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
The diagnostics engine is very smart about being passed a NamedDecl to
print as part of a diagnostic; it gets the "right" form of the name,
quotes it properly, etc. However, the result of using an unnamed tag
declaration was to print '' instead of anything useful.
This patch causes us to print the same information we'd have gotten if
we had printed the type of the declaration rather than the name of it,
as that's the most relevant information we can display.
Differential Revision: https://reviews.llvm.org/D134813
requires-expression
As reported: https://github.com/llvm/llvm-project/issues/57487
We properly treated a failed instantiation of a concept as a
unsatisified constraint, however, we need to do this at the 'requires
clause' level as well. This ensures that the parameters on a requires
clause that fail instantiation will cause a satisfaction failure.
This patch implements this by running requires parameter clause
instantiation under a SFINAE trap, then stores any such failure as a
requirement failure, so it can be diagnosed later.
Previously, a lambda expression in a dependent context with a default argument
containing an immediately invoked lambda expression would produce a closure
class object that, if invoked such that the default argument was used, resulted
in a compiler crash or one of the following assertion failures during code
generation. The failures occurred regardless of whether the lambda expressions
were dependent.
clang/lib/CodeGen/CGCall.cpp:
Assertion `(isGenericMethod || Ty->isVariablyModifiedType() || Ty.getNonReferenceType()->isObjCRetainableType() || getContext() .getCanonicalType(Ty.getNonReferenceType()) .getTypePtr() == getContext().getCanonicalType((*Arg)->getType()).getTypePtr()) && "type mismatch in call argument!"' failed.
clang/lib/AST/Decl.cpp:
Assertion `!Init->isValueDependent()' failed.
Default arguments in declarations in local context are instantiated along with
their enclosing function or variable template (since such declarations can't
be explicitly specialized). Previously, such instantiations were performed at
the same time that their associated parameters were instantiated. However, that
approach fails in cases like the following in which the context for the inner
lambda is the outer lambda, but construction of the outer lambda is dependent
on the parameters of the inner lambda. This change resolves this dependency by
delyaing instantiation of default arguments in local contexts until after
construction of the enclosing context.
template <typename T>
auto f() {
return [](T = []{ return T{}; }()) { return 0; };
}
Refactoring included with this change results in the same code now being used
to instantiate default arguments that appear in local context and those that
are only instantiated when used at a call site; previously, such code was
duplicated and out of sync.
Fixes https://github.com/llvm/llvm-project/issues/49178
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D133500
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 reverts commit 95d94a6775.
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 reverts commit d483730d8c.
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 258c3aee54.
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
Closing https://github.com/llvm/llvm-project/issues/56826.
The root cause for pr56826 is: when we collect the template args for the
friend, we need to judge if the friend lives in file context. However,
if the friend lives in ExportDecl lexically, the judgement here is
invalid.
The solution is easy. We should judge the non transparent context and
the ExportDecl is transparent context. So the solution should be good.
A main concern may be the patch doesn't handle all the places of the
same defect. I think it might not be bad since the patch itself should
be innocent.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D131651
This reverts commit d4d47e574e.
This fixes the lldb crash that was observed by ensuring that our
friend-'template contains reference to' TreeTransform properly handles a
TemplateDecl.
This reverts commit 2f20743952 because it
triggers an assertion when building an LLDB test program:
Assertion failed: (InstantiatingSpecializations.empty() && "failed to
clean up an InstantiatingTemplate?"), function ~Sema, file
/Users/buildslave/jenkins/workspace/lldb-cmake/llvm-project/clang/lib/Sema/Sema.cpp,
line 458.
More details in https://reviews.llvm.org/D126907.
Fixes#54629.
The crash is is caused by the double template instantiation.
See the added test. Here is what happens:
- Template arguments for the partial specialization get instantiated.
- This causes instantitation into the corrensponding requires
expression.
- `TemplateInsantiator` correctly handles instantiation of parameters
inside `RequiresExprBody` and instantiates the constraint expression
inside the `NestedRequirement`.
