guide-ownership.md: fix typos #1
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Signed-off-by: Philipp Gesang <phg@phi-gamma.net>
|
Sorry, please submit this pull request against rust/rust rather than my fork! |
|
···<date: 2014-12-15, Monday>···<from: Steve Klabnik>···
Will do! |
steveklabnik
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Dec 30, 2014
Fixes rust-lang#19707. In terms of output, it currently uses the form `argument #1`, `argument #2`, etc. If anyone has any better suggestions I would be glad to consider them.
steveklabnik
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Nov 30, 2015
…hange Change verbiage in Stack & Heap page
steveklabnik
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Feb 26, 2016
suggest: Put the `use` in suggested code inside the quotes
Change import a trait suggestion from:
help: candidate #1: use `std::io::Write`
to
help: candidate #1: `use std::io::Write`
so that the code can be copied directly.
Fixes rust-lang#31864
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Aug 10, 2016
rustc_trans: don't Assert(Overflow(Neg)) when overflow checks are off. Generic functions using `Neg` on primitive types would panic even in release mode, with MIR trans. The solution is a bit hacky, as I'm checking the message, since there's no dedicated `CheckedUnOp`. Blocks Servo rustup ([failure #1](http://build.servo.org/builders/linux-rel/builds/2477/steps/test_3/logs/stdio), [failure #2](http://build.servo.org/builders/mac-rel-css/builds/2364/steps/test/logs/stdio)) - this should be the last hurdle, it affects only one test.
steveklabnik
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Jan 23, 2017
For a given file
```rust
trait A { fn foo(&self) {} }
trait B : A { fn foo(&self) {} }
fn bar<T: B>(a: &T) {
a.foo()
}
```
provide the following output
```
error[E0034]: multiple applicable items in scope
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^ multiple `foo` found
|
note: candidate #1 is defined in the trait `A`
--> file.rs:2:11
|
2 | trait A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `A::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
note: candidate #2 is defined in the trait `B`
--> file.rs:3:15
|
3 | trait B : A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `B::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
```
steveklabnik
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Jan 23, 2017
E0034: provide disambiguated syntax for candidates
For a given file
```rust
trait A { fn foo(&self) {} }
trait B : A { fn foo(&self) {} }
fn bar<T: B>(a: &T) {
a.foo()
}
```
provide the following output
```
error[E0034]: multiple applicable items in scope
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^ multiple `foo` found
|
note: candidate #1 is defined in the trait `A`
--> file.rs:2:11
|
2 | trait A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `A::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
note: candidate #2 is defined in the trait `B`
--> file.rs:3:15
|
3 | trait B : A { fn foo(&self, a: usize) {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to use it here write `B::foo(&a, 1)` instead
--> file.rs:6:5
|
6 | a.foo(1)
| ^^^
```
Fix rust-lang#37767.
steveklabnik
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Feb 9, 2017
LeakSanitizer, ThreadSanitizer, AddressSanitizer and MemorySanitizer support
```
$ cargo new --bin leak && cd $_
$ edit Cargo.toml && tail -n3 $_
```
``` toml
[profile.dev]
opt-level = 1
```
```
$ edit src/main.rs && cat $_
```
``` rust
use std::mem;
fn main() {
let xs = vec![0, 1, 2, 3];
mem::forget(xs);
}
```
```
$ RUSTFLAGS="-Z sanitizer=leak" cargo run --target x86_64-unknown-linux-gnu; echo $?
Finished dev [optimized + debuginfo] target(s) in 0.0 secs
Running `target/debug/leak`
=================================================================
==10848==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 16 byte(s) in 1 object(s) allocated from:
#0 0x557c3488db1f in __interceptor_malloc /shared/rust/checkouts/lsan/src/compiler-rt/lib/lsan/lsan_interceptors.cc:55
#1 0x557c34888aaa in alloc::heap::exchange_malloc::h68f3f8b376a0da42 /shared/rust/checkouts/lsan/src/liballoc/heap.rs:138
#2 0x557c34888afc in leak::main::hc56ab767de6d653a $PWD/src/main.rs:4
#3 0x557c348c0806 in __rust_maybe_catch_panic ($PWD/target/debug/leak+0x3d806)
SUMMARY: LeakSanitizer: 16 byte(s) leaked in 1 allocation(s).
