This patch removes on-stack `TemplateArgumentList`'s. They were primary used
to pass an `ArrayRef<TemplateArgument>` to
`Sema::getTemplateInstantiationArgs`, which had a `const
TemplateArgumentList*` parameter for the innermost template argument
list. Changing this parameter to an
`std::optional<ArrayRef<TemplateArgument>>` eliminates the need for
on-stack `TemplateArgumentList`'s, which in turn eliminates the need for
`TemplateArgumentList` to store a pointer to its template argument
storage (which is redundant in almost all cases, as it is an AST
allocated type).
This is a follow-up for the comparison of constraints on out-of-line
function template definitions. We require the instantiation of a
ParmVarDecl while transforming the expression if that Decl gets
referenced by a DeclRefExpr. However, we're not actually performing the
class or function template instantiation at the time of such comparison.
Therefore, let's map these parameters to themselves so that they get
preserved after the substitution.
Fixes https://github.com/llvm/llvm-project/issues/74447.
We preserve the trailing requires-expression during the lambda
expression transformation. In order to get those referenced parameters
inside a requires-expression properly resolved to the instantiated
decls, we intended to inject these 'original' `ParmVarDecls` to the
current instantiaion scope, at `Sema::SetupConstraintScope`.
The previous approach seems to overlook nested instantiation chains,
leading to the crash within a nested lambda followed by a requires
clause.
This fixes https://github.com/llvm/llvm-project/issues/73418.
... and only look at equivalence of substituted expressions, not results
of constraint satisfaction.
This is required by the standard when matching redeclarations.
Fixes#74314.
There is already some existing machinery for that in
`TemplateInstantiator` and `Sema` exposed separate functions for
substituting expressions with intention to do that:
- `Sema::SubstExpr` should not evaluate constraints.
- `Sema::SubstConstraintExpr` should.
However, both functions used to be equivalent. Introduce a new function
that does not evaluate constraint and use it when matching declarations.
Also change implementation of `SubstConstraintExpr` to call `SubstExpr`
directly so it's obvious they behave in the same way and add a FIXME to
call out that we might need to revamp this approach in the future.
Out of line class template declaration specializations aren't created at
the time they have their template arguments checked, so we previously
weren't doing any amount of work to substitute the constraints before
comparison. This resulted in the out of line definition's difference in
'depth' causing the constraints to compare differently.
This patch corrects that. Additionally, it handles ClassTemplateDecl
when collecting template arguments.
Fixes: #61763
Instantiating a lambda at a scope different from where it is defined
will paralyze clang if the trailing require clause refers to local
variables. This patch fixes this by re-adding the local variables to
`LocalInstantiationScope`.
Fixes#64462
BEFORE this patch, when clang handles constraints like C1 || C2 where C1 evaluates to false and C2 evaluates to true, it emitted irrelevant diagnostics about the falsity of C1.
This patch removes the irrelevant diagnostic information generated during the evaluation of C1 if C2 evaluates to true.
Fixes https://github.com/llvm/llvm-project/issues/54678
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D157526
Like concepts checking, a trailing return type of a lambda
in a dependent context may refer to captures in which case
they may need to be rebuilt, so the map of local decl
should include captures.
This patch reveal a pre-existing issue.
`this` is always recomputed by TreeTransform.
`*this` (like all captures) only become `const`
after the parameter list.
However, if try to recompute the value of `this` (in a parameter)
during template instantiation while determining the type of the call operator,
we will determine it to be const (unless the lambda is mutable).
There is no good way to know at that point that we are in a parameter
or not, the easiest/best solution is to transform the type of this.
Note that doing so break a handful of HLSL tests.
So this is a prototype at this point.
Fixes#65067Fixes#63675
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D159126
Like concepts checking, a trailing return type of a lambda
in a dependent context may refer to captures in which case
they may need to be rebuilt, so the map of local decl
should include captures.
This patch reveal a pre-existing issue.
`this` is always recomputed by TreeTransform.
`*this` (like all captures) only become `const`
after the parameter list.
However, if try to recompute the value of `this` (in a parameter)
during template instantiation while determining the type of the call operator,
we will determine it to be const (unless the lambda is mutable).
There is no good way to know at that point that we are in a parameter
or not, the easiest/best solution is to transform the type of this.
Note that doing so break a handful of HLSL tests.
So this is a prototype at this point.
Fixes#65067Fixes#63675
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D159126
When checking the constraint of a lambda, we need to respect the constness
of the call operator when establishing the type of capture variables.
