_TRACER(trc, thing, traceKind, "locked object");
|
|
return JS_DHASH_NEXT;
|
|
}
|
|
|
|
#define TRACE_JSVALS(trc, len, vec, name) \
|
|
JS_BEGIN_MACRO \
|
|
jsval _v, *_vp, *_end; \
|
|
\
|
|
for (_vp = vec, _end = _vp + len; _vp < _end; _vp++) { \
|
|
_v = *_vp; \
|
|
if (JSVAL_IS_TRACEABLE(_v)) { \
|
|
JS_SET_TRACING_INDEX(trc, name, _vp - (vec)); \
|
|
JS_CallTracer(trc, JSVAL_TO_TRACEABLE(_v), \
|
|
JSVAL_TRACE_KIND(_v)); \
|
|
} \
|
|
} \
|
|
JS_END_MACRO
|
|
|
|
void
|
|
js_TraceStackFrame(JSTracer *trc, JSStackFrame *fp)
|
|
{
|
|
uintN nslots, minargs, skip;
|
|
|
|
if (fp->callobj)
|
|
JS_CALL_OBJECT_TRACER(trc, fp->callobj, "call");
|
|
if (fp->argsobj)
|
|
JS_CALL_OBJECT_TRACER(trc, JSVAL_TO_OBJECT(fp->argsobj), "arguments");
|
|
if (fp->varobj)
|
|
JS_CALL_OBJECT_TRACER(trc, fp->varobj, "variables");
|
|
if (fp->script) {
|
|
js_TraceScript(trc, fp->script);
|
|
|
|
/* fp->slots is null for watch pseudo-frames, see js_watch_set. */
|
|
if (fp->slots) {
|
|
/*
|
|
* Don't mark what has not been pushed yet, or what has been
|
|
* popped already.
|
|
*/
|
|
if (fp->regs && fp->regs->sp) {
|
|
nslots = (uintN) (fp->regs->sp - fp->slots);
|
|
JS_ASSERT(nslots >= fp->script->nfixed);
|
|
} else {
|
|
nslots = fp->script->nfixed;
|
|
}
|
|
TRACE_JSVALS(trc, nslots, fp->slots, "slot");
|
|
}
|
|
} else {
|
|
JS_ASSERT(!fp->slots);
|
|
JS_ASSERT(!fp->regs);
|
|
}
|
|
|
|
/* Allow for primitive this parameter due to JSFUN_THISP_* flags. */
|
|
JS_CALL_VALUE_TRACER(trc, fp->thisv, "this");
|
|
|
|
if (fp->argv) {
|
|
JS_CALL_VALUE_TRACER(trc, fp->calleeValue(), "callee");
|
|
nslots = fp->argc;
|
|
skip = 0;
|
|
if (fp->fun) {
|
|
minargs = FUN_MINARGS(fp->fun);
|
|
if (minargs > nslots)
|
|
nslots = minargs;
|
|
if (!FUN_INTERPRETED(fp->fun)) {
|
|
JS_ASSERT(!(fp->fun->flags & JSFUN_FAST_NATIVE));
|
|
nslots += fp->fun->u.n.extra;
|
|
}
|
|
if (fp->fun->flags & JSFRAME_ROOTED_ARGV)
|
|
skip = 2 + fp->argc;
|
|
}
|
|
TRACE_JSVALS(trc, 2 + nslots - skip, fp->argv - 2 + skip, "operand");
|
|
}
|
|
|
|
JS_CALL_VALUE_TRACER(trc, fp->rval, "rval");
|
|
if (fp->scopeChain)
|
|
JS_CALL_OBJECT_TRACER(trc, fp->scopeChain, "scope chain");
|
|
}
|
|
|
|
void
|
|
JSWeakRoots::mark(JSTracer *trc)
|
|
{
|
|
#ifdef DEBUG
|
|
const char * const newbornNames[] = {
|
|
"newborn_object", /* FINALIZE_OBJECT */
|
|
"newborn_function", /* FINALIZE_FUNCTION */
|
|
#if JS_HAS_XML_SUPPORT
|
|
"newborn_xml", /* FINALIZE_XML */
|
|
#endif
|
|
"newborn_string", /* FINALIZE_STRING */
|
|
"newborn_external_string0", /* FINALIZE_EXTERNAL_STRING0 */
|
|
"newborn_external_string1", /* FINALIZE_EXTERNAL_STRING1 */
|
|
"newborn_external_string2", /* FINALIZE_EXTERNAL_STRING2 */
|
|
"newborn_external_string3", /* FINALIZE_EXTERNAL_STRING3 */
|
|
"newborn_external_string4", /* FINALIZE_EXTERNAL_STRING4 */
|
|
"newborn_external_string5", /* FINALIZE_EXTERNAL_STRING5 */
|
|
"newborn_external_string6", /* FINALIZE_EXTERNAL_STRING6 */
|
|
"newborn_external_string7", /* FINALIZE_EXTERNAL_STRING7 */
|
|
};
|
|
#endif
|
|
for (size_t i = 0; i != JS_ARRAY_LENGTH(finalizableNewborns); ++i) {
|
|
void *newborn = finalizableNewborns[i];
|
|
if (newborn) {
|
|
JS_CALL_TRACER(trc, newborn, GetFinalizableTraceKind(i),
|
|
newbornNames[i]);
|
|
}
|
|
}
|
|
if (newbornDouble)
|
|
JS_CALL_DOUBLE_TRACER(trc, newbornDouble, "newborn_double");
|
|
JS_CALL_VALUE_TRACER(trc, lastAtom, "lastAtom");
|
|
JS_SET_TRACING_NAME(trc, "lastInternalResult");
|
|
js_CallValueTracerIfGCThing(trc, lastInternalResult);
|
|
}
|
|
|
|
JS_REQUIRES_STACK JS_FRIEND_API(void)
|
|
js_TraceContext(JSTracer *trc, JSContext *acx)
|
|
{
|
|
JSStackFrame *fp, *nextChain;
|
|
JSStackHeader *sh;
|
|
JSTempValueRooter *tvr;
|
|
|
|
if (IS_GC_MARKING_TRACER(trc)) {
|
|
|
|
#define FREE_OLD_ARENAS(pool) \
|
|
JS_BEGIN_MACRO \
|
|
int64 _age; \
|
|
JSArena * _a = (pool).current; \
|
|
if (_a == (pool).first.next && \
|
|
_a->avail == _a->base + sizeof(int64)) { \
|
|
_age = JS_Now() - *(int64 *) _a->base; \
|
|
if (_age > (int64) acx->runtime->gcEmptyArenaPoolLifespan * \
|
|
1000) \
|
|
JS_FreeArenaPool(&(pool)); \
|
|
} \
|
|
JS_END_MACRO
|
|
|
|
/*
|
|
* Release the stackPool's arenas if the stackPool has existed for
|
|
* longer than the limit specified by gcEmptyArenaPoolLifespan.
