Rollup of 7 pull requests#157464
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These methods return `io::Result` but did not document why they can fail or, importantly, that a child terminated by a signal is reported through its `ExitStatus` rather than as an `Err`. Add `# Errors` sections describing the common reasons spawning a child can fail (program not found, missing permission, resource exhaustion) and clarifying that a running child which exits unsuccessfully or is killed by a signal is not an error: those methods still return `Ok` and the outcome is reflected in the resulting `ExitStatus`.
…, r=lcnr Dont bail in error predicate unless self ty is error in new solver Continuation of rust-lang#146602. r? lcnr @lcnr rust-lang#146602 (comment) > I think we should move this out of assemble_builtin_impl_candidate to avoid ambiguity between e.g. blanket impls and the builtin impl candidate 🤔 Where do you want to put it?
… r=petrochenkov Staticlib hide internal symbols According to issue rust-lang#104707, when building a staticlib, all Rust internal symbols — mangled symbols, `#[rustc_std_internal_symbol]` items, allocator shims, etc. — leak out of the static archive. In contrast, cdylib correctly exports only `#[no_mangle]` symbols via a linker version script. `-Zstaticlib-hide-internal-symbols` directly post-processes ELF object files in the archive: parsing the `SHT_SYMTAB` sections and setting `STV_HIDDEN` visibility on any `GLOBAL/WEAK` defined symbol that is not in the exported symbol set, without changing the binding. This is an in-place modification (only writing the st_other byte per matching entry), with zero overhead. Supported on ELF targets (Linux, BSD, etc.) and Apple targets (macOS, iOS, etc.). On unsupported targets (Windows), a warning is emitted and the flag has no effect. **Update**: The rename counterpart (`-Zstaticlib-rename-internal-symbols`) is in rust-lang#156950. The test code are as follows: 1.a std rust staticlib: ```rust use std::collections::HashMap; use std::panic::{catch_unwind, AssertUnwindSafe}; #[no_mangle] pub extern "C" fn my_add(a: i32, b: i32) -> i32 { a + b } #[no_mangle] pub extern "C" fn my_hash_lookup(key: u64) -> u64 { let mut map = HashMap::new(); for i in 0..100u64 { map.insert(i, i.wrapping_mul(2654435761)); } *map.get(&key).unwrap_or(&0) } pub fn internal_reverse(s: &str) -> String { s.chars().rev().collect() } #[no_mangle] pub extern "C" fn my_format_number(n: i32) -> i32 { let s = format!("number: {}", n); s.len() as i32 } #[no_mangle] pub extern "C" fn my_safe_div(a: i32, b: i32) -> i32 { match catch_unwind(AssertUnwindSafe(|| { if b == 0 { panic!("division by zero!"); } a / b })) { Ok(result) => result, Err(_) => -1, } } #[no_mangle] pub extern "C" fn my_uncaught_panic() { panic!("uncaught panic across FFI"); } ``` 1.b downstream c program: ```c extern int my_add(int a, int b); extern unsigned long my_hash_lookup(unsigned long key); extern int my_format_number(int n); extern int my_safe_div(int a, int b); extern void my_uncaught_panic(void); int main() { int failures = 0; if (my_add(10, 20) != 30) failures++; if (my_hash_lookup(5) != 5UL * 2654435761UL) failures++; if (my_format_number(42) != 10) failures++; if (my_safe_div(100, 5) != 20) failures++; if (my_safe_div(100, 0) != -1) failures++; pid_t pid = fork(); if (pid == 0) { alarm(5); my_uncaught_panic(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 1.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin 616K 584K 33K (5%) 246 5 241 lto_fat 525K 525K 0 (0%) 6 5 1 opt_s 1.7M 1.5M 204K (12%) 1735 5 1730 opt_z 1.7M 1.5M 204K (12%) 1735 5 1730 lto_thin_z 602K 570K 32K (5%) 246 5 241 lto_fat_z 514K 514K 0 (0%) 6 5 1 full 514K 514K 0 (0%) 6 5 1 ``` 1.