shithub: mc

Info  •  Files  •  Log  •  Branches

Propagate the constness of expressions.

--- a/6/simp.c

+++ b/6/simp.c

@@ -1474,7 +1474,7 @@

     } else if (!dcl->decl.isconst && !e) {

         lappend(&s->blobs, &s->nblobs, dcl);

     } else {

-        fatal(dcl->line, "Declaration %s initialized with nonconstant value", declname(dcl));

+        die("Non-constant initializer for %s\n", declname(dcl));

     }

 }

--- a/libstd/sys-osx.myr

+++ b/libstd/sys-osx.myr

@@ -1,4 +1,5 @@

 use "types.use"

+use "errno-osx.use"

 pkg std =

 	type scno = int64

--- a/parse/infer.c

+++ b/parse/infer.c

@@ -825,6 +825,7 @@

         fatal(n->line, "Undeclared var %s.%s", nsname->name.ns, nsname->name.name);

     var = mkexpr(n->line, Ovar, nsname, NULL);

     var->expr.did = s->decl.did;

+    var->expr.isconst = s->decl.isconst;

     if (s->decl.isgeneric)

         settype(st, var, tyfreshen(st, s->decl.type));

     else

@@ -960,10 +961,12 @@

     size_t i, nargs;

     Node *s;

     Type *t;

+    int isconst;

     assert(n->type == Nexpr);

     args = n->expr.args;

     nargs = n->expr.nargs;

+    isconst = 1;

     for (i = 0; i < nargs; i++) {

         /* Nlit, Nvar, etc should not be inferred as exprs */

         if (args[i]->type == Nexpr) {

@@ -972,8 +975,11 @@

             if (exprop(args[i]) == Omemb)

                 checkns(st, args[i], &args[i]);

             inferexpr(st, args[i], ret, sawret);

+            isconst = isconst && args[i]->expr.isconst;

         }

     }

+    if (ispureop[exprop(n)])

+        n->expr.isconst = isconst;

     infernode(st, n->expr.idx, NULL, NULL);

     switch (exprop(n)) {

         /* all operands are same type */

@@ -984,8 +990,12 @@

         case Oneg:      /* -@a -> @a */

             t = type(st, args[0]);

             constrain(st, n, type(st, args[0]), cstrtab[Tcnum]);

-            for (i = 1; i < nargs; i++)

+            isconst = args[0]->expr.isconst;

+            for (i = 1; i < nargs; i++) {

+                isconst = isconst && args[i]->expr.isconst;

                 t = unify(st, n, t, type(st, args[i]));

+            }

+            n->expr.isconst = isconst;

             settype(st, n, tf(st, t));

             break;

         case Omod:      /* @a % @a -> @a */

@@ -1012,8 +1022,12 @@

             t = type(st, args[0]);

             constrain(st, n, type(st, args[0]), cstrtab[Tcnum]);

             constrain(st, n, type(st, args[0]), cstrtab[Tcint]);

-            for (i = 1; i < nargs; i++)

+            isconst = args[0]->expr.isconst;

+            for (i = 1; i < nargs; i++) {

+                isconst = isconst && args[i]->expr.isconst;

                 t = unify(st, n, t, type(st, args[i]));

+            }

+            n->expr.isconst = isconst;

             settype(st, n, tf(st, t));

             break;

         case Oasn:      /* @a = @a -> @a */

@@ -1021,6 +1035,8 @@

             for (i = 1; i < nargs; i++)

                 t = unify(st, n, t, type(st, args[i]));

             settype(st, n, tf(st, t));

+            if (args[0]->expr.isconst)

+                fatal(n->line, "Attempting to assign constant \"%s\"", ctxstr(st, args[0]));

             break;

         /* operands same type, returning bool */

@@ -1099,10 +1115,12 @@

             if (!s)

                 fatal(n->line, "Undeclared var %s", ctxstr(st, args[0]));

+            n->expr.isconst = s->decl.isconst;

             if (s->decl.isgeneric)

                 t = tyfreshen(st, tf(st, s->decl.type));

             else

                 t = s->decl.type;

+            n->expr.isconst = s->decl.isconst;

             settype(st, n, t);

             n->expr.did = s->decl.did;

             if (s->decl.isgeneric && !st->ingeneric) {

@@ -1175,6 +1193,8 @@

     if (n->decl.init) {

         inferexpr(st, n->decl.init, NULL, NULL);

         unify(st, n, type(st, n), type(st, n->decl.init));

+        if (n->decl.isconst && !n->decl.init->expr.isconst)

+            fatal(n->line, "non-const initializer for \"%s\"", ctxstr(st, n));

     } else {

         if (n->decl.isconst && !n->decl.isextern)

             fatal(n->line, "non-extern \"%s\" has no initializer", ctxstr(st, n));