|
|
*/
|
|
FREE_OLD_ARENAS(acx->stackPool);
|
|
|
|
/*
|
|
* Release the regexpPool's arenas based on the same criterion as for
|
|
* the stackPool.
|
|
*/
|
|
FREE_OLD_ARENAS(acx->regexpPool);
|
|
}
|
|
|
|
/*
|
|
* Iterate frame chain and dormant chains.
|
|
*
|
|
* (NB: see comment on this whole "dormant" thing in js_Execute.)
|
|
*
|
|
* Since js_GetTopStackFrame needs to dereference cx->thread to check for
|
|
* JIT frames, we check for non-null thread here and avoid null checks
|
|
* there. See bug 471197.
|
|
*/
|
|
#ifdef JS_THREADSAFE
|
|
if (acx->thread)
|
|
#endif
|
|
{
|
|
fp = js_GetTopStackFrame(acx);
|
|
nextChain = acx->dormantFrameChain;
|
|
if (!fp)
|
|
goto next_chain;
|
|
|
|
/* The top frame must not be dormant. */
|
|
JS_ASSERT(!fp->dormantNext);
|
|
for (;;) {
|
|
do {
|
|
js_TraceStackFrame(trc, fp);
|
|
} while ((fp = fp->down) != NULL);
|
|
|
|
next_chain:
|
|
if (!nextChain)
|
|
break;
|
|
fp = nextChain;
|
|
nextChain = nextChain->dormantNext;
|
|
}
|
|
}
|
|
|
|
/* Mark other roots-by-definition in acx. */
|
|
if (acx->globalObject && !JS_HAS_OPTION(acx, JSOPTION_UNROOTED_GLOBAL))
|
|
JS_CALL_OBJECT_TRACER(trc, acx->globalObject, "global object");
|
|
acx->weakRoots.mark(trc);
|
|
if (acx->throwing) {
|
|
JS_CALL_VALUE_TRACER(trc, acx->exception, "exception");
|
|
} else {
|
|
/* Avoid keeping GC-ed junk stored in JSContext.exception. */
|
|
acx->exception = JSVAL_NULL;
|
|
}
|
|
|
|
for (sh = acx->stackHeaders; sh; sh = sh->down) {
|
|
METER(trc->context->runtime->gcStats.stackseg++);
|
|
METER(trc->context->runtime->gcStats.segslots += sh->nslots);
|
|
TRACE_JSVALS(trc, sh->nslots, JS_STACK_SEGMENT(sh), "stack");
|
|
}
|
|
|
|
for (tvr = acx->tempValueRooters; tvr; tvr = tvr->down) {
|
|
switch (tvr->count) {
|
|
case JSTVU_SINGLE:
|
|
JS_SET_TRACING_NAME(trc, "tvr->u.value");
|
|
js_CallValueTracerIfGCThing(trc, tvr->u.value);
|
|
break;
|
|
case JSTVU_TRACE:
|
|
tvr->u.trace(trc, tvr);
|
|
break;
|
|
case JSTVU_SPROP:
|
|
tvr->u.sprop->trace(trc);
|
|
break;
|
|
case JSTVU_WEAK_ROOTS:
|
|
tvr->u.weakRoots->mark(trc);
|
|
break;
|
|
case JSTVU_COMPILER:
|
|
tvr->u.compiler->trace(trc);
|
|
break;
|
|
case JSTVU_SCRIPT:
|
|
js_TraceScript(trc, tvr->u.script);
|
|
break;
|
|
case JSTVU_ENUMERATOR:
|
|
static_cast<JSAutoEnumStateRooter *>(tvr)->mark(trc);
|
|
break;
|
|
default:
|
|
JS_ASSERT(tvr->count >= 0);
|
|
TRACE_JSVALS(trc, tvr->count, tvr->u.array, "tvr->u.array");
|
|
}
|
|
}
|
|
|
|
if (acx->sharpObjectMap.depth > 0)
|
|
js_TraceSharpMap(trc, &acx->sharpObjectMap);
|
|
|
|
js_TraceRegExpStatics(trc, acx);
|
|
|
|
#ifdef JS_TRACER
|
|
InterpState* state = acx->interpState;
|
|
while (state) {
|
|
if (state->nativeVp)
|
|
TRACE_JSVALS(trc, state->nativeVpLen, state->nativeVp, "nativeVp");
|
|
state = state->prev;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
JS_REQUIRES_STACK void
|
|
js_TraceRuntime(JSTracer *trc, JSBool allAtoms)
|
|
{
|
|
JSRuntime *rt = trc->context->runtime;
|
|
JSContext *iter, *acx;
|
|
|
|
JS_DHashTableEnumerate(&rt->gcRootsHash, gc_root_traversal, trc);
|
|
if (rt->gcLocksHash)
|
|
JS_DHashTableEnumerate(rt->gcLocksHash, gc_lock_traversal, trc);
|
|
js_TraceAtomState(trc, allAtoms);
|
|
js_TraceRuntimeNumberState(trc);
|
|
js_MarkTraps(trc);
|
|
|
|
iter = NULL;
|
|
while ((acx = js_ContextIterator(rt, JS_TRUE, &iter)) != NULL)
|
|
js_TraceContext(trc, acx);
|
|
|
|
