[PATCH] D137379: [-Wunsafe-buffer-usage] Add warnings for unsafe buffer accesses by array subscript operations

[Ziqing Luo via Phabricator via cfe-commits]

ziqingluo-90 added a comment.

In D137379#4225000 <https://reviews.llvm.org/D137379#4225000>, @manojgupta wrote:

> This is firing even in checked length codes, is that expected?

Yes, it is expected.  The unsafe buffer analysis is syntax-based.  The analysis warns operations that do not follow the buffer-safe programming model we are suggesting.  The programming model prohibits pointer arithmetic.  In the model, pointer arithmetic and buffer access can be done using hardened libc++ facilities such as `std::span`.

More information about the analysis and the programming model can be found at https://discourse.llvm.org/t/rfc-c-buffer-hardening/65734.

To suppress the warning, you can either turn the analysis off using `-Wno-unsafe-buffer-usage` or put code in a pair of opt-out pragmas `#pragma clang unsafe_buffer_usage begin` & `#pragma clang unsafe_buffer_usage end`


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https://reviews.llvm.org/D137379