Commit Graph

1471 Commits

Author SHA1 Message Date
Saar Raz e57a9abc4b [Concepts] Placeholder constraints and abbreviated templates
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
2020-01-22 12:09:13 +02:00
Saar Raz 45538b5fb2 [Concepts] Fix bug when referencing function parameters in instantiated function template requires clause
Fixes bug #44613 - instantiated parameters were not being added when instantiating the requires clauses.
2020-01-22 11:25:27 +02:00
Jonas Devlieghere 62e4b501ab Revert "[Concepts] Placeholder constraints and abbreviated templates"
This temporarily reverts commit e03ead6771
because it breaks LLDB.

http://lab.llvm.org:8011/builders/lldb-x86_64-debian/builds/3356
http://lab.llvm.org:8011/builders/lldb-x64-windows-ninja/builds/12872
http://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/6407/
2020-01-21 19:03:52 -08:00
Saar Raz b933d37cd3 [Concepts] Constraint Satisfaction Caching
Add a simple cache for constraint satisfaction results. Whether or not this simple caching
would be permitted in final C++2a is currently being discussed but it is required for
acceptable performance so we use it in the meantime, with the possibility of adding some
cache invalidation mechanisms later.

Differential Revision: https://reviews.llvm.org/D72552
2020-01-22 03:09:53 +02:00
Saar Raz e03ead6771 [Concepts] Placeholder constraints and abbreviated templates
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
2020-01-22 02:03:05 +02:00
Richard Smith 13fa4e2e5a PR42108 Consistently diagnose binding a reference template parameter to
a temporary.

We previously failed to materialize a temporary when performing an
implicit conversion to a reference type, resulting in our thinking the
argument was a value rather than a reference in some cases.
2020-01-19 18:16:36 -08:00
Saar Raz a0f50d7316 [Concepts] Requires Expressions
Implement support for C++2a requires-expressions.

Re-commit after compilation failure on some platforms due to alignment issues with PointerIntPair.

Differential Revision: https://reviews.llvm.org/D50360
2020-01-19 00:23:26 +02:00
Saar Raz baa84d8cde Revert "[Concepts] Requires Expressions"
This reverts commit 0279318997.

There have been some failing tests on some platforms, reverting while investigating.
2020-01-18 14:58:01 +02:00
Saar Raz 0279318997 [Concepts] Requires Expressions
Implement support for C++2a requires-expressions.

Differential Revision: https://reviews.llvm.org/D50360
2020-01-18 09:15:36 +02:00
Richard Smith a42fd84cff Remove redundant CXXScopeSpec from TemplateIdAnnotation.
A TemplateIdAnnotation represents only a template-id, not a
nested-name-specifier plus a template-id. Don't make a redundant copy of
the CXXScopeSpec and store it on the template-id annotation.

This slightly improves error recovery by more properly handling the case
where we would form an invalid CXXScopeSpec while parsing a typename
specifier, instead of accidentally putting the token stream into a
broken "annot_template_id with a scope specifier, but with no preceding
annot_cxxscope token" state.
2020-01-17 15:47:21 -08:00
Richard Smith e8f198dd9e Fix pack deduction to only deduce the arity of packs that are actually
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.
2020-01-15 16:21:08 -08:00
Saar Raz ff1e0fce81 [Concepts] Type Constraints
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
2020-01-15 04:02:39 +02:00
Saar Raz b65b1f322b [Concepts] Function trailing requires clauses
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
2020-01-09 15:07:51 +02:00
Richard Smith 907cefe721 Always deduce the lengths of contained parameter packs when deducing a
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.
2020-01-06 17:24:29 -08:00
Amy Huang a85f5efd95 Add support for the MS qualifiers __ptr32, __ptr64, __sptr, __uptr.
Summary:
This adds parsing of the qualifiers __ptr32, __ptr64, __sptr, and __uptr and
lowers them to the corresponding address space pointer for 32-bit and 64-bit pointers.
(32/64-bit pointers added in https://reviews.llvm.org/D69639)

A large part of this patch is making these pointers ignore the address space
when doing things like overloading and casting.

https://bugs.llvm.org/show_bug.cgi?id=42359

Reviewers: rnk, rsmith

Subscribers: jholewinski, jvesely, nhaehnle, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D71039
2019-12-18 10:41:12 -08:00
Eric Christopher 259a9b1039 Update line number after previous patch added an additional unsupported
and comment lines.
2019-12-12 14:45:05 -08:00
Michał Górny 4c6c1d0f43 [clang] [test] Disable the test exhausting stack on NetBSD
Disable the instantiation-depth-default.cpp test on NetBSD since it
requires more stack space than we have by default on NetBSD.

Differential Revision: https://reviews.llvm.org/D71419
2019-12-12 22:23:20 +01:00
Richard Smith b220662a45 Properly convert all declaration non-type template arguments when
forming non-type template parameter values.

This reverts commit 93cc9dddd8,
which reverted commit 11d1052785.

We now always form `&x` when forming a pointer to a function rather than
trying to use function-to-pointer decay. This matches the behavior of
the old code in this case, but not the intent as described by the
comments.
2019-12-05 14:32:36 -08:00
David L. Jones 93cc9dddd8 Revert "Properly convert all declaration non-type template arguments when"
This reverts commit 11d1052785.

