10 files changed, 174 insertions, 229 deletions

diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 7ddb86d80bf07..d72cf59229874 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -628,12 +628,15 @@ void AsmPrinter::EmitDebugThreadLocal(const MCExpr *Value,
 /// EmitFunctionHeader - This method emits the header for the current
 /// function.
 void AsmPrinter::EmitFunctionHeader() {
+  const Function *F = MF->getFunction();
+
+  if (isVerbose())
+    OutStreamer->GetCommentOS() << "-- Begin function " << F->getName() << '\n';
+
   // Print out constants referenced by the function
   EmitConstantPool();
 
   // Print the 'header' of function.
-  const Function *F = MF->getFunction();
-
   OutStreamer->SwitchSection(getObjFileLowering().SectionForGlobal(F, TM));
   EmitVisibility(CurrentFnSym, F->getVisibility());
 
@@ -1107,6 +1110,9 @@ void AsmPrinter::EmitFunctionBody() {
     HI.Handler->endFunction(MF);
   }
 
+  if (isVerbose())
+    OutStreamer->GetCommentOS() << "-- End function\n";
+
   OutStreamer->AddBlankLine();
 }
 
diff --git a/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 1b39e46ee4667..114aea391a86e 100644
--- a/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1025,11 +1025,11 @@ void CodeViewDebug::beginFunctionImpl(const MachineFunction *MF) {
   bool EmptyPrologue = true;
   for (const auto &MBB : *MF) {
     for (const auto &MI : MBB) {
-      if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
+      if (!MI.isMetaInstruction() && !MI.getFlag(MachineInstr::FrameSetup) &&
           MI.getDebugLoc()) {
         PrologEndLoc = MI.getDebugLoc();
         break;
-      } else if (!MI.isDebugValue()) {
+      } else if (!MI.isMetaInstruction()) {
         EmptyPrologue = false;
       }
     }
@@ -1562,7 +1562,7 @@ TypeIndex CodeViewDebug::lowerTypeEnum(const DICompositeType *Ty) {
         EnumeratorCount++;
       }
     }
-    FTI = FLRB.end();
+    FTI = FLRB.end(true);
   }
 
   std::string FullName = getFullyQualifiedName(Ty);
@@ -1869,7 +1869,7 @@ CodeViewDebug::lowerRecordFieldList(const DICompositeType *Ty) {
     MemberCount++;
   }
 
-  TypeIndex FieldTI = FLBR.end();
+  TypeIndex FieldTI = FLBR.end(true);
   return std::make_tuple(FieldTI, Info.VShapeTI, MemberCount,
                          !Info.NestedClasses.empty());
 }
diff --git a/lib/CodeGen/AsmPrinter/DIEHash.cpp b/lib/CodeGen/AsmPrinter/DIEHash.cpp
index 8e3b88d0af0e5..201030f0ac5cc 100644
--- a/lib/CodeGen/AsmPrinter/DIEHash.cpp
+++ b/lib/CodeGen/AsmPrinter/DIEHash.cpp
@@ -116,65 +116,17 @@ void DIEHash::addParentContext(const DIE &Parent) {
 
 // Collect all of the attributes for a particular DIE in single structure.
 void DIEHash::collectAttributes(const DIE &Die, DIEAttrs &Attrs) {
-#define COLLECT_ATTR(NAME)                                                     \
-  case dwarf::NAME:                                                            \
-    Attrs.NAME = V;                                                            \
-    break
 
