[LLD] [MinGW] Add an option -Xlink for passing options through to lld-link

[mstorsjo]

Summary

Also move the -mllvm option to the right section of the options list.

[ruiu]

MinGW/Options.td

34

I would prefer we always require = after -Xlink, because -Xlink=-lldmap is easier to read and less confusing than -Xlink -lldmap on command line.

[mstorsjo]

MinGW/Options.td

34

Is there any predecent for such style elsewhere? The -Xfoo -bar style is used by clang (or does that one also support -Xfoo=-bar?), and there's also the -Wl,-bar style used in the clang and gcc drivers for some things. That syntax would be a little messy here though, since you'd already need to use -Wl, to pass options from clang to the mingw linker frontend.

[ruiu]

MinGW/Options.td

34

I don't know of any precedent of the style in compilers, but there might be in some command that takes meta-options. At least it helps me understand a command line if = is mandatory. If you feel strongly, I'm fine without = though.

[mstorsjo]

MinGW/Options.td

34

I don't feel very strongly about it, so let's go with -Xlink=-foo.

[mstorsjo]

Using the form -Xlink=-foo as requested.

[ruiu]

LGTM

MinGW/Options.td

34

GNU ld manual says that it takes either -foo or --foo except a single letter option or an option starting with 'o' (to avoid conflict with -o). So, you want to use J instead of Joined to accept both -Xlink and --Xlink.

MinGW/Driver.cpp

else if (S == "arm64pe")
       Add("-machine:arm64");
     else
       error("unknown parameter: -m" + S);
   }
 
   for (auto *A : Args.filtered(OPT_mllvm))
     Add("-mllvm:" + StringRef(A->getValue()));
 
+  for (auto *A : Args.filtered(OPT_Xlink))
+    Add(A->getValue());
+
   if (Args.getLastArgValue(OPT_m) == "i386pe")
     Add("-alternatename:__image_base__=___ImageBase");
   else
     Add("-alternatename:__image_base__=__ImageBase");
 
   std::vector<StringRef> SearchPaths;
   for (auto *A : Args.filtered(OPT_L))
     SearchPaths.push_back(A->getValue());

MinGW/Options.td

 include "llvm/Option/OptParser.td"
 
 class F<string name>: Flag<["--", "-"], name>;
 class J<string name>: Joined<["--", "-"], name>;
 class S<string name>: Separate<["--", "-"], name>;
 
 def L: JoinedOrSeparate<["-"], "L">, MetaVarName<"<dir>">,
   HelpText<"Add a directory to the library search path">;
 def entry: S<"entry">, MetaVarName<"<entry>">,
   HelpText<"Name of entry point symbol">;
 def export_all_symbols: F<"export-all-symbols">,
     HelpText<"Export all symbols even if a def file or dllexport attributes are used">;
 def l: JoinedOrSeparate<["-"], "l">, MetaVarName<"<libName>">,
   HelpText<"Root name of library to use">;
 def m: JoinedOrSeparate<["-"], "m">, HelpText<"Set target emulation">;
-def mllvm: S<"mllvm">;
 def no_whole_archive: F<"no-whole-archive">,
     HelpText<"No longer include all object files for following archives">;
 def o: JoinedOrSeparate<["-"], "o">, MetaVarName<"<path>">,
   HelpText<"Path to file to write output">;
 def out_implib: Separate<["--"], "out-implib">, HelpText<"Import library name">;
 def out_implib_eq: Joined<["--"], "out-implib=">, Alias<out_implib>;
 def output_def: S<"output-def">, HelpText<"Output def file">;
 def shared: F<"shared">, HelpText<"Build a shared object">;
 def subs: S<"subsystem">, HelpText<"Specify subsystem">;
 def stack: S<"stack">;
 def whole_archive: F<"whole-archive">,
     HelpText<"Include all object files for following archives">;
 def verbose: F<"verbose">, HelpText<"Verbose mode">;
 
 // LLD specific options
 def _HASH_HASH_HASH : Flag<["-"], "###">,
     HelpText<"Print (but do not run) the commands to run for this compilation">;
+def mllvm: S<"mllvm">;
+def Xlink : Joined<["-"], "Xlink=">, MetaVarName<"<arg>">,
+    HelpText<"Pass <arg> to the COFF linker">;
 
 // Currently stubs to avoid errors
 def Bdynamic: F<"Bdynamic">, HelpText<"Link against shared libraries">;
 def Bstatic: F<"Bstatic">, HelpText<"Do not link against shared libraries">;
 def O: Joined<["-"], "O">, HelpText<"Optimize output file size">;
 def enable_auto_image_base: F<"enable-auto-image-base">;
 def enable_auto_import: F<"enable-auto-import">;
 def full_shutdown: Flag<["--"], "full-shutdown">;
 def major_image_version: S<"major-image-version">;
 def minor_image_version: S<"minor-image-version">;
 def sysroot: J<"sysroot">, HelpText<"Sysroot">;
 def v: Flag<["-"], "v">, HelpText<"Display the version number">;
 def version: F<"version">, HelpText<"Display the version number and exit">;
 
 // Alias
 def alias_entry_e: JoinedOrSeparate<["-"], "e">, Alias<entry>;

test/MinGW/driver.test

 RUN: ld.lld -### -m i386pep foo.o | FileCheck -check-prefix MINGW-FLAG %s
 MINGW-FLAG: -lldmingw
 
 RUN: ld.lld -### -m i386pep foo.o --export-all-symbols | FileCheck -check-prefix EXPORT-ALL %s
 EXPORT-ALL: -export-all-symbols
 
 RUN: ld.lld -### -m i386pep foo.o --output-def out.def | FileCheck -check-prefix OUTPUT-DEF %s
 OUTPUT-DEF: -output-def:out.def
+
+RUN: ld.lld -### -m i386pep foo.o -Xlink=-lldmap | FileCheck -check-prefix XLINK %s
+XLINK: -lldmap