Commit Graph

720 Commits

Author SHA1 Message Date
Vadim Petrochenkov
b6ac576487 rustc_interface: Dismantle register_plugins query 2023-08-07 19:33:23 +08:00
Camille GILLOT
7c34f1a8d8 Make MissingDoc a module lint. 2023-08-04 16:09:14 +00:00
Camille GILLOT
817f45f7bf Querify clashing_extern_declarations lint. 2023-08-04 16:09:13 +00:00
klensy
31630859cc replace atty crate with std's isTerminal 2023-07-26 18:09:50 +03:00
bors
bd1ae282f1 Auto merge of #113893 - mdibaiee:type-name-spill-flag, r=compiler-errors
new unstable option: -Zwrite-long-types-to-disk

This option guards the logic of writing long type names in files and instead using short forms in error messages in rustc_middle/ty/error behind a flag. The main motivation for this change is to disable this behaviour when running ui tests.

This logic can be triggered by running tests in a directory that has a long enough path, e.g. /my/very-long-path/where/rust-codebase/exists/

This means ui tests can fail depending on how long the path to their file is.

Some ui tests actually rely on this behaviour for their assertions, so for those we enable the flag manually.
2023-07-26 00:46:06 +00:00
Mahdi Dibaiee
b2d052b22d write-long-types-to-disk: update tests 2023-07-25 12:08:44 +01:00
Mahdi Dibaiee
8df39667dc new unstable option: -Zwrite-long-types-to-disk
This option guards the logic of writing long type names in files and
instead using short forms in error messages in rustc_middle/ty/error
behind a flag. The main motivation for this change is to disable this
behaviour when running ui tests.

This logic can be triggered by running tests in a directory that has a
long enough path, e.g. /my/very-long-path/where/rust-codebase/exists/

This means ui tests can fail depending on how long the path to their
file is.

Some ui tests actually rely on this behaviour for their assertions,
so for those we enable the flag manually.
2023-07-24 12:25:05 +01:00
David Tolnay
5bbf0a8306
Revert "Auto merge of #113166 - moulins:ref-niches-initial, r=oli-obk"
This reverts commit 557359f925, reversing
changes made to 1e6c09a803.
2023-07-21 22:35:57 -07:00
bors
557359f925 Auto merge of #113166 - moulins:ref-niches-initial, r=oli-obk
Prototype: Add unstable `-Z reference-niches` option

MCP: rust-lang/compiler-team#641
Relevant RFC: rust-lang/rfcs#3204

This prototype adds a new `-Z reference-niches` option, controlling the range of valid bit-patterns for reference types (`&T` and `&mut T`), thereby enabling new enum niching opportunities. Like `-Z randomize-layout`, this setting is crate-local; as such, references to built-in types (primitives, tuples, ...) are not affected.

The possible settings are (here, `MAX` denotes the all-1 bit-pattern):
| `-Z reference-niches=` | Valid range |
|:---:|:---:|
| `null` (the default) | `1..=MAX` |
| `size` | `1..=(MAX- size)` |
| `align` | `align..=MAX.align_down_to(align)` |
| `size,align` | `align..=(MAX-size).align_down_to(align)` |

------

This is very WIP, and I'm not sure the approach I've taken here is the best one, but stage 1 tests pass locally; I believe this is in a good enough state to unleash this upon unsuspecting 3rd-party code, and see what breaks.
2023-07-21 15:00:36 +00:00
Matthias Krüger
2734b5ada9
Rollup merge of #113723 - khei4:khei4/llvm-stats, r=oli-obk,nikic
Resurrect: rustc_llvm: Add a -Z `print-codegen-stats` option to expose LLVM statistics.

This resurrects PR https://github.com/rust-lang/rust/pull/104000, which has sat idle for a while. And I want to see the effect of stack-move optimizations on LLVM (like https://reviews.llvm.org/D153453) :).

I have applied the changes requested by `@oli-obk` and `@nagisa`  https://github.com/rust-lang/rust/pull/104000#discussion_r1014625377 and https://github.com/rust-lang/rust/pull/104000#discussion_r1014642482 in the latest commits.

r? `@oli-obk`

-----

LLVM has a neat [statistics](https://llvm.org/docs/ProgrammersManual.html#the-statistic-class-stats-option) feature that tracks how often optimizations kick in. It's very handy for optimization work. Since we expose the LLVM pass timings, I thought it made sense to expose the LLVM statistics too.

