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).
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Resubmit after fixing MSAN failures caused by incomplete initialization of AutoTypeLocs in TypeSpecLocFiller.
Differential Revision: https://reviews.llvm.org/D65042
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Resubmit after incorrect check in NonTypeTemplateParmDecl broke lldb.
Differential Revision: https://reviews.llvm.org/D65042
This patch implements P1141R2 "Yet another approach for constrained declarations".
General strategy for this patch was:
- Expand AutoType to include optional type-constraint, reflecting the wording and easing the integration of constraints.
- Replace autos in parameter type specifiers with invented parameters in GetTypeSpecTypeForDeclarator, using the same logic
previously used for generic lambdas, now unified with abbreviated templates, by:
- Tracking the template parameter lists in the Declarator object
- Tracking the template parameter depth before parsing function declarators (at which point we can match template
parameters against scope specifiers to know if we have an explicit template parameter list to append invented parameters
to or not).
- When encountering an AutoType in a parameter context we check a stack of InventedTemplateParameterInfo structures that
contain the info required to create and accumulate invented template parameters (fields that were already present in
LambdaScopeInfo, which now inherits from this class and is looked up when an auto is encountered in a lambda context).
Differential Revision: https://reviews.llvm.org/D65042
expanded by the deduced pack.
We recently started also deducing the arity of separately-expanded packs
that are merely mentioned within the pack in question, which is
incorrect.
Add support for type-constraints in template type parameters.
Also add support for template type parameters as pack expansions (where the type constraint can now contain an unexpanded parameter pack).
Differential Revision: https://reviews.llvm.org/D44352
D41910 introduced a recursive visitor to MarkUsedTemplateParameters, but
disregarded the 'Depth' parameter, and had incorrect assertions. This fixes
the visitor and removes the assertions.
Function trailing requires clauses now parsed, supported in overload resolution and when calling, referencing and taking the address of functions or function templates.
Differential Revision: https://reviews.llvm.org/D43357
pack expansion.
Previously, if all parameter / argument pairs for a pack expansion
deduction were non-deduced contexts, we would not deduce the arity of
the pack, and could end up deducing a different arity (leading to
failures during substitution) or defaulting to an arity of 0 (leading to
bad diagnostics about passing the wrong number of arguments to a
variadic function). Instead, we now always deduce the arity for all
involved packs any time we deduce a pack expansion.
This will result in less substitution happening in some cases, which
could avoid non-SFINAEable errors, and should generally improve the
quality of diagnostics when passing initializer lists to variadic
functions.
Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Re-commit after fixing another crash (added regression test).
Differential Revision: https://reviews.llvm.org/D41910
Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Re-commit after fixing some crashes and warnings.
Differential Revision: https://reviews.llvm.org/D41910
Added support for constraint satisfaction checking and partial ordering of constraints in constrained partial specialization and function template overloads.
Phabricator: D41910
Part of the C++20 concepts implementation effort.
- Associated constraints (requires clauses, currently) are now enforced when instantiating/specializing templates and when considering partial specializations and function overloads.
- Elaborated diagnostics give helpful insight as to why the constraints were not satisfied.
Phabricator: D41569
Re-commit, after fixing some memory bugs.
Part of the C++20 concepts implementation effort.
- Associated constraints (requires clauses, currently) are now enforced when instantiating/specializing templates and when considering partial specializations and function overloads.
- Elaborated diagnostics give helpful insight as to why the constraints were not satisfied.
Phabricator: D41569
The static analyzer is warning about potential null dereferences, but in these cases we should be able to use castAs<> directly and if not assert will fire for us.
llvm-svn: 375443
Summary:
- Even though only `void` is still accepted as the deduced return type,
enabling deduction/instantiation on the return type allows more
consistent coding.
Reviewers: tra, jlebar
Subscribers: cfe-commits, yaxunl
Tags: #clang
Differential Revision: https://reviews.llvm.org/D68031
llvm-svn: 372898
containing designators. The C++20 wording doesn't actually say what
happens in this case, but treating this as a non-deduced context seems
like the most natural behavior.
(We might want to consider deducing through array designators as an
extension in the future, but will need to be careful to deduce the array
bound properly if we do so. That's not permitted herein.)
llvm-svn: 370555
Summary:
Clang performs various recursive operations (such as template instantiation),
and may use non-trivial amounts of stack space in each recursive step (for
instance, due to recursive AST walks). While we try to keep the stack space
used by such steps to a minimum and we have explicit limits on the number of
such steps we perform, it's impractical to guarantee that we won't blow out the
stack on deeply recursive template instantiations on complex ASTs, even with
only a moderately high instantiation depth limit.