   for (const auto &V : Die.values()) {
     DEBUG(dbgs() << "Attribute: "
                  << dwarf::AttributeString(V.getAttribute())
                  << " added.\n");
     switch (V.getAttribute()) {
-      COLLECT_ATTR(DW_AT_name);
-      COLLECT_ATTR(DW_AT_accessibility);
-      COLLECT_ATTR(DW_AT_address_class);
-      COLLECT_ATTR(DW_AT_allocated);
-      COLLECT_ATTR(DW_AT_artificial);
-      COLLECT_ATTR(DW_AT_associated);
-      COLLECT_ATTR(DW_AT_binary_scale);
-      COLLECT_ATTR(DW_AT_bit_offset);
-      COLLECT_ATTR(DW_AT_bit_size);
-      COLLECT_ATTR(DW_AT_bit_stride);
-      COLLECT_ATTR(DW_AT_byte_size);
-      COLLECT_ATTR(DW_AT_byte_stride);
-      COLLECT_ATTR(DW_AT_const_expr);
-      COLLECT_ATTR(DW_AT_const_value);
-      COLLECT_ATTR(DW_AT_containing_type);
-      COLLECT_ATTR(DW_AT_count);
-      COLLECT_ATTR(DW_AT_data_bit_offset);
-      COLLECT_ATTR(DW_AT_data_location);
-      COLLECT_ATTR(DW_AT_data_member_location);
-      COLLECT_ATTR(DW_AT_decimal_scale);
-      COLLECT_ATTR(DW_AT_decimal_sign);
-      COLLECT_ATTR(DW_AT_default_value);
-      COLLECT_ATTR(DW_AT_digit_count);
-      COLLECT_ATTR(DW_AT_discr);
-      COLLECT_ATTR(DW_AT_discr_list);
-      COLLECT_ATTR(DW_AT_discr_value);
-      COLLECT_ATTR(DW_AT_encoding);
-      COLLECT_ATTR(DW_AT_enum_class);
-      COLLECT_ATTR(DW_AT_endianity);
-      COLLECT_ATTR(DW_AT_explicit);
-      COLLECT_ATTR(DW_AT_is_optional);
-      COLLECT_ATTR(DW_AT_location);
-      COLLECT_ATTR(DW_AT_lower_bound);
-      COLLECT_ATTR(DW_AT_mutable);
-      COLLECT_ATTR(DW_AT_ordering);
-      COLLECT_ATTR(DW_AT_picture_string);
-      COLLECT_ATTR(DW_AT_prototyped);
-      COLLECT_ATTR(DW_AT_small);
-      COLLECT_ATTR(DW_AT_segment);
-      COLLECT_ATTR(DW_AT_string_length);
-      COLLECT_ATTR(DW_AT_threads_scaled);
-      COLLECT_ATTR(DW_AT_upper_bound);
-      COLLECT_ATTR(DW_AT_use_location);
-      COLLECT_ATTR(DW_AT_use_UTF8);
-      COLLECT_ATTR(DW_AT_variable_parameter);
-      COLLECT_ATTR(DW_AT_virtuality);
-      COLLECT_ATTR(DW_AT_visibility);
-      COLLECT_ATTR(DW_AT_vtable_elem_location);
-      COLLECT_ATTR(DW_AT_type);
+#define HANDLE_DIE_HASH_ATTR(NAME)                                             \
+  case dwarf::NAME:                                                            \
+    Attrs.NAME = V;                                                            \
+    break;
+#include "DIEHashAttributes.def"
     default:
       break;
     }
@@ -366,62 +318,12 @@ void DIEHash::hashAttribute(const DIEValue &Value, dwarf::Tag Tag) {
 // Go through the attributes from \param Attrs in the order specified in 7.27.4
 // and hash them.
 void DIEHash::hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag) {
-#define ADD_ATTR(ATTR)                                                         \
+#define HANDLE_DIE_HASH_ATTR(NAME)                                             \
   {                                                                            \
-    if (ATTR)                                                                  \
-      hashAttribute(ATTR, Tag);                                                \
+    if (Attrs.NAME)                                                           \
+      hashAttribute(Attrs.NAME, Tag);                                         \
   }
-
-  ADD_ATTR(Attrs.DW_AT_name);
-  ADD_ATTR(Attrs.DW_AT_accessibility);
-  ADD_ATTR(Attrs.DW_AT_address_class);
-  ADD_ATTR(Attrs.DW_AT_allocated);
-  ADD_ATTR(Attrs.DW_AT_artificial);
-  ADD_ATTR(Attrs.DW_AT_associated);
-  ADD_ATTR(Attrs.DW_AT_binary_scale);
-  ADD_ATTR(Attrs.DW_AT_bit_offset);
-  ADD_ATTR(Attrs.DW_AT_bit_size);
-  ADD_ATTR(Attrs.DW_AT_bit_stride);
-  ADD_ATTR(Attrs.DW_AT_byte_size);
-  ADD_ATTR(Attrs.DW_AT_byte_stride);
-  ADD_ATTR(Attrs.DW_AT_const_expr);
-  ADD_ATTR(Attrs.DW_AT_const_value);
-  ADD_ATTR(Attrs.DW_AT_containing_type);
-  ADD_ATTR(Attrs.DW_AT_count);
-  ADD_ATTR(Attrs.DW_AT_data_bit_offset);
-  ADD_ATTR(Attrs.DW_AT_data_location);
-  ADD_ATTR(Attrs.DW_AT_data_member_location);
-  ADD_ATTR(Attrs.DW_AT_decimal_scale);
-  ADD_ATTR(Attrs.DW_AT_decimal_sign);
-  ADD_ATTR(Attrs.DW_AT_default_value);
-  ADD_ATTR(Attrs.DW_AT_digit_count);
-  ADD_ATTR(Attrs.DW_AT_discr);
-  ADD_ATTR(Attrs.DW_AT_discr_list);
-  ADD_ATTR(Attrs.DW_AT_discr_value);
-  ADD_ATTR(Attrs.DW_AT_encoding);
-  ADD_ATTR(Attrs.DW_AT_enum_class);
-  ADD_ATTR(Attrs.DW_AT_endianity);
-  ADD_ATTR(Attrs.DW_AT_explicit);
-  ADD_ATTR(Attrs.DW_AT_is_optional);
-  ADD_ATTR(Attrs.DW_AT_location);
-  ADD_ATTR(Attrs.DW_AT_lower_bound);
-  ADD_ATTR(Attrs.DW_AT_mutable);
-  ADD_ATTR(Attrs.DW_AT_ordering);
-  ADD_ATTR(Attrs.DW_AT_picture_string);
-  ADD_ATTR(Attrs.DW_AT_prototyped);
-  ADD_ATTR(Attrs.DW_AT_small);
-  ADD_ATTR(Attrs.DW_AT_segment);
-  ADD_ATTR(Attrs.DW_AT_string_length);
-  ADD_ATTR(Attrs.DW_AT_threads_scaled);
-  ADD_ATTR(Attrs.DW_AT_upper_bound);
-  ADD_ATTR(Attrs.DW_AT_use_location);
-  ADD_ATTR(Attrs.DW_AT_use_UTF8);
-  ADD_ATTR(Attrs.DW_AT_variable_parameter);
-  ADD_ATTR(Attrs.DW_AT_virtuality);
-  ADD_ATTR(Attrs.DW_AT_visibility);
-  ADD_ATTR(Attrs.DW_AT_vtable_elem_location);
-  ADD_ATTR(Attrs.DW_AT_type);
-
+#include "DIEHashAttributes.def"
   // FIXME: Add the extended attributes.
 }
 
