[clang] [clang][Driver] Allow -fuse-lld=lld-link when lto is enabled on *windows-msvc targets (PR #113966)

[Zhaoshi Zheng via cfe-commits]

https://github.com/zhaoshiz created https://github.com/llvm/llvm-project/pull/113966

Follow-up on https://github.com/llvm/llvm-project/pull/109607, we have a use case on WoA where `cmake -G "Unix Makefiles"` generates -fuse-ld=lld-link, which is disallowed by PR#109607.

>From 5259a3b00fe1b841e8548443036a943b169970dc Mon Sep 17 00:00:00 2001
From: Zhaoshi Zheng <zhaoshiz at quicinc.com>
Date: Mon, 28 Oct 2024 14:35:35 -0700
Subject: [PATCH] [clang][Driver] Allow -fuse-lld=lld-link when lto is enabled
 on *windows-msvc targets

Follow-up on https://github.com/llvm/llvm-project/pull/109607, we have a use
case on WoA where `cmake -G "Unix Makefiles"` generates -fuse-ld=lld-link,
which is disallowed by PR#109607.
---
 clang/lib/Driver/Driver.cpp      |  2 +-
 clang/test/Driver/clang_f_opts.c |  1 +
 clang/test/Driver/woa-lto.c      | 15 +++++++++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/Driver/woa-lto.c

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 9878a9dad78d40..c1c581e6c6df7c 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -4035,7 +4035,7 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args,
     if (C.getDefaultToolChain().getTriple().isWindowsMSVCEnvironment() &&
         LTOMode != LTOK_None &&
         !Args.getLastArgValue(options::OPT_fuse_ld_EQ)
-             .equals_insensitive("lld"))
+             .starts_with_insensitive("lld"))
       Diag(clang::diag::err_drv_lto_without_lld);
 
     // If -dumpdir is not specified, give a default prefix derived from the link
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index fd15552715cb35..2cfbe256bc7456 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -606,6 +606,7 @@
 // RUN: %clang -### -S -fjmc -g --target=x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_JMC %s
 // RUN: %clang -### -S -fjmc -g -fno-jmc --target=x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC %s
 // RUN: %clang -### -fjmc -g -flto -fuse-ld=lld --target=x86_64-pc-windows-msvc %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC_LTO %s
+// RUN: %clang -### -fjmc -g -flto -fuse-ld=lld-link --target=x86_64-pc-windows-msvc %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC_LTO %s
 // RUN: %clang -### -fjmc -g -flto --target=x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_JMC_LTO %s
 // RUN: %clang -### -fjmc -g -flto -fno-jmc --target=x86_64-unknown-linux %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC_LTO %s
 // CHECK_JMC_WARN: -fjmc requires debug info. Use -g or debug options that enable debugger's stepping function; option ignored
diff --git a/clang/test/Driver/woa-lto.c b/clang/test/Driver/woa-lto.c
new file mode 100644
index 00000000000000..25c42374c4d449
--- /dev/null
+++ b/clang/test/Driver/woa-lto.c
@@ -0,0 +1,15 @@
+// REQUIRES: aarch64-registered-target
+//
+// RUN: echo "int main() {} " > %t.c
+//
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto -fuse-ld=lld -c %t.c -o %t.o
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto -fuse-ld=lld -### %t.o 2>&1 | FileCheck %s
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto=thin -fuse-ld=lld -c %t.c -o %t.o
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto=thin -fuse-ld=lld -### %t.o 2>&1 | FileCheck %s
+//
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto -fuse-ld=lld-link -c %t.c -o %t.o
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto -fuse-ld=lld-link -### %t.o 2>&1 | FileCheck %s
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto=thin -fuse-ld=lld-link -c %t.c -o %t.o
+// RUN: %clang --target=aarch64-pc-windows-msvc -O3 -flto=thin -fuse-ld=lld-link -### %t.o 2>&1 | FileCheck %s
+//
+// CHECK: "{{.*}}lld-link" "-out:a.exe" "-defaultlib:libcmt" "-defaultlib:oldnames"