wcc/ww: match on a global value-struct tagged field reads g(SB) (#29)
A match whose scrutinee is a tagged field of a GLOBAL value-struct read the tag/payload from the BP region (saved-BP + return-addr) instead of g(SB) and returned garbage. Both stages were identical-wrong, so the byte-id gate could not see it -- a gate-blind regression introduced by M1 (#25): M1's in-place N_DOT match arm uses localfind(base), which returns the 0 not-found sentinel for a global base, so 0+field.offset landed in the frame. Gate the in-place arm on a confirmed-local base -- `localfind(base)==0 && let_islet/isletvar(base)`, verbatim from cstage's own global test at cgen.c:2000 (both stages, same spelling). A global base now falls through to the existing spill path, which cgexprs the scrutinee and resolves g(SB). M1's local-field in-place ($32) path is untouched. Regenerates the w6c and wwdump combined.ww. Table-driven 841 test (global int/reassign/str-payload + a local-field M1 regression row), runtime-discriminating: pre-fix returns garbage, post-fix 42 on both stages; rob's direct-global-field spill caveat confirmed at runtime.
This commit is contained in:
7
Makefile
7
Makefile
@@ -343,6 +343,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
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$(BIN)/test_tagged_widen_f64 \
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$(BIN)/test_match_spill_pointer_payload \
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$(BIN)/test_match_field_inplace \
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$(BIN)/test_match_global_field \
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$(BIN)/test_struct_byval_param \
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$(BIN)/test_struct_multi_return_scratch \
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$(BIN)/test_signed_data_emit \
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@@ -2125,6 +2126,12 @@ $(BIN)/test_match_field_inplace: test/wcc/831_match_field_inplace.c \
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$(LIB)/libwwrt.a | $(BIN)
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$(CC) $(CFLAGS) -o $@ $<
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$(BIN)/test_match_global_field: test/wcc/841_match_global_field.c \
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$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
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$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
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$(LIB)/libwwrt.a | $(BIN)
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$(CC) $(CFLAGS) -o $@ $<
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$(BIN)/test_struct_byval_param: test/wcc/717_struct_byval_param.c \
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$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
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$(BIN)/ww_ww $(BIN)/w6c_ww $(BIN)/w6a_ww $(BIN)/w6l_ww \
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@@ -10243,7 +10243,11 @@ cgexpr(Cg *c, Node *n, Local *locals)
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/* `match (p.field)` — point sl_off at the field's slot
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* inside the parent struct. The slot layout (tag at +0,
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* value words at +8/+16) is contiguous within the struct,
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* so no spill is needed. */
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* so no spill is needed. #29: gated below on a
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* CONFIRMED-LOCAL base — a global base (`match (g.field)`)
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* has localfind==0, so 0+field.offset would land in the
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* saved-BP/return-addr region; it falls through to the
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* spill `else`, which resolves g(SB). */
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Type *bt = s->lhs->type;
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Type *bu = type_chase_named(bt);
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Tfield *f = NULL;
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@@ -10254,8 +10258,8 @@ cgexpr(Cg *c, Node *n, Local *locals)
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}
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}
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}
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if (f) {
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int boff = localfind(locals, s->lhs->str);
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int boff = f ? localfind(locals, s->lhs->str) : 0;
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if (f && !(boff == 0 && let_islet(s->lhs->str))) {
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sl_off = boff + (int)f->offset;
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} else {
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/* fall back to spill — `match (h.e)` where
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@@ -26307,11 +26307,17 @@ fn cgmatch(c: *cgen, n: *node) void = {
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// type chases to TY_STRUCT and whose field resolves by name.
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// A *ptr-field base (`match (h.e)`, h:*struct) chases to
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// TY_PTR, the by-name scan misses, and it falls to the spill
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// arm below — exactly as cstage, no separate deref guard. A
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// global VALUE-struct base mis-resolves here in BOTH stages
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// (shared latent #29), matched identically — no ww-only
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// global guard. align-DOWN to cstage (rule 10): both stages
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// emit TEXT $32 on the local-field case.
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// arm below — exactly as cstage, no separate deref guard.
