//===- MipsInstrInfo.cpp - Mips Instruction Information -------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file contains the Mips implementation of the TargetInstrInfo class. // //===----------------------------------------------------------------------===// #include "MipsInstrInfo.h" #include "MCTargetDesc/MipsBaseInfo.h" #include "MCTargetDesc/MipsMCTargetDesc.h" #include "MipsSubtarget.h" #include "llvm/ADT/SmallVector.h" #include "llvm/CodeGen/MachineBasicBlock.h" #include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/CodeGen/MachineFunction.h" #include "llvm/CodeGen/MachineInstr.h" #include "llvm/CodeGen/MachineInstrBuilder.h" #include "llvm/CodeGen/MachineOperand.h" #include "llvm/CodeGen/TargetOpcodes.h" #include "llvm/CodeGen/TargetSubtargetInfo.h" #include "llvm/IR/DebugLoc.h" #include "llvm/MC/MCInstrDesc.h" #include "llvm/Target/TargetMachine.h" #include using namespace llvm; #define GET_INSTRINFO_CTOR_DTOR #include "MipsGenInstrInfo.inc" // Pin the vtable to this file. void MipsInstrInfo::anchor() {} MipsInstrInfo::MipsInstrInfo(const MipsSubtarget &STI, unsigned UncondBr) : MipsGenInstrInfo(Mips::ADJCALLSTACKDOWN, Mips::ADJCALLSTACKUP), Subtarget(STI), UncondBrOpc(UncondBr) {} const MipsInstrInfo *MipsInstrInfo::create(MipsSubtarget &STI) { if (STI.inMips16Mode()) return createMips16InstrInfo(STI); return createMipsSEInstrInfo(STI); } bool MipsInstrInfo::isZeroImm(const MachineOperand &op) const { return op.isImm() && op.getImm() == 0; } /// insertNoop - If data hazard condition is found insert the target nop /// instruction. // FIXME: This appears to be dead code. void MipsInstrInfo:: insertNoop(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI) const { DebugLoc DL; BuildMI(MBB, MI, DL, get(Mips::NOP)); } MachineMemOperand * MipsInstrInfo::GetMemOperand(MachineBasicBlock &MBB, int FI, MachineMemOperand::Flags Flags) const { MachineFunction &MF = *MBB.getParent(); MachineFrameInfo &MFI = MF.getFrameInfo(); unsigned Align = MFI.getObjectAlignment(FI); return MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(MF, FI), Flags, MFI.getObjectSize(FI), Align); } //===----------------------------------------------------------------------===// // Branch Analysis //===----------------------------------------------------------------------===// void MipsInstrInfo::AnalyzeCondBr(const MachineInstr *Inst, unsigned Opc, MachineBasicBlock *&BB, SmallVectorImpl &Cond) const { assert(getAnalyzableBrOpc(Opc) && "Not an analyzable branch"); int NumOp = Inst->getNumExplicitOperands(); // for both int and fp branches, the last explicit operand is the // MBB. BB = Inst->getOperand(NumOp-1).getMBB(); Cond.push_back(MachineOperand::CreateImm(Opc)); for (int i = 0; i < NumOp-1; i++) Cond.push_back(Inst->getOperand(i)); } bool MipsInstrInfo::analyzeBranch(MachineBasicBlock &MBB, MachineBasicBlock *&TBB, MachineBasicBlock *&FBB, SmallVectorImpl &Cond, bool AllowModify) const { SmallVector BranchInstrs; BranchType BT = analyzeBranch(MBB, TBB, FBB, Cond, AllowModify, BranchInstrs); return (BT == BT_None) || (BT == BT_Indirect); } void MipsInstrInfo::BuildCondBr(MachineBasicBlock &MBB, MachineBasicBlock *TBB, const DebugLoc &DL, ArrayRef Cond) const { unsigned Opc = Cond[0].getImm(); const MCInstrDesc &MCID = get(Opc); MachineInstrBuilder MIB = BuildMI(&MBB, DL, MCID); for (unsigned i = 1; i < Cond.size(); ++i) { assert((Cond[i].isImm() || Cond[i].isReg()) && "Cannot copy operand for conditional branch!"); MIB.add(Cond[i]); } MIB.addMBB(TBB); } unsigned MipsInstrInfo::insertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, MachineBasicBlock *FBB, ArrayRef Cond, const DebugLoc &DL, int *BytesAdded) const { // Shouldn't be a fall through. assert(TBB && "insertBranch must not be told to insert a