[LLD][MinGW] Add --fatal-warnings and --no-fatal-warnings flags

[mati865]

Summary

Couldn't find the pattern for ordering flags in Driver.cpp so put it in a random position.

[mstorsjo]

Couldn't find the pattern for ordering flags in Driver.cpp so put it in a random position.

Yeah there's probably no very clear pattern, so far it's mostly grouped according to options that have similar code for handling them.

lld/MinGW/Options.td

49

Typo, erros.

lld/test/MinGW/driver.test

298

This line doesn't seem to match the default indicated both in Options.td and the code (and the CI also seems to conclude that this fails).

[mati865]

Fix typo and the test

[mati865]

lld/test/MinGW/driver.test

298

I have no idea how that happened, I must have ran tests before saving the file.

[mstorsjo]

LGTM

lld/MinGW/Driver.cpp

if (auto *a = args.getLastArg(OPT_pdb)) {
     if (!v.empty())
       add("-pdb:" + v);
   } else if (args.hasArg(OPT_strip_debug)) {
     add("-debug:symtab");
   } else if (!args.hasArg(OPT_strip_all)) {
     add("-debug:dwarf");
   }
 
+  if (args.hasFlag(OPT_fatal_warnings, OPT_no_fatal_warnings, false))
+    add("-WX");
+  else
+    add("-WX:no");
+
   if (args.hasArg(OPT_shared))
     add("-dll");
   if (args.hasArg(OPT_verbose))
     add("-verbose");
   if (args.hasArg(OPT_exclude_all_symbols))
     add("-exclude-all-symbols");
   if (args.hasArg(OPT_export_all_symbols))
     add("-export-all-symbols");

lld/MinGW/Options.td

def enable_auto_import: F<"enable-auto-import">,
     HelpText<"Automatically import data symbols from other DLLs where needed">;
 def enable_runtime_pseudo_reloc: F<"enable-runtime-pseudo-reloc">,
     HelpText<"Allow automatic imports that require runtime fixups">;
 defm entry: Eq<"entry", "Name of entry point symbol">, MetaVarName<"<entry>">;
 def exclude_all_symbols: F<"exclude-all-symbols">,
     HelpText<"Don't automatically export any symbols">;
 def export_all_symbols: F<"export-all-symbols">,
     HelpText<"Export all symbols even if a def file or dllexport attributes are used">;
+defm fatal_warnings: B<"fatal-warnings",
+    "Treat warnings as errors",
+    "Do not treat warnings as errors (default)">;
 defm file_alignment: Eq<"file-alignment", "Set file alignment">;
 defm gc_sections: B<"gc-sections",
     "Remove unused sections",
     "Don't remove unused sections">;
 def help: F<"help">, HelpText<"Print option help">;
 def icf: J<"icf=">, HelpText<"Identical code folding">;
 def image_base: S<"image-base">, HelpText<"Base address of the program">;
 defm insert_timestamp: B<"insert-timestamp",

lld/test/MinGW/driver.test

 RUN: ld.lld -### -m i386pep foo.o | FileCheck -check-prefix DEMANGLE %s
 RUN: ld.lld -### -m i386pep foo.o -demangle | FileCheck -check-prefix DEMANGLE %s
 RUN: ld.lld -### -m i386pep foo.o --demangle | FileCheck -check-prefix DEMANGLE %s
 DEMANGLE: -demangle{{ }}
 
 RUN: ld.lld -### -m i386pep foo.o -no-demangle | FileCheck -check-prefix NO-DEMANGLE %s
 RUN: ld.lld -### -m i386pep foo.o --no-demangle | FileCheck -check-prefix NO-DEMANGLE %s
 NO-DEMANGLE: -demangle:no
+
+RUN: ld.lld -### -m i386pep foo.o -fatal-warnings | FileCheck -check-prefix FATAL_WARNINGS %s
+RUN: ld.lld -### -m i386pep foo.o --fatal-warnings | FileCheck -check-prefix FATAL_WARNINGS %s
+FATAL_WARNINGS: -WX{{ }}
+
+RUN: ld.lld -### -m i386pep foo.o | FileCheck -check-prefix NO-FATAL_WARNINGS %s
+RUN: ld.lld -### -m i386pep foo.o -no-fatal-warnings | FileCheck -check-prefix NO-FATAL_WARNINGS %s
+RUN: ld.lld -### -m i386pep foo.o --no-fatal-warnings | FileCheck -check-prefix NO-FATAL_WARNINGS %s
+NO-FATAL_WARNINGS: -WX:no