Add x86 multilib toolchain support

.github/workflows/build.yml

@@ -97,8 +97,14 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v4
 
-      - name: Apply x86 patch
-        run: patch -p1 -i src/variant-x86.patch
+      - name: Load x86 build args
+        id: variant
+        run: |
+          {
+            echo 'args<<EOF'
+            cat src/variant-x86.args
+            echo 'EOF'
+          } >> "$GITHUB_OUTPUT"
 
       - name: Generate archive name and version string
         id: filename
@@ -112,6 +118,7 @@ jobs:
         uses: docker/build-push-action@v7
         with:
           context: .
+          build-args: ${{ steps.variant.outputs.args }}
           tags: w64devkit:${{ env.ARCH }}
           load: true
           cache-from: type=gha,scope=w64devkit-${{ env.ARCH }}
@@ -175,13 +182,20 @@ jobs:
             > w64devkit-x64-${{ steps.filename.outputs.version }}.7z.exe
           ls -lh w64devkit-x64-${{ steps.filename.outputs.version }}.7z.exe
 
-      - name: Apply x86 patch
-        run: patch -p1 -i src/variant-x86.patch
+      - name: Load x86 build args
+        id: variant
+        run: |
+          {
+            echo 'args<<EOF'
+            cat src/variant-x86.args
+            echo 'EOF'
+          } >> "$GITHUB_OUTPUT"
 
       - name: Build signed image (x86)
         uses: docker/build-push-action@v7
         with:
           context: .
+          build-args: ${{ steps.variant.outputs.args }}
           target: signed
           tags: w64devkit:x86-signed
           load: true

Dockerfile

@@ -208,8 +208,29 @@ RUN mkdir nsis \
 # Build cross-compiler
 
 FROM dl-cross AS cross
+
+# Variant configuration. The defaults produce the x64 kit, and a variant
+# is a coherent set of overrides (see src/variant-x86.args). Stages
+# before this point are shared between variants.
 ARG ARCH=x86_64-w64-mingw32
-ENV ARCH=$ARCH
+ARG MULTILIB=--enable-multilib
+ARG ARCH_FLAGS=--with-arch-32=pentium4
+# Not named "LIB64": mingw-w64-crt's configure tests whether a shell
+# variable LIB64 (or LIB32) is set, and ARGs leak into the environment
+# of every RUN, which would force the Win64 runtime on regardless of
+# the --{enable,disable}-lib64 flag.
+ARG CRT_LIB64=--enable-lib64
+ARG WINNT_FLAGS=
+ARG MANIFEST_FLAGS=
+ARG BUSYBOX_CONFIG=mingw64u_defconfig
+ARG ZSTD_FLAGS=
+ARG CMAKE_WINNT=
+ARG NSIS_ARCH=amd64
+ENV ARCH=$ARCH \
+    BUSYBOX_CONFIG=$BUSYBOX_CONFIG \
+    ZSTD_FLAGS=$ZSTD_FLAGS \
+    CMAKE_WINNT=$CMAKE_WINNT \
+    NSIS_ARCH=$NSIS_ARCH
 
 WORKDIR /dl/binutils
 COPY src/binutils-*.patch $PREFIX/src/
@@ -241,6 +262,7 @@ RUN printf '#include <crtdefs.h>\n#if __has_include_next(<stddef.h>)\n#include_n
         --prefix=/bootstrap \
         --host=$ARCH \
         --with-default-msvcrt=msvcrt-os \
+        $WINNT_FLAGS \
  && make -j$(nproc) \
  && make install
 
