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
This makes use of the changes introduced in D134604, in order to
instantiate alias templates witn a final sugared substitution.
This comes at no additional relevant cost.
Since we don't track / unique them in specializations, we wouldn't be
able to resugar them later anyway.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136565
This makes use of the changes introduced in D134604, in order to
instantiate non-type template parameters and default template arguments
with a final sugared substitution.
This comes at no additional relevant cost.
Since we don't track / unique them in specializations, we wouldn't be
able to resugar them later anyway.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136564
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
Since these are much like template type aliases, where we don't
track a specialization for them and just substitute them eagerly,
we can't resugar them anyway, and there is no relevant cost in just
performing a finalizing sugared substitution.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136563
Makes CheckTemplateArgumentList and the template deduction functions
produce a sugared converted argument list in addition to the canonical one.
This is mostly NFC except that we hook this up to a few diagnostics in
SemaOverload.
The infrastructure here will be used in subsequent patches
where we perform a finalized sugared substitution for entities
which we do not unique per specializations on canonical arguments,
and later on will be used for template specialization resugaring.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D133874
This reverts commit dc170433137aeda5e5276bd292cac12aa93fee7c.
Breaks building LLVM on mac when targeting macOS before 10.15, see
comments on https://reviews.llvm.org/D136533
Removes a bunch of obsolete methods in favor of a single one returning
an ArrayRef of TemplateArgument.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D136602
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
The way this code checks whether a pointer is null is wrong for other
reasons; it doesn't actually check whether a null pointer constant is a
"constant" in the C++ standard sense. But this fix at least makes sure
we don't treat a non-null pointer as if it were null.
Fixes https://github.com/llvm/llvm-project/issues/57883
Differential Revision: https://reviews.llvm.org/D134928
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
As another regression from the Deferred Concepts Instantiation patch, we
weren't properly detecting that a friend referenced its containing
Record when it referred to it without its template parameters. This
patch makes sure that we do.
Previously we were stripping these normally inherited attributes during
explicit specialization. However for class template member functions
(but not function templates), MSVC keeps the attribute.
This makes Clang match that behavior, and fixes GitHub issue #54717
Differential revision: https://reviews.llvm.org/D135154
As @mizvekov suggested in D134772. This works great for D128750 when
dealing with AutoType's.
Reviewed By: mizvekov, erichkeane
Differential Revision: https://reviews.llvm.org/D135088
As fallout of the Deferred Concept Instantiation patch (babdef27c5), we
got a number of reports of a regression, where we asserted when
instantiating a constraint on a generic lambda inside of a variable
template. See: https://github.com/llvm/llvm-project/issues/57958
The problem was that getTemplateInstantiationArgs function only walked
up declaration contexts, and missed that this is not necessarily the
case with a lambda (which can ALSO be in a separate context).
This patch refactors the getTemplateInstantiationArgs function in a way
that is hopefully more readable, and fixes the problem with the concepts
on a generic lambda.
Differential Revision: https://reviews.llvm.org/D134874
This implements WG14 N2927 and WG14 N2930, which together define the
feature for typeof and typeof_unqual, which get the type of their
argument as either fully qualified or fully unqualified. The argument
to either operator is either a type name or an expression. If given a
type name, the type information is pulled directly from the given name.
If given an expression, the type information is pulled from the
expression. Recursive use of these operators is allowed and has the
expected behavior (the innermost operator is resolved to a type, and
that's used to resolve the next layer of typeof specifier, until a
fully resolved type is determined.
Note, we already supported typeof in GNU mode as a non-conforming
extension and we are *not* exposing typeof_unqual as a non-conforming
extension in that mode, nor are we exposing typeof or typeof_unqual as
a nonconforming extension in other language modes. The GNU variant of
typeof supports a form where the parentheses are elided from the
operator when given an expression (e.g., typeof 0 i = 12;). When in C2x
mode, we do not support this extension.
Differential Revision: https://reviews.llvm.org/D134286
This patch implements P0634r3 that removes the need for 'typename' in certain contexts.
For example,
```
template <typename T>
using foo = T::type; // ok
```
This is also allowed in previous language versions as an extension, because I think it's pretty useful. :)
Reviewed By: #clang-language-wg, erichkeane
Differential Revision: https://reviews.llvm.org/D53847
Apparently TransformDecl in TreeTransform can be called with a nullptr
for a Decl, so my casts were illegal. The fix here is to add an early
exit to my TransformDecl.
This reverts commit 95d94a67755620c0a2871ac6f056ca8e9731d5e9.
This implements the deferred concepts instantiation, which should allow
the libstdc++ ranges to properly compile, and for the CRTP to work for
constrained functions.
Since the last attempt, this has fixed the issues from @wlei and
@mordante.
Differential Revision: https://reviews.llvm.org/D126907
This change allows us to represent in the AST some specific
circumstances where we substitute a template parameter type
which is part of the underlying type of a previous substitution.
This presently happens in some circumstances dealing with
substitution of defaulted parameters of template template
parameters, and in some other cases during concepts substitution.
The main motivation for this change is for the future use in the
implementation of template specialization resugaring, as this will
allow us to represent a substitution with sugared types.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D132816
Implement suggested fix for [[ https://cplusplus.github.io/CWG/issues/2628.html | DR2628. ]] Couldn't update the DR docs because there hasn't been a DR index since it was filed, but the tests still run in CI.
Note: I only transfer the constructor constraints, not the struct constraints. I think that's OK because the struct constraints are the same
for all constructors so they don't affect the overload resolution, and if they deduce to something that doesn't pass the constraints
we catch it anyway. So (hopefully) that should be more efficient without sacrificing correctness.
Closes:
https://github.com/llvm/llvm-project/issues/57646https://github.com/llvm/llvm-project/issues/43829
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D134145
It is possible that we can pass a null ParamType to
CheckNonTypeTemplateParameter -- the ParamType var can be reset to a null
type on Line 6940, and the followed bailout if is not entered.
Differential Revision: https://reviews.llvm.org/D134180
We change the template specialization of builtin templates to
behave like aliases.
Though unlike real alias templates, these might still produce a canonical
TemplateSpecializationType when some important argument is dependent.
For example, we can't do anything about make_integer_seq when the
count is dependent, or a type_pack_element when the index is dependent.
We change type deduction to not try to deduce canonical TSTs of
builtin templates.
We also change those buitin templates to produce substitution sugar,
just like a real instantiation would, making the resulting type correctly
represent the template arguments used to specialize the underlying template.
And make_integer_seq will now produce a TST for the specialization
of it's first argument, which we use as the underlying type of
the builtin alias.
When performing member access on the resulting type, it's now
possible to map from a Subst* node to the template argument
as-written used in a regular fashion, without special casing.
And this fixes a bunch of bugs with relation to these builtin
templates factoring into deduction.
Fixes GH42102 and GH51928.
Depends on D133261
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D133262
This continues D111283 by extending the getCommonSugaredType
implementation to also merge non-canonical type nodes.
We merge these nodes by going up starting from the canonical
node, calculating their merged properties on the way.
If we reach a pair that is too different, or which we could not
otherwise unify, we bail out and don't try to keep going on to
the next pair, in effect striping out all the remaining top-level
sugar nodes. This avoids mismatching 'companion' nodes, such as
ElaboratedType, so that they don't end up elaborating some other
unrelated thing.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D130308
After upgrading the type deduction machinery to retain type sugar in
D110216, we were left with a situation where there is no general
well behaved mechanism in Clang to unify the type sugar of multiple
deductions of the same type parameter.
So we ended up making an arbitrary choice: keep the sugar of the first
deduction, ignore subsequent ones.
In general, we already had this problem, but in a smaller scale.
The result of the conditional operator and many other binary ops
could benefit from such a mechanism.
This patch implements such a type sugar unification mechanism.
The basics:
This patch introduces a `getCommonSugaredType(QualType X, QualType Y)`
method to ASTContext which implements this functionality, and uses it
for unifying the results of type deduction and return type deduction.
This will return the most derived type sugar which occurs in both X and
Y.
Example:
Suppose we have these types:
```
using Animal = int;
using Cat = Animal;
using Dog = Animal;
using Tom = Cat;
using Spike = Dog;
using Tyke = Dog;
```
For `X = Tom, Y = Spike`, this will result in `Animal`.
For `X = Spike, Y = Tyke`, this will result in `Dog`.
How it works:
We take two types, X and Y, which we wish to unify as input.
These types must have the same (qualified or unqualified) canonical
type.
We dive down fast through top-level type sugar nodes, to the
underlying canonical node. If these canonical nodes differ, we
build a common one out of the two, unifying any sugar they had.
Note that this might involve a recursive call to unify any children
of those. We then return that canonical node, handling any qualifiers.
If they don't differ, we walk up the list of sugar type nodes we dived
through, finding the last identical pair, and returning that as the
result, again handling qualifiers.
Note that this patch will not unify sugar nodes if they are not
identical already. We will simply strip off top-level sugar nodes that
differ between X and Y. This sugar node unification will instead be
implemented in a subsequent patch.
This patch also implements a few users of this mechanism:
* Template argument deduction.
* Auto deduction, for functions returning auto / decltype(auto), with
special handling for initializer_list as well.
