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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
*
* Copyright (C) 2008 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef jit_ExecutableAllocator_h
#define jit_ExecutableAllocator_h
#include "mozilla/EnumeratedArray.h"
#include "mozilla/Maybe.h"
#include "mozilla/XorShift128PlusRNG.h"
#include <limits>
#include <stddef.h> // for ptrdiff_t
#include "jit/ProcessExecutableMemory.h"
#include "js/AllocPolicy.h"
#include "js/HashTable.h"
#include "js/TypeDecls.h"
#include "js/Vector.h"
namespace JS {
struct CodeSizes;
} // namespace JS
namespace js {
namespace jit {
enum class CodeKind : uint8_t { Ion, Baseline, RegExp, Other, Count };
class ExecutableAllocator;
class JitRuntime;
// These are reference-counted. A new one starts with a count of 1.
class ExecutablePool {
friend class ExecutableAllocator;
private:
struct Allocation {
char* pages;
size_t size;
};
ExecutableAllocator* m_allocator;
char* m_freePtr;
char* m_end;
Allocation m_allocation;
// Reference count for automatic reclamation.
unsigned m_refCount : 31;
// Flag that can be used by algorithms operating on pools.
bool m_mark : 1;
// Number of bytes currently allocated for each CodeKind.
mozilla::EnumeratedArray<CodeKind, CodeKind::Count, size_t> m_codeBytes;
public:
void release(bool willDestroy = false);
void release(size_t n, CodeKind kind);
void addRef();
ExecutablePool(ExecutableAllocator* allocator, Allocation a)
: m_allocator(allocator),
m_freePtr(a.pages),
m_end(m_freePtr + a.size),
m_allocation(a),
m_refCount(1),
m_mark(false) {
for (size_t& count : m_codeBytes) {
count = 0;
}
}
~ExecutablePool();
void mark() {
MOZ_ASSERT(!m_mark);
m_mark = true;
}
void unmark() {
MOZ_ASSERT(m_mark);
m_mark = false;
}
bool isMarked() const { return m_mark; }
private:
ExecutablePool(const ExecutablePool&) = delete;
void operator=(const ExecutablePool&) = delete;
void* alloc(size_t n, CodeKind kind);
size_t available() const;
// Returns the number of bytes that are currently in use (referenced by
// live JitCode objects).
size_t usedCodeBytes() const {
size_t res = 0;
for (size_t count : m_codeBytes) {
res += count;
}
return res;
}
};
struct JitPoisonRange {
jit::ExecutablePool* pool;
void* start;
size_t size;
JitPoisonRange(jit::ExecutablePool* pool, void* start, size_t size)
: pool(pool), start(start), size(size) {}
};
typedef Vector<JitPoisonRange, 0, SystemAllocPolicy> JitPoisonRangeVector;
class ExecutableAllocator {
public:
ExecutableAllocator() = default;
~ExecutableAllocator();
void purge();
// alloc() returns a pointer to some memory, and also (by reference) a
// pointer to reference-counted pool. The caller owns a reference to the
// pool; i.e. alloc() increments the count before returning the object.
void* alloc(JSContext* cx, size_t n, ExecutablePool** poolp, CodeKind type);
void releasePoolPages(ExecutablePool* pool);
void addSizeOfCode(JS::CodeSizes* sizes) const;
private:
static const size_t OVERSIZE_ALLOCATION = size_t(-1);
static size_t roundUpAllocationSize(size_t request, size_t granularity);
// On OOM, this will return an Allocation where pages is nullptr.
ExecutablePool::Allocation systemAlloc(size_t n);
static void systemRelease(const ExecutablePool::Allocation& alloc);
ExecutablePool* createPool(size_t n);
ExecutablePool* poolForSize(size_t n);
static void reprotectPool(JSRuntime* rt, ExecutablePool* pool,
ProtectionSetting protection,
MustFlushICache flushICache);
public:
[[nodiscard]] static bool makeWritable(void* start, size_t size) {
return ReprotectRegion(start, size, ProtectionSetting::Writable,
MustFlushICache::No);
}
[[nodiscard]] static bool makeExecutableAndFlushICache(
FlushICacheSpec flushSpec, void* start, size_t size) {
MustFlushICache mustFlushICache;
switch (flushSpec) {
case FlushICacheSpec::LocalThreadOnly:
mustFlushICache = MustFlushICache::LocalThreadOnly;
break;
case FlushICacheSpec::AllThreads:
mustFlushICache = MustFlushICache::AllThreads;
break;
}
return ReprotectRegion(start, size, ProtectionSetting::Executable,
mustFlushICache);
}
static void poisonCode(JSRuntime* rt, JitPoisonRangeVector& ranges);
private:
ExecutableAllocator(const ExecutableAllocator&) = delete;
void operator=(const ExecutableAllocator&) = delete;
// These are strong references; they keep pools alive.
static const size_t maxSmallPools = 4;
typedef js::Vector<ExecutablePool*, maxSmallPools, js::SystemAllocPolicy>
SmallExecPoolVector;
SmallExecPoolVector m_smallPools;
// All live pools are recorded here, just for stats purposes. These are
// weak references; they don't keep pools alive. When a pool is destroyed
// its reference is removed from m_pools.
typedef js::HashSet<ExecutablePool*, js::DefaultHasher<ExecutablePool*>,
js::SystemAllocPolicy>
ExecPoolHashSet;
ExecPoolHashSet m_pools; // All pools, just for stats purposes.
};
} // namespace jit
} // namespace js
#endif /* jit_ExecutableAllocator_h */
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