//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_CODEGEN_REGISTER_SCAVENGING_H
-#define LLVM_CODEGEN_REGISTER_SCAVENGING_H
+#ifndef LLVM_CODEGEN_REGISTERSCAVENGING_H
+#define LLVM_CODEGEN_REGISTERSCAVENGING_H
#include "llvm/ADT/BitVector.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
MachineRegisterInfo* MRI;
MachineBasicBlock *MBB;
MachineBasicBlock::iterator MBBI;
- unsigned NumPhysRegs;
+ unsigned NumRegUnits;
/// Tracking - True if RegScavenger is currently tracking the liveness of
/// registers.
bool Tracking;
- /// ScavengingFrameIndex - Special spill slot used for scavenging a register
- /// post register allocation.
- int ScavengingFrameIndex;
+ /// Information on scavenged registers (held in a spill slot).
+ struct ScavengedInfo {
+ ScavengedInfo(int FI = -1) : FrameIndex(FI), Reg(0), Restore(nullptr) {}
- /// ScavengedReg - If none zero, the specific register is currently being
- /// scavenged. That is, it is spilled to the special scavenging stack slot.
- unsigned ScavengedReg;
+ /// A spill slot used for scavenging a register post register allocation.
+ int FrameIndex;
- /// ScavengedRC - Register class of the scavenged register.
- ///
- const TargetRegisterClass *ScavengedRC;
+ /// If non-zero, the specific register is currently being
+ /// scavenged. That is, it is spilled to this scavenging stack slot.
+ unsigned Reg;
- /// ScavengeRestore - Instruction that restores the scavenged register from
- /// stack.
- const MachineInstr *ScavengeRestore;
+ /// The instruction that restores the scavenged register from stack.
+ const MachineInstr *Restore;
+ };
- /// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
- ///
- BitVector CalleeSavedRegs;
+ /// A vector of information on scavenged registers.
+ SmallVector<ScavengedInfo, 2> Scavenged;
- /// RegsAvailable - The current state of all the physical registers immediately
- /// before MBBI. One bit per physical register. If bit is set that means it's
- /// available, unset means the register is currently being used.
- BitVector RegsAvailable;
+ /// RegUnitsAvailable - The current state of each reg unit immediatelly
+ /// before MBBI. One bit per register unit. If bit is not set it means any
+ /// register containing that register unit is currently being used.
+ BitVector RegUnitsAvailable;
// These BitVectors are only used internally to forward(). They are members
// to avoid frequent reallocations.
- BitVector KillRegs, DefRegs;
+ BitVector KillRegUnits, DefRegUnits;
+ BitVector TmpRegUnits;
public:
RegScavenger()
- : MBB(NULL), NumPhysRegs(0), Tracking(false),
- ScavengingFrameIndex(-1), ScavengedReg(0), ScavengedRC(NULL) {}
+ : MBB(nullptr), NumRegUnits(0), Tracking(false) {}
/// enterBasicBlock - Start tracking liveness from the begin of the specific
/// basic block.
while (MBBI != I) forward();
}
+ /// Invert the behavior of forward() on the current instruction (undo the
+ /// changes to the available registers made by forward()).
+ void unprocess();
+
+ /// Unprocess instructions until you reach the provided iterator.
+ void unprocess(MachineBasicBlock::iterator I) {
+ while (MBBI != I) unprocess();
+ }
+
/// skipTo - Move the internal MBB iterator but do not update register states.
- ///
- void skipTo(MachineBasicBlock::iterator I) { MBBI = I; }
+ void skipTo(MachineBasicBlock::iterator I) {
+ if (I == MachineBasicBlock::iterator(nullptr))
+ Tracking = false;
+ MBBI = I;
+ }
- /// getRegsUsed - return all registers currently in use in used.
- void getRegsUsed(BitVector &used, bool includeReserved);
+ MachineBasicBlock::iterator getCurrentPosition() const {
+ return MBBI;
+ }
+
+ /// isRegUsed - return if a specific register is currently used.
+ bool isRegUsed(unsigned Reg, bool includeReserved = true) const;
/// getRegsAvailable - Return all available registers in the register class
/// in Mask.
/// Return 0 if none is found.
unsigned FindUnusedReg(const TargetRegisterClass *RegClass) const;
- /// setScavengingFrameIndex / getScavengingFrameIndex - accessor and setter of
- /// ScavengingFrameIndex.
- void setScavengingFrameIndex(int FI) { ScavengingFrameIndex = FI; }
- int getScavengingFrameIndex() const { return ScavengingFrameIndex; }
+ /// Add a scavenging frame index.
+ void addScavengingFrameIndex(int FI) {
+ Scavenged.push_back(ScavengedInfo(FI));
+ }
+
+ /// Query whether a frame index is a scavenging frame index.
+ bool isScavengingFrameIndex(int FI) const {
+ for (SmallVectorImpl<ScavengedInfo>::const_iterator I = Scavenged.begin(),
+ IE = Scavenged.end(); I != IE; ++I)
+ if (I->FrameIndex == FI)
+ return true;
+
+ return false;
+ }
+
+ /// Get an array of scavenging frame indices.
+ void getScavengingFrameIndices(SmallVectorImpl<int> &A) const {
+ for (SmallVectorImpl<ScavengedInfo>::const_iterator I = Scavenged.begin(),
+ IE = Scavenged.end(); I != IE; ++I)
+ if (I->FrameIndex >= 0)
+ A.push_back(I->FrameIndex);
+ }
/// scavengeRegister - Make a register of the specific register class
/// available and do the appropriate bookkeeping. SPAdj is the stack
return scavengeRegister(RegClass, MBBI, SPAdj);
}
- /// setUsed - Tell the scavenger a register is used.
+ /// setRegUsed - Tell the scavenger a register is used.
///
- void setUsed(unsigned Reg);
+ void setRegUsed(unsigned Reg);
private:
/// isReserved - Returns true if a register is reserved. It is never "unused".
bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
- /// isUsed - Test if a register is currently being used. When called by the
- /// isAliasUsed function, we only check isReserved if this is the original
- /// register, not an alias register.
+ /// setUsed / setUnused - Mark the state of one or a number of register units.
///
- bool isUsed(unsigned Reg, bool CheckReserved = true) const {
- return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
+ void setUsed(BitVector &RegUnits) {
+ RegUnitsAvailable.reset(RegUnits);
}
-
- /// isAliasUsed - Is Reg or an alias currently in use?
- bool isAliasUsed(unsigned Reg) const;
-
- /// setUsed / setUnused - Mark the state of one or a number of registers.
- ///
- void setUsed(BitVector &Regs) {
- RegsAvailable.reset(Regs);
+ void setUnused(BitVector &RegUnits) {
+ RegUnitsAvailable |= RegUnits;
}
- void setUnused(BitVector &Regs) {
- RegsAvailable |= Regs;
- }
-
- /// Add Reg and all its sub-registers to BV.
- void addRegWithSubRegs(BitVector &BV, unsigned Reg);
+ /// Processes the current instruction and fill the KillRegUnits and
+ /// DefRegUnits bit vectors.
+ void determineKillsAndDefs();
+
+ /// Add all Reg Units that Reg contains to BV.
+ void addRegUnits(BitVector &BV, unsigned Reg);
+
/// findSurvivorReg - Return the candidate register that is unused for the
/// longest after StartMI. UseMI is set to the instruction where the search
/// stopped.