[C++2a] P0634r3: Down with typename!

This patch implements P0634r3 that removes the need for 'typename' in certain contexts.

For example,

```
template <typename T>
using foo = T::type; // ok
```

[C++2a] P0634r3: Down with typename!

This patch implements P0634r3 that removes the need for 'typename' in certain contexts.

For example,

```
template <typename T>
using foo = T::type; // ok
```

This is also allowed in previous language versions as an extension, because I think it's pretty useful. :)

Reviewed By: #clang-language-wg, erichkeane

Differential Revision: https://reviews.llvm.org/D53847

show more ...

[Clang] Allow downgrading to a warning the diagnostic for setting a non fixed enum to a value outside the range of the enumeration values

In D130058 we diagnose the undefined behavior of setting the

[Clang] Allow downgrading to a warning the diagnostic for setting a non fixed enum to a value outside the range of the enumeration values

In D130058 we diagnose the undefined behavior of setting the value outside the
range of the enumerations values for an enum without a fixed underlying type.

Based on feedback we will provide users to the ability to downgrade this
diagnostic to a waring to allow for a transition period. We expect to turn this
diagnostic to an error in the next release.

Differential Revision: https://reviews.llvm.org/D131307

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could expose a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed wi

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit 7c51f02effdbd0d5e12bfd26f9c3b2ab5687c93f because it
stills breaks the LLDB tests. This was re-landed without addressing the
issue or even agreement on how to address the issue. More details and
discussion in https://reviews.llvm.org/D112374.

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

---

Troubleshooting list to deal with any breakage seen with this patch:

1) The most likely effect one would see by this patch is a change in how
a type is printed. The type printer will, by design and default,
print types as written. There are customization options there, but
not that many, and they mainly apply to how to print a type that we
somehow failed to track how it was written. This patch fixes a
problem where we failed to distinguish between a type
that was written without any elaborated-type qualifiers,
such as a 'struct'/'class' tags and name spacifiers such as 'std::',
and one that has been stripped of any 'metadata' that identifies such,
the so called canonical types.
Example:
```
namespace foo {
struct A {};
A a;
};
```
If one were to print the type of `foo::a`, prior to this patch, this
would result in `foo::A`. This is how the type printer would have,
by default, printed the canonical type of A as well.
As soon as you add any name qualifiers to A, the type printer would
suddenly start accurately printing the type as written. This patch
will make it print it accurately even when written without
qualifiers, so we will just print `A` for the initial example, as
the user did not really write that `foo::` namespace qualifier.

2) This patch could expose a bug in some AST matcher. Matching types
is harder to get right when there is sugar involved. For example,
if you want to match a type against being a pointer to some type A,
then you have to account for getting a type that is sugar for a
pointer to A, or being a pointer to sugar to A, or both! Usually
you would get the second part wrong, and this would work for a
very simple test where you don't use any name qualifiers, but
you would discover is broken when you do. The usual fix is to
either use the matcher which strips sugar, which is annoying
to use as for example if you match an N level pointer, you have
to put N+1 such matchers in there, beginning to end and between
all those levels. But in a lot of cases, if the property you want
to match is present in the canonical type, it's easier and faster
to just match on that... This goes with what is said in 1), if
you want to match against the name of a type, and you want
the name string to be something stable, perhaps matching on
the name of the canonical type is the better choice.

3) This patch could exposed a bug in how you get the source range of some
TypeLoc. For some reason, a lot of code is using getLocalSourceRange(),
which only looks at the given TypeLoc node. This patch introduces a new,
and more common TypeLoc node which contains no source locations on itself.
This is not an inovation here, and some other, more rare TypeLoc nodes could
also have this property, but if you use getLocalSourceRange on them, it's not
going to return any valid locations, because it doesn't have any. The right fix
here is to always use getSourceRange() or getBeginLoc/getEndLoc which will dive
into the inner TypeLoc to get the source range if it doesn't find it on the
top level one. You can use getLocalSourceRange if you are really into
micro-optimizations and you have some outside knowledge that the TypeLocs you are
dealing with will always include some source location.