fallthrough"); assert(!BytesAdded && "code size not handled"); // # of condition operands: // Unconditional branches: 0 // Floating point branches: 1 (opc) // Int BranchZero: 2 (opc, reg) // Int Branch: 3 (opc, reg0, reg1) assert((Cond.size() <= 3) && "# of Mips branch conditions must be <= 3!"); // Two-way Conditional branch. if (FBB) { BuildCondBr(MBB, TBB, DL, Cond); BuildMI(&MBB, DL, get(UncondBrOpc)).addMBB(FBB); return 2; } // One way branch. // Unconditional branch. if (Cond.empty()) BuildMI(&MBB, DL, get(UncondBrOpc)).addMBB(TBB); else // Conditional branch. BuildCondBr(MBB, TBB, DL, Cond); return 1; } unsigned MipsInstrInfo::removeBranch(MachineBasicBlock &MBB, int *BytesRemoved) const { assert(!BytesRemoved && "code size not handled"); MachineBasicBlock::reverse_iterator I = MBB.rbegin(), REnd = MBB.rend(); unsigned removed = 0; // Up to 2 branches are removed. // Note that indirect branches are not removed. while (I != REnd && removed < 2) { // Skip past debug instructions. if (I->isDebugValue()) { ++I; continue; } if (!getAnalyzableBrOpc(I->getOpcode())) break; // Remove the branch. I->eraseFromParent(); I = MBB.rbegin(); ++removed; } return removed; } /// reverseBranchCondition - Return the inverse opcode of the /// specified Branch instruction. bool MipsInstrInfo::reverseBranchCondition( SmallVectorImpl &Cond) const { assert( (Cond.size() && Cond.size() <= 3) && "Invalid Mips branch condition!"); Cond[0].setImm(getOppositeBranchOpc(Cond[0].getImm())); return false; } MipsInstrInfo::BranchType MipsInstrInfo::analyzeBranch( MachineBasicBlock &MBB, MachineBasicBlock *&TBB, MachineBasicBlock *&FBB, SmallVectorImpl &Cond, bool AllowModify, SmallVectorImpl &BranchInstrs) const { MachineBasicBlock::reverse_iterator I = MBB.rbegin(), REnd = MBB.rend(); // Skip all the debug instructions. while (I != REnd && I->isDebugValue()) ++I; if (I == REnd || !isUnpredicatedTerminator(*I)) { // This block ends with no branches (it just falls through to its succ). // Leave TBB/FBB null. TBB = FBB = nullptr; return BT_NoBranch; } MachineInstr *LastInst = &*I; unsigned LastOpc = LastInst->getOpcode(); BranchInstrs.push_back(LastInst); // Not an analyzable branch (e.g., indirect jump). if (!getAnalyzableBrOpc(LastOpc)) return LastInst->isIndirectBranch() ? BT_Indirect : BT_None; // Get the second to last instruction in the block. unsigned SecondLastOpc = 0; MachineInstr *SecondLastInst = nullptr; // Skip past any debug instruction to see if the second last actual // is a branch. ++I; while (I != REnd && I->isDebugValue()) ++I; if (I != REnd) { SecondLastInst = &*I; SecondLastOpc = getAnalyzableBrOpc(SecondLastInst->getOpcode()); // Not an analyzable branch (must be an indirect jump). if (isUnpredicatedTerminator(*SecondLastInst) && !SecondLastOpc) return BT_None; } // If there is only one terminator instruction, process it. if (!SecondLastOpc) { // Unconditional branch. if (LastInst->isUnconditionalBranch()) { TBB = LastInst->getOperand(0).getMBB(); return BT_Uncond; } // Conditional branch AnalyzeCondBr(LastInst, LastOpc, TBB, Cond); return BT_Cond; } // If we reached here, there are two branches. // If there are three terminators, we don't know what sort of block this is. if (++I != REnd && isUnpredicatedTerminator(*I)) return BT_None; BranchInstrs.insert(BranchInstrs.begin(), SecondLastInst); // If second to last instruction is an unconditional branch, // analyze it and remove the last instruction. if (SecondLastInst->isUnconditionalBranch()) { // Return if the last instruction cannot be removed. if (!AllowModify) return BT_None; TBB = SecondLastInst->getOperand(0).getMBB(); LastInst->eraseFromParent(); BranchInstrs.pop_back(); return BT_Uncond; } // Conditional branch followed by an unconditional branch. // The