23
```
```
$ cargo new --bin racy && cd $_
$ edit src/main.rs && cat $_
```
``` rust
use std::thread;
static mut ANSWER: i32 = 0;
fn main() {
let t1 = thread::spawn(|| unsafe { ANSWER = 42 });
unsafe {
ANSWER = 24;
}
t1.join().ok();
}
```
```
$ RUSTFLAGS="-Z sanitizer=thread" cargo run --target x86_64-unknown-linux-gnu; echo $?
==================
WARNING: ThreadSanitizer: data race (pid=12019)
Write of size 4 at 0x562105989bb4 by thread T1:
#0 racy::main::_$u7b$$u7b$closure$u7d$$u7d$::hbe13ea9e8ac73f7e $PWD/src/main.rs:6 (racy+0x000000010e3f)
#1 _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h2e466a92accacc78 /shared/rust/checkouts/lsan/src/libstd/panic.rs:296 (racy+0x000000010cc5)
#2 std::panicking::try::do_call::h7f4d2b38069e4042 /shared/rust/checkouts/lsan/src/libstd/panicking.rs:460 (racy+0x00000000c8f2)
#3 __rust_maybe_catch_panic <null> (racy+0x0000000b4e56)
#4 std::panic::catch_unwind::h31ca45621ad66d5a /shared/rust/checkouts/lsan/src/libstd/panic.rs:361 (racy+0x00000000b517)
#5 std::thread::Builder::spawn::_$u7b$$u7b$closure$u7d$$u7d$::hccfc37175dea0b01 /shared/rust/checkouts/lsan/src/libstd/thread/mod.rs:357 (racy+0x00000000c226)
#6 _$LT$F$u20$as$u20$alloc..boxed..FnBox$LT$A$GT$$GT$::call_box::hd880bbf91561e033 /shared/rust/checkouts/lsan/src/liballoc/boxed.rs:605 (racy+0x00000000f27e)
#7 std::sys::imp::thread::Thread::new::thread_start::hebdfc4b3d17afc85 <null> (racy+0x0000000abd40)
Previous write of size 4 at 0x562105989bb4 by main thread:
#0 racy::main::h23e6e5ca46d085c3 $PWD/src/main.rs:8 (racy+0x000000010d7c)
#1 __rust_maybe_catch_panic <null> (racy+0x0000000b4e56)
#2 __libc_start_main <null> (libc.so.6+0x000000020290)
Location is global 'racy::ANSWER::h543d2b139f819b19' of size 4 at 0x562105989bb4 (racy+0x0000002f8bb4)
Thread T1 (tid=12028, running) created by main thread at:
#0 pthread_create /shared/rust/checkouts/lsan/src/compiler-rt/lib/tsan/rtl/tsan_interceptors.cc:902 (racy+0x00000001aedb)
#1 std::sys::imp::thread::Thread::new::hce44187bf4a36222 <null> (racy+0x0000000ab9ae)
#2 std::thread::spawn::he382608373eb667e /shared/rust/checkouts/lsan/src/libstd/thread/mod.rs:412 (racy+0x00000000b5aa)
#3 racy::main::h23e6e5ca46d085c3 $PWD/src/main.rs:6 (racy+0x000000010d5c)
#4 __rust_maybe_catch_panic <null> (racy+0x0000000b4e56)
#5 __libc_start_main <null> (libc.so.6+0x000000020290)
SUMMARY: ThreadSanitizer: data race $PWD/src/main.rs:6 in racy::main::_$u7b$$u7b$closure$u7d$$u7d$::hbe13ea9e8ac73f7e
==================
ThreadSanitizer: reported 1 warnings
66
```
```
$ cargo new --bin oob && cd $_
$ edit src/main.rs && cat $_
```
``` rust
fn main() {
let xs = [0, 1, 2, 3];
let y = unsafe { *xs.as_ptr().offset(4) };
}
```
```
$ RUSTFLAGS="-Z sanitizer=address" cargo run --target x86_64-unknown-linux-gnu; echo $?
