mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-21 18:29:46 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11626 91177308-0d34-0410-b5e6-96231b3b80d8
280 lines
10 KiB
C++
280 lines
10 KiB
C++
//===-- llvm/CodeGen/LiveVariables.h - Live Variable Analysis ---*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file was developed by the LLVM research group and is distributed under
|
|
// the University of Illinois Open Source License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the LiveVariable 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
|
|
// the instruction, but are never used after the instruction (i.e., they are
|
|
// killed).
|
|
//
|
|
// This class computes live variables using are sparse implementation based on
|
|
// the machine code SSA form. This class computes live variable information for
|
|
// each virtual and _register allocatable_ physical register in a function. It
|
|
// uses the dominance properties of SSA form to efficiently compute live
|
|
// variables for virtual registers, and assumes that physical registers are only
|
|
// live within a single basic block (allowing it to do a single local analysis
|
|
// to resolve physical register lifetimes in each basic block). If a physical
|
|
// register is not register allocatable, it is not tracked. This is useful for
|
|
// things like the stack pointer and condition codes.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CODEGEN_LIVEVARIABLES_H
|
|
#define LLVM_CODEGEN_LIVEVARIABLES_H
|
|
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
#include <map>
|
|
|
|
namespace llvm {
|
|
|
|
class MRegisterInfo;
|
|
|
|
class LiveVariables : public MachineFunctionPass {
|
|
public:
|
|
struct VarInfo {
|
|
/// DefBlock - The basic block which defines this value...
|
|
MachineBasicBlock *DefBlock;
|
|
MachineInstr *DefInst;
|
|
|
|
/// AliveBlocks - Set of blocks of which this value is alive completely
|
|
/// through. This is a bit set which uses the basic block number as an
|
|
/// index.
|
|
///
|
|
std::vector<bool> AliveBlocks;
|
|
|
|
/// Kills - List of MachineBasicblock's which contain the last use of this
|
|
/// virtual register (kill it). This also includes the specific instruction
|
|
/// which kills the value.
|
|
///
|
|
std::vector<std::pair<MachineBasicBlock*, MachineInstr*> > Kills;
|
|
|
|
VarInfo() : DefBlock(0), DefInst(0) {}
|
|
|
|
/// removeKill - Delete a kill corresponding to the specified
|
|
/// machine instruction. Returns true if there was a kill
|
|
/// corresponding to this instruction, false otherwise.
|
|
bool removeKill(MachineInstr *MI) {
|
|
for (std::vector<std::pair<MachineBasicBlock*, MachineInstr*> >::iterator
|
|
i = Kills.begin(); i != Kills.end(); ++i) {
|
|
if (i->second == MI) {
|
|
Kills.erase(i);
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
};
|
|
|
|
private:
|
|
/// VirtRegInfo - This list is a mapping from virtual register number to
|
|
/// variable information. FirstVirtualRegister is subtracted from the virtual
|
|
/// register number before indexing into this list.
|
|
///
|
|
std::vector<VarInfo> VirtRegInfo;
|
|
|
|
/// RegistersKilled - This multimap keeps track of all of the registers that
|
|
/// are dead immediately after an instruction reads its operands. If an
|
|
/// instruction does not have an entry in this map, it kills no registers.
|
|
///
|
|
std::multimap<MachineInstr*, unsigned> RegistersKilled;
|
|
|
|
/// RegistersDead - This multimap keeps track of all of the registers that are
|
|
/// dead immediately after an instruction executes, which are not dead after
|
|
/// the operands are evaluated. In practice, this only contains registers
|
|
/// which are defined by an instruction, but never used.
|
|
///
|
|
std::multimap<MachineInstr*, unsigned> RegistersDead;
|
|
|
|
/// AllocatablePhysicalRegisters - This vector keeps track of which registers
|
|
/// are actually register allocatable by the target machine. We can not track
|
|
/// liveness for values that are not in this set.
