The qualifier allows programmer to directly control how pointers are
signed when they are stored in a particular variable.

The qualifier takes three arguments: the signing key, a flag specifying
whether address discrimination should be used, and a non-negative
integer that is used for additional discrimination.

```
typedef void (*my_callback)(const void*);
my_callback __ptrauth(ptrauth_key_process_dependent_code, 1, 0xe27a) callback;
```

Co-Authored-By: John McCall rjmccall@apple.com

Static analysis detected that Demangler::demangleStringLiteral had a
potential overflow if not checking StringByteSize properly.

Added check to ensure that for wide string it is always even and that
there were the byte count did not mismatch the actual size of the
literal.

Fixes: https://github.com/llvm/llvm-project/issues/129970

This reverts commit 9d98acb196a40fee5229afeb08f95fd36d41c10a.

Line ending policies were changed in the parent, dccebddb3b80. To make
it easier to resolve downstream merge conflicts after line-ending
policies are adjusted this is a separate whitespace-only commit. If you
have merge conflicts as a result, you can simply `git add --renormalize
-u && git merge --continue` or `git add --renormalize -u && git rebase
--continue` - depending on your workflow.

Properly demangle `_T` and `_P` return type manglings for MSVC 1920+.
Also added a unit test for `@` return type that is used when mangling
non-template auto placeholder return type function.

Tested the output against the undname shipped with MSVC 19.40.

Fixes https://github.com/llvm/llvm-project/issues/70899.

This is a continuation of
https://github.com/llvm/llvm-project/pull/92477 for pointers to member
data and pointers to member functions.

The mangled name must be prefixed with `$M <mangled-type>` for the
deduced type of the nttp parameter.

As cited here, https://github.com/llvm/llvm-project/pull/92477, undname
needs updating to support the new auto NTTP name mangling.

In short the deduced type of the auto NTTP parameter is mangled as `$M
<type> <nttp-param>`. However the deduced type is not printed for the
undecorated name so the `$M <type>` is parsed but simply ignored when
stringifying the generated AST.

Skip *.pdb, *.rc, *crlf*, and FileCheck/dos-style-eol.txt

A follow up to commit 6bad76c7ae93 ("[Demangle] fix windows tests")
based on @thakis' report.

Fixes: #63740

Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D154875

This patch adds minimal support for D programming language demangling on LLVM
core based on the D name mangling spec. This will allow easier integration on a
future LLDB plugin for D either in the upstream tree or outside of it.

Minimal support includes recognizing D demangling encoding and at least one
mangling name, which in this case is `_Dmain` mangle.

Reviewed By: jhenderson, lattner

Differential Revision: https://reviews.llvm.org/D111414