=================================================================
==13328==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fff29f3ecd0 at pc 0x55802dc6bf7e bp 0x7fff29f3ec90 sp 0x7fff29f3ec88
READ of size 4 at 0x7fff29f3ecd0 thread T0
#0 0x55802dc6bf7d in oob::main::h0adc7b67e5feb2e7 $PWD/src/main.rs:3
#1 0x55802dd60426 in __rust_maybe_catch_panic ($PWD/target/debug/oob+0xfe426)
#2 0x55802dd58dd9 in std::rt::lang_start::hb2951fc8a59d62a7 ($PWD/target/debug/oob+0xf6dd9)
#3 0x55802dc6c002 in main ($PWD/target/debug/oob+0xa002)
#4 0x7fad8c3b3290 in __libc_start_main (/usr/lib/libc.so.6+0x20290)
#5 0x55802dc6b719 in _start ($PWD/target/debug/oob+0x9719)
Address 0x7fff29f3ecd0 is located in stack of thread T0 at offset 48 in frame
#0 0x55802dc6bd5f in oob::main::h0adc7b67e5feb2e7 $PWD/src/main.rs:1
This frame has 1 object(s):
[32, 48) 'xs' <== Memory access at offset 48 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
(longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow $PWD/src/main.rs:3 in oob::main::h0adc7b67e5feb2e7
Shadow bytes around the buggy address:
0x1000653dfd40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfd50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfd60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfd70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x1000653dfd90: 00 00 00 00 f1 f1 f1 f1 00 00[f3]f3 00 00 00 00
0x1000653dfda0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfdb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfdc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfdd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x1000653dfde0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Heap right redzone: fb
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack partial redzone: f4
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
==13328==ABORTING
1
```
```
$ cargo new --bin uninit && cd $_
$ edit src/main.rs && cat $_
```
``` rust
use std::mem;
fn main() {
let xs: [u8; 4] = unsafe { mem::uninitialized() };
let y = xs[0] + xs[1];
}
```
```
$ RUSTFLAGS="-Z sanitizer=memory" cargo run; echo $?
==30198==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x563f4b6867da in uninit::main::hc2731cd4f2ed48f8 $PWD/src/main.rs:5
#1 0x563f4b7033b6 in __rust_maybe_catch_panic ($PWD/target/debug/uninit+0x873b6)
#2 0x563f4b6fbd69 in std::rt::lang_start::hb2951fc8a59d62a7 ($PWD/target/debug/uninit+0x7fd69)
#3 0x563f4b6868a9 in main ($PWD/target/debug/uninit+0xa8a9)
#4 0x7fe844354290 in __libc_start_main (/usr/lib/libc.so.6+0x20290)
#5 0x563f4b6864f9 in _start ($PWD/target/debug/uninit+0xa4f9)
SUMMARY: MemorySanitizer: use-of-uninitialized-value $PWD/src/main.rs:5 in uninit::main::hc2731cd4f2ed48f8
Exiting
77
```
steveklabnik
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Feb 28, 2017
steveklabnik
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Mar 8, 2017
Group "missing variable bind" spans in `or` matches and clarify wording for the two possible cases: when a variable from the first pattern is not in any of the subsequent patterns, and when a variable in any of the other patterns is not in the first one. Before: ``` error[E0408]: variable `a` from pattern #1 is not bound in pattern #2 --> file.rs:10:23 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^^^^ pattern doesn't bind `a` error[E0408]: variable `b` from pattern #2 is not bound in pattern #1 --> file.rs:10:32 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^ pattern doesn't bind `b` error[E0408]: variable `a` from pattern #1 is not bound in pattern #3 --> file.rs:10:37 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^ pattern doesn't bind `a` error[E0408]: variable `d` from pattern #1 is not bound in pattern #3 --> file.rs:10:37 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^ pattern doesn't bind `d` error[E0408]: variable `c` from pattern #3 is not bound in pattern #1 --> file.rs:10:43 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^ pattern doesn't bind `c` error[E0408]: variable `d` from pattern #1 is not bound in pattern #4 --> file.rs:10:48 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^ pattern doesn't bind `d` error: aborting due to 6 previous errors ``` After: ``` error[E0408]: variable `a` is not bound in all patterns --> file.rs:20:37 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { intln!