js_TraceThreads(rt, trc);
|
|
|
|
if (rt->gcExtraRootsTraceOp)
|
|
rt->gcExtraRootsTraceOp(trc, rt->gcExtraRootsData);
|
|
|
|
#ifdef JS_TRACER
|
|
for (int i = 0; i < JSBUILTIN_LIMIT; i++) {
|
|
if (rt->builtinFunctions[i])
|
|
JS_CALL_OBJECT_TRACER(trc, rt->builtinFunctions[i], "builtin function");
|
|
}
|
|
#endif
|
|
}
|
|
|
|
void
|
|
js_TriggerGC(JSContext *cx, JSBool gcLocked)
|
|
{
|
|
JSRuntime *rt = cx->runtime;
|
|
|
|
#ifdef JS_THREADSAFE
|
|
JS_ASSERT(cx->requestDepth > 0);
|
|
#endif
|
|
JS_ASSERT(!rt->gcRunning);
|
|
if (rt->gcIsNeeded)
|
|
return;
|
|
|
|
js_TriggerAllOperationCallbacks(rt, gcLocked);
|
|
}
|
|
|
|
static void
|
|
ProcessSetSlotRequest(JSContext *cx, JSSetSlotRequest *ssr)
|
|
{
|
|
JSObject *obj = ssr->obj;
|
|
JSObject *pobj = ssr->pobj;
|
|
uint32 slot = ssr->slot;
|
|
|
|
while (pobj) {
|
|
pobj = js_GetWrappedObject(cx, pobj);
|
|
if (pobj == obj) {
|
|
ssr->cycle = true;
|
|
return;
|
|
}
|
|
pobj = JSVAL_TO_OBJECT(STOBJ_GET_SLOT(pobj, slot));
|
|
}
|
|
|
|
pobj = ssr->pobj;
|
|
if (slot == JSSLOT_PROTO) {
|
|
obj->setProto(pobj);
|
|
} else {
|
|
JS_ASSERT(slot == JSSLOT_PARENT);
|
|
obj->setParent(pobj);
|
|
}
|
|
}
|
|
|
|
void
|
|
js_DestroyScriptsToGC(JSContext *cx, JSThreadData *data)
|
|
{
|
|
JSScript **listp, *script;
|
|
|
|
for (size_t i = 0; i != JS_ARRAY_LENGTH(data->scriptsToGC); ++i) {
|
|
listp = &data->scriptsToGC[i];
|
|
while ((script = *listp) != NULL) {
|
|
*listp = script->u.nextToGC;
|
|
script->u.nextToGC = NULL;
|
|
js_DestroyScript(cx, script);
|
|
}
|
|
}
|
|
}
|
|
|
|
static inline void
|
|
FinalizeGCThing(JSContext *cx, JSObject *obj, unsigned thingKind)
|
|
{
|
|
JS_ASSERT(thingKind == FINALIZE_FUNCTION || thingKind == FINALIZE_OBJECT);
|
|
|
|
/* Cope with stillborn objects that have no map. */
|
|
if (!obj->map)
|
|
return;
|
|
|
|
if (JS_UNLIKELY(cx->debugHooks->objectHook != NULL)) {
|
|
cx->debugHooks->objectHook(cx, obj, JS_FALSE,
|
|
cx->debugHooks->objectHookData);
|
|
}
|
|
|
|
/* Finalize obj first, in case it needs map and slots. */
|
|
JSClass *clasp = STOBJ_GET_CLASS(obj);
|
|
if (clasp->finalize)
|
|
clasp->finalize(cx, obj);
|
|
|
|
#ifdef INCLUDE_MOZILLA_DTRACE
|
|
if (JAVASCRIPT_OBJECT_FINALIZE_ENABLED())
|
|
jsdtrace_object_finalize(obj);
|
|
#endif
|
|
|
|
if (JS_LIKELY(OBJ_IS_NATIVE(obj)))
|
|
OBJ_SCOPE(obj)->drop(cx, obj);
|
|
js_FreeSlots(cx, obj);
|
|
}
|
|
|
|
static inline void
|
|
FinalizeGCThing(JSContext *cx, JSFunction *fun, unsigned thingKind)
|
|
{
|
|
JS_ASSERT(thingKind == FINALIZE_FUNCTION);
|
|
::FinalizeGCThing(cx, FUN_OBJECT(fun), thingKind);
|
|
}
|
|
|
|
#if JS_HAS_XML_SUPPORT
|
|
static inline void
|
|
FinalizeGCThing(JSContext *cx, JSXML *xml, unsigned thingKind)
|
|
{
|
|
js_FinalizeXML(cx, xml);
|
|
}
|
|
#endif
|
|
|
|
JS_STATIC_ASSERT(JS_EXTERNAL_STRING_LIMIT == 8);
|
|
static JSStringFinalizeOp str_finalizers[JS_EXTERNAL_STRING_LIMIT] = {
|
|
NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
|
|
};
|
|
|
|
intN
|
|
js_ChangeExternalStringFinalizer(JSStringFinalizeOp oldop,
|
|
JSStringFinalizeOp newop)
|
|
{
|
|
for (uintN i = 0; i != JS_ARRAY_LENGTH(str_finalizers); i++) {
|
|
if (str_finalizers[i] == oldop) {
|
|
str_finalizers[i] = newop;
|
|
return intN(i);
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
/*
|
|
* cx is NULL when we are called from js_FinishAtomState to force the
|
|
* finalization of the permanently interned strings.