-----
(Edit: fix broken link
(Edit2: fix segmentation fault and use malloc

If `rustc` is built with
```toml
[llvm]
assertions = true
```
Then you can see like
```
rustc +stage1 -Z print-codegen-stats -C opt-level=3  tmp.rs
===-------------------------------------------------------------------------===
                          ... Statistics Collected ...
===-------------------------------------------------------------------------===
         3 aa                           - Number of MayAlias results
       193 aa                           - Number of MustAlias results
       531 aa                           - Number of NoAlias results
...
```

And the current default build emits only
```
$ rustc +stage1 -Z print-codegen-stats -C opt-level=3  tmp.rs
===-------------------------------------------------------------------------===
                          ... Statistics Collected ...
===-------------------------------------------------------------------------===
$
```
This might be better to emit the message to tell assertion flag necessity, but now I can't find how to do that...
2023-07-21 06:52:27 +02:00
Moulins
8b847ef734 add crate-local -Z reference_niches unstable flag (does nothing for now) 2023-07-21 03:31:45 +02:00
Esteban Küber
8eb5843a59 On nightly, dump ICE backtraces to disk
Implement rust-lang/compiler-team#578.

When an ICE is encountered on nightly releases, the new rustc panic
handler will also write the contents of the backtrace to disk. If any
`delay_span_bug`s are encountered, their backtrace is also added to the
file. The platform and rustc version will also be collected.
2023-07-19 14:10:07 +00:00
khei4
4d307c4822 print on rustc_codegen_llvm and rename malloc and cpy c_char 2023-07-17 00:37:52 +09:00
Patrick Walton
2d47816cba rustc_llvm: Add a -Z print-llvm-stats option to expose LLVM statistics.
LLVM has a neat [statistics] feature that tracks how often optimizations kick
in. It's very handy for optimization work. Since we expose the LLVM pass
timings, I thought it made sense to expose the LLVM statistics too.

[statistics]: https://llvm.org/docs/ProgrammersManual.html#the-statistic-class-stats-option
2023-07-16 22:56:04 +09:00
bors
4124617c6e Auto merge of #113606 - jyn514:parallel-compiler-cleanup, r=cjgillot
Don't require each rustc_interface tool to opt-in to parallel_compiler

Previously, forgetting to call `interface::set_thread_safe_mode` would cause the following ICE:
```
thread 'rustc' panicked at 'uninitialized dyn_thread_safe mode!', /rustc/dfe0683138de0959b6ab6a039b54d9347f6a6355/compiler/rustc_data_structures/src/sync.rs:74:18
```

This calls `set_thread_safe_mode` in `interface::run_compiler` to avoid requiring it in the caller.

Fixes `tests/run-make-fulldeps/issue-19371` when parallel-compiler is enabled.

r? `@SparrowLii` cc https://github.com/rust-lang/rust/issues/75760
2023-07-15 22:23:05 +00:00
Mark Rousskov
cc907f80b9 Re-format let-else per rustfmt update 2023-07-12 21:49:27 -04:00
jyn
d52eb4f99a Don't require each rustc_interface tool to opt-in to parallel_rustc support
Previously, forgetting to call `interface::set_thread_safe_mode` would cause the following ICE:
```
thread 'rustc' panicked at 'uninitialized dyn_thread_safe mode!', /rustc/dfe0683138de0959b6ab6a039b54d9347f6a6355/compiler/rustc_data_structures/src/sync.rs:74:18
```

This calls `set_thread_safe_mode` in `interface::run_compiler` to avoid requiring it in the caller.