last one must be unconditional. if (!LastInst->isUnconditionalBranch()) return BT_None; AnalyzeCondBr(SecondLastInst, SecondLastOpc, TBB, Cond); FBB = LastInst->getOperand(0).getMBB(); return BT_CondUncond; } /// Return the corresponding compact (no delay slot) form of a branch. unsigned MipsInstrInfo::getEquivalentCompactForm( const MachineBasicBlock::iterator I) const { unsigned Opcode = I->getOpcode(); bool canUseShortMicroMipsCTI = false; if (Subtarget.inMicroMipsMode()) { switch (Opcode) { case Mips::BNE: case Mips::BNE_MM: case Mips::BEQ: case Mips::BEQ_MM: // microMIPS has NE,EQ branches that do not have delay slots provided one // of the operands is zero. if (I->getOperand(1).getReg() == Subtarget.getABI().GetZeroReg()) canUseShortMicroMipsCTI = true; break; // For microMIPS the PseudoReturn and PseudoIndirectBranch are always // expanded to JR_MM, so they can be replaced with JRC16_MM. case Mips::JR: case Mips::PseudoReturn: case Mips::PseudoIndirectBranch: canUseShortMicroMipsCTI = true; break; } } // MIPSR6 forbids both operands being the zero register. if (Subtarget.hasMips32r6() && (I->getNumOperands() > 1) && (I->getOperand(0).isReg() && (I->getOperand(0).getReg() == Mips::ZERO || I->getOperand(0).getReg() == Mips::ZERO_64)) && (I->getOperand(1).isReg() && (I->getOperand(1).getReg() == Mips::ZERO || I->getOperand(1).getReg() == Mips::ZERO_64))) return 0; if (Subtarget.hasMips32r6() || canUseShortMicroMipsCTI) { switch (Opcode) { case Mips::B: return Mips::BC; case Mips::BAL: return Mips::BALC; case Mips::BEQ: case Mips::BEQ_MM: if (canUseShortMicroMipsCTI) return Mips::BEQZC_MM; else if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BEQC; case Mips::BNE: case Mips::BNE_MM: if (canUseShortMicroMipsCTI) return Mips::BNEZC_MM; else if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BNEC; case Mips::BGE: if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BGEC; case Mips::BGEU: if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BGEUC; case Mips::BGEZ: return Mips::BGEZC; case Mips::BGTZ: return Mips::BGTZC; case Mips::BLEZ: return Mips::BLEZC; case Mips::BLT: if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BLTC; case Mips::BLTU: if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BLTUC; case Mips::BLTZ: return Mips::BLTZC; case Mips::BEQ64: if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BEQC64; case Mips::BNE64: if (I->getOperand(0).getReg() == I->getOperand(1).getReg()) return 0; return Mips::BNEC64; case Mips::BGTZ64: return Mips::BGTZC64; case Mips::BGEZ64: return Mips::BGEZC64; case Mips::BLTZ64: return Mips::BLTZC64; case Mips::BLEZ64: return Mips::BLEZC64; // For MIPSR6, the instruction 'jic' can be used for these cases. Some // tools will accept 'jrc reg' as an alias for 'jic 0, $reg'. case Mips::JR: case Mips::PseudoIndirectBranchR6: case Mips::PseudoReturn: case Mips::TAILCALLR6REG: if (canUseShortMicroMipsCTI) return Mips::JRC16_MM; return Mips::JIC; case Mips::JALRPseudo: return Mips::JIALC; case Mips::JR64: case Mips::PseudoIndirectBranch64R6: case Mips::PseudoReturn64: case Mips::TAILCALL64R6REG: return Mips::JIC64; case Mips::JALR64Pseudo: return Mips::JIALC64; default: return 0; } } return 0; } /// Predicate for distingushing between control transfer instructions and all /// other instructions for handling forbidden slots. Consider inline assembly /// as unsafe as well. bool MipsInstrInfo::SafeInForbiddenSlot(const MachineInstr &MI) const { if (MI.isInlineAsm()) return false; return (MI.getDesc().TSFlags & MipsII::IsCTI) == 0; } /// Predicate for distingushing instructions that have forbidden slots. bool MipsInstrInfo::HasForbiddenSlot(const MachineInstr &MI) const { return (MI.getDesc().TSFlags & MipsII::HasForbiddenSlot) != 0; } /// Return the number