This patch reapplies #114258, fixing an infinite recursion bug in
`ASTImporter` that occurs when importing the primary template of a class
template specialization when the latest redeclaration of that template
is a friend declaration in the primary template.
This patch fixes a couple of regressions introduced in #111852.
Consider:
```
template<typename T>
struct A
{
template<bool U>
static constexpr bool f() requires U
{
return true;
}
};
template<>
template<bool U>
constexpr bool A<short>::f() requires U
{
return A<long>::f<U>();
}
template<>
template<bool U>
constexpr bool A<long>::f() requires U
{
return true;
}
static_assert(A<short>::f<true>()); // crash here
```
This crashes because when collecting template arguments from the _first_
declaration of `A<long>::f<true>` for constraint checking, we don't add
the template arguments from the enclosing class template specialization
because there exists another redeclaration that is a member
specialization.
This also fixes the following example, which happens for a similar
reason:
```
// input.cppm
export module input;
export template<int N>
constexpr int f();
template<int N>
struct A {
template<int J>
friend constexpr int f();
};
template struct A<0>;
template<int N>
constexpr int f() {
return N;
}
```
```
// input.cpp
import input;
static_assert(f<1>() == 1); // error: static assertion failed
```
Currently, we store injected template arguments in
`RedeclarableTemplateDecl::CommonBase`. This approach has a couple
problems:
1. We can only access the injected template arguments of
`RedeclarableTemplateDecl` derived types, but other `Decl` kinds still
make use of the injected arguments (e.g.
`ClassTemplatePartialSpecializationDecl`,
`VarTemplatePartialSpecializationDecl`, and `TemplateTemplateParmDecl`).
2. Accessing the injected template arguments requires the common data
structure to be allocated. This may occur before we determine whether a
previous declaration exists (e.g. when comparing constraints), so if the
template _is_ a redeclaration, we end up discarding the common data
structure.
This patch moves the storage and access of injected template arguments
from `RedeclarableTemplateDecl` to `TemplateParameterList`.
After #111852 refactored multi-level template argument list collection,
the following results in a crash:
```
template<typename T, bool B>
struct A;
template<bool B>
struct A<int, B>
{
void f() requires B;
};
template<bool B>
void A<int, B>::f() requires B { } // crash here
```
This happens because when collecting template arguments for constraint
normalization from a partial specialization, we incorrectly use the
template argument list of the partial specialization. We should be using
the template argument list of the _template-head_ (as defined in
[temp.arg.general] p2). Fixes#112222.
This patch reapplies #111173, fixing a bug when instantiating dependent
expressions that name a member template that is later explicitly
specialized for a class specialization that is implicitly instantiated.
The bug is addressed by adding the `hasMemberSpecialization` function,
which return `true` if _any_ redeclaration is a member specialization.
This is then used when determining the instantiation pattern for a
specialization of a template, and when collecting template arguments for
a specialization of a template.
Reapplies #106585, fixing an issue where non-dependent names of member
templates appearing prior to that member template being explicitly
specialized for an implicitly instantiated class template specialization
would incorrectly use the definition of the explicitly specialized
member template.
This implements the logic of the `common_type` base template as a
builtin alias. If there should be no `type` member, an empty class is
returned. Otherwise a specialization of a `type_identity`-like class is
returned. The base template (i.e. `std::common_type`) as well as the
empty class and `type_identity`-like struct are given as arguments to
the builtin.
Currently, clang rejects the following explicit specialization of `f`
due to the constraints not being equivalent:
```
template<typename T>
struct A
{
template<bool B>
void f() requires B;
};
template<>
template<bool B>
void A<int>::f() requires B { }
```
This happens because, in most cases, we do not set the flag indicating
whether a `RedeclarableTemplate` is an explicit specialization of a
member of an implicitly instantiated class template specialization until
_after_ we compare constraints for equivalence. This patch addresses the
issue (and a number of other issues) by:
- storing the flag indicating whether a declaration is a member
specialization on a per declaration basis, and
- significantly refactoring `Sema::getTemplateInstantiationArgs` so we
collect the right set of template argument in all cases.
Many of our declaration matching & constraint evaluation woes can be
traced back to bugs in `Sema::getTemplateInstantiationArgs`. This
change/refactor should fix a lot of them. It also paves the way for
fixing #101330 and #105462 per my suggestion in #102267 (which I have
implemented on top of this patch but will merge in a subsequent PR).
This addresses the FIXME in the code. There will be tests for the new
behavior in an upcoming #86265, which also addresses other bugs that
prevent exposing the wrong results of `ContainsUnexpandedPacks` in the
outputs of the compiler without crashes.
Now we can create a LocalDeclID directly with an integer without
verifying. It may be hard to refactor if we want to change the way we
serialize DeclIDs (See https://github.com/llvm/llvm-project/pull/95897).
Also it is hard for us to debug if someday someone construct a
LocalDeclID with an incorrect value.