@@ -253,6 +275,8 @@ RUN cat $PREFIX/src/gcc-*.patch | patch -d/dl/gcc -p1 \
  && /dl/gcc/configure \
         --prefix=/bootstrap \
         --with-sysroot=/bootstrap \
+        $ARCH_FLAGS \
+        $MULTILIB \
         --target=$ARCH \
         --enable-static \
         --disable-shared \
@@ -266,7 +290,6 @@ RUN cat $PREFIX/src/gcc-*.patch | patch -d/dl/gcc -p1 \
         --disable-dependency-tracking \
         --disable-nls \
         --disable-lto \
-        --disable-multilib \
         CFLAGS_FOR_TARGET="-O2" \
         CXXFLAGS_FOR_TARGET="-O2" \
         LDFLAGS_FOR_TARGET="-s" \
@@ -285,7 +308,16 @@ RUN mkdir -p $PREFIX/lib \
  && ln $PREFIX/lib/libmemory.a /bootstrap/lib/ \
  && CC=$ARCH-gcc AR=$ARCH-ar DESTDIR=$PREFIX/lib/ \
         sh $PREFIX/src/libchkstk.S \
- && ln $PREFIX/lib/libchkstk.a /bootstrap/lib/
+ && ln $PREFIX/lib/libchkstk.a /bootstrap/lib/ \
+ && if [ "$MULTILIB" = --enable-multilib ]; then \
+        mkdir -p $PREFIX/lib32 /bootstrap/lib32 \
+     && CC="$ARCH-gcc -m32" AR=$ARCH-ar DESTDIR=$PREFIX/lib32/ \
+            sh $PREFIX/src/libmemory.c \
+     && ln $PREFIX/lib32/libmemory.a /bootstrap/lib32/ \
+     && CC="$ARCH-gcc -m32" AR=$ARCH-ar DESTDIR=$PREFIX/lib32/ \
+            sh $PREFIX/src/libchkstk.S \
+     && ln $PREFIX/lib32/libchkstk.a /bootstrap/lib32/ ; \
+    fi
 
 WORKDIR /x-mingw-crt
 RUN /dl/mingw/mingw-w64-crt/configure \
@@ -294,8 +326,8 @@ RUN /dl/mingw/mingw-w64-crt/configure \
         --host=$ARCH \
         --with-default-msvcrt=msvcrt-os \
         --disable-dependency-tracking \
-        --disable-lib32 \
-        --enable-lib64 \
+        --enable-lib32 \
+        $CRT_LIB64 \
         CFLAGS="-O2" \
         LDFLAGS="-s" \
  && make -j$(nproc) \
@@ -313,6 +345,22 @@ RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
  && make -j$(nproc) \
  && make install
 
+WORKDIR /x-winpthreads32
+RUN if [ "$MULTILIB" = --enable-multilib ]; then \
+        /dl/mingw/mingw-w64-libraries/winpthreads/configure \
+            --prefix=/bootstrap \
+            --libdir=/bootstrap/lib32 \
+            --with-sysroot=/bootstrap \
+            --host=$ARCH \
+            --enable-static \
+            --disable-shared \
+            CC="$ARCH-gcc -m32" \
+            CFLAGS="-O2" \
+            LDFLAGS="-s" \
+     && make -j$(nproc) \
+     && make install ; \
+    fi
+
 WORKDIR /x-gcc
 RUN make -j$(nproc) \
  && make install
@@ -331,7 +379,7 @@ RUN /dl/binutils/configure \
         LDFLAGS="-s" \
  && make MAKEINFO=true tooldir=$PREFIX -j$(nproc) \
  && make MAKEINFO=true tooldir=$PREFIX install \
- && rm $PREFIX/bin/elfedit.exe $PREFIX/bin/readelf.exe
+ && rm $PREFIX/bin/dllwrap.exe $PREFIX/bin/elfedit.exe $PREFIX/bin/readelf.exe
 
 WORKDIR /gmp
 RUN /dl/gmp/configure \
@@ -388,6 +436,7 @@ RUN /dl/mingw/mingw-w64-headers/configure \
         --host=$ARCH \
         --enable-idl \
         --with-default-msvcrt=msvcrt-os \
+        $WINNT_FLAGS \
  && make -j$(nproc) \
  && make install
 