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// #29: the in-place arm is also gated on a CONFIRMED-LOCAL
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// base (bglobal below). A global VALUE-struct base
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// (`match (g.field)`) has localfind==0, so the M1 base.off
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// would land in the saved-BP/return-addr region — both
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// stages emitted `MOVQ (BP),AX` (gate-blind both-wrong). The
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// global-base predicate `localfind==0 && isletvar` (cstage
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// twin: let_islet, cgen.c:2000) routes it through to the
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// spill `else`, which resolves g(SB). align-DOWN to cstage
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// (rule 10): both stages emit TEXT $32 on the local-field
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// case and the same g(SB) spill on the global-field case.
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let mfld: *tfield = nil;
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if (scrut.kind == nkind.N_DOT && scrut.lhs != nil
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&& scrut.lhs.kind == nkind.N_IDENT
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@@ -26328,7 +26334,12 @@ fn cgmatch(c: *cgen, n: *node) void = {
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};
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};
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};
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let bglobal: bool = false;
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if (mfld != nil) {
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bglobal = (localfind(c, scrut.lhs.str) == 0)
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&& isletvar(c, scrut.lhs.str);
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};
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if (mfld != nil && !bglobal) {
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let foff: i32 = mfld.offset: i32;
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scrutoff = localfind(c, scrut.lhs.str) + foff;
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scrutt = matchscrutt(c, scrut);
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@@ -2961,11 +2961,17 @@ fn cgmatch(c: *cgen, n: *node) void = {
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// type chases to TY_STRUCT and whose field resolves by name.
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// A *ptr-field base (`match (h.e)`, h:*struct) chases to
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// TY_PTR, the by-name scan misses, and it falls to the spill
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// arm below — exactly as cstage, no separate deref guard. A
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// global VALUE-struct base mis-resolves here in BOTH stages
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// (shared latent #29), matched identically — no ww-only
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// global guard. align-DOWN to cstage (rule 10): both stages
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// emit TEXT $32 on the local-field case.
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// arm below — exactly as cstage, no separate deref guard.
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// #29: the in-place arm is also gated on a CONFIRMED-LOCAL
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// base (bglobal below). A global VALUE-struct base
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// (`match (g.field)`) has localfind==0, so the M1 base.off
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// would land in the saved-BP/return-addr region — both
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// stages emitted `MOVQ (BP),AX` (gate-blind both-wrong). The
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// global-base predicate `localfind==0 && isletvar` (cstage
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// twin: let_islet, cgen.c:2000) routes it through to the
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// spill `else`, which resolves g(SB). align-DOWN to cstage
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// (rule 10): both stages emit TEXT $32 on the local-field
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// case and the same g(SB) spill on the global-field case.
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let mfld: *tfield = nil;
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if (scrut.kind == nkind.N_DOT && scrut.lhs != nil
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&& scrut.lhs.kind == nkind.N_IDENT
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@@ -2982,7 +2988,12 @@ fn cgmatch(c: *cgen, n: *node) void = {
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};
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};
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};
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let bglobal: bool = false;
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if (mfld != nil) {
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bglobal = (localfind(c, scrut.lhs.str) == 0)
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&& isletvar(c, scrut.lhs.str);
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};
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if (mfld != nil && !bglobal) {
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let foff: i32 = mfld.offset: i32;
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scrutoff = localfind(c, scrut.lhs.str) + foff;
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scrutt = matchscrutt(c, scrut);
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@@ -26307,11 +26307,17 @@ fn cgmatch(c: *cgen, n: *node) void = {
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// type chases to TY_STRUCT and whose field resolves by name.
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// A *ptr-field base (`match (h.e)`, h:*struct) chases to
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// TY_PTR, the by-name scan misses, and it falls to the spill
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// arm below — exactly as cstage, no separate deref guard. A
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// global VALUE-struct base mis-resolves here in BOTH stages
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// (shared latent #29), matched identically — no ww-only
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// global guard. align-DOWN to cstage (rule 10): both stages
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// emit TEXT $32 on the local-field case.
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// arm below — exactly as cstage, no separate deref guard.
