X-Git-Url: https://git.saurik.com/apple/javascriptcore.git/blobdiff_plain/9dae56ea45a0f5f8136a5c93d6f3a7f99399ca73..ed1e77d3adeb83d26fd1dfb16dd84cabdcefd250:/jit/ExecutableAllocator.cpp?ds=sidebyside

diff --git a/jit/ExecutableAllocator.cpp b/jit/ExecutableAllocator.cpp
index f6b27ec..bb49e73 100644
--- a/jit/ExecutableAllocator.cpp
+++ b/jit/ExecutableAllocator.cpp
@@ -24,14 +24,241 @@
  */
 
 #include "config.h"
-
 #include "ExecutableAllocator.h"
 
+#include "JSCInlines.h"
+
+#if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
+#include "CodeProfiling.h"
+#include <wtf/HashSet.h>
+#include <wtf/MetaAllocator.h>
+#include <wtf/NeverDestroyed.h>
+#include <wtf/PageReservation.h>
+#include <wtf/ThreadingPrimitives.h>
+#include <wtf/VMTags.h>
+#endif
+
+// Uncomment to create an artificial executable memory usage limit. This limit
+// is imperfect and is primarily useful for testing the VM's ability to handle
+// out-of-executable-memory situations.
+// #define EXECUTABLE_MEMORY_LIMIT 1000000
+
 #if ENABLE(ASSEMBLER)
 