@@ -398,8 +447,8 @@ RUN /dl/mingw/mingw-w64-crt/configure \
         --host=$ARCH \
         --with-default-msvcrt=msvcrt-os \
         --disable-dependency-tracking \
-        --disable-lib32 \
-        --enable-lib64 \
+        --enable-lib32 \
+        $CRT_LIB64 \
         CFLAGS="-O2" \
         LDFLAGS="-s" \
  && make -j$(nproc) \
@@ -409,7 +458,13 @@ COPY src/threads.c $PREFIX/src/
 COPY src/threads.h $PREFIX/include/
 RUN $ARCH-gcc -c -Oz -I$PREFIX/include/ \
         -ffunction-sections -Wa,--no-pad-sections $PREFIX/src/threads.c \
- && $ARCH-ar r $PREFIX/lib/libmingwex.a threads.o
+ && $ARCH-ar r $PREFIX/lib/libmingwex.a threads.o \
+ && if [ "$MULTILIB" = --enable-multilib ]; then \
+        $ARCH-gcc -m32 -c -Oz -I$PREFIX/include/ \
+            -ffunction-sections -Wa,--no-pad-sections \
+            -o threads32.o $PREFIX/src/threads.c \
+     && $ARCH-ar r $PREFIX/lib32/libmingwex.a threads32.o ; \
+    fi
 
 WORKDIR /winpthreads
 RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
@@ -423,13 +478,31 @@ RUN /dl/mingw/mingw-w64-libraries/winpthreads/configure \
  && make -j$(nproc) \
  && make install
 
+WORKDIR /winpthreads32
+RUN if [ "$MULTILIB" = --enable-multilib ]; then \
+        /dl/mingw/mingw-w64-libraries/winpthreads/configure \
+            --prefix=$PREFIX \
+            --libdir=$PREFIX/lib32 \
+            --with-sysroot=$PREFIX \
+            --host=$ARCH \
+            --enable-static \
+            --disable-shared \
+            CC="$ARCH-gcc -m32" \
+            CFLAGS="-O2" \
+            LDFLAGS="-s" \
+     && make -j$(nproc) \
+     && make install ; \
+    fi
+
 WORKDIR /gcc
 COPY src/crossgcc-*.patch $PREFIX/src/
 RUN cat $PREFIX/src/crossgcc-*.patch | patch -d/dl/gcc -p1 \
  && /dl/gcc/configure \
         --prefix=$PREFIX \
         --with-sysroot=$PREFIX \
         --with-native-system-header-dir=/include \
+        $ARCH_FLAGS \
+        $MULTILIB \
         --target=$ARCH \
         --host=$ARCH \
         --enable-static \
@@ -446,9 +519,9 @@ RUN cat $PREFIX/src/crossgcc-*.patch | patch -d/dl/gcc -p1 \
         --disable-libstdcxx-verbose \
         --disable-dependency-tracking \
         --disable-lto \
-        --disable-multilib \
         --disable-nls \
         --disable-win32-registry \
+        $MANIFEST_FLAGS \
         --enable-mingw-wildcard \
         CFLAGS_FOR_TARGET="-O2" \
         CXXFLAGS_FOR_TARGET="-O2" \
@@ -475,7 +548,7 @@ RUN $ARCH-gcc -DEXE=gcc.exe -DCMD=cc \
  && $ARCH-gcc -DEXE=gcc.exe -DCMD="cc -ansi" \
         -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
         -o $PREFIX/bin/c89.exe $PREFIX/src/alias.c -lkernel32 \
- && printf '%s\n' addr2line ar as c++filt cpp dlltool dllwrap g++ \
+ && printf '%s\n' addr2line ar as c++filt cpp dlltool g++ \
       gcc gcc-ar gcc-nm gcc-ranlib gcov gcov-dump gcov-tool gendef gfortran \
       ld nm objcopy objdump ranlib size strings strip uuidgen widl \
       windmc windres \
@@ -485,6 +558,49 @@ RUN $ARCH-gcc -DEXE=gcc.exe -DCMD=cc \
             -Wl,--gc-sections -s -nostdlib \
             -o $PREFIX/bin/$ARCH-{}.exe $PREFIX/src/alias.c -lkernel32
 