This change is problematic with function pointer template parameters. For
example, building libcxxabi with futexes (-D_LIBCXXABI_USE_FUTEX) produces this
diagnostic:

    In file included from .../llvm-project/libcxxabi/src/cxa_guard.cpp:15:
    .../llvm-project/libcxxabi/src/cxa_guard_impl.h:416:54: error: address of function 'PlatformThreadID' will always evaluate to 'true' [-Werror,-Wpointer-bool-conversion]
        has_thread_id_support(this->thread_id_address && GetThreadIDArg),
                                                      ~~ ^~~~~~~~~~~~~~
    .../llvm-project/libcxxabi/src/cxa_guard.cpp:38:26: note: in instantiation of member function '__cxxabiv1::(anonymous namespace)::InitByteFutex<&__cxxabiv1::(anonymous namespace)::PlatformFutexWait, &__cxxabiv1::(anonymous namespace)::PlatformFutexWake, &__cxxabiv1::(anonymous namespace)::PlatformThreadID>::InitByteFutex' requested here
      SelectedImplementation imp(raw_guard_object);
                             ^
    .../llvm-project/libcxxabi/src/cxa_guard_impl.h:416:54: note: prefix with the address-of operator to silence this warning
        has_thread_id_support(this->thread_id_address && GetThreadIDArg),
                                                         ^
                                                         &
    1 error generated.

The diagnostic is incorrect: adding the address-of operator also fails ("cannot
take the address of an rvalue of type 'uint32_t (*)()' (aka 'unsigned int
(*)()')").
2019-12-04 22:12:15 -08:00
Richard Smith 11d1052785 Properly convert all declaration non-type template arguments when
forming non-type template parameter values.
2019-12-04 18:55:24 -08:00
Richard Smith a1d2611c04 [c++17] Fix assert / wrong code when passing a noexcept pointer to
member function to a non-noexcept pointer to member non-type template
parameter.
2019-12-04 18:55:23 -08:00
Elizabeth Andrews 878a24ee24 Reapply "Fix crash on switch conditions of non-integer types in templates"
This patch reapplies commit 759948467e. Patch was reverted due to a
clang-tidy test fail on Windows. The test has been modified. There
are no additional code changes.

Patch was tested with ninja check-all on Windows and Linux.

Summary of code changes:

Clang currently crashes for switch statements inside a template when the
condition is a non-integer field member because contextual implicit
conversion is skipped when parsing the condition. This conversion is
however later checked in an assert when the case statement is handled.
The conversion is skipped when parsing the condition because
the field member is set as type-dependent based on its containing class.
This patch sets the type dependency based on the field's type instead.

This patch fixes Bug 40982.
2019-12-03 15:27:19 -08:00
Dávid Bolvanský 1da13237a4 [Diagnostics] Try to improve warning message for -Wreturn-type
Summary: I agree with https://easyaspi314.github.io/gcc-vs-clang.html?fbclid=IwAR1VA0qxiWVUusOQUv5z7JESS7ZpeJy-UqAI5mnJscofGLqXcqeErIUB2gU, current warning message is not very good. We should try to improve it..

Reviewers: rsmith, aaron.ballman, easyaspi314

Reviewed By: aaron.ballman

Subscribers: arphaman, Quuxplusone, mehdi_amini, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D69762
2019-11-09 17:54:58 +01:00
Melanie Blower d0b3e73175 Revert "Reapply "Fix crash on switch conditions of non-integer types in templates""
This reverts commit 759948467e.
There were build bot failures in clang-tidy
2019-11-08 14:18:15 -08:00
Melanie Blower 759948467e Reapply "Fix crash on switch conditions of non-integer types in templates"
This patch reapplies commit 76945821b9. The first version broke
buildbots due to clang-tidy test fails. The fails are because some
errors in templates are now diagnosed earlier (does not wait till
instantiation). I have modified the tests to add checks for these
diagnostics/prevent these diagnostics. There are no additional code
changes.

Summary of code changes:

Clang currently crashes for switch statements inside a template when the
condition is a non-integer field member because contextual implicit
conversion is skipped when parsing the condition. This conversion is
however later checked in an assert when the case statement is handled.
The conversion is skipped when parsing the condition because
the field member is set as type-dependent based on its containing class.
This patch sets the type dependency based on the field's type instead.

This patch fixes Bug 40982.

Reviewers: rnk, gribozavr2

Patch by: Elizabeth Andrews (eandrews)

Differential revision: https://reviews.llvm.org/D69950
2019-11-08 10:17:06 -08:00
Mark de Wever 2b943c4687 [Sema] Fixes a crash with a templated destructor
The issue was introduced by D33189 which fixed PR33189.

Fixes PR38671: "destructor cannot be declared as a template" leads to segfault in Sema::LookupSpecialMember

Differential Revision: https://reviews.llvm.org/D69225
2019-11-07 21:22:27 +01:00
Dávid Bolvanský 55507110b9 [Diagnostics] Improve some error messages related to bad use of dynamic_cast 2019-11-04 16:26:43 +01:00
Richard Smith 06d3fce01d PR43400: Add test that we can instantiate a friend function that is
defined as deleted.