+using namespace WTF;
+
 namespace JSC {
 
-size_t ExecutableAllocator::pageSize = 0;
+#if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
+
+class DemandExecutableAllocator : public MetaAllocator {
+public:
+    DemandExecutableAllocator()
+        : MetaAllocator(jitAllocationGranule)
+    {
+        std::lock_guard<std::mutex> lock(allocatorsMutex());
+        allocators().add(this);
+        // Don't preallocate any memory here.
+    }
+    
+    virtual ~DemandExecutableAllocator()
+    {
+        {
+            std::lock_guard<std::mutex> lock(allocatorsMutex());
+            allocators().remove(this);
+        }
+        for (unsigned i = 0; i < reservations.size(); ++i)
+            reservations.at(i).deallocate();
+    }
+
+    static size_t bytesAllocatedByAllAllocators()
+    {
+        size_t total = 0;
+        std::lock_guard<std::mutex> lock(allocatorsMutex());
+        for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
+            total += (*allocator)->bytesAllocated();
+        return total;
+    }
+
+    static size_t bytesCommittedByAllocactors()
+    {
+        size_t total = 0;
+        std::lock_guard<std::mutex> lock(allocatorsMutex());
+        for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
+            total += (*allocator)->bytesCommitted();
+        return total;
+    }
+
+#if ENABLE(META_ALLOCATOR_PROFILE)
+    static void dumpProfileFromAllAllocators()
+    {
+        std::lock_guard<std::mutex> lock(allocatorsMutex());
+        for (HashSet<DemandExecutableAllocator*>::const_iterator allocator = allocators().begin(); allocator != allocators().end(); ++allocator)
+            (*allocator)->dumpProfile();
+    }
+#endif
+
+protected:
+    virtual void* allocateNewSpace(size_t& numPages)
+    {
+        size_t newNumPages = (((numPages * pageSize() + JIT_ALLOCATOR_LARGE_ALLOC_SIZE - 1) / JIT_ALLOCATOR_LARGE_ALLOC_SIZE * JIT_ALLOCATOR_LARGE_ALLOC_SIZE) + pageSize() - 1) / pageSize();
+        
+        ASSERT(newNumPages >= numPages);
+        
+        numPages = newNumPages;
+        
+#ifdef EXECUTABLE_MEMORY_LIMIT
+        if (bytesAllocatedByAllAllocators() >= EXECUTABLE_MEMORY_LIMIT)
+            return 0;
+#endif
+        
+        PageReservation reservation = PageReservation::reserve(numPages * pageSize(), OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
+        RELEASE_ASSERT(reservation);
+        
+        reservations.append(reservation);
+        
+        return reservation.base();
+    }
+    
+    virtual void notifyNeedPage(void* page)
+    {
+        OSAllocator::commit(page, pageSize(), EXECUTABLE_POOL_WRITABLE, true);
+    }
+    
+    virtual void notifyPageIsFree(void* page)
+    {
+        OSAllocator::decommit(page, pageSize());
+    }
+
+private:
+    Vector<PageReservation, 16> reservations;
+    static HashSet<DemandExecutableAllocator*>& allocators()
+    {
+        DEPRECATED_DEFINE_STATIC_LOCAL(HashSet<DemandExecutableAllocator*>, sAllocators, ());
+        return sAllocators;
+    }
+
+    static std::mutex& allocatorsMutex()
+    {
+        static NeverDestroyed<std::mutex> mutex;
+
+        return mutex;
+    }
+};
+
+#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
+void ExecutableAllocator::initializeAllocator()
+{
+}
+#else
+static DemandExecutableAllocator* gAllocator;
+
+namespace {
+static inline DemandExecutableAllocator* allocator()
+{
+    return gAllocator;
+}
+}
+
+void ExecutableAllocator::initializeAllocator()
+{
+    ASSERT(!gAllocator);
+    gAllocator = new DemandExecutableAllocator();
+    CodeProfiling::notifyAllocator(gAllocator);
+}
+#endif
+
+ExecutableAllocator::ExecutableAllocator(VM&)
+#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
+    : m_allocator(std::make_unique<DemandExecutableAllocator>())
+#endif
+{
+    ASSERT(allocator());
+}
+
+ExecutableAllocator::~ExecutableAllocator()
+{
+}
+
+bool ExecutableAllocator::isValid() const
+{
+    return true;
+}
+
+bool ExecutableAllocator::underMemoryPressure()
+{
+#ifdef EXECUTABLE_MEMORY_LIMIT
+    return DemandExecutableAllocator::bytesAllocatedByAllAllocators() > EXECUTABLE_MEMORY_LIMIT / 2;
+#else
+    return false;
+#endif
+}
+
+double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
+{
+    double result;
+#ifdef EXECUTABLE_MEMORY_LIMIT
+    size_t bytesAllocated = DemandExecutableAllocator::bytesAllocatedByAllAllocators() + addedMemoryUsage;
+    if (bytesAllocated >= EXECUTABLE_MEMORY_LIMIT)
+        bytesAllocated = EXECUTABLE_MEMORY_LIMIT;
+    result = static_cast<double>(EXECUTABLE_MEMORY_LIMIT) /
+        (EXECUTABLE_MEMORY_LIMIT - bytesAllocated);
+#else
+    UNUSED_PARAM(addedMemoryUsage);
+    result = 1.0;
+#endif
+    if (result < 1.0)
+        result = 1.0;
+    return result;
+
+}
+
+RefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(VM&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
+{
+    RefPtr<ExecutableMemoryHandle> result = allocator()->allocate(sizeInBytes, ownerUID);
+    RELEASE_ASSERT(result || effort != JITCompilationMustSucceed);
+    return result;
+}
+
+size_t ExecutableAllocator::committedByteCount()
+{
+    return DemandExecutableAllocator::bytesCommittedByAllocactors();
+}
+
+#if ENABLE(META_ALLOCATOR_PROFILE)
+void ExecutableAllocator::dumpProfile()
+{
+    DemandExecutableAllocator::dumpProfileFromAllAllocators();
+}
+#endif
+
+#endif // ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
+
+#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
+
+#if OS(WINDOWS)
+#error "ASSEMBLER_WX_EXCLUSIVE not yet suported on this platform."
+#endif
+
+void ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
+{
+    size_t pageSize = WTF::pageSize();
+
+    // Calculate the start of the page containing this region,
+    // and account for this extra memory within size.
+    intptr_t startPtr = reinterpret_cast<intptr_t>(start);
+    intptr_t pageStartPtr = startPtr & ~(pageSize - 1);
+    void* pageStart = reinterpret_cast<void*>(pageStartPtr);
+    size += (startPtr - pageStartPtr);
+
+    // Round size up
+    size += (pageSize - 1);
+    size &= ~(pageSize - 1);
+
+    mprotect(pageStart, size, (setting == Writable) ? PROTECTION_FLAGS_RW : PROTECTION_FLAGS_RX);
+}
+
+#endif
 
 }