[LLD][COFF] Add /inferasanlibs to lld-link as ignored flag

[alvinhochun]

Summary

MSVC link.exe added this flag and MS STL started using this flag in
.drectve [1] when compiling with Clang with asan enabled, as reported
on https://github.com/llvm/llvm-project/issues/56300. This causes issues
with lld-link because it rejects any unknown flags in .drective sections.

As dc07867dc9991c982bd3441da19d6fcc16ea54d6 noted that, when using Clang
as the driver it explicitly passes the proper asan libraries. Therefore
it should be acceptable to ignore this flag in lld-link to at least
unbreak building with clang-cl and linking with lld-link.

[1]: https://github.com/microsoft/STL/blob/faaf094ee16bcbfb2c8d612fdb9334bcdef2fd0a/stl/inc/__msvc_sanitizer_annotate_container.hpp#L35

[alvinhochun]

Rebase

[alvinhochun]

I should note that although I did verify the new tests on Linux, I have not tested actually building things with this patch on Windows with the MSVC toolchain. It would be great if someone can test this end to end.

[mstorsjo]

LGTM, this looks reasonable to me.

[hans]

lgtm

+aeubanks fyi

lld/COFF/Driver.cpp

case OPT_subsystem: {
       }
       break;
     }
     // Only add flags here that link.exe accepts in
     // `#pragma comment(linker, "/flag")`-generated sections.
     case OPT_editandcontinue:
     case OPT_guardsym:
     case OPT_throwingnew:
+    case OPT_inferasanlibs:
+    case OPT_inferasanlibs_no:
       break;
     default:
       error(arg->getSpelling() + " is not allowed in .drectve (" +
             toString(file) + ")");
     }
   }
 }
 
void LinkerDriver::linkerMain(ArrayRef<const char *> argsArr) {
   config->pseudoRelocs = args.hasFlag(
       OPT_runtime_pseudo_reloc, OPT_runtime_pseudo_reloc_no, config->mingw);
   config->callGraphProfileSort = args.hasFlag(
       OPT_call_graph_profile_sort, OPT_call_graph_profile_sort_no, true);
   config->stdcallFixup =
       args.hasFlag(OPT_stdcall_fixup, OPT_stdcall_fixup_no, config->mingw);
   config->warnStdcallFixup = !args.hasArg(OPT_stdcall_fixup);
 
+  if (args.hasFlag(OPT_inferasanlibs, OPT_inferasanlibs_no, false))
+    warn("ignoring '/inferasanlibs', this flag is not supported");
+
   // Don't warn about long section names, such as .debug_info, for mingw or
   // when -debug:dwarf is requested.
   if (config->mingw || config->debugDwarf)
     config->warnLongSectionNames = false;
 
   if (config->incremental && args.hasArg(OPT_profile)) {
     warn("ignoring '/incremental' due to '/profile' specification");
     config->incremental = false;

lld/COFF/Options.td

 defm fixed : B<"fixed", "Disable base relocations",
                "Enable base relocations (default)">;
 defm highentropyva : B<"highentropyva",
                        "Enable 64-bit ASLR (default on 64-bit)",
                        "Disable 64-bit ASLR">;
 defm incremental : B<"incremental",
                      "Keep original import library if contents are unchanged",
                      "Overwrite import library even if contents are unchanged">;
+defm inferasanlibs : B<"inferasanlibs",
+                       "Unused, generates a warning",
+                       "No effect (default)">;
 defm integritycheck : B<"integritycheck",
                         "Set FORCE_INTEGRITY bit in PE header",
                         "No effect (default)">;
 defm largeaddressaware : B<"largeaddressaware",
                            "Enable large addresses (default on 64-bit)",
                            "Disable large addresses (default on 32-bit)">;
 defm nxcompat : B<"nxcompat", "Enable data execution prevention (default)",
                   "Disable data execution provention">;

lld/test/COFF/inferasanlibs-drectve.s

+# REQUIRES: x86
+
+# RUN: llvm-mc -triple=x86_64-windows %s -filetype=obj -o %t.obj
+
+# RUN: lld-link -dll -out:%t.dll -entry:entry %t.obj -subsystem:console 2>&1 | FileCheck --allow-empty --ignore-case %s
+
+# CHECK-NOT: ignoring unknown argument
+# CHECK-NOT: inferasanlibs
+# CHECK-NOT: is not allowed in .drectve
+
+  .global entry
+  .text
+entry:
+  ret
+  .section .drectve
+  .ascii " /INFERASANLIBS "

lld/test/COFF/inferasanlibs.test

+# RUN: yaml2obj %p/Inputs/ret42.yaml -o %t.obj
+
+# RUN: lld-link /out:%t.exe /entry:main %t.obj /inferasanlibs 2>&1 | FileCheck --check-prefix=POS %s
+# RUN: lld-link /out:%t.exe /entry:main %t.obj /inferasanlibs:no 2>&1 | FileCheck --allow-empty --check-prefix=NEG %s
+
+POS: ignoring '/inferasanlibs', this flag is not supported
+
+NEG-NOT: ignoring '/inferasanlibs', this flag is not supported