user interface and documentation, and update __cplusplus for C++20.
WG21 considers the C++20 standard to be finished (even though it still
has some more steps to pass through in the ISO process).
The old flag names are accepted for compatibility, as usual, and we
still have lots of references to C++2a in comments and identifiers;
those can be cleaned up separately.
The C++ rules briefly allowed this, but the rule changed nearly 10 years
ago and we never updated our implementation to match. However, we've
warned on this by default for a long time, and no other compiler accepts
(even as an extension).
Summary:
Due to a recent (but retroactive) C++ rule change, only sufficiently
C-compatible classes are permitted to be given a typedef name for
linkage purposes. Add an enabled-by-default warning for these cases, and
rephrase our existing error for the case where we encounter the typedef
name for linkage after we've already computed and used a wrong linkage
in terms of the new rule.
Reviewers: rjmccall
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D74103
constant initialization.
Removing this zeroing regressed our code generation in a few cases, also
fixed here. We now compute whether a variable has constant destruction
even if it doesn't have a constant initializer, by trying to destroy a
default-initialized value, and skip emitting a trivial default
constructor for a variable even if it has non-trivial (but perhaps
constant) destruction.
When used as qualified names, pseudo-destructors are always named as if
they were members of the type, never as members of the namespace
enclosing the type.
The language wording change forgot to update overload resolution to rank
implicit conversion sequences based on qualification conversions in
reference bindings. The anticipated resolution for that oversight is
implemented here -- we order candidates based on qualification
conversion, not only on top-level cv-qualifiers, including ranking
reference bindings against non-reference bindings if they differ in
non-top-level qualification conversions.
For OpenCL/C++, this allows reference binding between pointers with
differing (nested) address spaces. This makes the behavior of reference
binding consistent with that of implicit pointer conversions, as is the
purpose of this change, but that pre-existing behavior for pointer
conversions is itself probably not correct. In any case, it's now
consistently the same behavior and implemented in only one place.
This reinstates commit de21704ba9,
reverted in commit d8018233d1, with
workarounds for some overload resolution ordering problems introduced by
CWG2352.
The patch files section is redundant to https://llvm.org/docs/GettingStarted.html.
There is nothing clang specific here. We are talking about a monorepo after all.
While it may seem nice to have one single clang page which explains everything,
it's not: It doesn't cover the topics in sufficient depth, it's redundant to
other pages and it's hard to keep it up to date as we see with the svn
instructions.
This reverts commit de21704ba9.
Regressed/causes this to error due to ambiguity:
void f(const int * const &);
void f(int *);
int main() {
int * x;
f(x);
}
(in case it's important - the original case where this turned up was a
member function overload in a class template with, essentially:
f(const T1&)
f(T2*)
(where T1 == X const *, T2 == X))
It's not super clear to me if this ^ is expected behavior, in which case
I'm sorry about the revert & happy to look into ways to fix the original
code.
The language wording change forgot to update overload resolution to rank
implicit conversion sequences based on qualification conversions in
reference bindings. The anticipated resolution for that oversight is
implemented here -- we order candidates based on qualification
conversion, not only on top-level cv-qualifiers.
For OpenCL/C++, this allows reference binding between pointers with
differing (nested) address spaces. This makes the behavior of reference
binding consistent with that of implicit pointer conversions, as is the
purpose of this change, but that pre-existing behavior for pointer
conversions is itself probably not correct. In any case, it's now
consistently the same behavior and implemented in only one place.
Method '-[NSCoder decodeValueOfObjCType:at:]' is not only deprecated
but also a security hazard, hence a loud check.
Differential Revision: https://reviews.llvm.org/D71728
We don't yet advertise init capture packs, because I found some bugs
while testing it. We reject-valid and then crash on both of these:
template<int ...a> auto x = [...y = a] {};
template<int ...a> auto x = [y = a...] {};
This covers:
* usual arithmetic conversions (comparisons, arithmetic, conditionals)
between different enumeration types
* usual arithmetic conversions between enums and floating-point types
* comparisons between two operands of array type
The deprecation warnings are on-by-default (in C++20 compilations); it
seems likely that these forms will become ill-formed in C++23, so
warning on them now by default seems wise.
For the first two bullets, off-by-default warnings were also added for
all the cases where we didn't already have warnings (covering language
modes prior to C++20). These warnings are in subgroups of the existing
-Wenum-conversion (except that the first case is not warned on if either
enumeration type is anonymous, consistent with our existing
-Wenum-conversion warnings).
We add a new common html file that documents the available command line
tools. Also a new html is added for a brief description of CodeChecker,
this way complementing scan-build.
Differential Revision: https://reviews.llvm.org/D70439
Namely, for the following items:
- Handle constructors within new[];
- Handle constructors for default arguments.
Update the open projects page with a link to the newly added tests
and more hints for potential contributors.
Patch by Daniel Krupp!
Differential Revision: https://reviews.llvm.org/D69308
Summary: Working with Meike and others to improve the wording in this document.
Reviewers: klimek
Subscribers: mcrosier, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69351
This adds support for rewriting <, >, <=, and >= to a normal or reversed
call to operator<=>, for rewriting != to a normal or reversed call to
operator==, and for rewriting <=> and == to reversed forms of those same
operators.
Note that this is a breaking change for various C++17 code patterns,
including some in use in LLVM. The most common patterns (where an
operator== becomes ambiguous with a reversed form of itself) are still
accepted under this patch, as an extension (with a warning). I'm hopeful
that we can get the language rules fixed before C++20 ships, and the
extension warning is aimed primarily at providing data to inform that
decision.
llvm-svn: 375306
whose value is not ignored.
We don't warn on all the cases that are deprecated: specifically, we
choose to not warn for now if there are parentheses around the
assignment but its value is not actually used. This seems like a more
defensible rule, particularly for cases like sizeof(v = a), where the
parens are part of the operand rather than the sizeof syntax.
llvm-svn: 374135
Diagnose some now-deprecated uses of volatile types:
* as function parameter types and return types
* as the type of a structured binding declaration
* as the type of the lvalue operand of an increment / decrement /
compound assignment operator
This does not implement a check for the deprecation of simple
assignments whose results are used; that check requires somewhat
more complexity and will be addressed separately.
llvm-svn: 374133
Summary:
The overload resolution for enums with a fixed underlying type has changed in the C++14 standard. This patch implements the new rule.
Patch by Mark de Wever!
Reviewers: rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D65695
llvm-svn: 373866
This is mostly the same as the
[[clang::require_constant_initialization]] attribute, but has a couple
of additional syntactic and semantic restrictions.
In passing, I added a warning for the attribute form being added after
we have already seen the initialization of the variable (but before we
see the definition); that case previously slipped between the cracks and
the attribute was silently ignored.
llvm-svn: 370972
Richard Smith