The actual bug was fixed in commit d052a578.
2019-10-27 12:41:53 -07:00
Richard Smith 70f59b5bbc When diagnosing an ambiguity, only note the candidates that contribute
to the ambiguity, rather than noting all viable candidates.
2019-10-24 14:58:29 -07:00
Richard Smith 9d1eba184e Fix assertion failure for a cv-qualified array as a non-type template
parameter type.

We were both failing to decay the array type to a pointer and failing to
remove the top-level cv-qualifications. Fix this by decaying array
parameters even if the parameter type is dependent.

llvm-svn: 374496
2019-10-11 01:29:53 +00:00
Richard Smith 772e266fbf Properly handle instantiation-dependent array bounds.
We previously failed to treat an array with an instantiation-dependent
but not value-dependent bound as being an instantiation-dependent type.
We now track the array bound expression as part of a constant array type
if it's an instantiation-dependent expression.

llvm-svn: 373685
2019-10-04 01:25:59 +00:00
Richard Smith 5d96b4ce28 Check for qualified function types after substituting into the operand
of 'typeid'.

This is a rare place where it's valid for a function type to be
substituted but not valid for a qualified function type to be
substituted, so needs a special check.

llvm-svn: 373648
2019-10-03 18:55:23 +00:00
Richard Smith 8d2eaf9239 PR43547: substitute into the type of a non-type template parameter if
it's instantiation-dependent, even if it's not dependent.

There might be a SFINAE check in the parameter type.

llvm-svn: 373643
2019-10-03 18:24:40 +00:00
Richard Smith bf322b7cdd Always rebuild a DeclRefExpr if its FoundDecl would change.
Fixes a regression introduced by r369999.

llvm-svn: 373022
2019-09-26 22:28:32 +00:00
Nicholas Allegra cbd13bc1ed Push lambda scope earlier when transforming lambda expression
Differential Revision: https://reviews.llvm.org/D66067

llvm-svn: 372058
2019-09-17 01:43:33 +00:00
Aaron Ballman c4450437ec Fixes an assertion while instantiating a template with an incomplete typo-corrected type.
Fixes PR35682. When a template in instantiated with an incomplete typo corrected type an assertion can trigger if the -ferror-limit is used to reduce the number of errors.

Patch by Mark de Wever.

llvm-svn: 371320
2019-09-07 20:14:09 +00:00
Richard Smith 03c13e5718 Disable stack exhaustion test on NetBSD, where either the detection or
recovery mechanism does not appear to work.

llvm-svn: 370801
2019-09-03 18:00:44 +00:00
Richard Smith 082754176f [c++20] Disallow template argument deduction from a braced-init-list
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
2019-08-31 00:05:50 +00:00
Richard Smith 5030928d60 [c++20] Implement semantic restrictions for C++20 designated
initializers.

This has some interesting interactions with our existing extensions to
support C99 designated initializers as an extension in C++. Those are
resolved as follows:

 * We continue to permit the full breadth of C99 designated initializers
   in C++, with the exception that we disallow a partial overwrite of an
   initializer with a non-trivially-destructible type. (Full overwrite
   is OK, because we won't run the first initializer at all.)

 * The C99 extensions are disallowed in SFINAE contexts and during
   overload resolution, where they could change the meaning of valid
   programs.

 * C++20 disallows reordering of initializers. We only check for that for
   the simple cases that the C++20 rules permit (designators of the form
   '.field_name =' and continue to allow reordering in other cases).
   It would be nice to improve this behavior in future.

 * All C99 designated initializer extensions produce a warning by
   default in C++20 mode. People are going to learn the C++ rules based
   on what Clang diagnoses, so it's important we diagnose these properly
   by default.

 * In C++ <= 17, we apply the C++20 rules rather than the C99 rules, and
   so still diagnose C99 extensions as described above. We continue to
   accept designated C++20-compatible initializers in C++ <= 17 silently
   by default (but naturally still reject under -pedantic-errors).

This is not a complete implementation of P0329R4. In particular, that
paper introduces new non-C99-compatible syntax { .field { init } }, and
we do not support that yet.

This is based on a previous patch by Don Hinton, though I've made
substantial changes when addressing the above interactions.

Differential Revision: https://reviews.llvm.org/D59754

llvm-svn: 370544
2019-08-30 22:52:55 +00:00
Richard Smith 26a92d5852 Improve behavior in the case of stack exhaustion.
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
2019-08-26 18:18:07 +00:00
Richard Smith cb167c85b4 PR42513: Enter the proper DeclContext before substituting into an
default template argument expression.

We already did this for type template parameters and template template
parameters, but apparently forgot to do so for non-type template
parameters. This causes the substituted default argument expression to
be substituted in the proper context, and in particular to properly mark
its subexpressions as odr-used.

llvm-svn: 369834
2019-08-24 02:30:00 +00:00
Dmitri Gribenko a5ef73cb4b Revert "Fix crash on switch conditions of non-integer types in templates"
This reverts commit r368706. It broke ClangTidy tests.

llvm-svn: 368738
2019-08-13 19:07:28 +00:00
Elizabeth Andrews 76945821b9 Fix crash on switch conditions of non-integer types in templates
Clang currently crashes for switch statements inside a template when
the condition is a non-integer field. The crash is due to incorrect
type-dependency of field. Type-dependency of member expressions is
currently set based on the containing class. This patch changes this for
'members of the current instantiation' to set the type dependency based
on the member's type instead.

