[UBSan] Add returns-nonnull sanitizer.

Summary:
This patch adds a runtime check verifying that functions
annotated with "returns_nonnull" attribute do in fact return nonnull pointers.
It is based on suggestion by Jakub Jelinek:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140623/223693.html.

Test Plan: regression test suite

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D4849

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@215485 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 13 insertions, 0 deletions

diff --git a/test/ubsan/TestCases/Misc/nonnull.cpp b/test/ubsan/TestCases/Misc/nonnull.cpp
new file mode 100644
index 000000000..8b5fcaf43
--- /dev/null
+++ b/test/ubsan/TestCases/Misc/nonnull.cpp
@@ -0,0 +1,13 @@
+// RUN: %clangxx -fsanitize=returns-nonnull-attribute %s -O3 -o %t
+// RUN: %run %t foo
+// RUN: %run %t 2>&1 | FileCheck %s
+
+__attribute__((returns_nonnull))
+char *foo(char *a) {
+  return a;
+  // CHECK: nonnull.cpp:[[@LINE+1]]:1: runtime error: null pointer returned from function declared to never return null
+}
+
+int main(int argc, char **argv) {
+  return foo(argv[1]) == 0;
+}