feat: `riscv-interrupt-{m,s}` calling conventions
Similar to prior support added for the mips430, avr, and x86 targets this change implements the rough equivalent of clang's [`__attribute__((interrupt))`][clang-attr] for riscv targets, enabling e.g.
```rust
static mut CNT: usize = 0;
pub extern "riscv-interrupt-m" fn isr_m() {
unsafe {
CNT += 1;
}
}
```
to produce highly effective assembly like:
```asm
pub extern "riscv-interrupt-m" fn isr_m() {
420003a0: 1141 addi sp,sp,-16
unsafe {
CNT += 1;
420003a2: c62a sw a0,12(sp)
420003a4: c42e sw a1,8(sp)
420003a6: 3fc80537 lui a0,0x3fc80
420003aa: 63c52583 lw a1,1596(a0) # 3fc8063c <_ZN12esp_riscv_rt3CNT17hcec3e3a214887d53E.0>
420003ae: 0585 addi a1,a1,1
420003b0: 62b52e23 sw a1,1596(a0)
}
}
420003b4: 4532 lw a0,12(sp)
420003b6: 45a2 lw a1,8(sp)
420003b8: 0141 addi sp,sp,16
420003ba: 30200073 mret
```
(disassembly via `riscv64-unknown-elf-objdump -C -S --disassemble ./esp32c3-hal/target/riscv32imc-unknown-none-elf/release/examples/gpio_interrupt`)
This outcome is superior to hand-coded interrupt routines which, lacking visibility into any non-assembly body of the interrupt handler, have to be very conservative and save the [entire CPU state to the stack frame][full-frame-save]. By instead asking LLVM to only save the registers that it uses, we defer the decision to the tool with the best context: it can more accurately account for the cost of spills if it knows that every additional register used is already at the cost of an implicit spill.
At the LLVM level, this is apparently [implemented by] marking every register as "[callee-save]," matching the semantics of an interrupt handler nicely (it has to leave the CPU state just as it found it after its `{m|s}ret`).
This approach is not suitable for every interrupt handler, as it makes no attempt to e.g. save the state in a user-accessible stack frame. For a full discussion of those challenges and tradeoffs, please refer to [the interrupt calling conventions RFC][rfc].
Inside rustc, this implementation differs from prior art because LLVM does not expose the "all-saved" function flavor as a calling convention directly, instead preferring to use an attribute that allows for differentiating between "machine-mode" and "superivsor-mode" interrupts.
Finally, some effort has been made to guide those who may not yet be aware of the differences between machine-mode and supervisor-mode interrupts as to why no `riscv-interrupt` calling convention is exposed through rustc, and similarly for why `riscv-interrupt-u` makes no appearance (as it would complicate future LLVM upgrades).
[clang-attr]: https://clang.llvm.org/docs/AttributeReference.html#interrupt-risc-v
[full-frame-save]: 9281af2ecf/src/lib.rs (L440-L469)
[implemented by]: b7fb2a3fec/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp (L61-L67)
[callee-save]: 973f1fe7a8/llvm/lib/Target/RISCV/RISCVCallingConv.td (L30-L37)
[rfc]: https://github.com/rust-lang/rfcs/pull/3246
Similar to prior support added for the mips430, avr, and x86 targets
this change implements the rough equivalent of clang's
[`__attribute__((interrupt))`][clang-attr] for riscv targets, enabling
e.g.
