Modify the IfStmt node to suppoort constant evaluated expressions.
Add a new ExpressionEvaluationContext::ImmediateFunctionContext to
keep track of immediate function contexts.
This proved easier/better/probably more efficient than walking the AST
backward as it allows diagnosing nested if consteval statements.
(This relands 59337263ab and makes sure comma operator
diagnostics are suppressed in a SFINAE context.)
While at it, add the diagnosis message "left operand of comma operator has no effect" (used by GCC) for comma operator.
This also makes Clang diagnose in the constant evaluation context which aligns with GCC/MSVC behavior. (https://godbolt.org/z/7zxb8Tx96)
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D103938
cxx_dr_status.html
I noticed that these two DRs are currently working correctly, so I
added a pair of lit tests that check the AST (which is most useful for
CWG1779, since 'dependent' is really only observable in an ast dump) to
make sure __func__ works correctly in dependent cases, and in lambda
operator().
Also noticed that CWG1762, mostly an 'example' change, works correctly,
so added a test so that it gets marked 'done' as well.
Additionally, I regenerated cxx_dr_status.html, updating it for Clang
13's release, based on the cwg_status.html from August 12, 2021.
Differential Revision: https://reviews.llvm.org/D109956
While at it, add the diagnosis message "left operand of comma operator has no effect" (used by GCC) for comma operator.
This also makes Clang diagnose in the constant evaluation context which aligns with GCC/MSVC behavior. (https://godbolt.org/z/7zxb8Tx96)
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D103938
This improves diagnostic (& important to me, DWARF) accuracy - otherwise
there could be ambiguities between "std::nullptr_t" and some user-defined
type that's /actually/ "nullptr_t" defined in the global namespace.
Differential Revision: https://reviews.llvm.org/D110044
While at it, add the diagnosis message "left operand of comma operator has no effect" (used by GCC) for comma operator.
This also makes Clang diagnose in the constant evaluation context which aligns with GCC/MSVC behavior. (https://godbolt.org/z/7zxb8Tx96)
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D103938
Don't say we couldn't find an 'operator<=>' when we were actually
looking for an 'operator=='. Also fix a crash when attempting to
diagnose if we select a built-in 'operator!=' in this lookup.
See PR48617.
When assigning the new template arguments to the new TypeLoc, we were looping
on the argument count of the original TypeLoc instead of the new one,
which can be different when packs are present.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D109406
See PR51708.
Attempting copy elision in dependent contexts with invalid variable,
such as a variable with incomplete type, would cause a crash when attempting
to calculate it's alignment.
The fix is to just skip this optimization on invalid VarDecl, as otherwise this
provides no benefit to error recovery: This functionality does not try to
diagnose anything, it only calculates a flag which will affect where the
variable will be allocated during codegen.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rtrieu
Differential Revision: https://reviews.llvm.org/D109191
I discovered this quirk when working on some DWARF - AST printing prints
type template parameters fully qualified, but printed template template
parameters the way they were written syntactically, or wholely
unqualified - instead, we should print them consistently with the way we
print type template parameters: fully qualified.
The one place this got weird was for partial specializations like in
ast-print-temp-class.cpp - hence the need for checking for
TemplateNameDependenceScope::DependentInstantiation template template
parameters. (not 100% sure that's the right solution to that, though -
open to ideas)
Differential Revision: https://reviews.llvm.org/D108794
In LLVM IR, `AlignmentBitfieldElementT` is 5-bit wide
But that means that the maximal alignment exponent is `(1<<5)-2`,
which is `30`, not `29`. And indeed, alignment of `1073741824`
roundtrips IR serialization-deserialization.
While this doesn't seem all that important, this doubles
the maximal supported alignment from 512MiB to 1GiB,
and there's actually one noticeable use-case for that;
On X86, the huge pages can have sizes of 2MiB and 1GiB (!).
So while this doesn't add support for truly huge alignments,
which i think we can easily-ish do if wanted, i think this adds
zero-cost support for a not-trivially-dismissable case.
I don't believe we need any upgrade infrastructure,
and since we don't explicitly record the IR version,
we don't need to bump one either.
As @craig.topper speculates in D108661#2963519,
this might be an artificial limit imposed by the original implementation
of the `getAlignment()` functions.
Differential Revision: https://reviews.llvm.org/D108661
This adds the Unicode 13 data for XID_Start and XID_Continue.
The definition of valid identifier is changed in all C++ modes
as P1949 (https://wg21.link/p1949) was accepted by WG21 as a defect
report.
This patch implements paper P0692R1 from the C++20 standard. Disable usual access checking rules to template argument names in a declaration of partial specializations, explicit instantiation or explicit specialization (C++20 13.7.5/10, 13.9.1/6).
Fixes: https://llvm.org/PR37424
This patch also implements option *A* from this paper P0692R1 from the C++20 standard.
