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 #include "ExecutableAllocator.h"
  28
  29 #include "JSCInlines.h"
  30
  31 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  32 #include "CodeProfiling.h"
  33 #include <wtf/HashSet.h>
  34 #include <wtf/MetaAllocator.h>
  35 #include <wtf/NeverDestroyed.h>
  36 #include <wtf/PageReservation.h>
  37 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
  38 #include <wtf/PassOwnPtr.h>
  39 #endif
  40 #include <wtf/ThreadingPrimitives.h>
  41 #include <wtf/VMTags.h>
  42 #endif
  43
  44 // Uncomment to create an artificial executable memory usage limit. This limit
  45 // is imperfect and is primarily useful for testing the VM's ability to handle
  46 // out-of-executable-memory situations.
  47 // #define EXECUTABLE_MEMORY_LIMIT 1000000
  48
  49 #if ENABLE(ASSEMBLER)
  50
  51 using namespace WTF;
  52
  53 namespace JSC {
  54
  55 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  56
  57 class DemandExecutableAllocator : public MetaAllocator {
  58 public:
  59     DemandExecutableAllocator()
  60         : MetaAllocator(jitAllocationGranule)
  61     {
  62         std::lock_guard<std::mutex> lock(allocatorsMutex());
  63         allocators().add(this);
  64         // Don't preallocate any memory here.
  65     }
  66
  67     virtual ~DemandExecutableAllocator()
  68     {
  69         {
  70             std::lock_guard<std::mutex> lock(allocatorsMutex());
  71             allocators().remove(this);
  72         }
  73         for (unsigned i = 0; i < reservations.size(); ++i)
  74             reservations.at(i).deallocate();
  75     }
  76
  77     static size_t bytesAllocatedByAllAllocators()
  78     {
  79         size_t total = 0;
  80         std::lock_guard<std::mutex> lock(allocatorsMutex());
  81         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  82             total += (*allocator)->bytesAllocated();
  83         return total;
  84     }
  85
  86     static size_t bytesCommittedByAllocactors()
  87     {
  88         size_t total = 0;
  89         std::lock_guard<std::mutex> lock(allocatorsMutex());
  90         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  91             total += (*allocator)->bytesCommitted();
  92         return total;
  93     }
  94
  95 #if ENABLE(META_ALLOCATOR_PROFILE)
  96     static void dumpProfileFromAllAllocators()
  97     {
  98         std::lock_guard<std::mutex> lock(allocatorsMutex());
  99         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
 100             (*allocator)->dumpProfile();
 101     }
 102 #endif
 103
 104 protected:
 105     virtual void* allocateNewSpace(size_t& numPages)
 106     {
 107         size_t newNumPages = (((numPages * pageSize() + JIT_ALLOCATOR_LARGE_ALLOC_SIZE - 1) / JIT_ALLOCATOR_LARGE_ALLOC_SIZE * JIT_ALLOCATOR_LARGE_ALLOC_SIZE) + pageSize() - 1) / pageSize();
 108
 109         ASSERT(newNumPages >= numPages);
 110
 111         numPages = newNumPages;
 112
 113 #ifdef EXECUTABLE_MEMORY_LIMIT
 114         if (bytesAllocatedByAllAllocators() >= EXECUTABLE_MEMORY_LIMIT)
 115             return 0;
 116 #endif
 117
 118         PageReservation reservation = PageReservation::reserve(numPages * pageSize(), OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
 119         RELEASE_ASSERT(reservation);
 120
 121         reservations.append(reservation);
 122
 123         return reservation.base();
 124     }
 125
 126     virtual void notifyNeedPage(void* page)
 127     {
 128         OSAllocator::commit(page, pageSize(), EXECUTABLE_POOL_WRITABLE, true);
 129     }
 130
 131     virtual void notifyPageIsFree(void* page)
 132     {
 133         OSAllocator::decommit(page, pageSize());
 134     }
 135
 136 private:
 137     Vector<PageReservation, 16> reservations;
 138     static HashSet<DemandExecutableAllocator*>& allocators()
