llvm-6502/include/llvm/CodeGen/LivePhysRegs.h
David Blaikie 7610ba7d24 Fix uses of reserved identifiers starting with an underscore followed by an uppercase letter
This covers essentially all of llvm's headers and libs. One or two weird
cases I wasn't sure were worth/appropriate to fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232394 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-16 18:06:57 +00:00

147 lines
5.3 KiB
C++

//===- llvm/CodeGen/LivePhysRegs.h - Live Physical Register Set -*- 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 the LivePhysRegs utility for tracking liveness of
// physical registers. This can be used for ad-hoc liveness tracking after
// register allocation. You can start with the live-ins/live-outs at the
// beginning/end of a block and update the information while walking the
// instructions inside the block. This implementation tracks the liveness on a
// sub-register granularity.
//
// We assume that the high bits of a physical super-register are not preserved
// unless the instruction has an implicit-use operand reading the super-
// register.
//
// X86 Example:
// %YMM0<def> = ...
// %XMM0<def> = ... (Kills %XMM0, all %XMM0s sub-registers, and %YMM0)
//
// %YMM0<def> = ...
// %XMM0<def> = ..., %YMM0<imp-use> (%YMM0 and all its sub-registers are alive)
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_LIVEPHYSREGS_H
#define LLVM_CODEGEN_LIVEPHYSREGS_H
#include "llvm/ADT/SparseSet.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include <cassert>
namespace llvm {
class MachineInstr;
/// \brief A set of live physical registers with functions to track liveness
/// when walking backward/forward through a basic block.
class LivePhysRegs {
const TargetRegisterInfo *TRI;
SparseSet<unsigned> LiveRegs;
LivePhysRegs(const LivePhysRegs&) = delete;
LivePhysRegs &operator=(const LivePhysRegs&) = delete;
public:
/// \brief Constructs a new empty LivePhysRegs set.
LivePhysRegs() : TRI(nullptr), LiveRegs() {}
/// \brief Constructs and initialize an empty LivePhysRegs set.
LivePhysRegs(const TargetRegisterInfo *TRI) : TRI(TRI) {
assert(TRI && "Invalid TargetRegisterInfo pointer.");
LiveRegs.setUniverse(TRI->getNumRegs());
}
/// \brief Clear and initialize the LivePhysRegs set.
void init(const TargetRegisterInfo *TRI) {
assert(TRI && "Invalid TargetRegisterInfo pointer.");
this->TRI = TRI;
LiveRegs.clear();
LiveRegs.setUniverse(TRI->getNumRegs());
}
/// \brief Clears the LivePhysRegs set.
void clear() { LiveRegs.clear(); }
/// \brief Returns true if the set is empty.
bool empty() const { return LiveRegs.empty(); }
/// \brief Adds a physical register and all its sub-registers to the set.
void addReg(unsigned Reg) {
assert(TRI && "LivePhysRegs is not initialized.");
assert(Reg <= TRI->getNumRegs() && "Expected a physical register.");
for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
SubRegs.isValid(); ++SubRegs)
LiveRegs.insert(*SubRegs);
}
/// \brief Removes a physical register, all its sub-registers, and all its
/// super-registers from the set.
void removeReg(unsigned Reg) {
assert(TRI && "LivePhysRegs is not initialized.");
assert(Reg <= TRI->getNumRegs() && "Expected a physical register.");
for (MCSubRegIterator SubRegs(Reg, TRI, /*IncludeSelf=*/true);
SubRegs.isValid(); ++SubRegs)
LiveRegs.erase(*SubRegs);
for (MCSuperRegIterator SuperRegs(Reg, TRI, /*IncludeSelf=*/false);
SuperRegs.isValid(); ++SuperRegs)
LiveRegs.erase(*SuperRegs);
}
/// \brief Removes physical registers clobbered by the regmask operand @p MO.
void removeRegsInMask(const MachineOperand &MO);
/// \brief Returns true if register @p Reg is contained in the set. This also
/// works if only the super register of @p Reg has been defined, because we
/// always add also all sub-registers to the set.
bool contains(unsigned Reg) const { return LiveRegs.count(Reg); }
/// \brief Simulates liveness when stepping backwards over an
/// instruction(bundle): Remove Defs, add uses. This is the recommended way of
/// calculating liveness.
void stepBackward(const MachineInstr &MI);
/// \brief Simulates liveness when stepping forward over an
/// instruction(bundle): Remove killed-uses, add defs. This is the not
/// recommended way, because it depends on accurate kill flags. If possible
/// use stepBackwards() instead of this function.
void stepForward(const MachineInstr &MI);
/// \brief Adds all live-in registers of basic block @p MBB.
void addLiveIns(const MachineBasicBlock *MBB) {
for (MachineBasicBlock::livein_iterator LI = MBB->livein_begin(),
LE = MBB->livein_end(); LI != LE; ++LI)
addReg(*LI);
}
/// \brief Adds all live-out registers of basic block @p MBB.
void addLiveOuts(const MachineBasicBlock *MBB) {
for (MachineBasicBlock::const_succ_iterator SI = MBB->succ_begin(),
SE = MBB->succ_end(); SI != SE; ++SI)
addLiveIns(*SI);
}
typedef SparseSet<unsigned>::const_iterator const_iterator;
const_iterator begin() const { return LiveRegs.begin(); }
const_iterator end() const { return LiveRegs.end(); }
/// \brief Prints the currently live registers to @p OS.
void print(raw_ostream &OS) const;
/// \brief Dumps the currently live registers to the debug output.
void dump() const;
};
inline raw_ostream &operator<<(raw_ostream &OS, const LivePhysRegs& LR) {
LR.print(OS);
return OS;
}
} // namespace llvm
#endif