diff --git a/lldb/include/lldb/Core/dwarf.h b/lldb/include/lldb/Core/dwarf.h
--- a/lldb/include/lldb/Core/dwarf.h
+++ b/lldb/include/lldb/Core/dwarf.h
@@ -30,11 +30,12 @@
                             // any addresses in the compile units that get
                             // parsed
 
-typedef uint32_t dw_offset_t; // Dwarf Debug Information Entry offset for any
+typedef uint64_t dw_offset_t; // Dwarf Debug Information Entry offset for any
                               // offset into the file
 
 /* Constants */
-#define DW_INVALID_OFFSET (~(dw_offset_t)0)
+#define DW_DIE_OFFSET_MAX_BITSIZE 40
+#define DW_INVALID_OFFSET (((uint64_t)1u << DW_DIE_OFFSET_MAX_BITSIZE) - 1)
 #define DW_INVALID_INDEX 0xFFFFFFFFul
 
 // #define DW_ADDR_none 0x0
diff --git a/lldb/include/lldb/Symbol/DWARFCallFrameInfo.h b/lldb/include/lldb/Symbol/DWARFCallFrameInfo.h
--- a/lldb/include/lldb/Symbol/DWARFCallFrameInfo.h
+++ b/lldb/include/lldb/Symbol/DWARFCallFrameInfo.h
@@ -127,7 +127,7 @@
 
   void GetFDEIndex();
 
-  bool FDEToUnwindPlan(uint32_t offset, Address startaddr,
+  bool FDEToUnwindPlan(dw_offset_t offset, Address startaddr,
                        UnwindPlan &unwind_plan);
 
   const CIE *GetCIE(dw_offset_t cie_offset);
@@ -158,7 +158,7 @@
   Type m_type;
 
   CIESP
-  ParseCIE(const uint32_t cie_offset);
+  ParseCIE(const dw_offset_t cie_offset);
 
   lldb::RegisterKind GetRegisterKind() const {
     return m_type == EH ? lldb::eRegisterKindEHFrame : lldb::eRegisterKindDWARF;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DIERef.h b/lldb/source/Plugins/SymbolFile/DWARF/DIERef.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/DIERef.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DIERef.h
@@ -10,6 +10,7 @@
 #define LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_DIEREF_H
 
 #include "lldb/Core/dwarf.h"
+#include "lldb/Utility/LLDBAssert.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/Support/FormatProviders.h"
 #include <cassert>
@@ -26,17 +27,59 @@
 class DIERef {
 public:
   enum Section : uint8_t { DebugInfo, DebugTypes };
+  enum IndexType : uint8_t { DWONum, OSONum };
 
-  DIERef(llvm::Optional<uint32_t> dwo_num, Section section,
+  DIERef(llvm::Optional<uint32_t> dwo_oso_num, Section section,
          dw_offset_t die_offset)
-      : m_dwo_num(dwo_num.value_or(0)), m_dwo_num_valid(bool(dwo_num)),
-        m_section(section), m_die_offset(die_offset) {
-    assert(this->dwo_num() == dwo_num && "Dwo number out of range?");
+      : m_die_offset(die_offset), m_dwo_oso_num(dwo_oso_num.value_or(0)),
+        m_dwo_num_valid(dwo_oso_num ? true : false), m_oso_num_valid(0),
+        m_section(section) {
+    assert(this->dwo_num() == dwo_oso_num && "Dwo number out of range?");
+  }
+
+  DIERef(IndexType Type, llvm::Optional<uint32_t> dwo_oso_num, Section section,
+         dw_offset_t die_offset)
+      : m_die_offset(die_offset),
+        m_dwo_oso_num(Type == IndexType::DWONum ? dwo_oso_num.value_or(0) : 0),
+        m_dwo_num_valid(Type == IndexType::DWONum ? bool(dwo_oso_num) : false),
+        m_oso_num_valid(Type == IndexType::OSONum ? bool(dwo_oso_num) : false),
+        m_section(section) {
+    assert(((this->dwo_num() == dwo_oso_num && Type == IndexType::DWONum) ||
+            (this->oso_num() == dwo_oso_num && Type == IndexType::OSONum)) &&
+           "DWO/OSO number out of range?");
+  }
+
+  explicit DIERef(lldb::user_id_t uid) {
+    m_die_offset = uid & k_die_offset_mask;
+    m_dwo_num_valid = (uid & k_dwo_num_valid_bit) != 0;
+    m_oso_num_valid = (uid & k_oso_num_valid_bit) != 0;
+    m_dwo_oso_num =
+        m_dwo_num_valid ? (uid >> k_die_offset_bit_size) & k_dwo_num_mask : 0;
+    m_section =
+        (uid & k_section_bit) != 0 ? Section::DebugTypes : Section::DebugInfo;
+  }
+
+  lldb::user_id_t get_id() const {
+    return lldb::user_id_t(dwo_num().value_or(0)) << k_die_offset_bit_size |
+           die_offset() | (m_dwo_num_valid ? k_dwo_num_valid_bit : 0) |
+           (m_oso_num_valid ? k_oso_num_valid_bit : 0) |
+           (section() == Section::DebugTypes ? k_section_bit : 0);
+  }
+
+  void set_die_offset(dw_offset_t offset) {
+    lldbassert(offset <= DW_INVALID_OFFSET);
+    m_die_offset = offset;
   }
 
   llvm::Optional<uint32_t> dwo_num() const {
     if (m_dwo_num_valid)
-      return m_dwo_num;
+      return m_dwo_oso_num;
+    return llvm::None;
+  }
+
+  llvm::Optional<uint32_t> oso_num() const {
+    if (m_oso_num_valid)
+      return m_dwo_oso_num;
     return llvm::None;
   }
 
@@ -47,8 +90,10 @@
   bool operator<(DIERef other) const {
     if (m_dwo_num_valid != other.m_dwo_num_valid)
       return m_dwo_num_valid < other.m_dwo_num_valid;
-    if (m_dwo_num_valid && (m_dwo_num != other.m_dwo_num))
-      return m_dwo_num < other.m_dwo_num;
+    if (m_oso_num_valid != other.m_oso_num_valid)
+      return m_oso_num_valid < other.m_oso_num_valid;
+    if (m_dwo_num_valid && (m_dwo_oso_num != other.m_dwo_oso_num))
+      return m_dwo_oso_num < other.m_dwo_oso_num;
     if (m_section != other.m_section)
       return m_section < other.m_section;
     return m_die_offset < other.m_die_offset;
@@ -85,11 +130,34 @@
   ///
   void Encode(lldb_private::DataEncoder &encoder) const;
 
