ref: c25c5f047c289b9e5d0d07e73d80244ceb97786e
parent: 76bddee887ffd0d602cbbf5fc8e95869249943c5
author: Roberto E. Vargas Caballero <[email protected]>
date: Mon Sep 26 07:41:01 EDT 2016
[cc2-qbe] Implement switch statements This is a first implementation of switches, which uses a if-else-if chain. At this point we cannot implement any other form of switch because we need support for indirect jump in qbe.
--- a/cc2/arch/qbe/cgen.c
+++ b/cc2/arch/qbe/cgen.c
@@ -414,6 +414,47 @@
return NULL;
}
+static void
+swtch_if(Node *idx)
+{+ Node aux1, aux2, *np;
+ Symbol *deflabel = NULL;
+
+ for (;;) {+ np = delstmt();
+ setlabel(np->label);
+
+ switch (np->op) {+ case OESWITCH:
+ if (deflabel) {+ aux1.op = OJMP;
+ aux1.label = NULL;
+ aux1.u.sym = deflabel;
+ cgen(&aux1);
+ }
+ return;
+ case OCASE:
+ aux1 = *np;
+ aux1.op = OBRANCH;
+ aux1.label = NULL;
+ aux1.left = &aux2;
+
+ aux2.op = OEQ;
+ aux2.type = idx->type;
+ aux2.left = np->left;
+ aux2.right = idx;
+
+ cgen(&aux1);
+ break;
+ case ODEFAULT:
+ deflabel = np->u.sym;
+ break;
+ default:
+ abort();
+ }
+ }
+}
+
static Node *
rhs(Node *np, Node *ret)
{@@ -550,11 +591,6 @@
return lhs(l, ret);
case OFIELD:
return field(np, ret, 0);
- case OCASE:
- case ODEFAULT:
- case OESWITCH:
- case OBSWITCH:
- /* TODO: implement these operators */
default:
abort();
}
@@ -585,6 +621,10 @@
case ORET:
p = (np->left) ? rhs(np->left, &ret) : NULL;
code(ASRET, NULL, p, NULL);
+ break;
+ case OBSWITCH:
+ p = rhs(np->left, &ret);
+ swtch_if(p);
break;
default:
rhs(np, &ret);