diff options
Diffstat (limited to 'lib/Target/AArch64/AArch64InstrInfo.cpp')
| -rw-r--r-- | lib/Target/AArch64/AArch64InstrInfo.cpp | 805 |
1 files changed, 805 insertions, 0 deletions
diff --git a/lib/Target/AArch64/AArch64InstrInfo.cpp b/lib/Target/AArch64/AArch64InstrInfo.cpp new file mode 100644 index 0000000000..967960c1e5 --- /dev/null +++ b/lib/Target/AArch64/AArch64InstrInfo.cpp @@ -0,0 +1,805 @@ +//===- AArch64InstrInfo.cpp - AArch64 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 AArch64 implementation of the TargetInstrInfo class. +// +//===----------------------------------------------------------------------===// + +#include "AArch64.h" +#include "AArch64InstrInfo.h" +#include "AArch64MachineFunctionInfo.h" +#include "AArch64TargetMachine.h" +#include "MCTargetDesc/AArch64BaseInfo.h" +#include "MCTargetDesc/AArch64MCTargetDesc.h" +#include "llvm/CodeGen/MachineConstantPool.h" +#include "llvm/CodeGen/MachineDominators.h" +#include "llvm/CodeGen/MachineFrameInfo.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/IR/Function.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/TargetRegistry.h" + +#include <algorithm> + +#define GET_INSTRINFO_CTOR +#include "AArch64GenInstrInfo.inc" + +using namespace llvm; + +AArch64InstrInfo::AArch64InstrInfo(const AArch64Subtarget &STI) + : AArch64GenInstrInfo(AArch64::ADJCALLSTACKDOWN, AArch64::ADJCALLSTACKUP), + RI(*this, STI), Subtarget(STI) {} + +void AArch64InstrInfo::copyPhysReg(MachineBasicBlock &MBB, + MachineBasicBlock::iterator I, DebugLoc DL, + unsigned DestReg, unsigned SrcReg, + bool KillSrc) const { + unsigned Opc = 0; + unsigned ZeroReg = 0; + if (DestReg == AArch64::XSP || SrcReg == AArch64::XSP) { + // E.g. ADD xDst, xsp, #0 (, lsl #0) + BuildMI(MBB, I, DL, get(AArch64::ADDxxi_lsl0_s), DestReg) + .addReg(SrcReg) + .addImm(0); + return; + } else if (DestReg == AArch64::WSP || SrcReg == AArch64::WSP) { + // E.g. ADD wDST, wsp, #0 (, lsl #0) + BuildMI(MBB, I, DL, get(AArch64::ADDwwi_lsl0_s), DestReg) + .addReg(SrcReg) + .addImm(0); + return; + } else if (DestReg == AArch64::NZCV) { + assert(AArch64::GPR64RegClass.contains(SrcReg)); + // E.g. MSR NZCV, xDST + BuildMI(MBB, I, DL, get(AArch64::MSRix)) + .addImm(A64SysReg::NZCV) + .addReg(SrcReg); + } else if (SrcReg == AArch64::NZCV) { + assert(AArch64::GPR64RegClass.contains(DestReg)); + // E.g. MRS xDST, NZCV + BuildMI(MBB, I, DL, get(AArch64::MRSxi), DestReg) + .addImm(A64SysReg::NZCV); + } else if (AArch64::GPR64RegClass.contains(DestReg)) { + assert(AArch64::GPR64RegClass.contains(SrcReg)); + Opc = AArch64::ORRxxx_lsl; + ZeroReg = AArch64::XZR; + } else if (AArch64::GPR32RegClass.contains(DestReg)) { + assert(AArch64::GPR32RegClass.contains(SrcReg)); + Opc = AArch64::ORRwww_lsl; + ZeroReg = AArch64::WZR; + } else if (AArch64::FPR32RegClass.contains(DestReg)) { + assert(AArch64::FPR32RegClass.contains(SrcReg)); + BuildMI(MBB, I, DL, get(AArch64::FMOVss), DestReg) + .addReg(SrcReg); + return; + } else if (AArch64::FPR64RegClass.contains(DestReg)) { + assert(AArch64::FPR64RegClass.contains(SrcReg)); + BuildMI(MBB, I, DL, get(AArch64::FMOVdd), DestReg) + .addReg(SrcReg); + return; + } else