prepare for a change I'm about to make

[oota-llvm.git] / lib / CodeGen / VirtRegMap.h

diff --git a/lib/CodeGen/VirtRegMap.h b/lib/CodeGen/VirtRegMap.h
index b05c6ca5c9c9af49f9551f82ac8cc09914cc4261..426d1cf9b026246e039f3cd0407c363334c139a7 100644 (file)
--- a/lib/CodeGen/VirtRegMap.h
+++ b/lib/CodeGen/VirtRegMap.h
@@ -23,17 +23,35 @@
 
 namespace llvm {
   class MachineInstr;
+  class TargetInstrInfo;
 
   class VirtRegMap {
   public:
-    typedef std::multimap<MachineInstr*, unsigned> MI2VirtMapTy;
+    enum ModRef { isRef = 1, isMod = 2, isModRef = 3 };
+    typedef std::multimap<MachineInstr*,
+                          std::pair<unsigned, ModRef> > MI2VirtMapTy;
 
   private:
+    const TargetInstrInfo &TII;
+
     MachineFunction &MF;
+    /// Virt2PhysMap - This is a virtual to physical register
+    /// mapping. Each virtual register is required to have an entry in
+    /// it; even spilled virtual registers (the register mapped to a
+    /// spilled register is the temporary used to load it from the
+    /// stack).
     DenseMap<unsigned, VirtReg2IndexFunctor> Virt2PhysMap;
+    /// Virt2StackSlotMap - This is virtual register to stack slot
+    /// mapping. Each spilled virtual register has an entry in it
+    /// which corresponds to the stack slot this register is spilled
+    /// at.
     DenseMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap;
+    /// MI2VirtMap - This is MachineInstr to virtual register
+    /// mapping. In the case of memory spill code being folded into
+    /// instructions, we need to know which virtual register was
+    /// read/written by this instruction.
     MI2VirtMapTy MI2VirtMap;
-    
+
     VirtRegMap(const VirtRegMap&);     // DO NOT IMPLEMENT
     void operator=(const VirtRegMap&); // DO NOT IMPLEMENT
 
@@ -43,22 +61,25 @@ namespace llvm {
     };
 
   public:
-    VirtRegMap(MachineFunction &mf)
-      : MF(mf), Virt2PhysMap(NO_PHYS_REG), Virt2StackSlotMap(NO_STACK_SLOT) {
-      grow();
-    }
+    VirtRegMap(MachineFunction &mf);
 
     void grow();
 
+    /// @brief returns true if the specified virtual register is
+    /// mapped to a physical register
     bool hasPhys(unsigned virtReg) const {
       return getPhys(virtReg) != NO_PHYS_REG;
     }
 
+    /// @brief returns the physical register mapped to the specified
+    /// virtual register
     unsigned getPhys(unsigned virtReg) const {
       assert(MRegisterInfo::isVirtualRegister(virtReg));
       return Virt2PhysMap[virtReg];
     }
 
+    /// @brief creates a mapping for the specified virtual register to
+    /// the specified physical register
     void assignVirt2Phys(unsigned virtReg, unsigned physReg) {
       assert(MRegisterInfo::isVirtualRegister(virtReg) &&
              MRegisterInfo::isPhysicalRegister(physReg));
@@ -68,6 +89,8 @@ namespace llvm {
       Virt2PhysMap[virtReg] = physReg;
     }
 
+    /// @brief clears the specified virtual register's, physical
+    /// register mapping
     void clearVirt(unsigned virtReg) {
       assert(MRegisterInfo::isVirtualRegister(virtReg));
       assert(Virt2PhysMap[virtReg] != NO_PHYS_REG &&
@@ -75,30 +98,50 @@ namespace llvm {
       Virt2PhysMap[virtReg] = NO_PHYS_REG;
     }
 
+    /// @brief clears all virtual to physical register mappings
     void clearAllVirt() {
       Virt2PhysMap.clear();
       grow();
     }
 
+    /// @brief returns true is the specified virtual register is
+    /// mapped to a stack slot
     bool hasStackSlot(unsigned virtReg) const {
       return getStackSlot(virtReg) != NO_STACK_SLOT;
     }
 
+    /// @brief returns the stack slot mapped to the specified virtual
+    /// register
     int getStackSlot(unsigned virtReg) const {
       assert(MRegisterInfo::isVirtualRegister(virtReg));
       return Virt2StackSlotMap[virtReg];
     }
 
+    /// @brief create a mapping for the specifed virtual register to
+    /// the next available stack slot
     int assignVirt2StackSlot(unsigned virtReg);
+    /// @brief create a mapping for the specified virtual register to
+    /// the specified stack slot
     void assignVirt2StackSlot(unsigned virtReg, int frameIndex);
 
-    void virtFolded(unsigned virtReg, MachineInstr* oldMI,
-                    MachineInstr* newMI);
+    /// @brief Updates information about the specified virtual register's value
+    /// folded into newMI machine instruction.  The OpNum argument indicates the
+    /// operand number of OldMI that is folded.
+    void virtFolded(unsigned VirtReg, MachineInstr *OldMI, unsigned OpNum,
+                    MachineInstr *NewMI);
 
+    /// @brief returns the virtual registers' values folded in memory
+    /// operands of this instruction
     std::pair<MI2VirtMapTy::const_iterator, MI2VirtMapTy::const_iterator>
     getFoldedVirts(MachineInstr* MI) const {
       return MI2VirtMap.equal_range(MI);
     }
+    
+    /// RemoveFromFoldedVirtMap - If the specified machine instruction is in
+    /// the folded instruction map, remove its entry from the map.
+    void RemoveFromFoldedVirtMap(MachineInstr *MI) {
+      MI2VirtMap.erase(MI);
+    }
 
     void print(std::ostream &OS) const;
     void dump() const;
@@ -114,7 +157,7 @@ namespace llvm {
   struct Spiller {
     virtual ~Spiller();
     virtual bool runOnMachineFunction(MachineFunction &MF,
-                                      const VirtRegMap &VRM) = 0;
+                                      VirtRegMap &VRM) = 0;
   };
 
   /// createSpiller - Create an return a spiller object, as specified on the