[PATCH] D77150: [Analyzer] New Option for ContainerModeling: AggressiveEraseModeling

[Balogh, Ádám via Phabricator via cfe-commits]

baloghadamsoftware created this revision.
baloghadamsoftware added reviewers: NoQ, Szelethus.
baloghadamsoftware added a project: clang.
Herald added subscribers: ASDenysPetrov, martong, steakhal, Charusso, gamesh411, dkrupp, donat.nagy, mikhail.ramalho, a.sidorin, rnkovacs, szepet, xazax.hun, whisperity.

A typical (bad) algorithm for erasing elements of a list is the following:

  for(auto i = L.begin(); i != L.end(); ++i) {
     if (condition(*i))
       i = L.erase(i);
  }

If `condition()` returns true for the last element, then `erase()` returns the past-the-end iterator which the loop tries to increment which leads to undefined behavior. However, the iterator range checker does not find this bug because the "loop iteration before that last iteration" cannot be recognized by the analyzer. Instead we added an option in this patch to `ContainerModeling` which enables the modeling checker to assume after every erase that the result is the past-the-end iterator (if this case is possible).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77150

Files:
  clang/include/clang/StaticAnalyzer/Checkers/Checkers.td
  clang/lib/StaticAnalyzer/Checkers/ContainerModeling.cpp
  clang/test/Analysis/analyzer-config.c

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