[clang] [clang][driver] Support `-x` for all languages in CL mode (PR #89772)

[via cfe-commits]

https://github.com/huangqinjin created https://github.com/llvm/llvm-project/pull/89772

After https://github.com/llvm/llvm-project/pull/68921, clang-cl gained option `-x` but only for CUDA/HIP. This commit simply removes the restriction on parameters to `-x`. Especially, it is able to use `-x c++-module` and `-x c++-user-header` to build C++20 modules and header units with clang-cl.

This effectively reverts commit fe082124faa8455cc9a68be5fdf10fc46a4d066c.

Closes https://github.com/llvm/llvm-project/issues/88006.

>From 9d89def66805c299654f38187e44be320656973d Mon Sep 17 00:00:00 2001
From: huangqinjin <huangqinjin at gmail.com>
Date: Tue, 23 Apr 2024 22:18:27 +0800
Subject: [PATCH] [clang][driver] Support `-x` for all languages in CL mode

After https://github.com/llvm/llvm-project/pull/68921,
clang-cl gained option `-x` but only for CUDA/HIP.
This commit simply removes the restriction on parameters to `-x`.
Especially, it is able to use `-x c++-module` and `-x c++-user-header`
to build C++20 modules and header units with clang-cl.

This effectively reverts commit fe082124faa8455cc9a68be5fdf10fc46a4d066c.

Closes https://github.com/llvm/llvm-project/issues/88006.
---
 clang/lib/Driver/Driver.cpp | 11 +----------
 clang/test/Driver/x-args.c  |  4 ----
 2 files changed, 1 insertion(+), 14 deletions(-)

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index e7335a61b10c53..0f425adfd32a6d 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -2636,22 +2636,13 @@ void Driver::BuildInputs(const ToolChain &TC, DerivedArgList &Args,
       Diag(clang::diag::note_drv_t_option_is_global);
   }
 
-  // CUDA/HIP and their preprocessor expansions can be accepted by CL mode.
   // Warn -x after last input file has no effect
-  auto LastXArg = Args.getLastArgValue(options::OPT_x);
-  const llvm::StringSet<> ValidXArgs = {"cuda", "hip", "cui", "hipi"};
-  if (!IsCLMode() || ValidXArgs.contains(LastXArg)) {
+  {
     Arg *LastXArg = Args.getLastArgNoClaim(options::OPT_x);
     Arg *LastInputArg = Args.getLastArgNoClaim(options::OPT_INPUT);
     if (LastXArg && LastInputArg &&
         LastInputArg->getIndex() < LastXArg->getIndex())
       Diag(clang::diag::warn_drv_unused_x) << LastXArg->getValue();
-  } else {
-    // In CL mode suggest /TC or /TP since -x doesn't make sense if passed via
-    // /clang:.
-    if (auto *A = Args.getLastArg(options::OPT_x))
-      Diag(diag::err_drv_unsupported_opt_with_suggestion)
-          << A->getAsString(Args) << "/TC' or '/TP";
   }
 
   for (Arg *A : Args) {
diff --git a/clang/test/Driver/x-args.c b/clang/test/Driver/x-args.c
index 17bb5d99404dae..b49f474babf0fa 100644
--- a/clang/test/Driver/x-args.c
+++ b/clang/test/Driver/x-args.c
@@ -5,7 +5,3 @@
 // RUN: %clang -fsyntax-only -xc %s -xc++ -fsyntax-only 2>&1 | FileCheck %s
 // RUN: %clang -fsyntax-only %s -xc %s -xc++ -fsyntax-only 2>&1 | FileCheck %s
 // CHECK: '-x c++' after last input file has no effect
-
-// RUN: not %clang_cl /WX /clang:-xc /clang:-E /clang:-dM -- %s 2>&1 | FileCheck --implicit-check-not="error:" -check-prefix=CL %s
-// RUN: not %clang_cl /TC /WX /clang:-xc /clang:-E /clang:-dM -- %s 2>&1 | FileCheck --implicit-check-not="error:" -check-prefix=CL %s
-// CL: error: unsupported option '-x c'; did you mean '/TC' or '/TP'?