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Diffstat (limited to 'contrib/llvm/lib/CodeGen/MachineRegisterInfo.cpp')
-rw-r--r-- | contrib/llvm/lib/CodeGen/MachineRegisterInfo.cpp | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/MachineRegisterInfo.cpp b/contrib/llvm/lib/CodeGen/MachineRegisterInfo.cpp new file mode 100644 index 0000000..b3fb337 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/MachineRegisterInfo.cpp @@ -0,0 +1,248 @@ +//===-- lib/Codegen/MachineRegisterInfo.cpp -------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// Implementation of the MachineRegisterInfo class. +// +//===----------------------------------------------------------------------===// + +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/MachineInstrBuilder.h" +#include "llvm/Target/TargetInstrInfo.h" +#include "llvm/Support/CommandLine.h" +using namespace llvm; + +MachineRegisterInfo::MachineRegisterInfo(const TargetRegisterInfo &TRI) { + VRegInfo.reserve(256); + RegAllocHints.reserve(256); + RegClass2VRegMap = new std::vector<unsigned>[TRI.getNumRegClasses()]; + UsedPhysRegs.resize(TRI.getNumRegs()); + + // Create the physreg use/def lists. + PhysRegUseDefLists = new MachineOperand*[TRI.getNumRegs()]; + memset(PhysRegUseDefLists, 0, sizeof(MachineOperand*)*TRI.getNumRegs()); +} + +MachineRegisterInfo::~MachineRegisterInfo() { +#ifndef NDEBUG + for (unsigned i = 0, e = getNumVirtRegs(); i != e; ++i) + assert(VRegInfo[TargetRegisterInfo::index2VirtReg(i)].second == 0 && + "Vreg use list non-empty still?"); + for (unsigned i = 0, e = UsedPhysRegs.size(); i != e; ++i) + assert(!PhysRegUseDefLists[i] && + "PhysRegUseDefLists has entries after all instructions are deleted"); +#endif + delete [] PhysRegUseDefLists; + delete [] RegClass2VRegMap; +} + +/// setRegClass - Set the register class of the specified virtual register. +/// +void +MachineRegisterInfo::setRegClass(unsigned Reg, const TargetRegisterClass *RC) { + const TargetRegisterClass *OldRC = VRegInfo[Reg].first; + VRegInfo[Reg].first = RC; + + // Remove from old register class's vregs list. This may be slow but + // fortunately this operation is rarely needed. + std::vector<unsigned> &VRegs = RegClass2VRegMap[OldRC->getID()]; + std::vector<unsigned>::iterator I = + std::find(VRegs.begin(), VRegs.end(), Reg); + VRegs.erase(I); + + // Add to new register class's vregs list. + RegClass2VRegMap[RC->getID()].push_back(Reg); +} + +const TargetRegisterClass * +MachineRegisterInfo::constrainRegClass(unsigned Reg, + const TargetRegisterClass *RC) { + const TargetRegisterClass *OldRC = getRegClass(Reg); + if (OldRC == RC) + return RC; + const TargetRegisterClass *NewRC = getCommonSubClass(OldRC, RC); + if (!NewRC) + return 0; + if (NewRC != OldRC) + setRegClass(Reg, NewRC); + return NewRC; +} + +/// createVirtualRegister - Create and return a new virtual register in the +/// function with the specified register class. +/// +unsigned +MachineRegisterInfo::createVirtualRegister(const TargetRegisterClass *RegClass){ + assert(RegClass && "Cannot create register without RegClass!"); + + // New virtual register number. + unsigned Reg = TargetRegisterInfo::index2VirtReg(getNumVirtRegs()); + + // Add a reg, but keep track of whether the vector reallocated or not. + const unsigned FirstVirtReg = TargetRegisterInfo::index2VirtReg(0); + void *ArrayBase = getNumVirtRegs() == 0 ? 0 : &VRegInfo[FirstVirtReg]; + VRegInfo.grow(Reg); + VRegInfo[Reg].first = RegClass; + RegAllocHints.grow(Reg); + + if (ArrayBase && &VRegInfo[FirstVirtReg] != ArrayBase) + // The vector reallocated, handle this now. + HandleVRegListReallocation(); + RegClass2VRegMap[RegClass->getID()].push_back(Reg); + return Reg; +} + +/// HandleVRegListReallocation - We just added a virtual register to the +/// VRegInfo info list and it reallocated. Update the use/def lists info +/// pointers. +void MachineRegisterInfo::HandleVRegListReallocation() { + // The back pointers for the vreg lists point into the previous vector. + // Update them to point to their correct slots. + for (unsigned i = 0, e = getNumVirtRegs(); i != e; ++i) { + unsigned Reg = TargetRegisterInfo::index2VirtReg(i); + MachineOperand *List = VRegInfo[Reg].second; + if (!List) continue; + // Update the back-pointer to be accurate once more. + List->Contents.Reg.Prev = &VRegInfo[Reg].second; + } +} + +/// replaceRegWith - Replace all instances of FromReg with ToReg in the +/// machine function. This is like llvm-level