| //===-- llvm/Target/TargetInstrInfo.h - Instruction Info --------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file describes the target machine instruction set to the code generator. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_TARGET_TARGETINSTRINFO_H |
| #define LLVM_TARGET_TARGETINSTRINFO_H |
| |
| #include "llvm/Target/TargetInstrDesc.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| |
| namespace llvm { |
| |
| class TargetAsmInfo; |
| class TargetRegisterClass; |
| class TargetRegisterInfo; |
| class LiveVariables; |
| class CalleeSavedInfo; |
| class SDNode; |
| class SelectionDAG; |
| |
| template<class T> class SmallVectorImpl; |
| |
| |
| //--------------------------------------------------------------------------- |
| /// |
| /// TargetInstrInfo - Interface to description of machine instruction set |
| /// |
| class TargetInstrInfo { |
| const TargetInstrDesc *Descriptors; // Raw array to allow static init'n |
| unsigned NumOpcodes; // Number of entries in the desc array |
| |
| TargetInstrInfo(const TargetInstrInfo &); // DO NOT IMPLEMENT |
| void operator=(const TargetInstrInfo &); // DO NOT IMPLEMENT |
| public: |
| TargetInstrInfo(const TargetInstrDesc *desc, unsigned NumOpcodes); |
| virtual ~TargetInstrInfo(); |
| |
| // Invariant opcodes: All instruction sets have these as their low opcodes. |
| enum { |
| PHI = 0, |
| INLINEASM = 1, |
| DBG_LABEL = 2, |
| EH_LABEL = 3, |
| GC_LABEL = 4, |
| DECLARE = 5, |
| |
| /// EXTRACT_SUBREG - This instruction takes two operands: a register |
| /// that has subregisters, and a subregister index. It returns the |
| /// extracted subregister value. This is commonly used to implement |
| /// truncation operations on target architectures which support it. |
| EXTRACT_SUBREG = 6, |
| |
| /// INSERT_SUBREG - This instruction takes three operands: a register |
| /// that has subregisters, a register providing an insert value, and a |
| /// subregister index. It returns the value of the first register with |
| /// the value of the second register inserted. The first register is |
| /// often defined by an IMPLICIT_DEF, as is commonly used to implement |
| /// anyext operations on target architectures which support it. |
| INSERT_SUBREG = 7, |
| |
| /// IMPLICIT_DEF - This is the MachineInstr-level equivalent of undef. |
| IMPLICIT_DEF = 8, |
| |
| /// SUBREG_TO_REG - This instruction is similar to INSERT_SUBREG except |
| /// that the first operand is an immediate integer constant. This constant |
| /// is often zero, as is commonly used to implement zext operations on |
| /// target architectures which support it, such as with x86-64 (with |
| /// zext from i32 to i64 via implicit zero-extension). |
| SUBREG_TO_REG = 9, |
| |
| /// COPY_TO_REGCLASS - This instruction is a placeholder for a plain |
| /// register-to-register copy into a specific register class. This is only |
| /// used between instruction selection and MachineInstr creation, before |
| /// virtual registers have been created for all the instructions, and it's |
| /// only needed in cases where the register classes implied by the |
| /// instructions are insufficient. The actual MachineInstrs to perform |
| /// the copy are emitted with the TargetInstrInfo::copyRegToReg hook. |
| COPY_TO_REGCLASS = 10 |
| }; |
| |
| unsigned getNumOpcodes() const { return NumOpcodes; } |
| |
| /// get - Return the machine instruction descriptor that corresponds to the |
| /// specified instruction opcode. |
| /// |
| const TargetInstrDesc &get(unsigned Opcode) const { |
| assert(Opcode < NumOpcodes && "Invalid opcode!"); |
| return Descriptors[Opcode]; |
| } |
| |
| /// isTriviallyReMaterializable - Return true if the instruction is trivially |
| /// rematerializable, meaning it has no side effects and requires no operands |
| /// that aren't always available. |
| bool isTriviallyReMaterializable(const MachineInstr *MI) const { |
| return MI->getDesc().isRematerializable() && |
| isReallyTriviallyReMaterializable(MI); |
| } |
| |
| protected: |
| /// isReallyTriviallyReMaterializable - For instructions with opcodes for |
| /// which the M_REMATERIALIZABLE flag is set, this function tests whether the |
| /// instruction itself is actually trivially rematerializable, considering |
| /// its operands. This is used for targets that have instructions that are |
