selfhost+test: prefer same-module aliaslookup match (#27)
wwstage UNDER — aliaslookup's leaf-only first-match walk let a
cross-module leaf collision (`type invalid = !i32;` ahead of
`type invalid = !void;` in c.aliases) shadow module M's own
alias. Silent-correct-by-zero-init: the let-decl prologue zeroed
the slot 8B-wide (typeis8byteprimitive's void-aliased path,
post-#22), so MOVSXD on the misresolved !i32 produced the right
value while diverging from cstage's MOVQ — bootstrap byte-id
held until any caller bumped the alias-chain ordering. Mirrors
cstage scope_lookup_prefer (cmd/wcc/check.c:65); module-
qualified pkg.alias path unchanged.
Polarity catalog: wwstage UNDER — aliaslookup missing module-
preferring scope discipline. Convergence wwstage → cstage's
resolver pattern (rule 10; cstage already correct via
scope_lookup_prefer). Two-pass walk: same-module first, then
existing first-match fallback. Sea-of-stars shape preserved.
Surfaced by lib/strings landing: utf8's `type invalid = !void;`
and strconv's `type invalid = !i32;` registered in the same flat
c.aliases under one combined.ww, with strconv's later-registered
entry sitting at the head of the chain. utf8.next/decode's
`return e;` (e: invalid) packed via MOVSXD instead of MOVQ. Four
sites in main.s, contributing to 993/995 byte-id divergence in
the wwstage rebuild path.
Tests:
- 726_alias_leaf_collision row 1 pins MOVQ post-zero-init on
both stages and cstage↔wwstage cmp -s byte-id for the
`(invalid:!void via beta)` shape with `alpha.invalid = !i32`
seeded ahead in c.aliases. Sentinel-flip-verified: revert →
wwstage emits MOVSXD post-zero-init + cmp diverges.
- Row 2 (i32_local_read_keeps_movsxd) gates against future
symptom-fix attempts: legitimate `let i: i32; return (i:i64);`
must still emit MOVSXD on both stages (>=2 narrow signed loads
in the promote fn TEXT). Independent of the aliaslookup fix.
98/98 ok. 995_self_rebuild stays green (ww2==ww3==ww4 byte-id).
This commit is contained in:
5
Makefile
5
Makefile
@@ -254,6 +254,7 @@ TESTS = $(BIN)/test_smoke $(BIN)/test_lex $(BIN)/test_parse $(BIN)/test_check \
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$(BIN)/test_composite_call_arg_run \
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$(BIN)/test_letdecl_zeroinit \
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$(BIN)/test_nested_if_labels \
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$(BIN)/test_alias_leaf_collision \
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$(BIN)/test_param_shadow_mod \
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$(BIN)/test_localoff_scope \
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$(BIN)/test_cast_enum_movl \
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@@ -577,6 +578,10 @@ $(BIN)/test_nested_if_labels: test/wcc/725_nested_if_labels.c \
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$(BIN)/w6c $(BIN)/w6c_ww | $(BIN)
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$(CC) $(CFLAGS) -o $@ $<
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$(BIN)/test_alias_leaf_collision: test/wcc/726_alias_leaf_collision.c \
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$(BIN)/w6c $(BIN)/w6c_ww | $(BIN)
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$(CC) $(CFLAGS) -o $@ $<
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$(BIN)/test_use_promote_alias: test/wcc/699_use_promote_alias.c \
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$(BIN)/ww $(BIN)/w6c $(BIN)/w6a $(BIN)/w6l \
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$(LIB)/libwwrt.a | $(BIN)
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@@ -18206,10 +18206,23 @@ fn collectaliases(c: *cgen, file: *node) void = {
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};
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fn aliaslookup(c: *cgen, name: str) *node = {
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// Same-module first, then any. Mirrors cstage's scope_lookup_prefer
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// (cmd/wcc/check.c:65); without the prefer pass a bare `invalid`
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// in module M with `type invalid = !void;` can collapse onto a
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// strconv-style `type invalid = !i32;` registered earlier in
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// c.aliases (head-first walk). The leaf-collision then drives a
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// narrow MOVSXD load of a slot the let-decl zero-inits 8B-wide
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// (task #27 silent-correct-by-zero-init).