```rust
static mut CNT: usize = 0;
pub extern "riscv-interrupt-m" fn isr_m() {
unsafe {
CNT += 1;
}
}
```
to produce highly effective assembly like:
```asm
pub extern "riscv-interrupt-m" fn isr_m() {
420003a0: 1141 addi sp,sp,-16
unsafe {
CNT += 1;
420003a2: c62a sw a0,12(sp)
420003a4: c42e sw a1,8(sp)
420003a6: 3fc80537 lui a0,0x3fc80
420003aa: 63c52583 lw a1,1596(a0) # 3fc8063c <_ZN12esp_riscv_rt3CNT17hcec3e3a214887d53E.0>
420003ae: 0585 addi a1,a1,1
420003b0: 62b52e23 sw a1,1596(a0)
}
}
420003b4: 4532 lw a0,12(sp)
420003b6: 45a2 lw a1,8(sp)
420003b8: 0141 addi sp,sp,16
420003ba: 30200073 mret
```
(disassembly via `riscv64-unknown-elf-objdump -C -S --disassemble ./esp32c3-hal/target/riscv32imc-unknown-none-elf/release/examples/gpio_interrupt`)
This outcome is superior to hand-coded interrupt routines which, lacking
visibility into any non-assembly body of the interrupt handler, have to
be very conservative and save the [entire CPU state to the stack
frame][full-frame-save]. By instead asking LLVM to only save the
registers that it uses, we defer the decision to the tool with the best
context: it can more accurately account for the cost of spills if it
knows that every additional register used is already at the cost of an
implicit spill.
At the LLVM level, this is apparently [implemented by] marking every
register as "[callee-save]," matching the semantics of an interrupt
handler nicely (it has to leave the CPU state just as it found it after
its `{m|s}ret`).
This approach is not suitable for every interrupt handler, as it makes
no attempt to e.g. save the state in a user-accessible stack frame. For
a full discussion of those challenges and tradeoffs, please refer to
[the interrupt calling conventions RFC][rfc].
Inside rustc, this implementation differs from prior art because LLVM
does not expose the "all-saved" function flavor as a calling convention
directly, instead preferring to use an attribute that allows for
differentiating between "machine-mode" and "superivsor-mode" interrupts.
Finally, some effort has been made to guide those who may not yet be
aware of the differences between machine-mode and supervisor-mode
interrupts as to why no `riscv-interrupt` calling convention is exposed
through rustc, and similarly for why `riscv-interrupt-u` makes no
appearance (as it would complicate future LLVM upgrades).
[clang-attr]: https://clang.llvm.org/docs/AttributeReference.html#interrupt-risc-v
[full-frame-save]: 9281af2ecf/src/lib.rs (L440-L469)
[implemented by]: b7fb2a3fec/llvm/lib/Target/RISCV/RISCVRegisterInfo.cpp (L61-L67)
[callee-save]: 973f1fe7a8/llvm/lib/Target/RISCV/RISCVCallingConv.td (L30-L37)
[rfc]: https://github.com/rust-lang/rfcs/pull/3246
Restrict linker version script of proc-macro crates to just its two symbols
Restrict linker version script of proc-macro crates to just the two symbols of each proc-macro crate.
The main known effect of doing this is to stop including `#[no_mangle]` symbols in the linker version script.
Background:
The combination of a proc-macro crate with an import of another crate that itself exports a no_mangle function was broken for a period of time, because:
* In PR #99944 we stopped exporting no_mangle symbols from proc-macro crates; proc-macro crates have a very limited interface and are meant to be treated as a blackbox to everything except rustc itself. However: he constructed linker version script still referred to them, but resolving that discrepancy was left as a FIXME in the code, tagged with issue #99978.
* In PR #108017 we started telling the linker to check (via the`--no-undefined-version` linker invocation flag) that every symbol referenced in the "linker version script" is provided as linker input. So the unresolved discrepancy from #99978 started surfacing as a compile-time error (e.g. #111888).
Fix#111888Fix#99978.
Add hotness data to LLVM remarks
Slight improvement of https://github.com/rust-lang/rust/pull/113040. This makes sure that if PGO is used, remarks generated using `-Zremark-dir` will include the `Hotness` attribute.
r? `@tmiasko`
[rustc_data_structures][base_n][perf] Remove unnecessary utf8 check.
Since all output characters taken from `BASE_64` are valid UTF8 chars there is no need to waste cycles on validation.
