Update LiveDebugVariables after live range splitting.
After a virtual register is split, update any debug user variables that resided
in the old register. This ensures that the LiveDebugVariables are still correct
after register allocation.
This may create DBG_VALUE instructions that place a user variable in a register
in parts of the function and in a stack slot in other parts. DwarfDebug
currently doesn't support that.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130998 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/LiveDebugVariables.cpp b/lib/CodeGen/LiveDebugVariables.cpp
index 24b268a..41bf87f 100644
--- a/lib/CodeGen/LiveDebugVariables.cpp
+++ b/lib/CodeGen/LiveDebugVariables.cpp
@@ -101,9 +101,13 @@
void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
LiveIntervals &LIS, const TargetInstrInfo &TII);
+ /// splitLocation - Replace OldLocNo ranges with NewRegs ranges where NewRegs
+ /// is live. Returns true if any changes were made.
+ bool splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
+
public:
/// UserValue - Create a new UserValue.
- UserValue(const MDNode *var, unsigned o, DebugLoc L,
+ UserValue(const MDNode *var, unsigned o, DebugLoc L,
LocMap::Allocator &alloc)
: variable(var), offset(o), dl(L), leader(this), next(0), locInts(alloc)
{}
@@ -215,6 +219,10 @@
void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx,
const TargetRegisterInfo *TRI);
+ /// splitRegister - Replace OldReg ranges with NewRegs ranges where NewRegs is
+ /// live. Returns true if any changes were made.
+ bool splitRegister(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs);
+
/// rewriteLocations - Rewrite virtual register locations according to the
/// provided virtual register map.
void rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI);
@@ -293,6 +301,9 @@
/// renameRegister - Replace all references to OldReg with NewReg:SubIdx.
void renameRegister(unsigned OldReg, unsigned NewReg, unsigned SubIdx);
+ /// splitRegister - Replace all references to OldReg with NewRegs.
+ void splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs);
+
/// emitDebugVariables - Recreate DBG_VALUE instruction from data structures.
void emitDebugValues(VirtRegMap *VRM);
@@ -679,6 +690,140 @@
static_cast<LDVImpl*>(pImpl)->renameRegister(OldReg, NewReg, SubIdx);
}
+//===----------------------------------------------------------------------===//
+// Live Range Splitting
+//===----------------------------------------------------------------------===//
+
+bool
+UserValue::splitLocation(unsigned OldLocNo, ArrayRef<LiveInterval*> NewRegs) {
+ DEBUG({
+ dbgs() << "Splitting Loc" << OldLocNo << '\t';
+ print(dbgs(), 0);
+ });
+ bool DidChange = false;
+ LocMap::iterator LocMapI;
+ LocMapI.setMap(locInts);
+ for (unsigned i = 0; i != NewRegs.size(); ++i) {
+ LiveInterval *LI = NewRegs[i];
+ if (LI->empty())
+ continue;
+
+ // Don't allocate the new LocNo until it is needed.
+ unsigned NewLocNo = ~0u;
+
+ // Iterate over the overlaps between locInts and LI.
+ LocMapI.find(LI->beginIndex());
+ if (!LocMapI.valid())
+ continue;
+ LiveInterval::iterator LII = LI->advanceTo(LI->begin(), LocMapI.start());
+ LiveInterval::iterator LIE = LI->end();
+ while (LocMapI.valid() && LII != LIE) {
+ // At this point, we know that LocMapI.stop() > LII->start.
+ LII = LI->advanceTo(LII, LocMapI.start());
+ if (LII == LIE)
+ break;
+
+ // Now LII->end > LocMapI.start(). Do we have an overlap?
+ if (LocMapI.value() == OldLocNo && LII->start < LocMapI.stop()) {
+ // Overlapping correct location. Allocate NewLocNo now.
+ if (NewLocNo == ~0u) {
+ MachineOperand MO = MachineOperand::CreateReg(LI->reg, false);
+ MO.setSubReg(locations[OldLocNo].getSubReg());
+ NewLocNo = getLocationNo(MO);
+ DidChange = true;
+ }
+
+ SlotIndex LStart = LocMapI.start();
+ SlotIndex LStop = LocMapI.stop();
+
+ // Trim LocMapI down to the LII overlap.
+ if (LStart < LII->start)
+ LocMapI.setStartUnchecked(LII->start);
+ if (LStop > LII->end)
+ LocMapI.setStopUnchecked(LII->end);
+
+ // Change the value in the overlap. This may trigger coalescing.
+ LocMapI.setValue(NewLocNo);
+
+ // Re-insert any removed OldLocNo ranges.
+ if (LStart < LocMapI.start()) {
+ LocMapI.insert(LStart, LocMapI.start(), OldLocNo);
+ ++LocMapI;
+ assert(LocMapI.valid() && "Unexpected coalescing");
+ }
+ if (LStop > LocMapI.stop()) {
+ ++LocMapI;
+ LocMapI.insert(LII->end, LStop, OldLocNo);
+ --LocMapI;
+ }
+ }
+
+ // Advance to the next overlap.
+ if (LII->end < LocMapI.stop()) {
+ if (++LII == LIE)
+ break;
+ LocMapI.advanceTo(LII->start);
+ } else {
+ ++LocMapI;
+ if (!LocMapI.valid())
+ break;
+ LII = LI->advanceTo(LII, LocMapI.start());
+ }
+ }
+ }
+
+ // Finally, remove any remaining OldLocNo intervals and OldLocNo itself.
+ locations.erase(locations.begin() + OldLocNo);
+ LocMapI.goToBegin();
+ while (LocMapI.valid()) {
+ unsigned v = LocMapI.value();
+ if (v == OldLocNo) {
+ DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';'
+ << LocMapI.stop() << ")\n");
+ LocMapI.erase();
+ } else {
+ if (v > OldLocNo)
+ LocMapI.setValueUnchecked(v-1);
+ ++LocMapI;
+ }
+ }
+
+ DEBUG({dbgs() << "Split result: \t"; print(dbgs(), 0);});
+ return DidChange;
+}
+
+bool
+UserValue::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
+ bool DidChange = false;
+ for (unsigned LocNo = 0, E = locations.size(); LocNo != E; ++LocNo) {
+ const MachineOperand *Loc = &locations[LocNo];
+ if (!Loc->isReg() || Loc->getReg() != OldReg)
+ continue;
+ DidChange |= splitLocation(LocNo, NewRegs);
+ }
+ return DidChange;
+}
+
+void LDVImpl::splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
+ bool DidChange = false;
+ for (UserValue *UV = lookupVirtReg(OldReg); UV; UV = UV->getNext())
+ DidChange |= UV->splitRegister(OldReg, NewRegs);
+
+ if (!DidChange)
+ return;
+
+ // Map all of the new virtual registers.
+ UserValue *UV = lookupVirtReg(OldReg);
+ for (unsigned i = 0; i != NewRegs.size(); ++i)
+ mapVirtReg(NewRegs[i]->reg, UV);
+}
+
+void LiveDebugVariables::
+splitRegister(unsigned OldReg, ArrayRef<LiveInterval*> NewRegs) {
+ if (pImpl)
+ static_cast<LDVImpl*>(pImpl)->splitRegister(OldReg, NewRegs);
+}
+
void
UserValue::rewriteLocations(VirtRegMap &VRM, const TargetRegisterInfo &TRI) {
// Iterate over locations in reverse makes it easier to handle coalescing.