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 8c1f2d15b826591cdf6bd6b468b8a7d23377b29e, and
> reverted because a dependency commit was reverted.
This reverts commit 5a391d38ac6c561ba908334d427f26124ed9132e.
It also restores clang/test/SemaCXX/coroutines.cpp to its state before
da986511fb9da1a46a0ca4dba2e49e2426036303.
Revert "[c++20] P1907R1: Support for generalized non-type template arguments of scalar type."
> Previously committed as 9e08e51a20d0d2b1c5724bb17e969d036fced4cd, and
> reverted because a dependency commit was reverted. This incorporates the
> following follow-on commits that were also reverted:
>
> 7e84aa1b81e72d44bcc58ffe1731bfc7abb73ce0 by Simon Pilgrim
> ed13d8c66781b50ff007cb089c5905f9bb9e8af2 by me
> 95c7b6cadbc9a3d4376ef44edbeb3c8bb5b8d7fc by Sam McCall
> 430d5d8429473c2b10b109991d7577a3cea41140 by Dave Zarzycki
This reverts commit 4b574008aef5a7235c1f894ab065fe300d26e786.
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 18e093faf726d15f210ab4917142beec51848258.
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 9e08e51a20d0d2b1c5724bb17e969d036fced4cd, and
reverted because a dependency commit was reverted. This incorporates the
following follow-on commits that were also reverted:
7e84aa1b81e72d44bcc58ffe1731bfc7abb73ce0 by Simon Pilgrim
ed13d8c66781b50ff007cb089c5905f9bb9e8af2 by me
95c7b6cadbc9a3d4376ef44edbeb3c8bb5b8d7fc by Sam McCall
430d5d8429473c2b10b109991d7577a3cea41140 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 8c1f2d15b826591cdf6bd6b468b8a7d23377b29e, 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
This reverts commit 8c1f2d15b826591cdf6bd6b468b8a7d23377b29e.
This is part of 5 commits being reverted due to https://crbug.com/1161059. See bug for repro.
This reverts commit 9e08e51a20d0d2b1c5724bb17e969d036fced4cd.
This is part of 5 commits being reverted due to https://crbug.com/1161059. See bug for repro.
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.
after destroying an InstantiatingTemplate object.
This previously caused us to (silently!) bail out of class template
instantiation, thinking we'd produced an error, in some corner cases.
This requires that we track enough information to determine the original
type of the parameter in a substituted non-type template parameter, to
distinguish the reference-to-class case from the class case.
when instantiating the enclosing class.
We'll build new lambda closure types if and when we instantiate the
default member initializer, and instantiating the closure type by itself
can go wrong in cases where we fully-instantiate nested classes (in
explicit instantiations of the enclosing class and when the enclosing
class is a local class) -- we will instantiate the 'operator()' as a
regular function rather than as a lambda call operator, so it doesn't
get to use its captures, has the wrong 'this' type, etc.
This recommits 7f1f89ec8d9944559042bb6d3b1132eabe3409de and
40df06cdafc010002fc9cfe1dda73d689b7d27a6 with bug fixes for
memory sanitizer failure and Tensile build failure.
This changes some diagnostics to use terminology from the standard
rather than invented terminology, which improves consistency with other
diagnostics as well. There are no functional changes intended other
than wording and naming.
In CUDA/HIP a function may become implicit host device function by
pragma or constexpr. A host device function is checked in both
host and device compilation. However it may be emitted only
on host or device side, therefore the diagnostics should be
deferred until it is known to be emitted.
Currently clang is only able to defer certain diagnostics. This causes
false alarms and limits the usefulness of host device functions.
This patch lets clang defer all overloading resolution diagnostics for host device functions.
An option -fgpu-defer-diag is added to control this behavior. By default
it is off.
It is NFC for other languages.
Differential Revision: https://reviews.llvm.org/D84364
lambda when instantiating a call operator specialization.
We previously incorrectly thought that such substitution was happening
in the context of substitution into a local scope, which is a context
where we should perform eager default argument instantiation.
specializations and those that are done as part of rewrites.
Do not create Subst* nodes in the latter. We previously had a hybrid of
these two behaviors where we would only create some Subst* nodes but not
others during deduction guide rewrites.
No functional change intended, but the resulting ASTs are more
principled.
As reported in PR46111, implicit instantiation of a deduction guide
causes us to have an elaborated type as the parameter, rather than the
dependent type.
After review and feedback from @rsmith, this patch solves this problem
by wrapping the value in an uninstantiated typedef/type-alias that is
instantiated when required later.
Differential Revision: https://reviews.llvm.org/D80743
...before checking that the default argument is valid with
CheckDefaultArgumentVisitor.
Currently the restrictions on a default argument are checked with the visitor
CheckDefaultArgumentVisitor in ActOnParamDefaultArgument before
performing the conversion to the parameter type in SetParamDefaultArgument.
This was fine before the previous patch but now some valid code post-CWG 2346
is rejected:
void test() {
const int i2 = 0;
extern void h2a(int x = i2); // FIXME: ok, not odr-use
extern void h2b(int x = i2 + 0); // ok, not odr-use
}
This is because the reference to i2 in h2a has not been marked yet with
NOUR_Constant. i2 is marked NOUR_Constant when the conversion to the parameter
type is done, which is done just after.
