[lld-macho] Implement -noall_load

[keith]

Summary

This flag is the default, so in ld64 it is not implemented, but it can
be useful to negate previous -all_load arguments. Specifically if your
build system has some global linker flags, that you may want to negate
for specific links. We use something like this today to make sure some
C++ symbols are automatically discovered for all links, which passing
-all_load hides.

[oontvoo]

LG thanks!

lld/test/MachO/archive.s

35

for completeness, can we have a test where -noall_load is used alone?

[keith]

Add test case for only using -noall_load

lld/MachO/Driver.cpp

config->ltoNewPassManager =
       args.hasFlag(OPT_no_lto_legacy_pass_manager, OPT_lto_legacy_pass_manager,
                    LLVM_ENABLE_NEW_PASS_MANAGER);
   config->ltoo = args::getInteger(args, OPT_lto_O, 2);
   if (config->ltoo > 3)
     error("--lto-O: invalid optimization level: " + Twine(config->ltoo));
   config->thinLTOCacheDir = args.getLastArgValue(OPT_cache_path_lto);
   config->thinLTOCachePolicy = getLTOCachePolicy(args);
   config->runtimePaths = args::getStrings(args, OPT_rpath);
-  config->allLoad = args.hasArg(OPT_all_load);
+  config->allLoad = args.hasFlag(OPT_all_load, OPT_noall_load, false);
   config->archMultiple = args.hasArg(OPT_arch_multiple);
   config->applicationExtension = args.hasFlag(
       OPT_application_extension, OPT_no_application_extension, false);
   config->exportDynamic = args.hasArg(OPT_export_dynamic);
   config->forceLoadObjC = args.hasArg(OPT_ObjC);
   config->forceLoadSwift = args.hasArg(OPT_force_load_swift_libs);
   config->deadStripDylibs = args.hasArg(OPT_dead_strip_dylibs);
   config->demangle = args.hasArg(OPT_demangle);

lld/MachO/Options.td

def upward_framework : Separate<["-"], "upward_framework">,
     Group<grp_libs>;
 def F : JoinedOrSeparate<["-"], "F">,
     MetaVarName<"<dir>">,
     HelpText<"Add dir to the framework search path">,
     Group<grp_libs>;
 def all_load : Flag<["-"], "all_load">,
     HelpText<"Load all members of all static archive libraries">,
     Group<grp_libs>;
+def noall_load : Flag<["-"], "noall_load">,
+    HelpText<"Don't load all static members from archives, this is the default, this negates -all_load">,
+    Group<grp_libs>;
 def ObjC : Flag<["-"], "ObjC">,
     HelpText<"Load all members of static archives that are an Objective-C class or category.">,
     Group<grp_libs>;
 def force_load : Separate<["-"], "force_load">,
     MetaVarName<"<path>">,
     HelpText<"Load all members static archive library at <path>">,
     Group<grp_libs>;
 def force_load_swift_libs : Flag<["-"], "force_load_swift_libs">,

 def single_module : Flag<["-"], "single_module">,
     HelpText<"Unnecessary option: this is already the default">,
     Flags<[HelpHidden]>,
     Group<grp_deprecated>;
 def no_dead_strip_inits_and_terms : Flag<["-"], "no_dead_strip_inits_and_terms">,
     HelpText<"Unnecessary option: initialization and termination are roots of the dead strip graph, so never dead stripped">,
     Flags<[HelpHidden]>,
     Group<grp_deprecated>;
-def noall_load : Flag<["-"], "noall_load">,
-    HelpText<"Unnecessary option: this is already the default">,
-    Flags<[HelpHidden]>,
-    Group<grp_deprecated>;
 
 def grp_obsolete : OptionGroup<"obsolete">, HelpText<"OBSOLETE">;
 
 def sectorder : MultiArg<["-"], "sectorder", 3>,
     MetaVarName<"<segname> <sectname> <orderfile>">,
     HelpText<"Obsolete. Replaced by more general -order_file option">,
     Group<grp_obsolete>;
 def lto_library : Separate<["-"], "lto_library">,

lld/test/MachO/archive.s

 # ARCHIVE-FIRST: T _bar
 # ARCHIVE-FIRST: T _boo
 # ARCHIVE-FIRST: T _main
 
 # RUN: llvm-nm %t/test.out | FileCheck %s --check-prefix VISIBLE
 # VISIBLE-NOT: T _undefined
 # VISIBLE-NOT: T _unused
 
-# RUN: %lld %t/test.a %t/main.o -o %t/all-load -all_load
+# RUN: %lld %t/test.a %t/main.o -o %t/all-load -noall_load -all_load
 # RUN: llvm-nm %t/all-load | FileCheck %s --check-prefix ALL-LOAD
 # ALL-LOAD: T _bar
 # ALL-LOAD: T _boo
 # ALL-LOAD: T _main
 # ALL-LOAD: T _unused
 
+# RUN: %lld %t/test.a %t/main.o -o %t/no-all-load -all_load -noall_load
+# RUN: llvm-nm %t/no-all-load | FileCheck %s --check-prefix NO-ALL-LOAD
+# NO-ALL-LOAD-NOT: T _unused
+
 ## Multiple archives defining the same symbols aren't an issue, due to lazy
 ## loading
 # RUN: cp %t/test.a %t/test2.a
 # RUN: %lld %t/test.a %t/test2.a %t/main.o -o /dev/null
 
 #--- 2.s
 .globl _boo
 _boo: