Commit Graph

19 Commits

Author SHA1 Message Date
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 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 e3b28bc363 Move detection of reference members binding to temporaries from building of
CXXCtorInitializers to the point where we perform the questionable lifetime
extension. This exposed a selection of false negatives in the warning.

llvm-svn: 183869
2013-06-12 21:51:50 +00:00
Richard Smith bd3051272c PR14558: Compute triviality of special members (etc) at the end of the class
definition, rather than at the end of the definition of the set of nested
classes. We still defer checking of the user-specified exception specification
to the end of the nesting -- we can't check that until we've parsed the
in-class initializers for non-static data members.

llvm-svn: 169805
2012-12-11 01:14:52 +00:00
Richard Smith 92f241f188 Properly compute triviality for explicitly-defaulted or deleted special members.
Remove pre-standard restriction on explicitly-defaulted copy constructors with
'incorrect' parameter types, and instead just make those special members
non-trivial as the standard requires.

This required making CXXRecordDecl correctly handle classes which have both a
trivial and a non-trivial special member of the same kind.

This also fixes PR13217 by reimplementing DiagnoseNontrivial in terms of the
new triviality computation technology.

llvm-svn: 169667
2012-12-08 02:53:02 +00:00
Richard Smith c5f98f343b [class.copy]p23: Fix an assertion caused by incorrect argument numbering in a
diagnostic, add a test for this paragraph, and tighten up the diagnostic wording
a little.

llvm-svn: 155784
2012-04-29 06:32:34 +00:00
Richard Smith 6f1e2c6d19 Finish PR10217: Ensure we say that a special member was implicitly, not
explicitly, deleted in all relevant cases, and explain why.

llvm-svn: 153894
2012-04-02 20:59:25 +00:00
Richard Smith 852265ff1c PR10217: Provide diagnostics explaining why an implicitly-deleted special
member function is deleted.

llvm-svn: 153773
2012-03-30 20:53:28 +00:00
Richard Smith 619ecdc80f Ensure that we delete default constructors in the right cases. Don't delete the
default constructor of a union if it has a const member with no user-provided
default constructor.

llvm-svn: 151516
2012-02-27 06:07:25 +00:00
Richard Smith 0d1f3cb1b5 Special members which are defaulted or deleted on their first declaration are
trivial if the implicit declaration would be. Don't forget to set the Trivial
flag on the special member as well as on the class. It doesn't seem ideal that
we have two separate mechanisms for storing this information, but this patch
does not attempt to address that.

This leaves us in an interesting position where the has_trivial_X trait for a
class says 'yes' for a deleted but trivial X, but is_trivially_Xable says 'no'.
This seems to be what the standard requires.

llvm-svn: 151465
2012-02-26 00:31:33 +00:00
Douglas Gregor 74f7d50f6a When overload resolution picks an implicitly-deleted special member
function, provide a specialized diagnostic that indicates the kind of
special member function (default constructor, copy assignment
operator, etc.) and that it was implicitly deleted. Add a hook where
we can provide more detailed information later.

llvm-svn: 150611
2012-02-15 19:33:52 +00:00
Eli Friedman 4134073c4b Compute whether a class is trivial correctly for template classes with an explicitly deleted or defaulted special member. PR11387.
llvm-svn: 144715
2011-11-15 22:39:08 +00:00
Douglas Gregor 5d1b4e3d1f When we notice that a member function is defined with "= delete" or "=
default", make a note of which is used when creating the
initial declaration. Previously, we would wait until later to handle
default/delete as a definition, but this is too late: when adding the
declaration, we already treated the declaration as "user-provided"
when in fact it was merely "user-declared".

Fixes PR10861 and PR10442, along with a bunch of FIXMEs.

llvm-svn: 144011
2011-11-07 20:56:01 +00:00
Richard Smith 9ca5c42582 Update all tests other than Driver/std.cpp to use -std=c++11 rather than
-std=c++0x. Patch by Ahmed Charles!

llvm-svn: 141900
2011-10-13 22:29:44 +00:00
Alexis Hunt d6da876bac Begin work consolidating ShouldDelete* functions.
Begin with just default constructors. One note is that as a side effect
of this, a conformance test was removed on the basis that this is almost
certainly a defect as with most of union initialization. As it is, clang
does not implement union initialization close to the standard as it's
quite broken as written. I hope to write a paper addressing the issues
eventually.

llvm-svn: 141528
2011-10-10 06:18:57 +00:00
Richard Smith 938f40b5aa Implement support for C++11 in-class initialization of non-static data members.
llvm-svn: 132878
2011-06-11 17:19:42 +00:00