| //===-- llvm/CodeGen/AllocationOrder.cpp - Allocation Order ---------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements an allocation order for virtual registers. |
| // |
| // The preferred allocation order for a virtual register depends on allocation |
| // hints and target hooks. The AllocationOrder class encapsulates all of that. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "regalloc" |
| #include "AllocationOrder.h" |
| #include "llvm/CodeGen/MachineFunction.h" |
| #include "llvm/CodeGen/MachineRegisterInfo.h" |
| #include "llvm/CodeGen/RegisterClassInfo.h" |
| #include "llvm/CodeGen/VirtRegMap.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Target/TargetMachine.h" |
| |
| using namespace llvm; |
| |
| // Compare VirtRegMap::getRegAllocPref(). |
| AllocationOrder::AllocationOrder(unsigned VirtReg, |
| const VirtRegMap &VRM, |
| const RegisterClassInfo &RegClassInfo) |
| : Pos(0) { |
| const MachineFunction &MF = VRM.getMachineFunction(); |
| const TargetRegisterInfo *TRI = &VRM.getTargetRegInfo(); |
| Order = RegClassInfo.getOrder(MF.getRegInfo().getRegClass(VirtReg)); |
| TRI->getRegAllocationHints(VirtReg, Order, Hints, MF, &VRM); |
| |
| DEBUG({ |
| if (!Hints.empty()) { |
| dbgs() << "hints:"; |
| for (unsigned I = 0, E = Hints.size(); I != E; ++I) |
| dbgs() << ' ' << PrintReg(Hints[I], TRI); |
| dbgs() << '\n'; |
| } |
| }); |
| } |
| |
| bool AllocationOrder::isHint(unsigned PhysReg) const { |
| return std::find(Hints.begin(), Hints.end(), PhysReg) != Hints.end(); |
| } |
| |
| unsigned AllocationOrder::next() { |
| if (Pos < Hints.size()) |
| return Hints[Pos++]; |
| ArrayRef<MCPhysReg>::iterator I = Order.begin() + (Pos - Hints.size()); |
| ArrayRef<MCPhysReg>::iterator E = Order.end(); |
| while (I != E) { |
| unsigned Reg = *I++; |
| ++Pos; |
| if (!isHint(Reg)) |
| return Reg; |
| } |
| return 0; |
| } |