Commit Graph

10 Commits

Author SHA1 Message Date
Aaron Ballman 22db4824b9 Use functions with prototypes when appropriate; NFC
A significant number of our tests in C accidentally use functions
without prototypes. This patch converts the function signatures to have
a prototype for the situations where the test is not specific to K&R C
declarations. e.g.,

  void func();

becomes

  void func(void);

This is the third batch of tests being updated (there are a significant
number of other tests left to be updated).
2022-02-07 09:25:01 -05:00
Bruno Ricci 8a571538df
[Sema] SequenceChecker: Fix handling of operator ||, && and ?:
The current handling of the operators ||, && and ?: has a number of false
positive and false negative. The issues for operator || and && are:

1. We need to add sequencing regions for the LHS and RHS as is done for the
   comma operator. Not doing so causes false positives in expressions like
   `((a++, false) || (a++, false))` (from PR39779, see PR22197 for another
    example).

2. In the current implementation when the evaluation of the LHS fails, the RHS
   is added to a worklist to be processed later. This results in false negatives
   in expressions like `(a && a++) + a`.

Fix these issues by introducing sequencing regions for the LHS and RHS, and by
not deferring the visitation of the RHS.

The issues with the ternary operator ?: are similar, with the added twist that
we should not warn on expressions like `(x ? y += 1 : y += 2)` since exactly
one of the 2nd and 3rd expression is going to be evaluated, but we should still
warn on expressions like `(x ? y += 1 : y += 2) = y`.

Differential Revision: https://reviews.llvm.org/D57747

Reviewed By: rsmith
2019-12-22 12:27:31 +00:00
Richard Smith 7d02ca4878 Use DiagRuntimeBehavior for -Wunsequenced to weed out false positives
where either the modification or the other access is unreachable.

This reverts r359984 (which reverted r359962). The bug in clang-tidy's
test suite exposed by the original commit was fixed in r360009.

llvm-svn: 360010
2019-05-06 04:14:01 +00:00
Simon Pilgrim 4c3fbbf635 Revert rL359962 : Use DiagRuntimeBehavior for -Wunsequenced to weed out false positives
where either the modification or the other access is unreachable.
........
Try to fix buildbots

llvm-svn: 359984
2019-05-05 17:10:05 +00:00
Richard Smith 5dbfa76334 Use DiagRuntimeBehavior for -Wunsequenced to weed out false positives
where either the modification or the other access is unreachable.

llvm-svn: 359962
2019-05-04 05:20:14 +00:00
Richard Smith f7d3048e5b Fix -Wunsequenced false-positives in code controlled by a branch on
__builtin_constant_p.

If the operand of __builtin_constant_p is not constant and has
side-effects, then code controlled by a branch on it is unreachable and
we should not emit runtime behavior warnings in such code.

llvm-svn: 359844
2019-05-02 23:21:28 +00:00
Richard Smith 1780d82f35 Teach EvaluatedExprVisitor that the condition and unselected branches of a
_Generic expression are unevaluated.

llvm-svn: 223266
2014-12-03 21:00:20 +00:00
Richard Smith e8efd99b24 PR21706: -Wunsequenced was missing warnings when leaving a sequenced region that contained side effects.
llvm-svn: 223184
2014-12-03 01:05:50 +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