A few lit tests started to fail once I applied this patch because errors
are now diagnosed earlier (does not wait till instantiation). I've modified
these tests in this patch as well.

Patch fixes PR#40982

Differential Revision: https://reviews.llvm.org/D61027

llvm-svn: 368706
2019-08-13 15:53:19 +00:00
Sunil Srivastava 85d667fcb6 Renamed and changed the wording of warn_cconv_ignored
As discussed in D64780 the wording of this warning message is being
changed to say 'is not supported' instead of 'ignored', and the
diag ID itself is being changed to warn_cconv_not_supported.

llvm-svn: 366368
2019-07-17 20:41:26 +00:00
Sam McCall 0afffab0d1 [SemaTemplate] Fix uncorrected typos after pack expansion
Summary:
This case is particularly important for clangd, as it is triggered after
inserting the snippet for variadic functions.

Reviewers: kadircet, ilya-biryukov

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64677

llvm-svn: 366200
2019-07-16 10:30:21 +00:00
Richard Smith 30519a68d5 Add regression test for PR41576 (which is already fixed in trunk,
perhaps by r361300).

llvm-svn: 364340
2019-06-25 18:42:53 +00:00
Richard Smith 9771f500f2 PR42362: Fix auto deduction of template parameter packs from
type-dependent argument packs.

We need to strip off the PackExpansionExpr to get the real (dependent)
type rather than an opaque DependentTy.

llvm-svn: 364165
2019-06-24 05:53:11 +00:00
Richard Smith 07ed9cfc3e Fix crash and rejects-valid when a later template parameter or default
template argument contains a backreference to a dependently-typed
earlier parameter.

In a case like:
  template<typename T, T A, decltype(A) = A> struct X {};
  template<typename U> auto Y = X<U, 0>();
we previously treated both references to `A` in the third parameter as
being of type `int` when checking the template-id in `Y`. That`s wrong;
the type of `A` in these contexts is the dependent type `U`.

When we encounter a non-type template argument that we can't convert to
the parameter type because of type-dependence, we now insert a dependent
conversion node so that the SubstNonTypeTemplateParmExpr for the
template argument will have the parameter's type rather than whatever
type the argument had.

llvm-svn: 363972
2019-06-20 19:49:13 +00:00
Richard Smith 94bc88ebf4 Fix crash when checking a dependently-typed reference that is
initialized from a non-value-dependent initializer.

llvm-svn: 363622
2019-06-17 21:46:17 +00:00
Richard Smith 7f61d44178 Mark declarations as referenced by a default argument in a
potentially-evaluated context.

This applies even if the use of the default argument is within an
unevaluated context.

llvm-svn: 363113
2019-06-11 23:51:46 +00:00
Richard Smith 7bf8f6fa8a PR42104: Support instantiations of lambdas that implicitly capture
packs.

Two changes:
 * Track odr-use via FunctionParmPackExprs to properly handle dependent
   odr-uses of packs in generic lambdas.
 * Do not instantiate implicit captures; instead, regenerate them by
   instantiating the body of the lambda. This is necessary to
   distinguish between cases where only one element of a pack is
   captured and cases where the entire pack is captured.

This reinstates r362358 (reverted in r362375) with a fix for an
uninitialized variable use in UpdateMarkingForLValueToRValue.

llvm-svn: 362531
2019-06-04 17:17:20 +00:00
Simon Pilgrim c716e5d6de Revert rL362358 : PR42104: Support instantiations of lambdas that implicitly capture packs.
Two changes:
 * Track odr-use via FunctionParmPackExprs to properly handle dependent
   odr-uses of packs in generic lambdas.
 * Do not instantiate implicit captures; instead, regenerate them by
   instantiating the body of the lambda. This is necessary to
   distinguish between cases where only one element of a pack is
   captured and cases where the entire pack is captured.
........
Fixes http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win buildbot failures

llvm-svn: 362375
2019-06-03 09:56:09 +00:00
Richard Smith ea0c66be55 PR42104: Support instantiations of lambdas that implicitly capture
packs.

Two changes:
 * Track odr-use via FunctionParmPackExprs to properly handle dependent
   odr-uses of packs in generic lambdas.
 * Do not instantiate implicit captures; instead, regenerate them by
   instantiating the body of the lambda. This is necessary to
   distinguish between cases where only one element of a pack is
   captured and cases where the entire pack is captured.

llvm-svn: 362358
2019-06-03 06:02:10 +00:00
Richard Smith b2997f579a [c++20] P0780R2: Support pack-expansion of init-captures.
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
2019-05-21 20:10:50 +00:00
Richard Smith beda951d78 Make tentative parsing to detect template-argument-lists less aggressive
(and less wrong).

It's not correct to assume that X<something, Type> is always a
template-id; there are a few cases where the comma takes us into a
non-expression syntactic context in which 'Type' might be permissible.
Stop doing that.

This slightly regresses our error recovery on the cases where the
construct is intended to be a template-id. We typically do still manage
to diagnose a missing 'template' keyword, but we realize this too late
to properly recover from the error.

