3 files changed, 48 insertions, 3 deletions

diff --git a/tools/CIndex/CIndex.cpp b/tools/CIndex/CIndex.cpp
index a5b7e99622..8ef9fb5ca0 100644
--- a/tools/CIndex/CIndex.cpp
+++ b/tools/CIndex/CIndex.cpp
@@ -324,6 +324,11 @@ public:
     DisplayDiagnostics = Display;
   }
 
+  bool getUseExternalASTGeneration() const { return UseExternalASTGeneration; }
+  void setUseExternalASTGeneration(bool Value) {
+    UseExternalASTGeneration = Value;
+  }
+
   Diagnostic &getDiags() {
     return DisplayDiagnostics ? *TextDiags : IgnoreDiags;
   }
@@ -466,6 +471,12 @@ void clang_disposeIndex(CXIndex CIdx) {
   delete static_cast<CIndexer *>(CIdx);
 }
 
+void clang_setUseExternalASTGeneration(CXIndex CIdx, int value) {
+  assert(CIdx && "Passed null CXIndex");
+  CIndexer *CXXIdx = static_cast<CIndexer *>(CIdx);
+  CXXIdx->setUseExternalASTGeneration(value);
+}
+
 // FIXME: need to pass back error info.
 CXTranslationUnit clang_createTranslationUnit(CXIndex CIdx,
                                               const char *ast_filename) {
@@ -485,6 +496,24 @@ clang_createTranslationUnitFromSourceFile(CXIndex CIdx,
   assert(CIdx && "Passed null CXIndex");
   CIndexer *CXXIdx = static_cast<CIndexer *>(CIdx);
 
+  if (!CXXIdx->getUseExternalASTGeneration()) {
+    llvm::SmallVector<const char *, 16> Args;
+
+    // The 'source_filename' argument is optional.  If the caller does not
+    // specify it then it is assumed that the source file is specified
+    // in the actual argument list.
+    if (source_filename)
+      Args.push_back(source_filename);
+    Args.insert(Args.end(), command_line_args,
+                command_line_args + num_command_line_args);
+
+    void *MainAddr = (void *)(uintptr_t)clang_createTranslationUnit;
+    return ASTUnit::LoadFromCommandLine(Args.data(), Args.data() + Args.size(),
+                                        CXXIdx->getDiags(), "<clang>", MainAddr,
+                                        CXXIdx->getOnlyLocalDecls(),
+                                        /* UseBumpAllocator = */ true);
+  }
+
   // Build up the arguments for invoking 'clang'.
   std::vector<const char *> argv;
 
@@ -572,8 +601,18 @@ void clang_loadTranslationUnit(CXTranslationUnit CTUnit,
   ASTUnit *CXXUnit = static_cast<ASTUnit *>(CTUnit);
   ASTContext &Ctx = CXXUnit->getASTContext();
 
-  TUVisitor DVisit(CTUnit, callback, CData,
-                   CXXUnit->getOnlyLocalDecls()? 1 : Decl::MaxPCHLevel);
+  unsigned PCHLevel = Decl::MaxPCHLevel;
+
+  // Set the PCHLevel to filter out unwanted decls if requested.
+  if (CXXUnit->getOnlyLocalDecls()) {
+    PCHLevel = 0;
+
+    // If the main input was an AST, bump the level.
+    if (CXXUnit->isMainFileAST())
+      ++PCHLevel;
+  }
+
+  TUVisitor DVisit(CTUnit, callback, CData, PCHLevel);
   DVisit.Visit(Ctx.getTranslationUnitDecl());
 }
 
diff --git a/tools/CIndex/CIndex.exports b/tools/CIndex/CIndex.exports
index 2892ce50e7..458ad10283 100644
--- a/tools/CIndex/CIndex.exports
+++ b/tools/CIndex/CIndex.exports
@@ -6,6 +6,7 @@ _clang_disposeIndex
 _clang_disposeString
 _clang_disposeTranslationUnit
 _clang_equalCursors
+_clang_getCString
 _clang_getCompletionChunkCompletionString
 _clang_getCompletionChunkKind
 _clang_getCompletionChunkText
@@ -19,7 +20,6 @@ _clang_getCursorLine
 _clang_getCursorSource
 _clang_getCursorSourceFile
 _clang_getCursorSpelling
-_clang_getCString
 _clang_getDeclColumn
 _clang_getDeclLine
 _clang_getDeclSource
@@ -41,3 +41,4 @@ _clang_isInvalid
 _clang_isReference
 _clang_loadDeclaration
 _clang_loadTranslationUnit
+_clang_setUseExternalASTGeneration
diff --git a/tools/c-index-test/c-index-test.c b/tools/c-index-test/c-index-test.c
index efff1ae318..7300585a1d 100644
--- a/tools/c-index-test/c-index-test.c
+++ b/tools/c-index-test/c-index-test.c
@@ -179,12 +179,17 @@ int perform_test_load_tu(const char *file, const char *filter) {
 }
 
 int perform_test_load_source(int argc, const char **argv, const char *filter) {
+  const char *UseExternalASTs =
+    getenv("CINDEXTEST_USE_EXTERNAL_AST_GENERATION");
   CXIndex Idx;
   CXTranslationUnit TU;
   Idx = clang_createIndex(/* excludeDeclsFromPCH */
                           !strcmp(filter, "local") ? 1 : 0,
                           /* displayDiagnostics */ 1);
 
+  if (UseExternalASTs && strlen(UseExternalASTs))
+    clang_setUseExternalASTGeneration(Idx, 1);
+
   TU = clang_createTranslationUnitFromSourceFile(Idx, 0, argc, argv);
   if (!TU) {
     fprintf(stderr, "Unable to load translation unit!\n");