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin 616K 599K 18K (2%) 246 5 241 lto_fat 525K 535K -1% (-1%) 6 5 1 opt_s 1.7M 1.5M 162K (9%) 1735 5 1730 opt_z 1.7M 1.5M 162K (9%) 1735 5 1730 lto_thin_z 602K 585K 18K (2%) 246 5 241 lto_fat_z 514K 524K -1% (-1%) 6 5 1 full 514K 523K -1% (-1%) 6 5 1 ``` 2.a no_std rust staticlib ```rust #![no_std] #![feature(core_intrinsics)] use core::panic::PanicInfo; #[panic_handler] fn panic(_info: &PanicInfo) -> ! { loop {} } #[no_mangle] pub extern "C" fn embedded_add(a: i32, b: i32) -> i32 { a.wrapping_add(b) } #[no_mangle] pub extern "C" fn embedded_checksum(data: *const u8, len: usize) -> u8 { if data.is_null() { return 0; } let slice = unsafe { core::slice::from_raw_parts(data, len) }; let mut sum: u8 = 0; for &byte in slice { sum = sum.wrapping_add(byte); } sum } fn internal_helper() -> i32 { 42 } #[no_mangle] pub extern "C" fn call_internal() -> i32 { internal_helper() } #[no_mangle] pub extern "C" fn embedded_trigger_abort() { core::intrinsics::abort(); } ``` 2.b downstream c program ```c extern int embedded_add(int a, int b); extern unsigned char embedded_checksum(const unsigned char *data, unsigned long len); extern int call_internal(void); extern void embedded_trigger_abort(void); int main() { int failures = 0; if (embedded_add(10, 20) != 30) failures++; unsigned char data[] = {1, 2, 3}; if (embedded_checksum(data, 3) != 6) failures++; if (call_internal() != 42) failures++; pid_t pid = fork(); if (pid == 0) { embedded_trigger_abort(); _exit(0); } else { waitpid(pid, &status, 0); } return failures; } ``` The test results with different compiler flags(which might cause binary size reduction) are as follows: 2.c result with `-Zstaticlib-hide-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 429K 56K (11%) 490 4 486 lto_thin 180K 180K 0 (0%) 4 4 0 lto_fat 179K 179K 0 (0%) 4 4 0 opt_s 485K 429K 56K (11%) 490 4 486 opt_z 485K 429K 56K (11%) 490 4 486 lto_thin_z 180K 180K 0 (0%) 4 4 0 lto_fat_z 179K 179K 0 (0%) 4 4 0 full 179K 179K 0 (0%) 4 4 0 ``` 2.d result with `-Zstaticlib-hide-internal-symbols + -Zstaticlib-rename-internal-symbols` ``` settings OFF ON -Zsave ALL OFF.dynsym ON.dynsym ------------------------------------------------------------------------ default 485K 447K 39K (7%) 490 4 486 lto_thin 180K 189K -5% (-5%) 4 4 0 lto_fat 179K 189K -5% (-5%) 4 4 0 opt_s 485K 448K 38K (7%) 490 4 486 opt_z 485K 448K 38K (7%) 490 4 486 lto_thin_z 180K 189K -5% (-5%) 4 4 0 lto_fat_z 179K 189K -5% (-5%) 4 4 0 full 179K 189K -5% (-5%) 4 4 0 ``` Test results show that this compiler option is beneficial for scenarios where LTO cannot be enabled. r? @bjorn3 @petrochenkov
…rrow-suggestion, r=mejrs Suppress E0621 perpetual borrow suggestion Fixes rust-lang#156682 E0621 suggests `&'a mut Buffer<'a>` when you write `&mut Buffer<'a>` and the compiler wants a named lifetime on the outer reference. That ties both lifetimes together and makes the value unusable after the call. Usually it's not the info that the user actually needs. When the suggested fix would produce `&'a [mut] T` where `'a` also appears inside `T`, with the changes being implemented on this PR we now suppress the `help:` suggestion and instead emit a `help:` linking to the nomicon's borrow-splitting chapter, which explains the actual fix. Detection uses the pre-fold parameter type and only fires for mutable references, avoiding false positives on trait objects (`&dyn Foo` folds to `&'a (dyn Foo + 'a)`) and shared references (`&'a S<'a>` is often intentional). What we had before the changes: ``` help: add explicit lifetime `'a` to the type of `buffer` | 5 | pub fn foo<'a>(buffer: &'a mut Buffer<'a>) { | ++ ``` What we are going to have now after: ``` error[E0621]: explicit lifetime required in the type of `buffer` | 5 | buffer.buf = &mut buffer.buf[..]; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ lifetime `'a` required | = help: see <https://doc.rust-lang.org/nomicon/borrow-splitting.html> for more information about lifetime errors related to mutable references ```
