Merge WebKit at r84325: Initial merge by git.

Change-Id: Ic1a909300ecc0a13ddc6b4e784371d2ac6e3d59b

1 files changed, 45 insertions, 3 deletions

diff --git a/Source/JavaScriptCore/dfg/DFGGraph.h b/Source/JavaScriptCore/dfg/DFGGraph.h
index c02110e..c6bc7df 100644
--- a/Source/JavaScriptCore/dfg/DFGGraph.h
+++ b/Source/JavaScriptCore/dfg/DFGGraph.h
@@ -30,6 +30,7 @@
 
 #include <dfg/DFGNode.h>
 #include <wtf/Vector.h>
+#include <wtf/StdLibExtras.h>
 
 namespace JSC {
 
@@ -37,6 +38,26 @@ class CodeBlock;
 
 namespace DFG {
 
+typedef uint32_t BlockIndex;
+
+struct BasicBlock {
+    BasicBlock(unsigned bytecodeBegin, NodeIndex begin, NodeIndex end)
+        : bytecodeBegin(bytecodeBegin)
+        , begin(begin)
+        , end(end)
+    {
+    }
+
+    static inline BlockIndex getBytecodeBegin(BasicBlock* block)
+    {
+        return block->bytecodeBegin;
+    }
+
+    unsigned bytecodeBegin;
+    NodeIndex begin;
+    NodeIndex end;
+};
+
 // 
 // === Graph ===
 //
@@ -48,19 +69,40 @@ public:
     // Mark a node as being referenced.
     void ref(NodeIndex nodeIndex)
     {
-        // If the value (before incrementing) was at reCount zero then we need to ref its children.
-        if (!at(nodeIndex).refCount++)
+        Node& node = at(nodeIndex);
+        // If the value (before incrementing) was at refCount zero then we need to ref its children.
+        if (!node.refCount++)
             refChildren(nodeIndex);
     }
+    void deref(NodeIndex nodeIndex)
+    {
+        Node& node = at(nodeIndex);
+        ASSERT(node.refCount);
+        // If the value (after decrementing) becomes refCount zero then we need to deref its children.
+        if (!--node.refCount)
+            derefChildren(nodeIndex);
+    }
 
 #ifndef NDEBUG
     // CodeBlock is optional, but may allow additional information to be dumped (e.g. Identifier names).
     void dump(CodeBlock* = 0);
+    void dump(NodeIndex, CodeBlock* = 0);
 #endif
 
+    Vector<BasicBlock> m_blocks;
+
+    BlockIndex blockIndexForBytecodeOffset(unsigned bytecodeBegin)
+    {
+        BasicBlock* begin = m_blocks.begin();
+        BasicBlock* block = binarySearch<BasicBlock, unsigned, BasicBlock::getBytecodeBegin>(begin, m_blocks.size(), bytecodeBegin);
+        ASSERT(block >= m_blocks.begin() && block < m_blocks.end());
+        return static_cast<BlockIndex>(block - begin);
+    }
+
 private:
-    // When a node's refCount goes from 0 to 1, it must (logically) recursively ref all of its children.
+    // When a node's refCount goes from 0 to 1, it must (logically) recursively ref all of its children, and vice versa.
     void refChildren(NodeIndex);
+    void derefChildren(NodeIndex);
 };
 
 } } // namespace JSC::DFG