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compiler: implement blank package name semantics

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Hojun-Cho
2026-08-23 15:33:59 +09:00
parent e67b8e1bc4
commit 0b24b11d65
14 changed files with 2862 additions and 112 deletions
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88
cmd/wcc/check.c
View File

@@ -62,6 +62,8 @@ static const char *use_path(Node *file, const char *curmod, int source,
const char *alias);
static const char *find_use_path(Node *file, const char *curmod, int source,
const char *alias, int mark);
static Node *find_use_binding(Node *file, const char *curmod, int source,
const char *alias, int mark);
static int src_imports(Node *file, const char *modtag, int source,
const char *name);
static Sym *lookup_visible(Checker *c, const char *name);
@@ -96,6 +98,11 @@ resolve_typename(Checker *c, Node *n)
char *head = astrndup(c->a, nm, hl);
Sym *m = scope_lookup(c->cur, head);
if (m && (m->kind == SK_USE || m->use_alias)) {
Node *u = find_use_binding(c->file, c->cur_mod,
c->cur_source, head, 1);
if (u != NULL && u->usepkgname != NULL
&& strcmp(u->usepkgname, "_") == 0)
return ty_err;
/* M1 #22: map the qualifier alias to its dotted
* import path (symbols are path-keyed). */
const char *mk = use_path(c->file, c->cur_mod,
@@ -1521,6 +1528,11 @@ cexpr(Checker *c, Node *n)
if (n->lhs && n->lhs->kind == N_IDENT) {
Sym *ms = lookup_visible(c, n->lhs->str);
if (ms && (ms->kind == SK_USE || ms->use_alias)) {
Node *u = find_use_binding(c->file, c->cur_mod,
c->cur_source, n->lhs->str, 1);
if (u != NULL && u->usepkgname != NULL
&& strcmp(u->usepkgname, "_") == 0)
return n->type = ty_err;
/* Module-qualified ref. `use_alias` covers
* the self-import case where the module's
* type name shadowed the SK_USE; the leaf
@@ -3016,6 +3028,18 @@ import_binding_pos(Node *u)
return p;
}
static Pos
import_path_pos(Node *u)
{
Pos p = u->pos;
if (u->usepathfile != NULL) {
p.file = u->usepathfile;
p.line = u->usepathline;
p.col = u->usepathcol;
}
return p;
}
/*
* use_path — map a source-file default qualifier (the imported package's
* declared name) to the full canonical import path it binds, for
@@ -3056,6 +3080,33 @@ find_use_path(Node *file, const char *curmod, int source, const char *alias,
return NULL;
}
static Node *
find_use_binding(Node *file, const char *curmod, int source,
const char *alias, int mark)
{
if (file == NULL || alias == NULL) return NULL;
/* Source-zero self-qualification wins before import lookup in
* find_use_path and therefore cannot denote an imported package object. */
if (source == 0 && curmod != NULL) {
const char *dot = strrchr(curmod, '.');
const char *leaf = dot ? dot + 1 : curmod;
if (strcmp(alias, leaf) == 0) return NULL;
}
for (Node *u = file->list; u; u = u->next) {
if (u->kind != N_USE || u->str == NULL || invalid_init_import(u)
|| u->sourceid != source || strcmp(u->str, alias) != 0)
continue;
const char *um = decl_mod(file, u);
int same = (um == NULL) ? (curmod == NULL)
: (curmod != NULL && strcmp(um, curmod) == 0);
if (same) {
if (mark) u->used = 1;
return u;
}
}
return NULL;
}
static const char *
use_path(Node *file, const char *curmod, int source, const char *alias)
{
@@ -4379,11 +4430,48 @@ check_test_target(const Checker *c, const char *path)
return 0;
}
static void
reject_blank_package_names(Checker *c, Node *file)
{
for (Node *p = file->body; p; p = p->next)
if (p->kind == N_FILE && p->pkgname != NULL
&& strcmp(p->pkgname, "_") == 0)
err(c, p->pos, "invalid package name _");
}
static void
reject_invalid_imports(Checker *c, Node *file)
{
for (Node *u = file->list; u; u = u->next) {
if (u->kind != N_USE || u->usepath == NULL
|| u->usepkgname == NULL
|| strcmp(u->usepkgname, "_") != 0)
continue;
u->used = 1;
int seen = 0;
for (Node *v = file->list; v != u; v = v->next) {
if (v->kind == N_USE && v->usepath != NULL
&& v->usepkgname != NULL
&& strcmp(v->usepkgname, "_") == 0
&& strcmp(v->usepath, u->usepath) == 0) {
seen = 1;
break;
}
}
if (!seen)
err(c, import_path_pos(u),
"could not import %s (invalid package name: \"_\")",
u->usepath);
}
}
void
check_file(Checker *c, Node *file)
{
if (file == NULL || file->kind != N_FILE) return;
c->file = file;
reject_blank_package_names(c, file);
reject_invalid_imports(c, file);
/* Under -T, prepend the dispatcher support import before pass 1 so
* decl_mod keys the runner under the selected support module. A pure

