util/romcc: Fix parsing of empty string literal

The corner case of an empty string literal was causing romcc to
segfault. This checks if the literal is empty, and if so allocates a
size one buffer for the terminating null character. A test case for
this is added to ensure it doesn't happen again.

Found-by: Coverity CID 1129099
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Change-Id: I067160a3b9998184f44e4878ef6269f372fe68bb
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32852
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/util/romcc/tests/simple_test87.c b/util/romcc/tests/simple_test87.c
new file mode 100644
index 0000000000..6a1148c46a
--- /dev/null
+++ b/util/romcc/tests/simple_test87.c
@@ -0,0 +1,4 @@
+static void main(void)
+{
+	char *x = "";
+}