This fixes a regression introduced by r360308.

llvm-svn: 360827
2019-05-15 23:36:14 +00:00
Richard Smith c7214f6510 PR41845: Detect and reject mismatched inner/outer pack expansion sizes
in fold expressions rather than crashing.

llvm-svn: 360563
2019-05-13 08:31:14 +00:00
Paul Robinson d5d4df98bb Replace 'REQUIRES: not_?san' with 'UNSUPPORTED: ?san' as that better
expresses the intent of the exclusion.

llvm-svn: 360447
2019-05-10 17:57:22 +00:00
Richard Smith b23c5e8c3d [c++20] Implement P0846R0: allow (ADL-only) calls to template-ids whose
template name is not visible to unqualified lookup.

In order to support this without a severe degradation in our ability to
diagnose typos in template names, this change significantly restructures
the way we handle template-id-shaped syntax for which lookup of the
template name finds nothing.

Instead of eagerly diagnosing an undeclared template name, we now form a
placeholder template-name representing a name that is known to not find
any templates. When the parser sees such a name, it attempts to
disambiguate whether we have a less-than comparison or a template-id.
Any diagnostics or typo-correction for the name are delayed until its
point of use.

The upshot should be a small improvement of our diagostic quality
overall: we now take more syntactic context into account when trying to
resolve an undeclared identifier on the left hand side of a '<'. In
fact, this works well enough that the backwards-compatible portion (for
an undeclared identifier rather than a lookup that finds functions but
no function templates) is enabled in all language modes.

llvm-svn: 360308
2019-05-09 03:31:27 +00:00
Richard Smith 2b45b267da P1286R2: Remove restriction that the exception specification of a
defaulted special member matches the implicit exception specification.

llvm-svn: 360011
2019-05-06 05:04:56 +00:00
Richard Smith a6b41d7c52 CWG issue 727: Fix numerous bugs in support for class-scope explicit
specializations for variable templates.

llvm-svn: 359947
2019-05-03 23:51:38 +00:00
Richard Smith 59d0500bd0 PR41607: Don't forget to substitute outer template arguments into a
class-scope explicit specialization of a class template.

llvm-svn: 359266
2019-04-26 02:11:23 +00:00
Richard Smith 964f935e33 PR41427: This has apparently been fixed already, just add a regression
test.

llvm-svn: 359155
2019-04-24 23:45:56 +00:00
Erich Keane 505427cb2f Permit redeclarations of a builtin to specify calling convention.
After https://reviews.llvm.org/rL355317 we noticed that quite a decent
amount of code redeclares builtins (memcpy in particular, I believe
reduced from an MSVC header) with a calling convention specified.
This gets particularly troublesome when the user specifies a new
'default' calling convention on the command line.

When looking to add a diagnostic for this case, it was noticed that we
had 3 other diagnostics that differed only slightly.  This patch ALSO
unifies those under a 'select'.  Unfortunately, the order of words in
ONE of these diagnostics was reversed ("'thiscall' calling convention"
vs "calling convention 'thiscall'"), so this patch also standardizes on
the former.

Differential Revision: https://reviews.llvm.org/D59560

Change-Id: I79f99fe7c2301640755ffdd774b46eb44526bb22
llvm-svn: 356663
2019-03-21 13:30:56 +00:00
Erik Pilkington 13ee62f7d7 [Sema] Deduplicate some availability checking logic
Before this commit, we emit unavailable errors for calls to functions during
overload resolution, and for references to all other declarations in
DiagnoseUseOfDecl. The early checks during overload resolution aren't as good as
the DiagnoseAvailabilityOfDecl based checks, as they error on the code from
PR40991. This commit fixes this by removing the early checking.

llvm.org/PR40991
rdar://48564179

Differential revision: https://reviews.llvm.org/D59394

llvm-svn: 356599
2019-03-20 19:26:33 +00:00
Richard Trieu ef1e06df6f Remove an assert in template pack deduction during nested instantiation.
llvm-svn: 356231
2019-03-15 04:26:02 +00:00
Reid Kleckner 2bc58bd06d [MS] Fix for Bug 8446, template instantiation without a 'typename' keyword
Patch by Zahira Ammarguellat!

Differential Revision: https://reviews.llvm.org/D41950

llvm-svn: 354838
2019-02-26 02:22:17 +00:00
Richard Smith afcfb6bc3a Fix implementation of [temp.local]p4.
When a template-name is looked up, we need to give injected-class-name
declarations of class templates special treatment, as they denote a
template rather than a type.

Previously we achieved this by applying a filter to the lookup results
after completing name lookup, but that is incorrect in various ways, not
least of which is that it lost all information about access and how
members were named, and the filtering caused us to generally lose
all ambiguity errors between templates and non-templates.

We now preserve the lookup results exactly, and the few places that need
to map from a declaration found by name lookup into a declaration of a
template do so explicitly. Deduplication of repeated lookup results of
the same injected-class-name declaration is done by name lookup instead
of after the fact.

This reinstates r354091, which was previously reverted in r354097
because it exposed bugs in lldb and compiler-rt. Those bugs were fixed
in r354173 and r354174 respectively.

llvm-svn: 354176
2019-02-15 21:53:07 +00:00
Francis Visoiu Mistrih 0650f897a4 Revert "Fix implementation of [temp.local]p4."
This reverts commit 40bd10b770.

This seems to now emit an error when building the sanitizer tests:
http://green.lab.llvm.org/green/job/clang-stage1-configure-RA/53965/consoleFull.

llvm-svn: 354097
2019-02-15 03:06:15 +00:00
Richard Smith 40bd10b770 Fix implementation of [temp.local]p4.
When a template-name is looked up, we need to give injected-class-name
declarations of class templates special treatment, as they denote a
template rather than a type.

