LCOV - app.info - js/src/ds/LifoAlloc.cpp

LCOV - code coverage report
| Current view: | directory - js/src/ds - LifoAlloc.cpp (source / functions) |  | Found | Hit | Coverage |
| Test: | app.info | Lines: | 65 | 56 | 86.2 %
| Date: | 2012-04-07 | Functions: | 6 | 6 | 100.0 %

           1                 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
           2                 :  * vim: set ts=8 sw=4 et tw=99 ft=cpp:
           3                 :  *
           4                 :  * ***** BEGIN LICENSE BLOCK *****
           5                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
           6                 :  *
           7                 :  * The contents of this file are subject to the Mozilla Public License Version
           8                 :  * 1.1 (the "License"); you may not use this file except in compliance with
           9                 :  * the License. You may obtain a copy of the License at
          10                 :  * http://www.mozilla.org/MPL/
          11                 :  *
          12                 :  * Software distributed under the License is distributed on an "AS IS" basis,
          13                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
          14                 :  * for the specific language governing rights and limitations under the
          15                 :  * License.
          16                 :  *
          17                 :  * The Original Code is Mozilla SpiderMonkey JavaScript code.
          18                 :  *
          19                 :  * The Initial Developer of the Original Code is
          20                 :  * the Mozilla Foundation.
          21                 :  * Portions created by the Initial Developer are Copyright (C) 2011
          22                 :  * the Initial Developer. All Rights Reserved.
          23                 :  *
          24                 :  * Contributor(s):
          25                 :  *  Chris Leary <cdleary@mozilla.com>
          26                 :  *
          27                 :  * Alternatively, the contents of this file may be used under the terms of
          28                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
          29                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
          30                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
          31                 :  * of those above. If you wish to allow use of your version of this file only
          32                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
          33                 :  * use your version of this file under the terms of the MPL, indicate your
          34                 :  * decision by deleting the provisions above and replace them with the notice
          35                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
          36                 :  * the provisions above, a recipient may use your version of this file under
          37                 :  * the terms of any one of the MPL, the GPL or the LGPL.
          38                 :  *
          39                 :  * ***** END LICENSE BLOCK ***** */
          40                 :
          41                 : #include "LifoAlloc.h"
          42                 :
          43                 : #include <new>
          44                 :
          45                 : using namespace js;
          46                 :
          47                 : namespace js {
          48                 : namespace detail {
          49                 :
          50                 : BumpChunk *
          51           93652 : BumpChunk::new_(size_t chunkSize)
          52                 : {
          53           93652 :     JS_ASSERT(RoundUpPow2(chunkSize) == chunkSize);
          54           93652 :     void *mem = js_malloc(chunkSize);
          55           93652 :     if (!mem)
          56               0 :         return NULL;
          57           93652 :     BumpChunk *result = new (mem) BumpChunk(chunkSize - sizeof(BumpChunk));
          58                 :
          59                 :     /*
          60                 :      * We assume that the alignment of sAlign is less than that of
          61                 :      * the underlying memory allocator -- creating a new BumpChunk should
          62                 :      * always satisfy the sAlign alignment constraint.
          63                 :      */
          64           93652 :     JS_ASSERT(AlignPtr(result->bump) == result->bump);
          65           93652 :     return result;
          66                 : }
          67                 :
          68                 : void
          69           93652 : BumpChunk::delete_(BumpChunk *chunk)
          70                 : {
          71                 : #ifdef DEBUG
          72           93652 :         memset(chunk, 0xcd, sizeof(*chunk) + chunk->bumpSpaceSize);
          73                 : #endif
          74           93652 :         js_free(chunk);
          75           93652 : }
          76                 :
          77                 : bool
          78        32198691 : BumpChunk::canAlloc(size_t n)
          79                 : {
          80        32198691 :     char *aligned = AlignPtr(bump);