| /// only trivially rematerializable for specific uses. This predicate must |
| /// return false if the instruction has any side effects other than |
| /// producing a value, or if it requres any address registers that are not |
| /// always available. |
| virtual bool isReallyTriviallyReMaterializable(const MachineInstr *MI) const { |
| return true; |
| } |
| |
| public: |
| /// Return true if the instruction is a register to register move and return |
| /// the source and dest operands and their sub-register indices by reference. |
| virtual bool isMoveInstr(const MachineInstr& MI, |
| unsigned& SrcReg, unsigned& DstReg, |
| unsigned& SrcSubIdx, unsigned& DstSubIdx) const { |
| return false; |
| } |
| |
| /// isLoadFromStackSlot - If the specified machine instruction is a direct |
| /// load from a stack slot, return the virtual or physical register number of |
| /// the destination along with the FrameIndex of the loaded stack slot. If |
| /// not, return 0. This predicate must return 0 if the instruction has |
| /// any side effects other than loading from the stack slot. |
| virtual unsigned isLoadFromStackSlot(const MachineInstr *MI, |
| int &FrameIndex) const { |
| return 0; |
| } |
| |
| /// isStoreToStackSlot - If the specified machine instruction is a direct |
| /// store to a stack slot, return the virtual or physical register number of |
| /// the source reg along with the FrameIndex of the loaded stack slot. If |
| /// not, return 0. This predicate must return 0 if the instruction has |
| /// any side effects other than storing to the stack slot. |
| virtual unsigned isStoreToStackSlot(const MachineInstr *MI, |
| int &FrameIndex) const { |
| return 0; |
| } |
| |
| /// reMaterialize - Re-issue the specified 'original' instruction at the |
| /// specific location targeting a new destination register. |
| virtual void reMaterialize(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| unsigned DestReg, unsigned SubIdx, |
| const MachineInstr *Orig) const = 0; |
| |
| /// isInvariantLoad - Return true if the specified instruction (which is |
| /// marked mayLoad) is loading from a location whose value is invariant across |
| /// the function. For example, loading a value from the constant pool or from |
| /// from the argument area of a function if it does not change. This should |
| /// only return true of *all* loads the instruction does are invariant (if it |
| /// does multiple loads). |
| virtual bool isInvariantLoad(const MachineInstr *MI) const { |
| return false; |
| } |
| |
| /// convertToThreeAddress - This method must be implemented by targets that |
| /// set the M_CONVERTIBLE_TO_3_ADDR flag. When this flag is set, the target |
| /// may be able to convert a two-address instruction into one or more true |
| /// three-address instructions on demand. This allows the X86 target (for |
| /// example) to convert ADD and SHL instructions into LEA instructions if they |
| /// would require register copies due to two-addressness. |
| /// |
| /// This method returns a null pointer if the transformation cannot be |
| /// performed, otherwise it returns the last new instruction. |
| /// |
| virtual MachineInstr * |
| convertToThreeAddress(MachineFunction::iterator &MFI, |
| MachineBasicBlock::iterator &MBBI, LiveVariables *LV) const { |
| return 0; |
| } |
| |
| /// commuteInstruction - If a target has any instructions that are commutable, |
| /// but require converting to a different instruction or making non-trivial |
| /// changes to commute them, this method can overloaded to do this. The |
| /// default implementation of this method simply swaps the first two operands |
| /// of MI and returns it. |
| /// |
| /// If a target wants to make more aggressive changes, they can construct and |
| /// return a new machine instruction. If an instruction cannot commute, it |
| /// can also return null. |
| /// |
| /// If NewMI is true, then a new machine instruction must be created. |
| /// |
| virtual MachineInstr *commuteInstruction(MachineInstr *MI, |
| bool NewMI = false) const = 0; |
| |
| /// findCommutedOpIndices - If specified MI is commutable, return the two |
| /// operand indices that would swap value. Return true if the instruction |
| /// is not in a form which this routine understands. |
