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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5259 91177308-0d34-0410-b5e6-96231b3b80d8

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diff --git a/include/llvm/CodeGen/LiveVariables.h b/include/llvm/CodeGen/LiveVariables.h
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+//===-- llvm/CodeGen/LiveVariables.h - Live Variable Analysis ---*- C++ -*-===//
+// 
+// This class computes live variables using are sparse implementation based on
+// the machine code SSA form.  This class computes live variable information for
+// each virtual and physical register in a function.  It uses the dominance
+// properties of SSA form to efficiently compute live variables for virtual
+// registers, and assumes that physical registers are only live within a single
+// basic block (allowing it to do a single local analysis to resolve physical
+// register lifetimes in each basic block).
+//   
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_LIVEVARIABLES_H
+#define LLVM_CODEGEN_LIVEVARIABLES_H
+
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include <map>
+
+class MRegisterInfo;
+
+class LiveVariables : public MachineFunctionPass {
+  struct VarInfo {
+    /// DefBlock - The basic block which defines this value...
+    MachineBasicBlock *DefBlock;
+    MachineInstr      *DefInst;
+
+    /// AliveBlocks - Set of blocks of which this value is alive completely
+    /// through.  This is a bit set which uses the basic block number as an
+    /// index.
+    ///
+    std::vector<bool> AliveBlocks;
+
+    /// Kills - List of MachineBasicblock's which contain the last use of this
+    /// virtual register (kill it).  This also includes the specific instruction
+    /// which kills the value.
+    ///
+    std::vector<std::pair<MachineBasicBlock*, MachineInstr*> > Kills;
+
+    VarInfo() : DefBlock(0), DefInst(0) {}
+  };
+
+  /// VirtRegInfo - This list is a mapping from virtual register number to
+  /// variable information.  FirstVirtualRegister is subtracted from the virtual
+  /// register number before indexing into this list.
+  ///
+  std::vector<VarInfo> VirtRegInfo;
+
+  /// RegistersKilled - This multimap keeps track of all of the registers that
+  /// are dead immediately after an instruction reads its operands.  If an
+  /// instruction does not have an entry in this map, it kills no registers.
+  ///
+  std::multimap<MachineInstr*, unsigned> RegistersKilled;
+
+  /// RegistersDead - This multimap keeps track of all of the registers that are
+  /// dead immediately after an instruction executes, which are not dead after
+  /// the operands are evaluated.  In practice, this only contains registers
+  /// which are defined by an instruction, but never used.
+  ///
+  std::multimap<MachineInstr*, unsigned> RegistersDead;
+
+private:   // Intermediate data structures
+
+  /// BBMap - Maps LLVM basic blocks to their corresponding machine basic block.
+  /// This also provides a numbering of the basic blocks in the function.
+  std::map<const BasicBlock*, std::pair<MachineBasicBlock*, unsigned> > BBMap;
+  
+  const MRegisterInfo *RegInfo;
+
+  MachineInstr **PhysRegInfo;
+  bool          *PhysRegUsed;
+
+public:
+
+  virtual bool runOnMachineFunction(MachineFunction &MF);
+
+  /// killed_iterator - Iterate over registers killed by a machine instruction
+  ///
+  typedef std::multimap<MachineInstr*,
+			unsigned>::const_iterator killed_iterator;
+  
+  /// killed_begin/end - Get access to the range of registers killed by a
+  /// machine instruction.
+  killed_iterator killed_begin(MachineInstr *MI) const {
+    return RegistersKilled.lower_bound(MI);
+  }
+  killed_iterator killed_end(MachineInstr *MI) const {
+    return RegistersKilled.upper_bound(MI);
+  }
+
+  killed_iterator dead_begin(MachineInstr *MI) const {
+    return RegistersDead.lower_bound(MI);
+  }
+  killed_iterator dead_end(MachineInstr *MI) const {
+    return RegistersDead.upper_bound(MI);
+  }
+
+  /// addVirtualRegisterKill - Add information about the fact that the specified
+  /// register is dead after being used by the specified instruction.
+  ///
+  void addVirtualRegisterKill(unsigned IncomingReg, MachineInstr *MI) {
+    RegistersDead.insert(std::make_pair(MI, IncomingReg));
+  }
+
+  virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    AU.setPreservesAll();
+  }
+
+  virtual void releaseMemory() {
+    VirtRegInfo.clear();
+    RegistersKilled.clear();
+    RegistersDead.clear();
+  }
+private:
+  VarInfo &getVarInfo(unsigned RegIdx) {
+    if (RegIdx >= VirtRegInfo.size()) {
+      if (RegIdx >= 2*VirtRegInfo.size())
+	VirtRegInfo.resize(RegIdx*2);
+      else
+	VirtRegInfo.resize(2*VirtRegInfo.size());
+    }
+    return VirtRegInfo[RegIdx];
+  }
+
+  void MarkVirtRegAliveInBlock(VarInfo &VRInfo, const BasicBlock *BB);
+  void HandleVirtRegUse(VarInfo &VRInfo, MachineBasicBlock *MBB,
+                       	MachineInstr *MI);
+  void HandlePhysRegUse(unsigned Reg, MachineInstr *MI);
+  void HandlePhysRegDef(unsigned Reg, MachineInstr *MI);
+};
+
+#endif