4 files changed, 14 insertions, 18 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index b392586ef10..024472db87c 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2122,11 +2122,9 @@ void DwarfDebug::emitDebugAbbrevDWO() {
 
 void DwarfDebug::emitDebugLineDWO() {
   assert(useSplitDwarf() && "No split dwarf?");
-  if (!HasSplitTypeUnits)
-    return;
-  Asm->OutStreamer->SwitchSection(
+  SplitTypeUnitFileTable.Emit(
+      *Asm->OutStreamer, MCDwarfLineTableParams(),
       Asm->getObjFileLowering().getDwarfLineDWOSection());
-  SplitTypeUnitFileTable.Emit(*Asm->OutStreamer, MCDwarfLineTableParams());
 }
 
 void DwarfDebug::emitStringOffsetsTableHeaderDWO() {
@@ -2200,8 +2198,9 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
   if (useSplitDwarf())
     NewTU.setSection(Asm->getObjFileLowering().getDwarfTypesDWOSection());
   else {
-    CU.applyStmtList(UnitDie);
     NewTU.setSection(Asm->getObjFileLowering().getDwarfTypesSection(Signature));
+    // Non-split type units reuse the compile unit's line table.
+    CU.applyStmtList(UnitDie);
   }
 
   // Add DW_AT_str_offsets_base to the type unit DIE, but not for split type
@@ -2239,7 +2238,6 @@ void DwarfDebug::addDwarfTypeUnitType(DwarfCompileUnit &CU,
       InfoHolder.computeSizeAndOffsetsForUnit(TU.first.get());
       InfoHolder.emitUnit(TU.first.get(), useSplitDwarf());
     }
-    HasSplitTypeUnits = useSplitDwarf();
   }
   CU.addDIETypeSignature(RefDie, Signature);
 }
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 52b920682ce..3ee78710e8f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -280,10 +280,6 @@ class DwarfDebug : public DebugHandlerBase {
   /// a monolithic sequence of string offsets.
   bool UseSegmentedStringOffsetsTable;
 
-  /// Whether we have emitted any type units with split DWARF (and therefore
-  /// need to emit a line table to the .dwo file).
-  bool HasSplitTypeUnits = false;
-
   /// Separated Dwarf Variables
   /// In general these will all be for bits that are left in the
   /// original object file, rather than things that are meant
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 16ce3d7791c..811112a0430 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -85,8 +85,6 @@ DwarfTypeUnit::DwarfTypeUnit(DwarfCompileUnit &CU, AsmPrinter *A,
                              MCDwarfDwoLineTable *SplitLineTable)
     : DwarfUnit(dwarf::DW_TAG_type_unit, CU.getCUNode(), A, DW, DWU), CU(CU),
       SplitLineTable(SplitLineTable) {
-  if (SplitLineTable)
-    addSectionOffset(getUnitDie(), dwarf::DW_AT_stmt_list, 0);
 }
 
 DwarfUnit::~DwarfUnit() {
@@ -300,12 +298,15 @@ MD5::MD5Result *DwarfUnit::getMD5AsBytes(const DIFile *File) {
 }
 
 unsigned DwarfTypeUnit::getOrCreateSourceID(const DIFile *File) {
-  return SplitLineTable
-             ? SplitLineTable->getFile(File->getDirectory(),
-                                       File->getFilename(),
-                                       getMD5AsBytes(File),
-                                       File->getSource())
-             : getCU().getOrCreateSourceID(File);
+  if (!SplitLineTable)
+    return getCU().getOrCreateSourceID(File);
+  if (!UsedLineTable) {
+    UsedLineTable = true;
+    // This is a split type unit that needs a line table.
+    addSectionOffset(getUnitDie(), dwarf::DW_AT_stmt_list, 0);
+  }
+  return SplitLineTable->getFile(File->getDirectory(), File->getFilename(),
+                                 getMD5AsBytes(File), File->getSource());
 }
 
 void DwarfUnit::addOpAddress(DIELoc &Die, const MCSymbol *Sym) {
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
index 5de39637f52..328e3549e05 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h
@@ -367,6 +367,7 @@ class DwarfTypeUnit final : public DwarfUnit {
   const DIE *Ty;
   DwarfCompileUnit &CU;
   MCDwarfDwoLineTable *SplitLineTable;
+  bool UsedLineTable = false;
 
   unsigned getOrCreateSourceID(const DIFile *File) override;
   bool isDwoUnit() const override;