Fixes PR#52245. I've also added a few test cases beyond PR#52245 that would also fail with the current implementation, which is quite brittle in many respects (e.g. it uses the `hasDescendant()` matcher to find the container that is being accessed, which is very easy to trick, as in the example in PR#52245).
I have not been able to reproduce the second issue mentioned in PR#52245 (namely that using the `data()` member function is suggested even for containers that don't have it), but I've added a test case for it to be sure.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D113863
This reverts commit 626586fc25.
Tweak the test for Windows. Windows defaults to delayed template
parsing, which resulted in the main template definition not registering
the test on Windows. Process the file with the additional
`-fno-delayed-template-parsing` flag to change the default beahviour.
Additionally, add an extra check for the fix it and use a more robust
test to ensure that the value is always evaluated.
Differential Revision: https://reviews.llvm.org/D108893
This reverts commit 76dc8ac36d.
Restore the change. The test had an incorrect negative from testing.
The test is expected to trigger a failure as mentioned in the review
comments. This corrects the test and should resolve the failure.
This introduces a new check, readability-containter-data-pointer. This
check is meant to catch the cases where the user may be trying to
materialize the data pointer by taking the address of the 0-th member of
a container. With C++11 or newer, the `data` member should be used for
this. This provides the following benefits:
- `.data()` is easier to read than `&[0]`
- it avoids an unnecessary re-materialization of the pointer
* this doesn't matter in the case of optimized code, but in the case
of unoptimized code, this will be visible
- it avoids a potential invalid memory de-reference caused by the
indexing when the container is empty (in debug mode, clang will
normally optimize away the re-materialization in optimized builds).
The small potential behavioural change raises the question of where the
check should belong. A reasoning of defense in depth applies here, and
this does an unchecked conversion, with the assumption that users can
use the static analyzer to catch cases where we can statically identify
an invalid memory de-reference. For the cases where the static analysis
is unable to prove the size of the container, UBSan can be used to track
the invalid access.
Special thanks to Aaron Ballmann for the discussion on whether this
check would be useful and where to place it.
This also partially resolves PR26817!
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D108893
Danny Mösch