[clang] [clang] [Driver] Ensure we error on lto with link.exe and target `*-windows-msvc` on non cl driver modes (PR #109607)

[Max Winkler via cfe-commits]

https://github.com/MaxEW707 created https://github.com/llvm/llvm-project/pull/109607

Similar to previous PRs I've done to change some `IsCLMode` checks to `isWindowsMSVCEnvironment`.
I stumbled into this one accidentally last week. I did some greps and I think this is the last one for now. All the remaining `IsCLMode` checks are only valid for the cl driver mode.

For the `*-windows-msvc` target MSVC link.exe and lld are supported. LTO isn't supported with MSVC link.exe and so we error when lto is enabled but MSVC link.exe is being used. However we only error if the driver mode is cl.
If we are using the clang driver with the `*-windows-msvc` target then ensure an error is also emitted when LTO and MSVC link.exe are used together.


>From 703262d8d0f7575e2913b0cfc55e0eac53d43779 Mon Sep 17 00:00:00 2001
From: MaxEW707 <max.enrico.winkler at gmail.com>
Date: Sat, 21 Sep 2024 18:46:40 -0700
Subject: [PATCH] Ensure we error on lto with link.exe on non-cl mode driver

---
 clang/lib/Driver/Driver.cpp      | 3 ++-
 clang/test/Driver/cl-options.c   | 2 ++
 clang/test/Driver/clang_f_opts.c | 2 +-
 clang/test/Driver/lto.c          | 2 +-
 clang/test/Driver/thinlto.c      | 2 +-
 clang/test/Driver/thinlto.cu     | 2 +-
 6 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 44548fa9d706fb..a9506cf911b950 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -4011,7 +4011,8 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args,
     // Emitting LLVM while linking disabled except in HIPAMD Toolchain
     if (Args.hasArg(options::OPT_emit_llvm) && !Args.hasArg(options::OPT_hip_link))
       Diag(clang::diag::err_drv_emit_llvm_link);
-    if (IsCLMode() && LTOMode != LTOK_None &&
+    if (C.getDefaultToolChain().getTriple().isWindowsMSVCEnvironment() &&
+        LTOMode != LTOK_None &&
         !Args.getLastArgValue(options::OPT_fuse_ld_EQ)
              .equals_insensitive("lld"))
       Diag(clang::diag::err_drv_lto_without_lld);
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
index a6f338533ad763..f0de6289d95223 100644
--- a/clang/test/Driver/cl-options.c
+++ b/clang/test/Driver/cl-options.c
@@ -626,6 +626,8 @@
 // LTO-THIN: -flto=thin
 
 // RUN: not %clang_cl -### -Fe%t.exe -entry:main -flto -- %s 2>&1 | FileCheck -check-prefix=LTO-WITHOUT-LLD %s
+// RUN: not %clang_cl -### -fuse-ld=link -Fe%t.exe -entry:main -flto -- %s 2>&1 | FileCheck -check-prefix=LTO-WITHOUT-LLD %s
+// RUN: not %clang -### --target=x86_64-windows-msvc -fuse-ld=link -Fe%t.exe -entry:main -flto -- %s 2>&1 | FileCheck -check-prefix=LTO-WITHOUT-LLD %s
 // LTO-WITHOUT-LLD: LTO requires -fuse-ld=lld
 
 // RUN: %clang_cl  -### -- %s 2>&1 | FileCheck -check-prefix=NOCFGUARD %s
diff --git a/clang/test/Driver/clang_f_opts.c b/clang/test/Driver/clang_f_opts.c
index adb6f075b6c15d..5dfd86f7515236 100644
--- a/clang/test/Driver/clang_f_opts.c
+++ b/clang/test/Driver/clang_f_opts.c
@@ -605,7 +605,7 @@
 // RUN: %clang -### -S -fjmc -g -fno-jmc -target x86_64-pc-windows-msvc %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC %s
 // 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 -target x86_64-pc-windows-msvc %s 2>&1 | FileCheck -check-prefix=CHECK_NOJMC_LTO %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 -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/lto.c b/clang/test/Driver/lto.c
index b6c89eb99e2741..d3e22d9a1196b2 100644
--- a/clang/test/Driver/lto.c
+++ b/clang/test/Driver/lto.c
@@ -5,7 +5,7 @@
 // CHECK-COMPILE-ACTIONS: 2: compiler, {1}, ir
 // CHECK-COMPILE-ACTIONS: 3: backend, {2}, lto-bc
 
-// RUN: %clang -ccc-print-phases %s -flto 2> %t
+// RUN: %clang -ccc-print-phases -fuse-ld=lld %s -flto 2> %t
 // RUN: FileCheck -check-prefix=CHECK-COMPILELINK-ACTIONS < %t %s
 //
 // CHECK-COMPILELINK-ACTIONS: 0: input, "{{.*}}lto.c", c
diff --git a/clang/test/Driver/thinlto.c b/clang/test/Driver/thinlto.c
index e08435f71cc0b0..b54ef307628851 100644
--- a/clang/test/Driver/thinlto.c
+++ b/clang/test/Driver/thinlto.c
@@ -5,7 +5,7 @@
 // CHECK-COMPILE-ACTIONS: 2: compiler, {1}, ir
 // CHECK-COMPILE-ACTIONS: 3: backend, {2}, lto-bc
 
-// RUN: %clang -ccc-print-phases %s -flto=thin 2> %t
+// RUN: %clang -fuse-ld=lld -ccc-print-phases %s -flto=thin 2> %t
 // RUN: FileCheck -check-prefix=CHECK-COMPILELINK-ACTIONS < %t %s
 //
 // CHECK-COMPILELINK-ACTIONS: 0: input, "{{.*}}thinlto.c", c
diff --git a/clang/test/Driver/thinlto.cu b/clang/test/Driver/thinlto.cu
index c175aae37c718d..b7875884a24aa8 100644
--- a/clang/test/Driver/thinlto.cu
+++ b/clang/test/Driver/thinlto.cu
@@ -6,7 +6,7 @@
 // CHECK-COMPILE-ACTIONS-NOT: lto-bc
 // CHECK-COMPILE-ACTIONS: 12: backend, {11}, lto-bc, (host-cuda)
 
-// RUN: %clangxx -ccc-print-phases --no-offload-new-driver -nocudainc -nocudalib %s -flto=thin 2> %t
+// RUN: %clangxx -ccc-print-phases -fuse-ld=lld --no-offload-new-driver -nocudainc -nocudalib %s -flto=thin 2> %t
 // RUN: FileCheck -check-prefix=CHECK-COMPILELINK-ACTIONS < %t %s
 //
 // CHECK-COMPILELINK-ACTIONS: 0: input, "{{.*}}thinlto.cu", cuda, (host-cuda)