Fixes `tests/run-make-fulldeps/issue-19371` when parallel-compiler is enabled.
2023-07-11 22:55:23 -05:00
Michael Goulet
810fbf086d Remove chalk from the compiler 2023-07-03 21:40:04 +00:00
Rémy Rakic
0fb80715bb use LinkSelfContained for -C link-self-contained 2023-06-30 21:01:38 +00:00
bors
8882507bc7 Auto merge of #112708 - flip1995:clippy-freezing-pc-with-ice, r=oli-obk
Avoid calling queries during query stack printing

This has the side effect, that when Clippy should ICE (during an EarlyPass?) it will fill up the RAM with 2 GB/s and then freezes my Laptop. This is blocking the Clippy sync and might give some people really bad experiences, so this should be merged ASAP.

r? `@cjgillot`
cc `@Zoxc`

I only commented this on [Zulip](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.60try_print_query_stack.60.20has.20.60ImplicitCtx.60.20during.20.60EarlyPass.60/near/363926180). I should've left a comment on the PR as well. My bad.
2023-06-28 09:40:07 +00:00
许杰友 Jieyou Xu (Joe)
cef812bd95
Provide more context for rustc +nightly -Zunstable-options on stable 2023-06-27 23:23:33 +08:00
Oli Scherer
b0142f603d
Avoid calling queries during query stack printing 2023-06-27 16:12:07 +02:00
Nicholas Nethercote
5dd7550a08 Avoid Lrc<Box<dyn CodegenBackend>>.
Because `Lrc<Box<T>>` is silly. (Clippy warns about `Rc<Box<T>>` and
`Arc<Box<T>>`, and it would warn here if (a) we used Clippy with rustc,
and (b) Clippy knew about `Lrc`.)
2023-06-22 09:18:09 +10:00
Nicholas Nethercote
1da1348924 Remove Queries::ongoing_codegen.
There's no need to store it in `Queries`. We can just use a local
variable, because it's always used shortly after it's produced.

The commit also removes the `tcx.analysis()` call in `ongoing_codegen`,
because it's easy to ensure that's done beforehand.

All this makes the dataflow within `run_compiler` easier to follow, at
the cost of making one test slightly more verbose, which I think is a
good tradeoff.
2023-06-21 11:29:45 +10:00
Ben Kimock
0a1fa411ed Remove comments from mir-opt MIR dumps 2023-06-15 15:19:11 -04:00
Maybe Waffle
8e6a193946 Tweak names and docs for vtable stats 2023-06-13 12:07:12 +00:00
Maybe Waffle
5008a08acf Simplify code as suggested by the review 2023-06-13 11:46:40 +00:00
Maybe Waffle
f2545fb225 Collect VTable stats & add -Zprint-vtable-sizes 2023-06-12 15:58:35 +00:00
bors
343ad6f059 Auto merge of #111626 - pjhades:output, r=b-naber
Write to stdout if `-` is given as output file

With this PR, if `-o -` or `--emit KIND=-` is provided, output will be written to stdout instead. Binary output (those of type `obj`, `llvm-bc`, `link` and `metadata`) being written this way will result in an error unless stdout is not a tty. Multiple output types going to stdout will trigger an error too, as they will all be mixded together.

This implements https://github.com/rust-lang/compiler-team/issues/431

The idea behind the changes is to introduce an `OutFileName` enum that represents the output - be it a real path or stdout - and to use this enum along the code paths that handle different output types.
2023-06-09 09:45:40 +00:00
Andrew Xie
54d7b327e5 Removed stable/unstable sort arg from into_sorted_stable_ord, fixed a few misc issues, added collect to UnordItems 2023-06-08 00:38:50 -04:00
Jing Peng
9b1a1e1d95 Write to stdout if - is given as output file
If `-o -` or `--emit KIND=-` is provided, output will be written
to stdout instead. Binary output (`obj`, `llvm-bc`, `link` and
`metadata`) being written this way will result in an error unless
stdout is not a tty. Multiple output types going to stdout will
trigger an error too, as they will all be mixded together.
2023-06-06 17:53:29 -04:00
Andrew Xie
1be19f710c Switched some uses to UnordMap 2023-06-04 21:55:30 -04:00
clubby789
f97fddab91 Ensure Fluent messages are in alphabetical order 2023-05-25 23:49:35 +00:00
Maybe Waffle
e2b953063d Don't leak the function that is called on drop 2023-05-23 14:53:36 +00:00
bors
17a681000b Auto merge of #111641 - michaelwoerister:debugger-visualizer-fixes, r=cjgillot
Fix dependency tracking for debugger visualizers

This PR fixes dependency tracking for debugger visualizer files by changing the `debugger_visualizers` query to an `eval_always` query that scans the AST while it is still available. This way the set of visualizer files is already available when dep-info is emitted. Since the query is turned into an `eval_always` query, dependency tracking will now reliably detect changes to the visualizer script files themselves.