Previously we achieved this by applying a filter to the lookup results
after completing name lookup, but that is incorrect in various ways, not
least of which is that it lost all information about access and how
members were named, and the filtering caused us to generally lose
all ambiguity errors between templates and non-templates.

We now preserve the lookup results exactly, and the few places that need
to map from a declaration found by name lookup into a declaration of a
template do so explicitly. Deduplication of repeated lookup results of
the same injected-class-name declaration is done by name lookup instead
of after the fact.

llvm-svn: 354091
2019-02-15 00:29:04 +00:00
Nemanja Ivanovic db64e7e9fa [NFC] Explicitly add -std=c++14 option to tests that rely on the C++14 default
When Clang/LLVM is built with the CLANG_DEFAULT_STD_CXX CMake macro that sets
the default standard to something other than C++14, there are a number of lit
tests that fail as they rely on the C++14 default.
This patch just adds the language standard option explicitly to such test cases.

Differential revision: https://reviews.llvm.org/D57581

llvm-svn: 353163
2019-02-05 12:05:53 +00:00
Richard Smith 64095fc07c Remember to instantiate explicit template argument lists in a friend
function declaration.

We'd previously often just drop these on the floor, and friend
redeclaration matching would usually (but not always) figure out the
right redeclaration anyway.

Also, don't try to match a dependent friend function template
specialization to a template until instantiation, and don't forget to
reject qualified friend declarations in dependent contexts that don't
name an already-declared entity.

llvm-svn: 350915
2019-01-11 01:59:33 +00:00
Richard Smith 6e67142142 Fix crash if an in-class explicit function specialization has explicit
template arguments referring to template paramaeters.

llvm-svn: 348313
2018-12-04 22:26:32 +00:00
Richard Smith 02a84c8d0c PR12884: Add test (bug is already fixed).
llvm-svn: 347729
2018-11-28 05:15:46 +00:00
Richard Smith e54d9525ad PR39231: fix null dereference when diagnosing deduction failure due to
conflicting values for a non-type pack.

llvm-svn: 344070
2018-10-09 18:49:22 +00:00
Richard Smith 9b2c5e7c44 [cxx2a] P0641R2: (Some) type mismatches on defaulted functions only
render the function deleted instead of rendering the program ill-formed.

This change also adds an enabled-by-default warning for the case where
an explicitly-defaulted special member function of a non-template class
is implicitly deleted by the type checking rules. (This fires either due
to this language change or due to pre-C++20 reasons for the member being
implicitly deleted). I've tested this on a large codebase and found only
bugs (where the program means something that's clearly different from
what the programmer intended), so this is enabled by default, but we
should revisit this if there are problems with this being enabled by
default.

llvm-svn: 343285
2018-09-28 01:16:43 +00:00
Richard Smith 5159bbad8b PR38627: Fix handling of exception specification adjustment for
destructors.

We previously tried to patch up the exception specification after
completing the class, which went wrong when the exception specification
was needed within the class body (in particular, by a friend
redeclaration of the destructor in a nested class). We now mark the
destructor as having a not-yet-computed exception specification
immediately after creating it.

This requires delaying various checks against the exception
specification (where we'd previously have just got the wrong exception
specification, and now find we have an exception specification that we
can't compute yet) when those checks fire while the class is being
defined.

This also exposed an issue that we were missing a CodeSynthesisContext
for computation of exception specifications (otherwise we'd fail to make
the module containing the definition of the class visible when computing
its members' exception specs). Adding that incidentally also gives us a
diagnostic quality improvement.

This has also exposed an pre-existing problem: making the exception
specification evaluation context a non-SFINAE context (as it should be)
results in a bootstrap failure; PR38850 filed for this.

llvm-svn: 341499
2018-09-05 22:30:37 +00:00
Petr Hosek eb46c95c3e [CMake] Use normalized Windows target triples
Changes the default Windows target triple returned by
GetHostTriple.cmake from the old environment names (which we wanted to
move away from) to newer, normalized ones. This also requires updating
all tests to use the new systems names in constraints.

Differential Revision: https://reviews.llvm.org/D47381

llvm-svn: 339307
2018-08-09 02:16:18 +00:00
Erik Pilkington 9f9462acf6 [Sema] Ensure an auto non-type template parameter is dependent
The dependent auto was getting stripped away while rebuilding the template
parameter type, so substitute it in.

rdar://41852459

Differential revision: https://reviews.llvm.org/D50088

llvm-svn: 339198
2018-08-07 22:59:02 +00:00
Michael Kruse dc5ce72afa Append new attributes to the end of an AttributeList.
Recommit of r335084 after revert in r335516.

... instead of prepending it at the beginning (the original behavior
since implemented in r122535 2010-12-23). This builds up an
AttributeList in the the order in which the attributes appear in the
source.

The reverse order caused nodes for attributes in the AST (e.g. LoopHint)
to be in the reverse order, and therefore printed in the wrong order in
-ast-dump. Some TODO comments mention this. The order was explicitly
reversed for enable_if attribute overload resolution and name mangling,
which is not necessary anymore with this patch.