("{:?}", a); } | - ^^^^^^^^^^^ ^^^^^^^^ - variable t in all patterns | | | | | | | pattern doesn't bind `a` | | pattern doesn't bind `a` | variable not in all patterns error[E0408]: variable `d` is not bound in all patterns --> file.rs:20:37 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { intln!("{:?}", a); } | - - ^^^^^^^^ ^^^^^^^^ pattern esn't bind `d` | | | | | | | pattern doesn't bind `d` | | variable not in all patterns | variable not in all patterns error[E0408]: variable `b` is not bound in all patterns --> file.rs:20:37 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { intln!("{:?}", a); } | ^^^^^^^^^^^ - ^^^^^^^^ ^^^^^^^^ pattern esn't bind `b` | | | | | | | pattern doesn't bind `b` | | variable not in all patterns | pattern doesn't bind `b` error[E0408]: variable `c` is not bound in all patterns --> file.rs:20:48 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { intln!("{:?}", a); } | ^^^^^^^^^^^ ^^^^^^^^^^^ - ^^^^^^^^ pattern esn't bind `c` | | | | | | | variable not in all tterns | | pattern doesn't bind `c` | pattern doesn't bind `c` error: aborting due to 4 previous errors ``` * Have only one presentation for binding consistency errors * Point to same binding in multiple patterns when possible * Check inconsistent bindings in all arms * Simplify wording of diagnostic message * Sort emition and spans of binding errors for deterministic output
steveklabnik
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Mar 8, 2017
Clean up "pattern doesn't bind x" messages Group "missing variable bind" spans in `or` matches and clarify wording for the two possible cases: when a variable from the first pattern is not in any of the subsequent patterns, and when a variable in any of the other patterns is not in the first one. Before: ```rust error[E0408]: variable `a` from pattern #1 is not bound in pattern #2 --> file.rs:10:23 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^^^^ pattern doesn't bind `a` error[E0408]: variable `b` from pattern #2 is not bound in pattern #1 --> file.rs:10:32 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^ pattern doesn't bind `b` error[E0408]: variable `a` from pattern #1 is not bound in pattern #3 --> file.rs:10:37 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^ pattern doesn't bind `a` error[E0408]: variable `d` from pattern #1 is not bound in pattern #3 --> file.rs:10:37 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^ pattern doesn't bind `d` error[E0408]: variable `c` from pattern #3 is not bound in pattern #1 --> file.rs:10:43 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^ pattern doesn't bind `c` error[E0408]: variable `d` from pattern #1 is not bound in pattern #4 --> file.rs:10:48 | 10 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^ pattern doesn't bind `d` error: aborting due to 6 previous errors ``` After: ```rust error[E0408]: variable `d` is not bound in all patterns --> $DIR/issue-39698.rs:20:37 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | - - ^^^^^^^^ ^^^^^^^^ pattern doesn't bind `d` | | | | | | | pattern doesn't bind `d` | | variable not in all patterns | variable not in all patterns error[E0408]: variable `c` is not bound in all patterns --> $DIR/issue-39698.rs:20:48 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^^^^ ^^^^^^^^^^^ - ^^^^^^^^ pattern doesn't bind `c` | | | | | | | variable not in all patterns | | pattern doesn't bind `c` | pattern doesn't bind `c` error[E0408]: variable `a` is not bound in all patterns --> $DIR/issue-39698.rs:20:37 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | - ^^^^^^^^^^^ ^^^^^^^^ - variable not in all patterns | | | | | | | pattern doesn't bind `a` | | pattern doesn't bind `a` | variable not in all patterns error[E0408]: variable `b` is not bound in all patterns --> $DIR/issue-39698.rs:20:37 | 20 | T::T1(a, d) | T::T2(d, b) | T::T3(c) | T::T4(a) => { println!("{:?}", a); } | ^^^^^^^^^^^ - ^^^^^^^^ ^^^^^^^^ pattern doesn't bind `b` | | | | | | | pattern doesn't bind `b` | | variable not in all patterns | pattern doesn't bind `b` error: aborting due to 4 previous errors ``` Fixes rust-lang#39698.
steveklabnik
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Without that flag, LLVM generates unaligned memory access instructions, which are not allowed on ARMv5.
