Not only can discriminants be smaller than int now, but they can be
larger than int on 32-bit targets. This has obvious implications for the
reflection interface. Without this change, things fail with LLVM
assertions when we try to "extend" i64 to i32.
Allows an enum with a discriminant to use any of the primitive integer
types to store it. By default the smallest usable type is chosen, but
this can be overridden with an attribute: `#[repr(int)]` etc., or
`#[repr(C)]` to match the target's C ABI for the equivalent C enum.
This commit breaks a few things, due to transmutes that now no longer
match in size, or u8 enums being passed to C that expects int, or
reflection; later commits on this branch fix them.
It is simply defined as `f64` across every platform right now.
A use case hasn't been presented for a `float` type defined as the
highest precision floating point type implemented in hardware on the
platform. Performance-wise, using the smallest precision correct for the
use case greatly saves on cache space and allows for fitting more
numbers into SSE/AVX registers.
If there was a use case, this could be implemented as simply a type
alias or a struct thanks to `#[cfg(...)]`.
Closes#6592
The mailing list thread, for reference:
https://mail.mozilla.org/pipermail/rust-dev/2013-July/004632.html
The `noalias` attributes were being set only on function definitions,
not on all declarations. This is harmless for `noalias`, but prevented
some optimization opportunities and is *not* harmless for other
attributes like `sret` with ABI implications.
Closes#9104
- Made naming schemes consistent between Option, Result and Either
- Changed Options Add implementation to work like the maybe monad (return None if any of the inputs is None)
- Removed duplicate Option::get and renamed all related functions to use the term `unwrap` instead
Infers type of constants used as discriminants and ensures they are
integral, instead of forcing them to be a signed integer.
Also, stores discriminant values as uint instead of int interally and
deals with related fallout.
Fixes issue #7994
These blocks were required because previously we could only insert
instructions at the end of blocks, but we wanted to have all allocas in
one place, so they can be collapse. But now we have "direct" access the
the LLVM IR builder and can position it freely. This allows us to use
the same trick that clang uses, which means that we insert a dummy
"marker" instruction to identify the spot at which we want to insert
allocas. We can then later position the IR builder at that spot and
insert the alloca instruction, without any dedicated block.
The block for loading the closure environment can now also go away,
because the function context now provides the toplevel block, and the
translation of the loading happens first, so that's good enough.
Makes the LLVM IR a bit more readable, saving a bunch of branches in the
unoptimized code, which benefits unoptimized builds.
Currently, we always create a dedicated "return" basic block, but when
there's only a single predecessor for that block, it can be merged with
that predecessor. We can achieve that merge by only creating the return
block on demand, avoiding its creation when its not required.
Reduces the pre-optimization size of librustc.ll created with --passes ""
by about 90k lines which equals about 4%.
We currently still handle immediate return values a lot like
non-immediate ones. We provide a slot for them and store them into
memory, often just to immediately load them again. To improve this
situation, trans_call_inner has to return a Result which contains the
immediate return value.
Also, it also needs to accept "No destination" in addition to just
SaveIn and Ignore. Since "No destination" isn't something that fits
well into the Dest type, I've chosen to simply use Option<Dest>
instead, paired with an assertion that checks that "None" is only
allowed for immediate return values.