This patch follows the @rsmith suggestion from D78404.
Reviewed By: krisb
Differential Revision: https://reviews.llvm.org/D92024
Before this patch, CXXCtorInitializers that don't typecheck get discarded in
most cases. In particular:
- typos that can't be corrected don't turn into RecoveryExpr. The full expr
disappears instead, and without an init expr we discard the node.
- initializers that fail initialization (e.g. constructor overload resolution)
are discarded too.
This patch addresses both these issues (a bit clunkily and repetitively, for
member/base/delegating initializers)
It does not preserve any AST nodes when the member/base can't be resolved or
other problems of that nature. That breaks invariants of CXXCtorInitializer
itself, and we don't have a "weak" RecoveryCtorInitializer like we do for Expr.
I believe the changes to diagnostics in existing tests are improvements.
(We're able to do some analysis on the non-broken parts of the initializer)
Differential Revision: https://reviews.llvm.org/D101641
The diagnostic texts for warning on attributes that don't appear on the
initial declaration is generally useful. We'd like to re-use it in
D106030, but first let's combine two that already are very similar so we
may re-use it a third time in that commit.
Also, fix a few places that were using notePreviousDefinition to point
to declarations, to instead use diag::note_previous_declaration.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D107613
See PR48656.
The implementation of the template instantiation of requires expressions
was incorrectly trying to get the expression from an 'ExprRequirement'
before checking if it was an error state.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D107399
See PR47174.
When canonicalizing nested name specifiers of the type kind,
the prefix for 'DependentTemplateSpecialization' types was being
dropped, leading to malformed types which would cause failures
when rebuilding template names.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D107311
When substitution failed on the first constrained template argument (but
only the first), we would assert / crash. Checking for failure was only
being performed from the second constraint on.
This changes it so the checking is performed in that case,
and the code is also now simplified a little bit to hopefully
avoid this confusion.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D106907
After taking C++98 implicit moves out in D104500,
we put it back in, but now in a new form which preserves
compatibility with pure C++98 programs, while at the same time
giving almost all the goodies from P1825.
* We use the exact same rules as C++20 with regards to which
id-expressions are move eligible. The previous
incarnation would only benefit from the proper subset which is
copy ellidable. This means we can implicit move, in addition:
* Parameters.
* RValue references.
* Exception variables.
* Variables with higher-than-natural required alignment.
* Objects with different type from the function return type.
* We preserve the two-overload resolution, with one small tweak to the
first one: If we either pick a (possibly converting) constructor which
does not take an rvalue reference, or a user conversion operator which
is not ref-qualified, we abort into the second overload resolution.
This gives C++98 almost all the implicit move patterns which we had created test
cases for, while at the same time preserving the meaning of these
three patterns, which are found in pure C++98 programs:
* Classes with both const and non-const copy constructors, but no move
constructors, continue to have their non-const copy constructor
selected.
* We continue to reject as ambiguous the following pattern:
```
struct A { A(B &); };
struct B { operator A(); };
A foo(B x) { return x; }
```
* We continue to pick the copy constructor in the following pattern:
```
class AutoPtrRef { };
struct AutoPtr {
AutoPtr(AutoPtr &);
AutoPtr();
AutoPtr(AutoPtrRef);
operator AutoPtrRef();
};
AutoPtr test_auto_ptr() {
AutoPtr p;
return p;
}
```
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: Quuxplusone
Differential Revision: https://reviews.llvm.org/D105756
Support Narrowing conversions to bool in if constexpr condition
under C++23 language mode.
Only if constexpr is implemented as the behavior of static_assert
is already conforming. Still need to work on explicit(bool) to
complete support.
Named return of a variable with aligned attribute would
trip an assert in case alignment was dependent.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D105380
This extends the effects of [[ http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1825r0.html | P1825 ]] to all C++ standards from C++11 up to C++20.
According to Motion 23 from Cologne 2019, P1825R0 was accepted as a Defect Report, so we retroactively apply this all the way back to C++11.
Note that we also remove implicit moves from C++98 as an extension
altogether, since the expanded first overload resolution from P1825
can cause some meaning changes in C++98.
For example it can change which copy constructor is picked when both const
and non-const ones are available.
This also rips out warn_return_std_move since there are no cases where it would be worthwhile to suggest it.
This also fixes a bug with bailing into the second overload resolution
when encountering a non-rvref qualified conversion operator.
This was unnoticed until now, so two new test cases cover these.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D104500
Word on the grapevine was that the committee had some discussion that
ended with unanimous agreement on eliminating relational function pointer comparisons.
We wanted to be bold and just ban all of them cold turkey.
But then we chickened out at the last second and are going for
eliminating just the spaceship overload candidate instead, for now.
See D104680 for reference.
This should be fine and "safe", because the only possible semantic change this
would cause is that overload resolution could possibly be ambiguous if
there was another viable candidate equally as good.