| virtual bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1, |
| unsigned &SrcOpIdx2) const = 0; |
| |
| /// AnalyzeBranch - Analyze the branching code at the end of MBB, returning |
| /// true if it cannot be understood (e.g. it's a switch dispatch or isn't |
| /// implemented for a target). Upon success, this returns false and returns |
| /// with the following information in various cases: |
| /// |
| /// 1. If this block ends with no branches (it just falls through to its succ) |
| /// just return false, leaving TBB/FBB null. |
| /// 2. If this block ends with only an unconditional branch, it sets TBB to be |
| /// the destination block. |
| /// 3. If this block ends with an conditional branch and it falls through to |
| /// a successor block, it sets TBB to be the branch destination block and |
| /// a list of operands that evaluate the condition. These |
| /// operands can be passed to other TargetInstrInfo methods to create new |
| /// branches. |
| /// 4. If this block ends with a conditional branch followed by an |
| /// unconditional branch, it returns the 'true' destination in TBB, the |
| /// 'false' destination in FBB, and a list of operands that evaluate the |
| /// condition. These operands can be passed to other TargetInstrInfo |
| /// methods to create new branches. |
| /// |
| /// Note that RemoveBranch and InsertBranch must be implemented to support |
| /// cases where this method returns success. |
| /// |
| /// If AllowModify is true, then this routine is allowed to modify the basic |
| /// block (e.g. delete instructions after the unconditional branch). |
| /// |
| virtual bool AnalyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, |
| MachineBasicBlock *&FBB, |
| SmallVectorImpl<MachineOperand> &Cond, |
| bool AllowModify = false) const { |
| return true; |
| } |
| |
| /// RemoveBranch - Remove the branching code at the end of the specific MBB. |
| /// This is only invoked in cases where AnalyzeBranch returns success. It |
| /// returns the number of instructions that were removed. |
| virtual unsigned RemoveBranch(MachineBasicBlock &MBB) const { |
| assert(0 && "Target didn't implement TargetInstrInfo::RemoveBranch!"); |
| return 0; |
| } |
| |
| /// InsertBranch - Insert branch code into the end of the specified |
| /// MachineBasicBlock. The operands to this method are the same as those |
| /// returned by AnalyzeBranch. This is only invoked in cases where |
| /// AnalyzeBranch returns success. It returns the number of instructions |
| /// inserted. |
| /// |
| /// It is also invoked by tail merging to add unconditional branches in |
| /// cases where AnalyzeBranch doesn't apply because there was no original |
| /// branch to analyze. At least this much must be implemented, else tail |
| /// merging needs to be disabled. |
| virtual unsigned InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, |
| MachineBasicBlock *FBB, |
| const SmallVectorImpl<MachineOperand> &Cond) const { |
| assert(0 && "Target didn't implement TargetInstrInfo::InsertBranch!"); |
| return 0; |
| } |
| |
| /// copyRegToReg - Emit instructions to copy between a pair of registers. It |
| /// returns false if the target does not how to copy between the specified |
| /// registers. |
| virtual bool copyRegToReg(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| unsigned DestReg, unsigned SrcReg, |
| const TargetRegisterClass *DestRC, |
| const TargetRegisterClass *SrcRC) const { |
| assert(0 && "Target didn't implement TargetInstrInfo::copyRegToReg!"); |
| return false; |
| } |
| |
| /// storeRegToStackSlot - Store the specified register of the given register |
| /// class to the specified stack frame index. The store instruction is to be |
| /// added to the given machine basic block before the specified machine |
| /// instruction. If isKill is true, the register operand is the last use and |
| /// must be marked kill. |
| virtual void storeRegToStackSlot(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| unsigned SrcReg, bool isKill, int FrameIndex, |
| const TargetRegisterClass *RC) const { |
| assert(0 && "Target didn't implement TargetInstrInfo::storeRegToStackSlot!"); |
| } |
| |
| /// loadRegFromStackSlot - Load the specified register of the given register |
| /// class from the specified stack frame index. The load instruction is to be |
