[clang] [MinGW] Pass --no-demangle through to the mingw linker

Clang has custom handling of --no-demangle, where it is removed
from the input -Wl and -Xlinker options, and readded specifically
by the drivers where it's known to be supported.

Both ld.bfd and lld support the --no-demangle option. This handles
the option in the same way as in ToolChains/Gnu.cpp.

Differential Revision: https://reviews.llvm.org/D114064

clang/lib/Driver/ToolChains/MinGW.cpp

@@ -164,6 +164,9 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
     CmdArgs.push_back("--enable-auto-image-base");
   }
 
+  if (Args.hasArg(options::OPT_Z_Xlinker__no_demangle))
+    CmdArgs.push_back("--no-demangle");
+
   CmdArgs.push_back("-o");
   const char *OutputFile = Output.getFilename();
   // GCC implicitly adds an .exe extension if it is given an output file name

clang/test/Driver/Xlinker-args.c

@@ -12,6 +12,11 @@
 // RUN:   -Wl,two,--no-demangle,three -Xlinker four -z five -r %s 2> %t
 // RUN: FileCheck -check-prefix=LINUX < %t %s
 
+/// Check that --no-demangle gets forwarded to the mingw linker
+// RUN: %clang -target x86_64-w64-mingw32 -### \
+// RUN:   -Wl,--no-demangle %s 2> %t
+// RUN: FileCheck -check-prefix=MINGW < %t %s
+
 // RUN: %clang -target powerpc-unknown-aix -### \
 // RUN:   -b one -b two %s 2> %t
 // RUN: FileCheck -check-prefix=AIX < %t %s
@@ -23,6 +28,7 @@
 // DARWIN-NOT: --no-demangle
 // DARWIN: "one" "two" "three" "four" "-z" "five" "-r"
 // LINUX: "--no-demangle" "-e" "_start" "one" "two" "three" "four" "-z" "five" "-r" {{.*}} "-T" "a.lds"
+// MINGW: "--no-demangle"
 // AIX: "-b" "one" "-b" "two"
 // NOT-AIX: error: unsupported option '-b' for target 'powerpc-unknown-linux'