if (AArch64::FPR128RegClass.contains(DestReg)) { + assert(AArch64::FPR128RegClass.contains(SrcReg)); + + // FIXME: there's no good way to do this, at least without NEON: + // + There's no single move instruction for q-registers + // + We can't create a spill slot and use normal STR/LDR because stack + // allocation has already happened + // + We can't go via X-registers with FMOV because register allocation has + // already happened. + // This may not be efficient, but at least it works. + BuildMI(MBB, I, DL, get(AArch64::LSFP128_PreInd_STR), AArch64::XSP) + .addReg(SrcReg) + .addReg(AArch64::XSP) + .addImm(0x1ff & -16); + + BuildMI(MBB, I, DL, get(AArch64::LSFP128_PostInd_LDR), DestReg) + .addReg(AArch64::XSP, RegState::Define) + .addReg(AArch64::XSP) + .addImm(16); + return; + } else { + llvm_unreachable("Unknown register class in copyPhysReg"); + } + + // E.g. ORR xDst, xzr, xSrc, lsl #0 + BuildMI(MBB, I, DL, get(Opc), DestReg) + .addReg(ZeroReg) + .addReg(SrcReg) + .addImm(0); +} + +MachineInstr * +AArch64InstrInfo::emitFrameIndexDebugValue(MachineFunction &MF, int FrameIx, + uint64_t Offset, const MDNode *MDPtr, + DebugLoc DL) const { + MachineInstrBuilder MIB = BuildMI(MF, DL, get(AArch64::DBG_VALUE)) + .addFrameIndex(FrameIx).addImm(0) + .addImm(Offset) + .addMetadata(MDPtr); + return &*MIB; +} + +/// Does the Opcode represent a conditional branch that we can remove and re-add +/// at the end of a basic block? +static bool isCondBranch(unsigned Opc) { + return Opc == AArch64::Bcc || Opc == AArch64::CBZw || Opc == AArch64::CBZx || + Opc == AArch64::CBNZw || Opc == AArch64::CBNZx || + Opc == AArch64::TBZwii || Opc == AArch64::TBZxii || + Opc == AArch64::TBNZwii || Opc == AArch64::TBNZxii; +} + +/// Takes apart a given conditional branch MachineInstr (see isCondBranch), +/// setting TBB to the destination basic block and populating the Cond vector +/// with data necessary to recreate the conditional branch at a later +/// date. First element will be the opcode, and subsequent ones define the +/// conditions being branched on in an instruction-specific manner. +static void classifyCondBranch(MachineInstr *I, MachineBasicBlock *&TBB, + SmallVectorImpl<MachineOperand> &Cond) { + switch(I->getOpcode()) { + case AArch64::Bcc: + case AArch64::CBZw: + case AArch64::CBZx: + case AArch64::CBNZw: + case AArch64::CBNZx: + // These instructions just have one predicate operand in position 0 (either + // a condition code or a register being compared). + Cond.push_back(MachineOperand::CreateImm(I->getOpcode())); + Cond.push_back(I->getOperand(0)); + TBB = I->getOperand(1).getMBB(); + return; + case AArch64::TBZwii: + case AArch64::TBZxii: + case AArch64::TBNZwii: + case AArch64::TBNZxii: + // These have two predicate operands: a register and a bit position. + Cond.push_back(MachineOperand::CreateImm(I->getOpcode())); + Cond.push_back(I->getOperand(0)); + Cond.push_back(I->getOperand(1)); + TBB = I->getOperand(2).getMBB(); + return; + default: + llvm_unreachable("Unknown conditional branch to classify"); + } +} + + +bool +AArch64InstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB, + MachineBasicBlock *&FBB, + SmallVectorImpl<MachineOperand> &Cond, + bool AllowModify) const { + // If the block has no terminators, it just falls into the block after it. + MachineBasicBlock::iterator I = MBB.end(); + if (I == MBB.begin()) + return false; + --I; + while (I->isDebugValue()) { + if (I == MBB.begin()) + return false; + --I; + } + if (!isUnpredicatedTerminator(I)) + return false; + + // Get the last instruction in the block. + MachineInstr *LastInst = I; + + // If there is only one terminator instruction, process it. + unsigned LastOpc = LastInst->getOpcode(); + if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) { + if (LastOpc == AArch64::Bimm) { + TBB = LastInst->getOperand(0).getMBB(); + return false; + } + if (isCondBranch(LastOpc)) { + classifyCondBranch(LastInst, TBB, Cond); + return false; + } + return true; // Can't handle indirect branch. + } + + // Get the instruction before it if it is a terminator. + MachineInstr *SecondLastInst = I; + unsigned SecondLastOpc = SecondLastInst->getOpcode(); + + // If AllowModify is true and the block ends with two or more unconditional + // branches, delete all but the first unconditional branch. + if (AllowModify && LastOpc == AArch64::Bimm) { + while (SecondLastOpc == AArch64::Bimm) { + LastInst->eraseFromParent(); + LastInst = SecondLastInst; + LastOpc = LastInst->getOpcode(); + if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) { + // Return now the only terminator is an unconditional branch. + TBB = LastInst->getOperand(0).getMBB(); + return false; + } else { + SecondLastInst = I; + SecondLastOpc = SecondLastInst->getOpcode(); + } + } + } + + // If there are three terminators, we don't know what sort of block this is. + if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I)) + return true; + + // If the block ends with a B and a Bcc, handle it. + if (LastOpc == AArch64::Bimm) { + if (SecondLastOpc == AArch64::Bcc) { + TBB = SecondLastInst->getOperand(1).getMBB(); + Cond.push_back(MachineOperand::CreateImm(AArch64::Bcc)); + Cond.push_back(SecondLastInst->getOperand(0)); + FBB = LastInst->getOperand(0).getMBB(); + return false; + } else if (isCondBranch(SecondLastOpc)) { + classifyCondBranch(SecondLastInst, TBB, Cond); + FBB = LastInst->getOperand(0).getMBB(); + return false; + } + } + + // If the block ends with two unconditional branches, handle it. The second + // one is not executed, so remove it. + if (SecondLastOpc == AArch64::Bimm && LastOpc == AArch64::Bimm) { + TBB = SecondLastInst->getOperand(0).getMBB(); + I = LastInst; + if (AllowModify) + I->eraseFromParent(); + return false; + } + + // Otherwise, can't handle this. + return true; +} + +bool AArch64InstrInfo::ReverseBranchCondition( + SmallVectorImpl<MachineOperand> &Cond) const { + switch (Cond[0].getImm()) { + case AArch64::Bcc: { + A64CC::CondCodes CC = static_cast<A64CC::CondCodes>(Cond[1].getImm()); + CC = A64InvertCondCode(CC); + Cond[1].setImm(CC); + return false; + } + case AArch64::CBZw: + Cond[0].setImm(AArch64::CBNZw); + return false; + case AArch64::CBZx: + Cond[0].setImm(AArch64::CBNZx); + return false; + case AArch64::CBNZw: + Cond[0].setImm(AArch64::CBZw); + return