Add runtime tests for null ptr arithmetic (checkedc#378)

Author: Mandeep Singh Grang

tests/dynamic_checking/null_ptr_checks/ptr-arith-fail.c

@@ -0,0 +1,114 @@
+// Test arithmetic on null pointers.
+//
+// RUN: %clang %s -o %t1 %checkedc_target_flags
+
+// RUN: %checkedc_rununder %t1 1 -DARR | FileCheck %s --check-prefix FAIL1
+// RUN: %checkedc_rununder %t1 2 -DARR | FileCheck %s --check-prefix FAIL2
+// RUN: %checkedc_rununder %t1 3 -DARR | FileCheck %s --check-prefix FAIL3
+
+// RUN: %checkedc_rununder %t1 1 | FileCheck %s --check-prefix FAIL1
+// RUN: %checkedc_rununder %t1 2 | FileCheck %s --check-prefix FAIL2
+// RUN: %checkedc_rununder %t1 3 | FileCheck %s --check-prefix FAIL3
+
+// RUN: %checkedc_rununder %t1 100 -DARR | FileCheck %s --check-prefix PASS1
+// RUN: %checkedc_rununder %t1 100 | FileCheck %s --check-prefix PASS1
+
+#include <assert.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdchecked.h>
+
+array_ptr<char> arr_p : count(3) = NULL;
+nt_array_ptr<char> nt_arr_p : count(3) = NULL;
+
+array_ptr<char> arr_s : count(3) = "abc";
+int *t = NULL;
+
+void handle_error(int err) {
+  puts("Error: null pointer arithmetic");
+  _Exit(0);
+}
+
+void fail1() {
+  // FAIL1: Error: null pointer arithmetic
+#ifdef ARR
+  arr_p++;
+#else
+  nt_arr_p++;
+#endif
+}
+
+void fail2() {
+  // FAIL2: Error: null pointer arithmetic
+#ifdef ARR
+  arr_p[1]--;
+#else
+  nt_arr_p[1]--;
+#endif
+}
+
+void f1(array_ptr<char> a) {}
+void f2(nt_array_ptr<char> a) {}
+
+void fail3() {
+  // FAIL3: Error: null pointer arithmetic
+#ifdef ARR
+  f1(--arr_p);
+#else
+  f2(--nt_arr_p);
+#endif
+}
+
+void pass1() {
+  // PASS1: PASS
+#ifdef ARR
+  arr_s++;
+#else
+  t++;
+#endif
+  puts("PASS");
+}
+
+int main(int argc, array_ptr<char*> argv : count(argc)) {
+  signal(SIGILL, handle_error);
+
+  // This makes sure output is not buffered for when
+  // we hit errors.
+  int err = setvbuf(stdout, NULL, _IONBF, 0);
+  if (err) {
+    // CHECK-NOT: Error Setting Up Buffering
+    puts("Error Setting Up Buffering");
+    return EXIT_FAILURE;
+  }
+
+  if (argc < 2) {
+    // CHECK-NOT: Requires Argument
+    puts("Requires Argument");
+    return EXIT_FAILURE;
+  }
+
+  int testcase = atoi(argv[1]);
+  switch (testcase) {
+    case 1:
+      fail1();
+      break;
+    case 2:
+      fail2();
+      break;
+    case 3:
+      fail3();
+      break;
+
+    case 100:
+      pass1();
+      break;
+
+    default:
+      // CHECK-NOT: Unexpected test case
+      puts("Unexpected test case");
+      return EXIT_FAILURE;
+  }
+  return EXIT_SUCCESS;
+}