| //===-- llvm/CodeGen/AllocationOrder.h - Allocation Order -*- C++ -*-------===// |
| // |
| // 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. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_CODEGEN_ALLOCATIONORDER_H |
| #define LLVM_CODEGEN_ALLOCATIONORDER_H |
| |
| #include "llvm/ADT/ArrayRef.h" |
| #include "llvm/MC/MCRegisterInfo.h" |
| |
| namespace llvm { |
| |
| class RegisterClassInfo; |
| class VirtRegMap; |
| |
| class AllocationOrder { |
| SmallVector<MCPhysReg, 16> Hints; |
| ArrayRef<MCPhysReg> Order; |
| unsigned Pos; |
| |
| public: |
| /// Create a new AllocationOrder for VirtReg. |
| /// @param VirtReg Virtual register to allocate for. |
| /// @param VRM Virtual register map for function. |
| /// @param RegClassInfo Information about reserved and allocatable registers. |
| AllocationOrder(unsigned VirtReg, |
| const VirtRegMap &VRM, |
| const RegisterClassInfo &RegClassInfo); |
| |
| /// Return the next physical register in the allocation order, or 0. |
| /// It is safe to call next() again after it returned 0, it will keep |
| /// returning 0 until rewind() is called. |
| unsigned next(); |
| |
| /// Start over from the beginning. |
| void rewind() { Pos = 0; } |
| |
| /// Return true if the last register returned from next() was a preferred register. |
| bool isHint() const { return Pos <= Hints.size(); } |
| |
| /// Return true if PhysReg is a preferred register. |
| bool isHint(unsigned PhysReg) const; |
| }; |
| |
| } // end namespace llvm |
| |
| #endif |