jit/ExecutableAllocator.cpp

   1 /*
   2  * Copyright (C) 2008 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27
  28 #include "ExecutableAllocator.h"
  29
  30 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  31 #include "CodeProfiling.h"
  32 #include <wtf/HashSet.h>
  33 #include <wtf/MetaAllocator.h>
  34 #include <wtf/PageReservation.h>
  35 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
  36 #include <wtf/PassOwnPtr.h>
  37 #endif
  38 #include <wtf/ThreadingPrimitives.h>
  39 #include <wtf/VMTags.h>
  40 #endif
  41
  42 // Uncomment to create an artificial executable memory usage limit. This limit
  43 // is imperfect and is primarily useful for testing the VM's ability to handle
  44 // out-of-executable-memory situations.
  45 // #define EXECUTABLE_MEMORY_LIMIT 1000000
  46
  47 #if ENABLE(ASSEMBLER)
  48
  49 using namespace WTF;
  50
  51 namespace JSC {
  52
  53 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  54
  55 class DemandExecutableAllocator : public MetaAllocator {
  56 public:
  57     DemandExecutableAllocator()
  58         : MetaAllocator(32) // round up all allocations to 32 bytes
  59     {
  60         MutexLocker lock(allocatorsMutex());
  61         allocators().add(this);
  62         // Don't preallocate any memory here.
  63     }
  64
  65     virtual ~DemandExecutableAllocator()
  66     {
  67         {
  68             MutexLocker lock(allocatorsMutex());
  69             allocators().remove(this);
  70         }
  71         for (unsigned i = 0; i < reservations.size(); ++i)
  72             reservations.at(i).deallocate();
  73     }
  74
  75     static size_t bytesAllocatedByAllAllocators()
  76     {
  77         size_t total = 0;
  78         MutexLocker lock(allocatorsMutex());
  79         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  80             total += (*allocator)->bytesAllocated();
  81         return total;
  82     }
  83
  84     static size_t bytesCommittedByAllocactors()
  85     {
  86         size_t total = 0;
  87         MutexLocker lock(allocatorsMutex());
  88         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  89             total += (*allocator)->bytesCommitted();
  90         return total;
  91     }
  92
  93 #if ENABLE(META_ALLOCATOR_PROFILE)
  94     static void dumpProfileFromAllAllocators()
  95     {
  96         MutexLocker lock(allocatorsMutex());
  97         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  98             (*allocator)->dumpProfile();
  99     }
 100 #endif
 101
 102 protected:
 103     virtual void* allocateNewSpace(size_t& numPages)
 104     {
 105         size_t newNumPages = (((numPages * pageSize() + JIT_ALLOCATOR_LARGE_ALLOC_SIZE - 1) / JIT_ALLOCATOR_LARGE_ALLOC_SIZE * JIT_ALLOCATOR_LARGE_ALLOC_SIZE) + pageSize() - 1) / pageSize();
 106
 107         ASSERT(newNumPages >= numPages);
 108
 109         numPages = newNumPages;
 110
 111 #ifdef EXECUTABLE_MEMORY_LIMIT
 112         if (bytesAllocatedByAllAllocators() >= EXECUTABLE_MEMORY_LIMIT)
 113             return 0;
 114 #endif
 115
 116         PageReservation reservation = PageReservation::reserve(numPages * pageSize(), OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
 117         if (!reservation)
 118             CRASH();
 119
 120         reservations.append(reservation);
 121
 122         return reservation.base();
 123     }
 124
 125     virtual void notifyNeedPage(void* page)
 126     {
 127         OSAllocator::commit(page, pageSize(), EXECUTABLE_POOL_WRITABLE, true);
 128     }
 129
 130     virtual void notifyPageIsFree(void* page)
 131     {
 132         OSAllocator::decommit(page, pageSize());
 133     }
 134
 135 private:
 136     Vector<PageReservation, 16> reservations;
 137     static HashSet<DemandExecutableAllocator*>& allocators()
