From 245bf2db0e274757ccdacef3834ebf9aa1aac087 Mon Sep 17 00:00:00 2001
From: Michael Beck <beck@ipd.info.uni-karlsruhe.de>
Date: Mon, 2 Jun 2008 10:32:32 +0000
Subject: [PATCH] add checks for missing return statement

[r19916]
---
 parser.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/parser.c b/parser.c
index 198ca6b..531d07f 100644
--- a/parser.c
+++ b/parser.c
@@ -4314,6 +4314,64 @@ static void check_declarations(void)
 	}
 }
 
+/**
+ * check all returns vor matching type.
+ */
+static bool search_return_statements(statement_t *statement) {
+	switch(statement->kind) {
+	case STATEMENT_RETURN:
+		/* ok, found a return */
+		return true;
+	case STATEMENT_IF: {
+		/* return must be found on then and else */
+		if_statement_t *if_stat = &statement->ifs;
+		if(if_stat->true_statement != NULL && if_stat->false_statement != NULL) {
+			return search_return_statements(if_stat->true_statement) &&
+			       search_return_statements(if_stat->false_statement);
+		}
+		break;
+	}
+	case STATEMENT_DO_WHILE: {
+		do_while_statement_t *do_stmt = &statement->do_while;
+		if(do_stmt->body != NULL) {
+			if (search_return_statements(do_stmt->body))
+				return true;
+		}
+		break;
+	}
+	case STATEMENT_COMPOUND: {
+		/* search the last statement */
+		compound_statement_t *compound = &statement->compound;
+		statement_t *statement = compound->statements;
+		if(statement == NULL)
+			return false;
+		for( ; statement != NULL; statement = statement->base.next) {
+			if (search_return_statements(statement))
+				return true;
+		}
+		break;
+	}
+	default:
+		break;
+	}
+	return false;
+}
+
+/**
+ * Check returns of a function.
+ */
+static void check_return_type(declaration_t *declaration) {
+	function_type_t *function_type = &declaration->type->function;
+	type_t          *ret_type      = function_type->return_type;
+
+	if (ret_type != type_void) {
+		if (! search_return_statements(declaration->init.statement)) {
+			warningf(HERE, "missing return statement at end of non-void function '%Y'",
+					declaration->symbol);
+		}
+	}
+}
+
 static void parse_external_declaration(void)
 {
 	/* function-definitions and declarations both start with declaration
@@ -4425,6 +4483,7 @@ static void parse_external_declaration(void)
 		assert(current_function == declaration);
 		current_function = old_current_function;
 		label_pop_to(label_stack_top);
+		check_return_type(declaration);
 	}
 
 end_of_parse_external_declaration:
-- 
2.20.1