@@ -478,10 +380,12 @@ void DIEHash::computeHash(const DIE &Die) {
 /// DWARF4 standard. It is an md5 hash of the flattened description of the DIE
 /// with the inclusion of the full CU and all top level CU entities.
 // TODO: Initialize the type chain at 0 instead of 1 for CU signatures.
-uint64_t DIEHash::computeCUSignature(const DIE &Die) {
+uint64_t DIEHash::computeCUSignature(StringRef DWOName, const DIE &Die) {
   Numbering.clear();
   Numbering[&Die] = 1;
 
+  if (!DWOName.empty())
+    Hash.update(DWOName);
   // Hash the DIE.
   computeHash(Die);
 
diff --git a/lib/CodeGen/AsmPrinter/DIEHash.h b/lib/CodeGen/AsmPrinter/DIEHash.h
index 996cd7ef3d2e5..29337ae38a996 100644
--- a/lib/CodeGen/AsmPrinter/DIEHash.h
+++ b/lib/CodeGen/AsmPrinter/DIEHash.h
@@ -28,64 +28,15 @@ class CompileUnit;
 class DIEHash {
   // Collection of all attributes used in hashing a particular DIE.
   struct DIEAttrs {
-    DIEValue DW_AT_name;
-    DIEValue DW_AT_accessibility;
-    DIEValue DW_AT_address_class;
-    DIEValue DW_AT_allocated;
-    DIEValue DW_AT_artificial;
-    DIEValue DW_AT_associated;
-    DIEValue DW_AT_binary_scale;
-    DIEValue DW_AT_bit_offset;
-    DIEValue DW_AT_bit_size;
-    DIEValue DW_AT_bit_stride;
-    DIEValue DW_AT_byte_size;
-    DIEValue DW_AT_byte_stride;
-    DIEValue DW_AT_const_expr;
-    DIEValue DW_AT_const_value;
-    DIEValue DW_AT_containing_type;
-    DIEValue DW_AT_count;
-    DIEValue DW_AT_data_bit_offset;
-    DIEValue DW_AT_data_location;
-    DIEValue DW_AT_data_member_location;
-    DIEValue DW_AT_decimal_scale;
-    DIEValue DW_AT_decimal_sign;
-    DIEValue DW_AT_default_value;
-    DIEValue DW_AT_digit_count;
-    DIEValue DW_AT_discr;
-    DIEValue DW_AT_discr_list;
-    DIEValue DW_AT_discr_value;
-    DIEValue DW_AT_encoding;
-    DIEValue DW_AT_enum_class;
-    DIEValue DW_AT_endianity;
-    DIEValue DW_AT_explicit;
-    DIEValue DW_AT_is_optional;
-    DIEValue DW_AT_location;
-    DIEValue DW_AT_lower_bound;
-    DIEValue DW_AT_mutable;
-    DIEValue DW_AT_ordering;
-    DIEValue DW_AT_picture_string;
-    DIEValue DW_AT_prototyped;
-    DIEValue DW_AT_small;
-    DIEValue DW_AT_segment;
-    DIEValue DW_AT_string_length;
-    DIEValue DW_AT_threads_scaled;
-    DIEValue DW_AT_upper_bound;
-    DIEValue DW_AT_use_location;
-    DIEValue DW_AT_use_UTF8;
-    DIEValue DW_AT_variable_parameter;
-    DIEValue DW_AT_virtuality;
-    DIEValue DW_AT_visibility;
-    DIEValue DW_AT_vtable_elem_location;
-    DIEValue DW_AT_type;
-
-    // Insert any additional ones here...
+#define HANDLE_DIE_HASH_ATTR(NAME) DIEValue NAME;
+#include "DIEHashAttributes.def"
   };
 