For example, the 'hello world' example from `cargo --new` failed with:
```
$ ./hello
Hello, world!
thread 'main' panicked at 'assertion failed: end <= len', src/libcollections/vec.rs:1113
note: Run with `RUST_BACKTRACE=1` for a backtrace.
```
I traced this error back to the following assembler code in `BufWriter::flush_buf`:
```
6f44: e28d0018 add r0, sp, rust-lang#24
[...]
6f54: e280b005 add fp, r0, #5
[...]
7018: e5cd001c strb r0, [sp, rust-lang#28]
701c: e1a0082a lsr r0, sl, rust-lang#16
7020: 03a01001 moveq r1, #1
7024: e5cb0002 strb r0, [fp, #2]
7028: e1cba0b0 strh sl, [fp]
```
Note that `fp` points to `sp + 29`, so the three `str*`-instructions should fill up a 32bit - value at `sp + 28`, which is later used as the value `n` in `Ok(n) => written += n`. This doesn't work on ARMv5 as the `strh` can't write to the unaligned contents of `fp`, so the upper bits of `n` won't get cleared, leading to the assertion failure in Vec::drain.
With `+strict-align`, the code works as expected.
steveklabnik
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Jun 5, 2017
ARMv5 needs +strict-align
Without that flag, LLVM generates unaligned memory access instructions, which are not allowed on ARMv5.
For example, the 'hello world' example from `cargo --new` failed with:
```
$ ./hello
Hello, world!
thread 'main' panicked at 'assertion failed: end <= len', src/libcollections/vec.rs:1113
note: Run with `RUST_BACKTRACE=1` for a backtrace.
```
I traced this error back to the following assembler code in `BufWriter::flush_buf`:
```
6f44: e28d0018 add r0, sp, rust-lang#24
[...]
6f54: e280b005 add fp, r0, #5
[...]
7018: e5cd001c strb r0, [sp, rust-lang#28]
701c: e1a0082a lsr r0, sl, rust-lang#16
7020: 03a01001 moveq r1, #1
7024: e5cb0002 strb r0, [fp, #2]
7028: e1cba0b0 strh sl, [fp]
```
Note that `fp` points to `sp + 29`, so the three `str*`-instructions should fill up a 32bit - value at `sp + 28`, which is later used as the value `n` in `Ok(n) => written += n`. This doesn't work on ARMv5 as the `strh` can't write to the unaligned contents of `fp`, so the upper bits of `n` won't get cleared, leading to the assertion failure in Vec::drain.
With `+strict-align`, the code works as expected.
