[LLD] [COFF] Allow invoking lib.exe mode via -lib in addition to /lib

Remove a stray -lib argument in guardcf-lto.ll; llvm-lib doesn't
support generating import libs from a def file unlike lib.exe.
Previously this worked because the -lib argument was ignored
(printing only a warning).

Differential Revision: https://reviews.llvm.org/D96699

GitOrigin-RevId: 075539ddf6525f5dac31d9b5506cd58c44108633
diff --git a/COFF/Driver.cpp b/COFF/Driver.cpp
index 07fa7cc..69ed292 100644
--- a/COFF/Driver.cpp
+++ b/COFF/Driver.cpp
@@ -1244,7 +1244,8 @@
 
   // If the first command line argument is "/lib", link.exe acts like lib.exe.
   // We call our own implementation of lib.exe that understands bitcode files.
-  if (argsArr.size() > 1 && StringRef(argsArr[1]).equals_lower("/lib")) {
+  if (argsArr.size() > 1 && (StringRef(argsArr[1]).equals_lower("/lib") ||
+                             StringRef(argsArr[1]).equals_lower("-lib"))) {
     if (llvm::libDriverMain(argsArr.slice(1)) != 0)
       fatal("lib failed");
     return;
diff --git a/test/COFF/driver.test b/test/COFF/driver.test
index 363df6d..8f58ff4 100644
--- a/test/COFF/driver.test
+++ b/test/COFF/driver.test
@@ -11,6 +11,7 @@
 BADFILE: bad file type. Did you specify a DLL instead of an import library?
 
 # RUN: lld-link /lib /help | FileCheck -check-prefix=LIBHELP %s
+# RUN: lld-link -lib -help | FileCheck -check-prefix=LIBHELP %s
 LIBHELP: OVERVIEW: LLVM Lib
 
 # RUN: env LLD_IN_TEST=1 not lld-link /WX /lib 2>&1 | FileCheck -check-prefix=LIBBAD %s
diff --git a/test/COFF/guardcf-lto.ll b/test/COFF/guardcf-lto.ll
index e365537..7811f44 100644
--- a/test/COFF/guardcf-lto.ll
+++ b/test/COFF/guardcf-lto.ll
@@ -1,7 +1,7 @@
 ; REQUIRES: x86
 ; Set up an import library for a DLL that will do the indirect call.
 ; RUN: echo -e 'LIBRARY library\nEXPORTS\n  do_indirect_call\n' > %t.def
-; RUN: lld-link -lib -def:%t.def -out:%t.lib -machine:x64
+; RUN: lld-link -def:%t.def -out:%t.lib -machine:x64
 
 ; Generate an object that will have the load configuration normally provided by
 ; the CRT.