|
|
*/
|
|
static void
|
|
FinalizeString(JSRuntime *rt, JSString *str, unsigned thingKind, JSContext *cx)
|
|
{
|
|
jschar *chars;
|
|
JSBool valid;
|
|
JSStringFinalizeOp finalizer;
|
|
|
|
JS_RUNTIME_UNMETER(rt, liveStrings);
|
|
JS_ASSERT(!JSString::isStatic(str));
|
|
JS_ASSERT(IsFinalizableStringKind(thingKind));
|
|
if (str->isDependent()) {
|
|
/* A dependent string can not be external and must be valid. */
|
|
JS_ASSERT(thingKind == FINALIZE_STRING);
|
|
JS_ASSERT(str->dependentBase());
|
|
JS_RUNTIME_UNMETER(rt, liveDependentStrings);
|
|
valid = JS_TRUE;
|
|
} else {
|
|
/* A stillborn string has null chars, so is not valid. */
|
|
chars = str->flatChars();
|
|
valid = (chars != NULL);
|
|
if (valid) {
|
|
if (thingKind == FINALIZE_STRING) {
|
|
if (cx)
|
|
cx->free(chars);
|
|
else
|
|
rt->free(chars);
|
|
} else {
|
|
unsigned type = thingKind - FINALIZE_EXTERNAL_STRING0;
|
|
JS_ASSERT(type < JS_ARRAY_LENGTH(str_finalizers));
|
|
finalizer = str_finalizers[type];
|
|
if (finalizer) {
|
|
/*
|
|
* Assume that the finalizer for the permanently interned
|
|
* string knows how to deal with null context.
|
|
*/
|
|
finalizer(cx, str);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (valid && str->isDeflated())
|
|
js_PurgeDeflatedStringCache(rt, str);
|
|
}
|
|
|
|
static inline void
|
|
FinalizeGCThing(JSContext *cx, JSString *str, unsigned thingKind)
|
|
{
|
|
return FinalizeString(cx->runtime, str, thingKind, cx);
|
|
}
|
|
|
|
void
|
|
js_FinalizeStringRT(JSRuntime *rt, JSString *str)
|
|
{
|
|
JS_ASSERT(!JSString::isStatic(str));
|
|
|
|
unsigned thingKind = THING_TO_ARENA(str)->list->thingKind;
|
|
FinalizeString(rt, str, thingKind, NULL);
|
|
}
|
|
|
|
template<typename T>
|
|
static void
|
|
FinalizeArenaList(JSContext *cx, unsigned thingKind,
|
|
JSGCArenaInfo **emptyArenas)
|
|
{
|
|
JSGCArenaList *arenaList = &cx->runtime->gcArenaList[thingKind];
|
|
JS_ASSERT(sizeof(T) == arenaList->thingSize);
|
|
|
|
JSGCArenaInfo **ap = &arenaList->head;
|
|
JSGCArenaInfo *a = *ap;
|
|
if (!a)
|
|
return;
|
|
|
|
#ifdef JS_GCMETER
|
|
uint32 nlivearenas = 0, nkilledarenas = 0, nthings = 0;
|
|
#endif
|
|
for (;;) {
|
|
JS_ASSERT(a->list == arenaList);
|
|
JS_ASSERT(a->prevUnmarkedPage == 0);
|
|
JS_ASSERT(a->unmarkedChildren == 0);
|
|
|
|
JSGCThing *freeList = NULL;
|
|
JSGCThing **tailp = &freeList;
|
|
bool allClear = true;
|
|
uint8 *flagp = THING_FLAGP(a, 0);
|
|
JSGCThing *thing =
|
|
reinterpret_cast<JSGCThing *>(ARENA_INFO_TO_START(a));
|
|
JSGCThing *thingsEnd =
|
|
reinterpret_cast<JSGCThing *>(ARENA_INFO_TO_START(a) +
|
|
THINGS_PER_ARENA(sizeof(T)) *
|
|
sizeof(T));
|
|
JSGCThing* nextFree = a->freeList ? a->freeList : thingsEnd;
|
|
for (;; thing = NextThing(thing, sizeof(T)), --flagp) {
|
|
if (thing == nextFree) {
|
|
if (thing == thingsEnd)
|
|
break;
|
|
JS_ASSERT(!*flagp);
|
|
nextFree = nextFree->link;
|
|
if (!nextFree) {
|
|
nextFree = thingsEnd;
|
|
} else {
|
|
JS_ASSERT(thing < nextFree);
|
|
JS_ASSERT(nextFree < thingsEnd);
|
|
}
|
|
} else {
|
|
JS_ASSERT(!(*flagp & ~(GCF_MARK | GCF_LOCK)));
|
|
if (*flagp) {
|
|
*flagp &= ~GCF_MARK;
|
|
allClear = false;
|
|
METER(nthings++);
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Call the finalizer with cleared flags so
|
|
* js_IsAboutToBeFinalized will be false.
