1 files changed, 155 insertions, 9 deletions

diff --git a/Source/JavaScriptCore/wtf/OSAllocatorSymbian.cpp b/Source/JavaScriptCore/wtf/OSAllocatorSymbian.cpp
index e746fde..c63e609 100644
--- a/Source/JavaScriptCore/wtf/OSAllocatorSymbian.cpp
+++ b/Source/JavaScriptCore/wtf/OSAllocatorSymbian.cpp
@@ -1,5 +1,6 @@
 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
+ * Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -26,31 +27,176 @@
 #include "config.h"
 #include "OSAllocator.h"
 
-#include <wtf/FastMalloc.h>
+#include "PageAllocatorSymbian.h"
 
 namespace WTF {
 
-void* OSAllocator::reserveUncommitted(size_t bytes, Usage, bool, bool)
+// Array to store code chunks used by JIT engine(s)
+static RPointerArray<SymbianChunk> codeChunksContainer;
+
+// The singleton data allocator (non code)
+static PageAllocatorSymbian dataAllocator;
+
+_LIT(KErrorStringInternalConsistency, "OSAllocator:ConsistencyError");
+_LIT(KErrorStringChunkCreation, "OSAllocator:ChunkInitError");
+_LIT(KErrorStringPageSize, "OSAllocator:WrongPageSize");
+
+// Makes a new code chunk for a JIT engine with everything in committed state
+static void* allocateCodeChunk(size_t bytes) 
+{
+    RChunk c; 
+    TInt error = c.CreateLocalCode(bytes, bytes);
+    __ASSERT_ALWAYS(error == KErrNone, User::Panic(KErrorStringChunkCreation, error));
+   
+    codeChunksContainer.Append(new SymbianChunk(c.Handle())); 
+    return static_cast<void*>(c.Base()); 
+}
+   
+// Frees the _entire_ code chunk in which this address resides. 
+static bool deallocateCodeChunk(void* address) 
+{     
+    bool found = false; 
+    for (int i = 0; i < codeChunksContainer.Count(); i++) { 
+        SymbianChunk* p = codeChunksContainer[i];
+        if (p && p->contains(address)) { 
+            codeChunksContainer.Remove(i);
+            delete p;
+            found = true;
+        }
+    }
+    return found; 
+}
+
+// Return the (singleton) object that manages all non-code VM operations
+static PageAllocatorSymbian* dataAllocatorInstance() 
 {
-    return fastMalloc(bytes);
+    return &dataAllocator; 
 }
 
-void* OSAllocator::reserveAndCommit(size_t bytes, Usage, bool, bool)
+// Reserve memory and return the base address of the region
+void* OSAllocator::reserveUncommitted(size_t reservationSize, Usage usage, bool , bool executable) 
 {
-    return fastMalloc(bytes);
+    void* base = 0; 
+    if (executable) 
+        base = allocateCodeChunk(reservationSize);
+    else
+        base = dataAllocatorInstance()->reserve(reservationSize);
+    return base; 
 }
 
-void OSAllocator::commit(void*, size_t, bool, bool)
+// Inverse operation of reserveUncommitted()
+void OSAllocator::releaseDecommitted(void* parkedBase, size_t bytes) 
 {
+    if (dataAllocatorInstance()->contains(parkedBase)) 
+        dataAllocatorInstance()->release(parkedBase, bytes);
+
+    // NOOP for code chunks (JIT) because we released them in decommit()
 }
 