false; + case AArch64::CBNZx: + Cond[0].setImm(AArch64::CBZx); + return false; + case AArch64::TBZwii: + Cond[0].setImm(AArch64::TBNZwii); + return false; + case AArch64::TBZxii: + Cond[0].setImm(AArch64::TBNZxii); + return false; + case AArch64::TBNZwii: + Cond[0].setImm(AArch64::TBZwii); + return false; + case AArch64::TBNZxii: + Cond[0].setImm(AArch64::TBZxii); + return false; + default: + llvm_unreachable("Unknown branch type"); + } +} + + +unsigned +AArch64InstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB, + MachineBasicBlock *FBB, + const SmallVectorImpl<MachineOperand> &Cond, + DebugLoc DL) const { + if (FBB == 0 && Cond.empty()) { + BuildMI(&MBB, DL, get(AArch64::Bimm)).addMBB(TBB); + return 1; + } else if (FBB == 0) { + MachineInstrBuilder MIB = BuildMI(&MBB, DL, get(Cond[0].getImm())); + for (int i = 1, e = Cond.size(); i != e; ++i) + MIB.addOperand(Cond[i]); + MIB.addMBB(TBB); + return 1; + } + + MachineInstrBuilder MIB = BuildMI(&MBB, DL, get(Cond[0].getImm())); + for (int i = 1, e = Cond.size(); i != e; ++i) + MIB.addOperand(Cond[i]); + MIB.addMBB(TBB); + + BuildMI(&MBB, DL, get(AArch64::Bimm)).addMBB(FBB); + return 2; +} + +unsigned AArch64InstrInfo::RemoveBranch(MachineBasicBlock &MBB) const { + MachineBasicBlock::iterator I = MBB.end(); + if (I == MBB.begin()) return 0; + --I; + while (I->isDebugValue()) { + if (I == MBB.begin()) + return 0; + --I; + } + if (I->getOpcode() != AArch64::Bimm && !isCondBranch(I->getOpcode())) + return 0; + + // Remove the branch. + I->eraseFromParent(); + + I = MBB.end(); + + if (I == MBB.begin()) return 1; + --I; + if (!isCondBranch(I->getOpcode())) + return 1; + + // Remove the branch. + I->eraseFromParent(); + return 2; +} + +bool +AArch64InstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MBBI) const { + MachineInstr &MI = *MBBI; + MachineBasicBlock &MBB = *MI.getParent(); + + unsigned Opcode = MI.getOpcode(); + switch (Opcode) { + case AArch64::TLSDESC_BLRx: { + MachineInstr *NewMI = + BuildMI(MBB, MBBI, MI.getDebugLoc(), get(AArch64::TLSDESCCALL)) + .addOperand(MI.getOperand(1)); + MI.setDesc(get(AArch64::BLRx)); + + llvm::finalizeBundle(MBB, NewMI, *++MBBI); + return true; + } + default: + return false; + } + + return false; +} + +void +AArch64InstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB, + MachineBasicBlock::iterator MBBI, + unsigned SrcReg, bool isKill, + int FrameIdx, + const TargetRegisterClass *RC, + const TargetRegisterInfo *TRI) const { + DebugLoc DL = MBB.findDebugLoc(MBBI); + MachineFunction &MF = *MBB.getParent(); + MachineFrameInfo &MFI = *MF.getFrameInfo(); + unsigned Align = MFI.getObjectAlignment(FrameIdx); + + MachineMemOperand *MMO + = MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx), + MachineMemOperand::MOStore, + MFI.getObjectSize(FrameIdx), + Align); + + unsigned StoreOp = 0; + if (RC->hasType(MVT::i64) || RC->hasType(MVT::i32)) { + switch(RC->getSize()) { + case 4: StoreOp = AArch64::LS32_STR; break; + case 8: StoreOp = AArch64::LS64_STR; break; + default: + llvm_unreachable("Unknown size for regclass"); + } + } else { + assert((RC->hasType(MVT::f32) || RC->hasType(MVT::f64) || + RC->hasType(MVT::f128)) + && "Expected integer or floating type for store"); + switch (RC->getSize()) { + case 4: StoreOp = AArch64::LSFP32_STR; break; + case 8: StoreOp = AArch64::LSFP64_STR; break; + case 16: StoreOp = AArch64::LSFP128_STR; break; + default: + llvm_unreachable("Unknown size for regclass"); + } + } + + MachineInstrBuilder NewMI = BuildMI(MBB, MBBI, DL, get(StoreOp)); + NewMI.addReg(SrcReg, getKillRegState(isKill)) + .addFrameIndex(FrameIdx) + .addImm(0) + .addMemOperand(MMO); + +} + +void +AArch64InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB, + MachineBasicBlock::iterator MBBI, + unsigned DestReg, int FrameIdx, + const TargetRegisterClass *RC, + const TargetRegisterInfo *TRI) const { + DebugLoc DL = MBB.findDebugLoc(MBBI); + MachineFunction &MF = *MBB.getParent(); + MachineFrameInfo &MFI = *MF.getFrameInfo(); + unsigned Align = MFI.getObjectAlignment(FrameIdx); + + MachineMemOperand *MMO + = MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx), + MachineMemOperand::MOLoad, + MFI.getObjectSize(FrameIdx), + Align); + + unsigned LoadOp = 0; + if (RC->hasType(MVT::i64) || RC->hasType(MVT::i32)) { + switch(RC->getSize()) { + case 4: LoadOp = AArch64::LS32_LDR; break; + case 8: LoadOp = AArch64::LS64_LDR; break; + default: + llvm_unreachable("Unknown size for regclass"); + } + } else { + assert((RC->hasType(MVT::f32) || RC->hasType(MVT::f64) + || RC->hasType(MVT::f128)) + && "Expected integer or floating type for store"); + switch (RC->getSize()) { + case 4: LoadOp = AArch64::LSFP32_LDR; break; + case 8: LoadOp = AArch64::LSFP64_LDR; break; + case 16: LoadOp = AArch64::LSFP128_LDR; break; + default: + llvm_unreachable("Unknown size for regclass"); + } + } + + MachineInstrBuilder NewMI = BuildMI(MBB, MBBI, DL, get(LoadOp), DestReg); + NewMI.addFrameIndex(FrameIdx) + .addImm(0) + .addMemOperand(MMO); +} + +unsigned AArch64InstrInfo::estimateRSStackLimit(MachineFunction &MF) const { + unsigned Limit = (1 << 16) - 1; + for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) { + for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); + I != E; ++I) { + for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) { + if (!I->getOperand(i).isFI()) continue; + + // When using ADDxxi_lsl0_s to get the address of a stack object, 0xfff + // is the largest offset guaranteed to fit in the immediate offset. + if (I->getOpcode() == AArch64::ADDxxi_lsl0_s) { + Limit = std::min(Limit, 0xfffu); + break; + } + + int AccessScale, MinOffset, MaxOffset; + getAddressConstraints(*I, AccessScale, MinOffset, MaxOffset); + Limit = std::min(Limit, static_cast<unsigned>(MaxOffset)); + + break; // At most one FI per instruction + } + } + } + + return Limit; +} +void AArch64InstrInfo::getAddressConstraints(const MachineInstr &MI, + int &AccessScale, int &MinOffset, + int &MaxOffset) const { + switch (MI.getOpcode()) { + default: llvm_unreachable("Unkown load/store kind"); + case TargetOpcode::DBG_VALUE: + AccessScale = 1; + MinOffset = INT_MIN; + MaxOffset = INT_MAX; + return; + case AArch64::LS8_LDR: case AArch64::LS8_STR: + case AArch64::LSFP8_LDR: case AArch64::LSFP8_STR: + case