privacy: Use common `DefId` visiting infrastructure for all privacy visitors
One repeating pattern in privacy checking is going through a type, visiting all `DefId`s inside it and doing something with them.
This is the case because visibilities and reachabilities are attached to `DefId`s.
Previously various privacy visitors visited types slightly differently using their own methods, with most recently written `TypePrivacyVisitor` being the "gold standard".
This mostly worked okay, but differences could manifest in overly conservative reachability analysis, some errors being reported twice, some private-in-public lints (not errors) being wrongly reported or not reported.
This PR does something that I wanted to do since https://github.com/rust-lang/rust/pull/32674#discussion_r58291608 - factoring out the common visiting logic!
Now all the common logic is contained in `struct DefIdVisitorSkeleton`, with specific privacy visitors deciding only what to do with visited `DefId`s (via `trait DefIdVisitor`).
A bunch of cleanups is also applied in the process.
This area is somewhat tricky due to lots of easily miss-able details, but thankfully it's was well covered by tests in https://github.com/rust-lang/rust/pull/46083 and previous PRs, so I'm relatively sure in the refactoring correctness.
Fixes https://github.com/rust-lang/rust/pull/56837#discussion_r241962239 in particular.
Also this will help with implementing https://github.com/rust-lang/rust/issues/48054.
Add `-Z instrument-mcount`
This flag inserts `mcount` function call to the beginning of every function
after inline processing. So tracing tools like uftrace [1] (or ftrace for
Linux kernel modules) have a chance to examine function calls.
It is similar to the `-pg` flag provided by gcc or clang, but without
generating a `__gmon_start__` function for executables. If a program
runs without being traced, no `gmon.out` will be written to disk.
Under the hood, it simply adds `"instrument-function-entry-inlined"="mcount"`
attribute to every function. The `post-inline-ee-instrument` LLVM pass does
the actual job.
[1]: https://github.com/namhyung/uftrace
There are three problems with the nolink-with-link-args test:
* The test fails when using MSVC. It's caused by the `linker-flavor=ld` flag which was added in #46291.
* In its comment, this test tests that "link_args are indeed passed when nolink is specified", but the `nolink` attribute has been removed [a long time ago](https://github.com/rust-lang/rust/pull/12826).
* Pattern has a small typo.
At first I was going to completely remove this test, but there is [a closed pull request for that](https://github.com/rust-lang/rust/pull/21090).
So:
* rename the file as suggested in the closed PR
* adjust the comment
* fix typo in the pattern
* add `ignore-msvc`.
This flag inserts `mcount` function call to the beginning of every function
after inline processing. So tracing tools like uftrace [1] (or ftrace for
Linux kernel modules) have a chance to examine function calls.
It is similar to the `-pg` flag provided by gcc or clang, but without
generating a `__gmon_start__` function for executables. If a program
runs without being traced, no `gmon.out` will be written to disk.
Under the hood, it simply adds `"instrument-function-entry-inlined"="mcount"`
attribute to every function. The `post-inline-ee-instrument` LLVM pass does
the actual job.
[1]: https://github.com/namhyung/uftrace
submodules: update clippy from f7bdf500 to 39bd8449
Fixes clippy toolstate
Changes:
````
UI test cleanup: Extract iter_skip_next from methods.rs
Update test output after rebase
Remove false negatives from known problems
Implement use_self for tuple structs
Document known problems
rustup https://github.com/rust-lang/rust/pull/56225/
Remove unnecessary `use` statements after `cargo fix`
Apply cargo fix --edition-idioms fixes
Use match ergonomics for booleans lint
Use match ergonomics for block_in_if_condition lint
Use match ergonomics for bit_mask lint
Use match ergonomics for attrs lint
Use match ergonomics for assign_ops lint
Use match ergonomics for artithmetic lint
Use match ergonomics for approx_const lint
Remove crate:: prefixes from crate paths
Support array indexing expressions in unused write to a constant
Mark writes to constants as side-effect-less
Update README local run command to remove syspath
Remove unsafe from consts clippy lints
Fix formatting
Merge new_without_default_derive into new_without_default
Only print out question_mark lint when it actually triggered
Add failing test
Reinserted commata
Recomend `.as_ref()?` in certain situations
Deduplicate some code?
````
r? @oli-obk or anyone else
Changes:
````
UI test cleanup: Extract iter_skip_next from methods.rs
Update test output after rebase
Remove false negatives from known problems
Implement use_self for tuple structs
Document known problems
rustup https://github.com/rust-lang/rust/pull/56225/
Remove unnecessary `use` statements after `cargo fix`
Apply cargo fix --edition-idioms fixes
Use match ergonomics for booleans lint
Use match ergonomics for block_in_if_condition lint
Use match ergonomics for bit_mask lint
Use match ergonomics for attrs lint
Use match ergonomics for assign_ops lint
Use match ergonomics for artithmetic lint
Use match ergonomics for approx_const lint
Remove crate:: prefixes from crate paths
Support array indexing expressions in unused write to a constant
Mark writes to constants as side-effect-less
Update README local run command to remove syspath
Remove unsafe from consts clippy lints
Fix formatting
Merge new_without_default_derive into new_without_default
Only print out question_mark lint when it actually triggered
Add failing test
Reinserted commata
Recomend `.as_ref()?` in certain situations
Deduplicate some code?
````
When resolving Fn traits, the compiler failed to take into account
overloaded implementations. To resolve this, we inform the trait dispatch
code that the arguments will becoming as a tuple of correct arity.