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// #29: the in-place arm is also gated on a CONFIRMED-LOCAL
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// base (bglobal below). A global VALUE-struct base
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// (`match (g.field)`) has localfind==0, so the M1 base.off
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// would land in the saved-BP/return-addr region — both
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// stages emitted `MOVQ (BP),AX` (gate-blind both-wrong). The
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// global-base predicate `localfind==0 && isletvar` (cstage
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// twin: let_islet, cgen.c:2000) routes it through to the
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// spill `else`, which resolves g(SB). align-DOWN to cstage
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// (rule 10): both stages emit TEXT $32 on the local-field
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// case and the same g(SB) spill on the global-field case.
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let mfld: *tfield = nil;
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if (scrut.kind == nkind.N_DOT && scrut.lhs != nil
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&& scrut.lhs.kind == nkind.N_IDENT
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@@ -26328,7 +26334,12 @@ fn cgmatch(c: *cgen, n: *node) void = {
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};
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};
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};
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let bglobal: bool = false;
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if (mfld != nil) {
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bglobal = (localfind(c, scrut.lhs.str) == 0)
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&& isletvar(c, scrut.lhs.str);
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};
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if (mfld != nil && !bglobal) {
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let foff: i32 = mfld.offset: i32;
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scrutoff = localfind(c, scrut.lhs.str) + foff;
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scrutt = matchscrutt(c, scrut);
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266
test/wcc/841_match_global_field.c
Normal file
266
test/wcc/841_match_global_field.c
Normal file
@@ -0,0 +1,266 @@
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/*
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* 841_match_global_field — match on a tagged-union struct-FIELD of a
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* GLOBAL (module-level) VALUE struct: `match (g.t)`, g a `let g: box`.
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* Task #29.
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*
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* GATE-BLIND both-wrong regression from M1 (#25). M1 added an in-place
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* N_DOT match arm that points the dispatch slot at base.off +
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* field.offset, computing base.off via localfind. For a LOCAL base that
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* is the field's true frame slot ($32 in-place, correct). For a GLOBAL
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* base localfind returns its 0/not-found sentinel, so 0 + field.offset
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* lands in the saved-BP / return-addr region (BP+0/BP+8): both stages
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* emit `MOVQ (BP),AX` and read garbage. Both stages were identical-wrong
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* (byte-id GREEN), so only the RUNTIME oracle catches it — pre-fix
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* match(g.t) returns 213 instead of 42.
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*
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* Fix (both stages, rule 10): gate the in-place arm on a confirmed-LOCAL
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* base. A base is GLOBAL iff localfind(base)==0 && let_islet(base)
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* (cstage) / isletvar(c, base) (wwstage) — the same idiom cstage uses at
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* cgen.c:2000 (also 4707/4730/5393). A global base falls THROUGH to the
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* existing spill `else`, which cgexprs the scrutinee and resolves g(SB)
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* correctly. M1's LOCAL in-place path is unchanged (row (d) pins it).
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*
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* Rows pin the RUNTIME exit code on BOTH driver stages (cstage +
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* wwstage) — the discriminator is the value, not byte-id, since both
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* stages were identical-wrong. A cstage-vs-wwstage asm byte-identity
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* check is kept per row so the symmetric (rule-10) property stays pinned
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* after the guard lands in both stages.
