//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_CODEGEN_REGISTER_SCAVENGING_H
-#define LLVM_CODEGEN_REGISTER_SCAVENGING_H
+#ifndef LLVM_CODEGEN_REGISTERSCAVENGING_H
+#define LLVM_CODEGEN_REGISTERSCAVENGING_H
-#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/ADT/BitVector.h"
+#include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
namespace llvm {
/// 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(NULL) {}
- /// 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;
+
+ /// The instruction that restores the scavenged register from stack.
+ const MachineInstr *Restore;
+ };
- /// ScavengeRestore - Instruction that restores the scavenged register from
- /// stack.
- const MachineInstr *ScavengeRestore;
+ /// A vector of information on scavenged registers.
+ SmallVector<ScavengedInfo, 2> Scavenged;
/// CalleeSavedrRegs - A bitvector of callee saved registers for the target.
///
BitVector CalleeSavedRegs;
- /// ReservedRegs - A bitvector of reserved registers.
- ///
- BitVector ReservedRegs;
-
/// 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;
+ // These BitVectors are only used internally to forward(). They are members
+ // to avoid frequent reallocations.
+ BitVector KillRegs, DefRegs;
+
public:
RegScavenger()
- : MBB(NULL), NumPhysRegs(0), Tracking(false),
- ScavengingFrameIndex(-1), ScavengedReg(0), ScavengedRC(NULL) {}
+ : MBB(NULL), NumPhysRegs(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(NULL))
+ Tracking = false;
+ MBBI = I;
+ }
+
+ MachineBasicBlock::iterator getCurrentPosition() const {
+ return MBBI;
+ }
/// getRegsUsed - return all registers currently in use in used.
void getRegsUsed(BitVector &used, bool includeReserved);
- /// FindUnusedReg - Find a unused register of the specified register class
- /// from the specified set of registers. It return 0 is none is found.
- unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
- const BitVector &Candidates) const;
+ /// getRegsAvailable - Return all available registers in the register class
+ /// in Mask.
+ BitVector getRegsAvailable(const TargetRegisterClass *RC);
/// FindUnusedReg - Find a unused register of the specified register class.
- /// Exclude callee saved registers if directed. It return 0 is none is found.
- unsigned FindUnusedReg(const TargetRegisterClass *RegClass,
- bool ExCalleeSaved = false) const;
+ /// 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.
+ ///
+ void setUsed(unsigned Reg);
private:
/// isReserved - Returns true if a register is reserved. It is never "unused".
- bool isReserved(unsigned Reg) const { return ReservedRegs.test(Reg); }
+ bool isReserved(unsigned Reg) const { return MRI->isReserved(Reg); }
- /// isUsed / isUsed - Test if a register is currently being used.
+ /// 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.
///
- bool isUsed(unsigned Reg) const { return !RegsAvailable.test(Reg); }
- bool isUnused(unsigned Reg) const { return RegsAvailable.test(Reg); }
+ bool isUsed(unsigned Reg, bool CheckReserved = true) const {
+ return !RegsAvailable.test(Reg) || (CheckReserved && isReserved(Reg));
+ }
/// 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(unsigned Reg);
void setUsed(BitVector &Regs) {
- RegsAvailable &= ~Regs;
+ RegsAvailable.reset(Regs);
}
void setUnused(BitVector &Regs) {
RegsAvailable |= Regs;
}
+ /// Processes the current instruction and fill the KillRegs and DefRegs bit
+ /// vectors.
+ void determineKillsAndDefs();
+
/// Add Reg and all its sub-registers to BV.
void addRegWithSubRegs(BitVector &BV, unsigned Reg);
- /// Add Reg and its aliases to BV.
- void addRegWithAliases(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.
+ ///
+ /// No more than InstrLimit instructions are inspected.
+ unsigned findSurvivorReg(MachineBasicBlock::iterator StartMI,
+ BitVector &Candidates,
+ unsigned InstrLimit,
+ MachineBasicBlock::iterator &UseMI);
+
};
} // End llvm namespace
projects / oota-llvm.git / blobdiff