--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hostsupport/hostopenvg/src/sfFunctionCache.h Wed Oct 06 17:59:01 2010 +0100
@@ -0,0 +1,310 @@
+/* Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and /or associated documentation files
+ * (the "Materials "), to deal in the Materials without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Materials,
+ * and to permit persons to whom the Materials are furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Materials.
+ *
+ * THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE MATERIALS OR
+ * THE USE OR OTHER DEALINGS IN THE MATERIALS.
+ */
+
+#ifndef __SFFUNCTIONCACHE_H
+#define __SFFUNCTIONCACHE_H
+
+// (LRU) Cache for compiled pixelpipe functions. Never takes ownership of
+// any of the objects.
+// \todo LRU might not be the best strategy or the best strategy might
+// depend on the use-case -> create more of these.
+
+#include "riArray.h"
+
+#if defined(__unix__)
+# include <pthread.h>
+#else
+# include <windows.h>
+#endif
+
+#include "llvm/ExecutionEngine/ExecutionEngine.h"
+#include "llvm/Module.h"
+
+namespace llvm {
+ class Function;
+}
+
+namespace OpenVGRI {
+
+template<class HashClass> class FunctionCache
+{
+private:
+ enum { IMPLEMENTATION_MAX_CACHE_ENTRIES = 1024 };
+ //enum { MAX_GLOBAL_TIME = 10000};
+ enum { MAX_GLOBAL_TIME = RI_UINT32_MAX };
+
+ struct CacheEntry
+ {
+ CacheEntry() : refCount(1) {}
+ CacheEntry(HashClass aHash, ::llvm::Function* aFunc, ::llvm::GlobalVariable* aConst, RIuint32 theUT) : refCount(1) {hash = aHash; llvmFunction = aFunc; llvmConstant = aConst; ut = theUT;}
+ bool operator==(const CacheEntry& rhs) const { return hash == rhs.hash; }
+ bool operator<(const CacheEntry& rhs) const { return ut < rhs.ut; } // Sort by time of usage.
+
+ HashClass hash;
+ ::llvm::Function* llvmFunction;
+ ::llvm::GlobalVariable* llvmConstant;
+ RIuint32 ut;
+ RIint32 refCount;
+ };
+
+public:
+ typedef CacheEntry* EntryHandle;
+
+public:
+ FunctionCache(int nMaxEntries) :
+ m_time(0)
+ {
+ // Limit so that if the cache is too large, you must optimize the implementation.
+ // Also note that the optimized pixel pipes are most likely small, so it would
+ // be better to have a fast cache and a lot of entries!
+ // \note A simple optimization is to sort the usage time sort order and remove the last
+ // item in the array (instead of the first).
+ RI_ASSERT(nMaxEntries > 0 && nMaxEntries < IMPLEMENTATION_MAX_CACHE_ENTRIES);
+ m_nMaxEntries = nMaxEntries;
+ m_entries.reserve(nMaxEntries);
+ }
+
+ ~FunctionCache()
+ {
+ for (int i = 0; i < m_entries.size(); i++)
+ {
+ clearEntry(m_entries[i]);
+ }
+ }
+
+ // This info is needed for the module to remove functions and deallocate executable
+ // functions:
+ void setLLVMInterface(::llvm::ExecutionEngine* ee, ::llvm::Module* module)
+ {
+ m_executionEngine = ee;
+ m_module = module;
+ }
+
+ // \todo If we never need the entry index, the locking can be
+ // simplified a lot.
+ // Must lock the cache during this operation!
+ EntryHandle findCachedItemByHash(const HashClass& hash)
+ {
+ acquireMutex();
+ int i = findCachedItemIndexByHash(hash, true);
+ if (i == -1)
+ {
+ releaseMutex();
+ return NULL;
+ }
+ EntryHandle handle = &m_entries[i];
+ releaseMutex();
+
+ return handle;
+ }
+
+ /**
+ * \brief Caches a function. Sets the reference count to 1
+ * \return EntryHandle != NULL on success.
+ * \todo The cache must be locked during the operation.
+ */
+ EntryHandle cacheFunction(HashClass hash, ::llvm::Function* function, ::llvm::GlobalVariable* constant)
+ {
+ acquireMutex();
+ RI_ASSERT(findCachedItemIndexByHash(hash) == -1);
+
+ if (m_entries.size() == m_nMaxEntries)
+ {
+ if (!removeLRU())
+ {
+ releaseMutex();
+ return NULL;
+ }
+ }
+
+ m_entries.push_back(CacheEntry(hash, function, constant, m_time));
+
+ RI_ASSERT(m_entries.size() > 0);
+ EntryHandle ret = &m_entries[m_entries.size()-1];
+ incrementGlobalTime();
+
+ releaseMutex();
+ return ret;
+ }
+
+ ::llvm::Function* getFunction(EntryHandle handle)
+ {
+ return handle->llvmFunction;
+ }
+
+ // \note Does not remove the function from cache!
