<string> Add asan annotations

[Michael Schellenberger Costa (miscco)]

This is a mirror of #2071

[Charlie Barto (barcharcraz)]

this could be a static_cast I think.

[Michael Schellenberger Costa (miscco)]

I would also prefer to use reinterpret_cast here, we need to deal with different character types

[Charlie Barto (barcharcraz)]

This particular cast does not though

[Stephan T. Lavavej (StephanTLavavej)]

I've pushed a conflict-free merge with main, followed by a preprocessor fix and a comment cleanup.

[Curtis J Bezault (cbezault)]

Educational comment: /D_ANNOTATE_VECTOR is needed in src/vctools/crt/asan/mt/libasan.nativeproj because the ASan runtime internally uses vector. As long as the ASan runtime doesn't use string internally /D_ANNOTATE_STRING is not strictly needed but won't hurt.

[Stephan T. Lavavej (StephanTLavavej)]

Ah, excellent! IIRC, ASAN is removing (or has removed) the vector dependency.

[Stephan T. Lavavej (StephanTLavavej)]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[Stephan T. Lavavej (StephanTLavavej)]

I've pushed a commit to fix an internal test run failure ("unresolved external symbol") by copying this pattern:

STL/tests/std/tests/GH_002030_asan_annotate_vector/test.cpp

Lines 25 to 30 in 313aa59

	#ifdef __SANITIZE_ADDRESS__
	extern "C" {
	void* __sanitizer_contiguous_container_find_bad_address(const void* beg, const void* mid, const void* end) noexcept;
	void __asan_describe_address(void*) noexcept;
	}
	#endif // ASan instrumentation enabled

STL/tests/std/tests/GH_002030_asan_annotate_vector/test.cpp

Lines 148 to 185 in 313aa59

	template <class T, class Alloc>
	bool verify_vector(vector<T, Alloc>& vec) {
	#ifdef __SANITIZE_ADDRESS__
	size_t buffer_bytes = vec.capacity() * sizeof(T);
	void* buffer = vec.data();
	void* aligned_start = align(8, 1, buffer, buffer_bytes);
	if (!aligned_start) {
	return true;
	}
	void* mid = vec.data() + vec.size();
	mid = mid > aligned_start ? mid : aligned_start;
	void* bad_address =
	__sanitizer_contiguous_container_find_bad_address(aligned_start, mid, vec.data() + vec.capacity());
	if (bad_address == nullptr) {
	return true;
	}
	if (bad_address < mid) {
	cout << bad_address << " was marked as poisoned when it should not be." << endl;
	} else {
	cout << bad_address << " was not marked as poisoned when it should be." << endl;
	}
	cout << "Vector State:" << endl;
	cout << " begin: " << buffer << endl;
	cout << " aligned begin: " << aligned_start << endl;
	cout << " last: " << reinterpret_cast<void*>(vec.data() + vec.size()) << endl;
	cout << " end: " << reinterpret_cast<void*>(vec.data() + vec.capacity()) << endl;
	__asan_describe_address(bad_address);
	return false;
	#else // ^^^ ASan instrumentation enabled ^^^ // vvv ASan instrumentation disabled vvv
	(void) vec;
	return true;
	#endif // Asan instrumentation disabled
	}

[Stephan T. Lavavej (StephanTLavavej)]

I've pushed an additional commit to fix ARM64EC and CHPE build breaks. I applied the fix to <vector> too.

[Stephan T. Lavavej (StephanTLavavej)]

Thanks for implementing this major feature and completing this part of the ASAN story!

😻 🚀 🎉

[Laurențiu Leahu-Vlăducu (doomlaur)]

Thanks for this amazing feature! 😄 Maybe you are aware of this already, but this feature unfortunately causes issues, as explained here (but also in 64-bit builds): https://developercommunity.visualstudio.com/t/VS2022---Address-sanitizer-on-x86-Debug-/10116361

I'm looking forward to using it as soon as strings work with ASAN again! 😃