Initial commit to populate CoreCLR repo

[tfs-changeset: 1407945]

1 files changed, 121 insertions, 0 deletions

diff --git a/src/jit/ssarenamestate.h b/src/jit/ssarenamestate.h
new file mode 100644
index 0000000000..d996ab3c43
--- /dev/null
+++ b/src/jit/ssarenamestate.h
@@ -0,0 +1,121 @@
+//
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information. 
+//
+
+// ==++==
+//
+
+//
+
+//
+// ==--==
+
+/*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+XX                                                                           XX
+XX                                  SSA                                      XX
+XX                                                                           XX
+XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
+*/
+
+#pragma once
+
+#include "jitstd.h"
+
+struct SsaRenameStateForBlock
+{
+    BasicBlock* m_bb;
+    unsigned    m_count;
+
+    SsaRenameStateForBlock(BasicBlock* bb, unsigned count) : m_bb(bb), m_count(count) {}
+    SsaRenameStateForBlock() : m_bb(NULL), m_count(0) {}
+};
+
+// A record indicating that local "m_loc" was defined in block "m_bb".
+struct SsaRenameStateLocDef
+{
+    BasicBlock* m_bb;
+    unsigned    m_lclNum;
+
+    SsaRenameStateLocDef(BasicBlock* bb, unsigned lclNum) : m_bb(bb), m_lclNum(lclNum) {}
+};
+
+struct SsaRenameState
+{
+    typedef jitstd::list<SsaRenameStateForBlock> Stack;
+    typedef Stack** Stacks;
+    typedef unsigned* Counts;
+    typedef jitstd::list<SsaRenameStateLocDef> DefStack;
+
+    SsaRenameState(const jitstd::allocator<int>& allocator, unsigned lvaCount);
+
+    void EnsureCounts();
+    void EnsureStacks();
+
+    // Requires "lclNum" to be a variable number for which a new count corresponding to a
+    // definition is desired. The method post increments the counter for the "lclNum."
+    unsigned CountForDef(unsigned lclNum);
+
+    // Requires "lclNum" to be a variable number for which an ssa number at the top of the
+    // stack is required i.e., for variable "uses."
+    unsigned CountForUse(unsigned lclNum);
+
+    // Requires "lclNum" to be a variable number, and requires "count" to represent
+    // an ssa number, that needs to be pushed on to the stack corresponding to the lclNum.
+    void Push(BasicBlock* bb, unsigned lclNum, unsigned count);
+    
+    // Pop all stacks that have an entry for "bb" on top.
+    void PopBlockStacks(BasicBlock* bb);
+
+    // Similar functions for the special implicit "Heap" variable.
+    unsigned CountForHeapDef()
+    {
+        if (heapCount == 0)
+            heapCount = SsaConfig::FIRST_SSA_NUM;
+        unsigned res = heapCount;
+        heapCount++;
+        return res;
+    }
+    unsigned CountForHeapUse()
+    {
+        return heapStack.back().m_count;
+    }
+
+    void PushHeap(BasicBlock* bb, unsigned count)
+    {
+        heapStack.push_back(SsaRenameStateForBlock(bb, count));
+    }
+
+    void PopBlockHeapStack(BasicBlock* bb);
+
+    unsigned HeapCount() { return heapCount; }
+
+#ifdef DEBUG
+    // Debug interface
+    void DumpStacks();
+#endif
+
+private:
+
+    // Map of lclNum -> count.
+    Counts counts;
+
+    // Map of lclNum -> SsaRenameStateForBlock.
+    Stacks stacks;
+
+    // This list represents the set of locals defined in the current block.
+    DefStack definedLocs;
+
+    // Same state for the special implicit Heap variable.
+    Stack     heapStack;
+    unsigned  heapCount;
+
+    // Number of stacks/counts to allocate.
+    unsigned  lvaCount;
+
+    // Allocator to allocate stacks.
+    jitstd::allocator<void> m_alloc;
+};
+