Add a hook to supply a custom CompilationDatabase. To add a custom CompilationDatabase, make it implement findCompilationDatabaseForDirectory in CustomCompilationDatabase.h and set USE_COSTUM_COMPILATION_DATABASE.

Differential Revision: http://llvm-reviews.chandlerc.com/D4

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@160061 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Tooling/CompilationDatabase.cpp b/lib/Tooling/CompilationDatabase.cpp
index a06343d..d54a5e7 100644
--- a/lib/Tooling/CompilationDatabase.cpp
+++ b/lib/Tooling/CompilationDatabase.cpp
@@ -18,6 +18,10 @@
 #include "llvm/Support/Path.h"
 #include "llvm/Support/system_error.h"
 
+#ifdef USE_CUSTOM_COMPILATION_DATABASE
+#include "CustomCompilationDatabase.h"
+#endif
+
 namespace clang {
 namespace tooling {
 
@@ -124,6 +128,11 @@
 
 static CompilationDatabase *
 findCompilationDatabaseFromDirectory(StringRef Directory) {
+#ifdef USE_CUSTOM_COMPILATION_DATABASE
+  if (CompilationDatabase *DB =
+      ::findCompilationDatabaseForDirectory(Directory))
+    return DB;
+#endif
   while (!Directory.empty()) {
     std::string LoadErrorMessage;