The style guide requires a trailing comma on where clause components,
but then gives an example that doesn't include one. Add the missing
trailing comma.
Add x86_64-unknown-linux-ohos target
This complements the existing `aarch64-unknown-linux-ohos` and `armv7-unknown-linux-ohos` targets.
This should be covered by the existing MCP (https://github.com/rust-lang/compiler-team/issues/568), but I can also create a new MCP if that is preferred.
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.
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.
style-guide: Fix chain example to match rustfmt behavior
The style guide gave an example of breaking a multi-line chain element
and all subsequent elements to a new line, but that same example and the
accompanying text also had several chain items stacked on the first
line. rustfmt doesn't do this, except when the rule saying to combine
```
shrt
.y()
```
into
```
shrt.y()
```
applies.
This is a bugfix to match rustfmt behavior, so it's not a breaking change, and
it just needs a ``@rust-lang/style`` reviewer to r+.
style-guide: Expand example of combinable expressions to include arrays
Arrays are allowed as combinable expressions, but none of the examples
show that.
style-guide: Clarify grammar for small patterns (not a semantic change)
The grammar as written feels ambiguous and confusing, in large part
because it uses square brackets and commas in the names of
non-terminals. Rewrite it to avoid symbols in the names of
non-terminals, and to instead wrap terminals in backquotes.
Also rename "smallntp" to "small_no_tuple" to make it self-describing.
style-guide: Document newline rules for assignment operators
The style guide gives general rules for binary operators including
assignment, and one of those rules says to put the operator on the
subsequent line; the style guide needs to explicitly state the exception
of breaking *after* assignment operators rather than before.
This is already what rustfmt does and what users do; this fixes the
style guide to match the expected default style.
The style guide gave an example of breaking a multi-line chain element
and all subsequent elements to a new line, but that same example and the
accompanying text also had several chain items stacked on the first
line. rustfmt doesn't do this, except when the rule saying to combine
```
shrt
.y()
```
into
```
shrt.y()
```
applies.
The grammar as written feels ambiguous and confusing, in large part
because it uses square brackets and commas in the names of
non-terminals. Rewrite it to avoid symbols in the names of
non-terminals, and to instead wrap terminals in backquotes.
Updates the descriptions of the various ARM targets in platform-support.md so they are a little more consistent.
For example, all instances of ARMv7 changed to ARMv7-A (as opposed to ARMv7-R and ARMv7-M).
style-guide: Narrow guidance about references and dereferencing
The style guide advises "prefer dereferencing to taking references", but
doesn't give guidance on when that "preference" should get overridden by
other considerations. Give an example of when it's fine to ignore
that advice.
style-guide: Add an example of formatting a multi-line attribute
We already say to format attributes like functions, but we didn't have
an example of formatting a multi-line attribute.
The style guide gives general rules for binary operators including
assignment, and one of those rules says to put the operator on the
subsequent line; the style guide needs to explicitly state the exception
of breaking *after* assignment operators rather than before.
This is already what rustfmt does and what users do; this fixes the
style guide to match the expected default style.
The style guide advises "prefer dereferencing to taking references", but
doesn't give guidance on when that "preference" should get overridden by
other considerations. Give an example of when it's fine to ignore
that advice.
doc: loongarch: Update maintainers
My colleague, `@zhaixiaojuan,` has been completely occupied with other matters and is no longer in charge of Rust. Consequently, I intend to update the maintainers in the platform documentation to avoid causing any disruptions for her and to ensure that relevant notifications regarding LoongArch are promptly directed to the appropriate developers.
Thanks your for contributions!
- This documentation describes the Rust support for Linux MIPS Release 6
targets.
- Also update the status of mipsisa64r6el-unknown-linux-gnuabi64i in
SUMMARY, as we have successfully built the native toolchain.
- Also fill out the description of MIPS R6 targets in SUMMARY.
style-guide: Rewrite let-else section for clarity, without changing formatting
The section as written did not cover all cases, and left some of them
implicit. Rewrite it to systematically cover all cases. Place examples
immediately following the corresponding case.
In the process, reorder to move the simplest cases first: start with
single-line and add progressively more line breaks.
This does not change the meaning of the section at all, and in
particular does not change the defined style for let-else statements.
style-guide: Add language disclaiming any effects on non-default Rust styles
Make it clear that the style guide saying "must" doesn't forbid
developers from doing differently (as though any power on this Earth
could do that) and doesn't forbid tools from allowing any particular
configuration options.
Otherwise, people might wonder (for instance) if there's a semantic difference
between "must" and "should" in the style guide, and whether tools are "allowed"
to offer configurability of something that says "must".
style-guide: Organizational and editing tweaks (no semantic changes)
I'd recommend reviewing this PR commit-by-commit; each commit is self-contained
and should be easy to review at a glance.
- style-guide: Move text about block vs visual indent to indentation section
- style-guide: Move and expand text about trailing commas
- style-guide: s/right-ward/rightward/
- style-guide: Consistently refer to rustfmt as `rustfmt`
- style-guide: Remove inaccurate statement about rustfmt
- style-guide: Define (and capitalize) "ASCIIbetically"
- style-guide: Update cargo.md for authors being optional and not recommended
- style-guide: Avoid normative recommendations for formatting tool configurability
- style-guide: Clarify advice on names matching keywords
- style-guide: Reword an awkwardly phrased recommendation (and fix a typo)
- style-guide: Rephrase a confusingly ordered, ambiguous sentence (and fix a typo)
- style-guide: Avoid hyphenating "semicolon"
- style-guide: Make link text in SUMMARY.md match the headings in the linked pages
- style-guide: Define what an item is
- style-guide: Avoid referring to the style team in the past tense
Make it clear that the style guide saying "must" doesn't forbid
developers from doing differently (as though any power on this Earth
could do that) and doesn't forbid tools from allowing any particular
configuration options.
