Reduce virtual address space use by JavaScriptCore on Symbian

JavaScriptCore is reserving 128MB address space for each instance
of JSGlobalData that is created in an app. Eg there is one per
QDeclarativeView, via QDeclarativeEngine, via QScriptEngine.
This can contribute to the app running out
of address space and then crashing.

The AlignedBlockAllocator is modified to be a process singleton so that
all JSGlobalData objects share the same instance.
Now there is only one 128MB address space reservation.

Task-number: ou1cimx1#993804
Change-Id: I9e8702810541905d5e9be197a5f6a9fe8e9bd0c5
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>
Reviewed-by: Pasi Pentikäinen <ext-pasi.a.pentikainen@nokia.com>
(cherry picked from commit 2e897ab99413bb1e4fd3f057f431785e3ac7abb0)
Reviewed-by: Jaakko Helanti <ext-jaakko.helanti@nokia.com>

4 files changed, 88 insertions, 40 deletions

diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.cpp b/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.cpp
index a7744dde72..6af1784139 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.cpp
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.cpp
@@ -135,10 +135,10 @@ Heap::Heap(JSGlobalData* globalData)
     , m_registeredThreads(0)
     , m_currentThreadRegistrar(0)
 #endif
-    , m_globalData(globalData)
 #if OS(SYMBIAN)
-    , m_blockallocator(JSCCOLLECTOR_VIRTUALMEM_RESERVATION, BLOCK_SIZE)
+    , m_blockallocator(WTF::AlignedBlockAllocator::instance(JSCCOLLECTOR_VIRTUALMEM_RESERVATION, BLOCK_SIZE))
 #endif
+    , m_globalData(globalData)
 {
     ASSERT(globalData);
     memset(&m_heap, 0, sizeof(CollectorHeap));
@@ -183,9 +183,6 @@ void Heap::destroy()
         t = next;
     }
 #endif
-#if OS(SYMBIAN)
-    m_blockallocator.destroy();
-#endif
     m_globalData = 0;
 }
 
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.h b/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.h
index d3616dc449..9c6ffa7c47 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/runtime/Collector.h
@@ -173,7 +173,7 @@ namespace JSC {
 
 #if OS(SYMBIAN)
         // Allocates collector blocks with correct alignment
-        WTF::AlignedBlockAllocator m_blockallocator; 
+        WTF::AlignedBlockAllocator& m_blockallocator;
 #endif
         
         JSGlobalData* m_globalData;
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.cpp b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.cpp
index 6a28e9ef4f..f09bf8e123 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.cpp
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.cpp
@@ -31,7 +31,7 @@
 #if OS(SYMBIAN)
 
 #include "BlockAllocatorSymbian.h"
-
+#include <e32atomics.h>
 
 namespace WTF {
 
@@ -43,40 +43,56 @@ AlignedBlockAllocator::AlignedBlockAllocator(TUint32 reservationSize, TUint32 bl
     : m_reservation(reservationSize), 
       m_blockSize(blockSize)
 {
+    TInt err = m_lock.CreateLocal();
+    __ASSERT_ALWAYS(m_map.bits, User::Panic(_L("AlignedBlkAlloc0"), err));
+
+    // Get system's page size value.
+    SYMBIAN_PAGESIZE(m_pageSize);
+
+    // We only accept multiples of system page size for both initial reservation and the alignment/block size
+    m_reservation = SYMBIAN_ROUNDUPTOMULTIPLE(m_reservation, m_pageSize);
+    __ASSERT_ALWAYS(SYMBIAN_ROUNDUPTOMULTIPLE(m_blockSize, m_pageSize), User::Panic(_L("AlignedBlkAlloc1"), KErrArgument));
 
-     // Get system's page size value.
-     SYMBIAN_PAGESIZE(m_pageSize); 
-     
-     // We only accept multiples of system page size for both initial reservation and the alignment/block size
-     m_reservation = SYMBIAN_ROUNDUPTOMULTIPLE(m_reservation, m_pageSize);
-     __ASSERT_ALWAYS(SYMBIAN_ROUNDUPTOMULTIPLE(m_blockSize, m_pageSize), User::Panic(_L("AlignedBlockAllocator1"), KErrArgument));
-     
-     // Calculate max. bit flags we need to carve a reservationSize range into blockSize-sized blocks
-     m_map.numBits = m_reservation / m_blockSize;   
-     const TUint32 bitsPerWord = 8*sizeof(TUint32); 
-     const TUint32 numWords = (m_map.numBits + bitsPerWord -1) / bitsPerWord; 
-   
-     m_map.bits = new TUint32[numWords];
-     __ASSERT_ALWAYS(m_map.bits, User::Panic(_L("AlignedBlockAllocator2"), KErrNoMemory));
-     m_map.clearAll();
-     
-     // Open a Symbian RChunk, and reserve requested virtual address range   
-     // Any thread in this process can operate this rchunk due to EOwnerProcess access rights. 
-     TInt ret = m_chunk.CreateDisconnectedLocal(0 , 0, (TInt)m_reservation , EOwnerProcess);  
-     if (ret != KErrNone) 
-         User::Panic(_L("AlignedBlockAllocator3"), ret);
-       
-     // This is the offset to m_chunk.Base() required to make it m_blockSize-aligned
-     m_offset = SYMBIAN_ROUNDUPTOMULTIPLE(TUint32(m_chunk.Base()), m_blockSize) - TUint(m_chunk.Base()); 
+    // Calculate max. bit flags we need to carve a reservationSize range into blockSize-sized blocks
+    m_map.numBits = m_reservation / m_blockSize;
+    const TUint32 bitsPerWord = 8*sizeof(TUint32);
+    const TUint32 numWords = (m_map.numBits + bitsPerWord -1) / bitsPerWord;
+
+    m_map.bits = new TUint32[numWords];
+    __ASSERT_ALWAYS(m_map.bits, User::Panic(_L("AlignedBlkAlloc2"), KErrNoMemory));
+    m_map.clearAll();
 
