forked from OSchip/llvm-project
73 lines
2.1 KiB
C++
73 lines
2.1 KiB
C++
//===-- 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
|
|
|
|
namespace llvm {
|
|
|
|
class RegisterClassInfo;
|
|
class VirtRegMap;
|
|
|
|
class AllocationOrder {
|
|
const unsigned *Begin;
|
|
const unsigned *End;
|
|
const unsigned *Pos;
|
|
const RegisterClassInfo &RCI;
|
|
unsigned Hint;
|
|
bool OwnedBegin;
|
|
public:
|
|
|
|
/// AllocationOrder - 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);
|
|
|
|
~AllocationOrder();
|
|
|
|
/// next - 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() {
|
|
// First take the hint.
|
|
if (!Pos) {
|
|
Pos = Begin;
|
|
if (Hint)
|
|
return Hint;
|
|
}
|
|
// Then look at the order from TRI.
|
|
while (Pos != End) {
|
|
unsigned Reg = *Pos++;
|
|
if (Reg != Hint)
|
|
return Reg;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/// rewind - Start over from the beginning.
|
|
void rewind() { Pos = 0; }
|
|
|
|
/// isHint - Return true if PhysReg is a preferred register.
|
|
bool isHint(unsigned PhysReg) const { return PhysReg == Hint; }
|
|
};
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif
|