AArch64::LDRSBw: + case AArch64::LDRSBx: + AccessScale = 1; + MinOffset = 0; + MaxOffset = 0xfff; + return; + case AArch64::LS16_LDR: case AArch64::LS16_STR: + case AArch64::LSFP16_LDR: case AArch64::LSFP16_STR: + case AArch64::LDRSHw: + case AArch64::LDRSHx: + AccessScale = 2; + MinOffset = 0; + MaxOffset = 0xfff * AccessScale; + return; + case AArch64::LS32_LDR: case AArch64::LS32_STR: + case AArch64::LSFP32_LDR: case AArch64::LSFP32_STR: + case AArch64::LDRSWx: + case AArch64::LDPSWx: + AccessScale = 4; + MinOffset = 0; + MaxOffset = 0xfff * AccessScale; + return; + case AArch64::LS64_LDR: case AArch64::LS64_STR: + case AArch64::LSFP64_LDR: case AArch64::LSFP64_STR: + case AArch64::PRFM: + AccessScale = 8; + MinOffset = 0; + MaxOffset = 0xfff * AccessScale; + return; + case AArch64::LSFP128_LDR: case AArch64::LSFP128_STR: + AccessScale = 16; + MinOffset = 0; + MaxOffset = 0xfff * AccessScale; + return; + case AArch64::LSPair32_LDR: case AArch64::LSPair32_STR: + case AArch64::LSFPPair32_LDR: case AArch64::LSFPPair32_STR: + AccessScale = 4; + MinOffset = -0x40 * AccessScale; + MaxOffset = 0x3f * AccessScale; + return; + case AArch64::LSPair64_LDR: case AArch64::LSPair64_STR: + case AArch64::LSFPPair64_LDR: case AArch64::LSFPPair64_STR: + AccessScale = 8; + MinOffset = -0x40 * AccessScale; + MaxOffset = 0x3f * AccessScale; + return; + case AArch64::LSFPPair128_LDR: case AArch64::LSFPPair128_STR: + AccessScale = 16; + MinOffset = -0x40 * AccessScale; + MaxOffset = 0x3f * AccessScale; + return; + } +} + +unsigned AArch64InstrInfo::getInstSizeInBytes(const MachineInstr &MI) const { + const MCInstrDesc &MCID = MI.getDesc(); + const MachineBasicBlock &MBB = *MI.getParent(); + const MachineFunction &MF = *MBB.getParent(); + const MCAsmInfo &MAI = *MF.getTarget().getMCAsmInfo(); + + if (MCID.getSize()) + return MCID.getSize(); + + if (MI.getOpcode() == AArch64::INLINEASM) + return getInlineAsmLength(MI.getOperand(0).getSymbolName(), MAI); + + if (MI.isLabel()) + return 0; + + switch (MI.getOpcode()) { + case TargetOpcode::BUNDLE: + return getInstBundleLength(MI); + case TargetOpcode::IMPLICIT_DEF: + case TargetOpcode::KILL: + case TargetOpcode::PROLOG_LABEL: + case TargetOpcode::EH_LABEL: + case TargetOpcode::DBG_VALUE: + return 0; + case AArch64::CONSTPOOL_ENTRY: + return MI.getOperand(2).getImm(); + case AArch64::TLSDESCCALL: + return 0; + default: + llvm_unreachable("Unknown instruction class"); + } +} + +unsigned AArch64InstrInfo::getInstBundleLength(const MachineInstr &MI) const { + unsigned Size = 0; + MachineBasicBlock::const_instr_iterator I = MI; + MachineBasicBlock::const_instr_iterator E = MI.getParent()->instr_end(); + while (++I != E && I->isInsideBundle()) { + assert(!I->isBundle() && "No nested bundle!"); + Size += getInstSizeInBytes(*I); + } + return Size; +} + +bool llvm::rewriteA64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx, + unsigned FrameReg, int &Offset, + const AArch64InstrInfo &TII) { + MachineBasicBlock &MBB = *MI.getParent(); + MachineFunction &MF = *MBB.getParent(); + MachineFrameInfo &MFI = *MF.getFrameInfo(); + + MFI.getObjectOffset(FrameRegIdx); + llvm_unreachable("Unimplemented