resolves rust-lang#60580

This commit changes `created_files` so it uses strings directly as keys,
rather than symbols derived from the strings. This avoids the cost of
having to do the hash table lookups to produce the symbols from the
strings.

The commit also uses `entry` to avoid doing a repeated hash table lookup
(`get` + `insert`).

Note that PR rust-lang#60467 improved this code somewhat; this is a further
improvement.

…ndows.

convert custom try macro to `?`

resolves rust-lang#60580

r? @frewsxcv

Update boxed::Box docs on memory layout

The existing docs for the `Box` type state that "the way `Box` allocates and releases memory is unspecified", and that therefore the only valid pointer to pass to `Box::from_raw` is one obtained from `Box::into_raw`. This is inconsistent with the module-level docs which specify,

> It is valid to convert both ways between a Box and a raw pointer allocated with the Global allocator, given that the Layout used with the allocator is correct for the type. More precisely, a value: *mut T that has been allocated with the Global allocator with Layout::for_value(&*value) may be converted into a box using Box::<T>::from_raw(value). Conversely, the memory backing a value: *mut T obtained from Box::<T>::into_raw may be deallocated using the Global allocator with Layout::for_value(&*value).

This pull request updates the docs for `Box` to make them consistent with the module-level docs and adds some examples of how to use the global allocator in conjunction with `Box::from_raw` and `Box::into_raw`.

… r=michaelwoerister

Avoid symbol interning in `file_metadata`.

This commit changes `created_files` so it uses strings directly as keys,
rather than symbols derived from the strings. This avoids the cost of
having to do the hash table lookups to produce the symbols from the
strings.

The commit also uses `entry` to avoid doing a repeated hash table lookup
(`get` + `insert`).

Note that PR rust-lang#60467 improved this code somewhat; this is a further
improvement.

r? @davidtwco

Do not fail on child without DefId

Addresses rust-lang#60976, leaving open to come up with a repro case.

LocalDecl push returns Local len

r? @oli-obk

…base-dir, r=michaelwoerister

Add stream_to_parser_with_base_dir

This PR adds `stream_to_parser_with_base_dir`, which creates a parser from a token stream and a base directory.

Context: I would like to parse `cfg_if!` macro and get a list of modules defined inside it from rustfmt so that rustfmt can format those modules (cc rust-lang/rustfmt#3253). To do so, I need to create a parser from `TokenStream` and set the directory of `Parser` to the same directory as the parent directory of a file which contains `cfg_if!` invocation. AFAIK there is no way to achieve this, and hence this PR.

Alternatively, I could change the visibility of `Parser.directory` from `crate` to `pub` so that the value can be modified after initializing a parser. I don't have a preference over either approach (or others, as long as it works).

static_assert: make use of anonymous constants

…unwind, r=zackmdavis

Emit error when trying to use PGO in conjunction with unwinding on Windows.

This PR makes `rustc` emit an error when trying use PGO in conjunction with `-Cpanic=unwind` on Windows, isn't supported by LLVM yet. The error messages points to rust-lang#61002, which documents this known limitation.

adjust deprecation date of mem::uninitialized

In rust-lang#60445 we [decided](rust-lang#60445 (comment)) that we'd deprecate for 1.38 instead of 1.40, but I forgot to adjust for that.