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Re-land r313400 "[DebugInfo] Insert DW_OP_deref when spilling indirect DBG_VALUEs"

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I forgot to zero out the BitVector when reusing it between UserValues.

Later uses of the same location number for a different UserValue would
falsely indicate that they were spilled. Usually this would lead to
incorrect debug info, but in some cases they would indicate something
nonsensical like a memory location based on a vector register (Q8 on
ARM).

llvm-svn: 313640
This commit is contained in:
Reid Kleckner
2017-09-19 16:32:15 +00:00
parent 2d9c5f3b8b
commit 86c74dd791
5 changed files with 362 additions and 38 deletions
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89
llvm/lib/CodeGen/LiveDebugVariables.cpp
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@@ -108,8 +108,8 @@ class LDVImpl;
/// held by the same virtual register. The equivalence class is the transitive
/// closure of that relation.
class UserValue {
const MDNode *Variable; ///< The debug info variable we are part of.
const MDNode *Expression; ///< Any complex address expression.
const DILocalVariable *Variable; ///< The debug info variable we are part of.
const DIExpression *Expression; ///< Any complex address expression.
bool IsIndirect; ///< true if this is a register-indirect+offset value.
DebugLoc dl; ///< The debug location for the variable. This is
///< used by dwarf writer to find lexical scope.
@@ -132,8 +132,9 @@ class UserValue {
void coalesceLocation(unsigned LocNo);
/// insertDebugValue - Insert a DBG_VALUE into MBB at Idx for LocNo.
void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
LiveIntervals &LIS, const TargetInstrInfo &TII);
void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
unsigned LocNo, bool Spilled, LiveIntervals &LIS,
const TargetInstrInfo &TII);
/// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
/// is live. Returns true if any changes were made.
@@ -142,8 +143,8 @@ class UserValue {
public:
/// UserValue - Create a new UserValue.
UserValue(const MDNode *var, const MDNode *expr, bool i, DebugLoc L,
LocMap::Allocator &alloc)
UserValue(const DILocalVariable *var, const DIExpression *expr, bool i,
DebugLoc L, LocMap::Allocator &alloc)
: Variable(var), Expression(expr), IsIndirect(i), dl(std::move(L)),
leader(this), locInts(alloc) {}
@@ -159,8 +160,8 @@ public:
UserValue *getNext() const { return next; }
/// match - Does this UserValue match the parameters?
bool match(const MDNode *Var, const MDNode *Expr, const DILocation *IA,
bool indirect) const {
bool match(const DILocalVariable *Var, const DIExpression *Expr,
const DILocation *IA, bool indirect) const {
return Var == Variable && Expr == Expression && dl->getInlinedAt() == IA &&
indirect == IsIndirect;
}
@@ -264,12 +265,14 @@ public:
LiveIntervals &LIS);
/// rewriteLocations - Rewrite virtual register locations according to the
/// provided virtual register map.
void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
/// provided virtual register map. Record which locations were spilled.
void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
BitVector &SpilledLocations);
/// emitDebugValues - Recreate DBG_VALUE instruction from data structures.
void emitDebugValues(VirtRegMap *VRM,
LiveIntervals &LIS, const TargetInstrInfo &TRI);
void emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
const TargetInstrInfo &TRI,
const BitVector &SpilledLocations);
/// getDebugLoc - Return DebugLoc of this UserValue.
DebugLoc getDebugLoc() { return dl;}
@@ -299,11 +302,11 @@ class LDVImpl {
VRMap virtRegToEqClass;
/// Map user variable to eq class leader.
using UVMap = DenseMap<const MDNode *, UserValue *>;
using UVMap = DenseMap<const DILocalVariable *, UserValue *>;
UVMap userVarMap;
/// getUserValue - Find or create a UserValue.
UserValue *getUserValue(const MDNode *Var, const MDNode *Expr,
UserValue *getUserValue(const DILocalVariable *Var, const DIExpression *Expr,
bool IsIndirect, const DebugLoc &DL);
/// lookupVirtReg - Find the EC leader for VirtReg or null.
@@ -456,8 +459,9 @@ void UserValue::mapVirtRegs(LDVImpl *LDV) {
LDV->mapVirtReg(locations[i].getReg(), this);
}
UserValue *LDVImpl::getUserValue(const MDNode *Var, const MDNode *Expr,
bool IsIndirect, const DebugLoc &DL) {
UserValue *LDVImpl::getUserValue(const DILocalVariable *Var,
const DIExpression *Expr, bool IsIndirect,
const DebugLoc &DL) {
UserValue *&Leader = userVarMap[Var];
if (Leader) {
UserValue *UV = Leader->getLeader();
