[DWARFYAML][debug_info] Fix array index out of bounds error

[Higuoxing]

Summary

This patch is trying to fix the array index out of bounds error. I observed it in (https://reviews.llvm.org/harbormaster/unit/view/99638/).

[Higuoxing]

I think this isn't a good approach. I will upload another revision.

[Higuoxing]

This patch gives a quick fix to the index-out-of-bounds error.

[jhenderson]

Seems reasonable to me.

I assume one of your other changes includes the test coverage for this? Could you remove the failing test case from that change, and add this change as a child, with the removed test case included? That way, your fix has an associated test case from the start. In other words, I'd reorder your dependencies: first D82073 (minus failing test) then D82139 (with test).

[Higuoxing]

Add one test.

[jhenderson]

llvm/test/tools/yaml2obj/ELF/DWARF/debug-info.yaml

558 ↗

(On Diff #272012)

Do you need a {{$}} on the end of this line? If there's more output on the same line, the test will continue to pass. Alternatively, use --match-full-lines

[Higuoxing]

Use --match-full-lines.

llvm/test/tools/yaml2obj/ELF/DWARF/debug-info.yaml

558 ↗

(On Diff #272012)

Thanks!

[jhenderson]

LGTM.

[MaskRay]

Looks great!

llvm/lib/ObjectYAML/DWARFVisitor.cpp

49

Use empty()

[MaskRay]

I removed NFC from the subject: the patch is no longer NFC due to the code change. Please adjust your local commit (arc amend should do it)

[Higuoxing]

In D82139#2103913, @MaskRay wrote:

I removed NFC from the subject: the patch is no longer NFC due to the code change. Please adjust your local commit (arc amend should do it)

Thanks!

llvm/lib/ObjectYAML/DWARFVisitor.cpp

static unsigned getRefSize(const DWARFYAML::Unit &Unit) {
   if (Unit.Version == 2)
     return Unit.AddrSize;
   return getOffsetSize(Unit);
 }
 
 template <typename T> void DWARFYAML::VisitorImpl<T>::traverseDebugInfo() {
   for (auto &Unit : DebugInfo.CompileUnits) {
     onStartCompileUnit(Unit);
+    if (Unit.Entries.size() == 0)
+      continue;
     auto FirstAbbrevCode = Unit.Entries[0].AbbrCode;
 
     for (auto &Entry : Unit.Entries) {
       onStartDIE(Unit, Entry);
       if (Entry.AbbrCode == 0u)
         continue;
       auto &Abbrev = DebugInfo.AbbrevDecls[Entry.AbbrCode - FirstAbbrevCode];
       auto FormVal = Entry.Values.begin();