In D124351, this was done by adding const to the captured variable...
However, that would change the type of the variable outside of the scope
of the lambda, which is clearly not the desired outcome.
Instead, to ensure const-correctness, we need to populate
a LambdaScopeInfo with the capture variables before checking the
constraints of a generic lambda.
There is no changelog as I'd like to tentatively propose we backport
this change to RC3 as it is a regression introduced in the Clang 17
cycle.
Fixes#61267
Reviewed By: aaron.ballman, #clang-language-wg
Differential Revision: https://reviews.llvm.org/D158433
A lambda call operator can be a templated entity -
and therefore have constraints while not being a function template
template<class T> void f() {
[]() requires false { }();
}
In that case, we would check the constraints of the call operator
which is non-viable. However, we would find a viable candidate:
the conversion operator to function pointer, and use it to
perform a surrogate call.
These constraints were not checked because:
* We never check the constraints of surrogate functions
* The lambda conversion operator has non constraints.
From the wording, it is not clear what the intent is but
it seems reasonable to expect the constraints of the lambda conversion
operator to be checked and it is consistent with GCC and MSVC.
This patch also improve the diagnostics for constraint failure
on surrogate calls.
Fixes#63181
Reviewed By: #clang-language-wg, aaron.ballman
Differential Revision: https://reviews.llvm.org/D154368
Close https://github.com/llvm/llvm-project/issues/62943.
The root cause for the issue is that we think the associated constraints
from the 'same' declaration in different module units are different
incorrectly. Since the constraints doesn't know anything about decls and
modules, we should fix the problem by getting the associated constraints
from the exactly the same declarations from different modules.
This is a regression from 6db007a0 that was reported in:
https://github.com/llvm/llvm-project/issues/62697
The assertion was because we require a code synthesis context for the
instantiation of templates, and this reproducer causes a comparison that
doesn't have a parent-template causing one to exists.
This patch fixes it by creating a ConstraintNormalization context.
Substitute constraints only for declarations with different lexical contexts.
This results in avoiding the substitution of constraints during the redeclaration check
inside a class (and by product caching the wrong substitution result).
Test plan: ninja check-all
Differential revision: https://reviews.llvm.org/D150730
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
This is a recommit of 3a54022934.
Differential revision: https://reviews.llvm.org/D146178
Sema.h is huge. This makes a small reduction to it by moving
EnterExpressionEvaluationContext into a new header, since it is an
independent component.
Differential Revision: https://reviews.llvm.org/D149796
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
This is a recommit of e3b1083e00.
Differential revision: https://reviews.llvm.org/D146178
This reverts commit e3b1083e00e62f5d157d15cb8c63a1c3dfdf12e2.
This was reverted because it breaks a number of libstdc++ examples, AND
required a workaround that causes hiding of legitimate bugs.
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
This is a recommit of 60bee9ff5445.
Differential revision: https://reviews.llvm.org/D146178
Reported by Coverity:
Big parameter passed by value
Copying large values is inefficient, consider passing by reference; Low, medium, and high size thresholds for detection can be adjusted.
1. Inside "SemaConcept.cpp" file, in subsumes<clang::Sema::MaybeEmitAmbiguousAtomicConstraintsDiagnostic(clang::NamedDecl *, llvm::ArrayRef<clang::Expr const *>, clang::NamedDecl *, llvm::ArrayRef<clang::Expr const *>)::[lambda(clang::AtomicConstraint const &, clang::AtomicConstraint const &) (instance 2)]>(llvm::SmallVector<llvm::SmallVector<clang::AtomicConstraint *, 2u>, 4u>, llvm::SmallVector<llvm::SmallVector<clang::AtomicConstraint *, 2u>, 4u>, T1): A large function call parameter exceeding the low threshold is passed by value.
i. pass_by_value: Passing parameter PDNF of type NormalForm (size 144 bytes) by value, which exceeds the low threshold of 128 bytes.
ii. pass_by_value: Passing parameter QCNF of type NormalForm (size 144 bytes) by value, which exceeds the low threshold of 128 bytes.
2. Inside "CodeGenAction.cpp" file, in clang::reportOptRecordError(llvm::Error, clang::DiagnosticsEngine &, clang::CodeGenOptions): A very large function call parameter exceeding the high threshold is passed by value.
i. pass_by_value: Passing parameter CodeGenOpts of type clang::CodeGenOptions const (size 1560 bytes) by value, which exceeds the high threshold of 512 bytes.