|
|
///
|
|
std::vector<bool> AllocatablePhysicalRegisters;
|
|
|
|
private: // Intermediate data structures
|
|
|
|
/// BBMap - Maps LLVM basic blocks to their corresponding machine basic block.
|
|
/// This also provides a numbering of the basic blocks in the function.
|
|
std::map<const BasicBlock*, std::pair<MachineBasicBlock*, unsigned> > BBMap;
|
|
|
|
|
|
/// BBIdxMap - This contains the inverse mapping of BBMap, going from block ID
|
|
/// numbers to the corresponding MachineBasicBlock. This is lazily computed
|
|
/// when the getIndexMachineBasicBlock() method is called.
|
|
std::vector<MachineBasicBlock*> BBIdxMap;
|
|
|
|
const MRegisterInfo *RegInfo;
|
|
|
|
MachineInstr **PhysRegInfo;
|
|
bool *PhysRegUsed;
|
|
|
|
void HandlePhysRegUse(unsigned Reg, MachineInstr *MI);
|
|
void HandlePhysRegDef(unsigned Reg, MachineInstr *MI);
|
|
|
|
public:
|
|
|
|
virtual bool runOnMachineFunction(MachineFunction &MF);
|
|
|
|
/// getMachineBasicBlockIndex - Turn a MachineBasicBlock into an index number
|
|
/// suitable for use with VarInfo's.
|
|
///
|
|
const std::pair<MachineBasicBlock*, unsigned>
|
|
&getMachineBasicBlockInfo(MachineBasicBlock *MBB) const;
|
|
const std::pair<MachineBasicBlock*, unsigned>
|
|
&getBasicBlockInfo(const BasicBlock *BB) const {
|
|
return BBMap.find(BB)->second;
|
|
}
|
|
|
|
/// getIndexMachineBasicBlock() - Given a block index, return the
|
|
/// MachineBasicBlock corresponding to it.
|
|
MachineBasicBlock *getIndexMachineBasicBlock(unsigned Idx);
|
|
|
|
/// killed_iterator - Iterate over registers killed by a machine instruction
|
|
///
|
|
typedef std::multimap<MachineInstr*, unsigned>::iterator killed_iterator;
|
|
|
|
/// killed_begin/end - Get access to the range of registers killed by a
|
|
/// machine instruction.
|
|
killed_iterator killed_begin(MachineInstr *MI) {
|
|
return RegistersKilled.lower_bound(MI);
|
|
}
|
|
killed_iterator killed_end(MachineInstr *MI) {
|
|
return RegistersKilled.upper_bound(MI);
|
|
}
|
|
std::pair<killed_iterator, killed_iterator>
|
|
killed_range(MachineInstr *MI) {
|
|
return RegistersKilled.equal_range(MI);
|
|
}
|
|
|
|
killed_iterator dead_begin(MachineInstr *MI) {
|
|
return RegistersDead.lower_bound(MI);
|
|
}
|
|
killed_iterator dead_end(MachineInstr *MI) {
|
|
return RegistersDead.upper_bound(MI);
|
|
}
|
|
std::pair<killed_iterator, killed_iterator>
|
|
dead_range(MachineInstr *MI) {
|
|
return RegistersDead.equal_range(MI);
|
|
}
|
|
|
|
//===--------------------------------------------------------------------===//
|
|
// API to update live variable information
|
|
|
|
/// instructionChanged - When the address of an instruction changes, this
|
|
/// method should be called so that live variables can update its internal
|
|
/// data structures. This removes the records for OldMI, transfering them to
|
|
/// the records for NewMI.
|
|
void instructionChanged(MachineInstr *OldMI, MachineInstr *NewMI);
|
|
|
|
/// addVirtualRegisterKilled - Add information about the fact that the
|
|
/// specified register is killed after being used by the specified
|
|
/// instruction.
