Hack to make rust buildable for Clang prefixes

mingw-w64-rust/0007-clang-subsystem.patch

@@ -0,0 +1,83 @@
+diff -urN rustc-1.52.1-src.orig/compiler/rustc_target/src/spec/windows_gnu_base.rs rustc-1.52.1-src/compiler/rustc_target/src/spec/windows_gnu_base.rs
+--- rustc-1.52.1-src.orig/compiler/rustc_target/src/spec/windows_gnu_base.rs	2021-05-09 04:52:39.000000000 +0200
++++ rustc-1.52.1-src/compiler/rustc_target/src/spec/windows_gnu_base.rs	2021-06-06 22:12:33.367953300 +0200
+@@ -18,34 +18,13 @@
+         ],
+     );
+
+-    let mut late_link_args = LinkArgs::new();
+     let mut late_link_args_dynamic = LinkArgs::new();
+     let mut late_link_args_static = LinkArgs::new();
+-    // Order of `late_link_args*` was found through trial and error to work with various
+-    // mingw-w64 versions (not tested on the CI). It's expected to change from time to time.
+-    let mingw_libs = vec![
+-        "-lmsvcrt".to_string(),
+-        "-lmingwex".to_string(),
+-        "-lmingw32".to_string(),
+-        "-lgcc".to_string(), // alas, mingw* libraries above depend on libgcc
+-        // mingw's msvcrt is a weird hybrid import library and static library.
+-        // And it seems that the linker fails to use import symbols from msvcrt
+-        // that are required from functions in msvcrt in certain cases. For example
+-        // `_fmode` that is used by an implementation of `__p__fmode` in x86_64.
+-        // The library is purposely listed twice to fix that.
+-        //
+-        // See https://github.com/rust-lang/rust/pull/47483 for some more details.
+-        "-lmsvcrt".to_string(),
+-        "-luser32".to_string(),
+-        "-lkernel32".to_string(),
+-    ];
+-    late_link_args.insert(LinkerFlavor::Gcc, mingw_libs.clone());
+-    late_link_args.insert(LinkerFlavor::Lld(LldFlavor::Ld), mingw_libs);
+     let dynamic_unwind_libs = vec![
+         // If any of our crates are dynamically linked then we need to use
+         // the shared libgcc_s-dw2-1.dll. This is required to support
+         // unwinding across DLL boundaries.
+-        "-lgcc_s".to_string(),
++        "-l:libunwind.dll.a".to_string(),
+     ];
+     late_link_args_dynamic.insert(LinkerFlavor::Gcc, dynamic_unwind_libs.clone());
+     late_link_args_dynamic.insert(LinkerFlavor::Lld(LldFlavor::Ld), dynamic_unwind_libs);
+@@ -55,8 +34,7 @@
+         // binaries to be redistributed without the libgcc_s-dw2-1.dll
+         // dependency, but unfortunately break unwinding across DLL
+         // boundaries when unwinding across FFI boundaries.
+-        "-lgcc_eh".to_string(),
+-        "-l:libpthread.a".to_string(),
++        "-l:libunwind.a".to_string(),
+     ];
+     late_link_args_static.insert(LinkerFlavor::Gcc, static_unwind_libs.clone());
+     late_link_args_static.insert(LinkerFlavor::Lld(LldFlavor::Ld), static_unwind_libs);
+@@ -66,7 +44,8 @@
+         env: "gnu".to_string(),
+         vendor: "pc".to_string(),
+         // FIXME(#13846) this should be enabled for windows
+-        function_sections: false,
++        function_sections: true,
++        no_default_libraries: false,
+         linker: Some("gcc".to_string()),
+         dynamic_linking: true,
+         executables: true,
+@@ -84,7 +63,6 @@
+         pre_link_objects_fallback: crt_objects::pre_mingw_fallback(),
+         post_link_objects_fallback: crt_objects::post_mingw_fallback(),
+         crt_objects_fallback: Some(CrtObjectsFallback::Mingw),
+-        late_link_args,
+         late_link_args_dynamic,
+         late_link_args_static,
+         abi_return_struct_as_int: true,
+diff -urN rustc-1.53.0-src/src/bootstrap/bootstrap.py.orig rustc-1.53.0-src/src/bootstrap/bootstrap.py
+--- rustc-1.53.0-src/src/bootstrap/bootstrap.py.orig    2021-07-03 13:57:23.756296000 +0200
++++ rustc-1.53.0-src/src/bootstrap/bootstrap.py 2021-07-03 13:58:41.037817900 +0200
+@@ -425,6 +425,12 @@
+             with output(self.rustc_stamp(stage0)) as rust_stamp:
+                 rust_stamp.write(key)
+
++            gcc_libs_hack = os.environ.get('GCC_LIBS_HACK')
++            gcc_libs_hack_dest = '{}/rustlib/{}/lib'.format(lib_dir, self.build)
++            shutil.copy(gcc_libs_hack + '/libgcc.a', gcc_libs_hack_dest)
++            shutil.copy(gcc_libs_hack + '/libgcc_eh.a', gcc_libs_hack_dest)
++            shutil.copy(gcc_libs_hack + '/libgcc_s.a', gcc_libs_hack_dest)
++
+         if self.rustfmt() and self.rustfmt().startswith(bin_root) and (
+             not os.path.exists(self.rustfmt())
+             or self.program_out_of_date(self.rustfmt_stamp(), self.rustfmt_channel)