+  static constexpr uint64_t k_die_offset_bit_size = DW_DIE_OFFSET_MAX_BITSIZE;
+  static constexpr uint64_t k_dwo_num_bit_size =
+      64 - DW_DIE_OFFSET_MAX_BITSIZE - /* size of control bits */ 3;
+
+  static constexpr uint64_t k_dwo_num_valid_bit =
+      (1ull << (k_dwo_num_bit_size + k_die_offset_bit_size));
+  static constexpr uint64_t k_oso_num_valid_bit =
+      (1ull << (k_dwo_num_bit_size + k_die_offset_bit_size + 1));
+  static constexpr uint64_t k_section_bit =
+      (1ull << (k_dwo_num_bit_size + k_die_offset_bit_size + 2));
+
+  static constexpr uint64_t
+      k_dwo_num_mask = (~0ull) >> (64 - k_dwo_num_bit_size); // 0x1fffff;
+  static constexpr uint64_t k_die_offset_mask = (~0ull) >>
+                                                (64 - k_die_offset_bit_size);
+
 private:
-  uint32_t m_dwo_num : 30;
-  uint32_t m_dwo_num_valid : 1;
-  uint32_t m_section : 1;
-  dw_offset_t m_die_offset;
+  // Allow 2TB of .debug_info/.debug_types offset
+  dw_offset_t m_die_offset : k_die_offset_bit_size;
+  // Used for DWO index or for .o file index on mac
+  dw_offset_t m_dwo_oso_num : k_dwo_num_bit_size;
+  // Set to 1 if m_file_index is a DWO number
+  dw_offset_t m_dwo_num_valid : 1;
+  // Set to 1 if m_file_index is a N_OSO index for mac debugging without a dSYM
+  // file
+  dw_offset_t m_oso_num_valid : 1;
+  // Set to 0 for .debug_info 1 for .debug_types,
+  dw_offset_t m_section : 1;
 };
 static_assert(sizeof(DIERef) == 8);
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DIERef.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DIERef.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DIERef.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DIERef.cpp
@@ -22,34 +22,16 @@
   OS << "/" << format_hex_no_prefix(ref.die_offset(), 8);
 }
 
-constexpr uint32_t k_dwo_num_mask = 0x3FFFFFFF;
-constexpr uint32_t k_dwo_num_valid_bitmask = (1u << 30);
-constexpr uint32_t k_section_bitmask = (1u << 31);
-
 llvm::Optional<DIERef> DIERef::Decode(const DataExtractor &data,
                                       lldb::offset_t *offset_ptr) {
-  const uint32_t bitfield_storage = data.GetU32(offset_ptr);
-  uint32_t dwo_num = bitfield_storage & k_dwo_num_mask;
-  bool dwo_num_valid = (bitfield_storage & (k_dwo_num_valid_bitmask)) != 0;
-  Section section = (Section)((bitfield_storage & (k_section_bitmask)) != 0);
+  DIERef die_ref(data.GetU64(offset_ptr));
+
   // DIE offsets can't be zero and if we fail to decode something from data,
   // it will return 0
-  dw_offset_t die_offset = data.GetU32(offset_ptr);
-  if (die_offset == 0)
+  if (!die_ref.die_offset())
     return llvm::None;
-  if (dwo_num_valid)
-    return DIERef(dwo_num, section, die_offset);
-  else
-    return DIERef(llvm::None, section, die_offset);
-}
 
-void DIERef::Encode(DataEncoder &encoder) const {
-  uint32_t bitfield_storage = m_dwo_num;
-  if (m_dwo_num_valid)
-    bitfield_storage |= k_dwo_num_valid_bitmask;
-  if (m_section)
-    bitfield_storage |= k_section_bitmask;
-  encoder.AppendU32(bitfield_storage);
-  static_assert(sizeof(m_die_offset) == 4, "m_die_offset must be 4 bytes");
-  encoder.AppendU32(m_die_offset);
+  return die_ref;
 }
+
+void DIERef::Encode(DataEncoder &encoder) const { encoder.AppendU64(get_id()); }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -258,7 +258,7 @@
       return;
     die.GetDWARF()->GetObjectFile()->GetModule()->ReportError(
         "Unable to complete the Decl context for DIE '%s' at offset "
-        "0x%8.8x.\nPlease file a bug report.",
+        "0x%16.16" PRIx64 ".\nPlease file a bug report.",
         type_name_cstr ? type_name_cstr : "", die.GetOffset());
   }
 
@@ -428,7 +428,8 @@
     dwarf->GetObjectFile()->GetModule()->LogMessage(
         log,
         "DWARFASTParserClang::ParseTypeFromDWARF "
-        "(die = 0x%8.8x, decl_ctx = %p (die 0x%8.8x)) %s name = '%s')",
+        "(die = 0x%16.16" PRIx64 ", decl_ctx = %p (die 0x%16.16" PRIx64
+        ")) %s name = '%s')",
         die.GetOffset(), static_cast<void *>(context), context_die.GetOffset(),
         die.GetTagAsCString(), die.GetName());
   }
@@ -505,7 +506,8 @@
   }
   default:
     dwarf->GetObjectFile()->GetModule()->ReportError(
-        "{0x%8.8x}: unhandled type tag 0x%4.4x (%s), please file a bug and "
+        "{0x%16.16" PRIx64
+        "}: unhandled type tag 0x%4.4x (%s), please file a bug and "
         "attach the file at the start of this error message",
         die.GetOffset(), tag, DW_TAG_value_to_name(tag));
     break;
@@ -674,7 +676,7 @@
           if (log)
             dwarf->GetObjectFile()->GetModule()->LogMessage(
                 log,
-                "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
+                "SymbolFileDWARF::ParseType (die = 0x%16.16" PRIx64 ") %s '%s' "
                 "is Objective-C 'id' built-in type.",
                 die.GetOffset(), die.GetTagAsCString(), die.GetName());
           clang_type = m_ast.GetBasicType(eBasicTypeObjCID);
@@ -685,7 +687,7 @@
           if (log)
             dwarf->GetObjectFile()->GetModule()->LogMessage(
                 log,
-                "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
+                "SymbolFileDWARF::ParseType (die = 0x%16.16" PRIx64 ") %s '%s' "
                 "is Objective-C 'Class' built-in type.",
                 die.GetOffset(), die.GetTagAsCString(), die.GetName());
           clang_type = m_ast.GetBasicType(eBasicTypeObjCClass);
@@ -696,7 +698,7 @@
           if (log)
             dwarf->GetObjectFile()->GetModule()->LogMessage(
                 log,
-                "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s '%s' "
+                "SymbolFileDWARF::ParseType (die = 0x%16.16" PRIx64 ") %s '%s' "
                 "is Objective-C 'selector' built-in type.",
                 die.GetOffset(), die.GetTagAsCString(), die.GetName());
           clang_type = m_ast.GetBasicType(eBasicTypeObjCSel);
@@ -717,7 +719,7 @@
             if (log)
               dwarf->GetObjectFile()->GetModule()->LogMessage(
                   log,
-                  "SymbolFileDWARF::ParseType (die = 0x%8.8x) %s "
+                  "SymbolFileDWARF::ParseType (die = 0x%16.16" PRIx64 ") %s "
                   "'%s' is 'objc_object*', which we overrode to "
                   "'id'.",
                   die.GetOffset(), die.GetTagAsCString(), die.GetName());
@@ -771,7 +773,7 @@
       if (log) {
         dwarf->GetObjectFile()->GetModule()->LogMessage(
             log,
-            "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" is a "
+            "SymbolFileDWARF(%p) - 0x%16.16" PRIx64 ": %s type \"%s\" is a "
             "forward declaration, complete type is 0x%8.8" PRIx64,
             static_cast<void *>(this), die.GetOffset(),
             DW_TAG_value_to_name(tag), attrs.name.GetCString(),
@@ -841,7 +843,8 @@
     TypeSystemClang::CompleteTagDeclarationDefinition(clang_type);
   } else {
     dwarf->GetObjectFile()->GetModule()->ReportError(
-        "DWARF DIE at 0x%8.8x named \"%s\" was not able to start its "
+        "DWARF DIE at 0x%16.16" PRIx64
+        " named \"%s\" was not able to start its "
         "definition.\nPlease file a bug and attach the file at the "
         "start of this error message",
         die.GetOffset(), attrs.name.GetCString());
@@ -1004,7 +1007,8 @@
             m_ast.SetMetadataAsUserID(objc_method_decl, die.GetID());
           } else {
             dwarf->GetObjectFile()->GetModule()->ReportError(
-                "{0x%8.8x}: invalid Objective-C method 0x%4.4x (%s), "
+                "{0x%16.16" PRIx64
+                "}: invalid Objective-C method 0x%4.4x (%s), "
                 "please file a bug and attach the file at the start of "
                 "this error message",
                 die.GetOffset(), tag, DW_TAG_value_to_name(tag));
@@ -1057,7 +1061,7 @@
               LinkDeclContextToDIE(spec_clang_decl_ctx, die);
             } else {
               dwarf->GetObjectFile()->GetModule()->ReportWarning(
-                  "0x%8.8" PRIx64 ": DW_AT_specification(0x%8.8x"
+                  "0x%8.8" PRIx64 ": DW_AT_specification(0x%16.16" PRIx64 ""
                   ") has no decl\n",
                   die.GetID(), spec_die.GetOffset());
             }
@@ -1076,7 +1080,7 @@
               LinkDeclContextToDIE(abs_clang_decl_ctx, die);
             } else {
               dwarf->GetObjectFile()->GetModule()->ReportWarning(
-                  "0x%8.8" PRIx64 ": DW_AT_abstract_origin(0x%8.8x"
+                  "0x%8.8" PRIx64 ": DW_AT_abstract_origin(0x%16.16" PRIx64 ""
                   ") has no decl\n",
                   die.GetID(), abs_die.GetOffset());
             }
@@ -1428,14 +1432,14 @@
 