4) Exposed a bug somewhere in the use of the normal clang type class API, where you
have some type, you want to see if that type is some particular kind, you try a
`dyn_cast` such as `dyn_cast<TypedefType>` and that fails because now you have an
ElaboratedType which has a TypeDefType inside of it, which is what you wanted to match.
Again, like 2), this would usually have been tested poorly with some simple tests with
no qualifications, and would have been broken had there been any other kind of type sugar,
be it an ElaboratedType or a TemplateSpecializationType or a SubstTemplateParmType.
The usual fix here is to use `getAs` instead of `dyn_cast`, which will look deeper
into the type. Or use `getAsAdjusted` when dealing with TypeLocs.
For some reason the API is inconsistent there and on TypeLocs getAs behaves like a dyn_cast.

5) It could be a bug in this patch perhaps.

Let me know if you need any help!

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module

Revert "[clang] Implement ElaboratedType sugaring for types written bare"

This reverts commit bdc6974f92304f4ed542241b9b89ba58ba6b20aa because it
breaks all the LLDB tests that import the std module.

import-std-module/array.TestArrayFromStdModule.py
import-std-module/deque-basic.TestDequeFromStdModule.py
import-std-module/deque-dbg-info-content.TestDbgInfoContentDequeFromStdModule.py
import-std-module/forward_list.TestForwardListFromStdModule.py
import-std-module/forward_list-dbg-info-content.TestDbgInfoContentForwardListFromStdModule.py
import-std-module/list.TestListFromStdModule.py
import-std-module/list-dbg-info-content.TestDbgInfoContentListFromStdModule.py
import-std-module/queue.TestQueueFromStdModule.py
import-std-module/stack.TestStackFromStdModule.py
import-std-module/vector.TestVectorFromStdModule.py
import-std-module/vector-bool.TestVectorBoolFromStdModule.py
import-std-module/vector-dbg-info-content.TestDbgInfoContentVectorFromStdModule.py
import-std-module/vector-of-vectors.TestVectorOfVectorsFromStdModule.py

https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/45301/

show more ...

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which go

[clang] Implement ElaboratedType sugaring for types written bare

Without this patch, clang will not wrap in an ElaboratedType node types written
without a keyword and nested name qualifier, which goes against the intent that
we should produce an AST which retains enough details to recover how things are
written.

The lack of this sugar is incompatible with the intent of the type printer
default policy, which is to print types as written, but to fall back and print
them fully qualified when they are desugared.

An ElaboratedTypeLoc without keyword / NNS uses no storage by itself, but still
requires pointer alignment due to pre-existing bug in the TypeLoc buffer
handling.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Differential Revision: https://reviews.llvm.org/D112374

show more ...

[-fms-extensions] Make some exception specification warnings/errors compatible with what cl.exe does

Make clang-cl error when a function definition is missing 'noexcept',
and succeed without warning

[-fms-extensions] Make some exception specification warnings/errors compatible with what cl.exe does

Make clang-cl error when a function definition is missing 'noexcept',
and succeed without warnings when missing '__declspec(nothrow)' or 'throw'.

Fixes pr52860

Differential Revision: https://reviews.llvm.org/D116256

show more ...

[clang-cl] [Sema] Do not prefer integral conversion over floating-to-integral for MS compatibility 19.28 and higher.

As of MSVC 19.28 (2019 Update 8), integral conversion is no longer preferred over

[clang-cl] [Sema] Do not prefer integral conversion over floating-to-integral for MS compatibility 19.28 and higher.

As of MSVC 19.28 (2019 Update 8), integral conversion is no longer preferred over floating-to-integral, and so MSVC is more standard conformant and will generate a compiler error on ambiguous call.
Cf. https://godbolt.org/z/E8xsdqKsb.
Initially found during the review of D99641.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D99663

show more ...

Fix checking for C++98 ICEs in C++11-and-later mode to not consider use
of a reference to be acceptable.

[MS] Warn when shadowing template parameters under -fms-compatibility

Summary:
C++ does not allow shadowing template parameters, but previously we
allowed it under -fms-extensions. Now this behavior

[MS] Warn when shadowing template parameters under -fms-compatibility

Summary:
C++ does not allow shadowing template parameters, but previously we
allowed it under -fms-extensions. Now this behavior is controlled by
-fms-compatibility, and we emit a -Wmicrosoft-template warning when it
happens.