-void OSAllocator::decommit(void*, size_t)
+// Commit what was previously reserved via reserveUncommitted()
+void OSAllocator::commit(void* address, size_t bytes, bool, bool executable) 
 {
+    // For code chunks, we commit (early) in reserveUncommitted(), so NOOP
+    // For data regions, do real work
+    if (!executable) 
+        dataAllocatorInstance()->commit(address, bytes);
+}
+
+void OSAllocator::decommit(void* address, size_t bytes) 
+{ 
+    if (dataAllocatorInstance()->contains(address))
+        dataAllocatorInstance()->decommit(address, bytes);
+    else
+        deallocateCodeChunk(address); // for code chunk, decommit AND release    
+}
+    
+void* OSAllocator::reserveAndCommit(size_t bytes, Usage usage, bool writable, bool executable)
+{ 
+    void* base = reserveUncommitted(bytes, usage, writable, executable);
+    commit(base, bytes, writable, executable);
+    return base;
+}
+
+
+// The PageAllocatorSymbian class helps map OSAllocator calls for reserve/commit/decommit
+// to a single large Symbian chunk. Only works with multiples of page size, and as a corollary 
+// all addresses accepted or returned by it are also page-sized aligned. 
+// Design notes: 
+// - We initialize a chunk up-front with a large reservation size
+// - The entire reservation reserve is logically divided into pageSized blocks (4K on Symbian) 
+// - The map maintains 1 bit for each of the 4K-sized region in our address space
+// - OSAllocator::reserveUncommitted() requests lead to 1 or more bits being set in map 
+//   to indicate internally reserved state. The VM address corresponding to the first bit is returned. 
+// - OSAllocator::commit() actually calls RChunk.commit() and commits *all or part* of the region 
+//   reserved via reserveUncommitted() previously. 
+// - OSAllocator::decommit() calls RChunk.decommit() 
+// - OSAllocator::releaseDecommitted() unparks all the bits in the map, but trusts that a previously
+//   call to decommit() would have returned the memory to the OS 
+PageAllocatorSymbian::PageAllocatorSymbian()
+{        
+    __ASSERT_ALWAYS(m_pageSize == WTF::pageSize(), User::Panic(KErrorStringPageSize, m_pageSize));
+    
+    RChunk chunk;
+    TInt error = chunk.CreateDisconnectedLocal(0, 0, TInt(largeReservationSize));
+    __ASSERT_ALWAYS(error == KErrNone, User::Panic(KErrorStringChunkCreation, error));
+    
+    m_chunk = new SymbianChunk(chunk.Handle()); // takes ownership of chunk
+}
+
+PageAllocatorSymbian::~PageAllocatorSymbian() 
+{
+    delete m_chunk;
+}
+
+// Reserves a region internally in the bitmap
+void* PageAllocatorSymbian::reserve(size_t bytes) 
+{ 
+    // Find first available region
+    const size_t nPages = bytes / m_pageSize;
+    const int64_t startIdx = m_map.findRunOfZeros(nPages);
+
+    // Pseudo OOM
+    if (startIdx < 0)
+        return 0;
+    
+    for (size_t i = startIdx; i < startIdx + nPages ; i++)
+        m_map.set(i);
+    
+    return static_cast<void*>( m_chunk->m_base + (TUint)(m_pageSize * startIdx) ); 
+}
+
+// Reverses the effects of a reserve() call
+void PageAllocatorSymbian::release(void* address, size_t bytes)
+{
+    const size_t startIdx = (static_cast<char*>(address) - m_chunk->m_base) / m_pageSize;
+    const size_t nPages = bytes / m_pageSize;
+    for (size_t i = startIdx; i < startIdx + nPages ; i++)
+        m_map.clear(i);
+}
+
+// Actually commit memory from the OS, after a previous call to reserve()
+bool PageAllocatorSymbian::commit(void* address, size_t bytes) 
+{ 
+    // sanity check that bits were previously set
+    const size_t idx = (static_cast<char*>(address) - m_chunk->m_base) / m_pageSize;
+    const size_t nPages = bytes / m_pageSize;
+    __ASSERT_ALWAYS(m_map.get(idx), User::Panic(KErrorStringInternalConsistency, idx));
+    __ASSERT_ALWAYS(m_map.get(idx+nPages-1), User::Panic(KErrorStringInternalConsistency, idx+nPages-1));
+    
+    TInt error = m_chunk->Commit(static_cast<char*>(address) - m_chunk->m_base, bytes);
+    return (error == KErrNone);
+}
+
+// Inverse operation of commit(), a release() should follow later
+bool PageAllocatorSymbian::decommit(void* address, size_t bytes) 
+{ 
+    TInt error = m_chunk->Decommit(static_cast<char*>(address) - m_chunk->m_base, bytes);
+    return (error == KErrNone); 
 }
 
-void OSAllocator::releaseDecommitted(void* address, size_t)
+bool PageAllocatorSymbian::contains(const void* address) const
 {
-    fastFree(address);
+    return m_chunk->contains(address);     
 }
 
 } // namespace WTF