   Type *base_class_type = die.ResolveTypeUID(encoding_form.Reference());
   if (base_class_type == nullptr) {
-    module_sp->ReportError("0x%8.8x: DW_TAG_inheritance failed to "
-                           "resolve the base class at 0x%8.8x"
-                           " from enclosing type 0x%8.8x. \nPlease file "
-                           "a bug and attach the file at the start of "
-                           "this error message",
-                           die.GetOffset(),
-                           encoding_form.Reference().GetOffset(),
-                           parent_die.GetOffset());
+    module_sp->ReportError(
+        "0x%16.16" PRIx64 ": DW_TAG_inheritance failed to "
+        "resolve the base class at 0x%16.16" PRIx64 ""
+        " from enclosing type 0x%16.16" PRIx64 ". \nPlease file "
+        "a bug and attach the file at the start of "
+        "this error message",
+        die.GetOffset(), encoding_form.Reference().GetOffset(),
+        parent_die.GetOffset());
     return;
   }
 
@@ -1695,7 +1699,7 @@
         if (log) {
           dwarf->GetObjectFile()->GetModule()->LogMessage(
               log,
-              "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" is an "
+              "SymbolFileDWARF(%p) - 0x%16.16" PRIx64 ": %s type \"%s\" is an "
               "incomplete objc type, complete type is 0x%8.8" PRIx64,
               static_cast<void *>(this), die.GetOffset(),
               DW_TAG_value_to_name(tag), attrs.name.GetCString(),
@@ -1720,7 +1724,7 @@
     if (log) {
       dwarf->GetObjectFile()->GetModule()->LogMessage(
           log,
-          "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" is a "
+          "SymbolFileDWARF(%p) - 0x%16.16" PRIx64 ": %s type \"%s\" is a "
           "forward declaration, trying to find complete type",
           static_cast<void *>(this), die.GetOffset(), DW_TAG_value_to_name(tag),
           attrs.name.GetCString());
@@ -1752,7 +1756,7 @@
       if (log) {
         dwarf->GetObjectFile()->GetModule()->LogMessage(
             log,
-            "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" is a "
+            "SymbolFileDWARF(%p) - 0x%16.16" PRIx64 ": %s type \"%s\" is a "
             "forward declaration, complete type is 0x%8.8" PRIx64,
             static_cast<void *>(this), die.GetOffset(),
             DW_TAG_value_to_name(tag), attrs.name.GetCString(),
@@ -1806,7 +1810,7 @@
         if (log) {
           dwarf->GetObjectFile()->GetModule()->LogMessage(
               log,
-              "SymbolFileDWARF(%p) - 0x%8.8x: %s type \"%s\" "
+              "SymbolFileDWARF(%p) - 0x%16.16" PRIx64 ": %s type \"%s\" "
               "clang::ClassTemplateDecl failed to return a decl.",
               static_cast<void *>(this), die.GetOffset(),
               DW_TAG_value_to_name(tag), attrs.name.GetCString());
@@ -1866,7 +1870,8 @@
         TypeSystemClang::CompleteTagDeclarationDefinition(clang_type);
       } else {
         dwarf->GetObjectFile()->GetModule()->ReportError(
-            "DWARF DIE at 0x%8.8x named \"%s\" was not able to start its "
+            "DWARF DIE at 0x%16.16" PRIx64
+            " named \"%s\" was not able to start its "
             "definition.\nPlease file a bug and attach the file at the "
             "start of this error message",
             die.GetOffset(), attrs.name.GetCString());
@@ -2675,11 +2680,12 @@
 
   Type *member_type = die.ResolveTypeUID(attrs.encoding_form.Reference());
   if (!member_type) {
-    module_sp->ReportError("0x%8.8" PRIx64
-                           ": DW_TAG_APPLE_property '%s' refers to type 0x%8.8x"
-                           " which was unable to be parsed",
-                           die.GetID(), propAttrs.prop_name,
-                           attrs.encoding_form.Reference().GetOffset());
+    module_sp->ReportError(
+        "0x%8.8" PRIx64
+        ": DW_TAG_APPLE_property '%s' refers to type 0x%16.16" PRIx64 ""
+        " which was unable to be parsed",
+        die.GetID(), propAttrs.prop_name,
+        attrs.encoding_form.Reference().GetOffset());
     return;
   }
 
