Hojun-Cho/ww
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

wcc_ww/cgen: #101 narrow-alias fill-stride via aliasprimsize SSoT

Browse Source 
A struct-literal array fill sized a narrow-alias element off a bare
primsize(name): `type my32 = u32` gave primsize("my32")=0, so the
element width defaulted to 8 and a [3]my32 strode MOVQ -24/-16/-8 —
field n collided with arr[2] (kw1_101 run exit 1). cstage chases
my32->u32->4 (MOVL stride-4) at the twin sites and is runtime-correct;
this is a ww-only align-up, cs untouched.

Fix: a new aliasprimsize(c, nm) SSoT helper — primsize(nm), else an
aliaslookup-chase N_TNAME loop then primsize — and route the SIZE-use
primsize() family through it. The 7 c-bearing bare-no-chase size-use
sites are routed: cgen:993 (letemitsize), cgenstmt:1896 (cgarrlitfillbp),
cgenutil:1579 (elemsizeofc fallback)/1657+1665 (nodeprimwidth)/4791
(cgstructlitfill = the kw1_101 site), cgenexpr:6902 (cgcall vararg esz).
This is the rule-13 close-by-construction shape (one accessor for
"resolved primitive size"), not a per-site patch.

kw1_101 is the SOLE asm mover (byte-id NO->YES, run 1->0, MOVL
stride-4); every other routed site is latent/byte-neutral. Bootstrap:
all 5 combined units stay w6c==w6c_ww byte-identical. sizelint 0,
peellint 0, test-unit 296/296.

Scope fence (rob route-7-decline-6 ruling): three DESIGNED-exemption
sites carry inline primsize-ok annotations — elemsizeof :1475/:1499 and
paramfieldsize :3541 are structural (no-`c`, non-chasing) BY DESIGN;
their alias-chasing twin elemsizeofc is the routed :1579 leg. These are
the #109 peellint-whitelist seeds. Three further declines are already
correct chasing paths, not bare-no-chase bug shapes (typenodeprimresolved
:2026 / exprprimresolved :2063 are the chase machinery itself; cgassign
:7631 already chases via typenodeprimresolved, #11). The ~17 GUARD sites
(is-primitive dispatch) + the peellint finale are the committed #109
follow-on. Threading `c` into the structural sizers is dormant #110.

#101
This commit is contained in:
Hojun-Cho
2026-06-06 10:04:37 +09:00
parent c9cfa52624
commit 45f5415209
7 changed files with 159 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
selfhost/cmd/wcc/cgenstmt.ww
View File

@@ -1893,7 +1893,7 @@ fn cgarrlitfillbp(c: *cgen, arrtn: *node, rhs: *node, off: i32) void = {
esz = primtypesize("str"): i32;
isstrel = true;
} else {
let ps: i32 = primsize(elemn.str);
let ps: i32 = aliasprimsize(c, elemn.str);
if (ps > 0) { esz = ps; };
};
};
@@ -3538,6 +3538,11 @@ fn paramfieldsize(t: *node) i32 = {
if (k == nkind.N_TNAME) {
let nm: str = t.str;
if (streq(nm, "str")) { return primtypesize("str"): i32; };
// primsize-ok (#101/#109): paramfieldsize is a STRUCTURAL
// (no-`c`, no-chase) sizer by design — it takes a *node, not a
// *cgen, so it cannot run aliasprimsize's aliaslookup chase
// (threading c is the dormant #110). A bare primsize is correct
// here, not the #101 narrow-alias bug shape.
let ps: i32 = primsize(nm);
if (ps > 0) { return ps; };
};