Stack Alignment: when creating stack objects in MachineFrameInfo, make sure

[oota-llvm.git] / include / llvm / CodeGen / RegisterScavenging.h

diff --git a/include/llvm/CodeGen/RegisterScavenging.h b/include/llvm/CodeGen/RegisterScavenging.h
index 2b86e5fda7d4e352f724eff7b1acbd9e0a9f9de4..6604d4cddaae2e1cc2f37ab326974f9467fb324e 100644 (file)
--- a/include/llvm/CodeGen/RegisterScavenging.h
+++ b/include/llvm/CodeGen/RegisterScavenging.h
@@ -17,9 +17,9 @@
 #ifndef LLVM_CODEGEN_REGISTER_SCAVENGING_H
 #define LLVM_CODEGEN_REGISTER_SCAVENGING_H
 
-#include "llvm/CodeGen/MachineBasicBlock.h"
 #include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/DenseMap.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
 
 namespace llvm {
 
@@ -60,22 +60,14 @@ class RegScavenger {
   ///
   BitVector CalleeSavedRegs;
 
-  /// ReservedRegs - A bitvector of reserved registers.
-  ///
-  BitVector ReservedRegs;
-
   /// RegsAvailable - The current state of all the physical registers immediately
   /// before MBBI. One bit per physical register. If bit is set that means it's
   /// available, unset means the register is currently being used.
   BitVector RegsAvailable;
 
-  /// CurrDist - Distance from MBB entry to the current instruction MBBI.
-  ///
-  unsigned CurrDist;
-
-  /// DistanceMap - Keep track the distance of a MI from the start of the
-  /// current basic block.
-  DenseMap<MachineInstr*, unsigned> DistanceMap;
+  // These BitVectors are only used internally to forward(). They are members
+  // to avoid frequent reallocations.
+  BitVector KillRegs, DefRegs;
 
 public:
   RegScavenger()
@@ -104,37 +96,16 @@ public:
   ///
   void skipTo(MachineBasicBlock::iterator I) { MBBI = I; }
 
-  /// isReserved - Returns true if a register is reserved. It is never "unused".
-  bool isReserved(unsigned Reg) const { return ReservedRegs[Reg]; }
-
-  /// isUsed / isUsed - Test if a register is currently being used.
-  ///
-  bool isUsed(unsigned Reg) const   { return !RegsAvailable[Reg]; }
-  bool isUnused(unsigned Reg) const { return RegsAvailable[Reg]; }
-
   /// getRegsUsed - return all registers currently in use in used.
   void getRegsUsed(BitVector &used, bool includeReserved);
 
-  /// setUsed / setUnused - Mark the state of one or a number of registers.
-  ///
-  void setUsed(unsigned Reg);
-  void setUsed(BitVector &Regs) {
-    RegsAvailable &= ~Regs;
-  }
-  void setUnused(unsigned Reg, const MachineInstr *MI);
-  void setUnused(BitVector &Regs) {
-    RegsAvailable |= Regs;
-  }
-
-  /// FindUnusedReg - Find a unused register of the specified register class
-  /// from the specified set of registers. It return 0 is none is found.
-  unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
-                         const BitVector &Candidates) const;
+  /// getRegsAvailable - Return all available registers in the register class
+  /// in Mask.
+  BitVector getRegsAvailable(const TargetRegisterClass *RC);
 
   /// FindUnusedReg - Find a unused register of the specified register class.
-  /// Exclude callee saved registers if directed. It return 0 is none is found.
-  unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
-                         bool ExCalleeSaved = false) const;
+  /// Return 0 if none is found.
+  unsigned FindUnusedReg(const TargetRegisterClass *RegClass) const;
 
   /// setScavengingFrameIndex / getScavengingFrameIndex - accessor and setter of
   /// ScavengingFrameIndex.
@@ -151,20 +122,46 @@ public:
     return scavengeRegister(RegClass, MBBI, SPAdj);
   }
 
+  /// setUsed - Tell the scavenger a register is used.
+  ///
+  void setUsed(unsigned Reg);
 private:
-  /// restoreScavengedReg - Restore scavenged by loading it back from the
-  /// emergency spill slot. Mark it used.
-  void restoreScavengedReg();
+  /// isReserved - Returns true if a register is reserved. It is never "unused".
+  bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
 
-  MachineInstr *findFirstUse(MachineBasicBlock *MBB,
-                             MachineBasicBlock::iterator I, unsigned Reg,
-                             unsigned &Dist);
+  /// isUsed - Test if a register is currently being used.  When called by the
+  /// isAliasUsed function, we only check isReserved if this is the original
+  /// register, not an alias register.
+  ///
+  bool isUsed(unsigned Reg, bool CheckReserved = true) const   {
+    return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
+  }
+
+  /// isAliasUsed - Is Reg or an alias currently in use?
+  bool isAliasUsed(unsigned Reg) const;
+
+  /// setUsed / setUnused - Mark the state of one or a number of registers.
+  ///
+  void setUsed(BitVector &Regs) {
+    RegsAvailable.reset(Regs);
+  }
+  void setUnused(BitVector &Regs) {
+    RegsAvailable |= Regs;
+  }
 
   /// Add Reg and all its sub-registers to BV.
   void addRegWithSubRegs(BitVector &BV, unsigned Reg);
 
-  /// Add Reg and its aliases to BV.
-  void addRegWithAliases(BitVector &BV, unsigned Reg);
+  /// findSurvivorReg - Return the candidate register that is unused for the
+  /// longest after StartMI. UseMI is set to the instruction where the search
+  /// stopped.
+  ///
+  /// No more than InstrLimit instructions are inspected.
+  unsigned findSurvivorReg(MachineBasicBlock::iterator StartMI,
+                           BitVector &Candidates,
+                           unsigned InstrLimit,
+                           MachineBasicBlock::iterator &UseMI);
+
 };
 
 } // End llvm namespace