[Driver][MinGW] Allow using clang driver to link ARM64X PEs. (#148064)

Similar to how clang-cl driver does it, make it possible to build arm64x
binaries with a mingw-style invocation.

Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>

Author: WhatAmISupposedToPutHere

clang/lib/Driver/ToolChains/MinGW.cpp

@@ -132,7 +132,9 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("thumb2pe");
     break;
   case llvm::Triple::aarch64:
-    if (TC.getEffectiveTriple().isWindowsArm64EC())
+    if (Args.hasArg(options::OPT_marm64x))
+      CmdArgs.push_back("arm64xpe");
+    else if (TC.getEffectiveTriple().isWindowsArm64EC())
       CmdArgs.push_back("arm64ecpe");
     else
       CmdArgs.push_back("arm64pe");

clang/test/Driver/mingw.cpp

@@ -85,6 +85,10 @@
 // RUN:   | FileCheck %s --check-prefix CHECK_MINGW_EC_LINK
 // CHECK_MINGW_EC_LINK: "-m" "arm64ecpe"
 
+// RUN: %clang --target=aarch64-windows-gnu -marm64x -### -o /dev/null %s 2>&1 \
+// RUN:   | FileCheck %s --check-prefix CHECK_MINGW_A64X_LINK
+// CHECK_MINGW_A64X_LINK: "-m" "arm64xpe"
+
 // RUN: %clang --target=mipsel-windows-gnu -### -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK_MINGW_MIPSPE
 // CHECK_MINGW_MIPSPE: "-m" "mipspe"