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* (a) global VALUE-struct int-variant field [spill, g(SB)]
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* (b) global field bool->int payload remap [1-word variant]
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* (c) global field str-payload (24B box) [3-word variant]
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* (d) local VALUE-struct field, in place [M1 regression guard]
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include <sys/wait.h>
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static int
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runwait(const char *cmd)
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{
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int rc = system(cmd);
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if (rc == -1) return -1;
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if (WIFEXITED(rc)) return WEXITSTATUS(rc);
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return -1;
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}
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struct row { const char *label; const char *src; int want; };
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static const struct row rows[] = {
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/* (a) GLOBAL value struct, field set to the int variant in main,
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* matched. Pre-fix the in-place arm read BP+0 (213); post-fix the
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* spill path resolves g(SB) and returns 42. */
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{ "global_field_int",
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"package main;\n"
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"type box = struct { t: (int | bool), n: int };\n"
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"let g: box = box { t = 0, n = 5 };\n"
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"fn main() i32 = {\n"
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" g.t = 42;\n"
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" match (g.t) {\n"
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" case let n: int => return n: i32;\n"
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" case bool => return 1;\n"
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" };\n"
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"};\n",
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42 },
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/* (b) GLOBAL field reassigned, then matched; the int arm also reads
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* the sibling field g.n to prove the surrounding global is
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* undisturbed. Returns 7 + 5 = 12. The static initializer uses the
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* ZERO payload (t = 0): a nonzero tagged-field payload in a static
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* struct initializer trips a SEPARATE, deferred static-init DATA
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* divergence (task #19/#30 — wwstage drops the payload word to 0,
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* cstage emits it) that is orthogonal to the #29 match-cgen path
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* exercised here; a zero payload is byte-identical across stages. */
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{ "global_field_reassign_remap",
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"package main;\n"
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"type box = struct { t: (int | bool), n: int };\n"
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"let g: box = box { t = 0, n = 5 };\n"
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"fn main() i32 = {\n"
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" g.t = 7;\n"
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" match (g.t) {\n"
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" case let n: int => return (n + g.n): i32;\n"
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" case bool => return 1;\n"
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" };\n"
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"};\n",
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12 },
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/* (c) GLOBAL field, 24B str-payload variant (tag@+0, .ptr@+8,
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* .len@+16). Returns len("hello") = 5. */
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{ "global_field_str_payload_24B",
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"package main;\n"
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"type box = struct { t: (str | int), n: int };\n"
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"let g: box = box { t = 0, n = 5 };\n"
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"fn main() i32 = {\n"
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" g.t = \"hello\";\n"
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" match (g.t) {\n"
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" case let s: str => return len(s): i32;\n"
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" case int => return 99;\n"
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" };\n"
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"};\n",
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5 },
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/* (d) regression guard: a LOCAL value-struct field still reads in
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* place (M1's $32 path stays). Returns 42. */
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{ "local_field_inplace_guard",
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"package main;\n"
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"type box = struct { t: (int | bool), n: int };\n"
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"fn main() i32 = {\n"
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" let b: box = box { t = 0, n = 5 };\n"
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" b.t = 42;\n"
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" match (b.t) {\n"
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" case let n: int => return n: i32;\n"
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" case bool => return 1;\n"
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" };\n"
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"};\n",
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42 },
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};
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static int
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run_driver(const char *driver, const struct row *r, int i)
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{
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char src[64], tmpdir[64], cmd[1024];
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snprintf(src, sizeof src, "/tmp/wcmgf_%d_%d.ww", getpid(), i);
