[CommandLine] Don't allow duplicate categories.

[hintonda]

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.

[MaskRay]

llvm/lib/Support/CommandLine.cpp

453

Doesn't plain find work?

[hintonda]

llvm/lib/Support/CommandLine.cpp

453

Ah, thanks for catching that. It's cruft from a previous iteration where I was excluding index 0, but realized I didn't need to. I'll fix, thanks...

[hintonda]

• Used find instead of find_if.

[hintonda]

• Remove file erroneously included in last upload.

llvm/examples/CMakeLists.txt

 add_subdirectory(BrainF)
+add_subdirectory(CommandLine)
 add_subdirectory(Fibonacci)
 add_subdirectory(HowToUseJIT)
 add_subdirectory(Kaleidoscope)
 add_subdirectory(ModuleMaker)
 
 if(LLVM_ENABLE_EH AND (NOT WIN32) AND (NOT "${LLVM_NATIVE_ARCH}" STREQUAL "ARM"))
     add_subdirectory(ExceptionDemo)
 endif()
 
 if( HAVE_PTHREAD_H )
   add_subdirectory(ParallelJIT)
 endif( HAVE_PTHREAD_H )

llvm/lib/Support/CommandLine.cpp

 
 void Option::addCategory(OptionCategory &C) {
   assert(!Categories.empty() && "Categories cannot be empty.");
   // Maintain backward compatibility by replacing the default GeneralCategory
   // if it's still set.  Otherwise, just add the new one.  The GeneralCategory
   // 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);
 }
 
 void Option::reset() {
   NumOccurrences = 0;
   setDefault();
   if (isDefaultOption())
     removeArgument();

llvm/unittests/Support/CommandLineTest.cpp

ASSERT_NE(TestOption2.Categories.end(),
                          [&](const llvm::cl::OptionCategory *Cat) {
                            return Cat == &TestCategory;
                          }))
       << "Failed to assign Option Category.";
 }
 
 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) {
                            return Cat == &TestCategory;
                          }))
       << "Failed to assign Option Category.";
   ASSERT_NE(TestOption2.Categories.end(),
             find_if(TestOption2.Categories,