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let a: *aliasent = c.aliases;
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for (a != nil) {
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let an: str = a.aname;
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if (streq(an, name)) { return a.target; };
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if (streq(a.aname, name)) {
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if (streq(a.amod, c.curmod)) { return a.target; };
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};
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a = a.aanext;
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};
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a = c.aliases;
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for (a != nil) {
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if (streq(a.aname, name)) { return a.target; };
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a = a.aanext;
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};
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// Module-qualified form: `pkg.alias` → match the leaf name
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@@ -73,10 +73,23 @@ fn collectaliases(c: *cgen, file: *node) void = {
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};
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fn aliaslookup(c: *cgen, name: str) *node = {
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// Same-module first, then any. Mirrors cstage's scope_lookup_prefer
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// (cmd/wcc/check.c:65); without the prefer pass a bare `invalid`
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// in module M with `type invalid = !void;` can collapse onto a
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// strconv-style `type invalid = !i32;` registered earlier in
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// c.aliases (head-first walk). The leaf-collision then drives a
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// narrow MOVSXD load of a slot the let-decl zero-inits 8B-wide
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// (task #27 silent-correct-by-zero-init).
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let a: *aliasent = c.aliases;
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for (a != nil) {
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let an: str = a.aname;
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if (streq(an, name)) { return a.target; };
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if (streq(a.aname, name)) {
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if (streq(a.amod, c.curmod)) { return a.target; };
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};
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a = a.aanext;
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};
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a = c.aliases;
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for (a != nil) {
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if (streq(a.aname, name)) { return a.target; };
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a = a.aanext;
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};
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// Module-qualified form: `pkg.alias` → match the leaf name
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@@ -18206,10 +18206,23 @@ fn collectaliases(c: *cgen, file: *node) void = {
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};
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fn aliaslookup(c: *cgen, name: str) *node = {
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// Same-module first, then any. Mirrors cstage's scope_lookup_prefer
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// (cmd/wcc/check.c:65); without the prefer pass a bare `invalid`
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// in module M with `type invalid = !void;` can collapse onto a
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// strconv-style `type invalid = !i32;` registered earlier in
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// c.aliases (head-first walk). The leaf-collision then drives a
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// narrow MOVSXD load of a slot the let-decl zero-inits 8B-wide
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// (task #27 silent-correct-by-zero-init).
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let a: *aliasent = c.aliases;
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for (a != nil) {
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let an: str = a.aname;
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if (streq(an, name)) { return a.target; };
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if (streq(a.aname, name)) {
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if (streq(a.amod, c.curmod)) { return a.target; };
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};
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a = a.aanext;
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};
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a = c.aliases;
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for (a != nil) {
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if (streq(a.aname, name)) { return a.target; };
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a = a.aanext;
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};
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// Module-qualified form: `pkg.alias` → match the leaf name
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277
test/wcc/726_alias_leaf_collision.c
Normal file
277
test/wcc/726_alias_leaf_collision.c
Normal file
@@ -0,0 +1,277 @@
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/*
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* 726_alias_leaf_collision — sentinel for #27. Pins wwstage's
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* aliaslookup to a same-module-first leaf walk so a bare `invalid`
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* inside module M (with `type invalid = !void;`) resolves to M's
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* underlying void, not to some other module's `type invalid = !i32;`
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* registered later in c.aliases.
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*
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* Pre-fix wwstage's `aliaslookup` (selfhost/cmd/wcc/cgen.ww) walked
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* c.aliases head-first by leaf name, returning the FIRST match. With
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* combined-source build orderings where a `type invalid = !i32;` from
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* lib/strconv sits ahead of utf8's `type invalid = !void;` in the
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* chain, `localloadop` resolved invalid → !i32 (size 4, signed) and
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* emitted MOVSXD on a slot the let-decl prologue zero-inited 8B-wide
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* (typeis8byteprimitive walks to void → MOVQ $0). Silent-correct-by-
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* zero-init: the upper 4B happened to be zero from the zero-init, so
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* the 4B sign-extend produced the right value, but the asm diverged
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* from cstage's MOVQ and 995_self_rebuild broke once any caller of
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* lib/strings/strings.byteindex (the (str|rune) match-arm shape that
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* dragged utf8 into the bootstrap closure) bumped the alias-chain
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* ordering.
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*
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* Cstage's `resolve_typename` (cmd/wcc/check.c:65) calls
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* `scope_lookup_prefer(cur, cur_mod, nm)` — same-module-first then
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* fallback. The fix mirrors that discipline in wwstage's aliaslookup.
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* Asserts byte-id between cstage and wwstage on a probe shape that
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* loses the asm divergence under the fix.
