[llvm-profdata] Fix llvm-profdata help and make sure it remains in sync

[serge-sans-paille]

Summary

This makes the new order subcommand part of the help.
As a side effect, also make llvm::map_range compatible with plain arrays.

[ellis]

Ah, thanks for catching the missing command in the help message. LGTM!

llvm/include/llvm/ADT/STLExtras.h

 // make_pair is useful for creating pairs...
 template <class ItTy, class FuncTy>
 inline mapped_iterator<ItTy, FuncTy> map_iterator(ItTy I, FuncTy F) {
   return mapped_iterator<ItTy, FuncTy>(std::move(I), std::move(F));
 }
 
 template <class ContainerTy, class FuncTy>
 auto map_range(ContainerTy &&C, FuncTy F) {
-  return make_range(map_iterator(C.begin(), F), map_iterator(C.end(), F));
+  return make_range(map_iterator(std::begin(C), F),
+                    map_iterator(std::end(C), F));
 }
 
 /// A base type of mapped iterator, that is useful for building derived
 /// iterators that do not need/want to store the map function (as in
 /// mapped_iterator). These iterators must simply provide a `mapElement` method
 /// that defines how to map a value of the iterator to the provided reference
 /// type.
 template <typename DerivedT, typename ItTy, typename ReferenceTy>

llvm/tools/llvm-profdata/llvm-profdata.cpp

if (FuncName.contains(':')) {
       OS << "# " << Filename << "\n";
       FuncName = ParsedFuncName;
     }
     OS << FuncName << "\n";
   }
   return 0;
 }
 
+typedef int (*llvm_profdata_subcommand)(int, const char *[]);
+
+static std::tuple<StringRef, llvm_profdata_subcommand>
+    llvm_profdata_subcommands[] = {
+        {"merge", merge_main},
+        {"show", show_main},
+        {"order", order_main},
+        {"overlap", overlap_main},
+};
+
 int llvm_profdata_main(int argc, char **argvNonConst,
                        const llvm::ToolContext &) {
   const char **argv = const_cast<const char **>(argvNonConst);
   InitLLVM X(argc, argv);
 
   StringRef ProgName(sys::path::filename(argv[0]));
   if (argc > 1) {
-    int (*func)(int, const char *[]) = nullptr;
 
-    if (strcmp(argv[1], "merge") == 0)
-      func = merge_main;
-    else if (strcmp(argv[1], "show") == 0)
-      func = show_main;
-    else if (strcmp(argv[1], "overlap") == 0)
-      func = overlap_main;
-    else if (strcmp(argv[1], "order") == 0)
-      func = order_main;
+    llvm_profdata_subcommand func = nullptr;
+    for (auto [subcmd_name, subcmd_action] : llvm_profdata_subcommands)
+      if (subcmd_name == argv[1])
+        func = subcmd_action;
 
     if (func) {
       std::string Invocation(ProgName.str() + " " + argv[1]);
       argv[1] = Invocation.c_str();
       return func(argc - 1, argv + 1);
     }
 
     if (strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "-help") == 0 ||
         strcmp(argv[1], "--help") == 0) {
 
       errs() << "OVERVIEW: LLVM profile data tools\n\n"
              << "USAGE: " << ProgName << " <command> [args...]\n"
              << "USAGE: " << ProgName << " <command> -help\n\n"
              << "See each individual command --help for more details.\n"
-             << "Available commands: merge, show, overlap\n";
+             << "Available commands: "
+             << join(map_range(llvm_profdata_subcommands,
+                               [](auto const &KV) { return std::get<0>(KV); }),
+                     ", ")
+             << "\n";
       return 0;
     }
 
     if (strcmp(argv[1], "--version") == 0) {
       outs() << ProgName << '\n';
       cl::PrintVersionMessage();
       return 0;
     }
   }
 
   if (argc < 2)
     errs() << ProgName << ": No command specified!\n";
   else
     errs() << ProgName << ": Unknown command!\n";
 
-  errs() << "USAGE: " << ProgName << " <merge|show|overlap|order> [args...]\n";
+  errs() << "USAGE: " << ProgName << " <"
+         << join(map_range(llvm_profdata_subcommands,
+                           [](auto const &KV) { return std::get<0>(KV); }),
+                 "|")
+         << "> [args...]\n";
   return 1;
 }