          81        32198691 :     char *bumped = aligned + n;
          82        32198691 :     return bumped <= limit && bumped > headerBase();
          83                 : }
          84                 :
          85                 : } /* namespace detail */
          86                 : } /* namespace js */
          87                 :
          88                 : void
          89          176541 : LifoAlloc::freeAll()
          90                 : {
          91          446734 :     while (first) {
          92           93652 :         BumpChunk *victim = first;
          93           93652 :         first = first->next();
          94           93652 :         BumpChunk::delete_(victim);
          95                 :     }
          96          176541 :     first = latest = NULL;
          97          176541 : }
          98                 :
          99                 : void
         100           39964 : LifoAlloc::freeUnused()
         101                 : {
         102                 :     /* Don't free anything if we have outstanding marks. */
         103           39964 :     if (markCount || !first)
         104           20293 :         return;
         105                 :
         106           19671 :     JS_ASSERT(first && latest);
         107                 :
         108                 :     /* Rewind through any unused chunks. */
         109           19671 :     if (!latest->used()) {
         110           19662 :         BumpChunk *lastUsed = NULL;
         111           19662 :         for (BumpChunk *it = first; it != latest; it = it->next()) {
         112               0 :             if (it->used())
         113               0 :                 lastUsed = it;
         114                 :         }
         115           19662 :         if (!lastUsed) {
         116           19662 :             freeAll();
         117           19662 :             return;
         118                 :         }
         119               0 :         latest = lastUsed;
         120                 :     }
         121                 :
         122                 :     /* Free all chunks after |latest|. */
         123               9 :     BumpChunk *it = latest->next();
         124              18 :     while (it) {
         125               0 :         BumpChunk *victim = it;
         126               0 :         it = it->next();
         127               0 :         BumpChunk::delete_(victim);
         128                 :     }
         129                 :
         130               9 :     latest->setNext(NULL);
         131                 : }
         132                 :
         133                 : LifoAlloc::BumpChunk *
         134          116962 : LifoAlloc::getOrCreateChunk(size_t n)
         135                 : {
         136          116962 :     if (first) {
         137                 :         /* Look for existing, unused BumpChunks to satisfy the request. */
         138          113962 :         while (latest->next()) {
         139           23310 :             latest = latest->next();
         140           23310 :             latest->resetBump(); /* This was an unused BumpChunk on the chain. */
         141           23310 :             if (latest->canAlloc(n))
         142           23310 :                 return latest;
         143                 :         }
         144                 :     }
         145                 :
         146           93652 :     size_t defaultChunkFreeSpace = defaultChunkSize_ - sizeof(BumpChunk);
         147                 :     size_t chunkSize;
         148           93652 :     if (n > defaultChunkFreeSpace) {
         149             135 :         size_t allocSizeWithHeader = n + sizeof(BumpChunk);
         150                 :
         151                 :         /* Guard for overflow. */
         152             135 :         if (allocSizeWithHeader < n ||
         153                 :             (allocSizeWithHeader & (size_t(1) << (tl::BitSize<size_t>::result - 1)))) {
         154               0 :             return NULL;
         155                 :         }
         156                 :
         157             135 :         chunkSize = RoundUpPow2(allocSizeWithHeader);
         158                 :     } else {
         159           93517 :         chunkSize = defaultChunkSize_;
         160                 :     }
         161                 :
         162                 :     /* If we get here, we couldn't find an existing BumpChunk to fill the request. */
         163           93652 :     BumpChunk *newChunk = BumpChunk::new_(chunkSize);
         164           93652 :     if (!newChunk)
         165               0 :         return NULL;
         166           93652 :     if (!first) {
         167           59981 :         latest = first = newChunk;
         168                 :     } else {
         169           33671 :         JS_ASSERT(latest && !latest->next());
         170           33671 :         latest->setNext(newChunk);
         171           33671 :         latest = newChunk;
         172                 :     }
         173           93652 :     return newChunk;
         174                 : }

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