[clang] [Clang] Only allow `clang` arguments to `-Xarch` (PR #126101)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 updated https://github.com/llvm/llvm-project/pull/126101

>From de568616e5f493b6bc8bd8e3a8080108599a6051 Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Thu, 6 Feb 2025 11:37:09 -0600
Subject: [PATCH] [Clang] Only allow `clang` arguments to `-Xarch`

Summary:
Currently the `-Xarch` argument needs to re-parse the option, which goes
through every single registered argument. This causes errors when trying
to pass `-O1` through it because it thinks it's a DXC option. This patch
changes the behavior to only allow `clang` options. Concievably we could
detect the driver mode to make this more robust, but I don't know if
there are other users for this.

Fixes: https://github.com/llvm/llvm-project/issues/110325
---
 clang/lib/Driver/ToolChain.cpp | 3 ++-
 clang/test/Driver/Xarch.c      | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index c25d1b6be14b50d..56bc500da66b9f5 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -1651,7 +1651,8 @@ void ToolChain::TranslateXarchArgs(
   const InputArgList &BaseArgs = Args.getBaseArgs();
   unsigned Index = BaseArgs.MakeIndex(A->getValue(ValuePos));
   unsigned Prev = Index;
-  std::unique_ptr<llvm::opt::Arg> XarchArg(Opts.ParseOneArg(Args, Index));
+  std::unique_ptr<llvm::opt::Arg> XarchArg(Opts.ParseOneArg(
+      Args, Index, llvm::opt::Visibility(clang::driver::options::ClangOption)));
 
   // If the argument parsing failed or more than one argument was
   // consumed, the -Xarch_ argument's parameter tried to consume
diff --git a/clang/test/Driver/Xarch.c b/clang/test/Driver/Xarch.c
index f35e2926f9c8d5f..95bd0c502ddb31b 100644
--- a/clang/test/Driver/Xarch.c
+++ b/clang/test/Driver/Xarch.c
@@ -18,3 +18,7 @@
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -Xarch_x86_64 -Wl,foo %s -### 2>&1 | FileCheck -check-prefix=LINKER %s
 // LINKER: "foo"
+
+// RUN: %clang -target x86_64-unknown-linux-gnu -Xarch_x86_64 -O1 %s -S -### 2>&1 | FileCheck -check-prefix=O1ONCE %s
+// O1ONCE: "-O1"
+// O1ONCE-NOT: "-O1"