diff options
Diffstat (limited to 'parse/specialize.c')
| -rw-r--r-- | parse/specialize.c | 116 |
1 files changed, 110 insertions, 6 deletions
diff --git a/parse/specialize.c b/parse/specialize.c index dce9f00..bdaa65f 100644 --- a/parse/specialize.c +++ b/parse/specialize.c @@ -317,7 +317,9 @@ static Node *specializenode(Node *n, Tysubst *tsmap) r = mknode(n->loc, n->type); switch (n->type) { case Nfile: - case Nuse: die("Node %s not allowed here\n", nodestr[n->type]); break; + case Nuse: + die("Node %s not allowed here\n", nodestr[n->type]); + break; case Nexpr: r->expr.op = n->expr.op; r->expr.type = tysubst(n->expr.type, tsmap); @@ -447,6 +449,107 @@ Node *genericname(Node *n, Type *t) return name; } +/* this doesn't walk through named types, so it can't recurse infinitely. */ +int matchquality(Type *pat, Type *to) +{ + int match, q; + size_t i; + Ucon *puc, *tuc; + + if (pat->type == Typaram) + return 0; + else if (pat->type != to->type) + return -1; + + match = 0; + switch (pat->type) { + case Tystruct: + if (pat->nmemb != to->nmemb) + return -1; + for (i = 0; i < pat->nmemb; i++) { + if (!streq(declname(pat->sdecls[i]),declname( to->sdecls[i]))) + return -1; + q = matchquality(decltype(pat->sdecls[i]), decltype(to->sdecls[i])); + if (q < 0) + return -1; + match += q; + } + break; + case Tyunion: + if (pat->nmemb != to->nmemb) + return -1; + for (i = 0; i < pat->nmemb; i++) { + if (!nameeq(pat->udecls[i], to->udecls[i])) + return -1; + puc = pat->udecls[i]; + tuc = to->udecls[i]; + if (puc->etype && tuc->etype) { + q = matchquality(puc->etype, tuc->etype); + if (q < 0) + return -1; + match += q; + } else if (puc->etype != tuc->etype) { + return -1; + } + } + break; + case Tyname: + if (!nameeq(pat->name, to->name)) + return -1; + if (pat->narg != to->narg) + return -1; + for (i = 0; i < pat->narg; i++) { + q = matchquality(pat->sub[i], to->sub[i]); + if (q < 0) + return -1; + match += q; + } + break; + default: + if (pat->nsub != to->nsub) + break; + if (pat->type == to->type) + match = 1; + for (i = 0; i < pat->nsub; i++) { + q = matchquality(pat->sub[i], to->sub[i]); + if (q < 0) + return -1; + match += q; + } + break; + } + return match; +} + +Node *bestimpl(Node *n, Type *to) +{ + Node **gimpl, **ambig, *match; + size_t ngimpl, nambig, i; + int score; + int best; + + ambig = NULL; + nambig = 0; + best = -1; + gimpl = n->decl.gimpl; + ngimpl = n->decl.ngimpl; + for (i = 0; i < ngimpl; i++) { + score = matchquality(decltype(gimpl[i]), to); + if (score > best) { + lfree(&ambig, &nambig); + best = score; + match = gimpl[i]; + } else if (score == best) { + lappend(&ambig, &nambig, gimpl[i]); + } + } + if (best < 0) + return NULL; + else if (nambig > 0) + fatal(n, "ambiguous implementation for %s", tystr(to)); + return match; +} + /* * Takes a generic declaration, and creates a specialized * duplicate of it with type 'to'. It also generates @@ -471,15 +574,16 @@ Node *specializedcl(Node *g, Type *to, Node **name) if (!st) fatal(n, "Can't find symbol table for %s.%s", n->name.ns, n->name.name); d = getdcl(st, n); - if (debugopt['S']) - printf("depth[%d] specializing [%d]%s => %s\n", stabstkoff, g->loc.line, - namestr(g->decl.name), namestr(n)); if (d) return d; if (g->decl.trait) { - printf("%s\n", namestr(n)); - fatal(g, "no trait implemented for for %s:%s", namestr(g->decl.name), tystr(to)); + g = bestimpl(g, to); + if (!g) + fatal(g, "no trait implemented for for %s:%s", namestr(g->decl.name), tystr(to)); } + if (debugopt['S']) + printf("depth[%d] specializing [%d]%s => %s\n", stabstkoff, g->loc.line, + namestr(g->decl.name), namestr(n)); /* namespaced names need to be looked up in their correct * context. */ if (n->name.ns) |