Adding a new cl::HideUnrelatedOptions API to allow clang to migrate off cl::getRegisteredOptions.

[beanz]

Summary

cl::getRegisteredOptions really exposes some of the innards of how command line parsing is implemented. Exposing new APIs that allow us to disentangle client code from implementation details will allow us to make more extensive changes to command line parsing.

[dexonsmith]

Testcase?

LGTM once you add one, with a style nit below.

[beanz]

Updates based on Duncan's feedback.

• Using C++ range-based for loop
• Added a unit test case

[dexonsmith]

LGTM.

[beanz]

Marking revision as accepted based on the LGTM from Duncan.

Thanks, will land shortly.

include/llvm/Support/CommandLine.h

 /// \param [in,out] Argv Command line into which to expand response files.
 /// \param [in] MarkEOLs Mark end of lines and the end of the response file
 /// with nullptrs in the Argv vector.
 /// \return true if all @files were expanded successfully or there were none.
 bool ExpandResponseFiles(StringSaver &Saver, TokenizerCallback Tokenizer,
                          SmallVectorImpl<const char *> &Argv,
                          bool MarkEOLs = false);
 
+/// \brief Mark all options not part of this category as cl::ReallyHidden.
+///
+/// \param Category the category of options to keep displaying
+///
+/// Some tools (like clang-format) like to be able to hide all options that are
+/// not specific to the tool. This function allows a tool to specify a single
+/// option category to display in the -help output.
+void HideUnrelatedOptions(cl::OptionCategory &Category);
+
 } // End namespace cl
 
 } // End namespace llvm
 
 #endif

lib/Support/CommandLine.cpp

if (!ExtraVersionPrinters)
     ExtraVersionPrinters = new std::vector<void (*)()>;
 
   ExtraVersionPrinters->push_back(func);
 }
 
 void cl::getRegisteredOptions(StringMap<Option *> &Map) {
   // Get all the options.
   SmallVector<Option *, 4> PositionalOpts; // NOT USED
-  SmallVector<Option *, 4> SinkOpts; // NOT USED
+  SmallVector<Option *, 4> SinkOpts;       // NOT USED
   assert(Map.size() == 0 && "StringMap must be empty");
   GetOptionInfo(PositionalOpts, SinkOpts, Map);
   return;
 }
 
+void cl::HideUnrelatedOptions(cl::OptionCategory &Category) {
+  StringMap<cl::Option *> Options;
+  cl::getRegisteredOptions(Options);
+  for (StringMap<cl::Option *>::iterator I = Options.begin(), E = Options.end();
+       I != E; ++I) {
+    if (I->second->Category != &Category && I->first() != "help" &&
+        I->first() != "version")
+      I->second->setHiddenFlag(cl::ReallyHidden);
+  }
+}
+
 void LLVMParseCommandLineOptions(int argc, const char *const *argv,
                                  const char *Overview) {
   llvm::cl::ParseCommandLineOptions(argc, argv, Overview);
 }