The user experience in these cases is generally terrible: we crash with
no hint of what went wrong. Under this patch, we attempt to do better:
* Detect when the stack is nearly exhausted, and produce a warning with a
nice template instantiation backtrace, telling the user that we might
run slowly or crash.
* For cases where we're forced to trigger recursive template
instantiation in arbitrarily-deeply-nested contexts, check whether
we're nearly out of stack space and allocate a new stack (by spawning
a new thread) after producing the warning.
Reviewers: rnk, aaron.ballman
Subscribers: mgorny, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D66361
llvm-svn: 369940
This permits an init-capture to introduce a new pack:
template<typename ...T> auto x = [...a = T()] { /* a is a pack */ };
To support this, the mechanism for allowing ParmVarDecls to be packs has
been extended to support arbitrary local VarDecls.
llvm-svn: 361300
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
placeholder expressions while an unevaluated context is still on the
expression evaluation context stack.
This prevents recordUseOfWeek from being called when a weak variable is
used as an operand of a decltype or a typeof expression and fixes
spurious -Warc-repeated-use-of-weak warnings.
rdar://problem/45742525
Differential Revision: https://reviews.llvm.org/D55662
llvm-svn: 350887
Address spaces are cast into generic before invoking the constructor.
Added support for a trailing Qualifiers object in FunctionProtoType.
Note: This recommits the previously reverted patch,
but now it is commited together with a fix for lldb.
Differential Revision: https://reviews.llvm.org/D54862
llvm-svn: 349019
Address spaces are cast into generic before invoking the constructor.
Added support for a trailing Qualifiers object in FunctionProtoType.
Differential Revision: https://reviews.llvm.org/D54862
llvm-svn: 348927
It seems the two failing tests can be simply fixed after r348037
Fix 3 cases in Analysis/builtin-functions.cpp
Delete the bad CodeGen/builtin-constant-p.c for now
llvm-svn: 348053
Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:
extern char extern_var;
struct { int a; } a = {__builtin_constant_p(extern_var)};
llvm-svn: 348039
This was reverted in r347656 due to me thinking it caused a miscompile of
Chromium. Turns out it was the Chromium code that was broken.
llvm-svn: 347756
This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:
static bool f(int *a, int *b) {
return !__builtin_constant_p(b - a) || (!(b - a));
}
int arr[] = {1,2,3};
bool g() {
return f(arr, arr + 3);
}
$ clang -O2 -S -emit-llvm a.cc -o -
g() should return true, but after r347417 it became false for some reason.
This also reverts the follow-up commits.
r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!
r347446:
> The result of is.constant() is unsigned.
r347480:
> A __builtin_constant_p() returns 0 with a function type.
r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.
r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.
llvm-svn: 347656
Summary:
A __builtin_constant_p may end up with a constant after inlining. Use
the is.constant intrinsic if it's a variable that's in a context where
it may resolve to a constant, e.g., an argument to a function after
inlining.
Reviewers: rsmith, shafik
Subscribers: jfb, kristina, cfe-commits, nickdesaulniers, jyknight
Differential Revision: https://reviews.llvm.org/D54355
llvm-svn: 347294
provided by an outer template.
We made the incorrect assumption in various places that the only way we
can have any arguments already provided for a pack during template
argument deduction was from a partially-specified pack. That's not true;
we can also have arguments from an enclosing already-instantiated
template, and that can even result in the function template's own pack
parameters having a fixed length and not being packs for the purposes of
template argument deduction.
llvm-svn: 337481
As listed in the above PRs, vector_size doesn't allow
dependent types/values. This patch introduces a new
DependentVectorType to handle a VectorType that has a dependent
size or type.
In the future, ALL the vector-types should be able to create one
of these to handle dependent types/sizes as well. For example,
DependentSizedExtVectorType could likely be switched to just use
this instead, though that is left as an exercise for the future.
Differential Revision: https://reviews.llvm.org/D49045
llvm-svn: 337036
function parameter packs.
This makes our handling of non-trailing function parameter packs
consistent between the case of deduction at the top level in a function
call and other cases where deduction encounters a non-trailing function
parameter pack.
Instead of treating a non-trailing pack and all later parameters as
being non-deduced, we treat a non-trailing pack as exactly matching
any explicitly-specified template arguments (or being an empty pack
if there are no such arguments). This corresponds to the "never deduced"
rule in [temp.deduct.call]p1, but generalized to all deduction contexts.
Non-trailing template argument packs still result in the entire
template argument list being treated as non-deduced, as specified in
[temp.deduct.type]p9.
llvm-svn: 336962
Richard Smith