So in this patch, I tried to unify the way we can construct a
LocalDeclID in ASTReader, where we will construct the LocalDeclID from
the serialized data. Also, now we can verify the constructed LocalDeclID
sooner in the new interface.
This patch improves the preservation of qualifiers and loss of type
sugar in TemplateNames.
This problem is analogous to https://reviews.llvm.org/D112374 and this
patch takes a very similar approach to that patch, except the impact
here is much lesser.
When a TemplateName was written bare, without qualifications, we
wouldn't produce a QualifiedTemplate which could be used to disambiguate
it from a Canonical TemplateName. This had effects in the TemplateName
printer, which had workarounds to deal with this, and wouldn't print the
TemplateName as-written in most situations.
There are also some related fixes to help preserve this type sugar along
the way into diagnostics, so that this patch can be properly tested.
- Fix dropping the template keyword.
- Fix type deduction to preserve sugar in TST TemplateNames.
This is an enabler for https://github.com/llvm/llvm-project/pull/92855
This allows an NTTP default argument to be set as an arbitrary
TemplateArgument, not just an expression.
This allows template parameter packs to have default arguments in the
AST, even though the language proper doesn't support the syntax for it.
This allows NTTP default arguments to be other kinds of arguments, like
packs, integral constants, and such.
This is an enabler for a future patch.
This allows an type-parameter default argument to be set as an arbitrary
TemplateArgument, not just a type.
This allows template parameter packs to have default arguments in the
AST, even though the language proper doesn't support the syntax for it.
This will be used in a later patch which synthesizes template parameter
lists with arbitrary default arguments taken from template
specializations.
There are a few places we used SubsType, because we only had a type, now
we use SubstTemplateArgument.
SubstTemplateArgument was missing arguments for setting Instantiation
location and entity names.
Adding those is needed so we don't regress in diagnostics.
Our current method of storing the template arguments as written for
`(Class/Var)Template(Partial)SpecializationDecl` suffers from a number
of flaws:
- We use `TypeSourceInfo` to store `TemplateArgumentLocs` for class
template/variable template partial/explicit specializations. For
variable template specializations, this is a rather unintuitive hack (as
we store a non-type specialization as a type). Moreover, we don't ever
*need* the type as written -- in almost all cases, we only want the
template arguments (e.g. in tooling use-cases).
- The template arguments as written are stored in a number of redundant
data members. For example, `(Class/Var)TemplatePartialSpecialization`
have their own `ArgsAsWritten` member that stores an
`ASTTemplateArgumentListInfo` (the template arguments).
`VarTemplateSpecializationDecl` has yet _another_ redundant member
"`TemplateArgsInfo`" that also stores an `ASTTemplateArgumentListInfo`.
This patch eliminates all
`(Class/Var)Template(Partial)SpecializationDecl` members which store the
template arguments as written, and turns the `ExplicitInfo` member into
a `llvm::PointerUnion<const ASTTemplateArgumentListInfo*,
ExplicitInstantiationInfo*>` (to avoid unnecessary allocations when the
declaration isn't an explicit instantiation). The template arguments as
written are now accessed via `getTemplateArgsWritten` in all cases.
The "most breaking" change is to AST Matchers, insofar that `hasTypeLoc`
will no longer match class template specializations (since they no
longer store the type as written).
This patch tries to remove all the direct use of DeclID except the real
low level reading and writing. All the use of DeclID is converted to
the use of LocalDeclID or GlobalDeclID. This is helpful to increase the
readability and type safety.
This patch tries to remove all the direct use of DeclID except the real
low level reading and writing. All the use of DeclID is converted to
the use of LocalDeclID or GlobalDeclID. This is helpful to increase the
readability and type safety.
Previously, the DeclID is defined in serialization/ASTBitCodes.h under
clang::serialization namespace. However, actually the DeclID is not
purely used in serialization part. The DeclID is already widely used in
AST and all around the clang project via classes like `LazyPtrDecl` or
calling `ExternalASTSource::getExernalDecl()`. All such uses are via the
raw underlying type of `DeclID` as `uint32_t`. This is not pretty good.
This patch moves the DeclID class family to a new header `AST/DeclID.h`
so that the whole project can use the wrapped class `DeclID`,
`GlobalDeclID` and `LocalDeclID` instead of the raw underlying type.
This can improve the readability and the type safety.
This patch tries to use DeclID in the code bases to avoid use the raw
type 'uint32_t'. It is problematic to use the raw type 'uint32_t' if we
want to change the type of DeclID some day.
Previously we use 'unsigned' as the type of ID in 'CreateDeserialized'.
And the type of `DeclID` in serialization is 'uint32_t', so there is
minor inconsistency.
Also more importantly, if we want to extend the type of DeclID from
uint32_t to uint64_t, we may be in trouble due to we forgot updating the
a lot of 'CreateDeserialized'.
So this patch tries to use semantical type 'DeclID' for
'*Decl::CreateDeserialized' to make sure it is tightly consistent.
This patch adds a `Typename` bit-field to `TemplateTemplateParmDecl`
which stores whether the template template parameter was declared with
the `typename` keyword.