+    // Open a Symbian RChunk, and reserve requested virtual address range
+    // Any thread in this process can operate this rchunk due to EOwnerProcess access rights.
+    TInt ret = m_chunk.CreateDisconnectedLocal(0 , 0, (TInt)m_reservation , EOwnerProcess);
+    if (ret != KErrNone)
+        User::Panic(_L("AlignedBlkAlloc3"), ret);
+
+    // This is the offset to m_chunk.Base() required to make it m_blockSize-aligned
+    m_offset = SYMBIAN_ROUNDUPTOMULTIPLE(TUint32(m_chunk.Base()), m_blockSize) - TUint(m_chunk.Base());
 }
 
-void* AlignedBlockAllocator::alloc()
+struct AlignedBlockAllocatorScopeLock
 {
+    RFastLock& lock;
+    AlignedBlockAllocatorScopeLock(RFastLock& aLock) : lock(aLock)
+    {
+        lock.Wait();
+    }
+    ~AlignedBlockAllocatorScopeLock()
+    {
+        lock.Signal();
+    }
+};
 
+void* AlignedBlockAllocator::alloc()
+{
     TInt  freeRam = 0; 
     void* address = 0;
-    
+
+    // lock until this function returns
+    AlignedBlockAllocatorScopeLock lock(m_lock);
+
     // Look up first free slot in bit map
     const TInt freeIdx = m_map.findFree();
         
@@ -100,11 +116,14 @@ void* AlignedBlockAllocator::alloc()
 
 void AlignedBlockAllocator::free(void* block)
 {
+    // lock until this function returns
+    AlignedBlockAllocatorScopeLock lock(m_lock);
+
     // Calculate index of block to be freed
     TInt idx = TUint(static_cast<TUint8*>(block) - m_chunk.Base() - m_offset) / m_blockSize;
     
-    __ASSERT_DEBUG(idx >= 0 && idx < m_map.numBits, User::Panic(_L("AlignedBlockAllocator4"), KErrCorrupt)); // valid index check
-    __ASSERT_DEBUG(m_map.get(idx), User::Panic(_L("AlignedBlockAllocator5"), KErrCorrupt)); // in-use flag check    
+    __ASSERT_DEBUG(idx >= 0 && idx < m_map.numBits, User::Panic(_L("AlignedBlkAlloc4"), KErrCorrupt)); // valid index check
+    __ASSERT_DEBUG(m_map.get(idx), User::Panic(_L("AlignedBlkAlloc5"), KErrCorrupt)); // in-use flag check
     
     // Return committed region to system RAM pool (the physical RAM becomes usable by others)
     TInt ret = m_chunk.Decommit(m_offset + m_blockSize * idx, m_blockSize);
@@ -127,6 +146,33 @@ AlignedBlockAllocator::~AlignedBlockAllocator()
     delete [] m_map.bits;
 }
 
+struct AlignedBlockAllocatorPtr
+{
+    AlignedBlockAllocator* ptr;
+    ~AlignedBlockAllocatorPtr()
+    {
+        delete ptr;
+        ptr = 0;
+    }
+};
+
+AlignedBlockAllocator& AlignedBlockAllocator::instance(TUint32 reservationSize, TUint32 blockSize)
+{
+    // static cleanup for plugin unload case where leaking this much address space would not be good.
+    static AlignedBlockAllocatorPtr pAllocator;
+    // static data is zero initialized, so using zero to indicate not-yet-created.
+    if (!pAllocator.ptr)
+    {
+        AlignedBlockAllocator* newAllocator = new AlignedBlockAllocator(reservationSize, blockSize);
+        AlignedBlockAllocator* expected = 0;
+        // atomic if (pAllocator == 0) pAllocator = newAllocator; else delete newAllocator;
+        if (!__e32_atomic_cas_ord_ptr(&pAllocator.ptr, &expected, newAllocator))
+            delete newAllocator;
+        __ASSERT_ALWAYS(pAllocator.ptr, User::Panic(_L("AlignedBlkAlloc6"), KErrNoMemory));
+    }
+    return *pAllocator.ptr;
+}
+
 } // end of namespace
 
 #endif // SYMBIAN
diff --git a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.h b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.h
index 21422f6208..5f1a8cab07 100644
--- a/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.h
+++ b/src/3rdparty/javascriptcore/JavaScriptCore/wtf/symbian/BlockAllocatorSymbian.h
@@ -60,18 +60,22 @@ namespace WTF {
  */
 class AlignedBlockAllocator {
     public:
+        static AlignedBlockAllocator& instance(TUint32 reservationSize, TUint32 blockSize);
+        void* alloc();
+        void free(void* data);
+
+    private:
         AlignedBlockAllocator(TUint32 reservationSize, TUint32 blockSize);
         ~AlignedBlockAllocator();
         void destroy();
-        void* alloc();
-        void free(void* data);
-    
-    private: 
+
+    private:
         RChunk   m_chunk; // Symbian chunk that lets us reserve/commit/decommit
         TUint    m_offset; // offset of first committed region from base 
         TInt     m_pageSize; // cached value of system page size, typically 4K on Symbian
         TUint32  m_reservation;
-        TUint32  m_blockSize;  
+        TUint32  m_blockSize;
+        RFastLock m_lock;
 
         // Tracks comitted/decommitted state of a blockSize region
         struct {
@@ -111,6 +115,7 @@ class AlignedBlockAllocator {
             
         } m_map;  
 
+        friend class AlignedBlockAllocatorPtr;
 };
  
 }