|
|
*/
|
|
*flagp = 0;
|
|
::FinalizeGCThing(cx, reinterpret_cast<T *>(thing), thingKind);
|
|
#ifdef DEBUG
|
|
memset(thing, JS_FREE_PATTERN, sizeof(T));
|
|
#endif
|
|
}
|
|
*tailp = thing;
|
|
tailp = &thing->link;
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
/* Check that the free list is consistent. */
|
|
unsigned nfree = 0;
|
|
if (freeList) {
|
|
JS_ASSERT(tailp != &freeList);
|
|
JSGCThing *thing = freeList;
|
|
for (;;) {
|
|
++nfree;
|
|
if (&thing->link == tailp)
|
|
break;
|
|
JS_ASSERT(thing < thing->link);
|
|
thing = thing->link;
|
|
}
|
|
}
|
|
#endif
|
|
if (allClear) {
|
|
/*
|
|
* Forget just assembled free list head for the arena and
|
|
* add the arena itself to the destroy list.
|
|
*/
|
|
JS_ASSERT(nfree == THINGS_PER_ARENA(sizeof(T)));
|
|
*ap = a->prev;
|
|
a->prev = *emptyArenas;
|
|
*emptyArenas = a;
|
|
METER(nkilledarenas++);
|
|
} else {
|
|
JS_ASSERT(nfree < THINGS_PER_ARENA(sizeof(T)));
|
|
*tailp = NULL;
|
|
a->freeList = freeList;
|
|
ap = &a->prev;
|
|
METER(nlivearenas++);
|
|
}
|
|
if (!(a = *ap))
|
|
break;
|
|
}
|
|
arenaList->cursor = arenaList->head;
|
|
|
|
METER(UpdateArenaStats(&rt->gcStats.arenaStats[thingKind],
|
|
nlivearenas, nkilledarenas, nthings));
|
|
}
|
|
|
|
/*
|
|
* The gckind flag bit GC_LOCK_HELD indicates a call from js_NewGCThing with
|
|
* rt->gcLock already held, so the lock should be kept on return.
|
|
*/
|
|
void
|
|
js_GC(JSContext *cx, JSGCInvocationKind gckind)
|
|
{
|
|
JSRuntime *rt;
|
|
JSBool keepAtoms;
|
|
JSGCCallback callback;
|
|
JSTracer trc;
|
|
JSGCArenaInfo *emptyArenas, *a, **ap;
|
|
#ifdef JS_THREADSAFE
|
|
uint32 requestDebit;
|
|
#endif
|
|
#ifdef JS_GCMETER
|
|
uint32 nlivearenas, nkilledarenas, nthings;
|
|
#endif
|
|
|
|
JS_ASSERT_IF(gckind == GC_LAST_DITCH, !JS_ON_TRACE(cx));
|
|
rt = cx->runtime;
|
|
|
|
#ifdef JS_THREADSAFE
|
|
/*
|
|
* We allow js_GC calls outside a request but the context must be bound
|
|
* to the current thread.
|
|
*/
|
|
JS_ASSERT(CURRENT_THREAD_IS_ME(cx->thread));
|
|
|
|
/* Avoid deadlock. */
|
|
JS_ASSERT(!JS_IS_RUNTIME_LOCKED(rt));
|
|
#endif
|
|
|
|
if (gckind & GC_KEEP_ATOMS) {
|
|
/*
|
|
* The set slot request and last ditch GC kinds preserve all atoms and
|
|
* weak roots.
|
|
*/
|
|
keepAtoms = JS_TRUE;
|
|
} else {
|
|
/* Keep atoms when a suspended compile is running on another context. */
|
|
keepAtoms = (rt->gcKeepAtoms != 0);
|
|
JS_CLEAR_WEAK_ROOTS(&cx->weakRoots);
|
|
}
|
|
|
|
/*
|
|
* Don't collect garbage if the runtime isn't up, and cx is not the last
|
|
* context in the runtime. The last context must force a GC, and nothing
|
|
* should suppress that final collection or there may be shutdown leaks,
|
|
* or runtime bloat until the next context is created.
|
|
*/
|
|
if (rt->state != JSRTS_UP && gckind != GC_LAST_CONTEXT)
|
|
return;
|
|
|
|
restart_at_beginning:
|
|
/*
|
|
* Let the API user decide to defer a GC if it wants to (unless this
|
|
* is the last context). Invoke the callback regardless. Sample the
|
|
* callback in case we are freely racing with a JS_SetGCCallback{,RT} on
|
|
* another thread.
|
|
*/
|
|
if (gckind != GC_SET_SLOT_REQUEST && (callback = rt->gcCallback)) {
|
|
JSBool ok;
|
|
|
|
if (gckind & GC_LOCK_HELD)
|
|
JS_UNLOCK_GC(rt);
|
|
ok = callback(cx, JSGC_BEGIN);
|
|
if (gckind & GC_LOCK_HELD)
|
|
JS_LOCK_GC(rt);
|
|
if (!ok && gckind != GC_LAST_CONTEXT) {
|
|
/*
|
|
* It's possible that we've looped back to this code from the 'goto
|
|
* restart_at_beginning' below in the GC_SET_SLOT_REQUEST code and
|
|
* that rt->gcLevel is now 0. Don't return without notifying!
|
|
*/
|
|
if (rt->gcLevel == 0 && (gckind & GC_LOCK_HELD))
|
|
JS_NOTIFY_GC_DONE(rt);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Lock out other GC allocator and collector invocations. */
|
|
if (!(gckind & GC_LOCK_HELD))
|
|
JS_LOCK_GC(rt);
|
|
|
|
METER(rt->gcStats.poke++);
|
|
rt->gcPoke = JS_FALSE;
|
|
|
|
#ifdef JS_THREADSAFE
|
|
/*
|
|
* Check if the GC is already running on this or another thread and
|
|
* delegate the job to it.
