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w6c_ww/cgen: size [N]enum element from tinfo not slotsize (fix #8)

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wwstage sized a named-enum array element (`[N]tk`, tk = enum i32) as a
raw 8-byte slot instead of its i32 backing (4), via two sibling code
paths that both derived the element width structurally and missed the
enum's underlying size:

  - elemsizeofc (cgenutil.ww) was the odd-one-out among the elem*c
    helpers: elemissignedc/elemisfloatc already read the checker-stamped
    tinfo (t.type_.sub), but elemsizeofc went elemsizeof->primsize->
    slotsize, and primsize("tk")=0 fell through to 8. This drove the
    cgindex READ: `a[i]` strode by 8 (MOVQ) where cstage strode by 4
    (MOVSXD), reading the wrong/out-of-bounds element for i>=1.

  - the array-literal init STORE (cgenstmt.ww) computed its own esz the
    same way (primsize=0 -> stayed at the 8 sentinel, enum is not an
    aggregate), so a local `[N]enum` literal stored at stride 8 into a
    stride-4 frame slot, overrunning it and smashing the saved BP /
    return addr -> wwstage-built binary SEGFAULTED.

Both align UP to cstage, which reads the stamped element size uniformly
(N_INDEX idx_eff(bt)->sub->size; N_LET array-init lu->sub->size,
cgen.c:6387). The read fix brings all four elem*c helpers onto the same
tinfo SSoT; the store fix takes the stamped element size for a narrow
scalar. Closing both close-by-construction at the size source.

No in-tree [N]enum / aliased-narrow element existed before kwtab, so
this was byte-id-gate-blind until now. test/wcc/682_arr_enum_elem.c
pins it table-driven: global+local reads, local init-store, signed
sign-extend, and a frame-smash row, each run through both stages with
exit-code and cstage==wwstage asm-byte-id checks.
This commit is contained in:
Hojun-Cho
2026-06-03 14:48:12 +09:00
parent 6b67655eca
commit d39691a3d7
6 changed files with 413 additions and 0 deletions
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7
Makefile
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@@ -239,6 +239,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
$(BIN)/test_int_cast_signed $(BIN)/test_dot_chain \
$(BIN)/test_amp_dot $(BIN)/test_arr_elem_field \
$(BIN)/test_arr_elem_field_write \
$(BIN)/test_arr_enum_elem \
$(BIN)/test_dot_str_chained_arg \
$(BIN)/test_dot_slice_arg \
$(BIN)/test_dot_tagged_source \
@@ -546,6 +547,12 @@ $(BIN)/test_arr_elem_field_write: test/wcc/681_arr_elem_field_write.c $(BIN)/ww
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_arr_enum_elem: test/wcc/682_arr_enum_elem.c $(BIN)/ww \
$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
$(LIB)/libwwrt.a | $(BIN)
$(CC) $(CFLAGS) -o $@ $<
$(BIN)/test_dot_str_chained_arg: test/wcc/692_dot_str_chained_arg.c $(BIN)/ww \
$(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \