LinkedList: drop remaining items when drop panics
https://github.com/rust-lang/rust/pull/67235, but for `LinkedList`, which has the same issue.
I've also copied over the other drop-related tests from `VecDeque` since AFAICT `LinkedList` didn't have any.
Match `VecDeque::extend` to `Vec::extend_desugared`
Currently, `VecDeque::extend` [does not reserve at all](https://github.com/rust-lang/rust/pull/65069#discussion_r333166522). This implementation still runs a check every iteration of the loop, but should reallocate at most once for the common cases where the `size_hint` lower bound is exact. Further optimizations in the future could improve this for some common cases, but given the complexity of the `Vec::extend` implementation it's not immediately clear that this would be worthwhile.
This commit implements the `write_vectored` method of the `LineWriter`
type. First discovered in bytecodealliance/wasmtime#629 the
`write_vectored` method of `Stdout` bottoms out here but only ends up
writing the first buffer due to the default implementation of
`write_vectored`.
Like `BufWriter`, however, `LineWriter` can have a non-default
implementation of `write_vectored` which tries to preserve the
vectored-ness as much as possible. Namely we can have a vectored write
for everything before the newline and everything after the newline if
all the stars align well.
Also like `BufWriter`, though, special care is taken to ensure that
whenever bytes are written we're sure to signal success since that
represents a "commit" of writing bytes.
In particular, it has bugged me for some time that `process_cycles` is
currently located before `mark_still_waiting_nodes` despite being called
afterwards.
`NodeState` has two states, `Success` and `Done`, that are only used
within `ObligationForest` methods. This commit removes them, and renames
the existing `Waiting` state as `Success`.
We are left with three states: `Pending`, `Success`, and `Error`.
`Success` is augmented with a new `WaitingState`, which indicates when
(if ever) it was last waiting on one or more `Pending` nodes. This
notion of "when" requires adding a "process generation" to
`ObligationForest`; it is incremented on each call to
`process_obligtions`.
This commit is a performance win.
- Most of the benefit comes from `mark_as_waiting` (which the commit
renames as `mark_still_waiting_nodes`). This function used to do two
things: (a) change all `Waiting` nodes to `Success`, and (b) mark all
nodes that depend on a pending node as `Waiting`. In practice, many
nodes went from `Waiting` to `Success` and then immediately back to
`Waiting`. The use of generations lets us skip step (a).
- A smaller benefit comes from not having to change nodes to the `Done`
state in `process_cycles`.
Bootstrap: change logic for choosing linker and rpath
This is a follow-up from #66957 and #67023. Apparently there was one more location with a hard-coded list of targets to influence linking.
I've filed #67171 to track this madness.
r? @alexcrichton
rustllvm relies on the `LLVMRustStringWriteImpl` symbol existing, but
this symbol was previously defined in a *downstream* crate
(rustc_codegen_llvm, which depends on rustc_llvm.
While this somehow worked under the old 'separate bootstrap step for
codegen' scheme, it meant that rustc_llvm could not actually be built by
itself, since it relied linking to the downstream rustc_codegen_llvm
crate.
Now that librustc_codegen_llvm is just a normal crate, we actually try
to build a standalone rustc_llvm when we run tests. This commit moves
`LLVMRustStringWriteImpl` into rustc_llvm (technically the rustllvm
directory, which has its contents built by rustc_llvm). This ensures
that we can build each crate in the graph by itself, without requiring
that any downstream crates be linked in as well.
