Add a sparc-unknown-none-elf target.
# `sparc-unknown-none-elf`
**Tier: 3**
Rust for bare-metal 32-bit SPARC V7 and V8 systems, e.g. the Gaisler LEON3.
## Target maintainers
- Jonathan Pallant, `jonathan.pallant@ferrous-systems.com`, https://ferrous-systems.com
## Requirements
> Does the target support host tools, or only cross-compilation?
Only cross-compilation.
> Does the target support std, or alloc (either with a default allocator, or if the user supplies an allocator)?
Only tested with `libcore` but I see no reason why you couldn't also support `liballoc`.
> Document the expectations of binaries built for the target. Do they assume
specific minimum features beyond the baseline of the CPU/environment/etc? What
version of the OS or environment do they expect?
Tested by linking with a standard SPARC bare-metal toolchain - specifically I used the [BCC2] toolchain from Gaisler (both GCC and clang variants, both pre-compiled for x64 Linux and compiling my own SPARC GCC from source to run on `aarch64-apple-darwin`).
The target is set to use the lowest-common-denominator `SPARC V7` architecture (yes, they started at V7 - see [Wikipedia](https://en.wikipedia.org/wiki/SPARC#History)).
[BCC2]: https://www.gaisler.com/index.php/downloads/compilers
> Are there notable `#[target_feature(...)]` or `-C target-feature=` values that
programs may wish to use?
`-Ctarget-cpu=v8` adds the instructions added in V8.
`-Ctarget-cpu=leon3` adds the V8 instructions and sets up scheduling to suit the Gaisler LEON3.
> What calling convention does `extern "C"` use on the target?
I believe this is defined by the SPARC architecture reference manuals and V7, V8 and V9 are all compatible.
> What format do binaries use by default? ELF, PE, something else?
ELF
## Building the target
> If Rust doesn't build the target by default, how can users build it? Can users
just add it to the `target` list in `config.toml`?
Yes. I did:
```toml
target = ["aarch64-apple-darwin", "sparc-unknown-none-elf"]
```
## Building Rust programs
> Rust does not yet ship pre-compiled artifacts for this target. To compile for
this target, you will either need to build Rust with the target enabled (see
"Building the target" above), or build your own copy of `core` by using
`build-std` or similar.
Correct.
## Testing
> Does the target support running binaries, or do binaries have varying
expectations that prevent having a standard way to run them?
No - it's a bare metal platform.
> If users can run binaries, can they do so in some common emulator, or do they need native
hardware?
But if you use [BCC2] as the linker, you get default memory map suitable for the LEON3, and a default BSP for the LEON3, and so you can run the binaries in the `tsim-leon3` simulator from Gaisler.
```console
$ cat .cargo/config.toml | grep runner
runner = "tsim-leon3 -c sim-commands.txt"
$ cat sim-commands.txt
run
quit
$ cargo +sparcrust run --targe=sparc-unknown-none-elf
Compiling sparc-demo-rust v0.1.0 (/work/sparc-demo-rust)
Finished dev [unoptimized + debuginfo] target(s) in 3.44s
Running `tsim-leon3 -c sim-commands.txt target/sparc-unknown-none-elf/debug/sparc-demo-rust`
TSIM3 LEON3 SPARC simulator, version 3.1.9 (evaluation version)
Copyright (C) 2023, Frontgrade Gaisler - all rights reserved.
This software may only be used with a valid license.
For latest updates, go to https://www.gaisler.com/
Comments or bug-reports to support@gaisler.com
This TSIM evaluation version will expire 2023-11-28
Number of CPUs: 2
system frequency: 50.000 MHz
icache: 1 * 4 KiB, 16 bytes/line (4 KiB total)
dcache: 1 * 4 KiB, 16 bytes/line (4 KiB total)
Allocated 8192 KiB SRAM memory, in 1 bank at 0x40000000
Allocated 32 MiB SDRAM memory, in 1 bank at 0x60000000
Allocated 8192 KiB ROM memory at 0x00000000
section: .text, addr: 0x40000000, size: 104400 bytes
section: .rodata, addr: 0x400197d0, size: 15616 bytes
section: .data, addr: 0x4001d4d0, size: 1176 bytes
read 1006 symbols
Initializing and starting from 0x40000000
Hello, this is Rust!