…c, r=wesleywiser fix armv7a-none-eabihf tier doc I found that PR rust-lang#146522 promoted `armv7a-none-eabihf` from Tier 3 to Tier 2, updating the target spec, `armv7a-none-eabi.md` and `platform-support.md`, but missed updating `arm-none-eabi.md`. The target remained listed under Tier 3 in that file. So I move `armv7a-none-eabihf` from Tier 3 to Tier 2 in `arm-none-eabi.md`, merging it with the existing `armv7a-none-eabi` entry. This makes the documentation consistent with the actual tier in the target spec and `platform-support.md`. r? @wesleywiser
…-errors, r=LawnGnome
Document error conditions for `Command::{spawn, output, status}`
Fixes rust-lang#150361.
`Command::spawn`, `Command::output`, and `Command::status` all return `io::Result`, but the docs never explain *why* they can fail, and they do not mention the (easy to get wrong) distinction between a failure to spawn and a child that runs but exits unsuccessfully or is killed by a signal.
This adds an `# Errors` section to each method:
- **`spawn`** describes the common reasons spawning fails — the program not being found, lacking permission to execute it (e.g. not executable, or blocked by a policy such as `seccomp`), and the OS being unable to create the process due to resource exhaustion. It also clarifies that an error is only returned for failures *while spawning*; once the child has started, anything that happens to it (including signals) is reported through its `ExitStatus`.
- **`output`** and **`status`** refer back to `spawn` for the spawn failures, and explicitly note that a child which exits unsuccessfully or is terminated by a signal is **not** an error — they still return `Ok`, with the outcome reflected in the resulting `ExitStatus`.
The error conditions and the signal/`ExitStatus` behavior were confirmed by `@bjorn3` in the issue discussion.
Docs-only change; no code blocks were added or modified, and all intra-doc links (`io::Error`, `ExitStatus`, `Output`, `spawn`) follow link patterns already used in this module.
r? libs
…=mejrs Make distinction between crate-level attributes that are warned vs errored r? @mejrs This is a follow-up to rust-lang#157377 (comment) This PR makes all unstable crate-level attributes error on incorrect targets. To make the diff more helpful, I'd recommend reviewing the two commits separately. * The first commit introduces the infra & makes all crate-level attributes a warning, the commit should have no effect * The second commit undoes some changes from the first commit, to make all unstable crate-level attributes error
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Rollup of 7 pull requests Successful merges: - #150453 (Dont bail in error predicate unless self ty is error in new solver) - #155338 (Staticlib hide internal symbols) - #156892 (Suppress E0621 perpetual borrow suggestion) - #157135 (fix armv7a-none-eabihf tier doc) - #157360 (Document error conditions for `Command::{spawn, output, status}`) - #157418 (NVPTX: Add @kulst to the target maintainers) - #157443 (Make distinction between crate-level attributes that are warned vs errored)
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Rollup of 7 pull requests Successful merges: - #150453 (Dont bail in error predicate unless self ty is error in new solver) - #155338 (Staticlib hide internal symbols) - #156892 (Suppress E0621 perpetual borrow suggestion) - #157135 (fix armv7a-none-eabihf tier doc) - #157360 (Document error conditions for `Command::{spawn, output, status}`) - #157418 (NVPTX: Add @kulst to the target maintainers) - #157443 (Make distinction between crate-level attributes that are warned vs errored)
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Successful merges:
Command::{spawn, output, status}#157360 (Document error conditions forCommand::{spawn, output, status})r? @ghost
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