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SparcV9RegInfo.h

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00001 //===-- SparcV9RegInfo.h - SparcV9 Target Register Info ---------*- C++ -*-===//
00002 // 
00003 //                     The LLVM Compiler Infrastructure
00004 //
00005 // This file was developed by the LLVM research group and is distributed under
00006 // the University of Illinois Open Source License. See LICENSE.TXT for details.
00007 // 
00008 //===----------------------------------------------------------------------===//
00009 //
00010 // This file is used to describe the register file of the SparcV9 target to
00011 // its register allocator.
00012 //
00013 //===----------------------------------------------------------------------===//
00014 
00015 #ifndef SPARCV9REGINFO_H
00016 #define SPARCV9REGINFO_H
00017 
00018 #include "llvm/ADT/hash_map"
00019 #include <string>
00020 #include <cassert>
00021 
00022 namespace llvm {
00023 
00024 class TargetMachine;
00025 class IGNode;
00026 class Type;
00027 class Value;
00028 class LiveRangeInfo;
00029 class Function;
00030 class LiveRange;
00031 class AddedInstrns;
00032 class MachineInstr;
00033 class BasicBlock;
00034 class SparcV9TargetMachine;
00035 
00036 
00037 ///----------------------------------------------------------------------------
00038 ///   Interface to description of machine register class (e.g., int reg class
00039 ///   float reg class etc)
00040 ///
00041 class TargetRegClassInfo {
00042 protected:
00043   const unsigned RegClassID;        // integer ID of a reg class
00044   const unsigned NumOfAvailRegs;    // # of avail for coloring -without SP etc.
00045   const unsigned NumOfAllRegs;      // # of all registers -including SP,g0 etc.
00046   
00047 public:
00048   inline unsigned getRegClassID()     const { return RegClassID; }
00049   inline unsigned getNumOfAvailRegs() const { return NumOfAvailRegs; }
00050   inline unsigned getNumOfAllRegs()   const { return NumOfAllRegs; }
00051 
00052   // This method marks the registers used for a given register number.
00053   // This defaults to marking a single register but may mark multiple
00054   // registers when a single number denotes paired registers.
00055   // 
00056   virtual void markColorsUsed(unsigned RegInClass,
00057                               int UserRegType,
00058                               int RegTypeWanted,
00059                               std::vector<bool> &IsColorUsedArr) const {
00060     assert(RegInClass < NumOfAllRegs && RegInClass < IsColorUsedArr.size());
00061     assert(UserRegType == RegTypeWanted &&
00062        "Default method is probably incorrect for class with multiple types.");
00063     IsColorUsedArr[RegInClass] = true;
00064   }
00065 
00066   // This method finds unused registers of the specified register type,
00067   // using the given "used" flag array IsColorUsedArr.  It defaults to
00068   // checking a single entry in the array directly, but that can be overridden
00069   // for paired registers and other such silliness.
00070   // It returns -1 if no unused color is found.
00071   // 
00072   virtual int findUnusedColor(int RegTypeWanted,
00073                           const std::vector<bool> &IsColorUsedArr) const {
00074     // find first unused color in the IsColorUsedArr directly
00075     unsigned NC = this->getNumOfAvailRegs();
00076     assert(IsColorUsedArr.size() >= NC && "Invalid colors-used array");
00077     for (unsigned c = 0; c < NC; c++)
00078       if (!IsColorUsedArr[c])
00079         return c;
00080     return -1;
00081   }
00082 
00083   // This method should find a color which is not used by neighbors
00084   // (i.e., a false position in IsColorUsedArr) and 
00085   virtual void colorIGNode(IGNode *Node,
00086                            const std::vector<bool> &IsColorUsedArr) const = 0;
00087 
00088   // Check whether a specific register is volatile, i.e., whether it is not
00089   // preserved across calls
00090   virtual bool isRegVolatile(int Reg) const = 0;
00091 
00092   // Check whether a specific register is modified as a side-effect of the
00093   // call instruction itself,
00094   virtual bool modifiedByCall(int Reg) const { return false; }
00095 
00096   virtual const char* const getRegName(unsigned reg) const = 0;
00097 
00098   TargetRegClassInfo(unsigned ID, unsigned NVR, unsigned NAR)
00099     : RegClassID(ID), NumOfAvailRegs(NVR), NumOfAllRegs(NAR) {}
00100 };
00101 
00102 /// SparcV9RegInfo - Interface to register info of SparcV9 target machine
00103 ///
00104 class SparcV9RegInfo {
00105   SparcV9RegInfo(const SparcV9RegInfo &);  // DO NOT IMPLEMENT
00106   void operator=(const SparcV9RegInfo &); // DO NOT IMPLEMENT
00107 protected:
00108   // A vector of all machine register classes
00109   //
00110   std::vector<const TargetRegClassInfo *> MachineRegClassArr;    
00111   
00112 public:
00113   const TargetMachine &target;
00114 
00115   // A register can be initialized to an invalid number. That number can
00116   // be obtained using this method.
