[compiler-rt][UBSan] Sanitization for alignment assumptions.

Summary:
This is the compiler-rt part.
The clang part is D54589.

Reviewers: filcab, vsk, #sanitizers, vitalybuka, rsmith, morehouse

Reviewed By: morehouse

Subscribers: rjmccall, krytarowski, rsmith, kcc, srhines, kubamracek, dberris, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D54590

llvm-svn: 351106

1 files changed, 27 insertions, 0 deletions

diff --git a/compiler-rt/test/fuzzer/AlignmentAssumptionTest.cpp b/compiler-rt/test/fuzzer/AlignmentAssumptionTest.cpp
new file mode 100644
index 00000000000..c100928fecd
--- /dev/null
+++ b/compiler-rt/test/fuzzer/AlignmentAssumptionTest.cpp
@@ -0,0 +1,27 @@
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+
+// Test for alignment assumption failure.
+
+#include <assert.h>
+#include <climits>
+#include <cstddef>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+
+static volatile int32_t Sink;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  if (Size > 0 && Data[0] == 'H') {
+    Sink = 1;
+    if (Size > 1 && Data[1] == 'i') {
+      Sink = 2;
+      if (Size > 2 && Data[2] == '!') {
+        __builtin_assume_aligned(Data, 0x80000000);
+      }
+    }
+  }
+  return 0;
+}