diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/RegAllocBase.cpp')
-rw-r--r-- | contrib/llvm/lib/CodeGen/RegAllocBase.cpp | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/contrib/llvm/lib/CodeGen/RegAllocBase.cpp b/contrib/llvm/lib/CodeGen/RegAllocBase.cpp new file mode 100644 index 0000000..c035590 --- /dev/null +++ b/contrib/llvm/lib/CodeGen/RegAllocBase.cpp @@ -0,0 +1,145 @@ +//===-- RegAllocBase.cpp - Register Allocator Base Class ------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file defines the RegAllocBase class which provides comon functionality +// for LiveIntervalUnion-based register allocators. +// +//===----------------------------------------------------------------------===// + +#define DEBUG_TYPE "regalloc" +#include "RegAllocBase.h" +#include "Spiller.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/CodeGen/LiveIntervalAnalysis.h" +#include "llvm/CodeGen/LiveRangeEdit.h" +#include "llvm/CodeGen/LiveRegMatrix.h" +#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/CodeGen/MachineRegisterInfo.h" +#include "llvm/CodeGen/VirtRegMap.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" +#ifndef NDEBUG +#include "llvm/ADT/SparseBitVector.h" +#endif +#include "llvm/Support/CommandLine.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/raw_ostream.h" +#include "llvm/Support/Timer.h" + +using namespace llvm; + +STATISTIC(NumNewQueued , "Number of new live ranges queued"); + +// Temporary verification option until we can put verification inside +// MachineVerifier. +static cl::opt<bool, true> +VerifyRegAlloc("verify-regalloc", cl::location(RegAllocBase::VerifyEnabled), + cl::desc("Verify during register allocation")); + +const char *RegAllocBase::TimerGroupName = "Register Allocation"; +bool RegAllocBase::VerifyEnabled = false; + +//===----------------------------------------------------------------------===// +// RegAllocBase Implementation +//===----------------------------------------------------------------------===// + +void RegAllocBase::init(VirtRegMap &vrm, + LiveIntervals &lis, + LiveRegMatrix &mat) { + TRI = &vrm.getTargetRegInfo(); + MRI = &vrm.getRegInfo(); + VRM = &vrm; + LIS = &lis; + Matrix = &mat; + MRI->freezeReservedRegs(vrm.getMachineFunction()); + RegClassInfo.runOnMachineFunction(vrm.getMachineFunction()); +} + +// Visit all the live registers. If they are already assigned to a physical +// register, unify them with the corresponding LiveIntervalUnion, otherwise push +// them on the priority queue for later assignment. +void RegAllocBase::seedLiveRegs() { + NamedRegionTimer T("Seed Live Regs", TimerGroupName, TimePassesIsEnabled); + for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) { + unsigned Reg = TargetRegisterInfo::index2VirtReg(i); + if (MRI->reg_nodbg_empty(Reg)) + continue; + enqueue(&LIS->getInterval(Reg)); + } +} + +// Top-level driver to manage the queue of unassigned VirtRegs and call the +// selectOrSplit implementation. +void RegAllocBase::allocatePhysRegs() { + seedLiveRegs(); + + // Continue assigning vregs one at a time to available physical registers. + while (LiveInterval *VirtReg = dequeue()) { + assert(!VRM->hasPhys(VirtReg->reg) && "Register already assigned"); + + // Unused registers can appear when the spiller coalesces snippets. + if (MRI->reg_nodbg_empty(VirtReg->reg)) { + DEBUG(dbgs() << "Dropping unused " << *VirtReg << '\n'); + LIS->removeInterval(VirtReg->reg); + continue; + } + + // Invalidate all interference queries, live ranges could have changed. + Matrix->invalidateVirtRegs(); + + // selectOrSplit requests the allocator to return an available physical + // register if possible and populate a list of new live intervals that + // result from splitting. + DEBUG(dbgs() << "\nselectOrSplit " + << MRI->getRegClass(VirtReg->reg)->getName() + << ':' << PrintReg(VirtReg->reg) << ' ' << *VirtReg << '\n'); + typedef SmallVector<LiveInterval*, 4> VirtRegVec; + VirtRegVec SplitVRegs; + unsigned AvailablePhysReg = selectOrSplit(*VirtReg, SplitVRegs); + + if (AvailablePhysReg == ~0u) { + // selectOrSplit failed to find a register! + const char *Msg = "ran out of registers during register allocation"; + // Probably caused by an inline asm. + MachineInstr *MI; + for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(VirtReg->reg); + (MI = I.skipInstruction());) + if (MI->isInlineAsm()) + break; + if (MI) + MI->emitError(Msg); + else + report_fatal_error(Msg); + // Keep going after reporting the error. + VRM->assignVirt2Phys(VirtReg->reg, + RegClassInfo.getOrder(MRI->getRegClass(VirtReg->reg)).front()); + continue; + } + + if (AvailablePhysReg) + Matrix->assign(*VirtReg, AvailablePhysReg); + + for (VirtRegVec::iterator I = SplitVRegs.begin(), E = SplitVRegs.end(); + I != E; ++I) { + LiveInterval *SplitVirtReg = *I; + assert(!VRM->hasPhys(SplitVirtReg->reg) && "Register already assigned"); + if (MRI->reg_nodbg_empty(SplitVirtReg->reg)) { + DEBUG(dbgs() << "not queueing unused " << *SplitVirtReg << '\n'); + LIS->removeInterval(SplitVirtReg->reg); + continue; + } + DEBUG(dbgs() << "queuing new interval: " << *SplitVirtReg << "\n"); + assert(TargetRegisterInfo::isVirtualRegister(SplitVirtReg->reg) && + "expect split value in virtual register"); + enqueue(SplitVirtReg); + ++NumNewQueued; + } + } +} |