Commit Graph

18 Commits

Author SHA1 Message Date
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 344df110e5 Implements CWG 1601 in [over.ics.rank/4.2]
Summary:
The overload resolution for enums with a fixed underlying type has changed in the C++14 standard. This patch implements the new rule.

Patch by Mark de Wever!

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65695

llvm-svn: 373866
2019-10-06 18:50:40 +00:00
Bruno Ricci af3e50ad40 [Sema] ADL: Associated namespaces for class types and enumeration types (CWG 1691)
CWG 1691 changed the definition of the namespaces associated with a class
type or enumeration type.

For a class type, the associated namespaces are the innermost enclosing
namespaces of the associated classes. For an enumeration type, the associated
namespace is the innermost enclosing namespace of its declaration.

This also fixes CWG 1690 and CWG 1692.

Differential Revision: https://reviews.llvm.org/D60573

Reviewed By: rjmccall, rsmith

llvm-svn: 358882
2019-04-22 12:19:00 +00:00
Richard Smith 0e3102d1dc Warn if a local variable's initializer retains a pointer/reference to a
non-lifetime-extended temporary object.

llvm-svn: 337790
2018-07-24 00:55:08 +00:00
Richard Smith afe48f9d68 Fold -Wreturn-stack-address into general initialization lifetime
checking.

llvm-svn: 337743
2018-07-23 21:21:22 +00:00
Richard Smith d87aab939a Restructure checking for, and warning on, lifetime extension.
This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
standard wording here is imprecise, but we interpret it as meaning that
any time a mem-initializer would result in lifetime extension, the
program is ill-formed.

This reinstates r337226, reverted in r337255, with a fix for the
InitializedEntity alignment problem that was breaking ARM buildbots.

llvm-svn: 337329
2018-07-17 22:24:09 +00:00
Florian Hahn 0aa117dd2c Temporarily revert r337226 "Restructure checking for, and warning on, lifetime extension."
This change breaks on ARM because pointers to clang::InitializedEntity are only
4 byte aligned and do not have 3 bits to store values. A possible solution
would be to change the fields in clang::InitializedEntity to enforce a bigger
alignment requirement.

The error message is

llvm/include/llvm/ADT/PointerIntPair.h:132:3: error: static_assert failed "PointerIntPair with integer size too large for pointer"
  static_assert(IntBits <= PtrTraits::NumLowBitsAvailable,
include/llvm/ADT/PointerIntPair.h:73:13: note: in instantiation of template class 'llvm::PointerIntPairInfo<const clang::InitializedEntity *, 3, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *> >' requested here
    Value = Info::updateInt(Info::updatePointer(0, PtrVal),
llvm/include/llvm/ADT/PointerIntPair.h:51:5: note: in instantiation of member function 'llvm::PointerIntPair<const clang::InitializedEntity *, 3, (anonymous namespace)::LifetimeKind, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *>, llvm::PointerIntPairInfo<const clang::InitializedEntity *, 3, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *> > >::setPointerAndInt' requested here
    setPointerAndInt(PtrVal, IntVal);
    ^
llvm/tools/clang/lib/Sema/SemaInit.cpp:6237:12: note: in instantiation of member function 'llvm::PointerIntPair<const clang::InitializedEntity *, 3, (anonymous namespace)::LifetimeKind, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *>, llvm::PointerIntPairInfo<const clang::InitializedEntity *, 3, llvm::PointerLikeTypeTraits<const clang::InitializedEntity *> > >::PointerIntPair' requested here
    return {Entity, LK_Extended};

Full log here:
http://lab.llvm.org:8011/builders/clang-cmake-armv7-global-isel/builds/1330
http://lab.llvm.org:8011/builders/clang-cmake-armv7-full/builds/1394

llvm-svn: 337255
2018-07-17 09:23:31 +00:00
Richard Smith 0a9969b36b Restructure checking for, and warning on, lifetime extension.
This change implements C++ DR1696, which makes initialization of a
reference member of a class from a temporary object ill-formed. The
standard wording here is imprecise, but we interpret it as meaning that
any time a mem-initializer would result in lifetime extension, the
program is ill-formed.

llvm-svn: 337226
2018-07-17 00:11:41 +00:00
Richard Smith 1ef7554efd DR1687: When overload resolution selects a built-in operator, implicit
conversions are only applied to operands of class type, and the second
standard conversion sequence is not applied.

