[libc++][hardening] Don't trigger uncategorized assertions in the hardened mode.

[var-const]

Summary

The hardened mode is intended to only include security-critical,
relatively low-overhead checks that are intended to be usable in
production. By default, assertions are excluded from this mode.

[var-const]

Run the tests intended for debug mode in hardened mode, but x-fail them.

[Mordante]

libcxx/include/__config

287

I noticed there are quite a number of cheap tests in this category. For example nullptr guards in std::string. Would it make sense to put them in a "cheap-to-test-category". Maybe a _LIBCPP_ASSERT_PRECONDITION?

[ldionne]

LGTM w/ UNSUPPORTED and green CI! Thanks!

libcxx/include/__config

287

I suggest we discuss this in D155873.

libcxx/test/libcxx/algorithms/alg.sorting/assert.min.max.pass.cpp

13 ↗

(On Diff #542587)

As a follow-up patch, I think we could do this:

# This,
AddFeature("libcpp-has-hardened-mode")             if hardening_mode == "hardened" else None,
AddFeature("libcpp-has-debug-mode")                if hardening_mode == "debug" else None,
AddFeature("libcpp-has-unchecked-mode")            if hardening_mode == "unchecked" else None,

# Or that
AddFeature(f"libcpp-hardening-mode={hardening_mode}")

And then we could switch to // UNSUPPORTED: libcpp-has-unchecked-mode (or the other syntax). This would be a bit easier to understand.

15 ↗

(On Diff #542587)

In this patch, I would use UNSUPPORTED here. Using XFAIL is really nice in theory because it will notify us if we forget to un-XFAIL a test after adding an assertion to the hardened mode, but unfortunately the test is UB when it's run outside of the debug mode. So in practice I think the only thing we can use consistently is UNSUPPORTED. For example you mentioned one of the barrier tests timing out.

[var-const]

Address feedback and fix the CI.

[var-const]

libcxx/include/__config

287

@Mordante I think it would be easier to discuss in the other patch like @ldionne suggested above because it deals with some of those assertions (including the nullptr guards in string).

libcxx/test/libcxx/algorithms/alg.sorting/assert.min.max.pass.cpp

13 ↗

(On Diff #542587)

https://reviews.llvm.org/D155906

[Mordante]

libcxx/include/__config

287

That's fine by me.

libcxx/include/__config

 // Hardened mode checks.
 
 // clang-format off
 #  if _LIBCPP_ENABLE_HARDENED_MODE
 
 // Enabled checks.
 #    define _LIBCPP_ASSERT_VALID_INPUT_RANGE(expression, message)      _LIBCPP_ASSERT(expression, message)
 #    define _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(expression, message)   _LIBCPP_ASSERT(expression, message)
-// TODO(hardening): Don't enable uncategorized assertions in the hardened mode.
-#    define _LIBCPP_ASSERT_UNCATEGORIZED(expression, message)          _LIBCPP_ASSERT(expression, message)
 // Disabled checks.
 #    define _LIBCPP_ASSERT_COMPATIBLE_ALLOCATOR(expression, message)   _LIBCPP_ASSUME(expression)
 #    define _LIBCPP_ASSERT_INTERNAL(expression, message)               _LIBCPP_ASSUME(expression)
+#    define _LIBCPP_ASSERT_UNCATEGORIZED(expression, message)          _LIBCPP_ASSUME(expression)
 
 // Debug mode checks.
 
 #  elif _LIBCPP_ENABLE_DEBUG_MODE
 
 // All checks enabled.
 #    define _LIBCPP_ASSERT_VALID_INPUT_RANGE(expression, message)       _LIBCPP_ASSERT(expression, message)
 #    define _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(expression, message)    _LIBCPP_ASSERT(expression, message)