bigmerge
c6ba0677f0
cycles/ one file per Ishikawa -> scientific method -> Six Sigma loop, named
for the DEFECT not the fix, carrying the commit record as written at
the time
findings/ what the cycles produced, cross-cut: live bugs, architecture answers,
and defects in my own measurement
The organising finding is that predictions which came back FALSE produced every
significant result. Eleven of sixty-one failed, and those eleven found: that the
arity table was not drifted but 40% incomplete; that the AST traversal is
irreducible and only rules and judgments move; that guards could refuse through
the seam after all; and that routing el_bin_lookup through the gate did NOT fix
the SIGSEGV, because the fallback strlen was the hazard -- a wrong fix I would
otherwise have shipped as verified.
One cycle was run without committing predictions first and had to be discarded
as rigged. It is kept, in full, as 18-async-half-expressible.md.
7.2 KiB
7.2 KiB
the crossing resolves at emission
One Ishikawa → scientific method → Six Sigma loop. The record below is the
commit message as written at the time, before the outcome was known to anyone
reading this file.
Record — 35b07ba
EXPERIMENT: resolve the crossing at execution, not at emission
HYPOTHESIS (Will's): a compiler whose one compiled mechanism is extending the
LANGUAGE — not the compiler — can compose without recompilation.
ISHIKAWA — why does a construct require a recompile today?
method codegen inlines the target call into the body
machine the binary has no table to consult
material the declaration lives in source, read at compile time
measurement nothing observes what applied at runtime
root cause the crossing is resolved at EMISSION, not at EXECUTION
CHANGE: codegen emits one unconditional indirection per fn. Which constructs
apply is read from a table that can be written AFTER the binary exists;
targets resolve through dlsym against the running image.
PREDICTIONS AND RESULTS
P1 a construct declared after the build applies TRUE
P2 an unlinked target is skipped, not fatal TRUE
P3 emitting on every fn is measurably slower FALSE — 0.37s -> 0.36s
with 267 indirections and
no bindings. Free unused.
P4 the compiler still self-hosts TRUE (see note)
DEMONSTRATED: an El program with NO decorator in its source, already compiled
and linked, picked up a construct declared afterwards:
$ /tmp/seamrun -> 7
$ echo 'work audited entry audit_entry' > constructs.txt
$ EL_CONSTRUCTS=constructs.txt /tmp/seamrun
AUDIT: work applied by audited
7
P4 note: my first fixpoint test was wrong, not the code. I compared gen1 to
gen2, which must differ whenever codegen's output changes. gen2 == gen3, 267
seam sites, stable.
MEASURED COST, and the root cause was not where I looked
0 bindings 0.36s vs 0.37s baseline free
2 bindings, dlsym per call 2.45s 6.6x
2 bindings, resolved once 0.69s 3.5x recovered
The table scan was never the cost. dlsym walks the dynamic symbol table on
every call. Resolve once and cache — which is the smallest form of what
salience does for memory: what is hot stays resolved. The 0.69s residual is
audit_entry's own printf on two of the compiler's hottest functions, not seam
overhead.
CONSEQUENCE: the five compile-time declaration kinds on iteration-1 are a
compile-time specialisation of something that resolves at runtime. They are not
wrong, but they are not the mechanism — the mechanism is one indirection, and a
kind is data.
Record — 886626a
seam refusal + control tests: a runtime binding can short-circuit
Prediction 3 was FALSE. I expected refusal to be impossible through the seam
because the entry indirection discarded its return. One line:
{ el_val_t __s = el_seam_run(EL_STR(f), 0, 0); if (__s) return __s; }
work() returns 7; bound to a refusing construct AFTER the build it returns 42.
So three of the five compile-time kinds are runtime-bindable: entry injection,
exit injection, and refusal. wraps_body needs invocation control and
prohibits_outside is compile-time by nature.
104/104 native compiler tests pass.
Record — 28d19da
strip the compile-time machinery the seam replaces
PREDICTION: codegen.el drops below 4661, its size before any of these passes.
RESULT: FALSE. 5157 -> 5096. Still +435 over baseline.
injects_at_entry collapsed into the seam removed
guards_at_entry collapsed into the seam removed
injects_at_exit needs the body-helper wrapper STRUCTURAL
wraps_body needs the closure + wrapper structural
prohibits_outside a #error cannot be emitted at runtime
The wrapper is not a consequence of compile-time resolution. Early returns must
be routed through something no matter when the target is resolved, so exit
injection was never going to collapse. I predicted it would because I had
conflated "resolved late" with "emitted less".
What did collapse is entry injection and refusal -- 61 lines of compiler
replaced by one refusable indirection, with the capability now bindable after
the binary exists.
8 tests fail, and they are exactly the 8 controls for compile-time entry
injection and guards. No unrelated breakage: the controls reported precisely
what moved. They assert emission of something that now happens at runtime, so
they need rewriting as integration tests -- which the framework does not
currently support, because runtime binding needs a built binary and an
environment, not compile_capture.
Verified after the strip: fixpoint gen2==gen3, observation and refusal both
work through the seam with the compiler knowing nothing about either.
Record — 8bbb750
control the claim that cannot be unit tested
The seam's whole claim is that a construct declared AFTER a binary exists
applies to that already-built program. compile_capture only sees emitted text,
so it structurally cannot check this: it needs a built binary, a linked target,
and an environment. Verified by hand until now, which is the standing problem
this session has been about.
tests/integration/seam_binding.sh builds a probe from El source containing no
construct at all, links a target that El never references, and asserts:
ok unbound program is unaffected
ok a construct declared AFTER the build applies
ok a construct declared after the build can REFUSE
ok an unlinked target is skipped, not fatal
ok a binding for a different fn does not fire
ok two constructs compose on one crossing
6 assertions, 6 passed, 0 failed
The eight controls that failed after the strip were replaced, not repaired.
They asserted compile-time emission of capability that moved to runtime;
contorting them would have kept an assertion whose subject no longer exists.
Three took their place, asserting the emitted shape, and the behaviour they
used to cover is now the integration harness's job -- which is the honest
division, since the shape and the behaviour are no longer the same fact.
99/99 native compiler tests pass. Fixpoint holds.
Record — 24f7fb5
land the runtime seam: resolve the crossing at execution
Five compile-time passes added 491 lines to the thing that was supposed to stop
growing. The seam is ~55 lines of C and one line of emission, and it does at
runtime what three of those five kinds did at compile time -- for programs that
are already built.
a construct declared AFTER the binary exists applies to it
free when unused: 0.36s vs 0.37s baseline across 267 indirections
dlsym was the cost, not the table scan; resolve-once recovered 3.5x
refusal works, composition works, unlinked targets are skipped not fatal
injects_at_exit and wraps_body do NOT collapse: early returns must route
through the body-helper wrapper regardless of when the target is resolved. The
wrapper is structural, which I had wrong. prohibits_outside cannot move at all
-- a #error has no runtime.
Controls: 99/99 native compiler tests, plus tests/integration/seam_binding.sh
(6/6) for the claim compile_capture structurally cannot see.