steveklabnik
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Oct 11, 2017
…crichton Allow atomic operations up to 32 bits The ARMv5te platform does not have instruction-level support for atomics, however the kernel provides [user space helpers] which can be used to perform atomic operations. When linked with `libgcc`, the atomic symbols needed by Rust will be provided, rather than CPU level intrinsics. [user space helpers]: https://www.kernel.org/doc/Documentation/arm/kernel_user_helpers.txt 32-bit versions of these kernel level helpers were introduced in Linux Kernel 2.6.12, and 64-bit version of these kernel level helpers were introduced in Linux Kernel 3.1. I have selected 32 bit versions as std currently only requires Linux version 2.6.18 and above as far as I am aware. As this target is specifically linux and gnueabi, it is reasonable to assume the Linux Kernel and libc will be available for the target. There is a large performance penalty, as we are not using CPU level intrinsics, however this penalty is likely preferable to not having the target at all. I have used this change in a custom target (along with xargo) to build std, as well as a number of higher level crates. ## Additional information For reference, here is what a a code snippet decompiles to: ```rust use std::sync::atomic::{AtomicIsize, Ordering}; #[no_mangle] pub extern fn foo(a: &AtomicIsize) -> isize { a.fetch_add(1, Ordering::SeqCst) } ``` ``` Disassembly of section .text.foo: 00000000 <foo>: 0: e92d4800 push {fp, lr} 4: e3a01001 mov r1, #1 8: ebfffffe bl 0 <__sync_fetch_and_add_4> c: e8bd8800 pop {fp, pc} ``` Which in turn is provided by `libgcc.a`, which has code which looks like this: ``` Disassembly of section .text: 00000000 <__sync_fetch_and_add_4>: 0: e92d40f8 push {r3, r4, r5, r6, r7, lr} 4: e1a05000 mov r5, r0 8: e1a07001 mov r7, r1 c: e59f6028 ldr r6, [pc, rust-lang#40] ; 3c <__sync_fetch_and_add_4+0x3c> 10: e5954000 ldr r4, [r5] 14: e1a02005 mov r2, r5 18: e1a00004 mov r0, r4 1c: e0841007 add r1, r4, r7 20: e1a0e00f mov lr, pc 24: e12fff16 bx r6 28: e3500000 cmp r0, #0 2c: 1afffff7 bne 10 <__sync_fetch_and_add_4+0x10> 30: e1a00004 mov r0, r4 34: e8bd40f8 pop {r3, r4, r5, r6, r7, lr} 38: e12fff1e bx lr 3c: ffff0fc0 .word 0xffff0fc0 ``` Where you can see the reference to `0xffff0fc0`, which is provided by the [user space helpers].
steveklabnik
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Dec 30, 2017
…r=michaelwoerister Set the dwarf linkage_name to the mangled name ref rust-lang#46453 @michaelwoerister or anyone else who knows, i'm not sure if this is the correct instance to pass here (or how to get the correct one precisely): https://github.com//m4b/rust/blob/5a94a48678ec0a20ea6a63a783e63546bf9459b1/src/librustc_trans/debuginfo/namespace.rs#L36 So don't merge this yet, I'd like to learn about correct instance first; however, I think this already fixes a bunch of weirdness i'm seeing debugging from time to time, not to mention backtraces in gdb via `bt` are now ~readable~ meaningful 🎉 E.g.: new: ``` (gdb) bt #0 <inline::Foo as core::convert::From<()>>::from () at /home/m4b/tmp/bad_debug/inline.rs:11 #1 0x000055555555a35d in inline::deadbeef () at /home/m4b/tmp/bad_debug/inline.rs:16 #2 0x000055555555a380 in inline::main () at /home/m4b/tmp/bad_debug/inline.rs:20 ``` old: ``` (gdb) bt #0 inline::{{impl}}::from () at /home/m4b/tmp/bad_debug/inline.rs:11 #1 0x000055555555b0ed in inline::deadbeef () at /home/m4b/tmp/bad_debug/inline.rs:16 #2 0x000055555555b120 in inline::main () at /home/m4b/tmp/bad_debug/inline.rs:20 ```
steveklabnik
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May 3, 2018
Building for x86_64-unknown-linux-musl currently results in an executable lacking debug information for musl libc itself. If you request a backtrace in GDB while control flow is within musl – including sycalls made by musl – the result looks like: #0 0x0000000000434b46 in __cp_end () #1 0x0000000000432dbd in __syscall_cp_c () #2 0x0000000000000000 in ?? () i.e. not very helpful. Adding --enable-debug resolves this, and --enable-optimize re-enables optimisations which default to off given the previous flag.
steveklabnik
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May 3, 2018
Add --enable-debug flag to musl CI build script Building for x86_64-unknown-linux-musl currently results in an executable lacking debug information for musl libc itself. If you request a backtrace in GDB while control flow is within musl – including sycalls made by musl – the result looks like: ``` #0 0x0000000000434b46 in __cp_end () #1 0x0000000000432dbd in __syscall_cp_c () #2 0x0000000000000000 in ?? () ``` i.e. not very helpful. Adding --enable-debug resolves this, and --enable-optimize re-enables optimisations which default to off given the previous flag.