- To build the substituted `NestedRequirement`, `TemplateInsantiator`
calls `Sema::BuildNestedRequirement` calls
`CheckConstraintSatisfaction`, which results in another template
instantiation (with empty template arguments). This seem to be an
implementation detail to handle constraint satisfaction and is not
required by the standard.
- The recursive template instantiation tries to find the parameter
inside `RequiresExprBody` and fails with the corresponding assertion.
Note that this only happens as both instantiations happen with the class
partial template specialization set as `Sema.CurContext`, which is
considered a dependent `DeclContext`.
To fix the assertion, avoid doing the recursive template instantiation
and instead evaluate resulting expressions in-place.
Reviewed By: erichkeane
Differential Revision: https://reviews.llvm.org/D127487
This patch implements a necessary part of P0848, the overload resolution for destructors.
It is now possible to overload destructors based on constraints, and the eligible destructor
will be selected at the end of the class.
The approach this patch takes is to perform the overload resolution in Sema::ActOnFields
and to mark the selected destructor using a new property in FunctionDeclBitfields.
CXXRecordDecl::getDestructor is then modified to use this property to return the correct
destructor.
This closes https://github.com/llvm/llvm-project/issues/45614.
Reviewed By: #clang-language-wg, erichkeane
Differential Revision: https://reviews.llvm.org/D126194
This includes a fix for the libc++ issue I ran across with friend
declarations not properly being identified as overloads.
This reverts commit 45c07db31c.
Compared to the old implementation:
* In C++, we only recurse into aggregate classes.
* Unnamed bit-fields are not printed.
* Constant evaluation is supported.
* Proper conversion is done when passing arguments through `...`.
* Additional arguments are supported and are injected prior to the
format string; this directly supports use with `fprintf`, for example.
* An arbitrary callable can be passed rather than only a function
pointer. In particular, in C++, a function template or overload set is
acceptable.
* All text generated by Clang is printed via `%s` rather than directly;
this avoids issues where Clang's pretty-printing output might itself
contain a `%` character.
* Fields of types that we don't know how to print are printed with a
`"*%p"` format and passed by address to the print function.
* No return value is produced.
Reviewed By: aaron.ballman, erichkeane, yihanaa
Differential Revision: https://reviews.llvm.org/D124221
This reverts commit a97899108e.
The patch caused some problems with the libc++ `__range_adaptor_closure`
that I haven't been able to figure out the cause of, so I am reverting
while I figure out whether this is a solvable problem/issue with the
CFE, or libc++ depending on an older 'incorrect' behavior.
This reverts commit 0c31da4838.
I've solved the issue with the PointerUnion by making the
`FunctionTemplateDecl` pointer be a NamedDecl, that could be a
`FunctionDecl` or `FunctionTemplateDecl` depending. This is enforced
with an assert.
This reverts commit 4b6c2cd647.
The patch caused numerous ARM 32 bit build failures, since we added a
5th item to the PointerUnion, and went over the 2-bits available in the
32 bit pointers.
As reported here: https://github.com/llvm/llvm-project/issues/44178
Concepts are not supposed to be instantiated until they are checked, so
this patch implements that and goes through significant amounts of work
to make sure we properly re-instantiate the concepts correctly.
Differential Revision: https://reviews.llvm.org/D119544
The standard requires[0] member function constraints to be checked when
explicitly instantiating classes. This patch adds this constraints
check.
This issue is tracked as #46029 [1].
Note that there's an related open CWG issue (2421[2]) about what to do when
multiple candidates have satisfied constraints. This is particularly an
issue because mangling doesn't contain function constraints, and so the
following code still ICEs with definition with same mangled name
'_ZN1BIiE1fEv' as another definition:
template<class T>
struct B {
int f() requires std::same_as<T, int> {
return 0;
}
int f() requires (std::same_as<T, int> &&
!std::same_as<T, char>) {
return 1;
}
};
template struct B<int>;
Also note that the constraints checking while instantiating *functions*
is still not implemented. I started looking at it but It's a bit more
complicated. I believe in such a case we have to consider the partial
constraints order and potentially choose the best candidate out of the
set of multiple valid ones.
