Accessing the member of a structure or union which is _Atomic-qualified
is undefined behavior in C. We currently diagnose that with a warning
that defaults to an error. In turn, this means we reject a valid program
if the access it not reachable because of the error. e.g.,
if (0)
SomeAtomicStruct.Member = 12; // Was diagnosed
This silences the diagnostic if the member access is not reachable.
We are currently rejecting an _Atomic qualified integer in a switch statment.
This fixes the issue by doing an Lvalue conversion before trying to match on the type.
Fixes#65557
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D159522
C2x was finalized at the June 2023 WG14 meeting. The DIS is out for
balloting and the comment period for that closes later this year/early
next year. While that does leave an opportunity for more changes to the
standard during the DIS ballot resolution process, only editorial
changes are anticipated and as a result, the C committee considers C2x
to be final. The committee took a straw poll on what we'd prefer the
informal name of the standard be, and we decided it should be called
C23 regardless of what year ISO publishes it.
However, because the final publication is not out, this patch does not
add the language standard alias for the -std=iso9899:<year> spelling of
the standard mode; that will be added once ISO finally publishes the
document and the year chosen will match the publication date.
This also changes the value of __STDC_VERSION__ from the placeholder
value 202000L to the final value 202311L.
Subsequent patches will start renaming things from c2x to c23, cleaning
up documentation, etc.
Differential Revision: https://reviews.llvm.org/D157606
We were failing to strip off atomic qualification when forming the cast
destination type, but properly stripping off cvr qualification. Now we
accept atomic, qualified, or unqualified destination types.
Note: the semantics of the cast still drop the qualifier, so such a
cast does not result in an atomic rvalue.
Fixes https://github.com/llvm/llvm-project/issues/39596
The relevant language rule from C11 is 6.5.16.1p1: "the left operand is
an atomic, qualified, or unqualified pointer, and the right is a null
pointer constant; or". We correctly handled qualified or unqualified
pointer types, but failed to handle atomic-qualified pointer types. Now
we look through the atomic qualification before testing the constraint
requirements.
Fixes https://github.com/llvm/llvm-project/issues/49563
Differential Revision: https://reviews.llvm.org/D148730
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