But to save face a little we are going to:
* Issue an "error" for three-way comparisons on function pointers.
But all this is doing really is changing one vague error message,
from an "invalid operands to binary expression" into an
"ordered comparison of function pointers", which sounds more like we mean business.
* Otherwise "warn" that comparing function pointers like that is totally
not cool (unless we are told to keep quiet about this).
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D104892
This implements a more comprehensive fix than was done at D95409.
Instead of excluding just function pointer subobjects, we also
exclude any user-defined function pointer conversion operators.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D103855
Fixes PR50591.
When analyzing classes with members which have user-defined conversion
operators to builtin types, the defaulted comparison analyzer was
picking the member type instead of the type for the builtin operator
which was selected as the best match.
This could either result in wrong comparison category being selected,
or a crash when runtime checks are enabled.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D103760
This change caused build errors related to move-only __block variables,
see discussion on https://reviews.llvm.org/D99696
> This expands NRVO propagation for more cases:
>
> Parse analysis improvement:
> * Lambdas and Blocks with dependent return type can have their variables
> marked as NRVO Candidates.
>
> Variable instantiation improvements:
> * Fixes crash when instantiating NRVO variables in Blocks.
> * Functions, Lambdas, and Blocks which have auto return type have their
> variables' NRVO status propagated. For Blocks with non-auto return type,
> as a limitation, this propagation does not consider the actual return
> type.
>
> This also implements exclusion of VarDecls which are references to
> dependent types.
>
> Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
>
> Reviewed By: Quuxplusone
>
> Differential Revision: https://reviews.llvm.org/D99696
This also reverts the follow-on change which was hard to tease apart
form the one above:
> "[clang] Implement P2266 Simpler implicit move"
>
> This Implements [[http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2266r1.html|P2266 Simpler implicit move]].
>
> Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
>
> Reviewed By: Quuxplusone
>
> Differential Revision: https://reviews.llvm.org/D99005
This reverts commits 1e50c3d785 and
bf20631782.
This adds support for p1099's 'using SCOPED_ENUM::MEMBER;'
functionality, bringing a member of an enumerator into the current
scope. The novel feature here, is that there need not be a class
hierarchical relationship between the current scope and the scope of
the SCOPED_ENUM. That's a new thing, the closest equivalent is a
typedef or alias declaration. But this means that
Sema::CheckUsingDeclQualifier needs adjustment. (a) one can't call it
until one knows the set of decls that are being referenced -- if
exactly one is an enumerator, we're in the new territory. Thus it
needs calling later in some cases. Also (b) there are two ways we hold
the set of such decls. During parsing (or instantiating a dependent
scope) we have a lookup result, and during instantiation we have a set
of shadow decls. Thus two optional arguments, at most one of which
should be non-null.
Differential Revision: https://reviews.llvm.org/D100276
The following was found by a customer and is accepted by the other primary
C++ compilers, but fails to compile in Clang:
namespace sss {
double foo(int, double);
template <class T>
T foo(T); // note: target of using declaration
} // namespace sss
namespace oad {
void foo();
}
namespace oad {
using ::sss::foo;
}
namespace sss {
using oad::foo; // note: using declaration
}
namespace sss {
double foo(int, double) { return 0; }
template <class T>
T foo(T t) { // error: declaration conflicts with target of using
return t;
}
} // namespace sss
I believe the issue is that MergeFunctionDecl() was calling
checkUsingShadowRedecl() but only considering a FunctionDecl as a
possible shadow and not FunctionTemplateDecl. The changes in this patch
largely mirror how variable declarations were being handled by also
catching FunctionTemplateDecl.
Non-comprehensive list of cases:
* Dumping template arguments;
* Corresponding parameter contains a deduced type;
* Template arguments are for a DeclRefExpr that hadMultipleCandidates()
Type information is added in the form of prefixes (u8, u, U, L),
suffixes (U, L, UL, LL, ULL) or explicit casts to printed integral template
argument, if MSVC codeview mode is disabled.
Differential revision: https://reviews.llvm.org/D77598
These proposals make the same changes to both C++ and C and remove a
restriction on standard attributes appearing multiple times in the same
attribute list.
We could warn on the duplicate attributes, but do not. This is for
consistency as we do not warn on attributes duplicated within the
attribute specifier sequence. If we want to warn on duplicated
standard attributes, we should do so both for both situations:
[[foo, foo]] and [[foo]][[foo]].
Clang currently has a bug where it allows you to write [[foo bar]] and
both attributes are silently accepted. This patch corrects the comma
parsing rules for such attributes and handles the test case fallout, as
a few tests were accidentally doing this.
This reworks a small set of tests, as preparatory work for implementing
P2266.
* Run for more standard versions, including c++2b.
* Normalize file names and run commands.
* Adds some extra tests.
New Coroutine tests taken from Aaron Puchert's D68845.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D99225
Arthur Eubanks