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https://issues.apache.org/jira/browse/THRIFT-5355?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jens Geyer resolved THRIFT-5355.
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Fix Version/s: 0.15.0
Assignee: Jens Geyer
Resolution: Fixed
> Do not rely on compiler and check boundaries
> --------------------------------------------
>
> Key: THRIFT-5355
> URL: https://issues.apache.org/jira/browse/THRIFT-5355
> Project: Thrift
> Issue Type: Improvement
> Components: C++ - Library
> Reporter: Jens Geyer
> Assignee: Jens Geyer
> Priority: Major
> Fix For: 0.15.0
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> C++ considers the overflow of a signed integer to be an undefined behavior
> (even with the "Signed Integers are Two's Complement" update:
> [http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0907r1.html] ).
> Instead of relying on tests(1) to discover if a compiler does not handle the
> signed integer overflow as we expect it to, we should add an explicit check
> before incrementing.
> (1) See
> [thrift/lib/cpp/src/thrift/async/TConcurrentClientSyncInfo.cpp|https://github.com/apache/thrift/blob/c4e899a6d64aa97430ec9f7608d38db2095f6159/lib/cpp/src/thrift/async/TConcurrentClientSyncInfo.cpp#L33-L34]
> Lines 33 to 34 in
> [c4e899a|https://github.com/apache/thrift/commit/c4e899a6d64aa97430ec9f7608d38db2095f6159]
> | |// test rollover all the time|
> | |nextseqid_((std::numeric_limits<int32_t>::max)()-10),|
>
> Quick check on [https://godbolt.org/z/d7W8ds] shows that Clang is able to
> optimize and just do the +1 so modern compilers should be able to keep the
> same performances where hardware permits.
> In addition, some company rules might require code to do just that:
> [https://wiki.sei.cmu.edu/confluence/display/c/INT32-C.+Ensure+that+operations+on+signed+integers+do+not+result+in+overflow]
>
>
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