[lld-macho] Ignore -platform_version and -syslibroot flags.

[thakis]

Summary

clang passes these flags; this makes it easier to try clang -v
output with ld -flavor darwinnew.

[int3]

Thanks for putting this up!

lld/test/MachO/platform-version.test

11–12

not sure this test really fits into this file, but not a big deal I guess

15

I've written other flag tests (specifically silent-ignore.test) using -v instead so that the lack of an input file doesn't result in an error.

Speaking of which, could you add -syslibroot to the silent-ignore.test? Thanks!

[thakis]

Thanks! Submitting.

lld/test/MachO/platform-version.test

11–12

The idea is to test that the 4th parameter after -platform_version isn't ignored. Passing a non-existent input was the best thing I could think of. I guess I could try a -l flag instead and then pass an existing input that needs the -l to successfully link, but it's a bit more boilerplate. Let me know if you prefer that and I'll change it in a follow-up.

15

For the other ignored flags that works because they don't need any code. But -v makes lld exit before the option parsing loop modified in this change runs, so it doesn't work for -platform_version.

I added a test for -syslibroot, thanks.

[int3]

lld/test/MachO/platform-version.test

11–12

Ah got it. It's fine this way, thanks!

lld/MachO/Driver.cpp

if (auto *dylibFile = dyn_cast<DylibFile>(file)) {
         dylibFile->reexport = true;
         return true;
       }
     }
   }
   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");
+  }
+}
+
 bool macho::link(llvm::ArrayRef<const char *> argsArr, bool canExitEarly,
                  raw_ostream &stdoutOS, raw_ostream &stderrOS) {
   lld::stdoutOS = &stdoutOS;
   lld::stderrOS = &stderrOS;
 
   stderrOS.enable_colors(stderrOS.has_colors());
   // TODO: Set up error handler properly, e.g. the errorLimitExceededMsg
 
if (args.hasArg(OPT_v)) {
     message(getLLDVersion());
     std::vector<StringRef> &searchPaths = config->searchPaths;
     message("Library search paths:\n" +
             llvm::join(searchPaths.begin(), searchPaths.end(), "\n"));
     freeArena();
     return !errorCount();
   }
 
-  for (opt::Arg *arg : args) {
+  for (opt::ArgList::iterator it = args.begin(), end = args.end(); it != end;
+       ++it) {
+    const opt::Arg *arg = *it;
     switch (arg->getOption().getID()) {
     case OPT_INPUT:
       addFile(arg->getValue());
       break;
     case OPT_l:
       if (Optional<std::string> path = findDylib(arg->getValue()))
         addFile(*path);
       break;
+    case OPT_platform_version: {
+      handlePlatformVersion(it, end);  // Note: Can advance "it".
+      break;
+    }
     }
   }
 
   // Now that all dylibs have been loaded, search for those that should be
   // re-exported.
   for (opt::Arg *arg : args.filtered(OPT_sub_library)) {
     config->hasReexports = true;
     StringRef searchName = arg->getValue();

lld/MachO/Options.td

def sub_library: Separate<["-"], "sub_library">, MetaVarName<"<libname>">,
   HelpText<"Re-export the specified dylib">;
 
 def v: Flag<["-"], "v">, HelpText<"Display the version number and exit">;
 
 // Ignored options
 def: Flag<["-"], "demangle">;
 def: Flag<["-"], "dynamic">;
 def: Flag<["-"], "no_deduplicate">;
+def platform_version: Flag<["-"], "platform_version">;
 def: Separate<["-"], "lto_library">;
 def: Separate<["-"], "macosx_version_min">;
+def: Separate<["-"], "syslibroot">;

lld/test/MachO/platform-version.test

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