The Tor Browser: js/src/assembler/jit/ExecutableAllocator.h@6474c204b198 (annotated)

js/src/assembler/jit/ExecutableAllocator.h@6474c204b198 (annotated)

js/src/assembler/jit/ExecutableAllocator.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /*
  * 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 assembler_jit_ExecutableAllocator_h
 #define assembler_jit_ExecutableAllocator_h
 #include <stddef.h> // for ptrdiff_t
 #include <limits>
 #include "jsalloc.h"
 #include "assembler/wtf/Platform.h"
 #include "jit/arm/Simulator-arm.h"
 #include "js/HashTable.h"
 #include "js/Vector.h"
 #if WTF_CPU_SPARC
 #ifdef linux  // bugzilla 502369
 static void sync_instruction_memory(caddr_t v, u_int len)
 {
     caddr_t end = v + len;
     caddr_t p = v;
     while (p < end) {
         asm("flush %0" : : "r" (p));
         p += 32;
     }
 }
 #else
 extern  "C" void sync_instruction_memory(caddr_t v, u_int len);
 #endif
 #endif
 #if WTF_OS_IOS
 #include <libkern/OSCacheControl.h>
 #include <sys/mman.h>
 #endif
 #if WTF_OS_SYMBIAN
 #include <e32std.h>
 #endif
 #if WTF_CPU_MIPS && WTF_OS_LINUX
 #include <sys/cachectl.h>
 #endif
 #if ENABLE_ASSEMBLER_WX_EXCLUSIVE
 #define PROTECTION_FLAGS_RW (PROT_READ | PROT_WRITE)
 #define PROTECTION_FLAGS_RX (PROT_READ | PROT_EXEC)
 #define INITIAL_PROTECTION_FLAGS PROTECTION_FLAGS_RX
 #else
 #define INITIAL_PROTECTION_FLAGS (PROT_READ | PROT_WRITE | PROT_EXEC)
 #endif
 namespace JSC {
   enum CodeKind { ION_CODE = 0, BASELINE_CODE, REGEXP_CODE, OTHER_CODE };
 }
 #if ENABLE_ASSEMBLER
 //#define DEBUG_STRESS_JSC_ALLOCATOR
 namespace JS {
     struct CodeSizes;
 }
 namespace JSC {
   class ExecutableAllocator;
   // 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;
 #if WTF_OS_SYMBIAN
         RChunk* chunk;
 #endif
     };
     ExecutableAllocator* m_allocator;
     char* m_freePtr;
     char* m_end;
     Allocation m_allocation;
     // Reference count for automatic reclamation.
     unsigned m_refCount;
     // Number of bytes currently used for Method and Regexp JIT code.
     size_t m_ionCodeBytes;
     size_t m_baselineCodeBytes;
     size_t m_regexpCodeBytes;
     size_t m_otherCodeBytes;
 public:
     void release(bool willDestroy = false)
     {
         JS_ASSERT(m_refCount != 0);
         // XXX: disabled, see bug 654820.
         //JS_ASSERT_IF(willDestroy, m_refCount == 1);
         if (--m_refCount == 0)
             js_delete(this);
     }
     void release(size_t n, CodeKind kind)
     {
         switch (kind) {
           case ION_CODE:
             m_ionCodeBytes -= n;
             MOZ_ASSERT(m_ionCodeBytes < m_allocation.size); // Shouldn't underflow.
             break;
           case BASELINE_CODE:
             m_baselineCodeBytes -= n;
             MOZ_ASSERT(m_baselineCodeBytes < m_allocation.size);
             break;
           case REGEXP_CODE:
             m_regexpCodeBytes -= n;
             MOZ_ASSERT(m_regexpCodeBytes < m_allocation.size);
             break;
           case OTHER_CODE:
             m_otherCodeBytes -= n;
             MOZ_ASSERT(m_otherCodeBytes < m_allocation.size);
             break;
           default:
             MOZ_ASSUME_UNREACHABLE("bad code kind");
         }
         release();
     }
     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_ionCodeBytes(0), m_baselineCodeBytes(0), m_regexpCodeBytes(0),
         m_otherCodeBytes(0)
     { }
     ~ExecutablePool();
 private:
     // It should be impossible for us to roll over, because only small
     // pools have multiple holders, and they have one holder per chunk
     // of generated code, and they only hold 16KB or so of code.