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 removes the `ClassScopeFunctionSpecializationDecl` `Decl` node, and
instead uses `DependentFunctionTemplateSpecializationInfo` to handle
such declarations. `DependentFunctionTemplateSpecializationInfo` is also
changed to store a `const ASTTemplateArgumentListInfo*` to be more in
line with `FunctionTemplateSpecializationInfo`.
This also changes `FunctionDecl::isFunctionTemplateSpecialization` to
return `true` for dependent specializations, and
`FunctionDecl::getTemplateSpecializationKind`/`FunctionDecl::getTemplateSpecializationKindForInstantiation`
to return `TSK_ExplicitSpecialization` for non-friend dependent
specializations (the same behavior as dependent class scope
`ClassTemplateSepcializationDecl` & `VarTemplateSepcializationDecl`).
Limit the #includes to the least necessary to still compile. Move the
"new" function into the .cpp file to remove the need to #include
ASTContext.h into ASTConcept.h.
Differential Revision: https://reviews.llvm.org/D159320
This patch adds a concept AST node (`ConceptLoc`) and uses it at the corresponding places.
There are three objects that might have constraints via concepts:
`TypeConstraint`, `ConceptSpecializationExpr` and `AutoTypeLoc`.
The first two inherit from `ConceptReference` while the latter has
the information about a possible constraint directly stored in `AutoTypeLocInfo`. It would be nice if the concept information would be stored the same way in all three cases.
Moreover the current structure makes it difficult to deal with these concepts. For example in Clangd accessing the locations of constraints of a `AutoTypeLoc` can only be done with quite ugly hacks.
So we think that it makes sense to create a new AST node for such concepts.
In details we propose the following:
- Rename `ConceptReference` to `ConceptLoc` (or something else what is approriate)
and make it the new AST node.
- `TypeConstraint` and `ConceptSpecializationExpr` do not longer inherit from `ConceptReference` but store a pointer to a `ConceptLoc`.
- `AutoTypeLoc` stores a pointer to `ConceptLoc` instead of storing the concept info in `AutoTypeLocInfo`.
This patch implements a first version of this idea which compiles and where the existing tests pass.
To make this patch as small as possible we keep the existing member functions to access concept data. Later these can be replaced by directly calling the corresponding functions of the `ConceptLoc`s.
Differential Revision: https://reviews.llvm.org/D155858
This patch adjust the getSourceRange() for the
VarTemplateSpecializationDecl and VarTemplatePartialSpecializationDecl,
such that the initializer is included if present:
```
template<typename T>
T temp = 1;
template<> double temp<double> = 1;
```
This patch makes it consistent with the behavior of
non-template variables with initializers and restores
behavior that was present before https://reviews.llvm.org/D139705.
n case, when the initializer is not present we still
include the template arguments in the source range,
which was required for fixing zero-initialization fix-it.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D146733
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
This reverts commit cecc9a92cfca71c1b6c2a35c5e302ab649496d11.
The problem ended up being how we were handling the lambda-context in
code generation: we were assuming any decl context here would be a
named-decl, but that isn't the case. Instead, we just replace it with
the concept's owning context.
Differential Revision: https://reviews.llvm.org/D136451
This reverts commit b876f6e2f28779211a829d7d4e841fe68885ae20.
Still getting build failures on PPC AIX that aren't obvious what is causing
them, so reverting while I try to figure this out.
This reverts commit b7c922607c5ba93db8b893d4ba461052af8317b5.
This seems to cause some problems with some modules related things,
which makes me think I should have updated the version-major in
ast-bit-codes? Going to revert to confirm this was a problem, then
change that and re-try a commit.
As that bug reports, the problem here is that the lambda's
'context-decl' was not set to the concept, and the lambda picked up
template arguments from the concept. SO, we failed to get the correct
template arguments in SemaTemplateInstantiate.
However, a Concept Specialization is NOT a decl, its an expression, so
we weren't able to put the concept in the decl tree like we needed.
This patch introduces a ConceptSpecializationDecl, which is the smallest
type possible to use for this purpose, containing only the template
arguments.
The net memory impliciation of this is turning a
trailing-objects into a pointer to a type with trailing-objects, so it
should be minor.
As future work, we may consider giving this type more responsibility, or
figuring out how to better merge duplicates, but as this is just a
template-argument collection at the moment, there isn't much value to
it.
Differential Revision: https://reviews.llvm.org/D136451
This is a change to how we represent type subsitution in the AST.
Instead of only storing the replaced type, we track the templated
entity we are substituting, plus an index.
We modify MLTAL to track the templated entity at each level.
Otherwise, it's much more expensive to go from the template parameter back
to the templated entity, and not possible to do in some cases, as when
we instantiate outer templates, parameters might still reference the
original entity.
This also allows us to very cheaply lookup the templated entity we saw in
the naming context and find the corresponding argument it was replaced
from, such as for implementing template specialization resugaring.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D131858