|
|
*/
|
|
if (rt->gcLevel > 0) {
|
|
JS_ASSERT(rt->gcThread);
|
|
|
|
/* Bump gcLevel to restart the current GC, so it finds new garbage. */
|
|
rt->gcLevel++;
|
|
METER_UPDATE_MAX(rt->gcStats.maxlevel, rt->gcLevel);
|
|
|
|
/*
|
|
* If the GC runs on another thread, temporarily suspend the current
|
|
* request and wait until the GC is done.
|
|
*/
|
|
if (rt->gcThread != cx->thread) {
|
|
requestDebit = js_DiscountRequestsForGC(cx);
|
|
js_RecountRequestsAfterGC(rt, requestDebit);
|
|
}
|
|
if (!(gckind & GC_LOCK_HELD))
|
|
JS_UNLOCK_GC(rt);
|
|
return;
|
|
}
|
|
|
|
/* No other thread is in GC, so indicate that we're now in GC. */
|
|
rt->gcLevel = 1;
|
|
rt->gcThread = cx->thread;
|
|
|
|
/*
|
|
* Notify all operation callbacks, which will give them a chance to
|
|
* yield their current request. Contexts that are not currently
|
|
* executing will perform their callback at some later point,
|
|
* which then will be unnecessary, but harmless.
|
|
*/
|
|
js_NudgeOtherContexts(cx);
|
|
|
|
/*
|
|
* Discount all the requests on the current thread from contributing
|
|
* to rt->requestCount before we wait for all other requests to finish.
|
|
* JS_NOTIFY_REQUEST_DONE, which will wake us up, is only called on
|
|
* rt->requestCount transitions to 0.
|
|
*/
|
|
requestDebit = js_CountThreadRequests(cx);
|
|
JS_ASSERT_IF(cx->requestDepth != 0, requestDebit >= 1);
|
|
rt->requestCount -= requestDebit;
|
|
while (rt->requestCount > 0)
|
|
JS_AWAIT_REQUEST_DONE(rt);
|
|
rt->requestCount += requestDebit;
|
|
|
|
#else /* !JS_THREADSAFE */
|
|
|
|
/* Bump gcLevel and return rather than nest; the outer gc will restart. */
|
|
rt->gcLevel++;
|
|
METER_UPDATE_MAX(rt->gcStats.maxlevel, rt->gcLevel);
|
|
if (rt->gcLevel > 1)
|
|
return;
|
|
|
|
#endif /* !JS_THREADSAFE */
|
|
|
|
/*
|
|
* Set rt->gcRunning here within the GC lock, and after waiting for any
|
|
* active requests to end, so that new requests that try to JS_AddRoot,
|
|
* JS_RemoveRoot, or JS_RemoveRootRT block in JS_BeginRequest waiting for
|
|
* rt->gcLevel to drop to zero, while request-less calls to the *Root*
|
|
* APIs block in js_AddRoot or js_RemoveRoot (see above in this file),
|
|
* waiting for GC to finish.
|
|
*/
|
|
rt->gcRunning = JS_TRUE;
|
|
|
|
if (gckind == GC_SET_SLOT_REQUEST) {
|
|
JSSetSlotRequest *ssr;
|
|
|
|
while ((ssr = rt->setSlotRequests) != NULL) {
|
|
rt->setSlotRequests = ssr->next;
|
|
JS_UNLOCK_GC(rt);
|
|
ssr->next = NULL;
|
|
ProcessSetSlotRequest(cx, ssr);
|
|
JS_LOCK_GC(rt);
|
|
}
|
|
|
|
/*
|
|
* We assume here that killing links to parent and prototype objects
|
|
* does not create garbage (such objects typically are long-lived and
|
|
* widely shared, e.g. global objects, Function.prototype, etc.). We
|
|
* collect garbage only if a racing thread attempted GC and is waiting
|
|
* for us to finish (gcLevel > 1) or if someone already poked us.
|
|
*/
|
|
if (rt->gcLevel == 1 && !rt->gcPoke && !rt->gcIsNeeded)
|
|
goto done_running;
|
|
|
|
rt->gcLevel = 0;
|
|
rt->gcPoke = JS_FALSE;
|
|
rt->gcRunning = JS_FALSE;
|
|
#ifdef JS_THREADSAFE
|
|
rt->gcThread = NULL;
|
|
#endif
|
|
gckind = GC_LOCK_HELD;
|
|
goto restart_at_beginning;
|
|
}
|
|
|
|
JS_UNLOCK_GC(rt);
|
|
|
|
#ifdef JS_TRACER
|
|
if (JS_ON_TRACE(cx))
|
|
goto out;
|
|
#endif
|
|
VOUCH_HAVE_STACK();
|
|
|
|
/* Clear gcIsNeeded now, when we are about to start a normal GC cycle. */
|
|
rt->gcIsNeeded = JS_FALSE;
|
|
|
|
/* Reset malloc counter. */
|
|
rt->resetGCMallocBytes();
|
|
|
|
#ifdef JS_DUMP_SCOPE_METERS
|
|
{ extern void js_DumpScopeMeters(JSRuntime *rt);
|
|
js_DumpScopeMeters(rt);
|
|
}
|
|
#endif
|
|
|
|
#ifdef JS_TRACER
|
|
js_PurgeJITOracle();
|
|
#endif
|
|
|
|
restart:
|
|
rt->gcNumber++;
|
|
JS_ASSERT(!rt->gcUnmarkedArenaStackTop);
|
|
JS_ASSERT(rt->gcMarkLaterCount == 0);
|
|
|
|
/*
|
|
* Reset the property cache's type id generator so we can compress ids.
|
|
* Same for the protoHazardShape proxy-shape standing in for all object
|
|
* prototypes having readonly or setter properties.
