[llvm-dwp] Abort when dwo_id is unset

Summary:
An empty dwo_id indicates a degenerate .dwo file that should not have been generated in the first place. Instead of discovering this error later when merging with another degenerate .dwo file, print an error immediately when noticing an unset dwo_id, including the filename of the offending file.

Test case created by compiling a trivial file w/ `-fno-split-dwarf-inlining -gmlt -gsplit-dwarf -c` prior to r353771

Reviewers: dblaikie

Reviewed By: dblaikie

Subscribers: jdoerfert, aprantl, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58085

llvm-svn: 353846

1 files changed, 8 insertions, 3 deletions

diff --git a/llvm/tools/llvm-dwp/llvm-dwp.cpp b/llvm/tools/llvm-dwp/llvm-dwp.cpp
index cb4df9fd49f..87831a8f81f 100644
--- a/llvm/tools/llvm-dwp/llvm-dwp.cpp
+++ b/llvm/tools/llvm-dwp/llvm-dwp.cpp
@@ -13,6 +13,7 @@
 #include "DWPError.h"
 #include "DWPStringPool.h"
 #include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
@@ -159,6 +160,7 @@ static Expected<CompileUnitIdentifiers> getCUIdentifiers(StringRef Abbrev,
   uint32_t Name;
   dwarf::Form Form;
   CompileUnitIdentifiers ID;
+  Optional<uint64_t> Signature = None;
   while ((Name = AbbrevData.getULEB128(&AbbrevOffset)) |
          (Form = static_cast<dwarf::Form>(AbbrevData.getULEB128(&AbbrevOffset))) &&
          (Name != 0 || Form != 0)) {
@@ -180,13 +182,16 @@ static Expected<CompileUnitIdentifiers> getCUIdentifiers(StringRef Abbrev,
       break;
     }
     case dwarf::DW_AT_GNU_dwo_id:
-      ID.Signature = InfoData.getU64(&Offset);
+      Signature = InfoData.getU64(&Offset);
       break;
     default:
       DWARFFormValue::skipValue(Form, InfoData, &Offset,
                                 dwarf::FormParams({Version, AddrSize, Format}));
     }
   }
+  if (!Signature)
+    return make_error<DWPError>("compile unit missing dwo_id");
+  ID.Signature = *Signature;
   return ID;
 }
 
@@ -560,7 +565,7 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
       Expected<CompileUnitIdentifiers> EID = getCUIdentifiers(
           AbbrevSection, InfoSection, CurStrOffsetSection, CurStrSection);
       if (!EID)
-        return EID.takeError();
+        return createFileError(Input, EID.takeError());
       const auto &ID = *EID;
       auto P = IndexEntries.insert(std::make_pair(ID.Signature, CurEntry));
       if (!P.second)
@@ -588,7 +593,7 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
           getSubsection(CurStrOffsetSection, E, DW_SECT_STR_OFFSETS),
           CurStrSection);
       if (!EID)
-        return EID.takeError();
+        return createFileError(Input, EID.takeError());
       const auto &ID = *EID;
       if (!P.second)
         return buildDuplicateError(*P.first, ID, Input);