[llvm] [DwarfDump] Add new set of line-table-related statistics to llvm-dwarfdump (PR #93289)

[Felipe de Azevedo Piovezan via llvm-commits]

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@@ -882,8 +902,58 @@ bool dwarfdump::collectStatsForObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
         CrossCUReferencesToBeResolved.push_back(
             DIELocation(CUDie.getDwarfUnit(), CrossCUReferencingDIEOffset));
     }
+    const auto *LineTable = DICtx.getLineTableForUnit(CU.get());
+    std::optional<uint64_t> LastFileIdxOpt;
+    if (LineTable)
+      LastFileIdxOpt = LineTable->getLastValidFileIndex();
+    if (LastFileIdxOpt) {
+      // Each CU has its own file index; in order to track unique line entries
+      // across CUs, we therefore need to map each CU file index to a global
+      // file index, which we store here.
+      DenseMap<uint64_t, uint16_t> CUFileMapping;
+      std::string File;
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felipepiovezan wrote:

The scope of this variable can be restricted to being inside the loop, right now this is giving the impression it is needed across loop iterations or outside the loop

https://github.com/llvm/llvm-project/pull/93289