+# Create i686 tool aliases
+RUN if [ "$MULTILIB" = --enable-multilib ]; then \
+    printf '%s\n' addr2line ar c++filt gcc-ar gcc-nm gcc-ranlib gcov \
+        gcov-dump gcov-tool gendef nm objcopy objdump ranlib size strings \
+        strip uuidgen windmc \
+    | xargs -I{} -P$(nproc) \
+          $ARCH-gcc -DEXE={}.exe -DCMD=i686-w64-mingw32-{} \
+            -Oz -fno-asynchronous-unwind-tables \
+            -Wl,--gc-sections -s -nostdlib \
+            -o $PREFIX/bin/i686-w64-mingw32-{}.exe \
+            $PREFIX/src/alias.c -lkernel32 \
+ && printf '%s\n' cpp gcc g++ gfortran \
+    | xargs -I{} -P$(nproc) \
+          $ARCH-gcc -DEXE={}.exe -DCMD="i686-w64-mingw32-{} -m32" \
+            -Oz -fno-asynchronous-unwind-tables \
+            -Wl,--gc-sections -s -nostdlib \
+            -o $PREFIX/bin/i686-w64-mingw32-{}.exe \
+            $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=as.exe -DCMD="i686-w64-mingw32-as --32" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-as.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=ld.exe -DCMD="i686-w64-mingw32-ld -m i386pe" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-ld.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=dlltool.exe \
+        -DCMD="i686-w64-mingw32-dlltool -m i386 --as-flags=--32" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-dlltool.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=widl.exe \
+        -DCMD="i686-w64-mingw32-widl --win32" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-widl.exe \
+        $PREFIX/src/alias.c -lkernel32 \
+ && $ARCH-gcc -DEXE=windres.exe \
+        -DCMD="i686-w64-mingw32-windres --target=pe-i386" \
+        -Oz -fno-asynchronous-unwind-tables -Wl,--gc-sections -s -nostdlib \
+        -o $PREFIX/bin/i686-w64-mingw32-windres.exe \
+        $PREFIX/src/alias.c -lkernel32 ; \
+    fi
+
 # Build some extra development tools
 
 FROM cross AS build-gendef
@@ -598,7 +714,7 @@ COPY --from=dl-busybox /dl/ /dl/
 WORKDIR /dl/busybox
 COPY src/busybox-* $PREFIX/src/
 RUN cat $PREFIX/src/busybox-*.patch | patch -p1 \
- && make mingw64u_defconfig \
+ && make $BUSYBOX_CONFIG \
  && sed -ri 's/^(CONFIG_AR)=y/\1=n/' .config \
  && sed -ri 's/^(CONFIG_ASCII)=y/\1=n/' .config \
  && sed -ri -e 's/^(CONFIG_BASH_IS_ASH)=y/\1=n/' \
@@ -693,7 +809,7 @@ RUN make -j$(nproc) CC=$ARCH-gcc AR=$ARCH-ar CFLAGS="-O2" libzstd.a \
 