@@ -2815,12 +2821,13 @@
   if (!member_type) {
     if (attrs.name)
       module_sp->ReportError(
-          "0x%8.8" PRIx64 ": DW_TAG_member '%s' refers to type 0x%8.8x"
+          "0x%8.8" PRIx64 ": DW_TAG_member '%s' refers to type 0x%16.16" PRIx64
+          ""
           " which was unable to be parsed",
           die.GetID(), attrs.name, attrs.encoding_form.Reference().GetOffset());
     else
       module_sp->ReportError(
-          "0x%8.8" PRIx64 ": DW_TAG_member refers to type 0x%8.8x"
+          "0x%8.8" PRIx64 ": DW_TAG_member refers to type 0x%16.16" PRIx64 ""
           " which was unable to be parsed",
           die.GetID(), attrs.encoding_form.Reference().GetOffset());
     return;
@@ -2991,11 +2998,11 @@
             (member_array_size != 0 ||
              attrs.member_byte_offset > parent_byte_size)) {
           module_sp->ReportError(
-              "0x%8.8" PRIx64 ": DW_TAG_member '%s' refers to type 0x%8.8x"
+              "0x%8.8" PRIx64
+              ": DW_TAG_member '%s' refers to type 0x%16.16" PRIx64 ""
               " which extends beyond the bounds of 0x%8.8" PRIx64,
               die.GetID(), attrs.name,
-              attrs.encoding_form.Reference().GetOffset(),
-              parent_die.GetID());
+              attrs.encoding_form.Reference().GetOffset(), parent_die.GetID());
         }
 
         member_clang_type =
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp
@@ -18,10 +18,11 @@
 using namespace lldb_private;
 
 void DWARFCompileUnit::Dump(Stream *s) const {
-  s->Printf("0x%8.8x: Compile Unit: length = 0x%8.8x, version = 0x%4.4x, "
+  s->Printf("0x%16.16" PRIx64
+            ": Compile Unit: length = 0x%8.8x, version = 0x%4.4x, "
             "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
-            "{0x%8.8x})\n",
-            GetOffset(), GetLength(), GetVersion(), GetAbbrevOffset(),
+            "{0x%16.16" PRIx64 "})\n",
+            GetOffset(), GetLength(), GetVersion(), (uint32_t)GetAbbrevOffset(),
             GetAddressByteSize(), GetNextUnitOffset());
 }
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfo.cpp
@@ -128,7 +128,7 @@
       });
   uint32_t idx = std::distance(m_units.begin(), pos);
   if (idx == 0)
-    return DW_INVALID_OFFSET;
+    return DW_INVALID_INDEX;
   return idx - 1;
 }
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h
@@ -35,7 +35,8 @@
   typedef collection::const_iterator const_iterator;
 
   DWARFDebugInfoEntry()
-      : m_offset(DW_INVALID_OFFSET), m_sibling_idx(0), m_has_children(false) {}
+      : m_offset(DW_INVALID_OFFSET), m_parent_idx(0), m_sibling_idx(0),
+        m_has_children(false) {}
 
   explicit operator bool() const { return m_offset != DW_INVALID_OFFSET; }
   bool operator==(const DWARFDebugInfoEntry &rhs) const;
@@ -164,14 +165,16 @@
   static DWARFDeclContext
   GetDWARFDeclContextStatic(const DWARFDebugInfoEntry *die, DWARFUnit *cu);
 
-  dw_offset_t m_offset; // Offset within the .debug_info/.debug_types
-  uint32_t m_parent_idx = 0;   // How many to subtract from "this" to get the
-                               // parent. If zero this die has no parent
-  uint32_t m_sibling_idx : 31, // How many to add to "this" to get the sibling.
-      // If it is zero, then the DIE doesn't have children, or the
-      // DWARF claimed it had children but the DIE only contained
-      // a single NULL terminating child.
-      m_has_children : 1;
+  // Up to 2TB offset within the .debug_info/.debug_types
+  dw_offset_t m_offset : DW_DIE_OFFSET_MAX_BITSIZE;
+  // How many to subtract from "this" to get the parent. If zero this die has no
+  // parent
+  dw_offset_t m_parent_idx : 64 - DW_DIE_OFFSET_MAX_BITSIZE;
+  // How many to add to "this" to get the sibling.
+  // If it is zero, then the DIE doesn't have children,
+  // or the DWARF claimed it had children but the DIE
+  // only contained a single NULL terminating child.
+  uint32_t m_sibling_idx : 31, m_has_children : 1;
   uint16_t m_abbr_idx = 0;
   /// A copy of the DW_TAG value so we don't have to go through the compile
   /// unit abbrev table
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp
@@ -60,7 +60,8 @@
   const auto *abbrevDecl = GetAbbreviationDeclarationPtr(cu);
   if (abbrevDecl == nullptr) {
     cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
-        "{0x%8.8x}: invalid abbreviation code %u, please file a bug and "
+        "{0x%16.16" PRIx64
+        "}: invalid abbreviation code %u, please file a bug and "
         "attach the file at the start of this error message",
         m_offset, (unsigned)abbr_idx);
     // WE can't parse anymore if the DWARF is borked...
@@ -190,7 +191,8 @@
 
         default:
           cu->GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
-              "{0x%8.8x}: Unsupported DW_FORM_0x%x, please file a bug and "
+              "{0x%16.16" PRIx64
+              "}: Unsupported DW_FORM_0x%x, please file a bug and "
               "attach the file at the start of this error message",
               m_offset, (unsigned)form);
           *offset_ptr = m_offset;
@@ -215,7 +217,8 @@
   if (expected_ranges)
     return std::move(*expected_ranges);
   unit.GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
-      "{0x%8.8x}: DIE has DW_AT_ranges(%s 0x%" PRIx64 ") attribute, but "
+      "{0x%16.16" PRIx64 "}: DIE has DW_AT_ranges(%s 0x%" PRIx64
+      ") attribute, but "
       "range extraction failed (%s), please file a bug "
       "and attach the file at the start of this error message",
       die.GetOffset(),
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFIndex.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFIndex.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFIndex.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFIndex.cpp
@@ -102,6 +102,6 @@
 void DWARFIndex::ReportInvalidDIERef(DIERef ref, llvm::StringRef name) const {
   m_module.ReportErrorIfModifyDetected(
       "the DWARF debug information has been modified (accelerator table had "
-      "bad die 0x%8.8x for '%s')\n",
+      "bad die 0x%16.16" PRIx64 " for '%s')\n",
       ref.die_offset(), name.str().c_str());
 }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFTypeUnit.cpp
@@ -15,9 +15,10 @@
 using namespace lldb_private;
 
 void DWARFTypeUnit::Dump(Stream *s) const {
-  s->Printf("0x%8.8x: Type Unit: length = 0x%8.8x, version = 0x%4.4x, "
-            "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
-            "{0x%8.8x})\n",
-            GetOffset(), GetLength(), GetVersion(), GetAbbrevOffset(),
-            GetAddressByteSize(), GetNextUnitOffset());
+  s->Printf(
+      "0x%16.16" PRIx64 ": Type Unit: length = 0x%8.8x, version = 0x%4.4x, "
+      "abbr_offset = 0x%8.8x, addr_size = 0x%2.2x (next CU at "
+      "{0x%16.16" PRIx64 "})\n",
+      GetOffset(), (uint32_t)GetLength(), GetVersion(),
+      (uint32_t)GetAbbrevOffset(), GetAddressByteSize(), GetNextUnitOffset());
 }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
@@ -87,11 +87,11 @@
   DWARFUnit *dwo_cu = dwo_symbol_file->GetDWOCompileUnitForHash(*m_dwo_id);
 
   if (!dwo_cu) {
-    SetDwoError(
-        Status("unable to load .dwo file from \"%s\" due to ID (0x%16.16" PRIx64
-               ") mismatch for skeleton DIE at 0x%8.8" PRIx32,
-               dwo_symbol_file->GetObjectFile()->GetFileSpec().GetPath().c_str(),
-               *m_dwo_id, m_first_die.GetOffset()));
+    SetDwoError(Status(
+        "unable to load .dwo file from \"%s\" due to ID (0x%16.16" PRIx64
+        ") mismatch for skeleton DIE at 0x%8.8" PRIx32,
+        dwo_symbol_file->GetObjectFile()->GetFileSpec().GetPath().c_str(),
+        *m_dwo_id, (uint32_t)m_first_die.GetOffset()));
     return; // Can't fetch the compile unit from the dwo file.
   }
   dwo_cu->SetUserData(this);
@@ -101,7 +101,8 @@
     // Can't fetch the compile unit DIE from the dwo file.
     SetDwoError(
         Status("unable to extract compile unit DIE from .dwo file for skeleton "
-               "DIE at 0x%8.8" PRIx32, m_first_die.GetOffset()));
+               "DIE at 0x%8.8" PRIx32,
+               (uint32_t)m_first_die.GetOffset()));
     return;
   }
 
