[PATCH 3/3] ir-validate: validate return value

[Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>]

A valid non-void function should not return VOID.
VOID can only be returned if no return statements
have been issued.

Note: even if the expression is erroneous, and thus VOID,
      this returned value would be via a phi-node.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
 ir.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/ir.c b/ir.c
index 836d4eb24..2e284c251 100644
--- a/ir.c
+++ b/ir.c
@@ -107,6 +107,17 @@ static int check_switch(struct entrypoint *ep, struct instruction *insn)
 	return err;
 }
 
+static int check_return(struct instruction *insn)
+{
+	struct symbol *ctype = insn->type;
+
+	if (ctype && ctype->bit_size > 0 && insn->src == VOID) {
+		sparse_error(insn->pos, "return without value");
+		return 1;
+	}
+	return 0;
+}
+
 static int validate_insn(struct entrypoint *ep, struct instruction *insn)
 {
 	int err = 0;
@@ -152,6 +163,10 @@ static int validate_insn(struct entrypoint *ep, struct instruction *insn)
 		err += check_user(insn, insn->src);
 		break;
 
+	case OP_RET:
+		err += check_return(insn);
+		break;
+
 	case OP_BR:
 		err += check_branch(ep, insn, insn->bb_true);
 		break;
-- 
2.18.0