[sanitizer] enable random shuffling the memory chunks inside the allocator, under a flag. Set this flag for the scudo allocator, add a test.
llvm-svn: 279793
diff --git a/compiler-rt/test/scudo/random_shuffle.cpp b/compiler-rt/test/scudo/random_shuffle.cpp
new file mode 100644
index 0000000..54768a5
--- /dev/null
+++ b/compiler-rt/test/scudo/random_shuffle.cpp
@@ -0,0 +1,23 @@
+// RUN: %clang_scudo %s -o %t
+// RUN: rm -rf %T/random_shuffle_tmp_dir
+// RUN: mkdir %T/random_shuffle_tmp_dir
+// RUN: %run %t 100 > %T/random_shuffle_tmp_dir/out1
+// RUN: %run %t 100 > %T/random_shuffle_tmp_dir/out2
+// RUN: %run %t 10000 > %T/random_shuffle_tmp_dir/out1
+// RUN: %run %t 10000 > %T/random_shuffle_tmp_dir/out2
+// RUN: not diff %T/random_shuffle_tmp_dir/out?
+// RUN: rm -rf %T/random_shuffle_tmp_dir
+
+// Tests that the allocator shuffles the chunks before returning to the user.
+
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+ int alloc_size = argc == 2 ? atoi(argv[1]) : 100;
+ char *base = new char[alloc_size];
+ for (int i = 0; i < 20; i++) {
+ char *p = new char[alloc_size];
+ printf("%zd\n", base - p);
+ }
+}