@@ -212,7 +213,8 @@
   llvm::sys::ScopedWriter first_die_lock(m_first_die_mutex);
 
   ElapsedTime elapsed(m_dwarf.GetDebugInfoParseTimeRef());
-  LLDB_SCOPED_TIMERF("%8.8x: DWARFUnit::ExtractDIEsIfNeeded()", GetOffset());
+  LLDB_SCOPED_TIMERF("%16.16" PRIx64 ": DWARFUnit::ExtractDIEsIfNeeded()",
+                     GetOffset());
 
   // Set the offset to that of the first DIE and calculate the start of the
   // next compilation unit header.
@@ -636,7 +638,7 @@
 
   if (!ContainsDIEOffset(die_offset)) {
     GetSymbolFileDWARF().GetObjectFile()->GetModule()->ReportError(
-        "GetDIE for DIE 0x%" PRIx32 " is outside of its CU 0x%" PRIx32,
+        "GetDIE for DIE 0x%" PRIx64 " is outside of its CU 0x%" PRIx64,
         die_offset, GetOffset());
     return DWARFDIE(); // Not found
   }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp b/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
@@ -142,7 +142,9 @@
 
   if (log) {
     m_module.LogMessage(
-        log, "ManualDWARFIndex::IndexUnit for unit at .debug_info[0x%8.8x]",
+        log,
+        "ManualDWARFIndex::IndexUnit for unit at .debug_info[0x%16.16" PRIx64
+        "]",
         unit.GetOffset());
   }
 
@@ -524,7 +526,10 @@
   kDataIDEnd = 255u,
 
 };
-constexpr uint32_t CURRENT_CACHE_VERSION = 1;
+
+// Version 2 changes the encoding of DIERef objects used in the DWARF manual
+// index name tables. See DIERef class for details.
+constexpr uint32_t CURRENT_CACHE_VERSION = 2;
 
 bool ManualDWARFIndex::IndexSet::Decode(const DataExtractor &data,
                                         lldb::offset_t *offset_ptr) {
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -8,11 +8,30 @@
 
 #include "SymbolFileDWARF.h"
 
-#include "llvm/ADT/Optional.h"
-#include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
-#include "llvm/Support/Casting.h"
-#include "llvm/Support/Threading.h"
-
+#include "AppleDWARFIndex.h"
+#include "DIERef.h"
+#include "DWARFASTParser.h"
+#include "DWARFASTParserClang.h"
+#include "DWARFCompileUnit.h"
+#include "DWARFDebugAbbrev.h"
+#include "DWARFDebugAranges.h"
+#include "DWARFDebugInfo.h"
+#include "DWARFDebugMacro.h"
+#include "DWARFDebugRanges.h"
+#include "DWARFDeclContext.h"
+#include "DWARFFormValue.h"
+#include "DWARFTypeUnit.h"
+#include "DWARFUnit.h"
+#include "DebugNamesDWARFIndex.h"
+#include "LogChannelDWARF.h"
+#include "ManualDWARFIndex.h"
+#include "Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.h"
+#include "Plugins/ExpressionParser/Clang/ClangUtil.h"
+#include "Plugins/Language/CPlusPlus/CPlusPlusLanguage.h"
+#include "Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h"
+#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
+#include "SymbolFileDWARFDebugMap.h"
+#include "SymbolFileDWARFDwo.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleList.h"
 #include "lldb/Core/ModuleSpec.h"
@@ -21,25 +40,10 @@
 #include "lldb/Core/Section.h"
 #include "lldb/Core/StreamFile.h"
 #include "lldb/Core/Value.h"
-#include "lldb/Utility/ArchSpec.h"
-#include "lldb/Utility/LLDBLog.h"
-#include "lldb/Utility/RegularExpression.h"
-#include "lldb/Utility/Scalar.h"
-#include "lldb/Utility/StreamString.h"
-#include "lldb/Utility/Timer.h"
-
-#include "Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.h"
-#include "Plugins/Language/CPlusPlus/CPlusPlusLanguage.h"
-
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Host/Host.h"
-
 #include "lldb/Interpreter/OptionValueFileSpecList.h"
 #include "lldb/Interpreter/OptionValueProperties.h"
-
-#include "Plugins/ExpressionParser/Clang/ClangUtil.h"
-#include "Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.h"
-#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
 #include "lldb/Symbol/Block.h"
 #include "lldb/Symbol/CompileUnit.h"
 #include "lldb/Symbol/CompilerDecl.h"
@@ -52,39 +56,26 @@
 #include "lldb/Symbol/TypeMap.h"
 #include "lldb/Symbol/TypeSystem.h"
 #include "lldb/Symbol/VariableList.h"
-
 #include "lldb/Target/Language.h"
 #include "lldb/Target/Target.h"
-
-#include "AppleDWARFIndex.h"
-#include "DWARFASTParser.h"
-#include "DWARFASTParserClang.h"
-#include "DWARFCompileUnit.h"
-#include "DWARFDebugAbbrev.h"
-#include "DWARFDebugAranges.h"
-#include "DWARFDebugInfo.h"
-#include "DWARFDebugMacro.h"
-#include "DWARFDebugRanges.h"
-#include "DWARFDeclContext.h"
-#include "DWARFFormValue.h"
-#include "DWARFTypeUnit.h"
-#include "DWARFUnit.h"
-#include "DebugNamesDWARFIndex.h"
-#include "LogChannelDWARF.h"
-#include "ManualDWARFIndex.h"
-#include "SymbolFileDWARFDebugMap.h"
-#include "SymbolFileDWARFDwo.h"
-
+#include "lldb/Utility/ArchSpec.h"
+#include "lldb/Utility/LLDBLog.h"
+#include "lldb/Utility/RegularExpression.h"
+#include "lldb/Utility/Scalar.h"
+#include "lldb/Utility/StreamString.h"
+#include "lldb/Utility/Timer.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
+#include "llvm/Support/Casting.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormatVariadic.h"
-
+#include "llvm/Support/Threading.h"
 #include <algorithm>
-#include <map>
-#include <memory>
-
 #include <cctype>
 #include <cstring>
+#include <map>
+#include <memory>
 