|
|
///
|
|
void addVirtualRegisterKilled(unsigned IncomingReg,
|
|
MachineBasicBlock *MBB,
|
|
MachineInstr *MI) {
|
|
RegistersKilled.insert(std::make_pair(MI, IncomingReg));
|
|
getVarInfo(IncomingReg).Kills.push_back(std::make_pair(MBB, MI));
|
|
}
|
|
|
|
/// removeVirtualRegisterKilled - Remove the specified virtual
|
|
/// register from the live variable information. Returns true if the
|
|
/// variable was marked as killed by the specified instruction,
|
|
/// false otherwise.
|
|
bool removeVirtualRegisterKilled(unsigned reg,
|
|
MachineBasicBlock *MBB,
|
|
MachineInstr *MI) {
|
|
if (!getVarInfo(reg).removeKill(MI))
|
|
return false;
|
|
for (killed_iterator i = killed_begin(MI), e = killed_end(MI); i != e; ) {
|
|
if (i->second == reg)
|
|
RegistersKilled.erase(i++);
|
|
else
|
|
++i;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// removeVirtualRegistersKilled - Remove all of the specified killed
|
|
/// registers from the live variable information.
|
|
void removeVirtualRegistersKilled(killed_iterator B, killed_iterator E) {
|
|
for (killed_iterator I = B; I != E; ++I) { // Remove VarInfo entries...
|
|
bool removed = getVarInfo(I->second).removeKill(I->first);
|
|
assert(removed && "kill not in register's VarInfo?");
|
|
}
|
|
RegistersKilled.erase(B, E);
|
|
}
|
|
|
|
/// addVirtualRegisterDead - Add information about the fact that the specified
|
|
/// register is dead after being used by the specified instruction.
|
|
///
|
|
void addVirtualRegisterDead(unsigned IncomingReg,
|
|
MachineBasicBlock *MBB,
|
|
MachineInstr *MI) {
|
|
RegistersDead.insert(std::make_pair(MI, IncomingReg));
|
|
getVarInfo(IncomingReg).Kills.push_back(std::make_pair(MBB, MI));
|
|
}
|
|
|
|
/// removeVirtualRegisterDead - Remove the specified virtual
|
|
/// register from the live variable information. Returns true if the
|
|
/// variable was marked dead at the specified instruction, false
|
|
/// otherwise.
|
|
bool removeVirtualRegisterDead(unsigned reg,
|
|
MachineBasicBlock *MBB,
|
|
MachineInstr *MI) {
|
|
if (!getVarInfo(reg).removeKill(MI))
|
|
return false;
|
|
|
|
for (killed_iterator i = killed_begin(MI), e = killed_end(MI); i != e; ) {
|
|
if (i->second == reg)
|
|
RegistersKilled.erase(i++);
|
|
else
|
|
++i;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// removeVirtualRegistersDead - Remove all of the specified dead
|
|
/// registers from the live variable information.
|
|
void removeVirtualRegistersDead(killed_iterator B, killed_iterator E) {
|
|
for (killed_iterator I = B; I != E; ++I) // Remove VarInfo entries...
|
|
getVarInfo(I->second).removeKill(I->first);
|
|
RegistersDead.erase(B, E);
|
|
}
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesAll();
|
|
}
|
|
|
|
virtual void releaseMemory() {
|
|
VirtRegInfo.clear();
|
|
RegistersKilled.clear();
|
|
RegistersDead.clear();
|
|
BBMap.clear();
|
|
BBIdxMap.clear();
|
|
}
|
|
|
|
/// getVarInfo - Return the VarInfo structure for the specified VIRTUAL
|
|
/// register.
|
|
VarInfo &getVarInfo(unsigned RegIdx);
|
|
|
|
const std::vector<bool>& getAllocatablePhysicalRegisters() const {
|
|
return AllocatablePhysicalRegisters;
|
|
}
|
|
|
|
void MarkVirtRegAliveInBlock(VarInfo &VRInfo, const BasicBlock *BB);
|
|
void HandleVirtRegUse(VarInfo &VRInfo, MachineBasicBlock *MBB,
|
|
MachineInstr *MI);
|
|
};
|
|
|
|
} // End llvm namespace
|
|
|
|
#endif
|