DebugInfo: Use loclistx for DWARFv5 location lists to reduce the number of relocations

This only implements the non-dwo part, but loclistx is necessary to use
location lists in DWARFv5, so it's a precursor to that work - and
generally reduces relocations (only using one reloc, then
indexes/relative offsets for all location list references) in non-split
DWARF.

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index 49a7f7dc2a5..7fa72b1bb57 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -96,6 +96,13 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
 
     uint64_t Offset = *FormValue.getAsSectionOffset();
 
+    if (FormValue.getForm() == DW_FORM_loclistx) {
+      FormValue.dump(OS, DumpOpts);
+      if (auto LoclistOffset = U->getLoclistOffset(Offset))
+        Offset = *LoclistOffset + U->getLocSectionBase();
+      else
+        return;
+    }
     U->getLocationTable().dumpLocationList(&Offset, OS, U->getBaseAddress(),
                                            MRI, U, LLDumpOpts, Indent);
     return;
@@ -409,6 +416,10 @@ Optional<uint64_t> DWARFDie::getRangesBaseAttribute() const {
   return toSectionOffset(find({DW_AT_rnglists_base, DW_AT_GNU_ranges_base}));
 }
 
+Optional<uint64_t> DWARFDie::getLocBaseAttribute() const {
+  return toSectionOffset(find(DW_AT_loclists_base));
+}
+
 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
   if (auto FormValue = find(DW_AT_high_pc)) {
     if (auto Address = FormValue->getAsAddress()) {