TODO:
 - [x] perf.rlo
 - [x] Needs a bit more documentation in some places
 - [x] Needs regression test for the incr. comp. case

Fixes https://github.com/rust-lang/rust/issues/111226
Fixes https://github.com/rust-lang/rust/issues/111227
Fixes https://github.com/rust-lang/rust/issues/111295

r? `@wesleywiser`
cc `@gibbyfree`
2023-05-19 11:30:44 +00:00
bors
c9dc55d05c Auto merge of #111345 - jyn514:cfg-release-caching, r=cjgillot,est31
Only depend on CFG_VERSION in rustc_interface

This avoids having to rebuild the whole compiler on each commit when `omit-git-hash = false`.

cc https://github.com/rust-lang/rust/issues/76720 - this won't fix it, and I'm not suggesting we turn this on by default, but it will make it less painful for people who do have `omit-git-hash` on as a workaround.
2023-05-18 21:45:02 +00:00
Dylan DPC
08efb9d652
Rollup merge of #111633 - nnethercote:avoid-ref-format, r=WaffleLapkin
Avoid `&format("...")` calls in error message code.

Some error message cleanups. Best reviewed one commit at a time.

r? `@davidtwco`
2023-05-18 10:52:35 +05:30
jyn
d5f2b8e5c6 Only depend on CFG_VERSION in rustc_interface
this avoids having to rebuild the whole compiler on each commit when
`omit-git-hash = false`.
2023-05-17 23:54:21 -05:00
Michael Woerister
a7d48800f9 Turn debugger_visualizers from feed- into regular query. 2023-05-16 18:50:36 +02:00
Michael Woerister
7f01893900 Fix dependency tracking for debugger visualizers 2023-05-16 18:50:26 +02:00
bors
b652d9a0fd Auto merge of #108062 - Zoxc:spec-incr, r=cjgillot
Specialize query execution for incremental and non-incremental

This specializes query execution for incremental and non-incremental by passing in a separate `dyn QueryEngine` types, taking advantage of the virtual dispatch to avoid a branch. This ends up duplicating `try_execute_query`, hopefully the compile time cost of that is relatively low.

This is a performance improvement for the non-incremental path:
<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check</td><td align="right">1.8420s</td><td align="right">1.8331s</td><td align="right"> -0.48%</td></tr><tr><td>🟣 <b>hyper</b>:check</td><td align="right">0.2652s</td><td align="right">0.2631s</td><td align="right"> -0.78%</td></tr><tr><td>🟣 <b>regex</b>:check</td><td align="right">1.0161s</td><td align="right">1.0062s</td><td align="right"> -0.98%</td></tr><tr><td>🟣 <b>syn</b>:check</td><td align="right">1.6408s</td><td align="right">1.6197s</td><td align="right">💚  -1.28%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check</td><td align="right">6.3939s</td><td align="right">6.3558s</td><td align="right"> -0.60%</td></tr><tr><td>Total</td><td align="right">11.1580s</td><td align="right">11.0780s</td><td align="right"> -0.72%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">0.9918s</td><td align="right"> -0.82%</td></tr></table>

The incremental path is more neutral:
<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check:initial</td><td align="right">2.2210s</td><td align="right">2.2227s</td><td align="right"> 0.08%</td></tr><tr><td>🟣 <b>hyper</b>:check:initial</td><td align="right">0.3441s</td><td align="right">0.3443s</td><td align="right"> 0.05%</td></tr><tr><td>🟣 <b>regex</b>:check:initial</td><td align="right">1.2919s</td><td align="right">1.2877s</td><td align="right"> -0.33%</td></tr><tr><td>🟣 <b>syn</b>:check:initial</td><td align="right">2.0749s</td><td align="right">2.0721s</td><td align="right"> -0.14%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check:initial</td><td align="right">7.9266s</td><td align="right">7.9206s</td><td align="right"> -0.07%</td></tr><tr><td>Total</td><td align="right">13.8585s</td><td align="right">13.8474s</td><td align="right"> -0.08%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">0.9992s</td><td align="right"> -0.08%</td></tr></table>

