Fix disassembler silent truncation - #14136
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Capstone's `disasm_all` stops at the first instruction it can't decode and returns success with whatever it managed to decode. We never compared that against the block length, so that instruction and everything after it vanished from the listing. For `precise-output` filetests the truncated output gets blessed, and the test then passes without asserting anything about those bytes. This is reachable today: the bundled capstone can't decode AVX-VNNI, so a function containing `vpdpbusd` was silently dropping five instructions. It is also a precursor to the APX work, whose EVEX map 4 encodings hit the same path; those filetests were being blessed as truncated output and so verified nothing about the instructions they were added to cover. Print the leftover bytes as `.byte`, keeping the reloc and trap annotations. s390x expectations already look like this. Resyncing after the bad instruction isn't possible on x86 without knowing its length, and guessing yields plausible but wrong instructions. The updated expectations only gain lines; nothing already printed changed. Those blocks end in constant pool data that capstone was already rendering as nonsense. prtest:full
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Capstone's
disasm_allstops at the first instruction it can't decode andreturns success with whatever it managed to decode. We never compared that
against the block length, so that instruction and everything after it
vanished from the listing. For
precise-outputfiletests the truncatedoutput gets blessed, and the test then passes without asserting anything
about those bytes.
This is reachable today: the bundled capstone can't decode AVX-VNNI, so a
function containing
vpdpbusdwas silently dropping five instructions.It is also a precursor to the APX work, whose EVEX map 4 encodings hit the
same path; those filetests were being blessed as truncated output and so
verified nothing about the instructions they were added to cover.
Print the leftover bytes as
.byte, keeping the reloc and trapannotations. s390x expectations already look like this. Resyncing after
the bad instruction isn't possible on x86 without knowing its length, and
guessing yields plausible but wrong instructions.
The updated expectations only gain lines; nothing already printed changed.
Those blocks end in constant pool data that capstone was already rendering
as nonsense.