The change unfortunately has some secondary effect, especially on
diagnostic output. In the simplest cases, the CHECK lines or expected
diagnostic were changed to the the new output. If the kind of
error/warning changed, the attributes' order was changed instead.

This unfortunately causes some 'previous occurrence here' hints to be
textually after the main marker. This typically happens when attributes
are merged, but are incompatible to each other. Interchanging the role
of the the main and note SourceLocation will also cause the case where
two different declaration's attributes (in contrast to multiple
attributes of the same declaration) are merged to be reverse. There is
no easy fix because sometimes previous attributes are merged into a new
declaration's attribute list, sometimes new attributes are added to a
previous declaration's attribute list. Since 'previous occurrence here'
pointing to locations after the main marker is not rare, I left the
markers as-is; it is only relevant when the attributes are declared in
the same declaration anyway.

Differential Revision: https://reviews.llvm.org/D48100

llvm-svn: 338800
2018-08-03 01:21:16 +00:00
Richard Smith cc4ad95c30 PR38257: don't perform ADL when instantiating a unary & operator that turns out
to be forming a pointer-to-member.

llvm-svn: 337653
2018-07-22 05:21:47 +00:00
Richard Smith d4d6e21269 Fix failing testcase to actually be valid.
llvm-svn: 337483
2018-07-19 19:05:13 +00:00
Richard Smith 4a8f3518cb Fix template argument deduction when a parameter pack has a value
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
2018-07-19 19:00:37 +00:00
Richard Smith c2dead4d9a Diagnose missing 'template' keywords in contexts where a comma is not a
binary operator.

Factor out the checking for a comma within potential angle brackets and
also call it from contexts where we parse a comma-separated list of
arguments or initializers.

llvm-svn: 335699
2018-06-27 01:32:04 +00:00
Richard Smith bf5bcf2c15 Diagnose missing 'template' keywords in more cases.
We track when we see a name-shaped expression followed by a '<' token
and parse the '<' as a comparison. Then:

 * if we see a token sequence that cannot possibly be an expression but
   can be a template argument (in particular, a type-id) that follows
   either a ',' or the '<', diagnose that the '<' was supposed to start
   a template argument list, and
 * if we see '>()', diagnose that the '<' was supposed to start a
   template argument list.

This only changes the diagnostic for error cases, and in practice
appears to catch the most common cases where a missing 'template'
keyword leads to parse errors within a template.

Differential Revision: https://reviews.llvm.org/D48571

llvm-svn: 335687
2018-06-26 23:20:26 +00:00
Michael Kruse 41dd6ced2c Revert "Append new attributes to the end of an AttributeList."
This reverts commit r335084 as requested by David Jones and
Eric Christopher because of differences of emitted warnings.

llvm-svn: 335516
2018-06-25 20:06:13 +00:00
Michael Kruse ea31f0e4b8 Append new attributes to the end of an AttributeList.
... instead of prepending it at the beginning (the original behavior
since implemented in r122535 2010-12-23). This builds up an
AttributeList in the the order in which the attributes appear in the
source.

The reverse order caused nodes for attributes in the AST (e.g. LoopHint)
to be in the reverse, and therefore printed in the wrong order by
-ast-dump. Some TODO comments mention this. The order was explicitly
reversed for enable_if attribute overload resolution and name mangling,
which is not necessary anymore with this patch.

The change unfortunately has some secondary effects, especially for
diagnostic output. In the simplest cases, the CHECK lines or expected
diagnostic were changed to the the new output. If the kind of
error/warning changed, the attribute's order was changed instead.

It also causes some 'previous occurrence here' hints to be textually
after the main marker. This typically happens when attributes are
merged, but are incompatible. Interchanging the role of the the main
and note SourceLocation will also cause the case where two different
declaration's attributes (in contrast to multiple attributes of the
same declaration) are merged to be reversed. There is no easy fix
because sometimes previous attributes are merged into a new
declaration's attribute list, sometimes new attributes are added to a
previous declaration's attribute list. Since 'previous occurrence here'
pointing to locations after the main marker is not rare, I left the
markers as-is; it is only relevant when the attributes are declared in
the same declaration anyway, which often is on the same line.

Differential Revision: https://reviews.llvm.org/D48100

llvm-svn: 335084
2018-06-19 23:46:52 +00:00
Richard Smith ef53a3e2b6 PR37680: fix faulty assertion condition.
When looking up a template name, we can find an overload set containing a
function template and an unresolved non-type using declaration.

llvm-svn: 334106
2018-06-06 16:36:56 +00:00
Volodymyr Sapsai 9b973483ed [Sema] Fix assertion when constructor is disabled with partially specialized template.
The added test case was triggering assertion

> Assertion failed: (!SpecializedTemplate.is<SpecializedPartialSpecialization*>() && "Already set to a class template partial specialization!"), function setInstantiationOf, file clang/include/clang/AST/DeclTemplate.h, line 1825.

It was happening with ClassTemplateSpecializationDecl
`enable_if_not_same<int, int>`. Because this template is specialized for
equal types not to have a definition, it wasn't instantiated and its
specialization kind remained TSK_Undeclared. And because it was implicit
instantiation, we didn't mark the decl as invalid. So when we try to
find the best matching partial specialization the second time, we hit
the assertion as partial specialization is already set.