+ void releaseEntry(EntryHandle handle)
+ {
+ RI_ASSERT(handle->refCount > 0);
+ handle->refCount--;
+ }
+
+private:
+ void incrementGlobalTime()
+ {
+ m_time++;
+ if (m_time == MAX_GLOBAL_TIME)
+ rebaseUsageTime();
+ }
+
+ void incrementAccessTime(CacheEntry &entry)
+ {
+ entry.ut = m_time;
+ incrementGlobalTime();
+ }
+
+ int findCachedItemIndexByHash(const HashClass& hash, bool reserve = false)
+ {
+ // \note Could just overload operator== from entry and use the Array.find function.
+ for (int i = 0; i < m_entries.size(); i++)
+ {
+ if (m_entries[i].hash == hash)
+ {
+ if (reserve)
+ {
+ incrementAccessTime(m_entries[i]);
+ m_entries[i].refCount++;
+ }
+ return i;
+ }
+ }
+ return -1;
+ }
+
+ void clearEntry(CacheEntry& entry)
+ {
+ m_executionEngine->freeMachineCodeForFunction(entry.llvmFunction);
+ entry.llvmFunction->eraseFromParent();
+ //entry.llvmConstant->eraseFromParent();
+ }
+
+ /**
+ * \return true if LRU item was successfully removed, false otherwise.
+ * \note Could try other pipes, but it is unlikely that the cache gets filled
+ * so soon that the blit for the least recently used blit has not been
+ * released.
+ * \todo Implement drop of other cache-entries?
+ */
+ bool removeLRU()
+ {
+ // \note This is pretty inefficient for many cache size:
+ // After first LRU removal, the cache is almost sorted anyway, so
+ // more efficient solution should be implemented.
+ //
+ m_entries.sort();
+
+ if (m_entries[0].refCount > 0)
+ return false;
+
+ clearEntry(m_entries[0]);
+ m_entries.remove(m_entries[0]);
+
+ return true;
+ }
+
+ void rebaseUsageTime()
+ {
+ RIuint32 i;
+ m_entries.sort();
+ RI_ASSERT(m_entries.size() > 0);
+ for(i = 0; i < (RIuint32)m_entries.size(); i++)
+ {
+ m_entries[i].ut = i;
+ };
+ m_time = i;
+ }
+
+ static void acquireMutex();
+ static void releaseMutex();
+
+private:
+ ::llvm::Module *m_module;
+ ::llvm::ExecutionEngine *m_executionEngine;
+
+ RIuint32 m_time;
+ Array <CacheEntry> m_entries;
+ int m_nMaxEntries;
+
+ static bool s_mutexInitialized;
+#if defined(__unix__)
+ static pthread_mutex_t s_mutex;
+#else
+ static CRITICAL_SECTION s_mutex;
+#endif
+};
+
+template<class HashClass>
+bool FunctionCache<HashClass>::s_mutexInitialized = false;
+
+#if defined(__unix__)
+template<class HashClass>
+pthread_mutex_t FunctionCache<HashClass>::s_mutex;
+#else
+template<class HashClass>
+CRITICAL_SECTION FunctionCache<HashClass>::s_mutex;
+#endif
+
+template<class HashClass>
+void FunctionCache<HashClass>::acquireMutex()
+{
+ if (!s_mutexInitialized)
+ {
+#if defined(__unix__)
+ int ret;
+ pthread_mutexattr_t attr;
+ ret = pthread_mutexattr_init(&attr); //initially not locked
+ RI_ASSERT(!ret); //check that there aren't any errors
+ ret = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE); //count the number of recursive locks
+ RI_ASSERT(!ret); //check that there aren't any errors
+ ret = pthread_mutex_init(&s_mutex, &attr);
+ pthread_mutexattr_destroy(&attr);
+ RI_ASSERT(!ret); //check that there aren't more errors
+#else
+ ::InitializeCriticalSection(&s_mutex);
+#endif
+ s_mutexInitialized = true;
+ }
+#if defined(__unix__)
+ int ret = pthread_mutex_lock(&s_mutex);
+ RI_ASSERT(!ret);
+#else
+ ::EnterCriticalSection(&s_mutex);
+#endif
+}
+
+template<class HashClass>
+void FunctionCache<HashClass>::releaseMutex()
+{
+ RI_ASSERT(s_mutexInitialized);
+#if defined(__unix__)
+ int ret = pthread_mutex_unlock(&s_mutex);
+ RI_ASSERT(!ret);
+#else
+ ::LeaveCriticalSection(&s_mutex);
+#endif
+}
+
+}
+
+
+#endif
+