|
|
*/
|
|
if (rt->shapeGen & SHAPE_OVERFLOW_BIT
|
|
#ifdef JS_GC_ZEAL
|
|
|| rt->gcZeal >= 1
|
|
#endif
|
|
) {
|
|
rt->gcRegenShapes = true;
|
|
rt->gcRegenShapesScopeFlag ^= JSScope::SHAPE_REGEN;
|
|
rt->shapeGen = 0;
|
|
rt->protoHazardShape = 0;
|
|
}
|
|
|
|
js_PurgeThreads(cx);
|
|
#ifdef JS_TRACER
|
|
if (gckind == GC_LAST_CONTEXT) {
|
|
/* Clear builtin functions, which are recreated on demand. */
|
|
memset(rt->builtinFunctions, 0, sizeof rt->builtinFunctions);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Mark phase.
|
|
*/
|
|
JS_TRACER_INIT(&trc, cx, NULL);
|
|
rt->gcMarkingTracer = &trc;
|
|
JS_ASSERT(IS_GC_MARKING_TRACER(&trc));
|
|
|
|
#ifdef DEBUG
|
|
for (a = rt->gcDoubleArenaList.head; a; a = a->prev)
|
|
JS_ASSERT(!a->hasMarkedDoubles);
|
|
#endif
|
|
|
|
js_TraceRuntime(&trc, keepAtoms);
|
|
js_MarkScriptFilenames(rt, keepAtoms);
|
|
|
|
/*
|
|
* Mark children of things that caused too deep recursion during the above
|
|
* tracing.
|
|
*/
|
|
MarkDelayedChildren(&trc);
|
|
|
|
JS_ASSERT(!cx->insideGCMarkCallback);
|
|
if (rt->gcCallback) {
|
|
cx->insideGCMarkCallback = JS_TRUE;
|
|
(void) rt->gcCallback(cx, JSGC_MARK_END);
|
|
JS_ASSERT(cx->insideGCMarkCallback);
|
|
cx->insideGCMarkCallback = JS_FALSE;
|
|
}
|
|
JS_ASSERT(rt->gcMarkLaterCount == 0);
|
|
|
|
rt->gcMarkingTracer = NULL;
|
|
|
|
#ifdef JS_THREADSAFE
|
|
cx->createDeallocatorTask();
|
|
#endif
|
|
|
|
/*
|
|
* Sweep phase.
|
|
*
|
|
* Finalize as we sweep, outside of rt->gcLock but with rt->gcRunning set
|
|
* so that any attempt to allocate a GC-thing from a finalizer will fail,
|
|
* rather than nest badly and leave the unmarked newborn to be swept.
|
|
*
|
|
* We first sweep atom state so we can use js_IsAboutToBeFinalized on
|
|
* JSString or jsdouble held in a hashtable to check if the hashtable
|
|
* entry can be freed. Note that even after the entry is freed, JSObject
|
|
* finalizers can continue to access the corresponding jsdouble* and
|
|
* JSString* assuming that they are unique. This works since the
|
|
* atomization API must not be called during GC.
|
|
*/
|
|
js_SweepAtomState(cx);
|
|
|
|
/* Finalize iterator states before the objects they iterate over. */
|
|
CloseNativeIterators(cx);
|
|
|
|
/* Finalize watch points associated with unreachable objects. */
|
|
js_SweepWatchPoints(cx);
|
|
|
|
#ifdef DEBUG
|
|
/* Save the pre-sweep count of scope-mapped properties. */
|
|
rt->liveScopePropsPreSweep = rt->liveScopeProps;
|
|
#endif
|
|
|
|
/*
|
|
* We finalize JSObject instances before JSString, double and other GC
|
|
* things to ensure that object's finalizer can access them even if they
|
|
* will be freed.
|
|
*
|
|
* To minimize the number of checks per each to be freed object and
|
|
* function we use separated list finalizers when a debug hook is
|
|
* installed.
|
|
*/
|
|
emptyArenas = NULL;
|
|
FinalizeArenaList<JSObject>(cx, FINALIZE_OBJECT, &emptyArenas);
|
|
FinalizeArenaList<JSFunction>(cx, FINALIZE_FUNCTION, &emptyArenas);
|
|
#if JS_HAS_XML_SUPPORT
|
|
FinalizeArenaList<JSXML>(cx, FINALIZE_XML, &emptyArenas);
|
|
#endif
|
|
FinalizeArenaList<JSString>(cx, FINALIZE_STRING, &emptyArenas);
|
|
for (unsigned i = FINALIZE_EXTERNAL_STRING0;
|
|
i <= FINALIZE_EXTERNAL_STRING_LAST;
|
|
++i) {
|
|
FinalizeArenaList<JSString>(cx, i, &emptyArenas);
|
|
}
|
|
|
|
ap = &rt->gcDoubleArenaList.head;
|
|
METER((nlivearenas = 0, nkilledarenas = 0, nthings = 0));
|
|
while ((a = *ap) != NULL) {
|
|
if (!a->hasMarkedDoubles) {
|
|
/* No marked double values in the arena. */
|
|
*ap = a->prev;
|
|
a->prev = emptyArenas;
|
|
emptyArenas = a;
|
|
METER(nkilledarenas++);
|
|
} else {
|
|
a->hasMarkedDoubles = false;
|
|
ap = &a->prev;
|
|
#ifdef JS_GCMETER
|
|
for (size_t i = 0; i != DOUBLES_PER_ARENA; ++i) {
|
|
if (IsMarkedDouble(a, i))
|
|
METER(nthings++);
|
|
}
|
|
METER(nlivearenas++);
|
|
#endif
|
|
}
|
|
}
|
|
METER(UpdateArenaStats(&rt->gcStats.doubleArenaStats,
|
|
nlivearenas, nkilledarenas, nthings));
|
|
rt->gcDoubleArenaList.cursor = rt->gcDoubleArenaList.head;
|
|
|
|
/*
|
|
* Sweep the runtime's property tree after finalizing objects, in case any
|
|
* had watchpoints referencing tree nodes.
