c++ - 当 UBSAN (-fsanitize=undefined) 发现未定义行为时触发测试失败

Question

我在这里有一个小的单元测试，它具有未定义的行为。
源代码:

#include <gtest/gtest.h>

TEST(test, test)
{
    int k = 0x7fffffff;
    k += 1; // cause integer overflow
}

GTEST_API_ int main(int argc, char** argv)
{
    testing::InitGoogleTest(&argc, argv);
    return RUN_ALL_TESTS();
}

我在 CMakeLists.txt 中启用了 UBSAN:

cmake_minimum_required (VERSION 3.12)
project(ub CXX)

find_package(GTest REQUIRED)

add_executable        (ub_test ub_test.cpp)
target_link_libraries (ub_test GTest::GTest)
target_compile_options(ub_test PRIVATE -fsanitize=undefined)
target_link_options   (ub_test PRIVATE -fsanitize=undefined)

UBSAN 正确识别未定义的行为:

/home/steve/src/ub/ub_test.cpp:6:7: runtime error: signed integer overflow:
2147483647 + 1 cannot be represented in type 'int'

但是，我的测试仍然通过。

[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from test
[ RUN      ] test.test
/home/steve/src/ub/ub_test.cpp:6:7: runtime error: signed integer overflow:
2147483647 + 1 cannot be represented in type 'int'
[       OK ] test.test (0 ms)
[----------] 1 test from test (0 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (0 ms total)
[  PASSED  ] 1 test.

当 UBSAN 发现问题时，是否有可能触发测试失败(抛出异常、退出 1 等)？

Answer 1

根据documentation :

• -fsanitize=...: print a verbose error report and continue execution (default);

• -fno-sanitize-recover=...: print a verbose error report and exit the program;

• -fsanitize-trap=...: execute a trap instruction (doesn’t require UBSan run-time support).

Note that the trap / recover options do not enable the corresponding sanitizer, and in general need to be accompanied by a suitable -fsanitize= flag.

好像当你使用 -fsanitize= 时你所说的完全相同的事情发生了。它注意到未定义的行为并报告它，但继续执行。所以附加一个 -fno-sanitize-recover=all应该退出程序。