From bc5322a9c6a12d020a45ee8051349521fa05fbd6 Mon Sep 17 00:00:00 2001
From: Alastair Fyfe <csvaf@ucbvax.Berkeley.EDU>
Date: Thu, 19 May 1983 01:30:12 -0800
Subject: [PATCH] language specific functions to build and evaluate array
 reference trees

SCCS-vsn: old/dbx/c.c 1.3
---
 usr/src/old/dbx/c.c | 80 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 79 insertions(+), 1 deletion(-)

diff --git a/usr/src/old/dbx/c.c b/usr/src/old/dbx/c.c
index daaf5a9c99..60e371a6e7 100644
--- a/usr/src/old/dbx/c.c
+++ b/usr/src/old/dbx/c.c
@@ -1,6 +1,6 @@
 /* Copyright (c) 1982 Regents of the University of California */
 
-static char sccsid[] = "@(#)c.c 1.2 %G%";
+static char sccsid[] = "@(#)c.c 1.3 %G%";
 
 /*
  * C-dependent symbol routines.
@@ -37,6 +37,8 @@ public c_init()
     language_setop(lang, L_PRINTDECL, c_printdecl);
     language_setop(lang, L_PRINTVAL, c_printval);
     language_setop(lang, L_TYPEMATCH, c_typematch);
+    language_setop(lang, L_BUILDAREF, c_buildaref);
+    language_setop(lang, L_EVALAREF, c_evalaref);
 }
 
 /*
@@ -665,3 +667,79 @@ Symbol s;
     }
     return str;
 }
+public Node c_buildaref(a, slist)
+Node a, slist;
+{
+    register Symbol t;
+    register Node p;
+    Symbol etype, atype, eltype;
+    Node esub, r;
+
+    r = a;
+    t = rtype(a->nodetype);
+    eltype = t->type;
+    if (t->class == PTR) {
+	p = slist->value.arg[0];
+	if (not compatible(p->nodetype, t_int)) {
+	    beginerrmsg();
+	    fprintf(stderr, "bad type for subscript of ");
+	    prtree(stderr, a);
+	    enderrmsg();
+	}
+	r = build(O_MUL, p, build(O_LCON, (long) size(eltype)));
+	r = build(O_ADD, build(O_RVAL, a), r);
+	r->nodetype = eltype;
+    } else if (t->class != ARRAY) {
+	beginerrmsg();
+	prtree(stderr, a);
+	fprintf(stderr, " is not an array");
+	enderrmsg();
+    } else {
+	p = slist;
+	t = t->chain;
+	for (; p != nil and t != nil; p = p->value.arg[1], t = t->chain) {
+	    esub = p->value.arg[0];
+	    etype = rtype(esub->nodetype);
+	    atype = rtype(t);
+	    if (not compatible(atype, etype)) {
+		beginerrmsg();
+		fprintf(stderr, "subscript ");
+		prtree(stderr, esub);
+		fprintf(stderr, " is the wrong type");
+		enderrmsg();
+	    }
+	    r = build(O_INDEX, r, esub);
+	    r->nodetype = eltype;
+	}
+	if (p != nil or t != nil) {
+	    beginerrmsg();
+	    if (p != nil) {
+		fprintf(stderr, "too many subscripts for ");
+	    } else {
+		fprintf(stderr, "not enough subscripts for ");
+	    }
+	    prtree(stderr, a);
+	    enderrmsg();
+	}
+    }
+    return r;
+}
+
+/*
+ * Evaluate a subscript index.
+ */
+
+public int c_evalaref(s, i)
+Symbol s;
+long i;
+{
+    long lb, ub;
+
+    s = rtype(s)->chain;
+    lb = s->symvalue.rangev.lower;
+    ub = s->symvalue.rangev.upper;
+    if (i < lb or i > ub) {
+	error("subscript out of range");
+    }
+    return (i - lb);
+}
-- 
2.20.1