46
cmd/wcc/parse.c
View File

@@ -92,6 +92,24 @@ expectident(Parser *p)
return s;
}
/* Package declarations admit the blank identifier syntactically. Keep this
* private to the package-name slot: every ordinary identifier production must
* retain expectident's rejection of TK_UNDER. The checker owns the semantic
* BlankPkgName rejection. */
static const char *
expectpackagename(Parser *p)
{
if (p->cur.kind != TK_IDENT && p->cur.kind != TK_UNDER) {
errorf(p->cur.pos, "expected identifier, got %s",
tokname(p->cur.kind));
p->errs++;
return "<err>";
}
const char *s = p->cur.text;
advance(p);
return s;
}
/* Like expectident but also accepts a bare `_` discard marker. The
* returned string is the empty string "" so the checker skips
* scope_define. Callers that care can detect this with `s[0] == '\0'`. */
@@ -1340,19 +1358,25 @@ parseuse(Parser *p)
n->usefile = p->cur.pos.file;
n->useline = p->cur.pos.line;
n->usecol = p->cur.pos.col;
Pos pathpos = p->cur.pos;
const char *alias = NULL;
const char *first;
if (p->cur.kind == TK_UNDER) {
n->useblank = 1;
advance(p);
pathpos = p->cur.pos;
first = expectident(p);
} else {
first = expectident(p);
if (p->cur.kind == TK_IDENT) {
alias = first;
pathpos = p->cur.pos;
first = expectident(p);
}
}
n->usepathfile = pathpos.file;
n->usepathline = pathpos.line;
n->usepathcol = pathpos.col;
const char *leaf = first;
const char *path = leaf;
while (accept(p, TK_DOT)) {
@@ -1383,11 +1407,13 @@ parseheaderuse(Parser *p)
n->usefile = p->cur.pos.file;
n->useline = p->cur.pos.line;
n->usecol = p->cur.pos.col;
Pos pathpos = p->cur.pos;
const char *alias = NULL;
const char *first;
if (p->cur.kind == TK_UNDER) {
n->useblank = 1;
advance(p);
pathpos = p->cur.pos;
} else if (p->cur.kind != TK_IDENT) {
errorf(p->cur.pos, "expected identifier, got %s",
tokname(p->cur.kind));
@@ -1404,9 +1430,13 @@ parseheaderuse(Parser *p)
advance(p);
if (!n->useblank && p->cur.kind == TK_IDENT) {
alias = first;
pathpos = p->cur.pos;
first = p->cur.text;
advance(p);
}
n->usepathfile = pathpos.file;
n->usepathline = pathpos.line;
n->usepathcol = pathpos.col;
const char *leaf = first;
const char *path = leaf;
while (p->cur.kind == TK_DOT) {
@@ -1467,13 +1497,12 @@ parsepackageheader(Parser *p)
}
Pos pp = p->cur.pos;
advance(p);
if (p->cur.kind != TK_IDENT) {
if (p->cur.kind != TK_IDENT && p->cur.kind != TK_UNDER) {
errorf(p->cur.pos, "invalid or missing package clause");
p->errs++;
return file;
}
const char *name = p->cur.text;
advance(p);
const char *name = expectpackagename(p);
if (p->cur.kind != TK_SEMI) {
errorf(p->cur.pos, "expected ';' after package name");
p->errs++;
@@ -1548,14 +1577,14 @@ parseimports(Parser *p)
Pos pp = p->cur.pos;
previmport = 1;
advance(p);
if (p->cur.kind != TK_IDENT) {
if (p->cur.kind != TK_IDENT && p->cur.kind != TK_UNDER) {
errorf(p->cur.pos, "invalid or missing package clause");
p->errs++;
sawpackage = 1;
skipdecl(p);
continue;
}
const char *name = expectident(p);
const char *name = expectpackagename(p);
expect(p, TK_SEMI);
p->curpkg = name;
if (p->pathmod == NULL && p->resetmod == NULL)
@@ -1754,13 +1783,16 @@ parsefile(Parser *p)
sawpackage = 1;
previmport = 1;
advance(p);
const char *name = expectident(p);
Pos namepos = p->cur.pos;
const char *name = expectpackagename(p);
expect(p, TK_SEMI);
p->curpkg = name;
if (p->pathmod == NULL && p->resetmod == NULL) {
p->curmod = name;
}
Node *package = newnode(p->a, N_FILE, packagepos);
Pos markerpos = strcmp(name, "_") == 0
? namepos : packagepos;
Node *package = newnode(p->a, N_FILE, markerpos);
package->module = p->curmod;
package->pkgname = name;
package->sourceid = p->sourceid;

4
cmd/wcc/ww.h
View File

@@ -354,6 +354,10 @@ struct Node {
* alias when explicit, path otherwise. */
int useline;
int usecol;
const char *usepathfile; /* N_USE: first path-token position,
* independent of an explicit/blank alias. */
int usepathline;
int usepathcol;
const char *usepkgname; /* N_USE: imported declared package name,
* independent of the visible binding in `str`. */
int useblank; /* N_USE: `_` spelling; no source binding. */