//
//===----------------------------------------------------------------------===//
//
-// This file implements the LiveVariable analysis pass. For each machine
+// This file implements the LiveVariables analysis pass. For each machine
// instruction in the function, this pass calculates the set of registers that
// are immediately dead after the instruction (i.e., the instruction calculates
// the value, but it is never used) and the set of registers that are used by
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
-#include <map>
namespace llvm {
-class MRegisterInfo;
+class MachineRegisterInfo;
+class TargetRegisterInfo;
class LiveVariables : public MachineFunctionPass {
public:
/// machine instruction. Returns true if there was a kill
/// corresponding to this instruction, false otherwise.
bool removeKill(MachineInstr *MI) {
- for (std::vector<MachineInstr*>::iterator i = Kills.begin(),
- e = Kills.end(); i != e; ++i)
- if (*i == MI) {
- Kills.erase(i);
- return true;
- }
- return false;
+ std::vector<MachineInstr*>::iterator
+ I = std::find(Kills.begin(), Kills.end(), MI);
+ if (I == Kills.end())
+ return false;
+ Kills.erase(I);
+ return true;
}
void dump() const;
private: // Intermediate data structures
MachineFunction *MF;
- const MRegisterInfo *RegInfo;
-
- // PhysRegInfo - Keep track of which instruction was the last def/use of a
- // physical register. This is a purely local property, because all physical
- // register references as presumed dead across basic blocks.
- MachineInstr **PhysRegInfo;
+ MachineRegisterInfo* MRI;
- // PhysRegUsed - Keep track whether the physical register has been used after
- // its last definition. This is local property.
- bool *PhysRegUsed;
+ const TargetRegisterInfo *TRI;
- // PhysRegPartUse - Keep track of which instruction was the last partial use
- // of a physical register (e.g. on X86 a def of EAX followed by a use of AX).
- // This is a purely local property.
- MachineInstr **PhysRegPartUse;
+ // PhysRegInfo - Keep track of which instruction was the last def of a
+ // physical register. This is a purely local property, because all physical
+ // register references are presumed dead across basic blocks.
+ MachineInstr **PhysRegDef;
- // PhysRegPartDef - Keep track of a list of instructions which "partially"
- // defined the physical register (e.g. on X86 AX partially defines EAX).
- // These are turned into use/mod/write if there is a use of the register
- // later in the same block. This is local property.
- SmallVector<MachineInstr*, 4> *PhysRegPartDef;
+ // PhysRegInfo - Keep track of which instruction was the last use of a
+ // physical register. This is a purely local property, because all physical
+ // register references are presumed dead across basic blocks.
+ MachineInstr **PhysRegUse;
SmallVector<unsigned, 4> *PHIVarInfo;
- void addRegisterKills(unsigned Reg, MachineInstr *MI,
- SmallSet<unsigned, 4> &SubKills);
+ // DistanceMap - Keep track the distance of a MI from the start of the
+ // current basic block.
+ DenseMap<MachineInstr*, unsigned> DistanceMap;
/// HandlePhysRegKill - Add kills of Reg and its sub-registers to the
/// uses. Pay special attention to the sub-register uses which may come below
/// the last use of the whole register.
- bool HandlePhysRegKill(unsigned Reg, MachineInstr *MI,
- SmallSet<unsigned, 4> &SubKills);
- bool HandlePhysRegKill(unsigned Reg, MachineInstr *MI);
+ bool HandlePhysRegKill(unsigned Reg);
+
void HandlePhysRegUse(unsigned Reg, MachineInstr *MI);
void HandlePhysRegDef(unsigned Reg, MachineInstr *MI);
+ /// FindLastPartialDef - Return the last partial def of the specified register.
+ /// Also returns the sub-register that's defined.
+ MachineInstr *FindLastPartialDef(unsigned Reg, unsigned &PartDefReg);
+
+ /// hasRegisterUseBelow - Return true if the specified register is used after
+ /// the current instruction and before it's next definition.
+ bool hasRegisterUseBelow(unsigned Reg, MachineBasicBlock::iterator I,
+ MachineBasicBlock *MBB);
+
/// analyzePHINodes - Gather information about the PHI nodes in here. In
/// particular, we want to map the variable information of a virtual
/// register which is used in a PHI node. We map that to the BB the vreg
virtual bool runOnMachineFunction(MachineFunction &MF);
- /// KillsRegister - Return true if the specified instruction kills the
- /// specified register.
- bool KillsRegister(MachineInstr *MI, unsigned Reg) const;
-
/// RegisterDefIsDead - Return true if the specified instruction defines the
/// specified register, but that definition is dead.
bool RegisterDefIsDead(MachineInstr *MI, unsigned Reg) const;
- /// ModifiesRegister - Return true if the specified instruction modifies the
- /// specified register.
- bool ModifiesRegister(MachineInstr *MI, unsigned Reg) const;
-
//===--------------------------------------------------------------------===//
// API to update live variable information
/// not found.
void addVirtualRegisterKilled(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound = false) {
- if (MI->addRegisterKilled(IncomingReg, RegInfo, AddIfNotFound))
+ if (MI->addRegisterKilled(IncomingReg, TRI, AddIfNotFound))
getVarInfo(IncomingReg).Kills.push_back(MI);
}
/// AddIfNotFound is true, add a implicit operand if it's not found.
void addVirtualRegisterDead(unsigned IncomingReg, MachineInstr *MI,
bool AddIfNotFound = false) {
- if (MI->addRegisterDead(IncomingReg, RegInfo, AddIfNotFound))
+ if (MI->addRegisterDead(IncomingReg, TRI, AddIfNotFound))
getVarInfo(IncomingReg).Kills.push_back(MI);
}