X->replaceAllUsesWith(Y), +/// except that it also changes any definitions of the register as well. +void MachineRegisterInfo::replaceRegWith(unsigned FromReg, unsigned ToReg) { + assert(FromReg != ToReg && "Cannot replace a reg with itself"); + + // TODO: This could be more efficient by bulk changing the operands. + for (reg_iterator I = reg_begin(FromReg), E = reg_end(); I != E; ) { + MachineOperand &O = I.getOperand(); + ++I; + O.setReg(ToReg); + } +} + + +/// getVRegDef - Return the machine instr that defines the specified virtual +/// register or null if none is found. This assumes that the code is in SSA +/// form, so there should only be one definition. +MachineInstr *MachineRegisterInfo::getVRegDef(unsigned Reg) const { + // Since we are in SSA form, we can use the first definition. + if (!def_empty(Reg)) + return &*def_begin(Reg); + return 0; +} + +bool MachineRegisterInfo::hasOneUse(unsigned RegNo) const { + use_iterator UI = use_begin(RegNo); + if (UI == use_end()) + return false; + return ++UI == use_end(); +} + +bool MachineRegisterInfo::hasOneNonDBGUse(unsigned RegNo) const { + use_nodbg_iterator UI = use_nodbg_begin(RegNo); + if (UI == use_nodbg_end()) + return false; + return ++UI == use_nodbg_end(); +} + +/// clearKillFlags - Iterate over all the uses of the given register and +/// clear the kill flag from the MachineOperand. This function is used by +/// optimization passes which extend register lifetimes and need only +/// preserve conservative kill flag information. +void MachineRegisterInfo::clearKillFlags(unsigned Reg) const { + for (use_iterator UI = use_begin(Reg), UE = use_end(); UI != UE; ++UI) + UI.getOperand().setIsKill(false); +} + +bool MachineRegisterInfo::isLiveIn(unsigned Reg) const { + for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I) + if (I->first == Reg || I->second == Reg) + return true; + return false; +} + +bool MachineRegisterInfo::isLiveOut(unsigned Reg) const { + for (liveout_iterator I = liveout_begin(), E = liveout_end(); I != E; ++I) + if (*I == Reg) + return true; + return false; +} + +/// getLiveInPhysReg - If VReg is a live-in virtual register, return the +/// corresponding live-in physical register. +unsigned MachineRegisterInfo::getLiveInPhysReg(unsigned VReg) const { + for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I) + if (I->second == VReg) + return I->first; + return 0; +} + +/// getLiveInVirtReg - If PReg is a live-in physical register, return the +/// corresponding live-in physical register. +unsigned MachineRegisterInfo::getLiveInVirtReg(unsigned PReg) const { + for (livein_iterator I = livein_begin(), E = livein_end(); I != E; ++I) + if (I->first == PReg) + return I->second; + return 0; +} + +/// EmitLiveInCopies - Emit copies to initialize livein virtual registers +/// into the given entry block. +void +MachineRegisterInfo::EmitLiveInCopies(MachineBasicBlock *EntryMBB, + const TargetRegisterInfo &TRI, + const TargetInstrInfo &TII) { + // Emit the copies into the top of the block. + for (unsigned i = 0, e = LiveIns.size(); i != e; ++i) + if (LiveIns[i].second) { + if (use_empty(LiveIns[i].second)) { + // The livein has no uses. Drop it. + // + // It would be preferable to have isel avoid creating live-in + // records for unused arguments in the first place, but it's + // complicated by the debug info code for arguments. + LiveIns.erase(LiveIns.begin() + i); + --i; --e; + } else { + DebugLoc DL; + // If there is a location for this live in then use it. + DenseMap<unsigned, DebugLoc>::iterator DLI = + LiveInLocs.find(LiveIns[i].second); + if (DLI != LiveInLocs.end()) + DL = DLI->second; + + // Emit a copy. + BuildMI(*EntryMBB, EntryMBB->begin(), DL, + TII.get(TargetOpcode::COPY), LiveIns[i].second) + .addReg(LiveIns[i].first); + + // Add the register to the entry block live-in set. + EntryMBB->addLiveIn(LiveIns[i].first); + } + } else { + // Add the register to the entry block live-in set. + EntryMBB->addLiveIn(LiveIns[i].first); + } +} + +void MachineRegisterInfo::closePhysRegsUsed(const TargetRegisterInfo &TRI) { + for (int i = UsedPhysRegs.find_first(); i >= 0; + i = UsedPhysRegs.find_next(i)) + for (const unsigned *SS = TRI.getSubRegisters(i); + unsigned SubReg = *SS; ++SS) + if (SubReg > unsigned(i)) + UsedPhysRegs.set(SubReg); +} + +#ifndef NDEBUG +void MachineRegisterInfo::dumpUses(unsigned Reg) const { + for (use_iterator I = use_begin(Reg), E = use_end(); I != E; ++I) + I.getOperand().getParent()->dump(); +} +#endif |