The solution is to do the conversion to the parameter type before checking
the restrictions on default arguments with CheckDefaultArgumentVisitor.
This has the side-benefit of improving some diagnostics.
Differential Revision: https://reviews.llvm.org/D81616
Reviewed By: rsmith
DiagnosticErrorTrap is usually inappropriate because it indicates
whether an error message was rendered in a given region (and is
therefore affected by -ferror-limit and by suppression of errors if we
see an invalid declaration).
hasErrorOccurred() is usually inappropriate because it indicates
whethere an "error:" message was displayed, regardless of whether the
message was a warning promoted to an error, and therefore depends on
things like -Werror that are usually irrelevant.
Where applicable, CodeSynthesisContexts are used to attach notes to
the first diagnostic produced in a region of code, isnstead of using an
error trap and then attaching a note to whichever diagnostic happened to
be produced last (or suppressing the note if the final diagnostic is a
disabled warning!).
This is mostly NFC.
parameters with default arguments.
Directly follow the wording by relaxing the AST invariant that all
parameters after one with a default arguemnt also have default
arguments, and removing the diagnostic on missing default arguments
on a pack-expanded parameter following a parameter with a default
argument.
Testing also revealed that we need to special-case explicit
specializations of templates with a pack following a parameter with a
default argument, as such explicit specializations are otherwise
impossible to write. The standard wording doesn't address this case; a
issue has been filed.
This exposed a bug where we would briefly consider a parameter to have
no default argument while we parse a delay-parsed default argument for
that parameter, which is also fixed.
Partially incorporates a patch by Raul Tambre.
Summary:
We extend the behavior for local functions and methods of local classes
to lambdas in variable initializers. The initializer is not a separate
scope, but we treat it as such.
We also remove the (faulty) instantiation of default arguments in
TreeTransform::TransformLambdaExpr, because it doesn't do proper
initialization, and if it did, we would do it twice (and thus also emit
eventual errors twice).
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D76038
In order to support non-user-named kernels, SYCL needs some way in the
integration headers to name the kernel object themselves. Initially, the
design considered just RTTI naming of the lambdas, this results in a
quite unstable situation in light of some device/host macros.
Additionally, this ends up needing to use RTTI, which is a burden on the
implementation and typically unsupported.
Instead, we've introduced a builtin, __builtin_unique_stable_name, which
takes a type or expression, and results in a constexpr constant
character array that uniquely represents the type (or type of the
expression) being passed to it.
The implementation accomplishes that simply by using a slightly modified
version of the Itanium Mangling. The one exception is when mangling
lambdas, instead of appending the index of the lambda in the function,
it appends the macro-expansion back-trace of the lambda itself in the
form LINE->COL[~LINE->COL...].
Differential Revision: https://reviews.llvm.org/D76620
a dependent context.
This matches the GCC behavior.
We track the enclosing template depth when determining whether a
statement expression is within a dependent context; there doesn't appear
to be any other reliable way to determine this.
We previously assumed they were neither value- nor
instantiation-dependent under any circumstances, which would lead to
crashes and other misbehavior.
GetContainedInventedTypeParmVisitor would not account for the case where TemplateTypeParmType::getDecl() is
nullptr, causing bug #45102.
Add the nullptr check.
We would incorrectly check whether the type-constraint had already been initialized, causing us
to ignore the invented template type constraints entirely.
Also, TemplateParameterList would store incorrect information about invented type parameters
when it observed them before their type-constraint was initialized, so we recreate it after
initializing the function type of an abbreviated template.
We previously instantiated type-constraints of template type parameters along with the type parameter itself,
this caused problems when the type-constraints created by abbreviated templates refreneced other parameters
in the abbreviated templates.
When encountering a template type parameter with a type constraint, if it is implicit, delay instantiation of
the type-constraint until the function parameter which created the invented template type parameter is
instantiated.
Reland after fixing bug caused by another flow reaching SubstParmVarDecl and instantiating the TypeConstraint
a second time.
We previously instantiated type-constraints of template type parameters along with the type parameter itself,
this caused problems when the type-constraints created by abbreviated templates refreneced other parameters
in the abbreviated templates.
When encountering a template type parameter with a type constraint, if it is implicit, delay instantiation of
the type-constraint until the function parameter which created the invented template type parameter is
instantiated.
We previously would not correctly for the initial parameter mapping for variadic template parameters in Concepts.
Testing this lead to the discovery that with the normalization process we would need to substitute into already-substituted-into
template arguments, which means we need to add NonTypeTemplateParmExpr support to TemplateInstantiator.
We do that by substituting into the replacement and the type separately, and then re-checking the expression against the NTTP
with the new type, in order to form any new required implicit casts (for cases where the type of the NTTP was dependent).
We would previously try to evaluate atomic constraints of non-template functions as-is,
and since they are now unevaluated at first, this would cause incorrect evaluation (bugs #44657, #44656).
Substitute into atomic constraints of non-template functions as we would atomic constraints
of template functions, in order to rebuild the expressions in a constant-evaluated context.