 139     {
 140         DEPRECATED_DEFINE_STATIC_LOCAL(HashSet<DemandExecutableAllocator*>, sAllocators, ());
 141         return sAllocators;
 142     }
 143
 144     static std::mutex& allocatorsMutex()
 145     {
 146         static NeverDestroyed<std::mutex> mutex;
 147
 148         return mutex;
 149     }
 150 };
 151
 152 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 153 void ExecutableAllocator::initializeAllocator()
 154 {
 155 }
 156 #else
 157 static DemandExecutableAllocator* gAllocator;
 158
 159 namespace {
 160 static inline DemandExecutableAllocator* allocator()
 161 {
 162     return gAllocator;
 163 }
 164 }
 165
 166 void ExecutableAllocator::initializeAllocator()
 167 {
 168     ASSERT(!gAllocator);
 169     gAllocator = new DemandExecutableAllocator();
 170     CodeProfiling::notifyAllocator(gAllocator);
 171 }
 172 #endif
 173
 174 ExecutableAllocator::ExecutableAllocator(VM&)
 175 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 176     : m_allocator(adoptPtr(new  DemandExecutableAllocator()))
 177 #endif
 178 {
 179     ASSERT(allocator());
 180 }
 181
 182 ExecutableAllocator::~ExecutableAllocator()
 183 {
 184 }
 185
 186 bool ExecutableAllocator::isValid() const
 187 {
 188     return true;
 189 }
 190
 191 bool ExecutableAllocator::underMemoryPressure()
 192 {
 193 #ifdef EXECUTABLE_MEMORY_LIMIT
 194     return DemandExecutableAllocator::bytesAllocatedByAllAllocators() > EXECUTABLE_MEMORY_LIMIT / 2;
 195 #else
 196     return false;
 197 #endif
 198 }
 199
 200 double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
 201 {
 202     double result;
 203 #ifdef EXECUTABLE_MEMORY_LIMIT
 204     size_t bytesAllocated = DemandExecutableAllocator::bytesAllocatedByAllAllocators() + addedMemoryUsage;
 205     if (bytesAllocated >= EXECUTABLE_MEMORY_LIMIT)
 206         bytesAllocated = EXECUTABLE_MEMORY_LIMIT;
 207     result = static_cast<double>(EXECUTABLE_MEMORY_LIMIT) /
 208         (EXECUTABLE_MEMORY_LIMIT - bytesAllocated);
 209 #else
 210     UNUSED_PARAM(addedMemoryUsage);
 211     result = 1.0;
 212 #endif
 213     if (result < 1.0)
 214         result = 1.0;
 215     return result;
 216
 217 }
 218
 219 PassRefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(VM&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
 220 {
 221     RefPtr<ExecutableMemoryHandle> result = allocator()->allocate(sizeInBytes, ownerUID);
 222     RELEASE_ASSERT(result || effort != JITCompilationMustSucceed);
 223     return result.release();
 224 }
 225
 226 size_t ExecutableAllocator::committedByteCount()
 227 {
 228     return DemandExecutableAllocator::bytesCommittedByAllocactors();
 229 }
 230
 231 #if ENABLE(META_ALLOCATOR_PROFILE)
 232 void ExecutableAllocator::dumpProfile()
 233 {
 234     DemandExecutableAllocator::dumpProfileFromAllAllocators();
 235 }
 236 #endif
 237
 238 #endif // ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
 239
 240 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 241
 242 #if OS(WINDOWS)
 243 #error "ASSEMBLER_WX_EXCLUSIVE not yet suported on this platform."
 244 #endif
 245
 246 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
 247 {
 248     size_t pageSize = WTF::pageSize();
 249
 250     // Calculate the start of the page containing this region,
 251     // and account for this extra memory within size.
 252     intptr_t startPtr = reinterpret_cast<intptr_t>(start);
 253     intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
 254     void* pageStart = reinterpret_cast<void*>(pageStartPtr);
 255     size += (startPtr - pageStartPtr);
 256
 257     // Round size up
 258     size += (pageSize - 1);
 259     size &= ~(pageSize - 1);
 260
 261     mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
 262 }
 263
 264 #endif
 265
 266 }
 267
 268 #endif // HAVE(ASSEMBLER)