Add API to run Clang internally

Use the Clang Driver API to construct an invocation of Clang like the
main "clang" compiler tool would for syntax-only or preprocess-only
actions.  Add two front-end actions, one for the '-E' preprocess-only
option and one for our syntax-only AST traversal.  Implement a
syntax-only action that falls back to the Clang syntax-only action
unless xml output is requested.  Leave xml output unimplemented for now.

Capture the '-o <output-file>' option ourselves since the Clang Driver
API will ignore it when using a syntax-only action.  Forward it to the
compiler invocation frontend options just before constructing the
frontend action implementation.

When '--castxml-cc-<id>' is given tell the driver to suppress its own
standard include path detection.  Give the driver options to configure
it to match the detected target triple and header search path.  Tell
it to suppress its builtin definitions.  Hook in to the front-end
action for each input source file to put the detected predefines into
the preprocessor configuration.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/Options.h b/src/Options.h
index 84c1fa6..58ba3b5 100644
--- a/src/Options.h
+++ b/src/Options.h
@@ -22,9 +22,11 @@
 
 struct Options
 {
-  Options(): GccXml(false), HaveCC(false) {}
+  Options(): PPOnly(false), GccXml(false), HaveCC(false) {}
+  bool PPOnly;
   bool GccXml;
   bool HaveCC;
+  std::string OutputFile;
   std::vector<std::string> Includes;
   std::string Predefines;
   std::string Triple;