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

Author: MaxEW707

clang/lib/Driver/Driver.cpp

@@ -4022,7 +4022,8 @@ 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);

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

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

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 %if target={{.*-windows-msvc.*}} %{ -fuse-ld=lld %} -flto %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-COMPILELINK-ACTIONS < %t %s
 //
 // CHECK-COMPILELINK-ACTIONS: 0: input, "{{.*}}lto.c", c

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 -ccc-print-phases %if target={{.*-windows-msvc.*}} %{ -fuse-ld=lld %} -flto=thin %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-COMPILELINK-ACTIONS < %t %s
 //
 // CHECK-COMPILELINK-ACTIONS: 0: input, "{{.*}}thinlto.c", c

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 %if target={{.*-windows-msvc.*}} %{ -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)