From 87f9d81d0ab806dcf6ca50a0c068dcb2ba7f51b3 Mon Sep 17 00:00:00 2001
From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Wed, 17 Apr 2013 22:10:55 +0000
Subject: [PATCH] [Modules] Use global index to improve typo correction
 performance

Typo correction for an unqualified name needs to walk through all of the identifier tables of all modules.
When we have a global index, just walk its identifier table only.

rdar://13425732

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179730 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/IdentifierTable.h         |  2 +-
 include/clang/Serialization/ASTReader.h       |  2 +-
 .../clang/Serialization/GlobalModuleIndex.h   |  5 +++
 lib/Basic/IdentifierTable.cpp                 |  2 +-
 lib/Serialization/ASTReader.cpp               |  5 ++-
 lib/Serialization/GlobalModuleIndex.cpp       | 31 +++++++++++++++++++
 6 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/include/clang/Basic/IdentifierTable.h b/include/clang/Basic/IdentifierTable.h
index c04a893c6f..d4d53390bd 100644
--- a/include/clang/Basic/IdentifierTable.h
+++ b/include/clang/Basic/IdentifierTable.h
@@ -394,7 +394,7 @@ public:
   ///
   /// \returns A new iterator into the set of known identifiers. The
   /// caller is responsible for deleting this iterator.
-  virtual IdentifierIterator *getIdentifiers() const;
+  virtual IdentifierIterator *getIdentifiers();
 };
 
 /// \brief An abstract class used to resolve numerical identifier
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index 925533678c..a773e41667 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -1558,7 +1558,7 @@ public:
 
   /// \brief Retrieve an iterator into the set of all identifiers
   /// in all loaded AST files.
-  virtual IdentifierIterator *getIdentifiers() const;
+  virtual IdentifierIterator *getIdentifiers();
 
   /// \brief Load the contents of the global method pool for a given
   /// selector.
diff --git a/include/clang/Serialization/GlobalModuleIndex.h b/include/clang/Serialization/GlobalModuleIndex.h
index eaf26d1df1..ab91f4009c 100644
--- a/include/clang/Serialization/GlobalModuleIndex.h
+++ b/include/clang/Serialization/GlobalModuleIndex.h
@@ -146,6 +146,11 @@ public:
   static std::pair<GlobalModuleIndex *, ErrorCode>
   readIndex(StringRef Path);
 
+  /// \brief Returns an iterator for identifiers stored in the index table.
+  ///
+  /// The caller accepts ownership of the returned object.
+  IdentifierIterator *createIdentifierIterator() const;
+
   /// \brief Retrieve the set of modules that have up-to-date indexes.
   ///
   /// \param ModuleFiles Will be populated with the set of module files that
diff --git a/lib/Basic/IdentifierTable.cpp b/lib/Basic/IdentifierTable.cpp
index 429d9d8cb2..951c718d18 100644
--- a/lib/Basic/IdentifierTable.cpp
+++ b/lib/Basic/IdentifierTable.cpp
@@ -65,7 +65,7 @@ namespace {
   };
 }
 
-IdentifierIterator *IdentifierInfoLookup::getIdentifiers() const {
+IdentifierIterator *IdentifierInfoLookup::getIdentifiers() {
   return new EmptyLookupIterator();
 }
 
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 9893823a12..5123b79d2e 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -6109,7 +6109,10 @@ StringRef ASTIdentifierIterator::Next() {
   return Result;
 }
 
-IdentifierIterator *ASTReader::getIdentifiers() const {
+IdentifierIterator *ASTReader::getIdentifiers() {
+  if (!loadGlobalIndex())
+    return GlobalIndex->createIdentifierIterator();
+
   return new ASTIdentifierIterator(*this);
 }
 
diff --git a/lib/Serialization/GlobalModuleIndex.cpp b/lib/Serialization/GlobalModuleIndex.cpp
index f9acb84728..b6693e40e5 100644
--- a/lib/Serialization/GlobalModuleIndex.cpp
+++ b/lib/Serialization/GlobalModuleIndex.cpp
@@ -818,3 +818,34 @@ GlobalModuleIndex::writeIndex(FileManager &FileMgr, StringRef Path) {
   // We're done.
   return EC_None;
 }
+
+namespace {
+  class GlobalIndexIdentifierIterator : public IdentifierIterator {
+    /// \brief The current position within the identifier lookup table.
+    IdentifierIndexTable::key_iterator Current;
+
+    /// \brief The end position within the identifier lookup table.
+    IdentifierIndexTable::key_iterator End;
+
+  public:
+    explicit GlobalIndexIdentifierIterator(IdentifierIndexTable &Idx) {
+      Current = Idx.key_begin();
+      End = Idx.key_end();
+    }
+
+    virtual StringRef Next() {
+      if (Current == End)
+        return StringRef();
+
+      StringRef Result = *Current;
+      ++Current;
+      return Result;
+    }
+  };
+}
+
+IdentifierIterator *GlobalModuleIndex::createIdentifierIterator() const {
+  IdentifierIndexTable &Table =
+    *static_cast<IdentifierIndexTable *>(IdentifierIndex);
+  return new GlobalIndexIdentifierIterator(Table);
+}
-- 
2.40.0