From 8ae77db92cb2b7ce701cc56946e23098447533d1 Mon Sep 17 00:00:00 2001 From: Joseph Ferano Date: Sun, 13 Sep 2026 23:12:43 +0700 Subject: [PATCH] A redefined function that takes and returns a struct, on both backends --- test/programs/reload-agg-v2.flan | 69 +++++++++++++++++++++ test/programs/reload-agg.flan | 101 +++++++++++++++++++++++++++++++ test/test_reload.ml | 96 +++++++++++++++++++++++++++++ 3 files changed, 266 insertions(+) create mode 100644 test/programs/reload-agg-v2.flan create mode 100644 test/programs/reload-agg.flan diff --git a/test/programs/reload-agg-v2.flan b/test/programs/reload-agg-v2.flan new file mode 100644 index 0000000..34702bd --- /dev/null +++ b/test/programs/reload-agg-v2.flan @@ -0,0 +1,69 @@ +;;;; The aggregate case across the reload boundary, v2. +;;;; +;;;; The same four signatures with different arithmetic, so that the host's +;;;; un-rebuilt `outer' printing a different number can only mean its call +;;;; sites followed four redefined bodies that take and return structs. +;;;; +;;;; The `defstruct' blocks are byte-identical to v1's and must stay that way. +;;;; Layout is computed per module, so a field reordered here would make the +;;;; host and the module disagree about offsets — a real bug, but one wearing +;;;; this test's clothes, and it would be indistinguishable in the transcript +;;;; from the convention mismatch the fixture exists to detect. +;;;; +;;;; The four `weigh' functions are changed and the change must be dead text: a +;;;; module declares a sibling rather than defining it, so each call has to +;;;; land on the host's copy. With the bodies identical nothing at run time +;;;; would notice a module that grew its own; multiplied by ten, it is the +;;;; difference between 1611 and 12411 in the first term alone. +;;;; +;;;; Nothing here introduces a name the host was not built with. X86.redefinition +;;;; refuses those by name — that is the registry path, and it is item 1 of +;;;; HANDOFF-x86-redef.md's "what remains" rather than anything to do with +;;;; aggregates. + +(defstruct Pair [a i64 b i64]) +(defstruct Quad [a i64 b i64 c i64 d i64]) +(defstruct Duo [x f64 y f64]) +(defstruct Mix [n i64 z f64]) + +(defvar counter i64) + +(defn weigh-pair [p Pair] i64 (+ (.a p) (* 30 (.b p)))) + +(defn weigh-quad [q Quad] i64 + (+ (+ (.a q) (* 30 (.b q))) (+ (* 50 (.c q)) (* 70 (.d q))))) + +(defn weigh-duo [d Duo] i64 (+ (i64 (.x d)) (* 30 (i64 (.y d))))) + +(defn weigh-mix [m Mix] i64 (+ (.n m) (* 30 (i64 (.z m))))) + +(defn step-pair [p Pair] Pair + (println "a2") + (set counter (+ counter 10)) + (Pair {.a (+ (.a p) 10) .b (+ (.b p) (* 2 (weigh-pair p)))})) + +(defn step-quad [q Quad] Quad + (Quad {.a (+ (.a q) 10) .b (+ (.b q) 20) .c (+ (.c q) 30) + .d (+ (.d q) (* 2 (weigh-quad q)))})) + +(defn step-duo [d Duo] Duo + (Duo {.x (+ (.x d) 10.0) .y (+ (.y d) (f64 (* 2 (weigh-duo d))))})) + +(defn step-mix [m Mix] Mix + (Mix {.n (+ (.n m) 10) .z (+ (.z m) (f64 (* 2 (weigh-mix m))))})) + +(defn sum-pair [p Pair] i64 (+ (.a p) (* 100 (.b p)))) + +(defn sum-quad [q Quad] i64 + (+ (+ (.a q) (* 100 (.b q))) (+ (* 10000 (.c q)) (* 1000000 (.d q))))) + +(defn sum-duo [d Duo] i64 (+ (i64 (.x d)) (* 100 (i64 (.y d))))) + +(defn sum-mix [m Mix] i64 (+ (.n m) (* 100 (i64 (.z m))))) + +(defn outer [] i64 + (let [p (step-pair (Pair {.a 1 .b 2})) + q (step-quad (Quad {.a 1 .b 2 .c 3 .d 4})) + d (step-duo (Duo {.x 1.0 .y 2.0})) + m (step-mix (Mix {.n 1 .z 2.0}))] + (+ (+ (sum-pair p) (sum-quad q)) (+ (sum-duo d) (sum-mix m))))) diff --git a/test/programs/reload-agg.flan b/test/programs/reload-agg.flan new file mode 100644 index 0000000..840991f --- /dev/null +++ b/test/programs/reload-agg.flan @@ -0,0 +1,101 @@ +;;;; The aggregate case across the reload boundary, v1 (HANDOFF-x86-redef.md, +;;;; item 4). +;;;; +;;;; `reload.flan' proves that a redefined body is reached; every signature in +;;;; it is scalar. That is the half of the reload primitive the two backends +;;;; cannot disagree about. `lib/x86.ml' licenses its own calling convention on +;;;; the grounds that a dev build is compiled entirely by it and a release +;;;; build entirely by LLVM, and the conventions agree on every scalar and +;;;; disagree on every aggregate — here each goes by pointer with a hidden +;;;; sret, while LLVM classifies per eightbyte. So a redefined function taking +;;;; or returning a struct is the case that would expose a mismatch, and it is +;;;; the case nothing measured. This fixture is that case. +;;;; +;;;; No `main': the host is test/reload_host.c, unchanged, which links this and +;;;; then dlopens rebuilt copies. Everything aggregate happens *inside* Flan, +;;;; between the host's compiled-once call site and the redefined body. The C +;;;; boundary stays scalar on purpose — that is where the two conventions are +;;;; required to agree, and it is not what is under test. +;;;; +;;;; Four struct shapes, because SysV treats them four different ways and +;;;; x86.ml treats all four the same: +;;;; +;;;; Pair two eightbytes, both INTEGER — SysV passes it in rdi:rsi and +;;;; returns it in rax:rdx. Diverges from x86.ml in both directions. +;;;; Quad thirty-two bytes, so MEMORY — SysV copies the argument onto the +;;;; stack, where x86.ml passes a pointer. The *return* is a hidden +;;;; pointer in the first integer register for SysV too, so that half +;;;; of the matrix may well coincide; it is covered because assuming +;;;; which half coincides is exactly the kind of argument this fixture +;;;; exists to replace with a measurement. +;;;; Duo two SSE eightbytes — xmm0:xmm1. +;;;; Mix one INTEGER and one SSE — rax and xmm0, a third pattern again. +;;;; +;;;; Every field is weighted by position in the answer — a + 100b + 10000c — +;;;; rather than summed. A symmetric sum would print the right number under a +;;;; convention mismatch that merely permuted the fields, which is the way a +;;;; test like this passes while proving nothing. + +(defstruct Pair [a i64 b i64]) +(defstruct Quad [a i64 b i64 c i64 d i64]) +(defstruct Duo [x f64 y f64]) +(defstruct Mix [n i64 z f64]) + +;;; The state that has to survive a reload, written by a loaded module rather +;;; than by the host: a redefinition declares it external, so the store lands +;;; on the host's copy and not on a private one. +(defvar counter i64) + +;;; The other direction. These are never redefined, so a module reaches each +;;; one through its cell and hands it an aggregate — module to host, where the +;;; four `step' functions below are host to module. Each is also a tripwire: +;;; v2 changes all four, and since a module declares a sibling rather than +;;; defining