 public:
   DIEHash(AsmPrinter *A = nullptr) : AP(A) {}
 
   /// \brief Computes the CU signature.
-  uint64_t computeCUSignature(const DIE &Die);
+  uint64_t computeCUSignature(StringRef DWOName, const DIE &Die);
 
   /// \brief Computes the type signature.
   uint64_t computeTypeSignature(const DIE &Die);
diff --git a/lib/CodeGen/AsmPrinter/DIEHashAttributes.def b/lib/CodeGen/AsmPrinter/DIEHashAttributes.def
new file mode 100644
index 0000000000000..28a02390fccb6
--- /dev/null
+++ b/lib/CodeGen/AsmPrinter/DIEHashAttributes.def
@@ -0,0 +1,55 @@
+#ifndef HANDLE_DIE_HASH_ATTR
+#error "Missing macro definition of HANDLE_DIE_HASH_ATTR"
+#endif
+
+HANDLE_DIE_HASH_ATTR(DW_AT_name)
+HANDLE_DIE_HASH_ATTR(DW_AT_accessibility)
+HANDLE_DIE_HASH_ATTR(DW_AT_address_class)
+HANDLE_DIE_HASH_ATTR(DW_AT_allocated)
+HANDLE_DIE_HASH_ATTR(DW_AT_artificial)
+HANDLE_DIE_HASH_ATTR(DW_AT_associated)
+HANDLE_DIE_HASH_ATTR(DW_AT_binary_scale)
+HANDLE_DIE_HASH_ATTR(DW_AT_bit_offset)
+HANDLE_DIE_HASH_ATTR(DW_AT_bit_size)
+HANDLE_DIE_HASH_ATTR(DW_AT_bit_stride)
+HANDLE_DIE_HASH_ATTR(DW_AT_byte_size)
+HANDLE_DIE_HASH_ATTR(DW_AT_byte_stride)
+HANDLE_DIE_HASH_ATTR(DW_AT_const_expr)
+HANDLE_DIE_HASH_ATTR(DW_AT_const_value)
+HANDLE_DIE_HASH_ATTR(DW_AT_containing_type)
+HANDLE_DIE_HASH_ATTR(DW_AT_count)
+HANDLE_DIE_HASH_ATTR(DW_AT_data_bit_offset)
+HANDLE_DIE_HASH_ATTR(DW_AT_data_location)
+HANDLE_DIE_HASH_ATTR(DW_AT_data_member_location)
+HANDLE_DIE_HASH_ATTR(DW_AT_decimal_scale)
+HANDLE_DIE_HASH_ATTR(DW_AT_decimal_sign)
+HANDLE_DIE_HASH_ATTR(DW_AT_default_value)
+HANDLE_DIE_HASH_ATTR(DW_AT_digit_count)
+HANDLE_DIE_HASH_ATTR(DW_AT_discr)
+HANDLE_DIE_HASH_ATTR(DW_AT_discr_list)
+HANDLE_DIE_HASH_ATTR(DW_AT_discr_value)
+HANDLE_DIE_HASH_ATTR(DW_AT_encoding)
+HANDLE_DIE_HASH_ATTR(DW_AT_enum_class)
+HANDLE_DIE_HASH_ATTR(DW_AT_endianity)
+HANDLE_DIE_HASH_ATTR(DW_AT_explicit)
+HANDLE_DIE_HASH_ATTR(DW_AT_is_optional)
+HANDLE_DIE_HASH_ATTR(DW_AT_location)
+HANDLE_DIE_HASH_ATTR(DW_AT_lower_bound)
+HANDLE_DIE_HASH_ATTR(DW_AT_mutable)
+HANDLE_DIE_HASH_ATTR(DW_AT_ordering)
+HANDLE_DIE_HASH_ATTR(DW_AT_picture_string)
+HANDLE_DIE_HASH_ATTR(DW_AT_prototyped)
+HANDLE_DIE_HASH_ATTR(DW_AT_small)
+HANDLE_DIE_HASH_ATTR(DW_AT_segment)
+HANDLE_DIE_HASH_ATTR(DW_AT_string_length)
+HANDLE_DIE_HASH_ATTR(DW_AT_threads_scaled)
+HANDLE_DIE_HASH_ATTR(DW_AT_upper_bound)
+HANDLE_DIE_HASH_ATTR(DW_AT_use_location)
+HANDLE_DIE_HASH_ATTR(DW_AT_use_UTF8)
+HANDLE_DIE_HASH_ATTR(DW_AT_variable_parameter)
+HANDLE_DIE_HASH_ATTR(DW_AT_virtuality)
+HANDLE_DIE_HASH_ATTR(DW_AT_visibility)
+HANDLE_DIE_HASH_ATTR(DW_AT_vtable_elem_location)
+HANDLE_DIE_HASH_ATTR(DW_AT_type)
+
+#undef HANDLE_DIE_HASH_ATTR
diff --git a/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
index 826162ad47c45..0971c5942203c 100644
--- a/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
+++ b/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -115,7 +115,8 @@ uint64_t DebugHandlerBase::getBaseTypeSize(const DITypeRef TyRef) {
   return getBaseTypeSize(BaseType);
 }
 