| /// added to the given machine basic block before the specified machine |
| /// instruction. |
| virtual void loadRegFromStackSlot(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| unsigned DestReg, int FrameIndex, |
| const TargetRegisterClass *RC) const { |
| assert(0 && "Target didn't implement TargetInstrInfo::loadRegFromStackSlot!"); |
| } |
| |
| /// spillCalleeSavedRegisters - Issues instruction(s) to spill all callee |
| /// saved registers and returns true if it isn't possible / profitable to do |
| /// so by issuing a series of store instructions via |
| /// storeRegToStackSlot(). Returns false otherwise. |
| virtual bool spillCalleeSavedRegisters(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| const std::vector<CalleeSavedInfo> &CSI) const { |
| return false; |
| } |
| |
| /// restoreCalleeSavedRegisters - Issues instruction(s) to restore all callee |
| /// saved registers and returns true if it isn't possible / profitable to do |
| /// so by issuing a series of load instructions via loadRegToStackSlot(). |
| /// Returns false otherwise. |
| virtual bool restoreCalleeSavedRegisters(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| const std::vector<CalleeSavedInfo> &CSI) const { |
| return false; |
| } |
| |
| /// foldMemoryOperand - Attempt to fold a load or store of the specified stack |
| /// slot into the specified machine instruction for the specified operand(s). |
| /// If this is possible, a new instruction is returned with the specified |
| /// operand folded, otherwise NULL is returned. The client is responsible for |
| /// removing the old instruction and adding the new one in the instruction |
| /// stream. |
| MachineInstr* foldMemoryOperand(MachineFunction &MF, |
| MachineInstr* MI, |
| const SmallVectorImpl<unsigned> &Ops, |
| int FrameIndex) const; |
| |
| /// foldMemoryOperand - Same as the previous version except it allows folding |
| /// of any load and store from / to any address, not just from a specific |
| /// stack slot. |
| MachineInstr* foldMemoryOperand(MachineFunction &MF, |
| MachineInstr* MI, |
| const SmallVectorImpl<unsigned> &Ops, |
| MachineInstr* LoadMI) const; |
| |
| protected: |
| /// foldMemoryOperandImpl - Target-dependent implementation for |
| /// foldMemoryOperand. Target-independent code in foldMemoryOperand will |
| /// take care of adding a MachineMemOperand to the newly created instruction. |
| virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF, |
| MachineInstr* MI, |
| const SmallVectorImpl<unsigned> &Ops, |
| int FrameIndex) const { |
| return 0; |
| } |
| |
| /// foldMemoryOperandImpl - Target-dependent implementation for |
| /// foldMemoryOperand. Target-independent code in foldMemoryOperand will |
| /// take care of adding a MachineMemOperand to the newly created instruction. |
| virtual MachineInstr* foldMemoryOperandImpl(MachineFunction &MF, |
| MachineInstr* MI, |
| const SmallVectorImpl<unsigned> &Ops, |
| MachineInstr* LoadMI) const { |
| return 0; |
| } |
| |
| public: |
| /// canFoldMemoryOperand - Returns true for the specified load / store if |
| /// folding is possible. |
| virtual |
| bool canFoldMemoryOperand(const MachineInstr *MI, |
| const SmallVectorImpl<unsigned> &Ops) const { |
| return false; |
| } |
| |
| /// unfoldMemoryOperand - Separate a single instruction which folded a load or |
| /// a store or a load and a store into two or more instruction. If this is |
| /// possible, returns true as well as the new instructions by reference. |
| virtual bool unfoldMemoryOperand(MachineFunction &MF, MachineInstr *MI, |
| unsigned Reg, bool UnfoldLoad, bool UnfoldStore, |
| SmallVectorImpl<MachineInstr*> &NewMIs) const{ |
| return false; |
| } |
| |
| virtual bool unfoldMemoryOperand(SelectionDAG &DAG, SDNode *N, |
| SmallVectorImpl<SDNode*> &NewNodes) const { |
| return false; |
| } |
| |
| /// getOpcodeAfterMemoryUnfold - Returns the opcode of the would be new |
| /// instruction after load / store are unfolded from an instruction of the |
| /// specified opcode. It returns zero if the specified unfolding is not |
| /// possible. |
| virtual unsigned getOpcodeAfterMemoryUnfold(unsigned Opc, |
| bool UnfoldLoad, bool UnfoldStore) const { |
| return 0; |
| } |
| |
| /// BlockHasNoFallThrough - Return true if the specified block does not |
