We started diagnosing this situation with a more clear diagnostic
message, but it was pointed out that unevaluated contexts don't really
have the undefined behavior property as there is no runtime access
involved.
This augments the changes in https://reviews.llvm.org/D122656 to not
diagnose in an unevaluated context.
Member access for an atomic structure or union is unconditional
undefined behavior (C11 6.5.2.3p5). However, we would issue a confusing
error message about the base expression not being a structure or union
type.
GCC issues a warning for this case. Clang now warns as well, but the
warning is defaulted to an error because the actual access is still
unsafe.
This fixes Issue 54563.
In C, assignment expressions result in an rvalue whose type is the type
of the lhs of the assignment after it undergoes lvalue to rvalue
conversion. lvalue to rvalue conversion in C strips all qualifiers
including _Atomic.
We used getUnqualifiedType() which does not strip the _Atomic qualifier
when we should have used getAtomicUnqualifiedType(). This corrects the
usage and adds some comments to getUnqualifiedType() to make it more
clear that it does not strip _Atomic and that's on purpose (see C11
6.2.5p27).
This addresses Issue 48742.
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 first batch of tests being updated (there are a significant
number of other tests left to be updated).
This fixes a couple of asserts when analyzing comparisons involving
C11 atomics that were uncovered by r205608 when we extended the
applicability of -Wtautological-constant-out-of-range-compare.
llvm-svn: 213573
Use UsualArithmeticConversions unconditionally in analysis of
comparisons and conditional operators: the method performs
the usual arithmetic conversions if both sides are arithmetic, and
usual unary conversions if they are not. This is just a cleanup
for conditional operators; for comparisons, it fixes the issue that
we would try to check isArithmetic() on an atomic type.
Also, fix GetExprRange() in SemaChecking.cpp so it deals with variables
of atomic type correctly.
Fixes PR15537.
llvm-svn: 185857
Aaron Ballman