steveklabnik
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May 21, 2018
There is a hot path through `opt_normalize_projection_type`: - `try_start` does a cache lookup (#1). - The result is a `NormalizedTy`. - There are no unresolved type vars, so we call `complete`. - `complete` does *another* cache lookup (#2), then calls `SnapshotMap::insert`. - `insert` does *another* cache lookup (#3), inserting the same value that's already in the cache. This patch optimizes this hot path by introducing `complete_normalized`, for use when the value is known in advance to be a `NormalizedTy`. It always avoids lookup #2. Furthermore, if the `NormalizedTy`'s obligations are empty (the common case), we know that lookup #3 would be a no-op, so we avoid it, while inserting a Noop into the `SnapshotMap`'s undo log.
steveklabnik
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Jun 5, 2018
When encountering an unexisting method for a given trait where an associated function has the same name, suggest using the appropriate syntax, instead of using `help` text. When only one candidate is found, do not call it "candidate #1", just call it "the candidate".
steveklabnik
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Jun 5, 2018
Tweak output on E0599 for assoc fn used as method - Use suggestion instead of `help` when possible - Add primary span label - Remove incorrect `help` suggestion using incorrect syntax - Do not refer to only one possible candidate as `candidate #1`, refer to it as `the candidate`
steveklabnik
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Jul 5, 2018
Suggestion for 'static impl Trait return When encountering a named or anonymous sup requirement (for example, `&'a self`) and a `'static` impl Trait return type, suggest adding the `'_` lifetime constraing to the return type. Fix rust-lang#43719, rust-lang#51282. ``` error: cannot infer an appropriate lifetime --> $DIR/static-return-lifetime-infered.rs:17:16 | LL | fn iter_values_anon(&self) -> impl Iterator<Item=u32> { | ----------------------- this return type evaluates to the `'static` lifetime... LL | self.x.iter().map(|a| a.0) | ------ ^^^^ | | | ...but this borrow... | note: ...can't outlive the anonymous lifetime #1 defined on the method body at 16:5 --> $DIR/static-return-lifetime-infered.rs:16:5 | LL | / fn iter_values_anon(&self) -> impl Iterator<Item=u32> { LL | | self.x.iter().map(|a| a.0) LL | | } | |_____^ help: you can add a constraint to the return type to make it last less than `'static` and match the anonymous lifetime #1 defined on the method body at 16:5 | LL | fn iter_values_anon(&self) -> impl Iterator<Item=u32> + '_ { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ```
steveklabnik
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Oct 29, 2018
sync fork with upstream (master)
steveklabnik
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Jan 17, 2019
Explain safety for `vec.set_len(0)`
steveklabnik
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Jun 16, 2020
…ing opaque return type
Go from
```
error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
--> file8.rs:22:5
|
22 | / move || {
23 | | *dest = g.get();
24 | | }
| |_____^
|
note: first, the lifetime cannot outlive the anonymous lifetime #1 defined on the function body at 18:1...
--> file8.rs:18:1
|
18 | / fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
19 | | where
20 | | G: Get<T>
21 | | {
... |
24 | | }
25 | | }
| |_^
note: ...so that the types are compatible
--> file8.rs:22:5
|
22 | / move || { //~ ERROR cannot infer an appropriate lifetime
23 | | *dest = g.get();
24 | | }
| |_____^
= note: expected `&mut T`
found `&mut T`
note: but, the lifetime must be valid for the lifetime `'a` as defined on the function body at 18:8...
--> file8.rs:18:8
|
18 | fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
| ^^
note: ...so that return value is valid for the call
--> file8.rs:18:45
|
18 | fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
| ^^^^^^^^^^^^^^^^^^^^^^^
```
to
```
error[E0621]: explicit lifetime required in the type of `dest`
--> file8.rs:18:45
|
18 | fn bat<'a, G: 'a, T>(g: G, dest: &mut T) -> impl FnOnce() + '_ + 'a
| ------ ^^^^^^^^^^^^^^^^^^^^^^^ lifetime `'a` required
| |
| help: add explicit lifetime `'a` to the type of `dest`: `&'a mut T`
```
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Signed-off-by: Philipp Gesang phg@phi-gamma.net