rewriteFrameIndex"); +} + +void llvm::emitRegUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI, + DebugLoc dl, const TargetInstrInfo &TII, + unsigned DstReg, unsigned SrcReg, unsigned ScratchReg, + int64_t NumBytes, MachineInstr::MIFlag MIFlags) { + if (NumBytes == 0 && DstReg == SrcReg) + return; + else if (abs(NumBytes) & ~0xffffff) { + // Generically, we have to materialize the offset into a temporary register + // and subtract it. There are a couple of ways this could be done, for now + // we'll go for a literal-pool load. + MachineFunction &MF = *MBB.getParent(); + MachineConstantPool *MCP = MF.getConstantPool(); + const Constant *C + = ConstantInt::get(Type::getInt64Ty(MF.getFunction()->getContext()), + abs(NumBytes)); + unsigned CPI = MCP->getConstantPoolIndex(C, 8); + + // LDR xTMP, .LITPOOL + BuildMI(MBB, MBBI, dl, TII.get(AArch64::LDRx_lit), ScratchReg) + .addConstantPoolIndex(CPI) + .setMIFlag(MIFlags); + + // ADD DST, SRC, xTMP (, lsl #0) + unsigned AddOp = NumBytes > 0 ? AArch64::ADDxxx_uxtx : AArch64::SUBxxx_uxtx; + BuildMI(MBB, MBBI, dl, TII.get(AddOp), DstReg) + .addReg(SrcReg, RegState::Kill) + .addReg(ScratchReg, RegState::Kill) + .addImm(0) + .setMIFlag(MIFlags); + return; + } + + // Now we know that the adjustment can be done in at most two add/sub + // (immediate) instructions, which is always more efficient than a + // literal-pool load, or even a hypothetical movz/movk/add sequence + + // Decide whether we're doing addition or subtraction + unsigned LowOp, HighOp; + if (NumBytes >= 0) { + LowOp = AArch64::ADDxxi_lsl0_s; + HighOp = AArch64::ADDxxi_lsl12_s; + } else { + LowOp = AArch64::SUBxxi_lsl0_s; + HighOp = AArch64::SUBxxi_lsl12_s; + NumBytes = abs(NumBytes); + } + + // If we're here, at the very least a move needs to be produced, which just + // happens to be materializable by an ADD. + if ((NumBytes & 0xfff) || NumBytes == 0) { + BuildMI(MBB, MBBI, dl, TII.get(LowOp), DstReg) + .addReg(SrcReg, RegState::Kill) + .addImm(NumBytes & 0xfff) + .setMIFlag(MIFlags); + + // Next update should use the register we've just defined. + SrcReg = DstReg; + } + + if (NumBytes & 0xfff000) { + BuildMI(MBB, MBBI, dl, TII.get(HighOp), DstReg) + .addReg(SrcReg, RegState::Kill) + .addImm(NumBytes >> 12) + .setMIFlag(MIFlags); + } +} + +void llvm::emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI, + DebugLoc dl, const TargetInstrInfo &TII, + unsigned ScratchReg, int64_t NumBytes, + MachineInstr::MIFlag MIFlags) { + emitRegUpdate(MBB, MI, dl, TII, AArch64::XSP, AArch64::XSP, AArch64::X16, + NumBytes, MIFlags); +} + + +namespace { + struct LDTLSCleanup : public MachineFunctionPass { + static char ID; + LDTLSCleanup() : MachineFunctionPass(ID) {} + + virtual bool runOnMachineFunction(MachineFunction &MF) { + AArch64MachineFunctionInfo* MFI = MF.getInfo<AArch64MachineFunctionInfo>(); + if (MFI->getNumLocalDynamicTLSAccesses() < 2) { + // No point folding accesses if there isn't at least two. + return false; + } + + MachineDominatorTree *DT = &getAnalysis<MachineDominatorTree>(); + return VisitNode(DT->getRootNode(), 0); + } + + // Visit the dominator subtree rooted