-bool hasDebugInfo(const MachineModuleInfo *MMI, const MachineFunction *MF) {
+static bool hasDebugInfo(const MachineModuleInfo *MMI,
+                         const MachineFunction *MF) {
   if (!MMI->hasDebugInfo())
     return false;
   auto *SP = MF->getFunction()->getSubprogram();
@@ -223,9 +224,9 @@ void DebugHandlerBase::endInstruction() {
     return;
 
   assert(CurMI != nullptr);
-  // Don't create a new label after DBG_VALUE instructions.
-  // They don't generate code.
-  if (!CurMI->isDebugValue()) {
+  // Don't create a new label after DBG_VALUE and other instructions that don't
+  // generate code.
+  if (!CurMI->isMetaInstruction()) {
     PrevLabel = nullptr;
     PrevInstBB = CurMI->getParent();
   }
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index e172712cf8894..04073b3aed684 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -760,7 +760,7 @@ void DwarfCompileUnit::emitHeader(bool UseOffsets) {
 /// addGlobalName - Add a new global name to the compile unit.
 void DwarfCompileUnit::addGlobalName(StringRef Name, const DIE &Die,
                                      const DIScope *Context) {
-  if (includeMinimalInlineScopes())
+  if (!DD->hasDwarfPubSections(includeMinimalInlineScopes()))
     return;
   std::string FullName = getParentContextString(Context) + Name.str();
   GlobalNames[FullName] = &Die;
@@ -768,7 +768,7 @@ void DwarfCompileUnit::addGlobalName(StringRef Name, const DIE &Die,
 
 void DwarfCompileUnit::addGlobalNameForTypeUnit(StringRef Name,
                                                 const DIScope *Context) {
-  if (includeMinimalInlineScopes())
+  if (!DD->hasDwarfPubSections(includeMinimalInlineScopes()))
     return;
   std::string FullName = getParentContextString(Context) + Name.str();
   // Insert, allowing the entry to remain as-is if it's already present
@@ -781,7 +781,7 @@ void DwarfCompileUnit::addGlobalNameForTypeUnit(StringRef Name,
 /// Add a new global type to the unit.
 void DwarfCompileUnit::addGlobalType(const DIType *Ty, const DIE &Die,
                                      const DIScope *Context) {
-  if (includeMinimalInlineScopes())
+  if (!DD->hasDwarfPubSections(includeMinimalInlineScopes()))
     return;
   std::string FullName = getParentContextString(Context) + Ty->getName().str();
   GlobalTypes[FullName] = &Die;
@@ -789,7 +789,7 @@ void DwarfCompileUnit::addGlobalType(const DIType *Ty, const DIE &Die,
 
 void DwarfCompileUnit::addGlobalTypeUnitType(const DIType *Ty,
                                              const DIScope *Context) {
-  if (includeMinimalInlineScopes())
+  if (!DD->hasDwarfPubSections(includeMinimalInlineScopes()))
     return;
   std::string FullName = getParentContextString(Context) + Ty->getName().str();
   // Insert, allowing the entry to remain as-is if it's already present
diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 77e9e671529f5..b8f57472f17c4 100644
--- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -77,8 +77,6 @@ class DwarfCompileUnit final : public DwarfUnit {
 
   bool isDwoUnit() const override;
 
-  bool includeMinimalInlineScopes() const;
-
   DenseMap<const MDNode *, DIE *> &getAbstractSPDies() {
     if (isDwoUnit() && !DD->shareAcrossDWOCUs())
       return AbstractSPDies;
@@ -101,6 +99,8 @@ public:
     return Skeleton;
   }
 