3. Inside "SemaCodeComplete.cpp" file, in HandleCodeCompleteResults(clang::Sema *, clang::CodeCompleteConsumer *, clang::CodeCompletionContext, clang::CodeCompletionResult *, unsigned int): A large function call parameter exceeding the low threshold is passed by value.
i. pass_by_value: Passing parameter Context of type clang::CodeCompletionContext (size 200 bytes) by value, which exceeds the low threshold of 128 bytes.
4. Inside "SemaConcept.cpp" file, in <unnamed>::SatisfactionStackRAII::SatisfactionStackRAII(clang::Sema &, clang::NamedDecl const *, llvm::FoldingSetNodeID): A large function call parameter exceeding the low threshold is passed by value.
i. pass_by_value: Passing parameter FSNID of type llvm::FoldingSetNodeID (size 144 bytes) by value, which exceeds the low threshold of 128 bytes.
Reviewed By: erichkeane, aaron.ballman
Differential Revision: https://reviews.llvm.org/D147708
This temporarily reverts commit
60bee9ff544541e83ffbd4be31923d0e8b644690.
The diff will be recommitted once the newly discovered
regressions are fixed.
This diff switches the approach to comparison of constraint expressions
to the new one based on template args substitution.
It continues the effort to fix our handling of out-of-line definitions
of constrained templates.
The associated GitHub issue: https://github.com/llvm/llvm-project/issues/61414
Test plan:
1/ ninja check-all
2/ bootstrapped Clang passes tests
Differential revision: https://reviews.llvm.org/D146178
This change reverts the functional change from D144626 but retains its
test. Instead of dealing with the possibility that a trailing requires
clause might have been rewritten into some other incorrect form, just
stop rewriting it.
No functionality changes intended.
Reviewed By: erichkeane, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D147281
Since P0857, part of C++20, a *lambda-expression* can contain a
*requires-clause* after its *template-parameter-list*.
While support for this was added as part of
eccc734a69c0c012ae3160887b65a535b35ead3e, one specific case isn't
handled properly, where the *requires-clause* consists of an
instantiation of a boolean variable template. This is due to a
diagnostic check which was written with the assumption that a
*requires-clause* can never be followed by a left parenthesis. This
assumption no longer holds for lambdas.
This diagnostic check would then attempt to perform a "recovery", but it
does so in a valid parse state, resulting in an invalid parse state
instead!
This patch adds a special case when parsing requires clauses of lambda
templates, to skip this diagnostic check.
Fixes https://github.com/llvm/llvm-project/issues/61278
Fixes https://github.com/llvm/llvm-project/issues/61387
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D146140
This implements P2036R3 and P2579R0.
That is, explicit, int, and implicit capture become visible
at the start of the parameter head.
Reviewed By: aaron.ballman, rupprecht, shafik
Differential Revision: https://reviews.llvm.org/D124351
This reverts commit d708a186b6a9b050d09558163dd353d9f738c82d (and typo fix e4bc9898ddbeb70bc49d713bbf863f050f21e03f). It causes a compilation error for this:
```
struct StringLiteral {
template <int N>
StringLiteral(const char (&array)[N])
__attribute__((enable_if(N > 0 && N == __builtin_strlen(array) + 1,
"invalid string literal")));
};
struct Message {
Message(StringLiteral);
};
void Func1() {
auto x = Message("x"); // Note: this is fine
// Note: "xx\0" to force a different type, StringLiteral<3>, otherwise this
// successfully builds.
auto y = [&](decltype(Message("xx"))) {};
// ^ fails with: repro.cc:18:13: error: reference to local variable 'array'
// declared in enclosing function 'StringLiteral::StringLiteral<3>'
(void)x;
(void)y;
}
```
More details posted to D124351.
This implements P2036R3 and P2579R0.
That is, explicit, int, and implicit capture become visible
at the start of the parameter head.
Reviewed By: aaron.ballman
Differential Revision: https://reviews.llvm.org/D124351
Fixes: #60323https://github.com/llvm/llvm-project/issues/60323
The problem is that we are profiling the 'Expr' components directly,
however when they contain an unresolved lookup, those canonicalize
identically. The result was the two versions of calls to 'go' were
canonicalized identically.
This patch fixes this by ensuring we consider the declaration the
constraint is attached to, when possible. When not, we skip the
diagnostic.
The result is that we are relaxing our diagnostic in some cases (Of
which I couldn't come up with a reproducer), such that we might see
overflows when evaluating constraints that depend on themselves in a way
that they are not attached to a declaration directly, such as if
they are nested requirements, though the hope is this won't be a
problem, since the 'parent' named constraint would catch this. I'm
hopeful that the 'worst case' is that we catch recursion 'later' in the
process, instead of immediately.