|
|
*/
|
|
js_SweepScopeProperties(cx);
|
|
|
|
/*
|
|
* Sweep script filenames after sweeping functions in the generic loop
|
|
* above. In this way when a scripted function's finalizer destroys the
|
|
* script and calls rt->destroyScriptHook, the hook can still access the
|
|
* script's filename. See bug 323267.
|
|
*/
|
|
js_SweepScriptFilenames(rt);
|
|
|
|
/*
|
|
* Destroy arenas after we finished the sweeping so finalizers can safely
|
|
* use js_IsAboutToBeFinalized().
|
|
*/
|
|
DestroyGCArenas(rt, emptyArenas);
|
|
|
|
#ifdef JS_THREADSAFE
|
|
cx->submitDeallocatorTask();
|
|
#endif
|
|
|
|
if (rt->gcCallback)
|
|
(void) rt->gcCallback(cx, JSGC_FINALIZE_END);
|
|
#ifdef DEBUG_srcnotesize
|
|
{ extern void DumpSrcNoteSizeHist();
|
|
DumpSrcNoteSizeHist();
|
|
printf("GC HEAP SIZE %lu\n", (unsigned long)rt->gcBytes);
|
|
}
|
|
#endif
|
|
|
|
#ifdef JS_SCOPE_DEPTH_METER
|
|
{ static FILE *fp;
|
|
if (!fp)
|
|
fp = fopen("/tmp/scopedepth.stats", "w");
|
|
|
|
if (fp) {
|
|
JS_DumpBasicStats(&rt->protoLookupDepthStats, "proto-lookup depth", fp);
|
|
JS_DumpBasicStats(&rt->scopeSearchDepthStats, "scope-search depth", fp);
|
|
JS_DumpBasicStats(&rt->hostenvScopeDepthStats, "hostenv scope depth", fp);
|
|
JS_DumpBasicStats(&rt->lexicalScopeDepthStats, "lexical scope depth", fp);
|
|
|
|
putc('\n', fp);
|
|
fflush(fp);
|
|
}
|
|
}
|
|
#endif /* JS_SCOPE_DEPTH_METER */
|
|
|
|
#ifdef JS_DUMP_LOOP_STATS
|
|
{ static FILE *lsfp;
|
|
if (!lsfp)
|
|
lsfp = fopen("/tmp/loopstats", "w");
|
|
if (lsfp) {
|
|
JS_DumpBasicStats(&rt->loopStats, "loops", lsfp);
|
|
fflush(lsfp);
|
|
}
|
|
}
|
|
#endif /* JS_DUMP_LOOP_STATS */
|
|
|
|
#ifdef JS_TRACER
|
|
out:
|
|
#endif
|
|
JS_LOCK_GC(rt);
|
|
|
|
/*
|
|
* We want to restart GC if js_GC was called recursively or if any of the
|
|
* finalizers called js_RemoveRoot or js_UnlockGCThingRT.
|
|
*/
|
|
if (!JS_ON_TRACE(cx) && (rt->gcLevel > 1 || rt->gcPoke)) {
|
|
VOUCH_HAVE_STACK();
|
|
rt->gcLevel = 1;
|
|
rt->gcPoke = JS_FALSE;
|
|
JS_UNLOCK_GC(rt);
|
|
goto restart;
|
|
}
|
|
|
|
rt->setGCLastBytes(rt->gcBytes);
|
|
done_running:
|
|
rt->gcLevel = 0;
|
|
rt->gcRunning = rt->gcRegenShapes = false;
|
|
|
|
#ifdef JS_THREADSAFE
|
|
rt->gcThread = NULL;
|
|
JS_NOTIFY_GC_DONE(rt);
|
|
|
|
/*
|
|
* Unlock unless we have GC_LOCK_HELD which requires locked GC on return.
|
|
*/
|
|
if (!(gckind & GC_LOCK_HELD))
|
|
JS_UNLOCK_GC(rt);
|
|
#endif
|
|
|
|
/*
|
|
* Execute JSGC_END callback outside the lock. Again, sample the callback
|
|
* pointer in case it changes, since we are outside of the GC vs. requests
|
|
* interlock mechanism here.
|
|
*/
|
|
if (gckind != GC_SET_SLOT_REQUEST && (callback = rt->gcCallback)) {
|
|
JSWeakRoots savedWeakRoots;
|
|
JSTempValueRooter tvr;
|
|
|
|
if (gckind & GC_KEEP_ATOMS) {
|
|
/*
|
|
* We allow JSGC_END implementation to force a full GC or allocate
|
|
* new GC things. Thus we must protect the weak roots from garbage
|
|
* collection and overwrites.
|
|
*/
|
|
savedWeakRoots = cx->weakRoots;
|
|
JS_PUSH_TEMP_ROOT_WEAK_COPY(cx, &savedWeakRoots, &tvr);
|
|
JS_KEEP_ATOMS(rt);
|
|
JS_UNLOCK_GC(rt);
|
|
}
|
|
|
|
(void) callback(cx, JSGC_END);
|
|
|
|
if (gckind & GC_KEEP_ATOMS) {
|
|
JS_LOCK_GC(rt);
|
|
JS_UNKEEP_ATOMS(rt);
|
|
JS_POP_TEMP_ROOT(cx, &tvr);
|
|
} else if (gckind == GC_LAST_CONTEXT && rt->gcPoke) {
|
|
/*
|
|
* On shutdown iterate until JSGC_END callback stops creating
|
|
* garbage.
|
|
*/
|
|
goto restart_at_beginning;
|
|
}
|
|
}
|
|
}
|