     void addRef()
     {
         JS_ASSERT(m_refCount);
         ++m_refCount;
     }
     void* alloc(size_t n, CodeKind kind)
     {
         JS_ASSERT(n <= available());
         void *result = m_freePtr;
         m_freePtr += n;
         switch (kind) {
           case ION_CODE:      m_ionCodeBytes      += n;        break;
           case BASELINE_CODE: m_baselineCodeBytes += n;        break;
           case REGEXP_CODE:   m_regexpCodeBytes   += n;        break;
           case OTHER_CODE:    m_otherCodeBytes    += n;        break;
           default:            MOZ_ASSUME_UNREACHABLE("bad code kind");
         }
         return result;
     }
     size_t available() const {
         JS_ASSERT(m_end >= m_freePtr);
         return m_end - m_freePtr;
     }
     void toggleAllCodeAsAccessible(bool accessible);
     bool codeContains(char* address) {
         return address >= m_allocation.pages && address < m_freePtr;
     }
 };
 class ExecutableAllocator {
     typedef void (*DestroyCallback)(void* addr, size_t size);
     enum ProtectionSetting { Writable, Executable };
     DestroyCallback destroyCallback;
 public:
     ExecutableAllocator()
       : destroyCallback(NULL)
     {
         if (!pageSize) {
             pageSize = determinePageSize();
             /*
              * On Windows, VirtualAlloc effectively allocates in 64K chunks.
              * (Technically, it allocates in page chunks, but the starting
              * address is always a multiple of 64K, so each allocation uses up
              * 64K of address space.)  So a size less than that would be
              * pointless.  But it turns out that 64KB is a reasonable size for
              * all platforms.  (This assumes 4KB pages.)
              */
             largeAllocSize = pageSize * 16;
         }
         JS_ASSERT(m_smallPools.empty());
     }
     ~ExecutableAllocator()
     {
         for (size_t i = 0; i < m_smallPools.length(); i++)
             m_smallPools[i]->release(/* willDestroy = */true);
         // If this asserts we have a pool leak.
         JS_ASSERT_IF(m_pools.initialized(), m_pools.empty());
     }
     void purge() {
         for (size_t i = 0; i < m_smallPools.length(); i++)
             m_smallPools[i]->release();
         m_smallPools.clear();
     }
     // 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(size_t n, ExecutablePool** poolp, CodeKind type)
     {
         // Caller must ensure 'n' is word-size aligned. If all allocations are
         // of word sized quantities, then all subsequent allocations will be
         // aligned.
         JS_ASSERT(roundUpAllocationSize(n, sizeof(void*)) == n);
         if (n == OVERSIZE_ALLOCATION) {
             *poolp = NULL;
             return NULL;
         }
         *poolp = poolForSize(n);
         if (!*poolp)
             return NULL;
         // This alloc is infallible because poolForSize() just obtained
         // (found, or created if necessary) a pool that had enough space.
         void *result = (*poolp)->alloc(n, type);
         JS_ASSERT(result);
         return result;
     }
     void releasePoolPages(ExecutablePool *pool) {
         JS_ASSERT(pool->m_allocation.pages);
         if (destroyCallback)
             destroyCallback(pool->m_allocation.pages, pool->m_allocation.size);
         systemRelease(pool->m_allocation);
         JS_ASSERT(m_pools.initialized());
         m_pools.remove(m_pools.lookup(pool));   // this asserts if |pool| is not in m_pools
     }
     void addSizeOfCode(JS::CodeSizes *sizes) const;
     void toggleAllCodeAsAccessible(bool accessible);
     bool codeContains(char* address);
     void setDestroyCallback(DestroyCallback destroyCallback) {
         this->destroyCallback = destroyCallback;
     }
 private:
     static size_t pageSize;
     static size_t largeAllocSize;
 #if WTF_OS_WINDOWS
     static uint64_t rngSeed;
 #endif
     static const size_t OVERSIZE_ALLOCATION = size_t(-1);
     static size_t roundUpAllocationSize(size_t request, size_t granularity)
     {
         // Something included via windows.h defines a macro with this name,
         // which causes the function below to fail to compile.
