Local::borrow tweak and basic task pinning. #2

toddaaro · 2013-06-12T18:37:41Z

Includes two commits:

A modification of the Local::borrow function to support returning an argument. Required changing a large number of files to add an extra type parameter.
A basic implementation of task pinning. A task started with a designated "home" scheduler will only run on that scheduler. IO interactions are not yet implemented, and forwarding of tasks off "special" schedulers is not yet implemented.

Running with a high (greater than 100) RUST_RT_STRESS variable could result in nontrivial test execution times.

…ain io branch and modified the incoming new file lang.rs to be api-compatible

…ions have been planned for, and no forwarding of tasks off special schedulers is supported.

…e not pinned to them

…ueue

toddaaro · 2013-06-14T22:47:48Z

In response to the "run_anything" issue:

I'm not sure what exactly we want to do here. The current approach is entirely dependent on the shared work queue, and assumes that eventually a different scheduler will win on the dequeue. Without the shared dequeue we need some sort of forwarding location, and I'm not sure where that should be. Specifying on scheduler creation is a bit weird, but certainly possible. It creates a dependency cycle among the schedulers, where they need to know about each other for forwarding reasons.

In the short term initializing the platform thread by building it as the second scheduler, and having it point to the first scheduler, makes sense to me. But this assumes that we really don't want the enqueue locally in this case - I'm not sure what the real world hit is.

toddaaro · 2013-06-14T23:04:36Z

Paraphrasing some IRC discussion:

The servo usecase of a platform thread works well with brson's suggestion. We create a scheduler, then create the platform scheduler. The platform scheduler then gets the first scheduler's handle to use as a forwarding address.

The issue is the long term - in the currently not known usecase of lots of complicated scheduler pinning it becomes unpleasant to provide each scheduler an appropriate forwarding location, and to ensure that schedulers don't all forward to the same destination. This will require some thinking.

Since we know the scheduler design will change radically with the work stealing changes, we will do what works in the short term.

brson · 2013-06-16T00:35:13Z

Merged.

…inger Attempt #2 of [this pull request](rust-lang#8597) since my tired mind decided messing up my repo, then deleting and re-forking was a good idea. This is identical to the second last commit in that PR. (The one before I ruined everything.) This is an improvement to use_decl docs, which will hopefully improve understanding of how resolution works and where `extern mod` and module declarations should go to make them visible to use declarations.

…ariables Diagnostics such as the following ``` mismatched types: expected `core::result::Result<uint,()>`, found `core::option::Option<<generic #1>>` <anon>:6 let a: Result<uint, ()> = None; ^~~~ mismatched types: expected `&mut <generic #2>`, found `uint` <anon>:7 f(42u); ^~~ ``` tend to be fairly unappealing to new users. While specific type var IDs are valuable in diagnostics that deal with more than one such variable, in practice many messages only mention one. In those cases, leaving out the specific number makes the messages slightly less terrifying. In addition, type variables have been changed to use the type hole syntax `_` in diagnostics. With a variable ID, they're printed as `_#id` (e.g. `_#1`). In cases where the ID is left out, it's simply `_`. Integer and float variables have an additional suffix after the number, e.g. `_#1i` or `_#3f`.

…, r=nikomatsakis This PR aims to improve the readability of diagnostic messages that involve unresolved type variables. Currently, messages like the following: ```rust mismatched types: expected `core::result::Result<uint,()>`, found `core::option::Option<<generic #1>>` <anon>:6 let a: Result<uint, ()> = None; ^~~~ mismatched types: expected `&mut <generic #2>`, found `uint` <anon>:7 f(42u); ^~~ ``` tend to appear unapproachable to new users. [0] While specific type var IDs are valuable in diagnostics that deal with more than one such variable, in practice many messages only mention one. In those cases, leaving out the specific number makes the messages slightly less terrifying. ```rust mismatched types: expected `core::result::Result<uint, ()>`, found `core::option::Option<_>` <anon>:6 let a: Result<uint, ()> = None; ^~~~ mismatched types: expected `&mut _`, found `uint` <anon>:7 f(42u); ^~~ ``` As you can see, I also tweaked the aesthetics slightly by changing type variables to use the type hole syntax _. For integer variables, the syntax used is: ```rust mismatched types: expected `core::result::Result<uint, ()>`, found `core::option::Option<_#1i>` <anon>:6 let a: Result<uint, ()> = Some(1); ``` and float variables: ```rust mismatched types: expected `core::result::Result<uint, ()>`, found `core::option::Option<_#1f>` <anon>:6 let a: Result<uint, ()> = Some(0.5); ``` [0] https://twitter.com/coda/status/517713085465772032 Closes rust-lang#2632. Closes rust-lang#3404. Closes rust-lang#18426.

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.

Tiny typo of "positive"

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.

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) | ^^^ ```

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.

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 ```

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

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.

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, #24 [...] 6f54: e280b005 add fp, r0, #5 [...] 7018: e5cd001c strb r0, [sp, #28] 701c: e1a0082a lsr r0, sl, #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.

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, #24 [...] 6f54: e280b005 add fp, r0, #5 [...] 7018: e5cd001c strb r0, [sp, #28] 701c: e1a0082a lsr r0, sl, #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.

toddaaro added 4 commits June 10, 2013 15:29

debugged a compiler ICE when merging local::borrow changes into the m…

d64d26c

…ain io branch and modified the incoming new file lang.rs to be api-compatible

A basic implementation of pinning tasks to schedulers. No IO interact…

8428081

…ions have been planned for, and no forwarding of tasks off special schedulers is supported.

added functionality to tell schedulers to refuse to run tasks that ar…

4224fc7

…e not pinned to them

redesigned the pinning to pin deal with things on dequeue, not on enq…

d1ec8b5

…ueue

brson merged commit d1ec8b5 into brson:io Jun 16, 2013

brson pushed a commit that referenced this pull request Jul 30, 2015

Merge pull request #2 from ben0x539/patch-1

2d5c1bb

Tiny typo of "positive"

brson pushed a commit that referenced this pull request Mar 4, 2017

rposition() -> rev().position() (#2)

0982a28

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Local::borrow tweak and basic task pinning. #2

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Local::borrow tweak and basic task pinning. #2

Local::borrow tweak and basic task pinning. #2

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