llvm-6502/include/llvm/MC/MachineLocation.h
Adrian Prantl 13131e62fc Cleanup and document MachineLocation.
Clarify documentation and API to make the difference between register and
register-indirect addressed locations more explicit. Put in a comment
to point out that with the current implementation we cannot specify
a register-indirect location with offset 0 (a breg 0 in DWARF).
No functionality change intended.

rdar://problem/13658587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180641 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-26 21:57:17 +00:00

104 lines
3.5 KiB
C++

//===-- llvm/MC/MachineLocation.h -------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// The MachineLocation class is used to represent a simple location in a machine
// frame. Locations will be one of two forms; a register or an address formed
// from a base address plus an offset. Register indirection can be specified by
// explicitly passing an offset to the constructor.
//
// The MachineMove class is used to represent abstract move operations in the
// prolog/epilog of a compiled function. A collection of these objects can be
// used by a debug consumer to track the location of values when unwinding stack
// frames.
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MACHINELOCATION_H
#define LLVM_MC_MACHINELOCATION_H
namespace llvm {
class MCSymbol;
class MachineLocation {
private:
bool IsRegister; // True if location is a register.
unsigned Register; // gcc/gdb register number.
int Offset; // Displacement if not register.
public:
enum {
// The target register number for an abstract frame pointer. The value is
// an arbitrary value that doesn't collide with any real target register.
VirtualFP = ~0U
};
MachineLocation()
: IsRegister(false), Register(0), Offset(0) {}
/// Create a direct register location.
explicit MachineLocation(unsigned R)
: IsRegister(true), Register(R), Offset(0) {}
/// Create a register-indirect location with an offset.
MachineLocation(unsigned R, int O)
: IsRegister(false), Register(R), Offset(O) {}
bool operator==(const MachineLocation &Other) const {
return IsRegister == Other.IsRegister && Register == Other.Register &&
Offset == Other.Offset;
}
// Accessors
bool isIndirect() const { return !IsRegister; }
bool isReg() const { return IsRegister; }
unsigned getReg() const { return Register; }
int getOffset() const { return Offset; }
void setIsRegister(bool Is) { IsRegister = Is; }
void setRegister(unsigned R) { Register = R; }
void setOffset(int O) { Offset = O; }
/// Make this location a direct register location.
void set(unsigned R) {
IsRegister = true;
Register = R;
Offset = 0;
}
/// Make this location a register-indirect+offset location.
void set(unsigned R, int O) {
IsRegister = false;
Register = R;
Offset = O;
}
#ifndef NDEBUG
void dump();
#endif
};
/// MachineMove - This class represents the save or restore of a callee saved
/// register that exception or debug info needs to know about.
class MachineMove {
private:
/// Label - Symbol for post-instruction address when result of move takes
/// effect.
MCSymbol *Label;
// Move to & from location.
MachineLocation Destination, Source;
public:
MachineMove() : Label(0) {}
MachineMove(MCSymbol *label, const MachineLocation &D,
const MachineLocation &S)
: Label(label), Destination(D), Source(S) {}
// Accessors
MCSymbol *getLabel() const { return Label; }
const MachineLocation &getDestination() const { return Destination; }
const MachineLocation &getSource() const { return Source; }
};
} // End llvm namespace
#endif