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Paul Hontz
d9669f6eef
The arm64 and Android guests are compiled for arm64_32-apple-watchos and
their Darwin assembly converted to ELF (tools/android_asm_convert.py). The
converter took a quoted .ascii/.asciz operand for a quoted symbol name and
dropped a leading "_" from it, as it does from symbols; and its quoted-name
pattern ended at an escaped quote (\"), so the "_" of a word after one was
dropped too. Clang writes byte tables as .ascii strings, so a table holding
95 ("_") lost that byte and everything after it moved down by one.
In Opus that table was CELT's pulse cache (modes.c, cache_bits50): the bits
a band may have are read off it, and shifted by a byte it lets a band have
more pulses than the PVQ tables hold. Decoding a frame from another player
then read past CELT_PVQ_U_ROW in decode_pulses (n 32, k 240) and crashed: a
client on the Steam Frame, in a CTF game on the internet. The guest's own
encoder could crash likewise in encode_pulses. The same build of Opus,
driven with the game's settings and with clean, corrupt, truncated and
random packets and voice_audio_play's loss handling, crashed within a few
thousand frames (and identically at -O0); with the fix it ran 4.8 million
decodes clean, and its encoded bytes and decoded samples are identical to a
native 64-bit build's.
The same loss hit other strings and tables of the guest: musl's iswalpha,
iswpunct and towctrans tables and iconv's charmaps; tomlc17's "_0123..."
digit sets (TOML numbers with "_"); the attract mode's "_de"/"_fr" names,
"_lan_", "_lit" and "_%s"; the progress bar's compressed monk tone and the
DirectSound effects image; and assertion and error texts. All are now
assembled as compiled.
String directives now go through unchanged, and quoted names honour
escapes. tools/test_android_asm_convert.py checks both, and a table of
every byte value through clang, the conversion and the assembler.