This option was introduced three years ago, but it's never been
meaningfully used, and `default` is the only acceptable value.
Also, I think the `Partition` trait presents an interface that is too
closely tied to the existing strategy and would probably be wrong for
other strategies. (My rule of thumb is to not make something generic
until there are at least two instances of it, to avoid this kind of
problem.)
Also, I don't think providing multiple partitioning strategies to the
user is a good idea, because the compiler already has enough obscure
knobs.
This commit removes the option, along with the `Partition` trait, and
the `Partitioner` and `DefaultPartitioning` types. I left the existing
code in `compiler/rustc_monomorphize/src/partitioning/default.rs`,
though I could be persuaded that moving it into
`compiler/rustc_monomorphize/src/partitioning/mod.rs` is better.
I find that these structs obfuscate the code. Removing them and just
passing the individual fields around makes the `Partition` method
signatures a little longer, but makes the data flow much clearer. E.g.
- `codegen_units` is mutable all the way through.
- `codegen_units`'s length is changed by `merge_codegen_units`, but only
the individual elements are changed by `place_inlined_mono_items` and
`internalize_symbols`.
- `roots`, `internalization_candidates`, and `mono_item_placements` are
all immutable after creation, and all used by just one of the four
methods.
Three of the four methods in `DefaultPartitioning` are defined in
`default.rs`. But `merge_codegen_units` is defined in a separate module,
`merging`, even though it's less than 100 lines of code and roughly the
same size as the other three methods. (Also, the `merging` module
currently sits alongside `default`, when it should be a submodule of
`default`, adding to the confusion.)
In #74275 this explanation was given:
> I pulled this out into a separate module since it seemed like we might
> want a few different merge algorithms to choose from.
But in the three years since there have been no additional merging
algorithms, and there is no mechanism for choosing between different
merging algorithms. (There is a mechanism,
`-Zcgu-partitioning-strategy`, for choosing between different
partitioning strategies, but the merging algorithm is just one piece of
a partitioning strategy.)
This commit merges `merging` into `default`, making the code easier to
navigate and read.
- Pass a slice instead of an iterator to `debug_dump`.
- For each CGU set, print: the number of CGUs, the max and min size, and
the ratio of the max and min size (which indicates how evenly sized
they are).
- Print a `FINAL` entry, showing the absolute final results.
incremental: migrate diagnostics
- Apply the diagnostic migration lints to more functions on `Session`, namely: `span_warn`, `span_warn_with_code`, `warn` `note_without_error`, `span_note_without_error`, `struct_note_without_error`.
- Add impls of `IntoDiagnosticArg` for `std::io::Error`, `std::path::Path` and `std::path::PathBuf`.
- Migrate the `rustc_incremental` crate's diagnostics to translatable diagnostic structs.
r? `@compiler-errors`
cc #100717
Convert all the crates that have had their diagnostic migration
completed (except save_analysis because that will be deleted soon and
apfloat because of the licensing problem).
This allows analyzing the output programatically; for example, finding
the item with the highest `total_estimate`.
I also took the liberty of adding `untracked` tests to `rustc_session` and documentation to the unstable book for `dump-mono-items`.
Migrate rustc_monomorphize to use SessionDiagnostic
### Description
- Migrates diagnostics in `rustc_monomorphize` to use `SessionDiagnostic`
- Adds an `impl IntoDiagnosticArg for PathBuf`
### TODO / Help!
- [x] I'm having trouble figuring out how to apply an optional note. 😕 Help!?
- Resolved. It was bad docs. Fixed in https://github.com/rust-lang/rustc-dev-guide/pull/1437/files
- [x] `errors:RecursionLimit` should be `#[fatal ...]`, but that doesn't exist so it's `#[error ...]` at the moment.
- Maybe I can switch after this is merged in? --> https://github.com/rust-lang/rust/pull/100694
- Or maybe I need to manually implement `SessionDiagnostic` instead of deriving it?
- [x] How does one go about converting an error inside of [a call to struct_span_lint_hir](8064a49508/compiler/rustc_monomorphize/src/collector.rs (L917-L927))?
- [x] ~What placeholder do you use in the fluent template to refer to the value in a vector? It seems like [this code](0b79f758c9/compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs (L83-L114)) ought to have the answer (or something near it)...but I can't figure it out.~ You can't. Punted.
Fix unreachable coverage generation for inlined functions
To generate a function coverage we need at least one coverage counter,
so a coverage from unreachable blocks is retained only when some live
counters remain.
The previous implementation incorrectly retained unreachable coverage,
because it didn't account for the fact that those live counters can
belong to another function due to inlining.
Fixes#98833.
To generate a function coverage we need at least one coverage counter,
so a coverage from unreachable blocks is retained only when some live
counters remain.
The previous implementation incorrectly retained unreachable coverage,
because it didn't account for the fact that those live counters can
belong to another function due to inlining.
Move ty::print methods to Drop-based scope guards
Primary goal is reducing codegen of the TLS access for each closure, which shaves ~3 seconds of bootstrap time over rustc as a whole.
The issue here is that the logic used to determine which CGU to put the
dead function stubs in doesn't handle cases where a module is never
assigned to a CGU.
The partitioning logic also caused issues in #85461 where inline
functions were duplicated into multiple CGUs resulting in duplicate
symbols.
This commit fixes the issue by removing the complex logic used to assign
dead code stubs to CGUs and replaces it with a much simplier model: we
pick one CGU to hold all the dead code stubs. We pick a CGU which has
exported items which increases the likelihood the linker won't throw
away our dead functions and we pick the smallest to minimize the impact
on compilation times for crates with very large CGUs.
Fixes#86177Fixes#85718Fixes#79622
By changing `as_str()` to take `&self` instead of `self`, we can just
return `&str`. We're still lying about lifetimes, but it's a smaller lie
than before, where `SymbolStr` contained a (fake) `&'static str`!