 138     {
 139         DEFINE_STATIC_LOCAL(HashSet<DemandExecutableAllocator*>, sAllocators, ());
 140         return sAllocators;
 141     }
 142     static Mutex& allocatorsMutex()
 143     {
 144         DEFINE_STATIC_LOCAL(Mutex, mutex, ());
 145         return mutex;
 146     }
 147 };
 148
 149 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 150 void ExecutableAllocator::initializeAllocator()
 151 {
 152 }
 153 #else
 154 static DemandExecutableAllocator* gAllocator;
 155
 156 namespace {
 157 static inline DemandExecutableAllocator* allocator()
 158 {
 159     return gAllocator;
 160 }
 161 }
 162
 163 void ExecutableAllocator::initializeAllocator()
 164 {
 165     ASSERT(!gAllocator);
 166     gAllocator = new DemandExecutableAllocator();
 167     CodeProfiling::notifyAllocator(gAllocator);
 168 }
 169 #endif
 170
 171 ExecutableAllocator::ExecutableAllocator(JSGlobalData&)
 172 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 173     : m_allocator(adoptPtr(new  DemandExecutableAllocator()))
 174 #endif
 175 {
 176     ASSERT(allocator());
 177 }
 178
 179 ExecutableAllocator::~ExecutableAllocator()
 180 {
 181 }
 182
 183 bool ExecutableAllocator::isValid() const
 184 {
 185     return true;
 186 }
 187
 188 bool ExecutableAllocator::underMemoryPressure()
 189 {
 190 #ifdef EXECUTABLE_MEMORY_LIMIT
 191     return DemandExecutableAllocator::bytesAllocatedByAllAllocators() > EXECUTABLE_MEMORY_LIMIT / 2;
 192 #else
 193     return false;
 194 #endif
 195 }
 196
 197 double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
 198 {
 199     double result;
 200 #ifdef EXECUTABLE_MEMORY_LIMIT
 201     size_t bytesAllocated = DemandExecutableAllocator::bytesAllocatedByAllAllocators() + addedMemoryUsage;
 202     if (bytesAllocated >= EXECUTABLE_MEMORY_LIMIT)
 203         bytesAllocated = EXECUTABLE_MEMORY_LIMIT;
 204     result = static_cast<double>(EXECUTABLE_MEMORY_LIMIT) /
 205         (EXECUTABLE_MEMORY_LIMIT - bytesAllocated);
 206 #else
 207     UNUSED_PARAM(addedMemoryUsage);
 208     result = 1.0;
 209 #endif
 210     if (result < 1.0)
 211         result = 1.0;
 212     return result;
 213
 214 }
 215
 216 PassRefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(JSGlobalData&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
 217 {
 218     RefPtr<ExecutableMemoryHandle> result = allocator()->allocate(sizeInBytes, ownerUID);
 219     if (!result && effort == JITCompilationMustSucceed)
 220         CRASH();
 221     return result.release();
 222 }
 223
 224 size_t ExecutableAllocator::committedByteCount()
 225 {
 226     return DemandExecutableAllocator::bytesCommittedByAllocactors();
 227 }
 228
 229 #if ENABLE(META_ALLOCATOR_PROFILE)
 230 void ExecutableAllocator::dumpProfile()
 231 {
 232     DemandExecutableAllocator::dumpProfileFromAllAllocators();
 233 }
 234 #endif
 235
 236 #endif // ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
 237
 238 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 239
 240 #if OS(WINDOWS)
 241 #error "ASSEMBLER_WX_EXCLUSIVE not yet suported on this platform."
 242 #endif
 243
 244 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
 245 {
 246     size_t pageSize = WTF::pageSize();
 247
 248     // Calculate the start of the page containing this region,
 249     // and account for this extra memory within size.
 250     intptr_t startPtr = reinterpret_cast<intptr_t>(start);
 251     intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
 252     void* pageStart = reinterpret_cast<void*>(pageStartPtr);
 253     size += (startPtr - pageStartPtr);
 254
 255     // Round size up
 256     size += (pageSize - 1);
 257     size &= ~(pageSize - 1);
 258
 259     mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
 260 }
 261
 262 #endif
 263
 264 }
 265
 266 #endif // HAVE(ASSEMBLER)