+  bool includeMinimalInlineScopes() const;
+
   void initStmtList();
 
   /// Apply the DW_AT_stmt_list from this compile unit to the specified DIE.
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 3410b98d77766..bf27516e1ccd0 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -252,12 +252,6 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   // Handle split DWARF.
   HasSplitDwarf = !Asm->TM.Options.MCOptions.SplitDwarfFile.empty();
 
-  // Pubnames/pubtypes on by default for GDB.
-  if (DwarfPubSections == Default)
-    HasDwarfPubSections = tuneForGDB();
-  else
-    HasDwarfPubSections = DwarfPubSections == Enable;
-
   // SCE defaults to linkage names only for abstract subprograms.
   if (DwarfLinkageNames == DefaultLinkageNames)
     UseAllLinkageNames = !tuneForSCE();
@@ -380,19 +374,35 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU,
 
   // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
   // was inlined from another compile unit.
-  auto &CU = *CUMap.lookup(SP->getUnit());
-  if (auto *SkelCU = CU.getSkeleton()) {
-    (shareAcrossDWOCUs() ? CU : SrcCU)
-        .constructAbstractSubprogramScopeDIE(Scope);
-    if (CU.getCUNode()->getSplitDebugInlining())
-      SkelCU->constructAbstractSubprogramScopeDIE(Scope);
-  } else {
-    CU.constructAbstractSubprogramScopeDIE(Scope);
+  if (useSplitDwarf() && !shareAcrossDWOCUs() && !SP->getUnit()->getSplitDebugInlining())
+    // Avoid building the original CU if it won't be used
+    SrcCU.constructAbstractSubprogramScopeDIE(Scope);
+  else {
+    auto &CU = getOrCreateDwarfCompileUnit(SP->getUnit());
+    if (auto *SkelCU = CU.getSkeleton()) {
+      (shareAcrossDWOCUs() ? CU : SrcCU)
+          .constructAbstractSubprogramScopeDIE(Scope);
+      if (CU.getCUNode()->getSplitDebugInlining())
+        SkelCU->constructAbstractSubprogramScopeDIE(Scope);
+    } else
+      CU.constructAbstractSubprogramScopeDIE(Scope);
   }
 }
 
-void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
-  if (!GenerateGnuPubSections)
+bool DwarfDebug::hasDwarfPubSections(bool includeMinimalInlineScopes) const {
+  // Opting in to GNU Pubnames/types overrides the default to ensure these are
+  // generated for things like Gold's gdb_index generation.
+  if (GenerateGnuPubSections)
+    return true;
+
+  if (DwarfPubSections == Default)
+    return tuneForGDB() && !includeMinimalInlineScopes;
+
+  return DwarfPubSections == Enable;
+}
+
+void DwarfDebug::addGnuPubAttributes(DwarfCompileUnit &U, DIE &D) const {
+  if (!hasDwarfPubSections(U.includeMinimalInlineScopes()))
     return;
 
   U.addFlag(D, dwarf::DW_AT_GNU_pubnames);
@@ -401,7 +411,9 @@ void DwarfDebug::addGnuPubAttributes(DwarfUnit &U, DIE &D) const {
 // Create new DwarfCompileUnit for the given metadata node with tag
 // DW_TAG_compile_unit.
 DwarfCompileUnit &
-DwarfDebug::constructDwarfCompileUnit(const DICompileUnit *DIUnit) {
+DwarfDebug::getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit) {
+  if (auto *CU = CUMap.lookup(DIUnit))
+    return *CU;
   StringRef FN = DIUnit->getFilename();
   CompilationDir = DIUnit->getDirectory();
 
@@ -534,7 +546,12 @@ void DwarfDebug::beginModule() {
   }
 
   for (DICompileUnit *CUNode : M->debug_compile_units()) {
-    DwarfCompileUnit &CU = constructDwarfCompileUnit(CUNode);
+    if (CUNode->getEnumTypes().empty() && CUNode->getRetainedTypes().empty() &&
+        CUNode->getGlobalVariables().empty() &&
+        CUNode->getImportedEntities().empty() && CUNode->getMacros().empty())
+      continue;
+
+    DwarfCompileUnit &CU = getOrCreateDwarfCompileUnit(CUNode);
     for (auto *IE : CUNode->getImportedEntities())
       CU.addImportedEntity(IE);
 
