Porting/Chromium/BE
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Changes required to Chromium to work on big endian
- Skia
- - Chromium assumes that the pixel format, when viewed as a 32-bit word, is either ARGB or ABGR. However, third_party/skia/include/core/SkImageInfo.h contains a check that the pixel format, when viewed as four 8-bit bytes, is either BGRA or RGBA. Hence either this check needs to be relaxed (Maybe it is bogus in the first place? The comments talk about "native ARGB 32-bit", yet the test goes out of its way to test the ordering as bytes and not as 32-bit words), or Chromium needs to learn about a different pixel format.
- Datapack
- ui/base/resource/data_pack.cc
- - Need to byteswap metadata on input (resource file format is specified to use LE)
- chrome/browser/themes/browser_theme_pack.cc
- - "datapack assumes little endian"
- Net
- net/cert/crl_set.cc
- - "assumes little endian"
- components/safe_browsing/db/v4_rice.cc
- - #error The code below assumes little-endianness.
- Media
- media/ffmpeg/ffmpeg_common.cc and media/formats/mp4/box_definitions.cc
- - #error The code below assumes little-endianness.
- media/renderers/paint_canvas_video_renderer.cc
- - Depending on choice of Skia pixel format, a new LIBYUV mapping set may be needed (see also third_party/libyuv below).
- I18N
- base/i18n/icu_util.cc
- - Needs to use "icudtb.dat" instead of "icudtl.dat" on BE
- Sandbox
- sandbox/linux/system_headers/linux_seccomp.h
- - The definition of the big endian variant is incorrect (contains a bogus "__AUDIO_ARCH_BE"). Also, it would be better to define two different macros AUDIT_ARCH_PPC64 and AUDIT_ARCH_PPC64LE (because that is how it actually looks in <linux/audit.h>), and choose the correct one in sandbox/linux/bpf_dsl/seccomp_macros.h instead.
- third_party/skia
- include/private/GrTypesPriv.h
- - #error "Skia gpu currently assumes little endian"
- src/opts/Sk4px_none.h
- - Sk4px::alphas, Sk4px::zeroAlphas, Sk4px::zeroColors: "This method assumes little-endian."
- src/opts/SkXfermode_opts.h
- - a_rgb assumes specific component order
- src/utils/SkJSON.cpp and src/utils/SkJSON.h
- - Tagged value implementation needs to be adapted for BE
- third_party/boringssl/src
- crypto/fipsmodul/bn/bytes.c
- - Bignum I/O functions need adaption for BE
- third_party/blink
- renderer/platform/graphics/gpu/webgl_image_conversion.cc
- - Does contain BE support, but a variable rename refactoring is missing from the BE code
- renderer/platform/graphics/logging_canvas.cc
- - Does contain BE support, but a variable rename refactoring is missing from the BE code
- renderer/platform/image-decoders/jpeg/jpeg_image_decoder.cc
- - #error Blink assumes a little-endian target.
- renderer/platform/image-decoders/webp/webp_image_decoder.cc
- - #error Blink assumes a little-endian target.
- renderer/platform/heap/asm/SaveRegisters_ppc64.S
- - Needs to handle ELF ABI v1
- third_party/perfetto
- src/ipc/buffered_frame_deserializer.cc, src/ipc/buffered_frame_deserializer_unittest.cc
- - Uses "AssumeLittleEndian" template
- src/protozero/message.cc
- - float and double handling need adjusting for BE (accoring to comment)
- src/protozero/proto_decoder.cc
- - Byteswap implementations missing
- third_party/ffmpeg
- chromium/scripts/build_ffmpeg.py
- - Needs to recognize 'ppc64' as well as 'ppc64le'
- third_party/webrtc
- common_audio/wav_file.cc
- - WavReader::ReadSamples and WavWriter::WriteSamples need to byteswap the samples
- common_audio/wav_header.cc
- - Conversion functions missing
- third_party/modp_b64
- BUILD.gn
- - modp_b64 actually supports BE, but in converting to their own build system Google managed to lose the check to define WORDS_BIGENDIAN
- modp_b64.cc
- - The prototype of modp_b64_decode needs to be updated to use size_t instead of int for the lengths, as it has been done for the LE variant
- third_party/libvpx
- - The build system should move VSX-specific sources into a separate source set, and set the cflags "-maltivec -mvsx" for it. In the original build system the cflags were set based on a glob of the source filename, but in Googles build system it has to be done manually.
- third_party/libyuv
- - Depending on choice of Skia pixel format, additional conversion function variants may be needed