of bytes of code the specified instruction may be. unsigned MipsInstrInfo::getInstSizeInBytes(const MachineInstr &MI) const { switch (MI.getOpcode()) { default: return MI.getDesc().getSize(); case TargetOpcode::INLINEASM: { // Inline Asm: Variable size. const MachineFunction *MF = MI.getParent()->getParent(); const char *AsmStr = MI.getOperand(0).getSymbolName(); return getInlineAsmLength(AsmStr, *MF->getTarget().getMCAsmInfo()); } case Mips::CONSTPOOL_ENTRY: // If this machine instr is a constant pool entry, its size is recorded as // operand #2. return MI.getOperand(2).getImm(); } } MachineInstrBuilder MipsInstrInfo::genInstrWithNewOpc(unsigned NewOpc, MachineBasicBlock::iterator I) const { MachineInstrBuilder MIB; // Certain branches have two forms: e.g beq $1, $zero, dest vs beqz $1, dest // Pick the zero form of the branch for readable assembly and for greater // branch distance in non-microMIPS mode. // Additional MIPSR6 does not permit the use of register $zero for compact // branches. // FIXME: Certain atomic sequences on mips64 generate 32bit references to // Mips::ZERO, which is incorrect. This test should be updated to use // Subtarget.getABI().GetZeroReg() when those atomic sequences and others // are fixed. int ZeroOperandPosition = -1; bool BranchWithZeroOperand = false; if (I->isBranch() && !I->isPseudo()) { auto TRI = I->getParent()->getParent()->getSubtarget().getRegisterInfo(); ZeroOperandPosition = I->findRegisterUseOperandIdx(Mips::ZERO, false, TRI); BranchWithZeroOperand = ZeroOperandPosition != -1; } if (BranchWithZeroOperand) { switch (NewOpc) { case Mips::BEQC: NewOpc = Mips::BEQZC; break; case Mips::BNEC: NewOpc = Mips::BNEZC; break; case Mips::BGEC: NewOpc = Mips::BGEZC; break; case Mips::BLTC: NewOpc = Mips::BLTZC; break; case Mips::BEQC64: NewOpc = Mips::BEQZC64; break; case Mips::BNEC64: NewOpc = Mips::BNEZC64; break; } } MIB = BuildMI(*I->getParent(), I, I->getDebugLoc(), get(NewOpc)); // For MIPSR6 JI*C requires an immediate 0 as an operand, JIALC(64) an // immediate 0 as an operand and requires the removal of it's implicit-def %ra // implicit operand as copying the implicit operations of the instructio we're // looking at will give us the correct flags. if (NewOpc == Mips::JIC || NewOpc == Mips::JIALC || NewOpc == Mips::JIC64 || NewOpc == Mips::JIALC64) { if (NewOpc == Mips::JIALC || NewOpc == Mips::JIALC64) MIB->RemoveOperand(0); for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) { MIB.add(I->getOperand(J)); } MIB.addImm(0); } else { for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) { if (BranchWithZeroOperand && (unsigned)ZeroOperandPosition == J) continue; MIB.add(I->getOperand(J)); } } MIB.copyImplicitOps(*I); MIB.setMemRefs(I->memoperands_begin(), I->memoperands_end()); return MIB; } bool MipsInstrInfo::findCommutedOpIndices(MachineInstr &MI, unsigned &SrcOpIdx1, unsigned &SrcOpIdx2) const { assert(!MI.isBundle() && "TargetInstrInfo::findCommutedOpIndices() can't handle bundles"); const MCInstrDesc &MCID = MI.getDesc(); if (!MCID.isCommutable()) return false; switch (MI.getOpcode()) { case Mips::DPADD_U_H: case Mips::DPADD_U_W: case Mips::DPADD_U_D: case Mips::DPADD_S_H: case Mips::DPADD_S_W: case Mips::DPADD_S_D: // The first operand is both input and output, so it should not commute if (!fixCommutedOpIndices(SrcOpIdx1, SrcOpIdx2, 2, 3)) return false; if (!MI.getOperand(SrcOpIdx1).isReg() || !MI.getOperand(SrcOpIdx2).isReg()) return false; return true; } return TargetInstrInfo::findCommutedOpIndices(MI, SrcOpIdx1, SrcOpIdx2); } // ins, ext, dext*, dins have the following constraints: // X <= pos < Y // X < size <= Y // X < pos+size <= Y // // dinsm and dinsu have the following constraints: // X <= pos < Y // X <= size <= Y // X < pos+size <= Y // // The