@@ -581,11 +598,12 @@ void DwarfDebug::finishVariableDefinitions() {
 }
 
 void DwarfDebug::finishSubprogramDefinitions() {
-  for (const DISubprogram *SP : ProcessedSPNodes)
-    if (SP->getUnit()->getEmissionKind() != DICompileUnit::NoDebug)
-      forBothCUs(*CUMap.lookup(SP->getUnit()), [&](DwarfCompileUnit &CU) {
-        CU.finishSubprogramDefinition(SP);
-      });
+  for (const DISubprogram *SP : ProcessedSPNodes) {
+    assert(SP->getUnit()->getEmissionKind() != DICompileUnit::NoDebug);
+    forBothCUs(
+        getOrCreateDwarfCompileUnit(SP->getUnit()),
+        [&](DwarfCompileUnit &CU) { CU.finishSubprogramDefinition(SP); });
+  }
 }
 
 void DwarfDebug::finalizeModuleInfo() {
@@ -595,6 +613,13 @@ void DwarfDebug::finalizeModuleInfo() {
 
   finishVariableDefinitions();
 
+  // Include the DWO file name in the hash if there's more than one CU.
+  // This handles ThinLTO's situation where imported CUs may very easily be
+  // duplicate with the same CU partially imported into another ThinLTO unit.
+  StringRef DWOName;
+  if (CUMap.size() > 1)
+    DWOName = Asm->TM.Options.MCOptions.SplitDwarfFile;
+
   // Handle anything that needs to be done on a per-unit basis after
   // all other generation.
   for (const auto &P : CUMap) {
@@ -609,7 +634,8 @@ void DwarfDebug::finalizeModuleInfo() {
     auto *SkCU = TheCU.getSkeleton();
     if (useSplitDwarf()) {
       // Emit a unique identifier for this CU.
-      uint64_t ID = DIEHash(Asm).computeCUSignature(TheCU.getUnitDie());
+      uint64_t ID =
+          DIEHash(Asm).computeCUSignature(DWOName, TheCU.getUnitDie());
       TheCU.addUInt(TheCU.getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
                     dwarf::DW_FORM_data8, ID);
       SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
@@ -718,7 +744,9 @@ void DwarfDebug::endModule() {
   }
 
   // Emit the pubnames and pubtypes sections if requested.
-  if (HasDwarfPubSections) {
+  // The condition is optimistically correct - any CU not using GMLT (&
+  // implicit/default pubnames state) might still have pubnames.
+  if (hasDwarfPubSections(/* gmlt */ false)) {
     emitDebugPubNames(GenerateGnuPubSections);
     emitDebugPubTypes(GenerateGnuPubSections);
   }
@@ -1028,8 +1056,12 @@ void DwarfDebug::beginInstruction(const MachineInstr *MI) {
   DebugHandlerBase::beginInstruction(MI);
   assert(CurMI);
 
+  const auto *SP = MI->getParent()->getParent()->getFunction()->getSubprogram();
+  if (!SP || SP->getUnit()->getEmissionKind() == DICompileUnit::NoDebug)
+    return;
+
   // Check if source location changes, but ignore DBG_VALUE and CFI locations.
-  if (MI->isDebugValue() || MI->isCFIInstruction())
+  if (MI->isMetaInstruction())
     return;
   const DebugLoc &DL = MI->getDebugLoc();
   // When we emit a line-0 record, we don't update PrevInstLoc; so look at
@@ -1111,7 +1143,7 @@ static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
   // the beginning of the function body.
   for (const auto &MBB : *MF)
     for (const auto &MI : MBB)
-      if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
+      if (!MI.isMetaInstruction() && !MI.getFlag(MachineInstr::FrameSetup) &&
           MI.getDebugLoc())
         return MI.getDebugLoc();
   return DebugLoc();
@@ -1122,40 +1154,28 @@ static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
 void DwarfDebug::beginFunctionImpl(const MachineFunction *MF) {
   CurFn = MF;
 
-  if (LScopes.empty())
+  auto *SP = MF->getFunction()->getSubprogram();
+  assert(LScopes.empty() || SP == LScopes.getCurrentFunctionScope()->getScopeNode());
+  if (SP->getUnit()->getEmissionKind() == DICompileUnit::NoDebug)
     return;
 