Fix by reusing stored partial specialization when available, instead of
looking for the best match every time.

rdar://problem/39524996

Reviewers: rsmith, arphaman

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D46909

llvm-svn: 332509
2018-05-16 18:28:58 +00:00
Volodymyr Sapsai 2f649f3d7f [c++17] Fix assertion on synthesizing deduction guides after a fatal error.
After a fatal error Sema::InstantiatingTemplate doesn't allow further
instantiation and doesn't push a CodeSynthesisContext. When we tried to
synthesize implicit deduction guides from constructors we hit the
assertion

> Assertion failed: (!CodeSynthesisContexts.empty() && "Cannot perform an instantiation without some context on the " "instantiation stack"), function SubstType, file clang/lib/Sema/SemaTemplateInstantiate.cpp, line 1580.

Fix by avoiding deduction guide synthesis if InstantiatingTemplate is invalid.

rdar://problem/39051732

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D46446

llvm-svn: 332307
2018-05-14 22:49:44 +00:00
Richard Smith cbebd6226d Fix regression in r332076.
If the name after 'template' is an unresolved using declaration (not containing
'typename'), then we don't yet know if it's a valid template-name, so don't
reject it prior to instantiation. Instead, treat it as naming a dependent
member of the current instantiation.

llvm-svn: 332291
2018-05-14 20:52:48 +00:00
Richard Smith 7981004eb7 Improve diagnostics and error recovery for template name lookup.
For 'x::template y', consistently give a "no member named 'y' in 'x'"
diagnostic if there is no such member, and give a 'template keyword not
followed by a template' name error if there is such a member but it's not a
template. In the latter case, add a note pointing at the non-template.

Don't suggest inserting a 'template' keyword in 'X::Y<' if X is dependent
if the lookup of X::Y was actually not a dependent lookup and found only
non-templates.

llvm-svn: 332076
2018-05-11 02:43:08 +00:00
Erich Keane c90bb6d762 Fix explicit template parameter reporting for narrowing conversions
I found that explicit template parameters that caused a
narrowing integer conversion resulted in the incorrect parameter
being mentioned in the note (see test attached). This is because
the argument checking code doesn't check to see if it caused
SFINAE errors when checking the arguments, so instead of giving
up on the first error, it continues through the list. This
makes the error reporting pick up the last template param every time.

This patch checks these parameters on each argument and gives up
if there is an error. The result is that only the required amount
of arguments are checked, and that the 'Converted' array contains
only the successful arguments before the first failure, as the
calls seem to all expect.

llvm-svn: 331651
2018-05-07 17:05:20 +00:00
Lei Liu 413f3c5595 [Sema] Do not match function type with const T in template argument deduction
From http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1584,
function type should not match cv-qualified type in template argument
deduction. This also matches what GCC and EDG do in template argument
deduction.

Differential Revision: https://reviews.llvm.org/D45755

llvm-svn: 331424
2018-05-03 01:43:23 +00:00
Richard Smith c08b693e30 Parse A::template B as an identifier rather than as a template-id with no
template arguments.

This fixes some cases where we'd incorrectly accept "A::template B" when B is a
kind of template that requires template arguments (in particular, a variable
template or a concept).

llvm-svn: 331013
2018-04-27 02:00:13 +00:00
Richard Smith ecad88d2bb Factor out common code for diagnosing missing template arguments.
In passing, add 'concept' to the list of template kinds in diagnostics.

llvm-svn: 330890
2018-04-26 01:08:00 +00:00
Richard Smith 0bf96f933a Fix crash on qualified template name instantiation if the template name has no
template argument list.

llvm-svn: 330881
2018-04-25 22:58:55 +00:00
Richard Trieu b402580616 Fix some handling of AST nodes with diagnostics.
The diagnostic system for Clang can already handle many AST nodes.  Instead
of converting them to strings first, just hand the AST node directly to
the diagnostic system and let it handle the output.  Minor changes in some
diagnostic output.

llvm-svn: 328688
2018-03-28 04:16:13 +00:00
Reid Kleckner 24bd88c0b0 [MS] Fix late-parsed template infinite loop in eager instantiation
Summary:
This fixes PR33561 and PR34185.

Don't store pending template instantiations for late-parsed templates in
the normal PendingInstantiations queue. Instead, use a separate list
that will only be parsed and instantiated at end of TU when late
template parsing actually works and doesn't infinite loop.

Reviewers: rsmith, thakis, hans

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D44846

llvm-svn: 328567
2018-03-26 18:22:47 +00:00
Richard Smith c660c8f5d2 Implement C++ DR727, which permits explicit specializations at class scope.
More generally, this permits a template to be specialized in any scope in which
it could be defined, so this also supersedes DR44 and DR374 (the latter of
which we previously only implemented in C++11 mode onwards due to unclarity as
to whether it was a DR).

llvm-svn: 327705
2018-03-16 13:36:56 +00:00
Richard Smith 5d3310208a When substituting previously-checked template arguments into a template
template parameter that is an expanded parameter pack, only substitute into the
current slice, not the entire pack.

This reduces the checking of N template template arguments for an expanded
parameter pack containing N parameters from quadratic time to linear time in
the length of the pack. This is important because one (and possibly the only?)
general technique for splitting a template parameter pack in linear time
depends on doing this.

llvm-svn: 326973
2018-03-08 01:07:33 +00:00