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https://issues.apache.org/jira/browse/IMPALA-5031?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16650905#comment-16650905
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ASF subversion and git services commented on IMPALA-5031:
---------------------------------------------------------
Commit 8fc702be0c5017775e99fba0e88772ce3c14eb68 in impala's branch
refs/heads/master from [~jbapple]
[ https://git-wip-us.apache.org/repos/asf?p=impala.git;h=8fc702b ]
IMPALA-5031: fix signed overflows in decimal
The standard says that overflow for signed arithmetic operations is
undefined behavior; see [expr]:
If during the evaluation of an expression, the result is not
mathematically defined or not in the range of representable values
for its type, the behavior is undefined.
and [basic.fundamental]:
Unsigned integers shall obey the laws of arithmetic modulo 2^n
where n is the number of bits in the value representation of that
particular size of integer. This implies that unsigned arithmetic
does not overflow because a result that cannot be represented by
the resulting unsigned integer type is reduced modulo the number
that is one greater than the largest value that can be represented
by the resulting unsigned integer type.
All of the overflows fixed in this patch were tested with expr-test's
DecimalArithmeticTest.
Change-Id: Ibf882428931e4f4264be2fc8cd9d6b1fc89b8ace
Reviewed-on: http://gerrit.cloudera.org:8080/11604
Reviewed-by: Jim Apple <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>
> UBSAN clean and method for testing UBSAN cleanliness
> ----------------------------------------------------
>
> Key: IMPALA-5031
> URL: https://issues.apache.org/jira/browse/IMPALA-5031
> Project: IMPALA
> Issue Type: Task
> Components: Backend, Infrastructure
> Affects Versions: Impala 2.9.0
> Reporter: Jim Apple
> Assignee: Jim Apple
> Priority: Minor
>
> http://releases.llvm.org/3.8.0/tools/clang/docs/UndefinedBehaviorSanitizer.html
> builds are supported after https://gerrit.cloudera.org/#/c/6186/, but
> Impala's test suite triggers many errors under UBSAN. Those errors should be
> fixed and then there should be a way to run the test suite under UBSAN and
> fail if there were any errors detected.
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