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snprintf(tmpdir, sizeof tmpdir, "/tmp/wcmgf_%d_d_%d", getpid(), i);
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FILE *f = fopen(src, "wb");
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if (!f) return -1;
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fputs(r->src, f);
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fclose(f);
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mkdir(tmpdir, 0755);
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snprintf(cmd, sizeof cmd, "cd %s && %s build %s",
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tmpdir, driver, src);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "row[%s]: build via %s failed\n",
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r->label, driver);
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unlink(src); rmdir(tmpdir);
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return -1;
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}
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const char *base = strrchr(src, '/');
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base = base ? base + 1 : src;
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char outbin[128];
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snprintf(outbin, sizeof outbin, "%s/%s", tmpdir, base);
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char *dot = strrchr(outbin, '.');
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if (dot && strcmp(dot, ".ww") == 0) *dot = '\0';
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int got = runwait(outbin);
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unlink(src); unlink(outbin); rmdir(tmpdir);
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return got;
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}
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/* asm_byte_identical — the guard lands in BOTH stages, so cstage vs
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* wwstage text output must stay byte-for-byte identical on every row. */
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static int
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asm_byte_identical(const char *bin, const struct row *r, int i)
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{
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char src[64], cs[64], ws[64], cmd[1024];
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snprintf(src, sizeof src, "/tmp/wcmgf_asm_%d_%d.ww", getpid(), i);
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snprintf(cs, sizeof cs, "/tmp/wcmgf_asm_%d_%d_c.s", getpid(), i);
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snprintf(ws, sizeof ws, "/tmp/wcmgf_asm_%d_%d_w.s", getpid(), i);
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FILE *f = fopen(src, "wb");
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if (!f) return -1;
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fputs(r->src, f);
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fclose(f);
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snprintf(cmd, sizeof cmd, "%s/w6c -o %s %s 2>/dev/null", bin, cs, src);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "row[%s]: w6c errored\n", r->label);
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unlink(src);
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return -1;
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}
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snprintf(cmd, sizeof cmd, "%s/w6c_ww -o %s %s 2>/dev/null",
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bin, ws, src);
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if (runwait(cmd) != 0) {
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fprintf(stderr, "row[%s]: w6c_ww errored\n", r->label);
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unlink(src); unlink(cs);
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return -1;
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}
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FILE *fc = fopen(cs, "rb");
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FILE *fw = fopen(ws, "rb");
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int rc = 0;
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if (!fc || !fw) {
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rc = -1;
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} else {
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||||
for (;;) {
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||||
int a = fgetc(fc);
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int b = fgetc(fw);
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if (a != b) { rc = -1; break; }
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if (a == EOF) break;
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}
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}
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if (fc) fclose(fc);
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if (fw) fclose(fw);
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if (rc != 0)
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fprintf(stderr, "row[%s]: cstage vs wwstage asm differs\n",
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||||
r->label);
|
||||
unlink(src); unlink(cs); unlink(ws);
|
||||
return rc;
|
||||
}
|
||||
|
||||
int
|
||||
main(void)
|
||||
{
|
||||
const char *bin = getenv("BIN");
|
||||
if (!bin) bin = "out/bin";
|
||||
char absbin[512];
|
||||
if (bin[0] != '/') {
|
||||
char cwd[256];
|
||||
if (getcwd(cwd, sizeof cwd) == NULL) return 1;
|
||||
snprintf(absbin, sizeof absbin, "%s/%s", cwd, bin);
|
||||
bin = absbin;
|
||||
}
|
||||
|
||||
char cdrv[640];
|
||||
snprintf(cdrv, sizeof cdrv, "%s/ww", bin);
|
||||
char wdrv[640];
|
||||
snprintf(wdrv, sizeof wdrv, "%s/ww_ww", bin);
|
||||
|
||||
struct { const char *name; const char *path; int gated_on_existence; }
|
||||
drivers[] = {
|
||||
{ "cstage", cdrv, 0 },
|
||||
{ "wwstage", wdrv, 1 },
|
||||
{ NULL, NULL, 0 },
|
||||
};
|
||||
|
||||
int n = (int)(sizeof rows / sizeof rows[0]);
|
||||
int total = 0, fail = 0;
|
||||
|
||||
for (int d = 0; drivers[d].name; d++) {
|
||||
if (drivers[d].gated_on_existence
|
||||
&& access(drivers[d].path, X_OK) != 0) {
|
||||
fprintf(stderr, "match_global_field: skip %s (no %s)\n",
|
||||
drivers[d].name, drivers[d].path);
|
||||
continue;
|
||||
}
|
||||
for (int i = 0; i < n; i++) {
|
||||
int got = run_driver(drivers[d].path, &rows[i], i);
|
||||
total++;
|
||||
if (got != rows[i].want) {
|
||||
fprintf(stderr,
|
||||
"match_global_field[%s][%s]: exit=%d want=%d\n",
|
||||
drivers[d].name, rows[i].label,
|
||||
got, rows[i].want);
|
||||
fail++;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (access(wdrv, X_OK) == 0) {
|
||||
for (int i = 0; i < n; i++) {
|
||||
total++;
|
||||
if (asm_byte_identical(bin, &rows[i], i) != 0)
|
||||
fail++;
|
||||
}
|
||||
}
|
||||
|
||||
if (fail) {
|
||||
fprintf(stderr,
|
||||
"match_global_field: %d/%d fixtures failed\n",
|
||||
fail, total);
|
||||
return 1;
|
||||
}
|
||||
printf("match_global_field: %d/%d ok\n", total, total);
|
||||
return 0;
|
||||
}
|
||||
Reference in New Issue
Block a user