1 files changed, 49 insertions, 12 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index aa672b3a7ec..e33cccbd95c 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -7014,19 +7014,20 @@ namespace clang {
     /// the current AST file.
     ASTIdentifierLookupTable::key_iterator End;
 
+    /// \brief Whether to skip any modules in the ASTReader.
+    bool SkipModules;
+
   public:
-    explicit ASTIdentifierIterator(const ASTReader &Reader);
+    explicit ASTIdentifierIterator(const ASTReader &Reader,
+                                   bool SkipModules = false);
 
     StringRef Next() override;
   };
 }
 
-ASTIdentifierIterator::ASTIdentifierIterator(const ASTReader &Reader)
-  : Reader(Reader), Index(Reader.ModuleMgr.size() - 1) {
-  ASTIdentifierLookupTable *IdTable
-    = (ASTIdentifierLookupTable *)Reader.ModuleMgr[Index].IdentifierLookupTable;
-  Current = IdTable->key_begin();
-  End = IdTable->key_end();
+ASTIdentifierIterator::ASTIdentifierIterator(const ASTReader &Reader,
+                                             bool SkipModules)
+    : Reader(Reader), Index(Reader.ModuleMgr.size()), SkipModules(SkipModules) {
 }
 
 StringRef ASTIdentifierIterator::Next() {
@@ -7036,9 +7037,12 @@ StringRef ASTIdentifierIterator::Next() {
       return StringRef();
 
     --Index;
-    ASTIdentifierLookupTable *IdTable
-      = (ASTIdentifierLookupTable *)Reader.ModuleMgr[Index].
-        IdentifierLookupTable;
+    ModuleFile &F = Reader.ModuleMgr[Index];
+    if (SkipModules && F.isModule())
+      continue;
+
+    ASTIdentifierLookupTable *IdTable =
+        (ASTIdentifierLookupTable *)F.IdentifierLookupTable;
     Current = IdTable->key_begin();
     End = IdTable->key_end();
   }
@@ -7050,9 +7054,42 @@ StringRef ASTIdentifierIterator::Next() {
   return Result;
 }
 
+namespace {
+/// A utility for appending two IdentifierIterators.
+class ChainedIdentifierIterator : public IdentifierIterator {
+  std::unique_ptr<IdentifierIterator> Current;
+  std::unique_ptr<IdentifierIterator> Queued;
+
+public:
+  ChainedIdentifierIterator(std::unique_ptr<IdentifierIterator> First,
+                            std::unique_ptr<IdentifierIterator> Second)
+      : Current(std::move(First)), Queued(std::move(Second)) {}
+
+  StringRef Next() override {
+    if (!Current)
+      return StringRef();
+
+    StringRef result = Current->Next();
+    if (!result.empty())
+      return result;
+
+    // Try the queued iterator, which may itself be empty.
+    Current.reset();
+    std::swap(Current, Queued);
+    return Next();
+  }
+};
+} // end anonymous namespace.
+
 IdentifierIterator *ASTReader::getIdentifiers() {
-  if (!loadGlobalIndex())
-    return GlobalIndex->createIdentifierIterator();
+  if (!loadGlobalIndex()) {
+    std::unique_ptr<IdentifierIterator> ReaderIter(
+        new ASTIdentifierIterator(*this, /*SkipModules=*/true));
+    std::unique_ptr<IdentifierIterator> ModulesIter(
+        GlobalIndex->createIdentifierIterator());
+    return new ChainedIdentifierIterator(std::move(ReaderIter),
+                                         std::move(ModulesIter));
+  }
 
   return new ASTIdentifierIterator(*this);
 }