 WORKDIR /dl/zstd
 RUN make -j$(nproc) -C programs zstd \
-        CC=$ARCH-gcc CFLAGS="-O2" LDFLAGS="-s" EXT=.exe \
+        CC=$ARCH-gcc CFLAGS="-O2" LDFLAGS="-s" EXT=.exe $ZSTD_FLAGS \
  && mkdir -p /out/bin \
  && cp programs/zstd.exe /out/bin/ \
  && $ARCH-gcc -DEXE=zstd.exe -DCMD=unzstd \
@@ -788,7 +904,11 @@ COPY --from=build-pdcurses /deps/include/curses.h /deps/include/
 WORKDIR /cmake
 COPY src/cmake-*.patch $PREFIX/src/
 RUN cat $PREFIX/src/cmake-*.patch | patch -d/dl/cmake -p1 \
- && cmake -DCMAKE_BUILD_TYPE=Release \
+ && if [ -n "$CMAKE_WINNT" ]; then \
+        set -- -DCMAKE_C_FLAGS="-O2 -D_WIN32_WINNT=$CMAKE_WINNT" \
+               -DCMAKE_CXX_FLAGS="-O2 -D_WIN32_WINNT=$CMAKE_WINNT" ; \
+    fi \
+ && cmake "$@" -DCMAKE_BUILD_TYPE=Release \
         -DCMAKE_SYSTEM_NAME=Windows \
         -DCMAKE_C_COMPILER=$ARCH-gcc \
         -DCMAKE_CXX_COMPILER=$ARCH-g++ \
@@ -853,7 +973,7 @@ RUN sed -i 's/\r$//' Source/build.cpp \
  && cat $PREFIX/src/nsis-*.patch | patch -p1 \
  && scons -j$(nproc) \
         XGCC_W32_PREFIX=$ARCH- \
-        TARGET_ARCH=amd64 \
+        TARGET_ARCH=$NSIS_ARCH \
         PREFIX=$PREFIX \
         PREFIX_BIN=$PREFIX/share/nsis/bin \
         PREFIX_DATA=$PREFIX/share/nsis \

multibuild.sh

@@ -53,7 +53,11 @@ cleanup() {
 trap cleanup EXIT
 
 for variant in $arch; do
-    if [ -e "src/variant-$variant.patch" ]; then
+    if [ -e "src/variant-$variant.args" ]; then
+        $dryrun docker build \
+            $(sed 's/^/--build-arg /' "src/variant-$variant.args") \
+            -t $target .
+    elif [ -e "src/variant-$variant.patch" ]; then
         tmp=$(mktemp -d)
         $dryrun cp Dockerfile "$tmp/"
         $dryrun patch "$tmp/Dockerfile" "src/variant-$variant.patch"

src/crossgcc-i686-dumpmachine.patch

@@ -0,0 +1,23 @@
+Report the emulated i686 target from i686 driver aliases
+
+The multilib compiler is configured for x86_64, so -m32 does not change
+-dumpmachine.  The i686 aliases present themselves as target-prefixed
+compilers, and target-detecting build systems expect that prefix and
+-dumpmachine to agree.  Preserve normal multilib behavior for every other
+invocation name.
+--- a/gcc/gcc.cc
++++ b/gcc/gcc.cc
+@@ -4249,6 +4249,13 @@ driver_handle_option (struct gcc_options *opts,
+       exit (0);
+
+     case OPT_dumpmachine:
++#ifdef __MINGW32__
++      if (startswith (progname, "i686-w64-mingw32-"))
++	{
++	  printf ("i686-w64-mingw32\n");
++	  exit (0);
++	}
++#endif
+       printf ("%s\n", spec_machine);
+       exit (0);
+

src/mingw-default-win32-winnt.patch

@@ -0,0 +1,19 @@
+headers: default 32-bit x86 to Windows XP
+
+The x86_64 multilib toolchain shares one header tree between its 64-bit
+and 32-bit targets. Keep the configured mingw-w64 default for x86_64 and
+other architectures, but preserve w64devkit's Windows XP default when
+the compiler targets i686. An explicit user definition still takes
+precedence through the existing outer guard.
+
+--- a/mingw-w64-headers/crt/_mingw.h.in
++++ b/mingw-w64-headers/crt/_mingw.h.in
+@@ -255,3 +255,7 @@
+ #ifndef _WIN32_WINNT
+-#define _WIN32_WINNT @DEFAULT_WIN32_WINNT@
++# if defined(__i386__)
++#  define _WIN32_WINNT 0x0501
++# else
++#  define _WIN32_WINNT @DEFAULT_WIN32_WINNT@
++# endif
+ #endif