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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/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 {
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const char *label;
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const char *src;
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/* `want` selects which assertion family runs on the emitted .s:
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* "movq_invalid" — post-zero-init load on beta.yield_more's
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* invalid-slot must be MOVQ (the collision case).
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* "movsxd_i32" — local i32 read in promote must be MOVSXD on
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* BOTH stages. Guards future "fix" attempts
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* that pessimize localloadop and would break
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* legitimate signed-narrow loads. */
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const char *want;
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};
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/* Module ordering picked so the colliding `type invalid = !i32;` lands
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* later in c.aliases (head-prepend → at the head), masking module M's
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* own `type invalid = !void;`. `gamma` brings both modules into scope
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* via use directives so decl_mod tags both as imports — that gates
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* scope_define_in_module's per-mod dedup path on cstage's side. */
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static const struct row rows[] = {
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{ "void_invalid_under_i32_collision",
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"// MODULE: gamma\n"
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"use alpha;\n"
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"use beta;\n"
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"export fn main() i32 = { return 0; };\n"
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"// MODULE: beta\n"
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"type more = void;\n"
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"type invalid = !void;\n"
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"fn yield_more() (rune | more | invalid) = {\n"
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" let e: invalid;\n"
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" return e;\n"
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"};\n"
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"// MODULE: alpha\n"
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"export type invalid = !i32;\n",
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"movq_invalid" },
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/* Regression guard: a real signed-narrow `let i: i32 = ...;` read
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* MUST stay on MOVSXD. Any future "fix" that pessimizes
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* localloadop to blanket-MOVQ in the name of #27 would silently
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* regress this — losing sign-extension on i32 → i64 promotion
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* (also drops the high half of a deref-store-narrowed slot). */
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{ "i32_local_read_keeps_movsxd",
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"fn promote(x: i32) i64 = {\n"
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" let i: i32 = x;\n"
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" return (i: i64);\n"
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"};\n",
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"movsxd_i32" },
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};
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static int
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emit_s(const char *w6c, const struct row *r, int i, char *out_s, size_t cap)
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{
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char src[64], cmd[1024];
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snprintf(src, sizeof src, "/tmp/alc_%d_%d.ww", getpid(), i);
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snprintf(out_s, cap, "/tmp/alc_%d_%d_%s.s",
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getpid(), i, w6c[strlen(w6c) - 1] == 'w' ? "ww" : "c");
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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 -o %s %s 2>/dev/null", w6c, out_s, src);
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int rc = runwait(cmd);
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unlink(src);
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return rc;
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}
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static int
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slurp(const char *path, char *buf, size_t cap)
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{
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FILE *f = fopen(path, "rb");
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if (!f) return -1;
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size_t n = fread(buf, 1, cap - 1, f);
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fclose(f);
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buf[n] = '\0';
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return (int)n;
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}
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/* The yield_more body must read its tagged-return payload through an
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* 8B MOVQ. A MOVSXD on the same slot is the pre-fix silent-correct-
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* by-zero-init shape. */
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static int
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check_movq_after_zeroinit(const char *spath, const struct row *r,
