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//===-- llvm/CodeGen/VirtRegMap.h - Virtual Register Map -*- C++ -*--------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a virtual register map. This maps virtual registers to
// physical registers and virtual registers to stack slots. It is created and
// updated by a register allocator and then used by a machine code rewriter that
// adds spill code and rewrites virtual into physical register references.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_VIRTREGMAP_H
#define LLVM_CODEGEN_VIRTREGMAP_H
#include "llvm/Target/MRegisterInfo.h"
#include "llvm/ADT/DenseMap.h"
#include <map>
namespace llvm {
class MachineInstr;
class VirtRegMap {
public:
typedef std::multimap<MachineInstr*, unsigned> MI2VirtMapTy;
private:
MachineFunction &MF;
/// Virt2PhysMap - This is a virtual to physical register
/// mapping. Each virtual register is required to have an entry in
/// it; even spilled virtual registers (the register mapped to a
/// spilled register is the temporary used to load it from the
/// stack).
DenseMap<unsigned, VirtReg2IndexFunctor> Virt2PhysMap;
/// Virt2StackSlotMap - This is virtual register to stack slot
/// mapping. Each spilled virtual register has an entry in it
/// which corresponds to the stack slot this register is spilled
/// at.
DenseMap<int, VirtReg2IndexFunctor> Virt2StackSlotMap;
/// MI2VirtMap - This is MachineInstr to virtual register
/// mapping. In the case of memory spill code being folded into
/// instructions, we need to know which virtual register was
/// read/written by this instruction.
MI2VirtMapTy MI2VirtMap;
VirtRegMap(const VirtRegMap&); // DO NOT IMPLEMENT
void operator=(const VirtRegMap&); // DO NOT IMPLEMENT
enum {
NO_PHYS_REG = 0,
NO_STACK_SLOT = ~0 >> 1
};
public:
VirtRegMap(MachineFunction &mf)
: MF(mf), Virt2PhysMap(NO_PHYS_REG), Virt2StackSlotMap(NO_STACK_SLOT) {
grow();
}
void grow();
/// @brief returns true if the specified virtual register is
/// mapped to a physical register
bool hasPhys(unsigned virtReg) const {
return getPhys(virtReg) != NO_PHYS_REG;
}
/// @brief returns the physical register mapped to the specified
/// virtual register
unsigned getPhys(unsigned virtReg) const {
assert(MRegisterInfo::isVirtualRegister(virtReg));
return Virt2PhysMap[virtReg];
}
/// @brief creates a mapping for the specified virtual register to
/// the specified physical register
void assignVirt2Phys(unsigned virtReg, unsigned physReg) {
assert(MRegisterInfo::isVirtualRegister(virtReg) &&
MRegisterInfo::isPhysicalRegister(physReg));
assert(Virt2PhysMap[virtReg] == NO_PHYS_REG &&
"attempt to assign physical register to already mapped "
"virtual register");
Virt2PhysMap[virtReg] = physReg;
}
/// @brief clears the specified virtual register's, physical
/// register mapping
void clearVirt(unsigned virtReg) {
assert(MRegisterInfo::isVirtualRegister(virtReg));
assert(Virt2PhysMap[virtReg] != NO_PHYS_REG &&
"attempt to clear a not assigned virtual register");
Virt2PhysMap[virtReg] = NO_PHYS_REG;
}
/// @brief clears all virtual to physical register mappings
void clearAllVirt() {
Virt2PhysMap.clear();
grow();
}
/// @brief returns true is the specified virtual register is
/// mapped to a stack slot
bool hasStackSlot(unsigned virtReg) const {
return getStackSlot(virtReg) != NO_STACK_SLOT;
}
/// @brief returns the stack slot mapped to the specified virtual
/// register
int getStackSlot(unsigned virtReg) const {
assert(MRegisterInfo::isVirtualRegister(virtReg));
return Virt2StackSlotMap[virtReg];
}
/// @brief create a mapping for the specifed virtual register to
/// the next available stack slot
int assignVirt2StackSlot(unsigned virtReg);
/// @brief create a mapping for the specified virtual register to
/// the specified stack slot
void assignVirt2StackSlot(unsigned virtReg, int frameIndex);
/// @brief updates information about the specified virtual
/// register's value folded into newMI machine instruction
void virtFolded(unsigned virtReg, MachineInstr* oldMI,
MachineInstr* newMI);
/// @brief returns the virtual registers' values folded in memory
/// operands of this instruction
std::pair<MI2VirtMapTy::const_iterator, MI2VirtMapTy::const_iterator>
getFoldedVirts(MachineInstr* MI) const {
return MI2VirtMap.equal_range(MI);
}
void print(std::ostream &OS) const;
void dump() const;
};
inline std::ostream &operator<<(std::ostream &OS, const VirtRegMap &VRM) {
VRM.print(OS);
return OS;
}
/// Spiller interface: Implementations of this interface assign spilled
/// virtual registers to stack slots, rewriting the code.
struct Spiller {
virtual ~Spiller();
virtual bool runOnMachineFunction(MachineFunction &MF,
const VirtRegMap &VRM) = 0;
};
/// createSpiller - Create an return a spiller object, as specified on the
/// command line.
Spiller* createSpiller();
} // End llvm namespace
#endif
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