Fixes PR43265

Reviewers: thakis, hans

Subscribers: amccarth, rsmith, STL_MSFT, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67463

llvm-svn: 371753

show more ...

Move EH spec mismatches under -fms-compatibility

-fms-extensions is intended to enable conforming language extensions and
-fms-compatibility is intended to language rule relaxations, so a user
could

Move EH spec mismatches under -fms-compatibility

-fms-extensions is intended to enable conforming language extensions and
-fms-compatibility is intended to language rule relaxations, so a user
could plausibly compile with -fno-ms-compatibility on Windows while
still using dllexport, for example. This exception specification
validation behavior has been handled as a warning since before
-fms-compatibility was added in 2011. I think it's just an oversight
that it hasn't been moved yet.

This will help users find conformance issues in their code such as those
found in _com_ptr_t as described in https://llvm.org/PR42842.

Reviewers: hans

Subscribers: STL_MSFT, cfe-commits

Differential Revision: https://reviews.llvm.org/D66770

llvm-svn: 370087

show more ...

[ms] Prevent explicit constructor name lookup if scope is missing

MicrosoftExt allows explicit constructor calls. Prevent lookup of constructor name unless the name has explicit scope.
This avoids a

[ms] Prevent explicit constructor name lookup if scope is missing

MicrosoftExt allows explicit constructor calls. Prevent lookup of constructor name unless the name has explicit scope.
This avoids a compile-time crash due to confusing a member access for a constructor name.

Test case included. All tests pass.

Differential Revision: https://reviews.llvm.org/D53441

llvm-svn: 345258

show more ...

[AST] Fix loss of enum forward decl from decl context

For example, given:

enum __attribute__((deprecated)) T *p;

-ast-print produced:

enum T *p;

The attribute was lost because the enum forwa

[AST] Fix loss of enum forward decl from decl context

For example, given:

enum __attribute__((deprecated)) T *p;

-ast-print produced:

enum T *p;

The attribute was lost because the enum forward decl was lost.

Another example is the loss of enum forward decls from C++ namespaces
(in MS compatibility mode).

The trouble was that the EnumDecl node was suppressed, as revealed by
-ast-dump. The suppression of the EnumDecl was intentional in
r116122, but I don't understand why. The suppression isn't needed for
the test suite to behave.

Reviewed by: rsmith

Differential Revision: https://reviews.llvm.org/D46846

llvm-svn: 333574

show more ...

[ms] Give -Wmicrosoft-enum-forward-reference a chance to fire in clang-cl, PR32736

clang-cl sets MicrosoftCompat. In that mode, we always give enums a fixed
underlying type, and for enums with fixed

[ms] Give -Wmicrosoft-enum-forward-reference a chance to fire in clang-cl, PR32736

clang-cl sets MicrosoftCompat. In that mode, we always give enums a fixed
underlying type, and for enums with fixed underlying type we never enter the
block that tries to emit ext_ms_forward_ref_enum. Fix this by requiring an
explicit underlying type when we're skipping this diagnostic.

We had a test for this warning, but it only ran in C++98 mode. clang-cl always
enables -std=c++14, so MicrosoftCompatibiliy-cxx98.cpp is a fairly useless
test. Fold it into MicrosoftCompatibility.cpp -- that way, the test checks if
-Wmicrosoft-enum-forward-reference can fire in clang-cl builds.

https://reviews.llvm.org/D32369

llvm-svn: 301032

show more ...

Sema: As of MSVC 2015, a user-declared move operation causes the deletion of both copy operations.

Differential Revision: https://reviews.llvm.org/D26868

llvm-svn: 287411

[MS] Move hex long long sign compat hack to -fms-compatibility

Treating large 0x*LL literals as signed instead of unsigned is not a
conforming language extension, so move it out of -fms-extensions.

[MS] Move hex long long sign compat hack to -fms-compatibility

Treating large 0x*LL literals as signed instead of unsigned is not a
conforming language extension, so move it out of -fms-extensions.

Came up in PR30605

llvm-svn: 283227

show more ...

[MS Compat] Allow _Atomic(Type) and 'struct _Atomic' to coexist

MSVC 2013 ships, as part of its STL implementation, a class named
'_Atomic'. This is unfortunate because this keyword is in conflict

[MS Compat] Allow _Atomic(Type) and 'struct _Atomic' to coexist

MSVC 2013 ships, as part of its STL implementation, a class named
'_Atomic'. This is unfortunate because this keyword is in conflict with
the C11 keyword with the same name. Our solution was to disable this
keyword when targeting MSVC 2013 and reenable it for 2015.

