1 files changed, 37 insertions, 28 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 774f7d1df4e..5fc8d0622a4 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -568,25 +568,10 @@ void DwarfDebug::addGnuPubAttributes(DwarfCompileUnit &U, DIE &D) const {
   U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
 }
 
-// Create new DwarfCompileUnit for the given metadata node with tag
-// DW_TAG_compile_unit.
-DwarfCompileUnit &
-DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
-  if (auto *CU = CUMap.lookup(DIUnit))
-    return *CU;
-  StringRef FN = DIUnit->getFilename();
-  CompilationDir = DIUnit->getDirectory();
-
-  auto OwnedUnit = llvm::make_unique<DwarfCompileUnit>(
-      InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
-  DwarfCompileUnit &NewCU = *OwnedUnit;
+void DwarfDebug::finishUnitAttributes(const DICompileUnit *DIUnit,
+                                      DwarfCompileUnit &NewCU) {
   DIE &Die = NewCU.getUnitDie();
-  InfoHolder.addUnit(std::move(OwnedUnit));
-  if (useSplitDwarf()) {
-    NewCU.setSkeleton(constructSkeletonCU(NewCU));
-    NewCU.addString(Die, dwarf::DW_AT_GNU_dwo_name,
-                  Asm->TM.Options.MCOptions.SplitDwarfFile);
-  }
+  StringRef FN = DIUnit->getFilename();
 
   for (auto *IE : DIUnit->getImportedEntities())
     NewCU.addImportedEntity(IE);
@@ -640,11 +625,6 @@ DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
                     dwarf::DW_FORM_data1, RVer);
   }
 
-  if (useSplitDwarf())
-    NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
-  else
-    NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoSection());
-
   if (DIUnit->getDWOId()) {
     // This CU is either a clang module DWO or a skeleton CU.
     NewCU.addUInt(Die, dwarf::DW_AT_GNU_dwo_id, dwarf::DW_FORM_data8,
@@ -654,9 +634,31 @@ DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
       NewCU.addString(Die, dwarf::DW_AT_GNU_dwo_name,
                       DIUnit->getSplitDebugFilename());
   }
+}
+// Create new DwarfCompileUnit for the given metadata node with tag
+// DW_TAG_compile_unit.
+DwarfCompileUnit &
+DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
+  if (auto *CU = CUMap.lookup(DIUnit))
+    return *CU;
+
+  CompilationDir = DIUnit->getDirectory();
+
+  auto OwnedUnit = llvm::make_unique<DwarfCompileUnit>(
+      InfoHolder.getUnits().size(), DIUnit, Asm, this, &InfoHolder);
+  DwarfCompileUnit &NewCU = *OwnedUnit;
+  InfoHolder.addUnit(std::move(OwnedUnit));
+
+  if (useSplitDwarf()) {
+    NewCU.setSkeleton(constructSkeletonCU(NewCU));
+    NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoDWOSection());
+  } else {
+    finishUnitAttributes(DIUnit, NewCU);
+    NewCU.setSection(Asm->getObjFileLowering().getDwarfInfoSection());
+  }
 
   CUMap.insert({DIUnit, &NewCU});
-  CUDieMap.insert({&Die, &NewCU});
+  CUDieMap.insert({&NewCU.getUnitDie(), &NewCU});
   return NewCU;
 }
 
@@ -851,7 +853,12 @@ void DwarfDebug::finalizeModuleInfo() {
     // If we're splitting the dwarf out now that we've got the entire
     // CU then add the dwo id to it.
     auto *SkCU = TheCU.getSkeleton();
-    if (useSplitDwarf()) {
+    if (useSplitDwarf() && !empty(TheCU.getUnitDie().children())) {
+      finishUnitAttributes(TheCU.getCUNode(), TheCU);
+      TheCU.addString(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_name,
+                      Asm->TM.Options.MCOptions.SplitDwarfFile);
+      SkCU->addString(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_name,
+                      Asm->TM.Options.MCOptions.SplitDwarfFile);
       // Emit a unique identifier for this CU.
       uint64_t ID =
           DIEHash(Asm).computeCUSignature(DWOName, TheCU.getUnitDie());
@@ -870,6 +877,8 @@ void DwarfDebug::finalizeModuleInfo() {
         SkCU->addSectionLabel(SkCU->getUnitDie(), dwarf::DW_AT_GNU_ranges_base,
                               Sym, Sym);
       }
+    } else if (SkCU) {
+      finishUnitAttributes(SkCU->getCUNode(), *SkCU);
     }
 
     // If we have code split among multiple sections or non-contiguous
@@ -882,7 +891,9 @@ void DwarfDebug::finalizeModuleInfo() {
 
     // We don't keep track of which addresses are used in which CU so this
     // is a bit pessimistic under LTO.
-    if (!AddrPool.isEmpty())
+    if (!AddrPool.isEmpty() &&
+        (getDwarfVersion() >= 5 ||
+         (SkCU && !empty(TheCU.getUnitDie().children()))))
       U.addAddrTableBase();
 
     if (unsigned NumRanges = TheCU.getRanges().size()) {
@@ -2483,8 +2494,6 @@ void DwarfDebug::emitDebugMacinfo() {
 
 void DwarfDebug::initSkeletonUnit(const DwarfUnit &U, DIE &Die,
                                   std::unique_ptr<DwarfCompileUnit> NewU) {
-  NewU->addString(Die, dwarf::DW_AT_GNU_dwo_name,
-                  Asm->TM.Options.MCOptions.SplitDwarfFile);
 
   if (!CompilationDir.empty())
     NewU->addString(Die, dwarf::DW_AT_comp_dir, CompilationDir);