at Node in pre-order. + // If TLSBaseAddrReg is non-null, then use that to replace any + // TLS_base_addr instructions. Otherwise, create the register + // when the first such instruction is seen, and then use it + // as we encounter more instructions. + bool VisitNode(MachineDomTreeNode *Node, unsigned TLSBaseAddrReg) { + MachineBasicBlock *BB = Node->getBlock(); + bool Changed = false; + + // Traverse the current block. + for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; + ++I) { + switch (I->getOpcode()) { + case AArch64::TLSDESC_BLRx: + // Make sure it's a local dynamic access. + if (!I->getOperand(1).isSymbol() || + strcmp(I->getOperand(1).getSymbolName(), "_TLS_MODULE_BASE_")) + break; + + if (TLSBaseAddrReg) + I = ReplaceTLSBaseAddrCall(I, TLSBaseAddrReg); + else + I = SetRegister(I, &TLSBaseAddrReg); + Changed = true; + break; + default: + break; + } + } + + // Visit the children of this block in the dominator tree. + for (MachineDomTreeNode::iterator I = Node->begin(), E = Node->end(); + I != E; ++I) { + Changed |= VisitNode(*I, TLSBaseAddrReg); + } + + return Changed; + } + + // Replace the TLS_base_addr instruction I with a copy from + // TLSBaseAddrReg, returning the new instruction. + MachineInstr *ReplaceTLSBaseAddrCall(MachineInstr *I, + unsigned TLSBaseAddrReg) { + MachineFunction *MF = I->getParent()->getParent(); + const AArch64TargetMachine *TM = + static_cast<const AArch64TargetMachine *>(&MF->getTarget()); + const AArch64InstrInfo *TII = TM->getInstrInfo(); + + // Insert a Copy from TLSBaseAddrReg to x0, which is where the rest of the + // code sequence assumes the address will be. + MachineInstr *Copy = BuildMI(*I->getParent(), I, I->getDebugLoc(), + TII->get(TargetOpcode::COPY), + AArch64::X0) + .addReg(TLSBaseAddrReg); + + // Erase the TLS_base_addr instruction. + I->eraseFromParent(); + + return Copy; + } + + // Create a virtal register in *TLSBaseAddrReg, and populate it by + // inserting a copy instruction after I. Returns the new instruction. + MachineInstr *SetRegister(MachineInstr *I, unsigned *TLSBaseAddrReg) { + MachineFunction *MF = I->getParent()->getParent(); + const AArch64TargetMachine *TM = + static_cast<const AArch64TargetMachine *>(&MF->getTarget()); + const AArch64InstrInfo *TII = TM->getInstrInfo(); + + // Create a virtual register for the TLS base address. + MachineRegisterInfo &RegInfo = MF->getRegInfo(); + *TLSBaseAddrReg = RegInfo.createVirtualRegister(&AArch64::GPR64RegClass); + + // Insert a copy from X0 to TLSBaseAddrReg for later. + MachineInstr *Next = I->getNextNode(); + MachineInstr *Copy = BuildMI(*I->getParent(), Next, I->getDebugLoc(), + TII->get(TargetOpcode::COPY), + *TLSBaseAddrReg) + .addReg(AArch64::X0); + + return Copy; + } + + virtual const char *getPassName() const { + return "Local Dynamic TLS Access Clean-up"; + } + + virtual void getAnalysisUsage(AnalysisUsage &AU) const { + AU.setPreservesCFG(); + AU.addRequired<MachineDominatorTree>(); + MachineFunctionPass::getAnalysisUsage(AU); + } + }; +} + +char LDTLSCleanup::ID = 0; +FunctionPass* +llvm::createAArch64CleanupLocalDynamicTLSPass() { return new LDTLSCleanup(); } |