Added more comments

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1495 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Ruchira Sasanka 2002-01-07 19:57:37 +00:00
parent d00982a81c
commit 6011e2eead

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@ -79,6 +79,7 @@ public:
typedef hash_map<const MachineInstr *, AddedInstrns *> AddedInstrMapType;
// A vector of all machine register classes
//
typedef vector<const MachineRegClassInfo *> MachineRegClassArrayType;
@ -92,6 +93,10 @@ protected:
public:
// empty constructor
//
MachineRegInfo(const TargetMachine& tgt) : target(tgt) { }
// According the definition of a MachineOperand class, a Value in a
// machine instruction can go into either a normal register or a
@ -111,14 +116,14 @@ public:
}
// returns the register that is hardwired to zero if any (-1 if none)
virtual inline int getZeroRegNum() const = 0;
//virtual unsigned getRegClassIDOfValue (const Value *const Val) const = 0;
// this method must give the exact register class of a machine operand
// e.g, Int, Float, Int CC, Float CC
//virtual unsigned getRCIDOfMachineOp (const MachineOperand &MO) const = 0;
//
virtual inline int getZeroRegNum() const = 0;
// The following methods are used to color special live ranges (e.g.
// method args and return values etc.) with specific hardware registers
// as required. See SparcRegInfo.cpp for the implementation for Sparc.
//
virtual void suggestRegs4MethodArgs(const Method *const Meth,
LiveRangeInfo & LRI) const = 0;
@ -140,6 +145,11 @@ public:
// The following methods are used to generate "copy" machine instructions
// for an architecture. Currently they are used in MachineRegClass
// interface. However, they can be moved to MachineInstrInfo interface if
// necessary.
//
virtual MachineInstr *
cpReg2RegMI(const unsigned SrcReg, const unsigned DestReg,
const int RegType) const=0;
@ -154,44 +164,65 @@ public:
virtual MachineInstr *cpValue2Value( Value *Src, Value *Dest) const=0;
virtual bool isRegVolatile(const int RegClassID, const int Reg) const=0;
//virtual bool handleSpecialMInstr(const MachineInstr * MInst,
// LiveRangeInfo& LRI, vector<RegClass *> RCL) const = 0;
// returns the reg used for pushing the address when a method is called.
// Returns the reg used for pushing the address when a method is called.
// This can be used for other purposes between calls
//
virtual unsigned getCallAddressReg() const = 0;
// and when we return from a method. It should be made sure that this
// Returns the register containing the return address.
//It should be made sure that this
// register contains the return value when a return instruction is reached.
//
virtual unsigned getReturnAddressReg() const = 0;
// Each register class has a seperate space for register IDs. To convert
// a regId in a register class to a common Id, we use the folloing method(s)
//
virtual int getUnifiedRegNum(int RegClassID, int reg) const = 0;
virtual const string getUnifiedRegName(int UnifiedRegNum) const = 0;
// Gives the type of a register based on the type of the LR
//
virtual int getRegType(const LiveRange *const LR) const=0;
// Gives the return value contained in a CALL machine instruction
//
virtual const Value * getCallInstRetVal(const MachineInstr *CallMI) const=0;
// The following methods are used to get the frame/stack pointers
//
inline virtual unsigned getFramePointer() const=0;
inline virtual unsigned getStackPointer() const=0;
// A register can be initialized to an invalid number. That number can
// be obtained using this method.
//
inline virtual int getInvalidRegNum() const=0;
// Method for inserting caller saving code. The caller must save all the
// volatile registers across a call based on the calling conventions of
// an architecture. This must insert code for saving and restoring
// such registers on
//
virtual void insertCallerSavingCode(const MachineInstr *MInst,
const BasicBlock *BB,
PhyRegAlloc &PRA ) const = 0;
// This method gives the the number of bytes of stack spaceallocated
// to a register when it is spilled to the stack.
//
virtual inline int getSpilledRegSize(const int RegType) const = 0;
MachineRegInfo(const TargetMachine& tgt) : target(tgt) { }
};