[libclang] Introduce a new parsing option 'CXTranslationUnit_SingleFileParse' that puts preprocessor in a mode for parsing a single file only.

This is useful for parsing a single file, as a fast/inaccurate 'mode' that can still provide declarations from the file, like the classes and their methods.

llvm-svn: 305044

2 files changed, 7 insertions, 2 deletions

diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 3040517a9dd..bf856f01460 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -1982,7 +1982,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
     unsigned PrecompilePreambleAfterNParses, TranslationUnitKind TUKind,
     bool CacheCodeCompletionResults, bool IncludeBriefCommentsInCodeCompletion,
     bool AllowPCHWithCompilerErrors, bool SkipFunctionBodies,
-    bool UserFilesAreVolatile, bool ForSerialization,
+    bool SingleFileParse, bool UserFilesAreVolatile, bool ForSerialization,
     llvm::Optional<StringRef> ModuleFormat, std::unique_ptr<ASTUnit> *ErrAST,
     IntrusiveRefCntPtr<vfs::FileSystem> VFS) {
   assert(Diags.get() && "no DiagnosticsEngine was provided");
@@ -2011,6 +2011,7 @@ ASTUnit *ASTUnit::LoadFromCommandLine(
   PPOpts.RemappedFilesKeepOriginalName = RemappedFilesKeepOriginalName;
   PPOpts.AllowPCHWithCompilerErrors = AllowPCHWithCompilerErrors;
   PPOpts.GeneratePreamble = PrecompilePreambleAfterNParses != 0;
+  PPOpts.SingleFileParseMode = SingleFileParse;
   
   // Override the resources path.
   CI->getHeaderSearchOpts().ResourceDir = ResourceFilesPath;
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index b2c3c2e7076..89c2ebd00a6 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -30,6 +30,7 @@
 #include "clang/Lex/PPCallbacks.h"
 #include "clang/Lex/Pragma.h"
 #include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/PreprocessorOptions.h"
 #include "clang/Lex/PTHLexer.h"
 #include "clang/Lex/Token.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -1845,10 +1846,13 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
   // we've imported or already built.
   bool ShouldEnter = true;
 
+  if (PPOpts->SingleFileParseMode)
+    ShouldEnter = false;
+
   // Determine whether we should try to import the module for this #include, if
   // there is one. Don't do so if precompiled module support is disabled or we
   // are processing this module textually (because we're building the module).
-  if (File && SuggestedModule && getLangOpts().Modules &&
+  if (ShouldEnter && File && SuggestedModule && getLangOpts().Modules &&
       SuggestedModule.getModule()->getTopLevelModuleName() !=
           getLangOpts().CurrentModule) {
     // If this include corresponds to a module but that module is