[PATCH] D75851: [Analyzer][StreamChecker] Added evaluation of fseek.

[Balázs Kéri via Phabricator via cfe-commits]

balazske marked an inline comment as done.
balazske added a comment.

I do not like to make difference between error from `fseek` and error from any other function that may fail. `AnyError` can be used to handle every case. After a failed file operation we do not know if it was `feof` or `ferror` kind of error. `fseek` is only special because it can fail additionally without `feof` or `ferror`. If the kind of the last operation needs to be known later, it can be saved in the stream state.



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Comment at: clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp:382-384
+  C.addTransition(StateNotFailed);
+  C.addTransition(StateFailedWithFError);
+  C.addTransition(StateFailedWithoutFError);
----------------
Szelethus wrote:
> This seems a bit excessive, we could merge the last two into `FSeekError`.
There are 3 cases:
 - `fseek` did not fail at all. Return value is zero. This is `StateNotFailed`.
 - `fseek` failed but none of the error flags is true afterwards. Return value is nonzero but `feof` and `ferror` are not true. This is `StateFailedWithoutFError`.
 - `fseek` failed and we have `feof` or `ferror` set (never both). Return value is nonzero and `feof` or `ferror` will be true. This is `StateFailedWithFError`. And an use of `AnyError`, otherwise we need here 2 states, one for `feof` and one for `ferror`. But it is not important here if `feof` or `ferror` is actually true, so the special value `AnyError` is used and only one new state instead of two.


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https://reviews.llvm.org/D75851