Fix Debug Info after removing stack slot

Author: mohammed-nurulhoque

llvm/lib/CodeGen/StackColoring.cpp

@@ -899,6 +899,13 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
   unsigned FixedMemOp = 0;
   unsigned FixedDbg = 0;
 
+  // Remove debug information for deleted slots.
+  erase_if(MF->getVariableDbgInfo(), [&](auto &VI) {
+    int Slot = VI.getStackSlot();
+    return Slot >= 0 && Intervals[Slot]->empty() &&
+           InterestingSlots.test(Slot) && !ConservativeSlots.test(Slot);
+  });
+
   // Remap debug information that refers to stack slots.
   for (auto &VI : MF->getVariableDbgInfo()) {
     if (!VI.Var || !VI.inStackSlot())

llvm/test/DebugInfo/COFF/lexicalblock.ll

@@ -63,32 +63,12 @@
 ; CHECK: LocalSym {
 ; CHECK:   VarName: localA
 ; CHECK: }
-; CHECK: LocalSym {
-; CHECK:   VarName: localB
-; CHECK: }
-; CHECK: BlockSym {
-; CHECK:   Kind: S_BLOCK32 {{.*}}
-; CHECK:   BlockName: 
-; CHECK: }
-; CHECK: ScopeEndSym {
-; CHECK:   Kind: S_END {{.*}}
-; CHECK: }
-; CHECK: BlockSym {
-; CHECK:   Kind: S_BLOCK32 {{.*}}
-; CHECK:   BlockName: 
-; CHECK: }
-; CHECK: ScopeEndSym {
-; CHECK:   Kind: S_END {{.*}}
-; CHECK: }
 ; CHECK: BlockSym {
 ; CHECK:   Kind: S_BLOCK32 {{.*}}
 ; CHECK:   BlockName: 
 ; CHECK: }
-; CHECK: ScopeEndSym {
-; CHECK: }
-; CHECK: BlockSym {
-; CHECK:   Kind: S_BLOCK32 {{.*}}
-; CHECK:   BlockName: 
+; CHECK: LocalSym {
+; CHECK:   VarName: localB
 ; CHECK: }
 ; CHECK: ScopeEndSym {
 ; CHECK:   Kind: S_END {{.*}}