Warning for incorrect use of 'pure' attribute (#78200)

This adds a warning when applying the `pure` attribute along with the `const` attribute, or when applying the `pure` attribute to a function wi

Warning for incorrect use of 'pure' attribute (#78200)

This adds a warning when applying the `pure` attribute along with the `const` attribute, or when applying the `pure` attribute to a function with a `void` return type (including constructors and destructors).

Fixes https://github.com/llvm/llvm-project/issues/77482

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Defer checking for mismatches between the deletedness of and overriding
function and an overridden function until we know whether the overriding
function is deleted.

We previously did these checks w

Defer checking for mismatches between the deletedness of and overriding
function and an overridden function until we know whether the overriding
function is deleted.

We previously did these checks when we first built the declaration,
which was too soon in some cases. We now defer all these checks to the
end of the class.

Also add missing check that a consteval function cannot override a
non-consteval function and vice versa.

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Fix crash-on-invalid when trying to recover from a function template
being deleted on its second or subsequent declaration.

Implement isDefined by call to isThisDeclarationADefinition.

Modifies FunctionDecl::isThisDeclarationADefinition so that it covers
all the cases checked by FunctionDecl::isDefined. Implements the la

Implement isDefined by call to isThisDeclarationADefinition.

Modifies FunctionDecl::isThisDeclarationADefinition so that it covers
all the cases checked by FunctionDecl::isDefined. Implements the latter
method by call to isThisDeclarationADefinition.

This change is a part of the patch D30170.

llvm-svn: 304684

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Fix rejects-valid caused by r261297.

r261297 called hasUserProvidedDefaultConstructor() to check if defining a
const object is ok. This is incorrect for this example:

struct X { template<typenam

Fix rejects-valid caused by r261297.

r261297 called hasUserProvidedDefaultConstructor() to check if defining a
const object is ok. This is incorrect for this example:

struct X { template<typename ...T> X(T...); int n; };
const X x; // formerly OK, now bogus error

Instead, track if a class has a defaulted default constructor, and disallow
a const object for classes that either have defaulted default constructors or
if they need an implicit constructor.

Bug report and fix approach by Richard Smith, thanks!

llvm-svn: 261770

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Implement the likely resolution of core issue 253.

C++11 requires const objects to have a user-provided constructor, even for
classes without any fields. DR 253 relaxes this to say "If the implicit

Implement the likely resolution of core issue 253.

C++11 requires const objects to have a user-provided constructor, even for
classes without any fields. DR 253 relaxes this to say "If the implicit default
constructor initializes all subobjects, no initializer should be required."

clang is currently the only compiler that implements this C++11 rule, and e.g.
libstdc++ relies on something like DR 253 to compile in newer versions. This
change makes it possible to build code that says `const vector<int> v;' again
when using libstdc++5.2 and _GLIBCXX_DEBUG
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60284).

Fixes PR23381.

http://reviews.llvm.org/D16552

llvm-svn: 261297

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Move fixit for const init from note to diag, weaken to warning in MS mode.

r235046 turned "extern __declspec(selectany) int a;" from a declaration into
a definition to fix PR23242 (required for comp

Move fixit for const init from note to diag, weaken to warning in MS mode.

r235046 turned "extern __declspec(selectany) int a;" from a declaration into
a definition to fix PR23242 (required for compatibility with mc.exe output).
However, this broke parsing Windows headers: A d3d11 headers contain something
like

struct SomeStruct {};
extern const __declspec(selectany) SomeStruct some_struct;

This is now a definition, and const objects either need an explicit default
ctor or an initializer so this errors out with

d3d11.h(1065,48) :
error: default initialization of an object of const type
'const CD3D11_DEFAULT' without a user-provided default constructor

(cl.exe just doesn't implement this rule, independent of selectany.)

To work around this, weaken this error into a warning for selectany decls
in microsoft mode, and recover with zero-initialization.

Doing this is a bit hairy since it adds a fixit on an error emitted
by InitializationSequence – this means it needs to build a correct AST, which
in turn means InitializationSequence::Failed() cannot return true when this
fixit is applied. As a workaround, the patch adds a fixit member to
InitializationSequence, and InitializationSequence::Perform() prints the
diagnostic if the fixit member is set right after its call to Diagnose.
That function is usually called when InitializationSequences are used –
InitListChecker::PerformEmptyInit() doesn't call it, but the InitListChecker
case never performs default-initialization, so this is technically OK.

This is the alternative, original fix for PR20208 that got reviewed in the
thread "[patch] Improve diagnostic on default-initializing const variables
(PR20208)". This change basically reverts r213725, adds the original fix for
PR20208, and makes the error a warning in Microsoft mode.

llvm-svn: 235166

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Add tests for two more asserts that r226365 fixed according to SLi's bot.

llvm-svn: 226371

Add a test for something that used to crash before r226365.

llvm-svn: 226370

Improve diagnostic on default-initializing const variables (PR20208).

This tweaks the diagnostic wording slighly, and adds a fixit on a note.
An alternative would be to add the fixit directly on the

Improve diagnostic on default-initializing const variables (PR20208).

This tweaks the diagnostic wording slighly, and adds a fixit on a note.
An alternative would be to add the fixit directly on the diagnostic, see
the review thread linked to from the bug for a few notes on that approach.

llvm-svn: 213725

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PR16638, DR1552: the exception specification on an implicitly-declared
'operator delete' or 'operator delete[]' is an explicit exception
specification. Therefore we should diagnose 'void operator del

PR16638, DR1552: the exception specification on an implicitly-declared
'operator delete' or 'operator delete[]' is an explicit exception
specification. Therefore we should diagnose 'void operator delete(void*)'
instead of 'void operator delete(void*) noexcept'.

This diagnostic remains an ExtWarn, since in practice people don't always
include the exception specification in such a declaration.

llvm-svn: 201002

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Add implicit declarations of allocation functions when looking them up for
redeclaration, not just when looking them up for a use -- we need the implicit
declaration to appropriately check various pr

Add implicit declarations of allocation functions when looking them up for
redeclaration, not just when looking them up for a use -- we need the implicit
declaration to appropriately check various properties of them (notably, whether
they're deleted).

llvm-svn: 200729

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Properly compute triviality for explicitly-defaulted or deleted special members.
Remove pre-standard restriction on explicitly-defaulted copy constructors with
'incorrect' parameter types, and instea

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

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Explicitly defaulted constructors cannot be used for default initialization.

llvm-svn: 161088

Fold the six functions checking explicitly-defaulted special member functions
into one. These were all performing almost identical checks, with different bugs
in each of them.

This fixes PR12806 (we

Fold the six functions checking explicitly-defaulted special member functions
into one. These were all performing almost identical checks, with different bugs
in each of them.

This fixes PR12806 (we weren't setting the exception specification for an
explicitly-defaulted, non-user-provided default constructor) and enforces
8.4.2/2's rule that an in-class defaulted member must exactly match the implicit
parameter type.

llvm-svn: 156802

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Allow thread safety attributes on function definitions.
For compatibility with gcc, clang will now parse gcc attributes on
function definitions, but issue a warning if the attribute is not a
thread s

Allow thread safety attributes on function definitions.
For compatibility with gcc, clang will now parse gcc attributes on
function definitions, but issue a warning if the attribute is not a
thread safety attribute. Warning controlled by -Wgcc-compat.

llvm-svn: 150698

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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

constexpr functions are implicitly const. More tests to follow.

llvm-svn: 140831

Fix some minor bugs and add a lot more test cases for defaulted
constructors, including two more FIXMEs (one of which I don't actually
understand).

llvm-svn: 131487