From 63d2e2bb4836ca46b4d48958c253263ec624a638 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Fri, 26 Jul 2024 09:40:42 +0200
Subject: [PATCH] [clang][Driver] Support passing arbitrary args to -cc1as with
 -Xclangas.

Closes #97517.
---
 clang/docs/UsersManual.rst            | 1 +
 clang/include/clang/Driver/Options.td | 8 ++++++++
 clang/lib/Driver/ToolChains/Clang.cpp | 6 ++++++
 clang/test/Driver/Xclangas.s          | 6 ++++++
 4 files changed, 21 insertions(+)
 create mode 100644 clang/test/Driver/Xclangas.s

diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index e9b95739ea2ab5..7f55080321fea7 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -4876,6 +4876,7 @@ Execute ``clang-cl /?`` to see a list of supported options:
       -v                      Show commands to run and use verbose output
       -W<warning>             Enable the specified warning
       -Xclang <arg>           Pass <arg> to the clang compiler
+      -Xclangas <arg>         Pass <arg> to the clang assembler
 
 The /clang: Option
 ^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 26811bf948ae5b..c7839c3941eb97 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1028,10 +1028,18 @@ def Xclang : Separate<["-"], "Xclang">,
   HelpText<"Pass <arg> to clang -cc1">, MetaVarName<"<arg>">,
   Flags<[NoXarchOption]>, Visibility<[ClangOption, CLOption, DXCOption]>,
   Group<CompileOnly_Group>;
+def Xclangas : Separate<["-"], "Xclangas">,
+  HelpText<"Pass <arg> to clang -cc1as">, MetaVarName<"<arg>">,
+  Flags<[NoXarchOption]>, Visibility<[ClangOption, CLOption, DXCOption]>,
+  Group<CompileOnly_Group>;
 def : Joined<["-"], "Xclang=">, Group<CompileOnly_Group>,
   Flags<[NoXarchOption]>, Visibility<[ClangOption, CLOption, DXCOption]>,
   Alias<Xclang>,
   HelpText<"Alias for -Xclang">, MetaVarName<"<arg>">;
+def : Joined<["-"], "Xclangas=">, Group<CompileOnly_Group>,
+  Flags<[NoXarchOption]>, Visibility<[ClangOption, CLOption, DXCOption]>,
+  Alias<Xclangas>,
+  HelpText<"Alias for -Xclangas">, MetaVarName<"<arg>">;
 def Xcuda_fatbinary : Separate<["-"], "Xcuda-fatbinary">,
   HelpText<"Pass <arg> to fatbinary invocation">, MetaVarName<"<arg>">;
 def Xcuda_ptxas : Separate<["-"], "Xcuda-ptxas">,
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 4a94df7d5f42ee..90b8db11c46c65 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -8711,6 +8711,12 @@ void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
   CollectArgsForIntegratedAssembler(C, Args, CmdArgs,
                                     getToolChain().getDriver());
 
+  // Forward -Xclangas arguments to -cc1as
+  for (auto Arg : Args.filtered(options::OPT_Xclangas)) {
+    Arg->claim();
+    CmdArgs.push_back(Arg->getValue());
+  }
+
   Args.AddAllArgs(CmdArgs, options::OPT_mllvm);
 
   if (DebugInfoKind > llvm::codegenoptions::NoDebugInfo && Output.isFilename())
diff --git a/clang/test/Driver/Xclangas.s b/clang/test/Driver/Xclangas.s
new file mode 100644
index 00000000000000..c46391f29baa5c
--- /dev/null
+++ b/clang/test/Driver/Xclangas.s
@@ -0,0 +1,6 @@
+// Check that -Xclangas passes args to -cc1as.
+// RUN: %clang -### -Xclangas -target-feature -Xclangas +v5t %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=ARGS %s
+// ARGS: -cc1as
+// ARGS: -target-feature
+// ARGS: +v5t