go-libwebp

Experimental translation from libwebp to Go source.
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transpile.sh (3013B)

      1 #!/bin/sh
      2 #
      3 # Transpile libwebp to Go with ccgo v4, one file per GOOS/GOARCH.
      4 #
      5 # Requires:
      6 #   ccgo v4                 go install modernc.org/ccgo/v4@latest
      7 #   zig                     darwin headers (replaces osxcross; no Apple SDK needed)
      8 #   x86_64-w64-mingw32-gcc  windows headers
      9 #   aarch64-linux-gnu-gcc   linux/arm64 headers
     10 #
     11 # ccgo v4 supplies target predefines via --goos/--goarch but not target libc
     12 # headers, so each cross target needs a header source. zig covers darwin from
     13 # its bundled any-macos-any headers, which is what removes the osxcross and
     14 # Apple SDK requirement. It does not cover linux: ccgo cannot parse zig's
     15 # generic-glibc bits/types.h, so linux/arm64 still uses a real cross compiler
     16 # and linux/amd64 just uses the host.
     17 
     18 set -eux
     19 
     20 HERE=$(cd "$(dirname "$0")" && pwd)
     21 SRC=$HERE/../c-lib
     22 OUT=$HERE/../lib/transpiled/webp
     23 ZIG=${ZIG:-zig}
     24 ZIGLIB=$($ZIG env | sed -n 's/.*\.lib_dir[ ]*=[ ]*"\([^"]*\)".*/\1/p')
     25 
     26 # dsp.h only enables SIMD when HAVE_CONFIG_H is set together with
     27 # WEBP_HAVE_SSE2, so an empty config.h selects the scalar paths. ccgo has no
     28 # -msse2 to turn off.
     29 INC=$(mktemp -d)
     30 mkdir -p "$INC/src/webp"
     31 # HAVE_BUILTIN_BSWAP* matter: endian_inl_utils.h only probes for the builtins
     32 # when HAVE_CONFIG_H is absent, so without these libwebp falls back to x86
     33 # inline asm, which ccgo turns into a runtime assertion that fires on the
     34 # first lossy decode. A real autotools configure detects these too.
     35 cat > "$INC/src/webp/config.h" <<'CONFIG'
     36 #define HAVE_BUILTIN_BSWAP16 1
     37 #define HAVE_BUILTIN_BSWAP32 1
     38 #define HAVE_BUILTIN_BSWAP64 1
     39 CONFIG
     40 trap 'rm -rf "$INC"' EXIT
     41 
     42 # libwebp declares GetCoeffs as a volatile function pointer; ccgo v4 cannot
     43 # emit a call through one and aborts. Threading is disabled in this build, so
     44 # dropping volatile is safe.
     45 #
     46 # Patched in place rather than in a scratch copy: ccgo resolves
     47 # modernc.org/libc through the module it is run from, so it has to run inside
     48 # this repository.
     49 VP8DEC=$SRC/src/dec/vp8_dec.c
     50 cp "$VP8DEC" "$VP8DEC.orig"
     51 trap 'mv -f "$VP8DEC.orig" "$VP8DEC"; rm -rf "$INC"' EXIT
     52 sed -i 's/^static volatile GetCoeffsFunc GetCoeffs = NULL;/static GetCoeffsFunc GetCoeffs = NULL;/' \
     53     "$VP8DEC"
     54 
     55 transpile() {
     56     goos=$1
     57     goarch=$2
     58     shift 2
     59     echo "=== $goos/$goarch ==="
     60     ( cd "$SRC" && ccgo \
     61         --goos="$goos" --goarch="$goarch" \
     62         --package-name=webp \
     63         -ignore-asm-errors \
     64         "$@" \
     65         -o "$OUT/libwebp_${goos}_${goarch}.go" \
     66         -DNDEBUG -DHAVE_CONFIG_H -I"$INC" -I. \
     67         src/dec/*.c src/enc/*.c src/utils/*.c src/dsp/*.c \
     68         "$HERE/sharpyuv_stub.c" )
     69     gofmt -w "$OUT/libwebp_${goos}_${goarch}.go"
     70 }
     71 
     72 MACOS="-nostdinc -isystem $ZIGLIB/include -isystem $ZIGLIB/libc/include/any-macos-any"
     73 
     74 transpile linux   amd64
     75 transpile linux   arm64 --cpp=aarch64-linux-gnu-gcc
     76 transpile darwin  amd64 $MACOS
     77 transpile darwin  arm64 $MACOS
     78 transpile windows amd64 --cpp=x86_64-w64-mingw32-gcc
     79 transpile windows arm64 --cpp=x86_64-w64-mingw32-gcc
     80 
     81 ls -la "$OUT"