| /// fall-through into its successor block. This is primarily used when a |
| /// branch is unanalyzable. It is useful for things like unconditional |
| /// indirect branches (jump tables). |
| virtual bool BlockHasNoFallThrough(const MachineBasicBlock &MBB) const { |
| return false; |
| } |
| |
| /// ReverseBranchCondition - Reverses the branch condition of the specified |
| /// condition list, returning false on success and true if it cannot be |
| /// reversed. |
| virtual |
| bool ReverseBranchCondition(SmallVectorImpl<MachineOperand> &Cond) const { |
| return true; |
| } |
| |
| /// insertNoop - Insert a noop into the instruction stream at the specified |
| /// point. |
| virtual void insertNoop(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI) const; |
| |
| /// isPredicated - Returns true if the instruction is already predicated. |
| /// |
| virtual bool isPredicated(const MachineInstr *MI) const { |
| return false; |
| } |
| |
| /// isUnpredicatedTerminator - Returns true if the instruction is a |
| /// terminator instruction that has not been predicated. |
| virtual bool isUnpredicatedTerminator(const MachineInstr *MI) const; |
| |
| /// PredicateInstruction - Convert the instruction into a predicated |
| /// instruction. It returns true if the operation was successful. |
| virtual |
| bool PredicateInstruction(MachineInstr *MI, |
| const SmallVectorImpl<MachineOperand> &Pred) const = 0; |
| |
| /// SubsumesPredicate - Returns true if the first specified predicate |
| /// subsumes the second, e.g. GE subsumes GT. |
| virtual |
| bool SubsumesPredicate(const SmallVectorImpl<MachineOperand> &Pred1, |
| const SmallVectorImpl<MachineOperand> &Pred2) const { |
| return false; |
| } |
| |
| /// DefinesPredicate - If the specified instruction defines any predicate |
| /// or condition code register(s) used for predication, returns true as well |
| /// as the definition predicate(s) by reference. |
| virtual bool DefinesPredicate(MachineInstr *MI, |
| std::vector<MachineOperand> &Pred) const { |
| return false; |
| } |
| |
| /// isSafeToMoveRegClassDefs - Return true if it's safe to move a machine |
| /// instruction that defines the specified register class. |
| virtual bool isSafeToMoveRegClassDefs(const TargetRegisterClass *RC) const { |
| return true; |
| } |
| |
| /// isDeadInstruction - Return true if the instruction is considered dead. |
| /// This allows some late codegen passes to delete them. |
| virtual bool isDeadInstruction(const MachineInstr *MI) const = 0; |
| |
| /// GetInstSize - Returns the size of the specified Instruction. |
| /// |
| virtual unsigned GetInstSizeInBytes(const MachineInstr *MI) const { |
| assert(0 && "Target didn't implement TargetInstrInfo::GetInstSize!"); |
| return 0; |
| } |
| |
| /// GetFunctionSizeInBytes - Returns the size of the specified |
| /// MachineFunction. |
| /// |
| virtual unsigned GetFunctionSizeInBytes(const MachineFunction &MF) const = 0; |
| |
| /// Measure the specified inline asm to determine an approximation of its |
| /// length. |
| virtual unsigned getInlineAsmLength(const char *Str, |
| const TargetAsmInfo &TAI) const; |
| }; |
| |
| /// TargetInstrInfoImpl - This is the default implementation of |
| /// TargetInstrInfo, which just provides a couple of default implementations |
| /// for various methods. This separated out because it is implemented in |
| /// libcodegen, not in libtarget. |
| class TargetInstrInfoImpl : public TargetInstrInfo { |
| protected: |
| TargetInstrInfoImpl(const TargetInstrDesc *desc, unsigned NumOpcodes) |
| : TargetInstrInfo(desc, NumOpcodes) {} |
| public: |
| virtual MachineInstr *commuteInstruction(MachineInstr *MI, |
| bool NewMI = false) const; |
| virtual bool findCommutedOpIndices(MachineInstr *MI, unsigned &SrcOpIdx1, |
| unsigned &SrcOpIdx2) const; |
| virtual bool PredicateInstruction(MachineInstr *MI, |
| const SmallVectorImpl<MachineOperand> &Pred) const; |
| virtual void reMaterialize(MachineBasicBlock &MBB, |
| MachineBasicBlock::iterator MI, |
| unsigned DestReg, unsigned SubReg, |
| const MachineInstr *Orig) const; |
| virtual bool isDeadInstruction(const MachineInstr *MI) const; |
| |
| virtual unsigned GetFunctionSizeInBytes(const MachineFunction &MF) const; |
| }; |
| |
| } // End llvm namespace |
| |
| #endif |