00117   //
00118   static int getInvalidRegNum() { return -1; }
00119 
00120 
00121   // According the definition of a MachineOperand class, a Value in a
00122   // machine instruction can go into either a normal register or a 
00123   // condition code register. If isCCReg is true below, the ID of the condition
00124   // code register class will be returned. Otherwise, the normal register
00125   // class (eg. int, float) must be returned.
00126 
00127   // To find the register class used for a specified Type
00128   //
00129   unsigned getRegClassIDOfType  (const Type *type,
00130            bool isCCReg = false) const;
00131 
00132   // To find the register class to which a specified register belongs
00133   //
00134   unsigned getRegClassIDOfRegType(int regType) const;
00135 
00136   unsigned getRegClassIDOfReg(int unifiedRegNum) const {
00137     unsigned classId = 0;
00138     (void) getClassRegNum(unifiedRegNum, classId);
00139     return classId;
00140   }
00141 
00142   unsigned int getNumOfRegClasses() const { 
00143     return MachineRegClassArr.size(); 
00144   }  
00145 
00146   const TargetRegClassInfo *getMachineRegClass(unsigned i) const { 
00147     return MachineRegClassArr[i]; 
00148   }
00149 
00150   // getZeroRegNum - returns the register that is hardwired to always contain
00151   // zero, if any (-1 if none). This is the unified register number.
00152   //
00153   unsigned getZeroRegNum() const;
00154 
00155   // The following methods are used to color special live ranges (e.g.
00156   // method args and return values etc.) with specific hardware registers
00157   // as required. See SparcRegInfo.cpp for the implementation for Sparc.
00158   //
00159   void suggestRegs4MethodArgs(const Function *Func, 
00160                                       LiveRangeInfo& LRI) const;
00161 
00162   void suggestRegs4CallArgs(MachineInstr *CallI, 
00163                                     LiveRangeInfo& LRI) const;
00164 
00165   void suggestReg4RetValue(MachineInstr *RetI, 
00166            LiveRangeInfo& LRI) const;
00167 
00168   void colorMethodArgs(const Function *Func,
00169                            LiveRangeInfo &LRI,
00170                            std::vector<MachineInstr*>& InstrnsBefore,
00171                            std::vector<MachineInstr*>& InstrnsAfter) const;
00172 
00173 
00174   // Check whether a specific register is volatile, i.e., whether it is not
00175   // preserved across calls
00176   inline bool isRegVolatile(int RegClassID, int Reg) const {
00177     return MachineRegClassArr[RegClassID]->isRegVolatile(Reg);
00178   }
00179 
00180   // Check whether a specific register is modified as a side-effect of the
00181   // call instruction itself,
00182   inline bool modifiedByCall(int RegClassID, int Reg) const {
00183     return MachineRegClassArr[RegClassID]->modifiedByCall(Reg);
00184   }
00185   
00186   // getCallAddressReg - Returns the reg used for pushing the address
00187   // when a method is called. This can be used for other purposes
00188   // between calls
00189   //
00190   unsigned getCallAddressReg() const;
00191 
00192   // Each register class has a separate space for register IDs. To convert
00193   // a regId in a register class to a common Id, or vice versa,
00194   // we use the folloing two methods.
