The current implementation/documentation was made to avoid sNaN because of
potential safety issues implied by old/bad LLVM documentation. These issues
aren't real, so we can just make the implementation transmute (as permitted
by the existing documentation of this method).
Also the documentation didn't actually match the behaviour: it said we may
change sNaNs, but in fact we canonicalized *all* NaNs.
Also an example in the documentation was wrong: it said we *always* change
sNaNs, when the documentation was explicitly written to indicate it was
implementation-defined.
This makes to_bits and from_bits perfectly roundtrip cross-platform, except
for one caveat: although the 2008 edition of IEEE-754 specifies how to
interpet the signaling bit, earlier editions didn't. This lead to some platforms
picking the opposite interpretation, so all signaling NaNs on x86/ARM are quiet
on MIPS, and vice-versa.
NaN-boxing is a fairly important optimization, while we don't even guarantee
that float operations properly preserve signalingness. As such, this seems like
the more natural strategy to take (as opposed to trying to mangle the signaling
bit on a per-platform basis).
This implementation is also, of course, faster.
rustc_driver: expose a way to override query providers in CompileController.
This API has been a long-time coming and will probably become the main method for custom drivers (that is, binaries other than `rustc` itself that use `librustc_driver`) to adapt the compiler's behavior.
always add an unreachable branch on matches to give more info to llvm
As part of https://github.com/djzin/rustc-optimization I discovered that some simple enum optimizations (src/unary/three_valued_enum.rs and src/unary/four_valued_enum.rs in the repo) are not applied - and the reason for this is that we erase the info that the discriminant of an enum is one of the options by putting the last one in an "otherwise" branch. This patch adds an extra branch so that LLVM can know what the possibilities are for the discriminant, which fixes the three- and four- valued cases.
Note that for whatever reason, this doesn't fix the case of 2 variants (most notably `Option` and `Result` have 2 variants) - a pass re-ordering might fix this or we may wish to add "assume" annotations on discriminants to force it to optimize.
MIR-borrowck: don't ICE for cannot move from array error
Closes#45694
compile-fail test E0508 now gives
```text
error[E0508]: cannot move out of type `[NonCopy; 1]`, a non-copy array (Ast)
--> .\src\test\compile-fail\E0508.rs:18:18
|
18 | let _value = array[0]; //[ast]~ ERROR E0508
| ^^^^^^^^
| |
| cannot move out of here
| help: consider using a reference instead: `&array[0]`
error[E0508]: cannot move out of type `[NonCopy; 1]`, a non-copy array (Mir)
--> .\src\test\compile-fail\E0508.rs:18:18
|
18 | let _value = array[0]; //[ast]~ ERROR E0508
| ^^^^^^^^ cannot move out of here
error: aborting due to 2 previous errors
```
Use #!/usr/bin/env as shebang for Bash scripts
On some systems, the bash command could be available in another
directory than /bin. As such, to offer an env shebang is more
convenient.
This make sense even for docker scripts, as you can use Docker
on FreeBSD or SmartOS for example.
update match-expressions.rs with DepNode labels
As a part of #44924, I have updated the match-expressions.rs. The PR has tests verified for the following dependency nodes for let-expressions
- MirValidated
- MirOptimized
- TypeCheckTables
- TypeOfItem
- GenericsOfItem
- PredicatesOfItem
- FnSignature
cc @michaelwoerister
r? @nikomatsakis
Use getrandom syscall for all Linux and Android targets.
I suppose we can use it in all Linux and Android targets. In function `is_getrandom_available` is checked if the syscall is available (getrandom syscall was add in version 3.17 of Linux kernel), if the syscall is not available `fill_bytes` fallback to reading from `/dev/urandom`.
Update libc to include getrandom related constants.
rustc_mir: hardcode pass list internally and remove premature pluggability.
Fixes#41712 by moving the MIR pass lists from `rustc_driver` to `rustc_mir`.
The application of the passes is done with the `rustc_mir::transform::run_passes` macro, which is public, as are all the passes AFAIK, and can be used to apply MIR passes outside of `rustc_mir`.
With the ability to override query providers through the `rustc_driver` (orthogonal to, and not included in this PR), custom drivers will be able to substitute the entire pass list if they want to.
**EDIT**: the aforementioned ability is added by #45944.
r? @nikomatsakis
incr.comp.: Don't crash in DepGraph::try_mark_green() when encountering a removed input node.
Fixes a small regression that was introduced in #45867.
r? @nikomatsakis
check::method - unify receivers before normalizing method signatures
Normalizing method signatures can unify inference variables, which can
cause receiver unification to fail. Unify the receivers first to avoid
that.
Fixes#36701.
Fixes#45801.
Fixes#45855.
r? @eddyb
beta-nominating because #43880 made this ICE happen in more cases (the code in that issue ICEs post-#43880 only, but the unit test here ICEs on all versions).
On some systems, the bash command could be available in another
directory than /bin. As such, to offer an env shebang is more
convenient.
This make sense even for docker scripts, as you can use Docker
on FreeBSD or SmartOS for example.
