Add ThreadId for comparing threads
This adds the capability to store and compare threads with the current calling thread via a new struct, `std:🧵:ThreadId`. Addresses the need outlined in issue #21507.
This avoids the need to add any special checks to the existing thread structs and does not rely on the system to provide an identifier for a thread, since it seems that this approach is unreliable and undesirable. Instead, this simply uses a lazily-created, thread-local `usize` whose value is copied from a global atomic counter. The code should be simple enough that it should be as much reliable as the `#[thread_local]` attribute it uses (however much that is).
`ThreadId`s can be compared directly for equality and have copy semantics.
Also see these other attempts:
- rust-lang/rust#29457
- rust-lang/rust#29448
- rust-lang/rust#29447
And this in the RFC repo: rust-lang/rfcs#1435
Logically, it's a vector of pairs, so might as well represent it that
way.
The commit also changes `scan_stack` so that it is initialized with the
default size, instead of the excessive `55 * linewidth` size, which it
usually doesn't get even close to reaching.
`opaque::Decoder::read_str` is very hot within `rustc` due to its use in
the reading of crate metadata, and it currently returns a `String`. This
commit changes it to instead return a `Cow<str>`, which avoids a heap
allocation.
This change reduces the number of calls to `malloc` by almost 10% in
some benchmarks.
This is a [breaking-change] to libserialize.
These functions allow to read from and write to a file in one atomic
action from multiple threads, avoiding the race between the seek and the
read.
The functions are named `{read,write}_at` on non-Windows (which don't
change the file cursor), and `seek_{read,write}` on Windows (which
change the file cursor).
rustbuild: Optimize build times slightly
As the entry point for building the Rust compiler, a good user experience hinges
on this compiling quickly to get to the meat of the problem. To that end use
`#[cfg]`-specific dependencies to avoid building Windows crates on Unix and drop
the `regex` crate for now which was easily replacable with some string
searching.
As the entry point for building the Rust compiler, a good user experience hinges
on this compiling quickly to get to the meat of the problem. To that end use
`#[cfg]`-specific dependencies to avoid building Windows crates on Unix and drop
the `regex` crate for now which was easily replacable with some string
searching.
Leverage Cargo workspaces in rustbuild
This is a continuation of https://github.com/rust-lang/rust/pull/36032 which implements the change to use `cargo metadata` to learn about the crate graph.
Prevent accidentally running 'make install' as sudo.
r? @alexcrichton
I missed this in the previous PR, but this seems to work. It should probably go in a rollup, but I don't know how to do those. :/
Avoid some `pat_to_string` calls.
`ty_of_method_or_bare_fn` currently calls `pat_to_string` even when it
doesn't need to. Fixing this avoids hundreds of large allocations (e.g.
171,600 bytes, in `mk_printer`) in several of rustc-benchmarks.