However, this makes it impossible for clang's headers to make use of
_Atomic. This is problematic in the case of libc++ as it makes heavy
use of this keyword.

Let the keywordness of _Atomic float under certain circumstances:
the body of a class named _Atomic, or a class with a base specifier
named _Atomic, will not have the keyword variant of _Atomic for the
duration of the class body. This is sufficient to allow us to correctly
handle _Atomic in the STL while permitting us to use _Atomic as a
keyword everywhere else.

Differential Revision: http://reviews.llvm.org/D11233

llvm-svn: 242970

show more ...

MS ABI: Define _HAS_CHAR16_T_LANGUAGE_SUPPORT when appropriate

If we are in MSVC 2015 compatibility mode and C++11 language conformance
is enabled, define _HAS_CHAR16_T_LANGUAGE_SUPPORT to 1.

llvm-

MS ABI: Define _HAS_CHAR16_T_LANGUAGE_SUPPORT when appropriate

If we are in MSVC 2015 compatibility mode and C++11 language conformance
is enabled, define _HAS_CHAR16_T_LANGUAGE_SUPPORT to 1.

llvm-svn: 232615

show more ...

MSVC Compat: Permit char16_t, char32_t and _Atomic when targeting > 2013

We disabled support for _Atomic because the STL had name conflicts,
they've been resolved in 2015. Similarly, reenable char1

MSVC Compat: Permit char16_t, char32_t and _Atomic when targeting > 2013

We disabled support for _Atomic because the STL had name conflicts,
they've been resolved in 2015. Similarly, reenable char16_t and
char32_t.

llvm-svn: 232611

show more ...

Reword switch/goto diagnostics "protected scope" diagnostics. Making up a term
"protected scope" is very unhelpful here and actively confuses users. Instead,
simply state the nature of the problem in

Reword switch/goto diagnostics "protected scope" diagnostics. Making up a term
"protected scope" is very unhelpful here and actively confuses users. Instead,
simply state the nature of the problem in the diagnostic: we cannot jump from
here to there. The notes explain nicely why not.

llvm-svn: 217293

show more ...

TokenKinds: _Atomic isn't a keyword in MS mode

Summary:
This is needed to allow MSVC's <atomic> header to properly parse.
It uses _Atomic as a class-id.

Reviewers: rnk

Reviewed By: rnk

CC: cfe-co

TokenKinds: _Atomic isn't a keyword in MS mode

Summary:
This is needed to allow MSVC's <atomic> header to properly parse.
It uses _Atomic as a class-id.

Reviewers: rnk

Reviewed By: rnk

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2948

llvm-svn: 202901

show more ...

Move the -fms-compatibility using decl check after real access checking

Summary:
This avoids false positives from -Wmicrosoft when name lookup would
normally succeed in standard C++. This triggered

Move the -fms-compatibility using decl check after real access checking

Summary:
This avoids false positives from -Wmicrosoft when name lookup would
normally succeed in standard C++. This triggered on a common CRTP
pattern in clang, where a derived class would have a private using decl
to pull in members of a dependent base:

class Verifier : InstVisitor<Verifier> {
private:
using InstVisitor<Verifier>::visit;
...
void anything() {
visit(); // warned here
}
};

Real access checks pass here because we're in the context of the
Verifier, but the -Wmicrosoft extension was just looking for the private
access specifier.

Reviewers: rsmith

CC: cfe-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2679

llvm-svn: 201019

show more ...

Restrict redeclaration of tags introduced by using decls to MSVCCompat

This limits the facility added in r199490 while we seek clarification on the
standard.

llvm-svn: 199531

Sema: Predefine size_t in MSVC Compatibility mode

MSVC defines size_t without any explicit declarations. This change
allows us to be compatible with TUs that depend on this declaration
appearing fr

Sema: Predefine size_t in MSVC Compatibility mode

MSVC defines size_t without any explicit declarations. This change
allows us to be compatible with TUs that depend on this declaration
appearing from nowhere.

llvm-svn: 199190

show more ...