r? `@cjgillot`
2023-05-16 16:02:53 +00:00
Nicholas Nethercote
01e33a3600 Avoid &format("...") calls in error message code.
Error message all end up passing into a function as an `impl
Into<{D,Subd}iagnosticMessage>`. If an error message is creatd as
`&format("...")` that means we allocate a string (in the `format!`
call), then take a reference, and then clone (allocating again) the
reference to produce the `{D,Subd}iagnosticMessage`, which is silly.

This commit removes the leading `&` from a lot of these cases. This
means the original `String` is moved into the
`{D,Subd}iagnosticMessage`, avoiding the double allocations. This
requires changing some function argument types from `&str` to `String`
(when all arguments are `String`) or `impl
Into<{D,Subd}iagnosticMessage>` (when some arguments are `String` and
some are `&str`).
2023-05-16 17:59:56 +10:00
John Kåre Alsaker
fff20a703d Move expansion of query macros in rustc_middle to rustc_middle::query 2023-05-15 08:49:13 +02:00
John Kåre Alsaker
882a9684f9 Specialize query execution for incremental and non-incremental 2023-05-14 21:53:05 +02:00
bors
8e8116cfe5 Auto merge of #108638 - Zoxc:erase-query-values-map, r=cjgillot
Use dynamic dispatch for queries

This replaces most concrete query values `V` with `MaybeUninit<[u8; { size_of::<V>() }]>` reducing the code instantiated by queries. The compile time of `rustc_query_impl` is reduced by 27%. It is an alternative to https://github.com/rust-lang/rust/pull/107937 which uses unstable const generics while this uses a `EraseType` trait which maps query values to their erased variant.

This is achieved by introducing an `Erased` type which does sanity check with `cfg(debug_assertions)`. The query caches gets instantiated with these erased types leaving the code in `rustc_query_system` unaware of them. `rustc_query_system` is changed to use instances of `QueryConfig` so that `rustc_query_impl` can pass in `DynamicConfig` which holds a pointer to a virtual table.

<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check</td><td align="right">1.7055s</td><td align="right">1.6949s</td><td align="right"> -0.62%</td></tr><tr><td>🟣 <b>hyper</b>:check</td><td align="right">0.2547s</td><td align="right">0.2528s</td><td align="right"> -0.73%</td></tr><tr><td>🟣 <b>regex</b>:check</td><td align="right">0.9590s</td><td align="right">0.9553s</td><td align="right"> -0.39%</td></tr><tr><td>🟣 <b>syn</b>:check</td><td align="right">1.5457s</td><td align="right">1.5440s</td><td align="right"> -0.11%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check</td><td align="right">5.9092s</td><td align="right">5.9009s</td><td align="right"> -0.14%</td></tr><tr><td>Total</td><td align="right">10.3741s</td><td align="right">10.3479s</td><td align="right"> -0.25%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">0.9960s</td><td align="right"> -0.40%</td></tr></table>

<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check:initial</td><td align="right">2.0605s</td><td align="right">2.0575s</td><td align="right"> -0.15%</td></tr><tr><td>🟣 <b>hyper</b>:check:initial</td><td align="right">0.3218s</td><td align="right">0.3216s</td><td align="right"> -0.07%</td></tr><tr><td>🟣 <b>regex</b>:check:initial</td><td align="right">1.1848s</td><td align="right">1.1839s</td><td align="right"> -0.07%</td></tr><tr><td>🟣 <b>syn</b>:check:initial</td><td align="right">1.9409s</td><td align="right">1.9376s</td><td align="right"> -0.17%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check:initial</td><td align="right">7.3105s</td><td align="right">7.2928s</td><td align="right"> -0.24%</td></tr><tr><td>Total</td><td align="right">12.8185s</td><td align="right">12.7935s</td><td align="right"> -0.20%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">0.9986s</td><td align="right"> -0.14%</td></tr></table>

