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Work towards codegen for unions

--- a/8/reduce.c

+++ b/8/reduce.c

@@ -55,9 +55,18 @@

 static Node *one;

 static Node *zero;

 static Node *ptrsz;

+static Node *wordsz;

 static Type *tyword;

 static Type *tyvoid;

+static int max(int a, int b)

+{

+    if (a > b)

+        return a;

+    else

+        return b;

+}

+

 static Type *base(Type *t)

 {

     assert(t->nsub == 1);

@@ -195,6 +204,8 @@

     size_t i;

     sz = 0;

+    if (!t)

+        return 0;

     switch (t->type) {

         case Tyvoid:

             die("void has no size");

@@ -235,7 +246,9 @@

             return sz;

             break;

         case Tyunion:

-            die("Sizes for composite types not implemented yet");

+            sz = Wordsz;

+            for (i = 0; i < t->nmemb; i++)

+                sz = max(sz, tysize(t->udecls[i]->etype) + Wordsz);

             break;

         case Tybad: case Tyvar: case Typaram: case Tyname: case Ntypes:

             die("Type %s does not have size; why did it get down to here?", tystr(t));

@@ -564,6 +577,42 @@

     return r;

 }

+static Node *lowerucon(Simp *s, Node *n)

+{

+    Node *tmp, *u, *tag, *elt, *sz;

+    Node *r;

+    Type *ty;

+    Ucon *uc;

+    size_t i;

+

+    /* find the ucon we're constructing here */

+    ty = tybase(n->expr.type);

+    for (i = 0; i < ty->nmemb; i++) {

+        if (!strcmp(namestr(n->expr.args[0]), namestr(ty->udecls[i]->name))) {

+            uc = ty->udecls[i];

+            break;

+        }

+    }

+

+    tmp = temp(s, n);

+    u = addr(tmp, exprtype(n));

+    tag = word(n->line, uc->id);

+    store(u, tag);

+    if (!uc->etype)

+        return tmp;

+

+    elt = rval(s, n->expr.args[1]);

+    u = add(u, wordsz);

+    if (tysize(uc->etype) > Wordsz) {

+        elt = addr(elt, uc->etype);

+        sz = word(n->line, tysize(uc->utype));

+        r = mkexpr(n->line, Oblit, u, elt, sz, NULL);

+    } else {

+        r = store(u, elt);

+    }

+    return tmp;

+}

+

 static Node *rval(Simp *s, Node *n)

 {

     Node *r; /* expression result */

@@ -613,6 +662,9 @@

                 r = load(t);

             }

             break;

+        case Ocons:

+            r = lowerucon(s, n);

+            break;

         case Ocast:

             /* slice -> ptr cast */

             r = lowercast(s, n);

@@ -935,6 +987,7 @@

     one = word(-1, 1);

     zero = word(-1, 0);

     ptrsz = word(-1, Wordsz);

+    wordsz = word(-1, Wordsz);

     fn = NULL;

     nfn = 0;

--- a/parse/infer.c

+++ b/parse/infer.c

@@ -99,8 +99,11 @@

     } else if (t->type == Tyunion) {

         for (i = 0; i < t->nmemb; i++) {

             tyresolve(t->udecls[i]->utype);

-            if (t->udecls[i]->etype)

+            t->udecls[i]->utype = tf(t->udecls[i]->utype);

+            if (t->udecls[i]->etype) {

                 tyresolve(t->udecls[i]->etype);

+                t->udecls[i]->etype = tf(t->udecls[i]->etype);

+            }

         }

     } else if (t->type == Tyarray) {

         infernode(t->asize, NULL, NULL);

@@ -710,7 +713,7 @@

 {

 }

-/* returns the fixal type for t, after all unifications

+/* returns the final type for t, after all unifications

  * and default constraint selections */

 static Type *tyfix(Node *ctx, Type *t)

 {

@@ -726,8 +729,17 @@

         if (hascstr(t, cstrtab[Tcint]) || cstrcheck(t, tyint))

             return tyint;

     } else {

-        if (t->type == Tyarray)

+        if (t->type == Tyarray) {

             typesub(t->asize);

+        } else if (t->type == Tystruct) {

+            for (i = 0; i < t->nmemb; i++)

+                typesub(t->sdecls[i]);

+        } else if (t->type == Tyunion) {

+            for (i = 0; i < t->nmemb; i++) {

+                if (t->udecls[i]->etype)

+                    t->udecls[i]->etype = tyfix(ctx, t->udecls[i]->etype);

+            }

+        }

         for (i = 0; i < t->nsub; i++)

             t->sub[i] = tyfix(ctx, t->sub[i]);

     }

@@ -875,7 +887,7 @@

     }

 }

-void mergeexports(Node *file)

+static void mergeexports(Node *file)

 {

     Stab *exports, *globls;

     size_t i, nk;

@@ -925,7 +937,7 @@

     popstab();

 }

-void specialize(Node *f)

+static void specialize(Node *f)

 {

     Node *d, *name;

     size_t i;

--- a/parse/specialize.c

+++ b/parse/specialize.c

@@ -235,7 +235,7 @@

     return r;

 }

-size_t tidappend(char *buf, size_t sz, Type *t)

+static size_t tidappend(char *buf, size_t sz, Type *t)

 {

     char *p;

     char *end;

@@ -249,7 +249,7 @@

     return end - p;

 }

-Node *genericname(Node *n, Type *t)

+static Node *genericname(Node *n, Type *t)

 {

     char buf[1024];

     char *p;

-- 

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