[llvm-windres] Pass user preprocessor arguments before the input filename (#75389)

If passing the windres option --preprocessor, the default arguments "-E
-xc -DRC_INVOKED" aren't passed. If these are passed explicitly by the
user via --preprocessor-arg instead, we need to make sure that "-xc" is
passed before the input filename, as this compiler/preprocessor option
only has an effect on input files that follow it.

This fixes one of the issues with llvm-windres observed in
msys2/MINGW-packages#19157.

Author: mstorsjo

llvm/test/tools/llvm-rc/preproc.test

@@ -1,3 +1,3 @@
 ; RUN: llvm-rc -### -i%p "-DFOO1=\"foo bar\"" -UFOO2 -D FOO3 -- %p/Inputs/empty.rc | FileCheck %s
 
-; CHECK: {{^}} "clang" "--driver-mode=gcc" "-target" "{{.*}}-pc-windows-msvc-coff" "-E" "-xc" "-DRC_INVOKED" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc" "-I" "{{.*}}" "-D" "FOO1=\"foo bar\"" "-U" "FOO2" "-D" "FOO3"{{$}}
+; CHECK: {{^}} "clang" "--driver-mode=gcc" "-target" "{{.*}}-pc-windows-msvc-coff" "-E" "-xc" "-DRC_INVOKED" "-I" "{{.*}}" "-D" "FOO1=\"foo bar\"" "-U" "FOO2" "-D" "FOO3" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}

llvm/test/tools/llvm-rc/windres-preproc.test

@@ -5,6 +5,6 @@
 
 ; RUN: llvm-windres -### --include-dir %p/incdir1 --include %p/incdir2 "-DFOO1=\\\"foo bar\\\"" -UFOO2 -D FOO3 --preprocessor-arg "-DFOO4=\\\"baz baz\\\"" -DFOO5=\"bar\" %p/Inputs/empty.rc %t.res | FileCheck %s --check-prefix=CHECK1
 ; RUN: llvm-windres -### --include-dir %p/incdir1 --include %p/incdir2 "-DFOO1=\"foo bar\"" -UFOO2 -D FOO3 --preprocessor-arg "-DFOO4=\"baz baz\"" "-DFOO5=bar" %p/Inputs/empty.rc %t.res --use-temp-file | FileCheck %s --check-prefix=CHECK1
-; CHECK1: {{^}} "clang" "--driver-mode=gcc" "-target" "{{.*}}-{{.*}}{{mingw32|windows-gnu}}" "-E" "-xc" "-DRC_INVOKED" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc" "-I" "{{.*}}incdir1" "-I" "{{.*}}incdir2" "-D" "FOO1=\"foo bar\"" "-U" "FOO2" "-D" "FOO3" "-DFOO4=\"baz baz\"" "-D" "FOO5=bar"{{$}}
+; CHECK1: {{^}} "clang" "--driver-mode=gcc" "-target" "{{.*}}-{{.*}}{{mingw32|windows-gnu}}" "-E" "-xc" "-DRC_INVOKED" "-I" "{{.*}}incdir1" "-I" "{{.*}}incdir2" "-D" "FOO1=\"foo bar\"" "-U" "FOO2" "-D" "FOO3" "-DFOO4=\"baz baz\"" "-D" "FOO5=bar" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}
 ; RUN: llvm-windres -### --preprocessor "i686-w64-mingw32-gcc -E -DFOO=\\\"foo\\ bar\\\"" %p/Inputs/empty.rc %t.res | FileCheck %s --check-prefix=CHECK2
 ; CHECK2: {{^}} "i686-w64-mingw32-gcc" "-E" "-DFOO=\"foo bar\"" "{{.*}}empty.rc" "-o" "{{.*}}preproc-{{.*}}.rc"{{$}}

llvm/tools/llvm-rc/llvm-rc.cpp

@@ -253,11 +253,11 @@ void preprocess(StringRef Src, StringRef Dst, const RcOptions &Opts,
     for (const auto &S : Opts.PreprocessCmd)
       Args.push_back(S);
   }
+  for (const auto &S : Opts.PreprocessArgs)
+    Args.push_back(S);
   Args.push_back(Src);
   Args.push_back("-o");
   Args.push_back(Dst);
-  for (const auto &S : Opts.PreprocessArgs)
-    Args.push_back(S);
   if (Opts.PrintCmdAndExit || Opts.BeVerbose) {
     for (const auto &A : Args) {
       outs() << " ";