callee of verifyInsExtInstruction however gives the bounds of // dins[um] like the other (d)ins (d)ext(um) instructions, so that this // function doesn't have to vary it's behaviour based on the instruction // being checked. static bool verifyInsExtInstruction(const MachineInstr &MI, StringRef &ErrInfo, const int64_t PosLow, const int64_t PosHigh, const int64_t SizeLow, const int64_t SizeHigh, const int64_t BothLow, const int64_t BothHigh) { MachineOperand MOPos = MI.getOperand(2); if (!MOPos.isImm()) { ErrInfo = "Position is not an immediate!"; return false; } int64_t Pos = MOPos.getImm(); if (!((PosLow <= Pos) && (Pos < PosHigh))) { ErrInfo = "Position operand is out of range!"; return false; } MachineOperand MOSize = MI.getOperand(3); if (!MOSize.isImm()) { ErrInfo = "Size operand is not an immediate!"; return false; } int64_t Size = MOSize.getImm(); if (!((SizeLow < Size) && (Size <= SizeHigh))) { ErrInfo = "Size operand is out of range!"; return false; } if (!((BothLow < (Pos + Size)) && ((Pos + Size) <= BothHigh))) { ErrInfo = "Position + Size is out of range!"; return false; } return true; } // Perform target specific instruction verification. bool MipsInstrInfo::verifyInstruction(const MachineInstr &MI, StringRef &ErrInfo) const { // Verify that ins and ext instructions are well formed. switch (MI.getOpcode()) { case Mips::EXT: case Mips::EXT_MM: case Mips::INS: case Mips::INS_MM: case Mips::DINS: return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 0, 32, 0, 32); case Mips::DINSM: // The ISA spec has a subtle difference difference between dinsm and dextm // in that it says: // 2 <= size <= 64 for 'dinsm' but 'dextm' has 32 < size <= 64. // To make the bounds checks similar, the range 1 < size <= 64 is checked // for 'dinsm'. return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 1, 64, 32, 64); case Mips::DINSU: // The ISA spec has a subtle difference between dinsu and dextu in that // the size range of dinsu is specified as 1 <= size <= 32 whereas size // for dextu is 0 < size <= 32. The range checked for dinsu here is // 0 < size <= 32, which is equivalent and similar to dextu. return verifyInsExtInstruction(MI, ErrInfo, 32, 64, 0, 32, 32, 64); case Mips::DEXT: return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 0, 32, 0, 63); case Mips::DEXTM: return verifyInsExtInstruction(MI, ErrInfo, 0, 32, 32, 64, 32, 64); case Mips::DEXTU: return verifyInsExtInstruction(MI, ErrInfo, 32, 64, 0, 32, 32, 64); case Mips::TAILCALLREG: case Mips::PseudoIndirectBranch: case Mips::JR: case Mips::JR64: case Mips::JALR: case Mips::JALR64: case Mips::JALRPseudo: if (!Subtarget.useIndirectJumpsHazard()) return true; ErrInfo = "invalid instruction when using jump guards!"; return false; default: return true; } return true; } std::pair MipsInstrInfo::decomposeMachineOperandsTargetFlags(unsigned TF) const { return std::make_pair(TF, 0u); } ArrayRef> MipsInstrInfo::getSerializableDirectMachineOperandTargetFlags() const { using namespace MipsII; static const std::pair Flags[] = { {MO_GOT, "mips-got"}, {MO_GOT_CALL, "mips-got-call"}, {MO_GPREL, "mips-gprel"}, {MO_ABS_HI, "mips-abs-hi"}, {MO_ABS_LO, "mips-abs-lo"}, {MO_TLSGD, "mips-tlsgd"}, {MO_TLSLDM, "mips-tlsldm"}, {MO_DTPREL_HI, "mips-dtprel-hi"}, {MO_DTPREL_LO, "mips-dtprel-lo"}, {MO_GOTTPREL, "mips-gottprel"}, {MO_TPREL_HI, "mips-tprel-hi"}, {MO_TPREL_LO, "mips-tprel-lo"}, {MO_GPOFF_HI, "mips-gpoff-hi"}, {MO_GPOFF_LO, "mips-gpoff-lo"}, {MO_GOT_DISP, "mips-got-disp"}, {MO_GOT_PAGE, "mips-got-page"}, {MO_GOT_OFST, "mips-got-ofst"}, {MO_HIGHER, "mips-higher"}, {MO_HIGHEST, "mips-highest"}, {MO_GOT_HI16, "mips-got-hi16"}, {MO_GOT_LO16, "mips-got-lo16"}, {MO_CALL_HI16, "mips-call-hi16"}, {MO_CALL_LO16, "mips-call-lo16"} }; return makeArrayRef(Flags); }