diff options
Diffstat (limited to 'lib/Target/Mips/MipsLongBranch.cpp')
| -rw-r--r-- | lib/Target/Mips/MipsLongBranch.cpp | 232 |
1 files changed, 127 insertions, 105 deletions
diff --git a/lib/Target/Mips/MipsLongBranch.cpp b/lib/Target/Mips/MipsLongBranch.cpp index f78203f..5d9f0cf 100644 --- a/lib/Target/Mips/MipsLongBranch.cpp +++ b/lib/Target/Mips/MipsLongBranch.cpp @@ -10,6 +10,10 @@ // This pass expands a branch or jump instruction into a long branch if its // offset is too large to fit into its immediate field. // +// FIXME: +// 1. Fix pc-region jump instructions which cross 256MB segment boundaries. +// 2. If program has inline assembly statements whose size cannot be +// determined accurately, load branch target addresses from the GOT. //===----------------------------------------------------------------------===// #define DEBUG_TYPE "mips-long-branch" @@ -48,7 +52,7 @@ namespace { typedef MachineBasicBlock::reverse_iterator ReverseIter; struct MBBInfo { - uint64_t Size; + uint64_t Size, Address; bool HasLongBranch; MachineInstr *Br; @@ -61,7 +65,10 @@ namespace { static char ID; MipsLongBranch(TargetMachine &tm) : MachineFunctionPass(ID), TM(tm), - TII(static_cast<const MipsInstrInfo*>(tm.getInstrInfo())) {} + TII(static_cast<const MipsInstrInfo*>(tm.getInstrInfo())), + IsPIC(TM.getRelocationModel() == Reloc::PIC_), + ABI(TM.getSubtarget<MipsSubtarget>().getTargetABI()), + LongBranchSeqSize(!IsPIC ? 2 : (ABI == MipsSubtarget::N64 ? 13 : 9)) {} virtual const char *getPassName() const { return "Mips Long Branch"; @@ -81,6 +88,9 @@ namespace { const MipsInstrInfo *TII; MachineFunction *MF; SmallVector<MBBInfo, 16> MBBInfos; + bool IsPIC; + unsigned ABI; + unsigned LongBranchSeqSize; }; char MipsLongBranch::ID = 0; @@ -230,12 +240,6 @@ void MipsLongBranch::replaceBranch(MachineBasicBlock &MBB, Iter Br, // Expand branch instructions to long branches. void MipsLongBranch::expandToLongBranch(MBBInfo &I) { - I.HasLongBranch = true; - - bool IsPIC = TM.getRelocationModel() == Reloc::PIC_; - unsigned ABI = TM.getSubtarget<MipsSubtarget>().getTargetABI(); - bool N64 = ABI == MipsSubtarget::N64; - MachineBasicBlock::iterator Pos; MachineBasicBlock *MBB = I.Br->getParent(), *TgtMBB = getTargetMBB(*I.Br); DebugLoc DL = I.Br->getDebugLoc(); @@ -248,101 +252,105 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) { MBB->addSuccessor(LongBrMBB); if (IsPIC) { - // $longbr: - // addiu $sp, $sp, -regsize * 2 - // sw $ra, 0($sp) - // bal $baltgt - // sw $a3, regsize($sp) - // $baltgt: - // lui $a3, %hi($baltgt) - // lui $at, %hi($tgt) - // addiu $a3, $a3, %lo($baltgt) - // addiu $at, $at, %lo($tgt) - // subu $at, $at, $a3 - // addu $at, $ra, $at - // - // if n64: - // lui $a3, %highest($baltgt) - // lui $ra, %highest($tgt) - // addiu $a3, $a3, %higher($baltgt) - // addiu $ra, $ra, %higher($tgt) - // dsll $a3, $a3, 32 - // dsll $ra, $ra, 32 - // subu $at, $at, $a3 - // addu $at, $at, $ra - // - // lw $ra, 0($sp) - // lw $a3, regsize($sp) - // jr $at - // addiu $sp, $sp, regsize * 2 - // $fallthrough: - // - MF->getInfo<MipsFunctionInfo>()->setEmitNOAT(); MachineBasicBlock *BalTgtMBB = MF->CreateMachineBasicBlock(BB); MF->insert(FallThroughMBB, BalTgtMBB); LongBrMBB->addSuccessor(BalTgtMBB); BalTgtMBB->addSuccessor(TgtMBB); - int RegSize = N64 ? 8 : 4; - unsigned AT = N64 ? Mips::AT_64 : Mips::AT; - unsigned A3 = N64 ? Mips::A3_64 : Mips::A3; - unsigned SP = N64 ? Mips::SP_64 : Mips::SP; - unsigned RA = N64 ? Mips::RA_64 : Mips::RA; - unsigned Load = N64 ? Mips::LD_P8 : Mips::LW; - unsigned Store = N64 ? Mips::SD_P8 : Mips::SW; - unsigned LUi = N64 ? Mips::LUi64 : Mips::LUi; - unsigned ADDiu = N64 ? Mips::DADDiu : Mips::ADDiu; - unsigned ADDu = N64 ? Mips::DADDu : Mips::ADDu; - unsigned SUBu = N64 ? Mips::SUBu : Mips::SUBu; - unsigned JR = N64 ? Mips::JR64 : Mips::JR; - - Pos = LongBrMBB->begin(); - - BuildMI(*LongBrMBB, Pos, DL, TII->get(ADDiu), SP).addReg(SP) - .addImm(-RegSize * 2); - BuildMI(*LongBrMBB, Pos, DL, TII->get(Store)).addReg(RA).addReg(SP) - .addImm(0); - BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::BAL_BR)).addMBB(BalTgtMBB); - BuildMI(*LongBrMBB, Pos, DL, TII->get(Store)).addReg(A3).addReg(SP) - .addImm(RegSize)->setIsInsideBundle(); - - Pos = BalTgtMBB->begin(); - - BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), A3) - .addMBB(BalTgtMBB, MipsII::MO_ABS_HI); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), AT) - .addMBB(TgtMBB, MipsII::MO_ABS_HI); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), A3).addReg(A3) - .addMBB(BalTgtMBB, MipsII::MO_ABS_LO); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), AT).addReg(AT) - .addMBB(TgtMBB, MipsII::MO_ABS_LO); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(SUBu), AT).addReg(AT).addReg(A3); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDu), AT).addReg(RA).addReg(AT); - - if (N64) { - BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), A3) - .addMBB(BalTgtMBB, MipsII::MO_HIGHEST); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(LUi), RA) - .addMBB(TgtMBB, MipsII::MO_HIGHEST); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), A3).addReg(A3) - .addMBB(BalTgtMBB, MipsII::MO_HIGHER); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), RA).addReg(RA) - .addMBB(TgtMBB, MipsII::MO_HIGHER); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DSLL), A3).addReg(A3) - .addImm(32); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DSLL), RA).addReg(RA) - .addImm(32); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(SUBu), AT).addReg(AT).addReg(A3); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDu), AT).addReg(AT).addReg(RA); - I.Size += 4 * 8; + int64_t TgtAddress = MBBInfos[TgtMBB->getNumber()].Address; + int64_t Offset = TgtAddress - (I.Address + I.Size - 20); + int64_t Lo = SignExtend64<16>(Offset & 0xffff); + int64_t Hi = SignExtend64<16>(((Offset + 0x8000) >> 16) & 0xffff); + + if (ABI != MipsSubtarget::N64) { + // $longbr: + // addiu $sp, $sp, -8 + // sw $ra, 0($sp) + // bal $baltgt + // lui $at, %hi($tgt - $baltgt) + // $baltgt: + // addiu $at, $at, %lo($tgt - $baltgt) + // addu $at, $ra, $at + // lw $ra, 0($sp) + // jr $at + // addiu $sp, $sp, 8 + // $fallthrough: + // + + Pos = LongBrMBB->begin(); + + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::ADDiu), Mips::SP) + .addReg(Mips::SP).addImm(-8); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::SW)).addReg(Mips::RA) + .addReg(Mips::SP).addImm(0); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::BAL_BR)).addMBB(BalTgtMBB); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::LUi), Mips::AT).addImm(Hi) + ->setIsInsideBundle(); + + Pos = BalTgtMBB->begin(); + + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::ADDiu), Mips::AT) + .addReg(Mips::AT).addImm(Lo); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::ADDu), Mips::AT) + .addReg(Mips::RA).addReg(Mips::AT); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::LW), Mips::RA) + .addReg(Mips::SP).addImm(0); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::JR)).addReg(Mips::AT); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::ADDiu), Mips::SP) + .addReg(Mips::SP).addImm(8)->setIsInsideBundle(); + } else { + // $longbr: + // daddiu $sp, $sp, -16 + // sd $ra, 0($sp) + // lui64 $at, %highest($tgt - $baltgt) + // daddiu $at, $at, %higher($tgt - $baltgt) + // dsll $at, $at, 16 + // daddiu $at, $at, %hi($tgt - $baltgt) + // bal $baltgt + // dsll $at, $at, 16 + // $baltgt: + // daddiu $at, $at, %lo($tgt - $baltgt) + // daddu $at, $ra, $at + // ld $ra, 0($sp) + // jr64 $at + // daddiu $sp, $sp, 16 + // $fallthrough: + // + + int64_t Higher = SignExtend64<16>(((Offset + 0x80008000) >> 32) & 0xffff); + int64_t Highest = + SignExtend64<16>(((Offset + 0x800080008000LL) >> 48) & 0xffff); + + Pos = LongBrMBB->begin(); + + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::DADDiu), Mips::SP_64) + .addReg(Mips::SP_64).addImm(-16); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::SD)).addReg(Mips::RA_64) + .addReg(Mips::SP_64).addImm(0); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::LUi64), Mips::AT_64) + .addImm(Highest); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::DADDiu), Mips::AT_64) + .addReg(Mips::AT_64).addImm(Higher); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::DSLL), Mips::AT_64) + .addReg(Mips::AT_64).addImm(16); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::DADDiu), Mips::AT_64) + .addReg(Mips::AT_64).addImm(Hi); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::BAL_BR)).addMBB(BalTgtMBB); + BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::DSLL), Mips::AT_64) + .addReg(Mips::AT_64).addImm(16)->setIsInsideBundle(); + + Pos = BalTgtMBB->begin(); + + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DADDiu), Mips::AT_64) + .addReg(Mips::AT_64).addImm(Lo); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DADDu), Mips::AT_64) + .addReg(Mips::RA_64).addReg(Mips::AT_64); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::LD), Mips::RA_64) + .addReg(Mips::SP_64).addImm(0); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::JR64)).addReg(Mips::AT_64); + BuildMI(*BalTgtMBB, Pos, DL, TII->get(Mips::DADDiu), Mips::SP_64) + .addReg(Mips::SP_64).addImm(16)->setIsInsideBundle(); } - - BuildMI(*BalTgtMBB, Pos, DL, TII->get(Load), RA).addReg(SP).addImm(0); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(Load), A3).addReg(SP).addImm(RegSize); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(JR)).addReg(AT); - BuildMI(*BalTgtMBB, Pos, DL, TII->get(ADDiu), SP).addReg(SP) - .addImm(RegSize * 2)->setIsInsideBundle(); - I.Size += 4 * 14; } else { // $longbr: // j $tgt @@ -353,7 +361,6 @@ void MipsLongBranch::expandToLongBranch(MBBInfo &I) { LongBrMBB->addSuccessor(TgtMBB); BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::J)).addMBB(TgtMBB); BuildMI(*LongBrMBB, Pos, DL, TII->get(Mips::NOP))->setIsInsideBundle(); - I.Size += 4 * 2; } if (I.Br->isUnconditionalBranch()) { @@ -401,19 +408,34 @@ bool MipsLongBranch::runOnMachineFunction(MachineFunction &F) { if (!I->Br || I->HasLongBranch) continue; - if (!ForceLongBranch) - // Check if offset fits into 16-bit immediate field of branches. - if (isInt<16>(computeOffset(I->Br) / 4)) - continue; + // Check if offset fits into 16-bit immediate field of branches. + if (!ForceLongBranch && isInt<16>(computeOffset(I->Br) / 4)) + continue; - expandToLongBranch(*I); + I->HasLongBranch = true; + I->Size += LongBranchSeqSize * 4; ++LongBranches; EverMadeChange = MadeChange = true; } } - if (EverMadeChange) - MF->RenumberBlocks(); + if (!EverMadeChange) + return true; + + // Compute basic block addresses. + if (TM.getRelocationModel() == Reloc::PIC_) { + uint64_t Address = 0; + + for (I = MBBInfos.begin(); I != E; Address += I->Size, ++I) + I->Address = Address; + } + + // Do the expansion. + for (I = MBBInfos.begin(); I != E; ++I) + if (I->HasLongBranch) + expandToLongBranch(*I); + + MF->RenumberBlocks(); return true; } |
