[lld-macho] Specify the complete set of command-line options for ld64

This is a complete Options.td compiled from ld(1) dated 2018-03-07 and
cross checked with ld64 source code version 512.4 dated 2018-03-18.

This is the first in a series of diffs for argument handling. Follow-ups
will include switch cases for all the new instances of `OPT_foo`, and
parsing/validation of arguments attached to options, e.g., more code
akin to `OPT_platform_version` and associated `parsePlatformVersion()`.

Reviewed By: smeenai

Differential Revision: https://reviews.llvm.org/D80582

lld/MachO/Driver.cpp

@@ -37,6 +37,7 @@
 using namespace llvm;
 using namespace llvm::MachO;
 using namespace llvm::sys;
+using namespace llvm::opt;
 using namespace lld;
 using namespace lld::macho;
 
@@ -74,6 +75,12 @@ opt::InputArgList MachOOptTable::parse(ArrayRef<const char *> argv) {
   return args;
 }
 
+void MachOOptTable::printHelp(const char *argv0, bool showHidden) const {
+  PrintHelp(lld::outs(), (std::string(argv0) + " [options] file...").c_str(),
+            "LLVM Linker", showHidden);
+  lld::outs() << "\n";
+}
+
 static Optional<std::string> findLibrary(StringRef name) {
   std::string stub = (llvm::Twine("lib") + name + ".tbd").str();
   std::string shared = (llvm::Twine("lib") + name + ".dylib").str();
@@ -259,15 +266,41 @@ static bool markSubLibrary(StringRef searchName) {
   return false;
 }
 
-static void handlePlatformVersion(opt::ArgList::iterator &it,
-                                  const opt::ArgList::iterator &end) {
-  // -platform_version takes 3 args, which LLVM's option library doesn't
-  // support directly.  So this explicitly handles that.
-  // FIXME: stash skipped args for later use.
-  for (int i = 0; i < 3; ++i) {
-    ++it;
-    if (it == end || (*it)->getOption().getID() != OPT_INPUT)
-      fatal("usage: -platform_version platform min_version sdk_version");
+static void handlePlatformVersion(const opt::Arg *arg) {
+  // TODO: implementation coming very soon ...
+}
+
+static void warnIfDeprecatedOption(const opt::Option &opt) {
+  if (!opt.getGroup().isValid())
+    return;
+  if (opt.getGroup().getID() == OPT_grp_deprecated) {
+    warn("Option `" + opt.getPrefixedName() + "' is deprecated in ld64:");
+    warn(opt.getHelpText());
+  }
+}
+
+static void warnIfUnimplementedOption(const opt::Option &opt) {
+  if (!opt.getGroup().isValid())
+    return;
+  switch (opt.getGroup().getID()) {
+  case OPT_grp_deprecated:
+    // warn about deprecated options elsewhere
+    break;
+  case OPT_grp_undocumented:
+    warn("Option `" + opt.getPrefixedName() +
+         "' is undocumented. Should lld implement it?");
+    break;
+  case OPT_grp_obsolete:
+    warn("Option `" + opt.getPrefixedName() +
+         "' is obsolete. Please modernize your usage.");
+    break;
+  case OPT_grp_ignored:
+    warn("Option `" + opt.getPrefixedName() + "' is ignored.");
+    break;
+  default:
+    warn("Option `" + opt.getPrefixedName() +
+         "' is not yet implemented. Stay tuned...");
+    break;
   }
 }
 
@@ -282,6 +315,14 @@ bool macho::link(llvm::ArrayRef<const char *> argsArr, bool canExitEarly,
   MachOOptTable parser;
   opt::InputArgList args = parser.parse(argsArr.slice(1));
 
+  if (args.hasArg(OPT_help_hidden)) {
+    parser.printHelp(argsArr[0], /*showHidden=*/true);
+    return true;
+  } else if (args.hasArg(OPT_help)) {
+    parser.printHelp(argsArr[0], /*showHidden=*/false);
+    return true;
+  }
+
   config = make<Configuration>();
   symtab = make<SymbolTable>();
   target = createTargetInfo(args);
@@ -302,9 +343,9 @@ bool macho::link(llvm::ArrayRef<const char *> argsArr, bool canExitEarly,
     return !errorCount();
   }
 