+  DwarfCompileUnit &CU = getOrCreateDwarfCompileUnit(SP->getUnit());
+
   // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
   // belongs to so that we add to the correct per-cu line table in the
   // non-asm case.
-  LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
-  // FnScope->getScopeNode() and DI->second should represent the same function,
-  // though they may not be the same MDNode due to inline functions merged in
-  // LTO where the debug info metadata still differs (either due to distinct
-  // written differences - two versions of a linkonce_odr function
-  // written/copied into two separate files, or some sub-optimal metadata that
-  // isn't structurally identical (see: file path/name info from clang, which
-  // includes the directory of the cpp file being built, even when the file name
-  // is absolute (such as an <> lookup header)))
-  auto *SP = cast<DISubprogram>(FnScope->getScopeNode());
-  DwarfCompileUnit *TheCU = CUMap.lookup(SP->getUnit());
-  if (!TheCU) {
-    assert(SP->getUnit()->getEmissionKind() == DICompileUnit::NoDebug &&
-           "DICompileUnit missing from llvm.dbg.cu?");
-    return;
-  }
   if (Asm->OutStreamer->hasRawTextSupport())
     // Use a single line table if we are generating assembly.
     Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
   else
-    Asm->OutStreamer->getContext().setDwarfCompileUnitID(TheCU->getUniqueID());
+    Asm->OutStreamer->getContext().setDwarfCompileUnitID(CU.getUniqueID());
 
   // Record beginning of function.
   PrologEndLoc = findPrologueEndLoc(MF);
-  if (DILocation *L = PrologEndLoc) {
+  if (PrologEndLoc) {
     // We'd like to list the prologue as "not statements" but GDB behaves
     // poorly if we do that. Revisit this with caution/GDB (7.5+) testing.
-    auto *SP = L->getInlinedAtScope()->getSubprogram();
+    auto *SP = PrologEndLoc->getInlinedAtScope()->getSubprogram();
     recordSourceLine(SP->getScopeLine(), 0, SP, DWARF2_FLAG_IS_STMT);
   }
 }
@@ -1395,7 +1415,7 @@ void DwarfDebug::emitDebugPubSection(
 
     const auto &Globals = (TheU->*Accessor)();
 
-    if (Globals.empty())
+    if (!hasDwarfPubSections(TheU->includeMinimalInlineScopes()))
       continue;
 
     if (auto *Skeleton = TheU->getSkeleton())
@@ -1544,6 +1564,9 @@ void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) {
 
 // Emit locations into the debug loc section.
 void DwarfDebug::emitDebugLoc() {
+  if (DebugLocs.getLists().empty())
+    return;
+
   // Start the dwarf loc section.
   Asm->OutStreamer->SwitchSection(
       Asm->getObjFileLowering().getDwarfLocSection());
@@ -1755,6 +1778,9 @@ void DwarfDebug::emitDebugARanges() {
 
 /// Emit address ranges into a debug ranges section.
 void DwarfDebug::emitDebugRanges() {
+  if (CUMap.empty())
+    return;
+
   // Start the dwarf ranges section.
   Asm->OutStreamer->SwitchSection(
       Asm->getObjFileLowering().getDwarfRangesSection());
@@ -1834,6 +1860,9 @@ void DwarfDebug::emitMacroFile(DIMacroFile &F, DwarfCompileUnit &U) {
 
 /// Emit macros into a debug macinfo section.
 void DwarfDebug::emitDebugMacinfo() {
+  if (CUMap.empty())
+    return;
+
   // Start the dwarf macinfo section.
   Asm->OutStreamer->SwitchSection(
       Asm->getObjFileLowering().getDwarfMacinfoSection());
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h
index b9c5aa9ffb231..ebfba4cfc275a 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -246,9 +246,6 @@ class DwarfDebug : public DebugHandlerBase {
       std::pair<std::unique_ptr<DwarfTypeUnit>, const DICompositeType *>, 1>
       TypeUnitsUnderConstruction;
 
-  /// Whether to emit the pubnames/pubtypes sections.
-  bool HasDwarfPubSections;
-
   /// Whether to use the GNU TLS opcode (instead of the standard opcode).
   bool UseGNUTLSOpcode;
 
@@ -415,11 +412,11 @@ class DwarfDebug : public DebugHandlerBase {
 
   /// Flags to let the linker know we have emitted new style pubnames. Only
   /// emit it here if we don't have a skeleton CU for split dwarf.
-  void addGnuPubAttributes(DwarfUnit &U, DIE &D) const;
+  void addGnuPubAttributes(DwarfCompileUnit &U, DIE &D) const;
 
   /// Create new DwarfCompileUnit for the given metadata node with tag
   /// DW_TAG_compile_unit.
-  DwarfCompileUnit &constructDwarfCompileUnit(const DICompileUnit *DIUnit);
+  DwarfCompileUnit &getOrCreateDwarfCompileUnit(const DICompileUnit *DIUnit);
 
   /// Construct imported_module or imported_declaration DIE.
   void constructAndAddImportedEntityDIE(DwarfCompileUnit &TheCU,
@@ -556,6 +553,8 @@ public:
   /// A helper function to check whether the DIE for a given Scope is
   /// going to be null.
   bool isLexicalScopeDIENull(LexicalScope *Scope);
+
+  bool hasDwarfPubSections(bool includeMinimalInlineScopes) const;
 };
 } // End of namespace llvm