PANIC: PanicInfo { payload: Any { .. }, message: Some(I am a panic), location: Location { file: "src/main.rs", line: 33, col: 5 }, can_unwind: true }
Program exited normally on CPU 0.
```
> Does the target support running the Rust testsuite?
I don't think so, the testsuite requires `libstd` IIRC.
## Cross-compilation toolchains and C code
> Does the target support C code?
Yes.
> If so, what toolchain target should users use to build compatible C code? (This may match the target triple, or it may be a toolchain for a different target triple, potentially with specific options or caveats.)
I suggest [BCC2] from Gaisler. It comes in both GCC and Clang variants.
Use u64 for incr comp allocation offsets
Fixes https://github.com/rust-lang/rust/issues/76037
Fixes https://github.com/rust-lang/rust/issues/95780
Fixes https://github.com/rust-lang/rust/issues/111613
These issues are all reporting ICEs caused by using `u32` to store offsets to allocations in the incremental compilation cache. This PR aims to lift that limitation by changing the offset type in question to `u64`.
There are two perf runs in this PR. The first reports a regression, and the second does not. The changes are the same in both. I rebased the PR then did the second perf run because I noticed that the primary regression in it was very commonly seen in spurious regression reports.
I do not know what the perf run will report when this is merged. I would not be surprised to see regression or neutral, but the cachegrind diffs for the regression point at `try_mark_previous_green` which is a common source of inexplicable regressions and I don't think should be perturbed by this PR.
I'm not opposed to adding a regression test such as
```rust
fn main() {
println!("{}", [37; 1 << 30].len());
}
```
But that program takes 1 minute to compile and consumes 4.6 GB of memory then writes that much to disk. Is that a concerning amount of resource use for a test?
r? `@nnethercote`
Streamline size estimates (take 2)
This was merged in #113684 but then [something happened](https://github.com/rust-lang/rust/pull/113684#issuecomment-1636811985):
> There has been a bors issue that lead to the merge commit of this PR getting purged from master.
> You'll have to make a new PR to reapply it.
So this is exactly the same changes.
`@bors` r=wesleywiser
Add support for inherent projections in new solver
Not hard to support these, and it cuts out a really big chunk of failing UI tests with `--compare-mode=next-solver`
r? `@lcnr` (feel free to reassign, anyone can review this)
They're quite rare, and ignoring them simplifies things quite a bit, and
further reduces the number of calls to `MonoItem::size_estimate` to the
number of placed items (one per root item, and one or more per reachable
inlined item).
This means we call `MonoItem::size_estimate` (which involves a query)
less often: just once per mono item, and then once more per inline item
placement. After that we can reuse the stored value as necessary. This
means `CodegenUnit::compute_size_estimate` is cheaper.
Add Platform Support documentation for MIPS Release 6 targets
This is a follow-up to our to-announce MCP, rust-lang/compiler-team#638, where we proposed to assign several maintainers for MIPS R6 targets and was told to explain that this set of targets are experimental in nature.
This documentation describes Rust support for `mipsisa*r6*-unknown-linux-gnu*` targets (mainly `mipsisa64r6el-unknown-linux-gnuabi64`), including toolchain setup, building, and testing procedures.
Don't call `predicate_must_hold`-esque functions during fulfillment in intercrate
Fixes#113415
Given that this only happens in `translate_substs`, I don't actually think that this is something that you can weaponize, but it's still sketchy regardless.
r? `@lcnr`
Check entry type as part of item type checking.
This code is currently executed inside the root `analysis` query.
Instead, check it during `check_for_entry_fn(CRATE_DEF_ID)` to hopefully avoid some re-executions.
`CRATE_DEF_ID` is chosen by considering that entry fn are typically at crate root, so the corresponding HIR should already be in the dependencies.
