[CommandLine] Don't allow duplicate categories.

Summary:
This is a fix to D61574, r360179, that allowed duplicate
OptionCategory's.  This change adds a check to make sure a category can
only be added once even if the user passes it twice.

Reviewed By: MaskRay

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61972

llvm-svn: 360913

llvm/lib/Support/CommandLine.cpp

@@ -450,7 +450,7 @@ void Option::addCategory(OptionCategory &C) {
   // must be explicitly added if you want multiple categories that include it.
   if (&C != &GeneralCategory && Categories[0] == &GeneralCategory)
     Categories[0] = &C;
-  else
+  else if (find(Categories, &C) == Categories.end())
     Categories.push_back(&C);
 }
 

llvm/unittests/Support/CommandLineTest.cpp

@@ -170,8 +170,12 @@ TEST(CommandLineTest, UseOptionCategory) {
 
 TEST(CommandLineTest, UseMultipleCategories) {
   StackOption<int> TestOption2("test-option2", cl::cat(TestCategory),
+                               cl::cat(cl::GeneralCategory),
                                cl::cat(cl::GeneralCategory));
 
+  // Make sure cl::GeneralCategory wasn't added twice.
+  ASSERT_EQ(TestOption2.Categories.size(), 2U);
+
   ASSERT_NE(TestOption2.Categories.end(),
             find_if(TestOption2.Categories,
                          [&](const llvm::cl::OptionCategory *Cat) {