it, that changed text must be dead. A module that grew its own +;;; copy prints a visibly different number. +(defn weigh-pair [p Pair] i64 (+ (.a p) (* 3 (.b p)))) + +(defn weigh-quad [q Quad] i64 + (+ (+ (.a q) (* 3 (.b q))) (+ (* 5 (.c q)) (* 7 (.d q))))) + +(defn weigh-duo [d Duo] i64 (+ (i64 (.x d)) (* 3 (i64 (.y d))))) + +(defn weigh-mix [m Mix] i64 (+ (.n m) (* 3 (i64 (.z m))))) + +;;; The four redefined bodies. Each takes an aggregate and returns one, so a +;;; single call crosses the boundary in both directions at once. +(defn step-pair [p Pair] Pair + (println "a1") + (set counter (+ counter 1)) + (Pair {.a (+ (.a p) 1) .b (+ (.b p) (weigh-pair p))})) + +(defn step-quad [q Quad] Quad + (Quad {.a (+ (.a q) 1) .b (+ (.b q) 2) .c (+ (.c q) 3) + .d (+ (.d q) (weigh-quad q))})) + +(defn step-duo [d Duo] Duo + (Duo {.x (+ (.x d) 1.0) .y (+ (.y d) (f64 (weigh-duo d)))})) + +(defn step-mix [m Mix] Mix + (Mix {.n (+ (.n m) 1) .z (+ (.z m) (f64 (weigh-mix m)))})) + +;;; The reducers the host itself calls, so that what crosses back into C is an +;;; integer and the transcript is exact. +(defn sum-pair [p Pair] i64 (+ (.a p) (* 100 (.b p)))) + +(defn sum-quad [q Quad] i64 + (+ (+ (.a q) (* 100 (.b q))) (+ (* 10000 (.c q)) (* 1000000 (.d q))))) + +(defn sum-duo [d Duo] i64 (+ (i64 (.x d)) (* 100 (i64 (.y d))))) + +(defn sum-mix [m Mix] i64 (+ (.n m) (* 100 (i64 (.z m))))) + +;;; The call site that has to follow a reload: compiled once, into the host, +;;; and never rebuilt. If a redefined `step-pair' runs when the host calls +;;; this, the cell is doing its job — and doing it for a signature the two +;;; conventions disagree about. +(defn outer [] i64 + (let [p (step-pair (Pair {.a 1 .b 2})) + q (step-quad (Quad {.a 1 .b 2 .c 3 .d 4})) + d (step-duo (Duo {.x 1.0 .y 2.0})) + m (step-mix (Mix {.n 1 .z 2.0}))] + (+ (+ (sum-pair p) (sum-quad q)) (+ (sum-duo d) (sum-mix m))))) diff --git a/test/test_reload.ml b/test/test_reload.ml index 626f0a3..b5ed8a3 100644 --- a/test/test_reload.ml +++ b/test/test_reload.ml @@ -252,6 +252,102 @@ let () = | _ -> fail "x86 redefinition accepted a name the host does not have" | exception X86.Unsupported _ -> ()); + (* The aggregate case, which is the whole reason X86.redefinition exists + rather than an --x86 host dlopening what Emit.redefinition made. + + Everything above this point is scalar, and scalars are the half of the + calling convention the two backends cannot disagree about. They disagree + on every aggregate: x86.ml passes each one by pointer and returns it + through a hidden sret, LLVM classifies per eightbyte. So a redefined + function taking or returning a struct is the case that would expose a + mismatch, and until now the claim that an --x86 host plus --x86 modules + is same-convention-by-construction was an argument rather than a + measurement. + + programs/reload-agg.flan crosses the boundary in four shapes at once — + two integer eightbytes, thirty-two bytes of MEMORY, two SSE eightbytes, + and one of each — because SysV treats those four differently and this + backend treats them identically, so a single shape would measure a + quarter of the disagreement and read like all of it. Each `step' takes + an aggregate and returns one, so a single call crosses in both + directions, and each calls a `weigh' the module does not