[llvm] [DWARFLinker] Adjust DW_AT_LLVM_stmt_sequence for rewritten line tables (PR #128953)

[Jonas Devlieghere via llvm-commits]

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@@ -2224,22 +2263,82 @@ void DWARFLinker::DIECloner::generateLineTableForUnit(CompileUnit &Unit) {
         }
 
         // Ignore empty sequences.
-        if (Row.EndSequence && Seq.empty())
+        if (TR.Row.EndSequence && Seq.empty())
           continue;
 
         // Relocate row address and add it to the current sequence.
-        Row.Address.Address += CurrRange->Value;
-        Seq.emplace_back(Row);
+        TR.Row.Address.Address += CurrRange->Value;
+        Seq.push_back(TR);
 
-        if (Row.EndSequence)
+        if (TR.Row.EndSequence)
           insertLineSequence(Seq, NewRows);
       }
 
-      LineTable.Rows = std::move(NewRows);
+      // Materialize the tracked rows into final DWARFDebugLine::Row objects.
+      LineTable.Rows.clear();
+      LineTable.Rows.reserve(NewRows.size());
+      for (auto &TR : NewRows)
+        LineTable.Rows.push_back(TR.Row);
+
+      // Use OutputRowOffsets to store the offsets of each line table row in the
+      // output .debug_line section.
+      std::vector<uint64_t> OutputRowOffsets;
+
+      // The unit might not have any DW_AT_LLVM_stmt_sequence attributes, so use
+      // hasStmtSeq to skip the patching logic.
+      bool hasStmtSeq = Unit.getStmtSeqListAttributes().size() > 0;
+      Emitter->emitLineTableForUnit(LineTable, Unit, DebugStrPool,
+                                    DebugLineStrPool,
+                                    hasStmtSeq ? &OutputRowOffsets : nullptr);
+
+      if (hasStmtSeq) {
+        assert(OutputRowOffsets.size() == NewRows.size() &&
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JDevlieghere wrote:

Cool, I'm glad you already had the assert I was asking about. Doesn't hurt to have it in both places, but I'm also fine with having just this one. 

https://github.com/llvm/llvm-project/pull/128953