Add `#[rustc_confusables]` attribute to allow targeted "no method" error suggestions on standard library types
After this PR, the standard library developer can annotate methods on e.g. `BTreeSet::push` with `#[rustc_confusables("insert")]`. When the user mistypes `btreeset.push()`, `BTreeSet::insert` will be suggested if there are no other candidates to suggest. This PR lays the foundations for contributors to add `rustc_confusables` annotations to standard library types for targeted suggestions, as specified in #59450, or to address cases such as #108437.
### Example
Assume `BTreeSet` is the standard library type:
```
// Standard library definition
#![feature(rustc_attrs)]
struct BTreeSet;
impl BTreeSet {
#[rustc_confusables("push")]
fn insert(&self) {}
}
// User code
fn main() {
let x = BTreeSet {};
x.push();
}
```
A new suggestion (which has lower precedence than suggestions for misspellings and only is shown when there are no misspellings suggestions) will be added to hint the user maybe they intended to write `x.insert()` instead:
```
error[E0599]: no method named `push` found for struct `BTreeSet` in the current scope
--> test.rs:12:7
|
3 | struct BTreeSet;
| --------------- method `push` not found for this struct
...
12 | x.push();
| ^^^^ method not found in `BTreeSet`
|
help: you might have meant to use `insert`
|
12 | x.insert();
| ~~~~~~
error: aborting due to previous error
```
Hide `compiler_builtins` in the prelude
This crate is a private implementation detail. We only need to insert it into the crate graph for linking and should not expose any of its public API.
Fixes#113533
"no method" errors on standard library types
The standard library developer can annotate methods on e.g.
`BTreeSet::push` with `#[rustc_confusables("insert")]`. When the user
mistypes `btreeset.push()`, `BTreeSet::insert` will be suggested if
there are no other candidates to suggest.
De-duplicate consecutive libs when printing native-static-libs
This PR adds a de-duplicate step just before printing the `native-static-libs`.
This step de-duplicates all the consecutive libs based only on the relevant comparison elements (this exclude spans, ast elements, ...).
Fixes https://github.com/rust-lang/rust/issues/113209
Remove `LLVMRustCoverageHashCString`
Coverage has two FFI functions for computing the hash of a byte string. One takes a ptr/len pair (`LLVMRustCoverageHashByteArray`), and the other takes a NUL-terminated C string (`LLVMRustCoverageHashCString`).
But on closer inspection, the C string version is unnecessary. The calling-side code converts a Rust `&str` into a `CString`, and the C++ code then immediately turns it back into a ptr/len string before actually hashing it. So we can just call the ptr/len version directly instead.
---
This PR also fixes a bug in the C++ declaration of `LLVMRustCoverageHashByteArray`. It should be `size_t`, since that's what is declared and passed on the Rust side, and it's what `StrRef`'s constructor expects to receive on the callee side.
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
Remove unneeded handling for `ExternalLocation::Unknown` in rustdoc render context
Should fix perf regression introduced in https://github.com/rust-lang/rust/pull/113623.
r? `@lqd`
Rollup of 6 pull requests
Successful merges:
- #113625 (Structurally normalize in selection)
- #113644 (misc bootstrap cleanups)
- #113663 (Implement "items do not inherit unsafety" note for THIR unsafeck)
- #113683 (remove outdated `FIXME`s in bootstrap internals)
- #113709 (rustdoc: use src consistently over source in CSS/JS)
- #113724 (Migrate GUI colors test to original CSS color format)
r? `@ghost`
`@rustbot` modify labels: rollup
rustdoc: use src consistently over source in CSS/JS
The two terms have been used, inconsistently, in closely related spots like the `src/` directory vs `source-files.js`, and with things like `src-sidebar-toggle` vs the `source-sidebar`. This PR changes most use of `source` to `src` instead (except the localStorage configuration variables, which would be very complicated to migrate).
It also renames `.srclink` to `.src`. This is mostly aiming to cut out one of those many little peanut-butter bits of bloat, and is consistent with how other link classes are done (like how you have `a.mod` stylesheet rules, but there's also a `mod` class put on the body tag).
Matthias Krüger