Joseph Ferano
63d9b87b7a
The transfer channel was the only thing between 41 programs and the corpus. It is there now: a guard after every Flan call, a landing pad per restart-case, handler-bind and with-allocator, a transfer exit per function that runs its fdefers, and check_at and check_slice, which could not exist until the guard did. Measured by what the programs print and what they exit with, never by reading bytes. spike/x86/survey.sh builds every program in test/programs both ways and diffs stdout and the exit status; it did not exist, so it is here too, and it is the progress meter. before 41 MATCH 1 DIFFER 41 refused by name after 83 MATCH 0 DIFFER 0 refused by name The one DIFFER was bounds.flan, and it was the honest answer to "--x86 is silently a --no-bounds-checks build". It is not one any more: check_at and check_slice signal through the channel exactly as emit.ml's do, so a bounds violation signals, a restart-case catches it, and an unhandled one exits 134 on both backends. The transitional refusal that would have said so retired before it was written. check_no_transfer is not removed, it is narrowed to the one place the argument still holds: a global's initialiser runs from flan..init-globals, before main and before anything can handle anything, so a transfer out of it has nowhere to go. Four bugs, and three of them are the shape item 16 predicted -- code that reads correctly and answers wrong, found by output and not by objdump: - The body fell through into the transfer exit, so every fdefer ran twice on a normal return. emit.ml cannot have this bug: its ret terminates the block. - A Vec crossed to the runtime as the address of a *copy*, so pushes grew the copy and an in-bounds (at v 1) signalled against a length of zero. - ucomis sets CF, ZF and PF together for a NaN, so sete answered true for (= x x) and the prelude's NaN test never fired: (/ 0.0 0.0) formatted as -9223372036854775808. Flan's comparisons are LLVM's ordered ones, so < and <= swap and =, != take a setnp beside them. - A union read field 0 through the struct table and was refused by name rather than laid out as a tag and a payload. And one that could not have been found later: emit_globals_init stored a null *into* the channel slot rather than a cell address into it, which is a null pointer for every callee to write through. Harmless while nothing could transfer; a fault the first time a guard loaded through it.