<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check:unchanged</td><td align="right">0.4606s</td><td align="right">0.4617s</td><td align="right"> 0.24%</td></tr><tr><td>🟣 <b>hyper</b>:check:unchanged</td><td align="right">0.1335s</td><td align="right">0.1336s</td><td align="right"> 0.08%</td></tr><tr><td>🟣 <b>regex</b>:check:unchanged</td><td align="right">0.3324s</td><td align="right">0.3346s</td><td align="right"> 0.65%</td></tr><tr><td>🟣 <b>syn</b>:check:unchanged</td><td align="right">0.6268s</td><td align="right">0.6307s</td><td align="right"> 0.64%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check:unchanged</td><td align="right">1.8248s</td><td align="right">1.8508s</td><td align="right">💔  1.43%</td></tr><tr><td>Total</td><td align="right">3.3779s</td><td align="right">3.4113s</td><td align="right"> 0.99%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">1.0061s</td><td align="right"> 0.61%</td></tr></table>

It's based on https://github.com/rust-lang/rust/pull/108167.

r? `@cjgillot`
2023-05-14 13:47:01 +00:00
bors
dd8ec9c88d Auto merge of #107586 - SparrowLii:parallel-query, r=cjgillot
Introduce `DynSend` and `DynSync` auto trait for parallel compiler

part of parallel-rustc #101566

This PR introduces `DynSend / DynSync` trait and `FromDyn / IntoDyn` structure in rustc_data_structure::marker. `FromDyn` can dynamically check data structures for thread safety when switching to parallel environments (such as calling `par_for_each_in`). This happens only when `-Z threads > 1` so it doesn't affect single-threaded mode's compile efficiency.

r? `@cjgillot`
2023-05-13 13:47:53 +00:00
Matthias Krüger
aa9adf457b
Rollup merge of #111292 - Urgau:check-cfg-issue-111291, r=petrochenkov
Fix mishandled `--check-cfg` arguments order

This PR fixes a bug in `--check-cfg` where the order of `--check-cfg=names(a)` and `--check-cfg=values(a,…)` would trip the compiler.

Fixes https://github.com/rust-lang/rust/issues/111291
cc `@taiki-e` `@petrochenkov`
2023-05-11 07:05:27 +02:00
Urgau
f4ca42f573 Fix --check-cfg bug with args order when parsing 2023-05-06 18:40:47 +02:00
bors
333b920fee Auto merge of #109421 - mhammerly:extern-force-option, r=petrochenkov
Add `force` option for `--extern` flag

When `--extern force:foo=libfoo.so` is passed to `rustc` and `foo` is not actually used in the crate, ~inject an `extern crate foo;` statement into the AST~ force it to be resolved anyway in `CrateLoader::postprocess()`. This allows you to, for instance, inject a `#[panic_handler]` implementation into a `#![no_std]` crate without modifying its source so that it can be built as a `dylib`. It may also be useful for `#![panic_runtime]` or `#[global_allocator]`/`#![default_lib_allocator]` implementations.

My work previously involved integrating Rust into an existing C/C++ codebase which was built with Buck and shipped on, among other platforms, Android. When targeting Android, Buck builds all "native" code with shared linkage* so it can be loaded from Java/Kotlin. My project was not itself `#![no_std]`, but many of our dependencies were, and they would fail to build with shared linkage due to a lack of a panic handler. With this change, that project can add the new `force` option to the `std` dependency it already explicitly provides to every crate to solve this problem.

*This is an oversimplification - Buck has a couple features for aggregating dependencies into larger shared libraries, but none that I think sustainably solve this problem.

~The AST injection happens after macro expansion around where we similarly inject a test harness and proc-macro harness. The resolver's list of actually-used extern flags is populated during macro expansion, and if any of our `--extern` arguments have the `force` option and weren't already used, we inject an `extern crate` statement for them. The injection logic was added in `rustc_builtin_macros` as that's where similar injections for tests, proc-macros, and std/core already live.~

(New contributor - grateful for feedback and guidance!)
2023-05-06 11:24:37 +00:00
SparrowLii
089a38880b correct literals for dyn thread safe 2023-05-06 09:34:53 +08:00