add tagged unions

1 files changed, 50 insertions, 4 deletions

diff --git a/bootstrap/cgen.c b/bootstrap/cgen.c
index df5ccbc..8bea8bc 100644
--- a/bootstrap/cgen.c
+++ b/bootstrap/cgen.c
@@ -153,6 +153,20 @@ geniniex(struct expr *ex) {
 }
 
 static void
+geneuiniex(struct expr *ex) {
+   if (ex->t == Ezeroini)
+      pri("{0}");
+   else {
+      assert(ex->t == Eeuini);
+      if (ex->euini.ini)
+      pri("{ /* %s */ %I, .u.%s = %e }", ex->euini.fnam, ex->euini.tag,
+            ex->euini.fnam, ex->euini.ini);
+      else 
+         pri("{ /* %s */ %I }", ex->euini.fnam, ex->euini.tag);
+   }
+}
+
+static void
 genexpr(struct expr *ex) {
    const struct type *ty = unconstify(ex->ty);
    struct decl *decl;
@@ -237,7 +251,7 @@ genexpr(struct expr *ex) {
    case Eget:
       pri("%e%s%s", ex->get.lhs, ex->get.lhs->ty->t == TYptr ? "->" : ".", ex->get.fld);
       break;
-  case Emcall:
+   case Emcall:
       decl = container_of(ex->mcall.met, struct decl, fn);
       assert(*decl->_cname);
       pri("%s(", *decl->_cname);
@@ -248,7 +262,7 @@ genexpr(struct expr *ex) {
       }
       pri(")");
       break;
-  case Eslice:
+   case Eslice:
       ;static int id;
       // TODO range assertions
       pri("({ %t __start%d = %e; ",  ex->slice.start->ty, id, ex->slice.start);
@@ -256,9 +270,14 @@ genexpr(struct expr *ex) {
             ex->ty, ex->slice.lhs, ex->slice.lhs->ty->t == TYslice ? ".ptr" : "", id, ex->slice.end, id);
       ++id;
       break;
-  case Elen:
+   case Elen:
       pri("%e.len", ex->child);
       break;
+   case Eeuini:
+      pri("((%t)", ty);
+      geneuiniex(ex);
+      pri(")");
+      break;
    }
 }
 
@@ -285,10 +304,12 @@ genstmt(struct stmt *stmt) {
          pri("%t %s_%d", decl.var.ty, decl.name, decl.var.id);
          if (decl.var.ini) {
             pri(" = ");
-            if ((decl.var.ty->t == TYstruct || decl.var.ty->t == TYarr)
+            if ((decl.var.ty->t == TYstruct || decl.var.ty->t == TYunion || decl.var.ty->t == TYarr)
               && (decl.var.ini->t == Ezeroini || decl.var.ini->t == Eini))
             {
                geniniex(decl.var.ini);
+            } else if (decl.var.ty->t == TYeunion) {
+               geneuiniex(decl.var.ini);
             } else {
                pri("%e", decl.var.ini);
             }
@@ -425,6 +446,9 @@ liftnestedex(struct expr *ex) {
       liftnestedex(ex->slice.start);
       liftnestedex(ex->slice.end);
       break;
+    case Eeuini:
+      liftnestedex(ex->euini.ini);
+      break;
    }
 }
 
@@ -631,6 +655,28 @@ defctype(const struct type *ty, void *_) {
          liftdecl(ty->agg.decls.d[i]);
       break;
    case TYeunion:
+      if (ty->konst) {
+         defctype(unconstify(ty), NULL);
+         *cname = (char *)unconstify(ty)->_cname;
+         break;
+      }
+      *cname = xasprintf("__ty%s%d", ty->agg.name ? ty->agg.name : "", id++);
+      pri("typedef struct %s %s;\n", *cname, *cname);
+      if (!ty->agg.fwd) {
+         pri("struct %s {\n", *cname);
+         pri("%t t;\n", ty->agg.enumty);
+         pri("union {\n", ty->agg.enumty);
+         for (int i = 0; i < ty->agg.flds.n; ++i) {
+            struct aggfield *fld = &ty->agg.flds.d[i];
+            if (fld->ty)
+               pri("%t %s;\n", fld->ty, fld->name);
+         }
+         pri("} u;\n};\n");
+         pri("_Static_assert(sizeof(%s) == %U, \"sizeof(%t) == %U\");\n",
+               *cname, (u64)ty->size, ty, (u64)ty->size);
+         pri("_Static_assert(__alignof__(%s) == %U, \"__alignof__(%t) == %U\");\n",
+               *cname, (u64)ty->align, ty, (u64)ty->align);
+      }
       break;
    }