// \brief Terminate the location range for variables described by register
// @RegNo by inserting @ClobberingInstr to their history.
static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
DbgValueHistoryMap &HistMap,
const MachineInstr &ClobberingInstr) {
const auto &I = RegVars.find(RegNo);
if (I == RegVars.end())
return;
clobberRegisterUses(RegVars, I, HistMap, ClobberingInstr);
}
// \brief Claim that @Var is not described by @RegNo anymore.
static void dropRegDescribedVar(RegDescribedVarsMap &RegVars, unsigned RegNo,
InlinedVariable Var) {
const auto &I = RegVars.find(RegNo);
assert(RegNo != 0U && I != RegVars.end());
auto &VarSet = I->second;
const auto &VarPos = std::find(VarSet.begin(), VarSet.end(), Var);
assert(VarPos != VarSet.end());
VarSet.erase(VarPos);
// Don't keep empty sets in a map to keep it as small as possible.
if (VarSet.empty())
RegVars.erase(I);
}
// \brief Terminate the location range for variables described by register
// @RegNo by inserting @ClobberingInstr to their history.
static void clobberRegisterUses(RegDescribedVarsMap &RegVars, unsigned RegNo,
DbgValueHistoryMap &HistMap,
const MachineInstr &ClobberingInstr) {
const auto &I = RegVars.find(RegNo);
if (I == RegVars.end())
return;
// Iterate over all variables described by this register and add this
// instruction to their history, clobbering it.
for (const auto &Var : I->second)
clobberVariableLocation(HistMap[Var], ClobberingInstr);
RegVars.erase(I);
}
void llvm::calculateDbgValueHistory(const MachineFunction *MF,
const TargetRegisterInfo *TRI,
DbgValueHistoryMap &Result) {
BitVector ChangingRegs(TRI->getNumRegs());
collectChangingRegs(MF, TRI, ChangingRegs);
RegDescribedVarsMap RegVars;
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (!MI.isDebugValue()) {
// Not a DBG_VALUE instruction. It may clobber registers which describe
// some variables.
applyToClobberedRegisters(MI, TRI, [&](unsigned RegNo) {
if (ChangingRegs.test(RegNo))
clobberRegisterUses(RegVars, RegNo, Result, MI);
});
continue;
}
assert(MI.getNumOperands() > 1 && "Invalid DBG_VALUE instruction!");
// Use the base variable (without any DW_OP_piece expressions)
// as index into History. The full variables including the
// piece expressions are attached to the MI.
const DILocalVariable *RawVar = MI.getDebugVariable();
assert(RawVar->isValidLocationForIntrinsic(MI.getDebugLoc()) &&
"Expected inlined-at fields to agree");
InlinedVariable Var(RawVar, MI.getDebugLoc()->getInlinedAt());
if (unsigned PrevReg = Result.getRegisterForVar(Var))
dropRegDescribedVar(RegVars, PrevReg, Var);
Result.startInstrRange(Var, MI);
if (unsigned NewReg = isDescribedByReg(MI))
addRegDescribedVar(RegVars, NewReg, Var);
}
// Make sure locations for register-described variables are valid only
// until the end of the basic block (unless it's the last basic block, in
// which case let their liveness run off to the end of the function).
if (!MBB.empty() && &MBB != &MF->back()) {
for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {
auto CurElem = I++; // CurElem can be erased below.
if (ChangingRegs.test(CurElem->first))
clobberRegisterUses(RegVars, CurElem, Result, MBB.back());
}
}
}
}
void llvm::calculateDbgValueHistory(const MachineFunction *MF,
const TargetRegisterInfo *TRI,
DbgValueHistoryMap &Result) {
BitVector ChangingRegs(TRI->getNumRegs());
collectChangingRegs(MF, TRI, ChangingRegs);
const TargetLowering *TLI = MF->getSubtarget().getTargetLowering();
unsigned SP = TLI->getStackPointerRegisterToSaveRestore();
RegDescribedVarsMap RegVars;
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (!MI.isDebugValue()) {
// Not a DBG_VALUE instruction. It may clobber registers which describe
// some variables.
for (const MachineOperand &MO : MI.operands()) {
if (MO.isReg() && MO.isDef() && MO.getReg()) {
// If this is a virtual register, only clobber it since it doesn't
// have aliases.
if (TRI->isVirtualRegister(MO.getReg()))
clobberRegisterUses(RegVars, MO.getReg(), Result, MI);
// If this is a register def operand, it may end a debug value
// range.
else {
for (MCRegAliasIterator AI(MO.getReg(), TRI, true); AI.isValid();
++AI)
if (ChangingRegs.test(*AI))
clobberRegisterUses(RegVars, *AI, Result, MI);
}
} else if (MO.isRegMask()) {
// If this is a register mask operand, clobber all debug values in
// non-CSRs.
for (int I = ChangingRegs.find_first(); I != -1;
I = ChangingRegs.find_next(I)) {
// Don't consider SP to be clobbered by register masks.
if (unsigned(I) != SP && TRI->isPhysicalRegister(I) &&
MO.clobbersPhysReg(I)) {
clobberRegisterUses(RegVars, I, Result, MI);
}
}
}
}
continue;
}
assert(MI.getNumOperands() > 1 && "Invalid DBG_VALUE instruction!");
// Use the base variable (without any DW_OP_piece expressions)
// as index into History. The full variables including the
// piece expressions are attached to the MI.
const DILocalVariable *RawVar = MI.getDebugVariable();
assert(RawVar->isValidLocationForIntrinsic(MI.getDebugLoc()) &&
"Expected inlined-at fields to agree");
InlinedVariable Var(RawVar, MI.getDebugLoc()->getInlinedAt());
if (unsigned PrevReg = Result.getRegisterForVar(Var))
dropRegDescribedVar(RegVars, PrevReg, Var);
Result.startInstrRange(Var, MI);
if (unsigned NewReg = isDescribedByReg(MI))
addRegDescribedVar(RegVars, NewReg, Var);
}
// Make sure locations for register-described variables are valid only
// until the end of the basic block (unless it's the last basic block, in
// which case let their liveness run off to the end of the function).
if (!MBB.empty() && &MBB != &MF->back()) {
for (auto I = RegVars.begin(), E = RegVars.end(); I != E;) {
auto CurElem = I++; // CurElem can be erased below.
if (TRI->isVirtualRegister(CurElem->first) ||
ChangingRegs.test(CurElem->first))
clobberRegisterUses(RegVars, CurElem, Result, MBB.back());
}
}
}
}