[0]: https://eel.is/c++draft/temp.explicit#10
[1]: https://github.com/llvm/llvm-project/issues/46029
[2]: https://cplusplus.github.io/CWG/issues/2421.html
Differential Revision: https://reviews.llvm.org/D120255
Bug #52905 was originally papered over in a different way, but
I believe this is the actually proper fix, or at least closer to
it. We need to detect placeholder types as close to the front-end
as possible, and cause them to fail constraints, rather than letting
them persist into later stages.
Fixes#52905.
Fixes#52909.
Fixes#53075.
Differential Revision: https://reviews.llvm.org/D118552
There is a special situation with templates in local classes,
as can be seen in this example with generic lambdas in function scope:
```
template<class T1> void foo() {
(void)[]<class T2>() {
struct S {
void bar() { (void)[]<class T3>(T2) {}; }
};
};
};
template void foo<int>();
```
As a consequence of the resolution of DR1484, bar is instantiated during the
substitution of foo, and in this context we would substitute the lambda within
it with it's own parameters "injected" (turned into arguments).
This can't be properly dealt with for at least a couple of reasons:
* The 'TemplateTypeParm' type itself can only deal with canonical replacement
types, which the injected arguments are not.
* If T3 were constrained in the example above, our (non-conforming) eager
substitution of type constraints would just leave that parameter dangling.
Instead of substituting with injected parameters, this patch just leaves those
inner levels unreplaced.
Since injected arguments appear to be unused within the users of
`getTemplateInstantiationArgs`, this patch just removes that support there and
leaves a couple of asserts in place.
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D110727
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
During template instantiation involving templated lambdas, clang
could hit an assertion in `TemplateDeclInstantiator::SubstFunctionType`
since the functions are not associated with any `TypeSourceInfo`:
`assert(OldTInfo && "substituting function without type source info");`
This path is triggered when using templated lambdas like the one added as
a test to this patch. To fix this:
- Create `TypeSourceInfo`s for special members and make sure the template
instantiator can get through all patterns.
- Introduce a `SpecialMemberTypeInfoRebuilder` tree transform to rewrite
such member function arguments. Without this, we get errors like:
`error: only special member functions and comparison operators may be defaulted`
since `getDefaultedFunctionKind` can't properly recognize these functions
as special members as part of `SetDeclDefaulted`.
Fixes PR45828 and PR44848
Differential Revision: https://reviews.llvm.org/D88327
This renames the expression value categories from rvalue to prvalue,
keeping nomenclature consistent with C++11 onwards.
C++ has the most complicated taxonomy here, and every other language
only uses a subset of it, so it's less confusing to use the C++ names
consistently, and mentally remap to the C names when working on that
context (prvalue -> rvalue, no xvalues, etc).
Renames:
* VK_RValue -> VK_PRValue
* Expr::isRValue -> Expr::isPRValue
* SK_QualificationConversionRValue -> SK_QualificationConversionPRValue
* JSON AST Dumper Expression nodes value category: "rvalue" -> "prvalue"
Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D103720
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
The idiom:
```
DeclContext::lookup_result R = DeclContext::lookup(Name);
for (auto *D : R) {...}
```
is not safe when in the loop body we trigger deserialization from an AST file.
The deserialization can insert new declarations in the StoredDeclsList whose
underlying type is a vector. When the vector decides to reallocate its storage
the pointer we hold becomes invalid.
This patch replaces a SmallVector with an singly-linked list. The current
approach stores a SmallVector<NamedDecl*, 4> which is around 8 pointers.
The linked list is 3, 5, or 7. We do better in terms of memory usage for small
cases (and worse in terms of locality -- the linked list entries won't be near
each other, but will be near their corresponding declarations, and we were going
to fetch those memory pages anyway). For larger cases: the vector uses a
doubling strategy for reallocation, so will generally be between half-full and
full. Let's say it's 75% full on average, so there's N * 4/3 + 4 pointers' worth
of space allocated currently and will be 2N pointers with the linked list. So we
break even when there are N=6 entries and slightly lose in terms of memory usage
after that. We suspect that's still a win on average.
