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 #include <wtf/ThreadingPrimitives.h>
  38 #include <wtf/VMTags.h>
  39 #endif
  40
  41 // Uncomment to create an artificial executable memory usage limit. This limit
  42 // is imperfect and is primarily useful for testing the VM's ability to handle
  43 // out-of-executable-memory situations.
  44 // #define EXECUTABLE_MEMORY_LIMIT 1000000
  45
  46 #if ENABLE(ASSEMBLER)
  47
  48 using namespace WTF;
  49
  50 namespace JSC {
  51
  52 #if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
  53
  54 class DemandExecutableAllocator : public MetaAllocator {
  55 public:
  56     DemandExecutableAllocator()
  57         : MetaAllocator(jitAllocationGranule)
  58     {
  59         std::lock_guard<std::mutex> lock(allocatorsMutex());
  60         allocators().add(this);
  61         // Don't preallocate any memory here.
  62     }
  63
  64     virtual ~DemandExecutableAllocator()
  65     {
  66         {
  67             std::lock_guard<std::mutex> lock(allocatorsMutex());
  68             allocators().remove(this);
  69         }
  70         for (unsigned i = 0; i < reservations.size(); ++i)
  71             reservations.at(i).deallocate();
  72     }
  73
  74     static size_t bytesAllocatedByAllAllocators()
  75     {
  76         size_t total = 0;
  77         std::lock_guard<std::mutex> lock(allocatorsMutex());
  78         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  79             total += (*allocator)->bytesAllocated();
  80         return total;
  81     }
  82
  83     static size_t bytesCommittedByAllocactors()
  84     {
  85         size_t total = 0;
  86         std::lock_guard<std::mutex> lock(allocatorsMutex());
  87         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  88             total += (*allocator)->bytesCommitted();
  89         return total;
  90     }
  91
  92 #if ENABLE(META_ALLOCATOR_PROFILE)
  93     static void dumpProfileFromAllAllocators()
  94     {
  95         std::lock_guard<std::mutex> lock(allocatorsMutex());
  96         for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
  97             (*allocator)->dumpProfile();
  98     }
  99 #endif
 100
 101 protected:
 102     virtual void* allocateNewSpace(size_t& numPages)
 103     {
 104         size_t newNumPages = (((numPages * pageSize() + JIT_ALLOCATOR_LARGE_ALLOC_SIZE - 1) / JIT_ALLOCATOR_LARGE_ALLOC_SIZE * JIT_ALLOCATOR_LARGE_ALLOC_SIZE) + pageSize() - 1) / pageSize();
 105
 106         ASSERT(newNumPages >= numPages);
 107
 108         numPages = newNumPages;
 109
 110 #ifdef EXECUTABLE_MEMORY_LIMIT
 111         if (bytesAllocatedByAllAllocators() >= EXECUTABLE_MEMORY_LIMIT)
 112             return 0;
 113 #endif
 114
 115         PageReservation reservation = PageReservation::reserve(numPages * pageSize(), OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
 116         RELEASE_ASSERT(reservation);
 117
 118         reservations.append(reservation);
 119
 120         return reservation.base();
 121     }
 122
 123     virtual void notifyNeedPage(void* page)
 124     {
 125         OSAllocator::commit(page, pageSize(), EXECUTABLE_POOL_WRITABLE, true);
 126     }
 127
 128     virtual void notifyPageIsFree(void* page)
 129     {
 130         OSAllocator::decommit(page, pageSize());
 131     }
 132
 133 private:
 134     Vector<PageReservation, 16> reservations;
 135     static HashSet<DemandExecutableAllocator*>& allocators()
 136     {
 137         DEPRECATED_DEFINE_STATIC_LOCAL(HashSet<DemandExecutableAllocator*>, sAllocators, ());
 138         return sAllocators;
 139     }
 140
 141     static std::mutex& allocatorsMutex()
 142     {
 143         static NeverDestroyed<std::mutex> mutex;
 144
 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(VM&)
 172 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 173     : m_allocator(std::make_unique<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 RefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(VM&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
 217 {
 218     RefPtr<ExecutableMemoryHandle> result = allocator()->allocate(sizeInBytes, ownerUID);
 219     RELEASE_ASSERT(result || effort != JITCompilationMustSucceed);
 220     return result;
 221 }
 222
 223 size_t ExecutableAllocator::committedByteCount()
 224 {
 225     return DemandExecutableAllocator::bytesCommittedByAllocactors();
 226 }
 227
 228 #if ENABLE(META_ALLOCATOR_PROFILE)
 229 void ExecutableAllocator::dumpProfile()
 230 {
 231     DemandExecutableAllocator::dumpProfileFromAllAllocators();
 232 }
 233 #endif
 234
 235 #endif // ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
 236
 237 #if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
 238
 239 #if OS(WINDOWS)
 240 #error "ASSEMBLER_WX_EXCLUSIVE not yet suported on this platform."
 241 #endif
 242
 243 void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
 244 {
 245     size_t pageSize = WTF::pageSize();
 246
 247     // Calculate the start of the page containing this region,
 248     // and account for this extra memory within size.
 249     intptr_t startPtr = reinterpret_cast<intptr_t>(start);
 250     intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
 251     void* pageStart = reinterpret_cast<void*>(pageStartPtr);
 252     size += (startPtr - pageStartPtr);
 253
 254     // Round size up
 255     size += (pageSize - 1);
 256     size &= ~(pageSize - 1);
 257
 258     mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
 259 }
 260
 261 #endif
 262
 263 }
 264
 265 #endif // HAVE(ASSEMBLER)