00195   //
00196   // This method converts from class reg. number to unified register number.
00197   int getUnifiedRegNum(unsigned regClassID, int reg) const {
00198     if (reg == getInvalidRegNum()) { return getInvalidRegNum(); }
00199     assert(regClassID < getNumOfRegClasses() && "Invalid register class");
00200     int totalRegs = 0;
00201     for (unsigned rcid = 0; rcid < regClassID; ++rcid)
00202       totalRegs += MachineRegClassArr[rcid]->getNumOfAllRegs();
00203     return reg + totalRegs;
00204   }
00205 
00206   // This method converts the unified number to the number in its class,
00207   // and returns the class ID in regClassID.
00208   int getClassRegNum(int uRegNum, unsigned& regClassID) const {
00209     if (uRegNum == getInvalidRegNum()) { return getInvalidRegNum(); }
00210     
00211     int totalRegs = 0, rcid = 0, NC = getNumOfRegClasses();  
00212     while (rcid < NC &&
00213            uRegNum>= totalRegs+(int)MachineRegClassArr[rcid]->getNumOfAllRegs())
00214     {
00215       totalRegs += MachineRegClassArr[rcid]->getNumOfAllRegs();
00216       rcid++;
00217     }
00218     if (rcid == NC) {
00219       assert(0 && "getClassRegNum(): Invalid register number");
00220       return getInvalidRegNum();
00221     }
00222     regClassID = rcid;
00223     return uRegNum - totalRegs;
00224   }
00225   
00226   // Returns the assembly-language name of the specified machine register.
00227   // 
00228   const char * const getUnifiedRegName(int UnifiedRegNum) const {
00229     unsigned regClassID = getNumOfRegClasses(); // initialize to invalid value
00230     int regNumInClass = getClassRegNum(UnifiedRegNum, regClassID);
00231     return MachineRegClassArr[regClassID]->getRegName(regNumInClass);
00232   }
00233 
00234   // This method gives the the number of bytes of stack space allocated 
00235   // to a register when it is spilled to the stack, according to its
00236   // register type.
00237   //
00238   // For SparcV9, currently we allocate 8 bytes on stack for all 
00239   // register types. We can optimize this later if necessary to save stack
00240   // space (However, should make sure that stack alignment is correct)
00241   //
00242   int getSpilledRegSize(int RegType) const {
00243     return 8;
00244   }
00245 
00246 private:
00247   // Number of registers used for passing int args (usually 6: %o0 - %o5)
00248   //
00249   unsigned const NumOfIntArgRegs;
00250 
00251   // Number of registers used for passing float args (usually 32: %f0 - %f31)
00252   //
00253   unsigned const NumOfFloatArgRegs;
00254 
00255   // The following methods are used to color special live ranges (e.g.
00256   // function args and return values etc.) with specific hardware registers
00257   // as required. See SparcV9RegInfo.cpp for the implementation.
00258   //
00259   void suggestReg4RetAddr(MachineInstr *RetMI, 
00260         LiveRangeInfo &LRI) const;
00261 
00262   void suggestReg4CallAddr(MachineInstr *CallMI, LiveRangeInfo &LRI) const;
00263   
00264   // Helper used by the all the getRegType() functions.
00265   int getRegTypeForClassAndType(unsigned regClassID, const Type* type) const;
00266 
00267 public:
00268   // Type of registers available in SparcV9. There can be several reg types
00269   // in the same class. For instace, the float reg class has Single/Double
00270   // types
00271   //
00272   enum RegTypes {
00273     IntRegType,
00274     FPSingleRegType,
00275     FPDoubleRegType,
00276     IntCCRegType,
00277     FloatCCRegType,
00278     SpecialRegType
00279   };
00280 
00281   // The actual register classes in the SparcV9
00282   //
00283   // **** WARNING: If this enum order is changed, also modify 
00284   // getRegisterClassOfValue method below since it assumes this particular 
00285   // order for efficiency.
