Commit Graph

6 Commits

Author SHA1 Message Date
Richard Trieu 71d74d4b25 Fix false positive in -Wunsequenced and templates.
For builtin logical operators, there is a well-defined ordering of argument
evaluation.  For overloaded operator of the same type, there is no argument
evaluation order, similar to other function calls.  When both are present,
uninstantiated templates with an operator&& is treated as an unresolved
function call.  Unresolved function calls are treated as normal function calls,
and may result in false positives when the builtin logical operator is used.
Have the unsequenced checker ignore dependent expressions to avoid this
false positive.  The check also happens in template instantiations to catch
when the overloaded operator is used.

llvm-svn: 277866
2016-08-05 21:02:34 +00:00
Richard Smith e3dbfe04b7 Teach -Wunsequenced that the side-effects of a function evaluation are sequenced
before the value computation of the result. In C, this is implied by there being
a sequence point after their evaluation, and in C++, it's implied by the
side-effects being sequenced before the expressions and statements in the
function body.

llvm-svn: 185282
2013-06-30 10:40:20 +00:00
Richard Smith 83e37bee44 PR16467: Teach -Wunsequenced that in C11 (unlike C++11), an assignment's
side-effect is not sequenced before its value computation. Also fix a
mishandling of ?: expressions where the condition is constant that was
exposed by the tests for this.

llvm-svn: 185035
2013-06-26 23:16:51 +00:00
Richard Smith 5011a0022a Some builtins do not evaluate their arguments. Teach EvaluatedExprVisitor not
to visit them.

llvm-svn: 172769
2013-01-17 23:46:04 +00:00
Richard Smith 01a7fba820 -Wunsequenced: if the LHS of an &&, || or ?: is not constant, check for
unsequenced operations in the RHS. We don't compare the RHS with the rest of
the expression yet; such checks will need care to avoid diagnosing unsequenced
operations which are both in conditionally-evaluated subexpressions which
actually can't occur together, such as in '(b && ++x) + (!b && ++x)'.

llvm-svn: 172760
2013-01-17 22:06:26 +00:00
Richard Smith c406cb7364 Add -Wunsequenced (with compatibility alias -Wsequence-point) to warn on
expressions which have undefined behavior due to multiple unsequenced
modifications or an unsequenced modification and use of a variable.

llvm-svn: 172690
2013-01-17 01:17:56 +00:00