Thanks to @rsmith!
Differential revision: https://reviews.llvm.org/D91524
Combined with 'da98651 - Revert "DR2064:
decltype(E) is only a dependent', this change (5a391d3) caused verifier
errors when building Chromium. See https://crbug.com/1168494#c1 for a
reproducer.
Additionally it reverts changes that were dependent on this one, see
below.
> Following up on PR48517, fix handling of template arguments that refer
> to dependent declarations.
>
> Treat an id-expression that names a local variable in a templated
> function as being instantiation-dependent.
>
> This addresses a language defect whereby a reference to a dependent
> declaration can be formed without any construct being value-dependent.
> Fixing that through value-dependence turns out to be problematic, so
> instead this patch takes the approach (proposed on the core reflector)
> of allowing the use of pointers or references to (but not values of)
> dependent declarations inside value-dependent expressions, and instead
> treating template arguments as dependent if they evaluate to a constant
> involving such dependent declarations.
>
> This ends up affecting a bunch of OpenMP tests, due to OpenMP
> imprecisely handling instantiation-dependent constructs, bailing out
> early instead of processing dependent constructs to the extent possible
> when handling the template.
>
> Previously committed as 8c1f2d15b8, and
> reverted because a dependency commit was reverted.
This reverts commit 5a391d38ac.
It also restores clang/test/SemaCXX/coroutines.cpp to its state before
da986511fb.
Revert "[c++20] P1907R1: Support for generalized non-type template arguments of scalar type."
> Previously committed as 9e08e51a20, and
> reverted because a dependency commit was reverted. This incorporates the
> following follow-on commits that were also reverted:
>
> 7e84aa1b81 by Simon Pilgrim
> ed13d8c667 by me
> 95c7b6cadb by Sam McCall
> 430d5d8429 by Dave Zarzycki
This reverts commit 4b574008ae.
Revert "[msabi] Mangle a template argument referring to array-to-pointer decay"
> [msabi] Mangle a template argument referring to array-to-pointer decay
> applied to an array the same as the array itself.
>
> This follows MS ABI, and corrects a regression from the implementation
> of generalized non-type template parameters, where we "forgot" how to
> mangle this case.
This reverts commit 18e093faf7.
This was already done in SemaTemplateInstantiateDecl.cpp, but not in
SemaTemplateInstantiate.cpp.
Anecdotally I've seen some clangd crashes where coredumps point to this
being a problem, but I cannot reproduce this so far.
Differential Revision: https://reviews.llvm.org/D94933
Previously committed as 9e08e51a20, and
reverted because a dependency commit was reverted. This incorporates the
following follow-on commits that were also reverted:
7e84aa1b81 by Simon Pilgrim
ed13d8c667 by me
95c7b6cadb by Sam McCall
430d5d8429 by Dave Zarzycki
to dependent declarations.
Treat an id-expression that names a local variable in a templated
function as being instantiation-dependent.
This addresses a language defect whereby a reference to a dependent
declaration can be formed without any construct being value-dependent.
Fixing that through value-dependence turns out to be problematic, so
instead this patch takes the approach (proposed on the core reflector)
of allowing the use of pointers or references to (but not values of)
dependent declarations inside value-dependent expressions, and instead
treating template arguments as dependent if they evaluate to a constant
involving such dependent declarations.
This ends up affecting a bunch of OpenMP tests, due to OpenMP
imprecisely handling instantiation-dependent constructs, bailing out
early instead of processing dependent constructs to the extent possible
when handling the template.
Previously committed as 8c1f2d15b8, and
reverted because a dependency commit was reverted.
Some clients which want to track state need the information whether a template
was instantiated and made invalid.
Differential revision: https://reviews.llvm.org/D92248
Matheus Izvekov