Moved -z ignore to add_as_needed

Trying to cross-compile for sparcv9-sun-solaris
getting an error message for -zignore

Introduced when -z -ignore was separated here
22d0ab0

No formatting done

Reproduce

``` bash
rustup target add sparcv9-sun-solaris
cargo new --bin hello && cd hello && cargo run --target=sparcv9-sun-solaris
```

config.toml

[target.sparcv9-sun-solaris]
linker = "gcc"

Fixes: rust-lang#84018

With `-Z instrument-coverage`, coverage reporting of dead blocks
(for example, blocks dropped because a conditional branch is dropped,
based on const evaluation) is now supported.

If `instrument-coverage` is enabled, `simplify::remove_dead_blocks()`
finds all dropped coverage `Statement`s and adds their `code_region`s as
`Unreachable` coverage `Statement`s to the `START_BLOCK`, so they are
still included in the coverage map.

Check out the resulting changes in the test coverage reports in this PR.

Fixes: rust-lang#83830

Fix rust-lang#84769, follow up to rust-lang#84499, rust-lang#83667.

Clippy: Decreases indentation and improves readability

Signed-off-by: wcampbell <wcampbell1995@gmail.com>

This extracts a new `parse_cfg` function that's used between both.

- Treat `#[doc(cfg(x), cfg(y))]` the same as `#[doc(cfg(x)]
  #[doc(cfg(y))]`. Previously it would be completely ignored.
- Treat `#[doc(inline, cfg(x))]` the same as `#[doc(inline)]
  #[doc(cfg(x))]`. Previously, the cfg would be ignored.
- Pass the cfg predicate through to rustc_expand to be validated

Co-authored-by: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>

This updates the documentation since `ptr::addr_of!` and
`ptr::addr_of_mut!` are now stable. One might remove the distinction
between the sections `# On packed structs` and `# Examples`, as the old
section on packed structs was primarily to prevent users of doing unde-
fined behavior, which is not necessary anymore.
There is also a new section in "how to obtain a pointer", which referen-
ces the `ptr::addr_of!` macros.

This commit contains squashed commits from code review.

Co-authored-by: Joshua Nelson <joshua@yottadb.com>
Co-authored-by: Mara Bos <m-ou.se@m-ou.se>
Co-authored-by: Soveu <marx.tomasz@gmail.com>
Co-authored-by: Ralf Jung <post@ralfj.de>

…items

Currently hex/octal/binary literals with computed values are displayed
like `0_xff_fff_fffu32`, which is invalid since underscores can't be in
the middle of integer prefixes. This properly formats prefixed integers.

…, r=pnkfelix

Improve diagnostic for when field is never read

Related to (but does not close) rust-lang#81658

This completes the first step of `@pnkfelix's` [mentoring instructions](rust-lang#81658 (comment)) but does not actually improve the diagnostics (yet!). The two tests are heavily reduced versions of code from the original bug report.

I've confirmed that the reduced `field-used-in-ffi` test [fails on nightly](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=f0862c89ddca028c55c20a5ed05e679a) but [passes on stable](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=f0862c89ddca028c55c20a5ed05e679a). This confirms that the regression is reproduced correctly. The `drop-only-field` test is a case that `@pnkfelix` mentioned in his mentoring instructions. It is not a regression, but will come in handy when we make the diagnostic smarter by looking at whether the field type implements `Drop`.

Per the [rustc-dev-guide](https://rustc-dev-guide.rust-lang.org/tests/adding.html), each test includes a comment summarizing what it is about.

Update `ptr` docs with regards to `ptr::addr_of!`

This updates the documentation since `ptr::addr_of!` and `ptr::addr_of_mut!` are now stable. One might remove the distinction between the sections `# On packed structs` and `# Examples`, as the old section on packed structs was primarily to prevent users of doing undefined behavior, which is not necessary anymore.

Technically there is now wrong/outdated documentation on stable, but I don't think this is worth a point release 😉

Fixes rust-lang#83509.

`@rustbot` modify labels: T-doc

…=jyn514

Valid underscores in hex/octal/binary literal docs

Currently hex/octal/binary literals with computed values are displayed like `0_xff_fff_fffu32`, which is invalid since underscores can't be in the middle of integer prefixes. This properly formats prefixed integers.

This causes  [`std::u32::MAX`](https://doc.rust-lang.org/std/u32/constant.MAX.html) to be displayed as
```rust
pub const MAX: u32 = u32::MAX; // 0_xff_fff_fffu32
```

This PR changes it to be displayed as:
```rust
pub const MAX: u32 = u32::MAX; // 0xffff_ffffu32
```

Unify rustc and rustdoc parsing of `cfg()`

This extracts a new `parse_cfg` function that's used between both.

- Treat `#[doc(cfg(x), cfg(y))]` the same as `#[doc(cfg(x)]
  #[doc(cfg(y))]`. Previously it would be completely ignored.
- Treat `#[doc(inline, cfg(x))]` the same as `#[doc(inline)]
  #[doc(cfg(x))]`. Previously, the cfg would be ignored.
- Pass the cfg predicate through to rustc_expand to be validated

Technically this is a breaking change, but doc_cfg is still nightly so I don't think it matters.

Fixes rust-lang#84437.

r? `@petrochenkov`

…nkov

Fix#84467 linker_args with --target=sparcv9-sun-solaris

Trying to cross-compile for sparcv9-sun-solaris
getting a error message for -zignore

Introduced when -z -ignore was seperated here
22d0ab0

No formatting done

Reproduce

``` bash
rustup target add sparcv9-sun-solaris
cargo new --bin hello && cd hello && cargo run --target=sparcv9-sun-solaris
```

config.toml

[target.sparcv9-sun-solaris]
linker = "gcc"

Simplify chdir implementation and minimize unsafe block

…trochenkov

Deduplicate native libs before they are passed to the linker

Stop spamming the linker with the same native library over and over again, if they directly follow from each other. This would help prevent [this situation](MSxDOS/ntapi#2).

Issue rust-lang#38460 has been open since 2016 so I think it's worth making an incomplete fix that at least addresses the most common symptom and without otherwise changing how Rust handles native libs. This PR is intended to be easy to revert (if necessary) when a more permanent fix is implemented.

…nts, r=tmandry

Report coverage `0` of dead blocks

Fixes: rust-lang#84018

With `-Z instrument-coverage`, coverage reporting of dead blocks
(for example, blocks dropped because a conditional branch is dropped,
based on const evaluation) is now supported.

If `instrument-coverage` is enabled, `simplify::remove_dead_blocks()`
finds all dropped coverage `Statement`s and adds their `code_region`s as
`Unreachable` coverage `Statement`s to the `START_BLOCK`, so they are
still included in the coverage map.

Check out the resulting changes in the test coverage reports in this PR.

I also addressed an outstanding issue/request to move coverage tests from run-make-fulldeps to run-make (in commit 2).

Fixes: rust-lang#83830

r? `@tmandry`
cc: `@wesleywiser`

…nkov

Reduce duplication in `impl_dep_tracking_hash` macros

Cherry-picked from rust-lang#84234 since it will be a while until it lands.

Account for unsatisfied bounds in E0599

Fix rust-lang#84769, follow up to rust-lang#84499, rust-lang#83667.

…olnay

use else if in std library

Decreases indentation and improves readability