[PATCH] D151579: Fix -u option in dsymutil, to not emit an extra DW_LNE_set_address if the original line table was empty

[Alexey Lapshin via Phabricator via llvm-commits]

avl added inline comments.


================
Comment at: llvm/lib/DWARFLinker/DWARFStreamer.cpp:854-855
 
-  if (LineTable.Rows.empty()) {
+  if (LineTable.Rows.empty() ||
+      (LineTable.Rows.size() == 1 && LineTable.Rows[0].EndSequence)) {
     // We only have the dummy entry, dsymutil emits an entry with a 0
----------------
JDevlieghere wrote:
> Would it make sense to hoist that into the `LineTable` class and have a method `LineTable::empty()` that returns exactly this? 
In that case LineTable::empty() would in fact not match with real number of LineTable.Rows(). It looks a bit sloppy.


Another alternative might be implementing what described in DWARFLinker.cpp:

  // FIXME: this only removes the unneeded end_sequence if the
  // sequences have been inserted in order. Using a global sort like
  // described in generateLineTableForUnit() and delaying the end_sequene
  // elimination to emitLineTableForUnit() we can get rid of all of them.

Running such cleanup code for no-update and update modes will probably make output equal for both modes.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151579/new/

https://reviews.llvm.org/D151579