test: add test for segfaulting CI script

The C code leaked out of src/, so I moved .clang-format and some compile
options to the root directory.

Also, I'm starting to hit test execution limits; I'm going to limit the
repositories used for stress testing.

4 files changed, 42 insertions, 0 deletions

diff --git a/test/sigsegv/CMakeLists.txt b/test/sigsegv/CMakeLists.txt
new file mode 100644
index 0000000..b92147d
--- /dev/null
+++ b/test/sigsegv/CMakeLists.txt
@@ -0,0 +1,11 @@
+# Hopefully putting the NULL reference to a separate library should force the
+# sigsegv binary to crash. If I put it in main.c, surprisingly, Clang (with
+# -O2) produces a binary that doesn't crash: https://godbolt.org/z/joeqEEs3Y.
+# To force it to crash, the -fno-delete-null-pointer-checks flag is required:
+# https://godbolt.org/z/o3xEoeG3z. This is a bit hacky though; putting the
+# reference in a separate library should also do the trick.
+
+add_library(null lib.c)
+
+add_executable(sigsegv main.c)
+target_link_libraries(sigsegv PRIVATE null)
diff --git a/test/sigsegv/lib.c b/test/sigsegv/lib.c
new file mode 100644
index 0000000..1e136cc
--- /dev/null
+++ b/test/sigsegv/lib.c
@@ -0,0 +1,5 @@
+#include "lib.h"
+
+#include <stddef.h>
+
+struct data *data = NULL;
diff --git a/test/sigsegv/lib.h b/test/sigsegv/lib.h
new file mode 100644
index 0000000..1f162d5
--- /dev/null
+++ b/test/sigsegv/lib.h
@@ -0,0 +1,10 @@
+#ifndef __LIB_H__
+#define __LIB_H__
+
+struct data {
+	int x;
+};
+
+extern struct data *data;
+
+#endif
diff --git a/test/sigsegv/main.c b/test/sigsegv/main.c
new file mode 100644
index 0000000..428d168
--- /dev/null
+++ b/test/sigsegv/main.c
@@ -0,0 +1,16 @@
+#include "lib.h"
+
+#include <stdio.h>
+
+int main(void)
+{
+	puts("Started the test program.");
+	fflush(stdout);
+
+	printf("This will crash: %d.\n", data->x);
+
+	puts("You shouldn't see this.");
+	fflush(stdout);
+
+	return 0;
+}