 //#define ENABLE_DEBUG_PRINTF // COMMENT OUT THIS LINE PRIOR TO CHECKIN
 
@@ -587,6 +578,15 @@
       }
     }
 
+    constexpr uint64_t MaxDebugInfoSize = (1ull) << DW_DIE_OFFSET_MAX_BITSIZE;
+    if (debug_info_file_size >= MaxDebugInfoSize) {
+      m_objfile_sp->GetModule()->ReportWarning(
+          "SymbolFileDWARF can't load this DWARF. It's larger then "
+          "0x%16.16" PRIx64 "",
+          MaxDebugInfoSize);
+      return 0;
+    }
+
     if (debug_abbrev_file_size > 0 && debug_info_file_size > 0)
       abilities |= CompileUnits | Functions | Blocks | GlobalVariables |
                    LocalVariables | VariableTypes;
@@ -1397,13 +1397,13 @@
 }
 
 user_id_t SymbolFileDWARF::GetUID(DIERef ref) {
-  if (GetDebugMapSymfile())
-    return GetID() | ref.die_offset();
+  if (GetDebugMapSymfile()) {
+    DIERef die_ref(GetID());
+    die_ref.set_die_offset(ref.die_offset());
+    return die_ref.get_id();
+  }
 
-  lldbassert(GetDwoNum().value_or(0) <= 0x3fffffff);
-  return user_id_t(GetDwoNum().value_or(0)) << 32 | ref.die_offset() |
-         lldb::user_id_t(GetDwoNum().has_value()) << 62 |
-         lldb::user_id_t(ref.section() == DIERef::Section::DebugTypes) << 63;
+  return DIERef(GetDwoNum(), ref.section(), ref.die_offset()).get_id();
 }
 
 llvm::Optional<SymbolFileDWARF::DecodedUID>
@@ -1418,25 +1418,18 @@
   // references to other DWARF objects and we must be ready to receive a
   // "lldb::user_id_t" that specifies a DIE from another SymbolFileDWARF
   // instance.
+  DIERef die_ref(uid);
   if (SymbolFileDWARFDebugMap *debug_map = GetDebugMapSymfile()) {
     SymbolFileDWARF *dwarf = debug_map->GetSymbolFileByOSOIndex(
         debug_map->GetOSOIndexFromUserID(uid));
     return DecodedUID{
-        *dwarf, {llvm::None, DIERef::Section::DebugInfo, dw_offset_t(uid)}};
+        *dwarf, {llvm::None, DIERef::Section::DebugInfo, die_ref.die_offset()}};
   }
-  dw_offset_t die_offset = uid;
-  if (die_offset == DW_INVALID_OFFSET)
-    return llvm::None;
-
-  DIERef::Section section =
-      uid >> 63 ? DIERef::Section::DebugTypes : DIERef::Section::DebugInfo;
 
-  llvm::Optional<uint32_t> dwo_num;
-  bool dwo_valid = uid >> 62 & 1;
-  if (dwo_valid)
-    dwo_num = uid >> 32 & 0x3fffffff;
+  if (die_ref.die_offset() == DW_INVALID_OFFSET)
+    return llvm::None;
 
-  return DecodedUID{*this, {dwo_num, section, die_offset}};
+  return DecodedUID{*this, die_ref};
 }
 
 DWARFDIE
@@ -1520,7 +1513,8 @@
     Log *log = GetLog(DWARFLog::DebugInfo);
     if (log)
       GetObjectFile()->GetModule()->LogMessage(
-          log, "SymbolFileDWARF::ResolveTypeUID (die = 0x%8.8x) %s '%s'",
+          log,
+          "SymbolFileDWARF::ResolveTypeUID (die = 0x%16.16" PRIx64 ") %s '%s'",
           die.GetOffset(), die.GetTagAsCString(), die.GetName());
 
     // We might be coming in in the middle of a type tree (a class within a
@@ -1537,8 +1531,9 @@
           if (log)
             GetObjectFile()->GetModule()->LogMessage(
                 log,
-                "SymbolFileDWARF::ResolveTypeUID (die = 0x%8.8x) %s '%s' "
-                "resolve parent forward type for 0x%8.8x",
+                "SymbolFileDWARF::ResolveTypeUID (die = 0x%16.16" PRIx64
+                ") %s '%s' "
+                "resolve parent forward type for 0x%16.16" PRIx64 "",
                 die.GetOffset(), die.GetTagAsCString(), die.GetName(),
                 decl_ctx_die.GetOffset());
         } break;
@@ -1629,7 +1624,7 @@
         return type;
 
       GetObjectFile()->GetModule()->ReportError(
-          "Parsing a die that is being parsed die: 0x%8.8x: %s %s",
+          "Parsing a die that is being parsed die: 0x%16.16" PRIx64 ": %s %s",
           die.GetOffset(), die.GetTagAsCString(), die.GetName());
 
     } else
@@ -1694,7 +1689,7 @@
 DWARFDIE
 SymbolFileDWARF::GetDIE(const DIERef &die_ref) {
   if (die_ref.dwo_num()) {
-    SymbolFileDWARF *dwarf = *die_ref.dwo_num() == 0x3fffffff
+    SymbolFileDWARF *dwarf = *die_ref.dwo_num() == DIERef::k_dwo_num_mask
                                  ? m_dwp_symfile.get()
                                  : this->DebugInfo()
                                        .GetUnitAtIndex(*die_ref.dwo_num())
@@ -1744,7 +1739,7 @@
 
   const char *dwo_name = GetDWOName(*dwarf_cu, cu_die);
   if (!dwo_name) {
-    unit.SetDwoError(Status("missing DWO name in skeleton DIE 0x%8.8" PRIx32,
+    unit.SetDwoError(Status("missing DWO name in skeleton DIE 0x%16.16" PRIx64,
                             cu_die.GetOffset()));
     return nullptr;
   }
@@ -1761,8 +1756,9 @@
     if (!comp_dir) {
       unit.SetDwoError(
           Status("unable to locate relative .dwo debug file \"%s\" for "
-                 "skeleton DIE 0x%8.8" PRIx32 " without valid DW_AT_comp_dir "
-                 "attribute", dwo_name, cu_die.GetOffset()));
+                 "skeleton DIE 0x%16.16" PRIx64 " without valid DW_AT_comp_dir "
+                 "attribute",
+                 dwo_name, cu_die.GetOffset()));
       return nullptr;
     }
 
@@ -1781,8 +1777,8 @@
   if (!FileSystem::Instance().Exists(dwo_file)) {
     unit.SetDwoError(
         Status("unable to locate .dwo debug file \"%s\" for skeleton DIE "
-               "0x%8.8" PRIx32, dwo_file.GetPath().c_str(),
-               cu_die.GetOffset()));
+               "0x%16.16" PRIx64,
+               dwo_file.GetPath().c_str(), cu_die.GetOffset()));
 
     if (m_dwo_warning_issued.test_and_set(std::memory_order_relaxed) == false) {
       GetObjectFile()->GetModule()->ReportWarning(
@@ -1801,8 +1797,9 @@
       dwo_file_data_offset);
   if (dwo_obj_file == nullptr) {
     unit.SetDwoError(
-          Status("unable to load object file for .dwo debug file \"%s\" for "
-                 "unit DIE 0x%8.8" PRIx32, dwo_name, cu_die.GetOffset()));
+        Status("unable to load object file for .dwo debug file \"%s\" for "
+               "unit DIE 0x%16.16" PRIx64,
+               dwo_name, cu_die.GetOffset()));
     return nullptr;
   }
 