Even though it's obviously a perf win, I've also used a [benchmark](https://gist.github.com/ttsugriy/e1e63c07927d8f31e71695a9c617bbf3) on M1 MacBook Air with following results:
```
Running benches/base_n_benchmark.rs (target/release/deps/base_n_benchmark-825fe5895b5c2693)
push_str/old time: [14.670 µs 14.852 µs 15.074 µs]
Found 11 outliers among 100 measurements (11.00%)
4 (4.00%) high mild
7 (7.00%) high severe
push_str/new time: [12.573 µs 12.674 µs 12.801 µs]
Found 11 outliers among 100 measurements (11.00%)
7 (7.00%) high mild
4 (4.00%) high severe
```
rustc_interface: Dismantle `register_plugins` query
It did three independent things:
- Constructed `LintStore`
- Prepared incremental directories and dep graph
- Initialized some fields in `Session`
The `LintStore` construction (now `passes::create_lint_store`) is more or less left in place.
The incremental stuff is now moved into `fn dep_graph_future`.
This helps us to start loading the dep graph a bit earlier.
The `Session` field initialization is moved to tcx construction point.
Now that tcx is constructed early these fields don't even need to live in `Session`, they can live in tcx instead and be initialized at its creation (see the FIXME).
Three previously existing `rustc_interface` queries are de-querified (`register_plugins`, `dep_graph_future`, `dep_graph`) because they are only used locally in `fn global_ctxt` and their results don't need to be saved elsewhere.
On the other hand, `crate_types` and `stable_crate_id` are querified.
They are used from different places and their use is very similar to the existing `crate_name` query in this regard.
Rollup of 9 pull requests
Successful merges:
- #113568 (Fix spurious test failure with `panic=abort`)
- #114196 (Bubble up nested goals from equation in `predicates_for_object_candidate`)
- #114485 (Add trait decls to SMIR)
- #114495 (Set max_atomic_width for AVR to 16)
- #114496 (Set max_atomic_width for sparc-unknown-linux-gnu to 32)
- #114510 (llvm-wrapper: adapt for LLVM API changes)
- #114562 (stabilize abi_thiscall)
- #114570 ([miri][typo] Fix a typo in a vector_block comment.)
- #114573 (CI: do not hide error logs in a group)
r? `@ghost`
`@rustbot` modify labels: rollup
CI: do not hide error logs in a group
This PR avoids creating a GHA group at the very end of a CI workflow when some failure has happened. Before, when a failure has happened, its GHA group was not closed, however the clock drift check function would create a new group, which would actually close the group containing the error log, thus making errors hidden by default, which is not ideal.
See discussion here: https://rust-lang.zulipchat.com/#narrow/stream/326414-t-infra.2Fbootstrap/topic/GHA.20groups.20being.20closed.20on.20failures
r? bootstrap
Bubble up nested goals from equation in `predicates_for_object_candidate`
This used to be needed for https://github.com/rust-lang/rust/pull/114036#discussion_r1273987510, but since it's no longer, I'm opening this as a separate PR. This also fixes one ICEing UI test: (`tests/ui/unboxed-closures/issue-53448.rs`)
r? `@lcnr`
Make `unconditional_recursion` warning detect recursive drops
Closes#55388
Also closes#50049 unless we want to keep it for the second example which this PR does not solve, but I think it is better to track that work in #57965.
r? `@oli-obk` since you are the mentor for #55388
Unresolved questions:
- [x] There are two false positives that must be fixed before merging (see diff). I suspect the best way to solve them is to perform analysis after drop elaboration instead of before, as now, but I have not explored that any further yet. Could that be an option? **Answer:** Yes, that solved the problem.
`@rustbot` label +T-compiler +C-enhancement +A-lint
Don't provide `generate_default_from_new` when impl self ty is missing
Also don't provide the assist when the `Default` trait can't be found.
Part of #15398
internal: Turn unresolved proc macro expansions into missing expressions
Reduces the amount of type related errors one gets when proc macro expansion is disabled.