@@ -496,11 +500,11 @@ bool LDVImpl::handleDebugValue(MachineInstr &MI, SlotIndex Idx) {
}
// Get or create the UserValue for (variable,offset).
bool IsIndirect = MI.isIndirectDebugValue();
bool IsIndirect = MI.getOperand(1).isImm();
if (IsIndirect)
assert(MI.getOperand(1).getImm() == 0 && "DBG_VALUE with nonzero offset");
const MDNode *Var = MI.getDebugVariable();
const MDNode *Expr = MI.getDebugExpression();
const DILocalVariable *Var = MI.getDebugVariable();
const DIExpression *Expr = MI.getDebugExpression();
//here.
UserValue *UV = getUserValue(Var, Expr, IsIndirect, MI.getDebugLoc());
UV->addDef(Idx, MI.getOperand(0));
@@ -973,8 +977,11 @@ splitRegister(unsigned OldReg, ArrayRef<unsigned> NewRegs, LiveIntervals &LIS) {
static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
}
void
UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
void UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI,
BitVector &SpilledLocations) {
SpilledLocations.clear();
SpilledLocations.resize(locations.size());
// Iterate over locations in reverse makes it easier to handle coalescing.
for (unsigned i = locations.size(); i ; --i) {
unsigned LocNo = i-1;
@@ -993,6 +1000,7 @@ UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
} else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
// FIXME: Translate SubIdx to a stackslot offset.
Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
SpilledLocations.set(LocNo);
} else {
Loc.setReg(0);
Loc.setSubReg(0);
@@ -1026,7 +1034,7 @@ findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx,
}
void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
unsigned LocNo,
unsigned LocNo, bool Spilled,
LiveIntervals &LIS,
const TargetInstrInfo &TII) {
MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
@@ -1036,25 +1044,35 @@ void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
assert(cast<DILocalVariable>(Variable)
->isValidLocationForIntrinsic(getDebugLoc()) &&
"Expected inlined-at fields to agree");
if (Loc.isReg())
BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE),
IsIndirect, Loc.getReg(), Variable, Expression);
// If the location was spilled, the new DBG_VALUE will be indirect. If the
// original DBG_VALUE was indirect, we need to add DW_OP_deref to indicate
// that the original virtual register was a pointer.
bool NewIndirect = IsIndirect || Spilled;
const DIExpression *Expr = Expression;
if (Spilled && IsIndirect)
Expr = DIExpression::prepend(Expr, DIExpression::WithDeref);
MachineInstrBuilder MIB =
BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
.add(Loc);
if (NewIndirect)
MIB.addImm(0U);
else
BuildMI(*MBB, I, getDebugLoc(), TII.get(TargetOpcode::DBG_VALUE))
.add(Loc)
.addImm(0U)
.addMetadata(Variable)
.addMetadata(Expression);
MIB.addReg(0U, RegState::Debug);
MIB.addMetadata(Variable).addMetadata(Expr);
}
void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
const TargetInstrInfo &TII) {
const TargetInstrInfo &TII,
const BitVector &SpilledLocations) {
MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
for (LocMap::const_iterator I = locInts.begin(); I.valid();) {
SlotIndex Start = I.start();
SlotIndex Stop = I.stop();
unsigned LocNo = I.value();
bool Spilled = LocNo != UndefLocNo ? SpilledLocations.test(LocNo) : false;
// If the interval start was trimmed to the lexical scope insert the
// DBG_VALUE at the previous index (otherwise it appears after the
@@ -1067,7 +1085,7 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
SlotIndex MBBEnd = LIS.getMBBEndIdx(&*MBB);
DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
insertDebugValue(&*MBB, Start, LocNo, LIS, TII);
insertDebugValue(&*MBB, Start, LocNo, Spilled, LIS, TII);
// This interval may span multiple basic blocks.
// Insert a DBG_VALUE into each one.
while(Stop > MBBEnd) {
@@ -1077,7 +1095,7 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
break;
MBBEnd = LIS.getMBBEndIdx(&*MBB);
DEBUG(dbgs() << " BB#" << MBB->getNumber() << '-' << MBBEnd);
insertDebugValue(&*MBB, Start, LocNo, LIS, TII);
insertDebugValue(&*MBB, Start, LocNo, Spilled, LIS, TII);
}
DEBUG(dbgs() << '\n');
if (MBB == MFEnd)
@@ -1092,10 +1110,11 @@ void LDVImpl::emitDebugValues(VirtRegMap *VRM) {
if (!MF)
return;
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
BitVector SpilledLocations;
for (unsigned i = 0, e = userValues.size(); i != e; ++i) {
DEBUG(userValues[i]->print(dbgs(), TRI));
userValues[i]->rewriteLocations(*VRM, *TRI);
userValues[i]->emitDebugValues(VRM, *LIS, *TII);
userValues[i]->rewriteLocations(*VRM, *TRI, SpilledLocations);
userValues[i]->emitDebugValues(VRM, *LIS, *TII, SpilledLocations);
}
EmitDone = true;
}