When diagnosing an invalid builtin binary operator, talk about the
original types rather than the converted types. If these differ by a
user-defined conversion, tell the user what happened.

llvm-svn: 335781
2018-06-27 20:30:34 +00:00
Richard Smith b6070db0d0 DR1672, DR1813, DR1881, DR2120: Implement recent fixes to "standard
layout" rules.

The new rules say that a standard-layout struct has its first non-static
data member and all base classes at offset 0, and consider a class to
not be standard-layout if that would result in multiple subobjects of a
single type having the same address.

We track "is C++11 standard-layout class" separately from "is
standard-layout class" so that the ABIs that need this information can
still use it.

Differential Revision: https://reviews.llvm.org/D45176

llvm-svn: 329332
2018-04-05 18:55:37 +00:00
Richard Smith df054d3d22 C++ DR1611, 1658, 2180: implement "potentially constructed subobject" rules for special member functions.
Essentially, as a base class constructor does not construct virtual bases, such
a constructor for an abstract class does not need the corresponding base class
construction to be valid, and likewise for destructors.

This creates an awkward situation: clang will sometimes generate references to
the complete object and deleting destructors for an abstract class (it puts
them in the construction vtable for a derived class). But we can't generate a
"correct" version of these because we can't generate references to base class
constructors any more (if they're template specializations, say, we might not
have instantiated them and can't assume any other TU will emit a copy).
Fortunately, we don't need to, since no correct program can ever invoke them,
so instead emit symbols that just trap.

We should stop emitting references to these symbols, but still need to emit
definitions for compatibility.

llvm-svn: 296275
2017-02-25 23:53:05 +00:00
Richard Smith 836a3b416d PR31606: Generalize our tentative DR resolution for inheriting copy/move
constructors to better match the pre-P0136R1 behavior.

llvm-svn: 291955
2017-01-13 20:46:54 +00:00
Richard Smith d7279bba20 Update C++ status pages for Clang 4 branch:
* Update version number in DR tests from 4.0 to 4
 * Teach make_cxx_dr_status script about version numbers that don't contain a
   period.
 * Update cxx_status.html and cxx_dr_status.html to list Clang 4 features as
   "Clang 4" rather than "SVN"

Clang 4 features are still listed in yellow rather than green until release.

llvm-svn: 291871
2017-01-13 00:57:54 +00:00
Richard Smith b11b087a85 cxx_dr_status: update to latest issue list and add a couple more tests.
llvm-svn: 289255
2016-12-09 19:11:50 +00:00
Richard Smith 5179eb7821 P0136R1, DR1573, DR1645, DR1715, DR1736, DR1903, DR1941, DR1959, DR1991:
Replace inheriting constructors implementation with new approach, voted into
C++ last year as a DR against C++11.

Instead of synthesizing a set of derived class constructors for each inherited
base class constructor, we make the constructors of the base class visible to
constructor lookup in the derived class, using the normal rules for
using-declarations.

For constructors, UsingShadowDecl now has a ConstructorUsingShadowDecl derived
class that tracks the requisite additional information. We create shadow
constructors (not found by name lookup) in the derived class to model the
actual initialization, and have a new expression node,
CXXInheritedCtorInitExpr, to model the initialization of a base class from such
a constructor. (This initialization is special because it performs real perfect
forwarding of arguments.)

In cases where argument forwarding is not possible (for inalloca calls,
variadic calls, and calls with callee parameter cleanup), the shadow inheriting
constructor is not emitted and instead we directly emit the initialization code
into the caller of the inherited constructor.

Note that this new model is not perfectly compatible with the old model in some
corner cases. In particular:
 * if B inherits a private constructor from A, and C uses that constructor to
   construct a B, then we previously required that A befriends B and B
   befriends C, but the new rules require A to befriend C directly, and
 * if a derived class has its own constructors (and so its implicit default
   constructor is suppressed), it may still inherit a default constructor from
   a base class

llvm-svn: 274049
2016-06-28 19:03:57 +00:00
Richard Smith 420fa12dfd Improve the "braces around scalar init" warning to determine whether to warn
based on whether "redundant" braces are ever reasonable as part of the
initialization of the entity, rather than whether the initialization is
"top-level". In passing, add a warning flag for it.

llvm-svn: 228896
2015-02-12 01:50:05 +00:00
Larisse Voufo 4891e74c39 Re-arrange DR test cases, and update DR status page.
llvm-svn: 227279
2015-01-28 01:01:21 +00:00
Richard Smith b9be608f2d Add missing testcase from r224388.
llvm-svn: 224401
2014-12-17 01:08:39 +00:00