         #ifdef _MSC_VER
         # undef max
         #endif
         if ((std::numeric_limits<size_t>::max() - granularity) <= request)
             return OVERSIZE_ALLOCATION;
         // Round up to next page boundary
         size_t size = request + (granularity - 1);
         size = size & ~(granularity - 1);
         JS_ASSERT(size >= request);
         return size;
     }
     // On OOM, this will return an Allocation where pages is NULL.
     ExecutablePool::Allocation systemAlloc(size_t n);
     static void systemRelease(const ExecutablePool::Allocation& alloc);
     void *computeRandomAllocationAddress();
     ExecutablePool* createPool(size_t n)
     {
         size_t allocSize = roundUpAllocationSize(n, pageSize);
         if (allocSize == OVERSIZE_ALLOCATION)
             return NULL;
         if (!m_pools.initialized() && !m_pools.init())
             return NULL;
 #ifdef DEBUG_STRESS_JSC_ALLOCATOR
         ExecutablePool::Allocation a = systemAlloc(size_t(4294967291));
 #else
         ExecutablePool::Allocation a = systemAlloc(allocSize);
 #endif
         if (!a.pages)
             return NULL;
         ExecutablePool *pool = js_new<ExecutablePool>(this, a);
         if (!pool) {
             systemRelease(a);
             return NULL;
         }
         m_pools.put(pool);
         return pool;
     }
 public:
     ExecutablePool* poolForSize(size_t n)
     {
 #ifndef DEBUG_STRESS_JSC_ALLOCATOR
         // Try to fit in an existing small allocator.  Use the pool with the
         // least available space that is big enough (best-fit).  This is the
         // best strategy because (a) it maximizes the chance of the next
         // allocation fitting in a small pool, and (b) it minimizes the
         // potential waste when a small pool is next abandoned.
         ExecutablePool *minPool = NULL;
         for (size_t i = 0; i < m_smallPools.length(); i++) {
             ExecutablePool *pool = m_smallPools[i];
             if (n <= pool->available() && (!minPool || pool->available() < minPool->available()))
                 minPool = pool;
         }
         if (minPool) {
             minPool->addRef();
             return minPool;
         }
 #endif
         // If the request is large, we just provide a unshared allocator
         if (n > largeAllocSize)
             return createPool(n);
         // Create a new allocator
         ExecutablePool* pool = createPool(largeAllocSize);
         if (!pool)
             return NULL;
         // At this point, local |pool| is the owner.
         if (m_smallPools.length() < maxSmallPools) {
             // We haven't hit the maximum number of live pools;  add the new pool.
             m_smallPools.append(pool);
             pool->addRef();
         } else {
             // Find the pool with the least space.
             int iMin = 0;
             for (size_t i = 1; i < m_smallPools.length(); i++)
                 if (m_smallPools[i]->available() <
                     m_smallPools[iMin]->available())
                 {
                     iMin = i;
                 }
             // If the new allocator will result in more free space than the small
             // pool with the least space, then we will use it instead
             ExecutablePool *minPool = m_smallPools[iMin];
             if ((pool->available() - n) > minPool->available()) {
                 minPool->release();
                 m_smallPools[iMin] = pool;
                 pool->addRef();
             }
         }
         // Pass ownership to the caller.