@@ -1878,7 +1875,8 @@
                                                nullptr, nullptr, nullptr);
     if (!module_sp) {
       GetObjectFile()->GetModule()->ReportWarning(
-          "0x%8.8x: unable to locate module needed for external types: "
+          "0x%16.16" PRIx64
+          ": unable to locate module needed for external types: "
           "%s\nerror: %s\nDebugging will be degraded due to missing "
           "types. Rebuilding the project will regenerate the needed "
           "module files.",
@@ -1903,7 +1901,8 @@
 
     if (dwo_id != dwo_dwo_id) {
       GetObjectFile()->GetModule()->ReportWarning(
-          "0x%8.8x: Module %s is out-of-date (hash mismatch). Type information "
+          "0x%16.16" PRIx64 ": Module %s is out-of-date (hash mismatch). Type "
+          "information "
           "from this module may be incomplete or inconsistent with the rest of "
           "the program. Rebuilding the project will regenerate the needed "
           "module files.",
@@ -2083,7 +2082,7 @@
           }
         } else {
           GetObjectFile()->GetModule()->ReportWarning(
-              "0x%8.8x: compile unit %u failed to create a valid "
+              "0x%16.16" PRIx64 ": compile unit %u failed to create a valid "
               "lldb_private::CompileUnit class.",
               cu_offset, cu_idx);
         }
@@ -3026,7 +3025,7 @@
                 log,
                 "SymbolFileDWARF::"
                 "FindDefinitionTypeForDWARFDeclContext(tag=%s, "
-                "qualified-name='%s') ignoring die=0x%8.8x (%s)",
+                "qualified-name='%s') ignoring die=0x%16.16" PRIx64 " (%s)",
                 DW_TAG_value_to_name(dwarf_decl_ctx[0].tag),
                 dwarf_decl_ctx.GetQualifiedName(), type_die.GetOffset(),
                 type_die.GetName());
@@ -3041,7 +3040,7 @@
               log,
               "SymbolFileDWARF::"
               "FindDefinitionTypeForDWARFDeclContext(tag=%s, "
-              "qualified-name='%s') trying die=0x%8.8x (%s)",
+              "qualified-name='%s') trying die=0x%16.16" PRIx64 " (%s)",
               DW_TAG_value_to_name(dwarf_decl_ctx[0].tag),
               dwarf_decl_ctx.GetQualifiedName(), type_die.GetOffset(),
               type_dwarf_decl_ctx.GetQualifiedName());
@@ -3148,7 +3147,7 @@
     return 0;
 
   size_t functions_added = 0;
-  const dw_offset_t function_die_offset = func.GetID();
+  const dw_offset_t function_die_offset = DIERef(func.GetID()).die_offset();
   DWARFDIE function_die =
       dwarf_cu->GetNonSkeletonUnit().GetDIE(function_die_offset);
   if (function_die) {
@@ -3438,8 +3437,8 @@
         StreamString strm;
         location->DumpLocation(&strm, eDescriptionLevelFull, nullptr);
         GetObjectFile()->GetModule()->ReportError(
-            "0x%8.8x: %s has an invalid location: %s", die.GetOffset(),
-            die.GetTagAsCString(), strm.GetData());
+            "0x%16.16" PRIx64 ": %s has an invalid location: %s",
+            die.GetOffset(), die.GetTagAsCString(), strm.GetData());
       }
       if (location_DW_OP_addr != LLDB_INVALID_ADDRESS)
         is_static_lifetime = true;
@@ -4124,8 +4123,8 @@
           dwp_file_data_offset);
       if (!dwp_obj_file)
         return;
-      m_dwp_symfile =
-          std::make_shared<SymbolFileDWARFDwo>(*this, dwp_obj_file, 0x3fffffff);
+      m_dwp_symfile = std::make_shared<SymbolFileDWARFDwo>(
+          *this, dwp_obj_file, DIERef::k_dwo_num_mask);
     }
   });
   return m_dwp_symfile;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.h
@@ -9,6 +9,7 @@
 #ifndef LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_SYMBOLFILEDWARFDEBUGMAP_H
 #define LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_SYMBOLFILEDWARFDEBUGMAP_H
 
+#include "DIERef.h"
 #include "lldb/Symbol/SymbolFile.h"
 #include "lldb/Utility/RangeMap.h"
 #include "llvm/Support/Chrono.h"
@@ -208,7 +209,9 @@
   lldb::CompUnitSP ParseCompileUnitAtIndex(uint32_t index) override;
 
   static uint32_t GetOSOIndexFromUserID(lldb::user_id_t uid) {
-    return (uint32_t)((uid >> 32ull) - 1ull);
+    llvm::Optional<uint32_t> OsoNum = DIERef(uid).oso_num();
+    lldbassert(OsoNum && "Invalid OSO Index");
+    return *OsoNum;
   }
 
   static SymbolFileDWARF *GetSymbolFileAsSymbolFileDWARF(SymbolFile *sym_file);
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDebugMap.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "SymbolFileDWARFDebugMap.h"
+#include "DIERef.h"
 #include "DWARFCompileUnit.h"
 #include "DWARFDebugAranges.h"
 #include "DWARFDebugInfo.h"
@@ -210,7 +211,9 @@
             // Set the ID of the symbol file DWARF to the index of the OSO
             // shifted left by 32 bits to provide a unique prefix for any
             // UserID's that get created in the symbol file.
-            oso_symfile->SetID(((uint64_t)m_cu_idx + 1ull) << 32ull);
+            oso_symfile->SetID(DIERef(DIERef::IndexType::OSONum, m_cu_idx,
+                                      DIERef::Section(0), 0)
+                                   .get_id());
           }
           return symfile;
         }
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.h
@@ -9,6 +9,7 @@
 #ifndef LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_SYMBOLFILEDWARFDWO_H
 #define LLDB_SOURCE_PLUGINS_SYMBOLFILE_DWARF_SYMBOLFILEDWARFDWO_H
 
+#include "DIERef.h"
 #include "SymbolFileDWARF.h"
 
 class SymbolFileDWARFDwo : public SymbolFileDWARF {
@@ -40,7 +41,9 @@
   DWARFDIE
   GetDIE(const DIERef &die_ref) override;
 
-  llvm::Optional<uint32_t> GetDwoNum() override { return GetID() >> 32; }
+  llvm::Optional<uint32_t> GetDwoNum() override {
+    return DIERef(GetID()).dwo_num();
+  }
 
   lldb::offset_t
   GetVendorDWARFOpcodeSize(const lldb_private::DataExtractor &data,
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARFDwo.cpp
@@ -8,6 +8,7 @@
 
 #include "SymbolFileDWARFDwo.h"
 
+#include "DIERef.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Expression/DWARFExpression.h"
 #include "lldb/Symbol/ObjectFile.h"
@@ -28,7 +29,7 @@
     : SymbolFileDWARF(objfile, objfile->GetSectionList(
                                    /*update_module_section_list*/ false)),
       m_base_symbol_file(base_symbol_file) {
-  SetID(user_id_t(id) << 32);
+  SetID(DIERef(id, DIERef::Section(0), 0).get_id());
 