-  for (opt::ArgList::iterator it = args.begin(), end = args.end(); it != end;
-       ++it) {
-    const opt::Arg *arg = *it;
+  for (const auto &arg : args) {
+    const auto &opt = arg->getOption();
+    warnIfDeprecatedOption(opt);
     switch (arg->getOption().getID()) {
     case OPT_INPUT:
       addFile(arg->getValue());
@@ -318,10 +359,20 @@ bool macho::link(llvm::ArrayRef<const char *> argsArr, bool canExitEarly,
       error("library not found for -l" + name);
       break;
     }
-    case OPT_platform_version: {
-      handlePlatformVersion(it, end); // Can advance "it".
+    case OPT_platform_version:
+      handlePlatformVersion(arg);
+      break;
+    case OPT_o:
+    case OPT_dylib:
+    case OPT_e:
+    case OPT_L:
+    case OPT_Z:
+    case OPT_arch:
+      // handled elsewhere
+      break;
+    default:
+      warnIfUnimplementedOption(opt);
       break;
-    }
     }
   }
 

lld/MachO/Driver.h

@@ -19,6 +19,7 @@ class MachOOptTable : public llvm::opt::OptTable {
 public:
   MachOOptTable();
   llvm::opt::InputArgList parse(ArrayRef<const char *> argv);
+  void printHelp(const char *argv0, bool showHidden) const;
 };
 
 // Create enum with OPT_xxx values for each option in Options.td

lld/test/MachO/platform-version.test

@@ -1,16 +1,17 @@
 # RUN: not lld -flavor darwinnew -arch x86_64 -platform_version 2>&1 \
-# RUN:     | FileCheck --check-prefix=FAIL %s
+# RUN:     | FileCheck --check-prefix=MISSING %s
 # RUN: not lld -flavor darwinnew -arch x86_64 -platform_version macos 2>&1 \
-# RUN:     | FileCheck --check-prefix=FAIL %s
+# RUN:     | FileCheck --check-prefix=MISSING %s
 # RUN: not lld -flavor darwinnew -arch x86_64 -platform_version macos 10.15 2>&1 \
-# RUN:     | FileCheck --check-prefix=FAIL %s
+# RUN:     | FileCheck --check-prefix=MISSING %s
 # RUN: not lld -flavor darwinnew -arch x86_64 -platform_version macos -lfoo 10.15 2>&1 \
-# RUN:     | FileCheck --check-prefix=FAIL %s
+# RUN:     | FileCheck --check-prefix=GOOD %s
 # RUN: not lld -flavor darwinnew -arch x86_64 -platform_version macos 10.15 10.15.4 2>&1 \
 # RUN:     | FileCheck --check-prefix=GOOD %s
 # RUN: not lld -flavor darwinnew -arch x86_64 -platform_version macos 10.15 10.15.4 foobar 2>&1 \
 # RUN:     | FileCheck --check-prefix=FAIL_FILE %s
 
+MISSING: -platform_version: missing argument
 FAIL: usage: -platform_version platform min_version sdk_version
 GOOD: undefined symbol: _main
 FAIL_FILE: cannot open foobar

llvm/include/llvm/Option/Option.h

@@ -135,6 +135,18 @@ public:
     return Ret;
   }
 
+  /// Get the help text for this option.
+  StringRef getHelpText() const {
+    assert(Info && "Must have a valid info!");
+    return Info->HelpText;
+  }
+
+  /// Get the meta-variable list for this option.
+  StringRef getMetaVar() const {
+    assert(Info && "Must have a valid info!");
+    return Info->MetaVar;
+  }
+
   unsigned getNumArgs() const { return Info->Param; }
 
   bool hasNoOptAsInput() const { return Info->Flags & RenderAsInput;}