1 files changed, 72 insertions, 40 deletions

diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 93cb7c3838e..37ff30a92a0 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -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.
@@ -127,8 +127,9 @@ class UserValue {
   SmallSet<SlotIndex, 2> trimmedDefs;
 
   /// 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.
@@ -137,8 +138,8 @@ 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) {}
 
@@ -154,8 +155,8 @@ 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;
   }
@@ -259,12 +260,14 @@ 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;}
@@ -294,11 +297,11 @@ 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.
@@ -423,8 +426,9 @@ 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();
@@ -463,11 +467,11 @@ 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));
@@ -940,15 +944,20 @@ 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) {
   // Build a set of new locations with new numbers so we can coalesce our
   // IntervalMap if two vreg intervals collapse to the same physical location.
   // Use MapVector instead of SetVector because MapVector::insert returns the
-  // position of the previously or newly inserted element.
+  // position of the previously or newly inserted element. The boolean value
+  // tracks if the location was produced by a spill.
+  // FIXME: This will be problematic if we ever support direct and indirect
+  // frame index locations, i.e. expressing both variables in memory and
+  // 'int x, *px = &x'. The "spilled" bit must become part of the location.
   MapVector<MachineOperand, bool> NewLocations;
   SmallVector<unsigned, 4> LocNoMap(locations.size());
   for (unsigned I = 0, E = locations.size(); I != E; ++I) {
+    bool Spilled = false;
     MachineOperand Loc = locations[I];
     // Only virtual registers are rewritten.
     if (Loc.isReg() && Loc.getReg() &&
@@ -963,6 +972,7 @@ void UserValue::rewriteLocations(VirtRegMap &VRM,
       } else if (VRM.getStackSlot(VirtReg) != VirtRegMap::NO_STACK_SLOT) {
         // FIXME: Translate SubIdx to a stackslot offset.
         Loc = MachineOperand::CreateFI(VRM.getStackSlot(VirtReg));
+        Spilled = true;
       } else {
         Loc.setReg(0);
         Loc.setSubReg(0);
@@ -971,14 +981,22 @@ void UserValue::rewriteLocations(VirtRegMap &VRM,
 
     // Insert this location if it doesn't already exist and record a mapping
     // from the old number to the new number.
-    auto InsertResult = NewLocations.insert({Loc, false});
-    LocNoMap[I] = std::distance(NewLocations.begin(), InsertResult.first);
+    auto InsertResult = NewLocations.insert({Loc, Spilled});
+    unsigned NewLocNo = std::distance(NewLocations.begin(), InsertResult.first);
+    LocNoMap[I] = NewLocNo;
   }
 
-  // Rewrite the locations.
+  // Rewrite the locations and record which ones were spill slots.
   locations.clear();
-  for (const auto &Pair : NewLocations)
+  SpilledLocations.clear();
+  SpilledLocations.resize(NewLocations.size());
+  for (auto &Pair : NewLocations) {
     locations.push_back(Pair.first);
+    if (Pair.second) {
+      unsigned NewLocNo = std::distance(&*NewLocations.begin(), &Pair);
+      SpilledLocations.set(NewLocNo);
+    }
+  }
 
   // Update the interval map, but only coalesce left, since intervals to the
   // right use the old location numbers. This should merge two contiguous
@@ -1016,7 +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);
@@ -1026,25 +1044,38 @@ 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);
+
+  assert((!Spilled || Loc.isFI()) &&
+         "a spilled location must be a frame index");
+
+  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
@@ -1057,7 +1088,7 @@ 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) {
@@ -1067,7 +1098,7 @@ 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)
@@ -1082,10 +1113,11 @@ 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;
 }