Optimize `Iterator` implementation for `&mut impl Iterator + Sized`
This adds a specialization trait to forward `fold`, `try_fold`,... to the inner iterator where possible
fix: Remove unwraps from "Generate delegate trait"
Fixes#15388
This is untested and purely mechanical, maybe some of those `unwrap`s actually made sense, but it probably doesn't hurt to avoid them.
Use the warning color when rust-analyzer is stopped
If the rust-analyzer server isn't running, we can't do much. Treat this state as a warning color, so it's more obvious.
SCIP: Qualify parameters by the containing function
SCIP requires symbols to be unique, but multiple functions may have a parameter with the same name. Qualify parameters according to the containing function.
SCIP requires symbols to be unique, but multiple functions may have a
parameter with the same name. Qualify parameters according to the
containing function.
Set the default status bar action to openLogs
Previously, clicking 'rust-analyzer' would stop the server entirely. This was easy to do accidentally, and then the user has to wait for the server to start up again.
Previously, clicking 'rust-analyzer' would stop the server
entirely. This was easy to do accidentally, and then the user has to
wait for the server to start up again.
Infer type in irrefutable slice patterns with fixed length as array
Fixes https://github.com/rust-lang/rust/issues/76342
In irrefutable slice patterns with a fixed length, we can infer the type as an array type. We now choose to prefer some implementations over others, e.g. in:
```
struct Zeroes;
const ARR: [usize; 2] = [0; 2];
const ARR2: [usize; 2] = [2; 2];
impl Into<&'static [usize; 2]> for Zeroes {
fn into(self) -> &'static [usize; 2] {
&ARR
}
}
impl Into<&'static [usize]> for Zeroes {
fn into(self) -> &'static [usize] {
&ARR2
}
}
fn main() {
let &[a, b] = Zeroes.into();
}
```
We now prefer the impl candidate `impl Into<&'static [usize; 2]> for Zeroes`, it's not entirely clear to me that this is correct, but given that the slice impl would require a type annotation anyway, this doesn't seem unreasonable.
r? `@lcnr`
Fix suggestion spans for expr from macro expansions
### Issue #112007: rustc shows expanded `writeln!` macro in code suggestion
#### Before This PR
```
help: consider using a semicolon here
|
6 | };
| +
help: you might have meant to return this value
--> C:\Users\hayle\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\lib/rustlib/src/rust\library\core\src\macros\mod.rs:557:9
|
55| return $dst.write_fmt($crate::format_args_nl!($($arg)*));
| ++++++ +
```
#### After This PR
```
help: consider using a semicolon here
|
LL | };
| +
help: you might have meant to return this value
|
LL | return writeln!(w, "but not here");
| ++++++ +
```
### Issue #110017: `format!` `.into()` suggestion deletes the `format` macro
#### Before This PR
```
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
--> /Users/eric/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/alloc/src/macros.rs:121:12
|
12| res.into()
| +++++++
```
#### After This PR
```
help: call `Into::into` on this expression to convert `String` into `Box<dyn std::error::Error>`
|
LL | Err(format!("error: {x}").into())
| +++++++
```
---
Fixes#112007.
Fixes#110017.
Clarify documentation for `CStr`
* Better differentiate summaries for `from_bytes_until_nul` and `from_bytes_with_nul`
* Add some links where they may be helpful
Suggest `x build library` for a custom toolchain that fails to load `core`
Fixes#113222
The nicer suggestion for dev-channel won't be emitted if `-Z ui-testing` enabled. IMO, this is acceptable for now.
Exclude non-identifier aliases from completion filtering text
When building `CompletionItem`s, this excludes aliases that aren't valid identifiers from the "lookup" text used to filter completions in the LSP client. Including them results in weird completion filtering behavior e.g. `Partial>` matching a completion for the `PartialOrd` trait because it has a doc alias of ">".
Closes#14692
