[PATCH] D49112: [Sema] Implement -Wmemset-transposed-args

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington created this revision.
erik.pilkington added reviewers: rsmith, aaron.ballman, arphaman.
Herald added a subscriber: dexonsmith.

This warning tries to catch programs that incorrectly call memset with the second and third arguments transposed, ie `memset(ary, sizeof(ary), 0)` instead of `memset(ary, 0, sizeof(ary))`. This is done by looking at two factors: 1) if the last argument is `0`, then this is likely a bug (looks this is what GCC's implementation does) and 2) if the last argument isn't `0`, but the second argument is a `sizeof`expression. This catches cases like `memset(ary, sizeof(ary), 0xff)`. I also grouped a couple of related diagnostics that deal with these c functions into a new group, -Wsuspicious-memaccess.

llvm.org/PR36242

Thanks for taking a look!
Erik


Repository:
  rC Clang

https://reviews.llvm.org/D49112

Files:
  clang/include/clang/Basic/DiagnosticGroups.td
  clang/include/clang/Basic/DiagnosticSemaKinds.td
  clang/lib/Sema/SemaChecking.cpp
  clang/test/Sema/transpose-memset.c

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