Index: lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
+++ lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
@@ -90,6 +90,7 @@
 
   bool IsDWOUnit() { return m_is_dwo; }
   uint64_t GetDWOId();
+  uint64_t GetDWOIdIfAlreadyParsed() const { return m_dwo_id; }
 
   void ExtractUnitDIEIfNeeded();
   void ExtractUnitDIENoDwoIfNeeded();
Index: lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
+++ lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.h
@@ -22,7 +22,8 @@
   ManualDWARFIndex(Module &module, SymbolFileDWARF &dwarf,
                    llvm::DenseSet<dw_offset_t> units_to_avoid = {})
       : DWARFIndex(module), m_dwarf(&dwarf),
-        m_units_to_avoid(std::move(units_to_avoid)) {}
+        m_units_to_avoid(std::move(units_to_avoid)),
+        m_has_indexed_type_units(false) {}
 
   void Preload() override { Index(); }
 
@@ -67,6 +68,7 @@
     NameToDIE namespaces;
   };
   void Index();
+  void IndexImpl(bool full_index, uint64_t unit_dwo_id);
   void IndexUnit(DWARFUnit &unit, SymbolFileDWARFDwo *dwp, IndexSet &set);
 
   static void IndexUnitImpl(DWARFUnit &unit,
@@ -78,6 +80,8 @@
   SymbolFileDWARF *m_dwarf;
   /// Which dwarf units should we skip while building the index.
   llvm::DenseSet<dw_offset_t> m_units_to_avoid;
+  llvm::DenseSet<size_t> m_ids_already_indexed;
+  bool m_has_indexed_type_units;
 
   IndexSet m_set;
 };
Index: lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
+++ lldb/source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp
@@ -24,11 +24,17 @@
 using namespace lldb;
 
 void ManualDWARFIndex::Index() {
+  IndexImpl(true, 0);
+}
+
+void ManualDWARFIndex::IndexImpl(bool full_index, uint64_t unit_dwo_id) {
   if (!m_dwarf)
     return;
 
   SymbolFileDWARF &main_dwarf = *m_dwarf;
-  m_dwarf = nullptr;
+
+  if (full_index)
+    m_dwarf = nullptr;
 
   LLDB_SCOPED_TIMERF("%p", static_cast<void *>(&main_dwarf));
 
@@ -45,16 +51,25 @@
   // IndexUnit.
   for (size_t U = 0; U < main_info.GetNumUnits(); ++U) {
     DWARFUnit *unit = main_info.GetUnitAtIndex(U);
-    if (unit && m_units_to_avoid.count(unit->GetOffset()) == 0)
-      units_to_index.push_back(unit);
+    if (unit && m_units_to_avoid.count(unit->GetOffset()) == 0 && m_ids_already_indexed.count(unit->GetDWOId()) == 0) {
+      if (full_index || unit->GetDWOId() == unit_dwo_id)
+        units_to_index.push_back(unit);
+    }
   }
-  if (dwp_info && dwp_info->ContainsTypeUnits()) {
+  if (!full_index && !units_to_index.empty())
+    m_ids_already_indexed.insert(unit_dwo_id);  // Don't index this again
+  if (!m_has_indexed_type_units && dwp_info && dwp_info->ContainsTypeUnits()) {
+    m_has_indexed_type_units = true;
     for (size_t U = 0; U < dwp_info->GetNumUnits(); ++U) {
       if (auto *tu = llvm::dyn_cast<DWARFTypeUnit>(dwp_info->GetUnitAtIndex(U)))
         units_to_index.push_back(tu);
     }
   }
 
+  // We no longer need this; clear to save memory
+  if (full_index)
+    m_ids_already_indexed.clear();
+
   if (units_to_index.empty())
     return;
 
@@ -359,7 +374,7 @@
 
 void ManualDWARFIndex::GetGlobalVariables(
     const DWARFUnit &unit, llvm::function_ref<bool(DWARFDIE die)> callback) {
-  Index();
+  IndexImpl(false, unit.GetDWOIdIfAlreadyParsed());
   m_set.globals.FindAllEntriesForUnit(unit, DIERefCallback(callback));
 }
 
Index: lldb/test/Shell/SymbolFile/DWARF/dwp-debug-types.s
===================================================================
--- lldb/test/Shell/SymbolFile/DWARF/dwp-debug-types.s
+++ lldb/test/Shell/SymbolFile/DWARF/dwp-debug-types.s
@@ -16,15 +16,15 @@
 
 # Make sure each entity is present in the index only once.
 # SYMBOLS:      Globals and statics:
-# SYMBOLS-DAG: INFO/00000023 "A"
-# SYMBOLS-DAG: INFO/0000005a "A"
+# SYMBOLS-DAG: INFO/0000002b "A"
+# SYMBOLS-DAG: INFO/0000006a "A"
 # SYMBOLS-EMPTY:
 
 # SYMBOLS: Types:
 # SYMBOLS-DAG: TYPE/00000018 "ENUM0"
-# SYMBOLS-DAG: TYPE/0000004d "ENUM1"
 # SYMBOLS-DAG: TYPE/0000002d "int"
 # SYMBOLS-DAG: TYPE/00000062 "int"
+# SYMBOLS-DAG: TYPE/0000004d "ENUM1"
 # SYMBOLS-EMPTY:
 
 .ifdef MAIN
@@ -77,6 +77,8 @@
         .byte   8                       # DW_FORM_string
         .byte   3                       # DW_AT_name
         .byte   8                       # DW_FORM_string
+        .ascii  "\261B"                 # DW_AT_GNU_dwo_id
+        .byte   7                       # DW_FORM_data8
         .byte   0                       # EOM(1)
         .byte   0                       # EOM(2)
         .byte   \I*10+2                 # Abbreviation Code
@@ -148,6 +150,7 @@
         .byte   \I*10+1                 # Abbrev DW_TAG_compile_unit
         .asciz  "Hand-written DWARF"    # DW_AT_producer
         .byte   '0'+\I, '.', 'c', 0     # DW_AT_name
+        .quad   \I                      # DW_AT_GNU_dwo_id
         .byte   \I*10+2                 # Abbrev DW_TAG_variable
         .asciz  "A"                     # DW_AT_name
         .long   .Lenum_ref\I-.Lcu_begin\I# DW_AT_type
Index: lldb/test/Shell/SymbolFile/DWARF/dwp.s
===================================================================
--- lldb/test/Shell/SymbolFile/DWARF/dwp.s
+++ lldb/test/Shell/SymbolFile/DWARF/dwp.s
@@ -133,6 +133,8 @@
         .byte   8                       # DW_FORM_string
         .byte   3                       # DW_AT_name
         .byte   8                       # DW_FORM_string
+        .ascii  "\261B"                 # DW_AT_GNU_dwo_id
+        .byte   7                       # DW_FORM_data8
         .byte   0                       # EOM(1)
         .byte   0                       # EOM(2)
         .byte   \I*10+2                 # Abbreviation Code
@@ -201,6 +203,7 @@
         .byte   \I*10+1                 # Abbrev DW_TAG_compile_unit
         .asciz  "Hand-written DWARF"    # DW_AT_producer
         .byte   '0'+\I, '.', 'c', 0     # DW_AT_name
+        .quad   \I                      # DW_AT_GNU_dwo_id
         .byte   \I*10+2                 # Abbrev DW_TAG_variable
         .asciz  "A"                     # DW_AT_name
         .long   .Ltypedef\I-.Lcu_begin\I# DW_AT_type