Changes

Fix flang tests after MLIR changes on the handling of declarative assembly

[clangd] Add desugared type to hover

Add desugared type to hover when the desugared type and the pretty-printed type are different.

```c++
template<typename T>
struct TestHover {
  using Type = T;
};

int main() {
  TestHover<int>::Type a;
}
```

```
variable a

Type: TestHover<int>::Type (aka int)
```

Reviewed By: sammccall

Differential Revision: https://reviews.llvm.org/D114522

[C++20] [Module] Support extern C/C++ semantics

According to [module.unit]p7.2.3, a declaration within a linkage-specification
should be attached to the global module.
This let user to forward declare types across modules.

Reviewed by: rsmith, aaron.ballman

Differential Revision: https://reviews.llvm.org/D110215

[NFC][lsan] Clang-format lsan_common.cpp

[NFC][lsan] Move method implementation up

[C++20] [Modules] Namespace Declaration shouldn't have module linkage

According to [basic.namespace.general]/p2, a namespace declaration
shouldn't have a module linkage.
> A namespace is never attached to a named module and never has a name
> with module linkage.

Without this patch, the compiler would crash for the test in assertion
enabled build due to inconsistent linkage for redeclaration for
namespaces.

Reviewed by: rsmith

Differential Revision: https://reviews.llvm.org/D115132

Build MLIR with -Werror=mismatched-tags (NFC)

This is a defensive action to catch at build time on Linux failures that
may happen only on Windows otherwise.

Differential Revision: https://reviews.llvm.org/D115316

Adjust "end namespace" comment in MLIR to match new agree'd coding style

See D115115 and this mailing list discussion:
https://lists.llvm.org/pipermail/llvm-dev/2021-December/154199.html

Differential Revision: https://reviews.llvm.org/D115309

[clangd] Make a.k.a printing configurable.

Currently, a.k.a printing is closed by default.

Reviewed By: sammccall, kadircet

Differential Revision: https://reviews.llvm.org/D114665

[NFC] Fix C++20 module test in PPC and warning

[NFC][asan] Remove -std=c++20 from test

Fails after D110215
with errors like
/usr/include/x86_64-linux-gnu/sys/types.h:33:9: error: unknown type name '__u_char'
typedef __u_char u_char;

[lsan] Replace atomic_store/atomic_load with atomic_fetch_add

[C++20] [Modules] [Concepts] Recognize same concepts more precisely in Serialization

The compiler would judge two concepts is same by their addresses.
However, when we use modules, the addresses wouldn't be the same all the
time since one is parsed in their TU and another is imported in another
TU.
This patch fixes this by using isSameEntity to judge the two concepts.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D114769

[CMake] Specify byproducts for custom libcxx builds

These were removed in bda3f2dd763b06427dd2713aa062e356c9d7bdc6 but
are needed as it turned out for the MSan tests.

Allow DataLayout to support arbitrary pointer sizes

Currently, it is impossible to specify a DataLayout with pointer
size and index size that is not a whole number of bytes.
This patch modifies
the DataLayout class to accept arbitrary pointer sizes and to
store the size as a number of bits, rather than as a number of bytes.
Generally speaking, the external interface of the class as used
by in-tree architectures remains the same and shouldn't affect the
behavior of architecures with pointer sizes equal to a whole number
of bytes.

Note the interface of setPointerAlignment has changed and takes
a pointer and index size that is a number of bits, rather than a number
of bytes.

Patch originally by Ajit Kumar Agarwal

Differential Revision: https://reviews.llvm.org/D114141