Further users will be implemented in a subsequent patch.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D111283
This reverts commit d200db38637884fd0b421802c6094b2a03ceb29e, which causes a
clang crash. See https://reviews.llvm.org/D111283#3785755
Test case for convenience:
```
template <typename T>
using P = int T::*;
template <typename T, typename... A>
void j(P<T>, T, A...);
template <typename T>
void j(P<T>, T);
struct S {
int b;
};
void g(P<S> k, S s) { j(k, s); }
```
After upgrading the type deduction machinery to retain type sugar in
D110216, we were left with a situation where there is no general
well behaved mechanism in Clang to unify the type sugar of multiple
deductions of the same type parameter.
So we ended up making an arbitrary choice: keep the sugar of the first
deduction, ignore subsequent ones.
In general, we already had this problem, but in a smaller scale.
The result of the conditional operator and many other binary ops
could benefit from such a mechanism.
This patch implements such a type sugar unification mechanism.
The basics:
This patch introduces a `getCommonSugaredType(QualType X, QualType Y)`
method to ASTContext which implements this functionality, and uses it
for unifying the results of type deduction and return type deduction.
This will return the most derived type sugar which occurs in both X and
Y.
Example:
Suppose we have these types:
```
using Animal = int;
using Cat = Animal;
using Dog = Animal;
using Tom = Cat;
using Spike = Dog;
using Tyke = Dog;
```
For `X = Tom, Y = Spike`, this will result in `Animal`.
For `X = Spike, Y = Tyke`, this will result in `Dog`.
How it works:
We take two types, X and Y, which we wish to unify as input.
These types must have the same (qualified or unqualified) canonical
type.
We dive down fast through top-level type sugar nodes, to the
underlying canonical node. If these canonical nodes differ, we
build a common one out of the two, unifying any sugar they had.
Note that this might involve a recursive call to unify any children
of those. We then return that canonical node, handling any qualifiers.
If they don't differ, we walk up the list of sugar type nodes we dived
through, finding the last identical pair, and returning that as the
result, again handling qualifiers.
Note that this patch will not unify sugar nodes if they are not
identical already. We will simply strip off top-level sugar nodes that
differ between X and Y. This sugar node unification will instead be
implemented in a subsequent patch.
This patch also implements a few users of this mechanism:
* Template argument deduction.
* Auto deduction, for functions returning auto / decltype(auto), with
special handling for initializer_list as well.
Further users will be implemented in a subsequent patch.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D111283
Template arguments of template and declaration kind were being profiled
only by their canonical properties, which would cause incorrect
uniquing of constrained AutoTypes, leading to a crash in some cases.
This exposed some places in CheckTemplateArgumentList where non-canonical
arguments where being pushed into the resulting converted list.
We also throw in some asserts to catch early and explain the crashes.
Note that the fix for the 'declaration' kind is untestable at this point,
because there should be no cases right now in the AST where we try
to unique a non-canonical converted template argument.
This fixes GH55567.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Differential Revision: https://reviews.llvm.org/D133072
In Sema::LookupTemplateName(...) seeks to assert that the ObjectType is complete
or being defined. If the type is incomplete it will attempt to unconditionally
cast it to a TagType and not all incomplete types are a TagType. For example the
type could be void or it could be an IncompleteArray.
This change adds an additional check to confirm it is a TagType before attempting
to check if it is incomplete or being defined
Differential Revision: https://reviews.llvm.org/D132712
This reverts commit d483730d8c3fa2e0d4192b2f3c61c761b124e6ad.
This allegedly breaks a significant part of facebooks internal build.
Reverting while we wait for them to provide a reproducer of this from
@wlei.
This reverts commit 258c3aee54e11bc5c5d8ac137eb15e8d5bbcc7e4.
This should fix the libc++ issue that caused the revert, by re-designing
slightly how we determined when we should evaluate the constraints.
Additionally, many of the other components to the original patch (the
NFC parts) were committed separately to shrink the size of this patch
for review.
Differential Revision: https://reviews.llvm.org/D126907
Consider:
A == 5 && A != 5
IfA is 5, the old collectConjunctionTerms() would call itself again for
the LHS (which it ignores), then the RHS (which it also ignores) and
then just return without ever adding anything to the Terms array.
Differential Revision: https://reviews.llvm.org/D131070
In preperation of the deferred instantation progress, this patch
propagates the multi-level template argument lists further through the
API to reduce the size of that patch.
According to [basic.def.odr]p14, the same redeclarations in different TU
but not attached to a named module are allowed. But we didn't take care
of concept decl for this condition. This patch tries to fix this
problem.
Reviewed By: ilya-biryukov
Differention Revision: https://reviews.llvm.org/D130614
