[libcxx-commits] [libcxx] [ASan][libc++] Annotating `std::basic_string` with all allocators (PR #75845)

[via libcxx-commits]

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@@ -0,0 +1,54 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: asan
+// UNSUPPORTED: c++03
+
+// Basic test if ASan annotations work for basic_string.
+
+#include <string>
+#include <cassert>
+#include <cstdlib>
+
+#include "asan_testing.h"
+#include "min_allocator.h"
+#include "test_iterators.h"
+#include "test_macros.h"
+
+extern "C" void __sanitizer_set_death_callback(void (*callback)(void));
+
+void do_exit() { exit(0); }
+
+int main(int, char**) {
+  {
+    typedef cpp17_input_iterator<char*> MyInputIter;
+    // Should not trigger ASan.
+    std::basic_string<char, std::char_traits<char>, safe_allocator<char>> v;
+    char i[] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'a', 'b', 'c', 'd', 'e',
+                'f', 'g', 'h', 'i', 'j', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'};
+
+    v.insert(v.begin(), MyInputIter(i), MyInputIter(i + 29));
+    assert(v[0] == 'a');
+    assert(is_string_asan_correct(v));
+  }
+
+  __sanitizer_set_death_callback(do_exit);
+  {
+    using T     = char;
+    using C     = std::basic_string<T, std::char_traits<T>, safe_allocator<T>>;
+    const T t[] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'a', 'b', 'c', 'd', 'e',
+                   'f', 'g', 'h', 'i', 'j', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'};
+    C c(std::begin(t), std::end(t));
+    assert(is_string_asan_correct(c));
+    assert(__sanitizer_verify_contiguous_container(c.data(), c.data() + c.size() + 1, c.data() + c.capacity() + 1) !=
+           0);
+    volatile T foo = c[c.size() + 1]; // should trigger ASAN. Use volatile to prevent being optimized away.
----------------
EricWF wrote:

`volatile` on `T foo`  won't prevent the compiler from optimizing away the read from `std::string`. If the compiler can constant fold `foo`'s initializer, it doesn't have to perform the ASAN triggering memory access.

https://github.com/llvm/llvm-project/pull/75845