mingw-w64-rust/PKGBUILD

@@ -35,13 +35,17 @@ source=("https://static.rust-lang.org/dist/${_realname}c-${pkgver}-src.tar.gz"
         "0001-add-missing-libs.patch"
         "0004-unbundle-gcc.patch"
         "0005-win32-config.patch"
-        "0006-Update-cc.patch")
+        "0006-Update-cc.patch"
+        "0006-Update-cc.patch"
+        "0007-clang-subsystem.patch")
 sha256sums=('5cf7ca39a10f6bf4e0b0bd15e3b9a61ce721f301e12d148262e5ba968ab825b9'
             'bd63b990d2c1626acb87d5ea534c3d82fc4daddb5f784a83053be7b162327445'
             'c706841ace2ef76fd1004b9c0486ea9ef7d99073c5ce2884e4c97fa4a7beab25'
             '6cc3234644768e24824e455d6304585c717ae25aa53ebf9cf1f1dea87bf869b7'
             'c4e5ffeef84296d39c3e3e8f807fc8b33ce786b1e4edb21eef26b053586aca27'
-            'dd8f785138a78398c486fe60237833d1c6a84be5128ad6b3210c135dda258497')
+            'dd8f785138a78398c486fe60237833d1c6a84be5128ad6b3210c135dda258497'
+            'dd8f785138a78398c486fe60237833d1c6a84be5128ad6b3210c135dda258497'
+            '9e2e2eb9c0684f329b1ce6598fcb66727abf84121087b24670a9cfc44a514888')
 #validpgpkeys=('108F66205EAEB0AAA8DD5E1C85AB96E6FA1BE5FE') # Rust Language (Tag and Release Signing Key) <[email protected]>
 noextract=(${_realname}c-${pkgver}-src.tar.gz)
 
@@ -55,12 +59,27 @@ prepare() {
   patch -p1 -i "${srcdir}/0004-unbundle-gcc.patch"
   patch -p1 -i "${srcdir}/0005-win32-config.patch"
   patch -p1 -i "${srcdir}/0006-Update-cc.patch"
+
+  if [[ $MINGW_PACKAGE_PREFIX == *-clang-* ]]; then
+    patch -p1 -i "${srcdir}/0007-clang-subsystem.patch"
+  fi
 }
 
 build() {
   [[ -d "${srcdir}/${CARCH}" ]] && rm -rf "${srcdir}/${CARCH}"
   mkdir -p "${srcdir}/${CARCH}" && cd "${srcdir}/${CARCH}"
 
+
+  # The ultimate hack to let the bootstrap compiler use libgcc* libs
+  if [[ $MINGW_PACKAGE_PREFIX == *-clang-* ]]; then
+    export GCC_LIBS_HACK="$(cygpath -am build/missing-libs-hack)"
+    mkdir -p "${GCC_LIBS_HACK}"
+    cp "$(cygpath -u $(clang -print-libgcc-file-name))" "${GCC_LIBS_HACK}/libgcc.a"
+    cp "${MINGW_PREFIX}/lib/libunwind.a" "${GCC_LIBS_HACK}/libgcc_eh.a"
+    cp "${MINGW_PREFIX}/lib/libunwind.dll.a" "${GCC_LIBS_HACK}/libgcc_s.a"
+    export RUSTFLAGS_BOOTSTRAP="-C link-arg=-L$(cygpath -am build/missing-libs-hack)"
+  fi
+
   #We have to do the following because rust doesn't count x86_64-w64-mingw32 as a target triple
   OSTYPE="$CARCH-pc-windows-gnu"
 
@@ -88,7 +107,7 @@ build() {
   DEP_NGHTTP_ROOT=${MINGW_PREFIX} \
   DEP_OPENSSL_ROOT=${MINGW_PREFIX} \
   DEP_Z_ROOT=${MINGW_PREFIX} \
-  ${MINGW_PREFIX}/bin/python ../${_realname}c-${pkgver}-src/x.py build --verbose --stage 2 -j "$(nproc)"
+  ${MINGW_PREFIX}/bin/python ../${_realname}c-${pkgver}-src/x.py build --verbose --stage 2
 
   #create the install at a temporary directory
   DEP_NGHTTP_ROOT=${MINGW_PREFIX} \