define, which + hands an aggregate the other way. + + Both backends run the same fixture and are compared against the same + transcript. The LLVM row is not decoration: a wrong expected number + would otherwise be indistinguishable from a backend that is right, and + two independently-built agreements on one string are what rule that + out. *) + let a1 = checked "programs/reload-agg.flan" in + let a2 = checked "programs/reload-agg-v2.flan" in + let agg_known = + let names = + List.map (fun (f : Tast.fn) -> f.Tast.name) a1.Tast.fns + @ List.map (fun (g : Tast.global) -> g.Tast.gname) a1.Tast.globals + in + fun n -> List.exists (String.equal n) names + in + let agg_fns = [ "step-pair"; "step-quad"; "step-duo"; "step-mix" ] in + (* The arithmetic, derived rather than observed, because a number read off + a run is a record of what happened and not a statement of what should: + + v1 Pair {1,2} -> weigh 1+3*2 = 7, so {2, 2+7} and 2 + 100*9 = 902 + Quad {1,2,3,4} -> weigh (1+6)+(15+28) = 50, so {2,4,6,54} and + 2 + 400 + 60000 + 54000000 = 54060402 + Duo {1,2} -> weigh 7, so {2.0, 9.0} and 902 + Mix {1,2} -> weigh 7, so {2, 9.0} and 902 + total 54063108 + v2 Pair -> weigh is still the *host's* 7, so {11, 2+14} and 1611 + Quad -> weigh still 50, so {11,22,33,104} and + 11 + 2200 + 330000 + 104000000 = 104332211 + Duo -> {11.0, 16.0} and 1611 + Mix -> {11, 16.0} and 1611 + total 104337044 + + 1611 rather than 12411 in the first term is the tripwire: v2's text for + `weigh-pair' multiplies by thirty, and a module that grew its own copy + of a sibling rather than reaching the host's through a cell would say + so here. `counter' is stepped from inside the redefined body, by one in + v1 and by ten in v2, so 1 + 1 + 10 = 12 is the host's global being + written by three different bodies in turn. *) + let agg_want = + "a1\nhost 54063108\na1\nafter1 54063108\na2\nafter2 104337044\n\ + counter 12\n" + in + let agg_run label opts mkmod = + let h = tmp ("agg-host-" ^ label) in + ignore + (Build.executable ~opts ~csrcs:[ "reload_host.c" ] ~lflags:[ "-ldl" ] + a1 ~out:h); + let m1 = mkmod a1 ("agg-" ^ label ^ "-1.so") in + let m2 = mkmod a2 ("agg-" ^ label ^ "-2.so") in + let o = tmp ("agg-out-" ^ label) and e = tmp ("agg-err-" ^ label) in + let code = + Sys.command + (Printf.sprintf "%s %s %s > %s 2> %s" (Filename.quote h) + (Filename.quote m1) (Filename.quote m2) (Filename.quote o) + (Filename.quote e)) + in + let text = In_channel.with_open_bin o In_channel.input_all in + if code <> 0 || text <> agg_want then + fail "%s aggregate reload\n got: %S (exit %d)\n wanted: %S" + label text code agg_want; + List.iter (fun p -> try Sys.remove p with Sys_error _ -> ()) + [ h; m1; m2; o; e ] + in + agg_run "llvm" dev (fun q name -> + let o = tmp name in + let ir = Emit.redefinition ~dev:true ~known:agg_known q ~fns:agg_fns in + ignore (Build.shared ~opts:dev ~ir ~out:o ()); + o); + agg_run "x86" x86 (fun q name -> + let o = tmp name in + let asm = + X86.redefinition ~checks:true ~dev:true ~known:agg_known q ~fns:agg_fns + in + ignore (Build.shared_x86 ~opts:x86 ~asm ~out:o ()); + o); + (* The layout-drift guard, which needs a process of its own because what it does is abort one. [extra] does not exist in the host: v3 introduced it at run time, so flan_dev.c allocated its storage and recorded its size,