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const char *stage)
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{
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char buf[1 << 14];
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if (slurp(spath, buf, sizeof buf) < 0) {
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fprintf(stderr, "row[%s][%s]: cannot read %s\n",
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r->label, stage, spath);
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return -1;
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}
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const char *fn = strstr(buf, "TEXT beta.yield_more");
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if (!fn) {
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fprintf(stderr, "row[%s][%s]: no TEXT beta.yield_more in %s\n",
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r->label, stage, spath);
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return -1;
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}
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const char *zi = strstr(fn, "MOVQ\t$0, ");
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if (!zi) {
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fprintf(stderr, "row[%s][%s]: no zero-init store\n",
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r->label, stage);
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return -1;
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}
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const char *bad = strstr(zi, "MOVSXD\t");
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const char *good = strstr(zi, "\n\tMOVQ\t-");
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const char *ret = strstr(zi, "RET");
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if (bad && (ret == NULL || bad < ret)) {
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fprintf(stderr,
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"row[%s][%s]: post-zero-init slot read uses MOVSXD\n",
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r->label, stage);
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return -1;
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}
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if (!good || (ret && good > ret)) {
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fprintf(stderr,
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"row[%s][%s]: post-zero-init slot read missing MOVQ\n",
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r->label, stage);
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return -1;
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}
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return 0;
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}
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/* Real i32 local read MUST stay MOVSXD. Any MOVQ load of `i` (the
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* narrow signed local) inside promote means a later "fix" pessimized
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||||
* localloadop and silently dropped sign-extension. */
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static int
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||||
check_movsxd_kept(const char *spath, const struct row *r, const char *stage)
|
||||
{
|
||||
char buf[1 << 14];
|
||||
if (slurp(spath, buf, sizeof buf) < 0) {
|
||||
fprintf(stderr, "row[%s][%s]: cannot read %s\n",
|
||||
r->label, stage, spath);
|
||||
return -1;
|
||||
}
|
||||
const char *fn = strstr(buf, "TEXT promote");
|
||||
if (!fn) {
|
||||
fprintf(stderr, "row[%s][%s]: no TEXT promote in %s\n",
|
||||
r->label, stage, spath);
|
||||
return -1;
|
||||
}
|
||||
const char *ret = strstr(fn, "RET");
|
||||
const char *bp = fn;
|
||||
int sxd = 0;
|
||||
for (;;) {
|
||||
const char *p = strstr(bp, "MOVSXD\t-");
|
||||
if (!p || (ret && p > ret)) break;
|
||||
sxd++;
|
||||
bp = p + 1;
|
||||
}
|
||||
if (sxd < 2) {
|
||||
fprintf(stderr,
|
||||
"row[%s][%s]: expected MOVSXD on i32 local reads, found %d\n",
|
||||
r->label, stage, sxd);
|
||||
return -1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
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 w6c[640], w6c_ww[640];
|
||||
snprintf(w6c, sizeof w6c, "%s/w6c", bin);
|
||||
snprintf(w6c_ww, sizeof w6c_ww, "%s/w6c_ww", bin);
|
||||
|
||||
int have_ww = (access(w6c_ww, X_OK) == 0);
|
||||
int n = (int)(sizeof rows / sizeof rows[0]);
|
||||
int total = 0, fail = 0;
|
||||
|
||||
for (int i = 0; i < n; i++) {
|
||||
char cs_path[128], ws_path[128];
|
||||
|
||||
if (emit_s(w6c, &rows[i], i, cs_path, sizeof cs_path) != 0) {
|
||||
fprintf(stderr,
|
||||
"alias_leaf_collision[cstage][%s]: w6c failed\n",
|
||||
rows[i].label);
|
||||
fail++; total++; continue;
|
||||
}
|
||||
total++;
|
||||
int rc;
|
||||
if (strcmp(rows[i].want, "movsxd_i32") == 0) {
|
||||
rc = check_movsxd_kept(cs_path, &rows[i], "cstage");
|
||||
} else {
|
||||
rc = check_movq_after_zeroinit(cs_path, &rows[i], "cstage");
|
||||
}
|
||||
if (rc != 0) fail++;
|
||||
|
||||
if (!have_ww) { unlink(cs_path); continue; }
|
||||
|
||||
if (emit_s(w6c_ww, &rows[i], i, ws_path, sizeof ws_path) != 0) {
|
||||
fprintf(stderr,
|
||||
"alias_leaf_collision[wwstage][%s]: w6c_ww failed\n",
|
||||
rows[i].label);
|
||||
fail++; total++;
|
||||
unlink(cs_path); continue;
|
||||
}
|
||||
total++;
|
||||
if (strcmp(rows[i].want, "movsxd_i32") == 0) {
|
||||
rc = check_movsxd_kept(ws_path, &rows[i], "wwstage");
|
||||
} else {
|
||||
rc = check_movq_after_zeroinit(ws_path, &rows[i], "wwstage");
|
||||
}
|
||||
if (rc != 0) fail++;
|
||||
|
||||
/* byte-id between stages on the same input — the principled
|
||||
* sentinel for the polarity catalog. */
|
||||
total++;
|
||||
char cmd[512];
|
||||
snprintf(cmd, sizeof cmd, "cmp -s %s %s", cs_path, ws_path);
|
||||
if (runwait(cmd) != 0) {
|
||||
fprintf(stderr,
|
||||
"alias_leaf_collision[%s]: cstage vs wwstage asm differs\n",
|
||||
rows[i].label);
|
||||
fail++;
|
||||
}
|
||||
|
||||
unlink(cs_path); unlink(ws_path);
|
||||
}
|
||||
|
||||
if (fail) {
|
||||
fprintf(stderr,
|
||||
"alias_leaf_collision: %d/%d fixtures failed\n", fail, total);
|
||||
return 1;
|
||||
}
|
||||
printf("alias_leaf_collision: %d/%d ok\n", total, total);
|
||||
return 0;
|
||||
}
|
||||
Reference in New Issue
Block a user