[Support][CommandLine] Add cl::getRegisteredSubcommands()

This should allow users of the library to get a range to iterate through
all the subcommands that are registered to the global parser. This
allows users to define subcommands in libraries that self-register to
have dispatch done at a different stage (like main). It allows for
writing code like the following:

    for (auto *S : cl::getRegisteredSubcommands()) {
      if (*S) {
	// Dispatch on S->getName().
      }
    }

This change also contains tests that show this usage pattern.

Reviewers: zturner, dblaikie, echristo

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D24489

llvm-svn: 283296

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index c5ca2149de3..76bf45e8f51 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -309,6 +309,12 @@ public:
     RegisteredSubCommands.erase(sub);
   }
 
+  iterator_range<typename SmallPtrSet<SubCommand *, 4>::iterator>
+  getRegisteredSubcommands() {
+    return make_range(RegisteredSubCommands.begin(),
+                      RegisteredSubCommands.end());
+  }
+
   void reset() {
     ActiveSubCommand = nullptr;
     ProgramName.clear();
@@ -2107,6 +2113,11 @@ StringMap<Option *> &cl::getRegisteredOptions(SubCommand &Sub) {
   return Sub.OptionsMap;
 }
 
+iterator_range<typename SmallPtrSet<SubCommand *, 4>::iterator>
+cl::getRegisteredSubcommands() {
+  return GlobalParser->getRegisteredSubcommands();
+}
+
 void cl::HideUnrelatedOptions(cl::OptionCategory &Category, SubCommand &Sub) {
   for (auto &I : Sub.OptionsMap) {
     if (I.second->Category != &Category &&