As came up in the discussion on
https://reviews.llvm.org/rG12cb1cb3720de8d164196010123ce1a8901d8122
We were asserting because the attempt to print a note found that our
source range for a immediately declared constraint (as a part of
Parameter Mapping Substitution) wasn't in order.
However, it doesn't really make sense to have the location of this be
the whole list of template arguments, as that would result in the range
being:
bool func(std::thing<char*> auto foo) {}
^^^^^^^^^^^^^^^
Even if done correctly. Instead, this patch makes the range be just
'foo' in this case (or a pointer right after 'auto' if unnamed).
This reverts commit b8064374b217db061213c561ec8f3376681ff9c8.
Based on the report here:
https://github.com/llvm/llvm-project/issues/59271
this produces a significant increase in memory use of the compiler and a
large compile-time regression. This patch reverts this so that we don't
branch for release with that issue.
> Dependent access checks.
Fixes: https://github.com/llvm/llvm-project/issues/53364
We previously ignored dependent access checks to private members.
These are visible only to the `RequiresExprBodyExpr` (through `PerformDependentDiagnositcs`) and not to the individual requirements.
---
> Non-dependent access checks.
Fixes: https://github.com/llvm/llvm-project/issues/53334
Access to members in a non-dependent context would always yield an
invalid expression. When it appears in a requires-expression, then this
is a hard error as this would always result in a substitution failure.
https://eel.is/c++draft/expr.prim.req#general-note-1
> Note 1: If a requires-expression contains invalid types or expressions in its requirements, and it does not appear within the declaration of a templated entity, then the program is ill-formed. — end note]
> If the substitution of template arguments into a requirement would always result in a substitution failure, the program is ill-formed; no diagnostic required.
The main issue here is the delaying of the diagnostics.
Use a `ParsingDeclRAIIObject` creates a separate diagnostic pool for diagnositcs associated to the `RequiresExprBodyDecl`.
This is important because dependent diagnostics should not be leaked/delayed to higher scopes (Eg. inside a template function or in a trailing requires). These dependent diagnostics must be attached to the `DeclContext` of the parameters of `RequiresExpr` (which is the `RequiresExprBodyDecl` in this case).
Non dependent diagnostics, on the other hand, should not delayed and surfaced as hard errors.
Differential Revision: https://reviews.llvm.org/D140547
This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated. The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.
This is part of an effort to migrate from llvm::Optional to
std::optional:
https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
Based on discussion on the core reflector, it was made clear that a
concept that depends on itself should be a hard error, not a constraint
failure. This patch implements a stack of constraint-checks-in-progress
to make sure we quit, rather than hitting stack-exhaustion.
Note that we DO need to be careful to make sure we still check
constraints properly that are caused by a previous constraint, but not
derived from (such as when a check causes us to check special member
function generation), so we cannot use the existing logic to see if this
is being instantiated.
This fixes https://github.com/llvm/llvm-project/issues/44304 and
https://github.com/llvm/llvm-project/issues/50891.
Differential Revision: https://reviews.llvm.org/D136975
concept
When we failed the lookup of the function, we tried to form a
RecoveryExpr that caused us to recursively re-check the same constraint,
which caused us to try to double-insert the satisfaction into the cache.
This patch makes us just return the inner-cached version instead. We DO
end up double-evaluating thanks to the recovery-expr, but there isn't a
good way around that.
template-template parameters. Although it effects whether a template can be
used as an argument for another template, the constraint seems not to
be checked, nor other major implementations (GCC, MSVC, et al.) check it.
Additionally, Part-A of the document seems to have been implemented.
So mark P0857R0 as completed.
Differential Revision: https://reviews.llvm.org/D134128
Since we don't unique specializations for concepts, we can just instantiate
them with the sugared template arguments, at negligible cost.
If we don't track their specializations, we can't resugar them later
anyway, and that would be more expensive than just instantiating them
sugared in the first place since it would require an additional pass.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136566
Implements the changes required to perform substitution with
non-canonical template arguments, and to 'finalize' them
by not placing 'Subst' nodes.
A finalized substitution means we won't resugar them later,
because these templates themselves were eagerly substituted
with the intended arguments at the point of use. We may still
resugar other templates used within those, though.
This patch does not actually implement any uses of this
functionality, those will be added in subsequent patches,
so expect no changes to existing tests.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D134604