         return pool;
     }
 #if ENABLE_ASSEMBLER_WX_EXCLUSIVE
     static void makeWritable(void* start, size_t size)
     {
         reprotectRegion(start, size, Writable);
     }
     static void makeExecutable(void* start, size_t size)
     {
         reprotectRegion(start, size, Executable);
     }
 #else
     static void makeWritable(void*, size_t) {}
     static void makeExecutable(void*, size_t) {}
 #endif
 #if WTF_CPU_X86 || WTF_CPU_X86_64
     static void cacheFlush(void*, size_t)
     {
     }
 #elif defined(JS_ARM_SIMULATOR)
     static void cacheFlush(void *code, size_t size)
     {
         js::jit::Simulator::FlushICache(code, size);
     }
 #elif WTF_CPU_MIPS
     static void cacheFlush(void* code, size_t size)
     {
 #if WTF_COMPILER_GCC && (GCC_VERSION >= 40300)
 #if WTF_MIPS_ISA_REV(2) && (GCC_VERSION < 40403)
         int lineSize;
         asm("rdhwr %0, $1" : "=r" (lineSize));
         //
         // Modify "start" and "end" to avoid GCC 4.3.0-4.4.2 bug in
         // mips_expand_synci_loop that may execute synci one more time.
         // "start" points to the first byte of the cache line.
         // "end" points to the last byte of the line before the last cache line.
         // Because size is always a multiple of 4, this is safe to set
         // "end" to the last byte.
         //
         intptr_t start = reinterpret_cast<intptr_t>(code) & (-lineSize);
         intptr_t end = ((reinterpret_cast<intptr_t>(code) + size - 1) & (-lineSize)) - 1;
         __builtin___clear_cache(reinterpret_cast<char*>(start), reinterpret_cast<char*>(end));
 #else
         intptr_t end = reinterpret_cast<intptr_t>(code) + size;
         __builtin___clear_cache(reinterpret_cast<char*>(code), reinterpret_cast<char*>(end));
 #endif
 #else
         _flush_cache(reinterpret_cast<char*>(code), size, BCACHE);
 #endif
     }
 #elif WTF_CPU_ARM && WTF_OS_IOS
     static void cacheFlush(void* code, size_t size)
     {
         sys_dcache_flush(code, size);
         sys_icache_invalidate(code, size);
     }
 #elif WTF_CPU_ARM_THUMB2 && WTF_IOS
     static void cacheFlush(void* code, size_t size)
     {
         asm volatile (
             "push    {r7}\n"
             "mov     r0, %0\n"
             "mov     r1, %1\n"
             "movw    r7, #0x2\n"
             "movt    r7, #0xf\n"
             "movs    r2, #0x0\n"
             "svc     0x0\n"
             "pop     {r7}\n"
             :
             : "r" (code), "r" (reinterpret_cast<char*>(code) + size)
             : "r0", "r1", "r2");
     }
 #elif WTF_OS_SYMBIAN
     static void cacheFlush(void* code, size_t size)
     {
         User::IMB_Range(code, static_cast<char*>(code) + size);
     }
 #elif WTF_CPU_ARM_TRADITIONAL && WTF_OS_LINUX && WTF_COMPILER_RVCT
     static __asm void cacheFlush(void* code, size_t size);
 #elif WTF_CPU_ARM_TRADITIONAL && (WTF_OS_LINUX || WTF_OS_ANDROID) && WTF_COMPILER_GCC
     static void cacheFlush(void* code, size_t size)
     {
         asm volatile (
             "push    {r7}\n"
             "mov     r0, %0\n"
             "mov     r1, %1\n"
             "mov     r7, #0xf0000\n"
             "add     r7, r7, #0x2\n"
             "mov     r2, #0x0\n"
             "svc     0x0\n"
             "pop     {r7}\n"
             :
             : "r" (code), "r" (reinterpret_cast<char*>(code) + size)
             : "r0", "r1", "r2");
     }
 #elif WTF_CPU_SPARC
     static void cacheFlush(void* code, size_t size)
     {
         sync_instruction_memory((caddr_t)code, size);
     }
 #endif
 private:
 #if ENABLE_ASSEMBLER_WX_EXCLUSIVE
     static void reprotectRegion(void*, size_t, ProtectionSetting);
 #endif
     // 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.
     static size_t determinePageSize();
 };
 }
 #endif // ENABLE(ASSEMBLER)
 #endif /* assembler_jit_ExecutableAllocator_h */

The Tor Browser / annotate

js/src/assembler/jit/ExecutableAllocator.h@6474c204b198 (annotated)

js/src/assembler/jit/ExecutableAllocator.h