Joseph Ferano
a64bee6d96
Three defects, all from lifting every def initialiser, none of which the suite caught: A def typed fresh into a live session came up zero and stayed zero. The image flan_dev_global copies on the allocation is the only value a new global ever gets — the host's .init-globals never calls its initialiser — and both backends chose that image with Tast.const_init, which a def's lifted Call fails by construction. Emit.initial_image reads the constant back out of the lifted body; the x86 twin had the same bug. Changing a global between def and defonce was silently ineffective: the guard lives in the startup function compiled into the host, which a reload cannot republish. Session.compatible refuses both directions and says to restart; editing the value stays allowed. And global/<n> no longer leaks into the signature refusal when a def is retyped — the global loop names the same fact in words a reader can act on. flan check prints def, defonce or defconst off grerun; (defvar) with no arguments names the shapes rather than offering (defonce ); the docs, plan.org, runtime comments and valgrind.supp are swept; BUILT.md states the release-build cost and the uninit caveat.
39 lines
1.6 KiB
Plaintext
39 lines
1.6 KiB
Plaintext
;;;; (bytes s) copies, (bytes-view s) aliases — the ruling from the
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;;;; INSERTIONSORT dogfooding session. The pin is the exact inverse of the
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;;;; old aliasing: a write through the copy leaves the original string
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;;;; printing unchanged, where the old (bytes s) either showed the write
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;;;; through or trapped, depending on where the string's storage was.
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(defonce frame Allocator)
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(defn main [] i32
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;; 1. The copy is writable and independent. Under the old reinterpret this
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;; second line printed ZNSERTIONSORT too (or the whole program died in
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;; .rodata) — the original staying itself is the whole of the change.
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(let [s "INSERTIONSORT"
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b (bytes s)]
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(set (at b 0) \Z)
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(println (string b)) ; ZNSERTIONSORT
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(println s)) ; INSERTIONSORT
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;; 2. A literal's copy is writable — the exact form that used to segfault
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;; at -O0 and silently do nothing at -O2.
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(let [b (bytes "hi")]
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(set (at b 0) \H)
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(println (string b))) ; Hi
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;; 3. The view still costs nothing and reads the string's own storage.
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(let [v (bytes-view "abc")]
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(println (len v)) ; 3
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(println (at v 2))) ; 99
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;; 4. (bytes s a) names the allocator, like (vec-new T a) and (clone v a):
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;; the copy's block comes from the arena and free-all reclaims it.
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(set frame (arena-new 4096))
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(let [b (bytes "arena" frame)]
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(set (at b 4) \A)
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(println (string b))) ; arenA
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(free-all frame)
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(arena-destroy frame)
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0)
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