Don't warn about missing DWO files when converting mach-o files.

Apple uses the DW_AT_GNU_dwo_id for non split DWARF cases. Any compile units with this attribute would cause many warnings to be emitted:

"warning: Unable to retrieve DWO .debug_info section for"

This patch fixes the DWARFTransformer to not look for skeleton compile unit in mach-o based binaries and adds a unit test.

Author: clayborg

llvm/include/llvm/DebugInfo/GSYM/DwarfTransformer.h

@@ -43,8 +43,14 @@ class DwarfTransformer {
   ///
   /// \param LDCS Flag to indicate whether we should load the call site
   /// information from DWARF `DW_TAG_call_site` entries
-  DwarfTransformer(DWARFContext &D, GsymCreator &G, bool LDCS = false)
-      : DICtx(D), Gsym(G), LoadDwarfCallSites(LDCS) {}
+  ///
+  /// \param MachO Flag to indicate if the object file is mach-o (Apple's
+  /// executable format). Apple has some compile unit attributes that look like
+  /// split DWARF, but they aren't and they can cause warnins to be emitted
+  /// about missing DWO files.
+  DwarfTransformer(DWARFContext &D, GsymCreator &G, bool LDCS = false,
+                   bool MachO = false)
+      : DICtx(D), Gsym(G), LoadDwarfCallSites(LDCS), IsMachO(MachO) {}
 
   /// Extract the DWARF from the supplied object file and convert it into the
   /// Gsym format in the GsymCreator object that is passed in. Returns an
@@ -63,7 +69,6 @@ class DwarfTransformer {
   LLVM_ABI llvm::Error verify(StringRef GsymPath, OutputAggregator &OS);
 
 private:
-
   /// Parse the DWARF in the object file and convert it into the GsymCreator.
   Error parse();
 
@@ -97,6 +102,7 @@ class DwarfTransformer {
   DWARFContext &DICtx;
   GsymCreator &Gsym;
   bool LoadDwarfCallSites;
+  bool IsMachO;
 
   friend class DwarfTransformerTest;
 };

llvm/lib/DebugInfo/GSYM/DwarfTransformer.cpp

@@ -82,7 +82,6 @@ struct llvm::gsym::CUInfo {
   }
 };
 
-
 static DWARFDie GetParentDeclContextDIE(DWARFDie &Die) {
   if (DWARFDie SpecDie =
           Die.getAttributeValueAsReferencedDie(dwarf::DW_AT_specification)) {
@@ -170,7 +169,7 @@ getQualifiedNameIndex(DWARFDie &Die, uint64_t Language, GsymCreator &Gsym) {
         // templates
         if (ParentName.front() == '<' && ParentName.back() == '>')
           Name = "{" + ParentName.substr(1, ParentName.size() - 2).str() + "}" +
-                "::" + Name;
+                 "::" + Name;
         else
           Name = ParentName.str() + "::" + Name;
       }
@@ -432,7 +431,7 @@ static void convertFunctionLineTable(OutputAggregator &Out, CUInfo &CUI,
     // Skip multiple line entries for the same file and line.
     auto LastLE = FI.OptLineTable->last();
     if (LastLE && LastLE->File == FileIdx && LastLE->Line == Row.Line)
-        continue;
+      continue;
     // Only push a row if it isn't an end sequence. End sequence markers are
     // included for the last address in a function or the last contiguous
     // address in a sequence.
@@ -629,6 +628,10 @@ Error DwarfTransformer::convert(uint32_t NumThreads, OutputAggregator &Out) {
   size_t NumBefore = Gsym.getNumFunctionInfos();
   auto getDie = [&](DWARFUnit &DwarfUnit) -> DWARFDie {
     DWARFDie ReturnDie = DwarfUnit.getUnitDIE(false);
+    // Apple uses DW_AT_GNU_dwo_id for things other than split DWARF.
+    if (IsMachO)
+      return ReturnDie;
+
     if (DwarfUnit.getDWOId()) {
       DWARFUnit *DWOCU = DwarfUnit.getNonSkeletonUnitDIE(false).getDwarfUnit();
       if (!DWOCU->isDWOUnit())
@@ -718,8 +721,8 @@ llvm::Error DwarfTransformer::verify(StringRef GsymPath,
   for (uint32_t I = 0; I < NumAddrs; ++I) {
     auto FuncAddr = Gsym->getAddress(I);
     if (!FuncAddr)
-        return createStringError(std::errc::invalid_argument,
-                                  "failed to extract address[%i]", I);
+      return createStringError(std::errc::invalid_argument,
+                               "failed to extract address[%i]", I);
 
     auto FI = Gsym->getFunctionInfo(*FuncAddr);
     if (!FI)
@@ -734,8 +737,7 @@ llvm::Error DwarfTransformer::verify(StringRef GsymPath,
       if (!LR)
         return LR.takeError();
 
-      auto DwarfInlineInfos =
-          DICtx.getInliningInfoForAddress(SectAddr, DLIS);
+      auto DwarfInlineInfos = DICtx.getInliningInfoForAddress(SectAddr, DLIS);
       uint32_t NumDwarfInlineInfos = DwarfInlineInfos.getNumberOfFrames();
       if (NumDwarfInlineInfos == 0) {
         DwarfInlineInfos.addFrame(
@@ -773,8 +775,7 @@ llvm::Error DwarfTransformer::verify(StringRef GsymPath,
         continue;
       }
 
-      for (size_t Idx = 0, count = LR->Locations.size(); Idx < count;
-            ++Idx) {
+      for (size_t Idx = 0, count = LR->Locations.size(); Idx < count; ++Idx) {
         const auto &gii = LR->Locations[Idx];
         if (Idx < NumDwarfInlineInfos) {
           const auto &dii = DwarfInlineInfos.getFrame(Idx);

llvm/tools/llvm-gsymutil/llvm-gsymutil.cpp

@@ -374,19 +374,20 @@ static llvm::Error handleObjectFile(ObjectFile &Obj, const std::string &OutFile,
   // Make sure there is DWARF to convert first.
   std::unique_ptr<DWARFContext> DICtx = DWARFContext::create(
       Obj,
-      /*RelocAction=*/DWARFContext::ProcessDebugRelocations::Process,
-      nullptr,
+      /*RelocAction=*/DWARFContext::ProcessDebugRelocations::Process, nullptr,
       /*DWPName=*/"",
       /*RecoverableErrorHandler=*/WithColor::defaultErrorHandler,
       /*WarningHandler=*/WithColor::defaultWarningHandler,
-      /*ThreadSafe*/true);
+      /*ThreadSafe*/ true);
   if (!DICtx)
     return createStringError(std::errc::invalid_argument,
                              "unable to create DWARF context");
 
   // Make a DWARF transformer object and populate the ranges of the code
   // so we don't end up adding invalid functions to GSYM data.
-  DwarfTransformer DT(*DICtx, Gsym, LoadDwarfCallSites);
+  bool IsMachO = dyn_cast<object::MachOObjectFile>(&Obj) != nullptr;
+
+  DwarfTransformer DT(*DICtx, Gsym, LoadDwarfCallSites, IsMachO);
   if (!TextRanges.empty())
     Gsym.SetValidTextRanges(TextRanges);