[clang-tidy] Make NumOccurrenceFlag for SourcePaths configurable.

Added an additional ctor that takes a NumOccurrenceFlag parameter for the
SourcePaths option. This frees applications from always having to pass at least
one source file, e.g., -list-checks.

http://reviews.llvm.org/D12069

Patch by Don Hinton!

llvm-svn: 245204

2 files changed, 24 insertions, 4 deletions

diff --git a/clang/include/clang/Tooling/CommonOptionsParser.h b/clang/include/clang/Tooling/CommonOptionsParser.h
index c23dc9211dc..65d62a3f3cf 100644
--- a/clang/include/clang/Tooling/CommonOptionsParser.h
+++ b/clang/include/clang/Tooling/CommonOptionsParser.h
@@ -72,6 +72,23 @@ public:
   /// This constructor exits program in case of error.
   CommonOptionsParser(int &argc, const char **argv,
                       llvm::cl::OptionCategory &Category,
+                      const char *Overview = nullptr)
+      : CommonOptionsParser(argc, argv, Category, llvm::cl::OneOrMore,
+                            Overview) {}
+
+  /// \brief Parses command-line, initializes a compilation database.
+  ///
+  /// This constructor can change argc and argv contents, e.g. consume
+  /// command-line options used for creating FixedCompilationDatabase.
+  ///
+  /// All options not belonging to \p Category become hidden.
+  ///
+  /// I also allows calls to set the required number of positional parameters.
+  ///
+  /// This constructor exits program in case of error.
+  CommonOptionsParser(int &argc, const char **argv,
+                      llvm::cl::OptionCategory &Category,
+                      llvm::cl::NumOccurrencesFlag OccurrencesFlag,
                       const char *Overview = nullptr);
 
   /// Returns a reference to the loaded compilations database.
diff --git a/clang/lib/Tooling/CommonOptionsParser.cpp b/clang/lib/Tooling/CommonOptionsParser.cpp
index adae1781f45..289874bfd8a 100644
--- a/clang/lib/Tooling/CommonOptionsParser.cpp
+++ b/clang/lib/Tooling/CommonOptionsParser.cpp
@@ -92,16 +92,16 @@ private:
 };
 } // namespace
 
-CommonOptionsParser::CommonOptionsParser(int &argc, const char **argv,
-                                         cl::OptionCategory &Category,
-                                         const char *Overview) {
+CommonOptionsParser::CommonOptionsParser(
+    int &argc, const char **argv, cl::OptionCategory &Category,
+    llvm::cl::NumOccurrencesFlag OccurrencesFlag, const char *Overview) {
   static cl::opt<bool> Help("h", cl::desc("Alias for -help"), cl::Hidden);
 
   static cl::opt<std::string> BuildPath("p", cl::desc("Build path"),
                                         cl::Optional, cl::cat(Category));
 
   static cl::list<std::string> SourcePaths(
-      cl::Positional, cl::desc("<source0> [... <sourceN>]"), cl::OneOrMore,
+      cl::Positional, cl::desc("<source0> [... <sourceN>]"), OccurrencesFlag,
       cl::cat(Category));
 
   static cl::list<std::string> ArgsAfter(
@@ -120,6 +120,9 @@ CommonOptionsParser::CommonOptionsParser(int &argc, const char **argv,
                                                                    argv));
   cl::ParseCommandLineOptions(argc, argv, Overview);
   SourcePathList = SourcePaths;
+  if ((OccurrencesFlag == cl::ZeroOrMore || OccurrencesFlag == cl::Optional) &&
+      SourcePathList.empty())
+    return;
   if (!Compilations) {
     std::string ErrorMessage;
     if (!BuildPath.empty()) {