00286   // 
00287   enum RegClassIDs { 
00288     IntRegClassID,                      // Integer
00289     FloatRegClassID,                    // Float (both single/double)
00290     IntCCRegClassID,                    // Int Condition Code
00291     FloatCCRegClassID,                  // Float Condition code
00292     SpecialRegClassID                   // Special (unallocated) registers
00293   };
00294 
00295   SparcV9RegInfo(const SparcV9TargetMachine &tgt);
00296 
00297   ~SparcV9RegInfo() {
00298     for (unsigned i = 0, e = MachineRegClassArr.size(); i != e; ++i)
00299       delete MachineRegClassArr[i];
00300   }
00301 
00302   // Returns the register containing the return address.
00303   // It should be made sure that this  register contains the return 
00304   // value when a return instruction is reached.
00305   //
00306   unsigned getReturnAddressReg() const;
00307 
00308   // Number of registers used for passing int args (usually 6: %o0 - %o5)
00309   // and float args (usually 32: %f0 - %f31)
00310   //
00311   unsigned const getNumOfIntArgRegs() const   { return NumOfIntArgRegs; }
00312   unsigned const getNumOfFloatArgRegs() const { return NumOfFloatArgRegs; }
00313   
00314   // Compute which register can be used for an argument, if any
00315   // 
00316   int regNumForIntArg(bool inCallee, bool isVarArgsCall,
00317                       unsigned argNo, unsigned& regClassId) const;
00318 
00319   int regNumForFPArg(unsigned RegType, bool inCallee, bool isVarArgsCall,
00320                      unsigned argNo, unsigned& regClassId) const;
00321   
00322 
00323   // method used for printing a register for debugging purposes
00324   //
00325   void printReg(const LiveRange *LR) const;
00326 
00327   // To obtain the return value and the indirect call address (if any)
00328   // contained in a CALL machine instruction
00329   //
00330   const Value * getCallInstRetVal(const MachineInstr *CallMI) const;
00331   const Value * getCallInstIndirectAddrVal(const MachineInstr *CallMI) const;
00332 
00333   // The following methods are used to generate "copy" machine instructions
00334   // for an architecture. Currently they are used in TargetRegClass 
00335   // interface. However, they can be moved to TargetInstrInfo interface if
00336   // necessary.
00337   //
00338   // The function regTypeNeedsScratchReg() can be used to check whether a
00339   // scratch register is needed to copy a register of type `regType' to
00340   // or from memory.  If so, such a scratch register can be provided by
00341   // the caller (e.g., if it knows which regsiters are free); otherwise
00342   // an arbitrary one will be chosen and spilled by the copy instructions.
00343   // If a scratch reg is needed, the reg. type that must be used
00344   // for scratch registers is returned in scratchRegType.
00345   //
00346 
00347   bool regTypeNeedsScratchReg(int RegType,
00348                               int& scratchRegClassId) const;
00349 
00350   void cpReg2RegMI(std::vector<MachineInstr*>& mvec,
00351                    unsigned SrcReg, unsigned DestReg,
00352                    int RegType) const;
00353 
00354   void cpReg2MemMI(std::vector<MachineInstr*>& mvec,
00355                    unsigned SrcReg, unsigned DestPtrReg,
00356                    int Offset, int RegType, int scratchReg = -1) const;
00357 
00358   void cpMem2RegMI(std::vector<MachineInstr*>& mvec,
00359                    unsigned SrcPtrReg, int Offset, unsigned DestReg,
00360                    int RegType, int scratchReg = -1) const;
00361 
00362   void cpValue2Value(Value *Src, Value *Dest,
00363                      std::vector<MachineInstr*>& mvec) const;
00364 
00365   // Get the register type for a register identified different ways.
00366   // Note that getRegTypeForLR(LR) != getRegTypeForDataType(LR->getType())!
00367   // The reg class of a LR depends both on the Value types in it and whether
00368   // they are CC registers or not (for example).
00369   int getRegTypeForDataType(const Type* type) const;
00370   int getRegTypeForLR(const LiveRange *LR) const;
00371   int getRegType(int unifiedRegNum) const;
00372 
00373   unsigned getFramePointer() const;
00374   unsigned getStackPointer() const;
00375 };
00376 
00377 } // End llvm namespace
00378 
00379 #endif // SPARCV9REGINFO_H