   // Parsing of the dwarf unit index is not thread-safe, so we need to prime it
   // to enable subsequent concurrent lookups.
diff --git a/lldb/source/Symbol/DWARFCallFrameInfo.cpp b/lldb/source/Symbol/DWARFCallFrameInfo.cpp
--- a/lldb/source/Symbol/DWARFCallFrameInfo.cpp
+++ b/lldb/source/Symbol/DWARFCallFrameInfo.cpp
@@ -773,7 +773,7 @@
           // function.)
           if (stack.empty()) {
             LLDB_LOGF(log,
-                      "DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx32
+                      "DWARFCallFrameInfo::%s(dwarf_offset: %" PRIx64
                       ", startaddr: %" PRIx64
                       " encountered DW_CFA_restore_state but state stack "
                       "is empty. Corrupt unwind info?",
diff --git a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_range-DW_FORM_sec_offset.s b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_range-DW_FORM_sec_offset.s
--- a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_range-DW_FORM_sec_offset.s
+++ b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_range-DW_FORM_sec_offset.s
@@ -8,7 +8,7 @@
 # RUN:   -o exit | FileCheck %s
 
 # Failure was the block range 1..2 was not printed plus:
-# error: DW_AT_range-DW_FORM_sec_offset.s.tmp {0x0000003f}: DIE has DW_AT_ranges(0xc) attribute, but range extraction failed (missing or invalid range list table), please file a bug and attach the file at the start of this error message
+# error: DW_AT_range-DW_FORM_sec_offset.s.tmp {0x000000000000003f}: DIE has DW_AT_ranges(0xc) attribute, but range extraction failed (missing or invalid range list table), please file a bug and attach the file at the start of this error message
 
 # CHECK-LABEL: image lookup -v -s lookup_rnglists
 # CHECK:  Function: id = {0x00000029}, name = "rnglists", range = [0x0000000000000000-0x0000000000000003)
@@ -22,7 +22,7 @@
 # RUN: cat %t.error | FileCheck --check-prefix=ERROR %s
 
 # RNGLISTX-LABEL: image lookup -v -s lookup_rnglists
-# ERROR: error: {{.*}} {0x0000003f}: DIE has DW_AT_ranges(DW_FORM_rnglistx 0x0) attribute, but range extraction failed (DW_FORM_rnglistx cannot be used without DW_AT_rnglists_base for CU at 0x00000000), please file a bug and attach the file at the start of this error message
+# ERROR: error: {{.*}} {0x000000000000003f}: DIE has DW_AT_ranges(DW_FORM_rnglistx 0x0) attribute, but range extraction failed (DW_FORM_rnglistx cannot be used without DW_AT_rnglists_base for CU at 0x00000000), please file a bug and attach the file at the start of this error message
 
 # RUN: llvm-mc -triple=x86_64-pc-linux -filetype=obj \
 # RUN:   --defsym RNGLISTX=0 --defsym RNGLISTBASE=0 %s > %t-rnglistbase
@@ -31,7 +31,7 @@
 # RUN: cat %t.error | FileCheck --check-prefix=ERRORBASE %s
 
 # RNGLISTBASE-LABEL: image lookup -v -s lookup_rnglists
-# ERRORBASE: error: {{.*}}-rnglistbase {0x00000043}: DIE has DW_AT_ranges(DW_FORM_rnglistx 0x0) attribute, but range extraction failed (invalid range list table index 0; OffsetEntryCount is 0, DW_AT_rnglists_base is 24), please file a bug and attach the file at the start of this error message
+# ERRORBASE: error: {{.*}}-rnglistbase {0x0000000000000043}: DIE has DW_AT_ranges(DW_FORM_rnglistx 0x0) attribute, but range extraction failed (invalid range list table index 0; OffsetEntryCount is 0, DW_AT_rnglists_base is 24), please file a bug and attach the file at the start of this error message
 
         .text
 rnglists:
diff --git a/lldb/test/Shell/SymbolFile/DWARF/x86/debug_rnglists-dwo.s b/lldb/test/Shell/SymbolFile/DWARF/x86/debug_rnglists-dwo.s
--- a/lldb/test/Shell/SymbolFile/DWARF/x86/debug_rnglists-dwo.s
+++ b/lldb/test/Shell/SymbolFile/DWARF/x86/debug_rnglists-dwo.s
@@ -4,9 +4,9 @@
 # RUN:   -o exit | FileCheck %s
 
 # CHECK-LABEL: image lookup -v -s lookup_rnglists
-# CHECK:  Function: id = {0x4000000000000028}, name = "rnglists", range = [0x0000000000000000-0x0000000000000003)
-# CHECK:    Blocks: id = {0x4000000000000028}, range = [0x00000000-0x00000003)
-# CHECK-NEXT:       id = {0x4000000000000037}, range = [0x00000001-0x00000002)
+# CHECK:  Function: id = {0x2000000000000028}, name = "rnglists", range = [0x0000000000000000-0x0000000000000003)
+# CHECK:    Blocks: id = {0x2000000000000028}, range = [0x00000000-0x00000003)
+# CHECK-NEXT:       id = {0x2000000000000037}, range = [0x00000001-0x00000002)
 
         .text
 rnglists:
diff --git a/lldb/unittests/SymbolFile/DWARF/DWARFIndexCachingTest.cpp b/lldb/unittests/SymbolFile/DWARF/DWARFIndexCachingTest.cpp
--- a/lldb/unittests/SymbolFile/DWARF/DWARFIndexCachingTest.cpp
+++ b/lldb/unittests/SymbolFile/DWARF/DWARFIndexCachingTest.cpp
@@ -45,6 +45,26 @@
   EncodeDecode(DIERef(200, DIERef::Section::DebugTypes, 0x11223344));
 }
 
+TEST(DWARFIndexCachingTest, DIERefEncodeDecodeMax) {
+  // Tests DIERef::Encode(...) and DIERef::Decode(...)
+  EncodeDecode(DIERef(llvm::None, DIERef::Section::DebugInfo,
+                      DIERef::k_die_offset_mask));
+  EncodeDecode(DIERef(llvm::None, DIERef::Section::DebugTypes,
+                      DIERef::k_die_offset_mask));
+  EncodeDecode(
+      DIERef(100, DIERef::Section::DebugInfo, DIERef::k_die_offset_mask));
+  EncodeDecode(
+      DIERef(200, DIERef::Section::DebugTypes, DIERef::k_die_offset_mask));
+  EncodeDecode(DIERef(DIERef::k_dwo_num_mask, DIERef::Section::DebugInfo,
+                      DIERef::k_dwo_num_mask));
+  EncodeDecode(DIERef(DIERef::k_dwo_num_mask, DIERef::Section::DebugTypes,
+                      DIERef::k_dwo_num_mask));
+  EncodeDecode(
+      DIERef(DIERef::k_dwo_num_mask, DIERef::Section::DebugInfo, 0x11223344));
+  EncodeDecode(
+      DIERef(DIERef::k_dwo_num_mask, DIERef::Section::DebugTypes, 0x11223344));
+}
+
 static void EncodeDecode(const NameToDIE &object, ByteOrder byte_order) {
   const uint8_t addr_size = 8;
   DataEncoder encoder(byte_order, addr_size);