This function isn't strictly tied to LLVM (it's more of a utility) and
it's now near an analogous, almost identical `filename_for_input` (for
rlibs and so forth).
Also this means not depending on the backend when one wants to know the
accurate .rmeta output filename.
move CTFE engine snapshot state out of miri engine into CTFE machine instance
It still lives in the `interpret` module as it needs access to all sorts of private stuff. Also rename a thing to make @eddyb happy :D
The goal was not to change any behavior.
incr.comp.: Allow for more fine-grained testing of CGU reuse and use it to test incremental ThinLTO.
This adds some tests specifically targeted at incremental ThinLTO, plus the infrastructure for tracking the kind of cache hit/miss we had for a given CGU. @alexcrichton, let me know if you can think of any more tests to add. ThinLTO works rather reliably for small functions, so we should be able to test it in a robust way.
I think after this lands it might time for a "Help us test incremental ThinLTO" post on irlo.
r? @alexcrichton
Implement `MaybeUninit`
This PR:
- Adds `MaybeUninit` (see #53491) to `{core,std}::mem`.
- Makes `mem::{uninitialized,zeroed}` panic when they are used to instantiate an uninhabited type.
- Does *not* deprecate `mem::{uninitialized,zeroed}` just yet. As per https://github.com/rust-lang/rust/issues/53491#issuecomment-414147666, we should not deprecate them until `MaybeUninit` is stabilized.
- It replaces uses of `mem::{uninitialized,zeroed}` in core and alloc with `MaybeUninit`.
There are still several instances of `mem::{uninitialized,zeroed}` in `std` that *this* PR doesn't address.
r? @RalfJung
cc @eddyb you may want to look at the new panicking logic
NLL: disallow creation of immediately unusable variables
Fix#53695
Original description follows
----
This WIP PR is for discussing the impact of fixing #53695 by injecting a fake read in let patterns.
(Travis will fail, at least the `mir-opt` suite is failing in its current state)
Enable fatal warnings for the wasm32 linker
Historically LLD has emitted warnings for various reasons but all the bugs have
since been fixed (yay!) and by enabling fatal warnings we should be able to head
off bugs like #53390 sooner.
Currently we have two files implementing bitsets (and 2D bit matrices).
This commit combines them into one, taking the best features from each.
This involves renaming a lot of things. The high level changes are as
follows.
- bitvec.rs --> bit_set.rs
- indexed_set.rs --> (removed)
- BitArray + IdxSet --> BitSet (merged, see below)
- BitVector --> GrowableBitSet
- {,Sparse,Hybrid}IdxSet --> {,Sparse,Hybrid}BitSet
- BitMatrix --> BitMatrix
- SparseBitMatrix --> SparseBitMatrix
The changes within the bitset types themselves are as follows.
```
OLD OLD NEW
BitArray<C> IdxSet<T> BitSet<T>
-------- ------ ------
grow - grow
new - (remove)
new_empty new_empty new_empty
new_filled new_filled new_filled
- to_hybrid to_hybrid
clear clear clear
set_up_to set_up_to set_up_to
clear_above - clear_above
count - count
contains(T) contains(&T) contains(T)
contains_all - superset
is_empty - is_empty
insert(T) add(&T) insert(T)
insert_all - insert_all()
remove(T) remove(&T) remove(T)
words words words
words_mut words_mut words_mut
- overwrite overwrite
merge union union
- subtract subtract
- intersect intersect
iter iter iter
```
In general, when choosing names I went with:
- names that are more obvious (e.g. `BitSet` over `IdxSet`).
- names that are more like the Rust libraries (e.g. `T` over `C`,
`insert` over `add`);
- names that are more set-like (e.g. `union` over `merge`, `superset`
over `contains_all`, `domain_size` over `num_bits`).
Also, using `T` for index arguments seems more sensible than `&T` --
even though the latter is standard in Rust collection types -- because
indices are always copyable. It also results in fewer `&` and `*`
sigils in practice.
Historically LLD has emitted warnings for various reasons but all the bugs have
since been fixed (yay!) and by enabling fatal warnings we should be able to head
off bugs like #53390 sooner.
Allow for opting out of ThinLTO and clean up LTO related cli flag handling.
It turns out that there currently is no way to explicitly disable ThinLTO (except for the nightly-only `-Zthinlto` flag). This PR extends `-C lto` to take `yes` and `no` in addition to `thin` and `fat`. It should be backwards compatible.
It also cleans up how LTO mode selection is handled.
Note that merging the PR in the current state would make the new values for `-C lto` available on the stable channel. I think that would be fine but maybe some team should vote on it.
Fix a few AMDGPU related issues
* AMDGPU ignores `noinline` and sadly doesn't clear the attribute when it slaps `alwaysinline` on everything,
* an AMDGPU related load bit range metadata assertion,
* I didn't enable the `amdgpu` component in the `librustc_llvm` build script,
* Add AMDGPU call abi info.
rustc_codegen_llvm: don't assume offsets are always aligned.
Fixes#53728 by taking into account not just overall type alignment and the field's alignment when determining whether a field is aligned or not ("packed"), but also the field's offset within the type.
Previously, rustc assumed that the offset was always at least as aligned as `min(struct.align, field.align)`. However, there's no real reason to have that assumption, and it obviously can't always be true after we implement `#[repr(align(N), pack(K))]`. There's also a case today where that assumption is not true, involving niche discriminants in enums:
Suppose that we have the code in #53728:
```Rust
#[repr(u16)]
enum DeviceKind {
Nil = 0,
}
#[repr(packed)]
struct DeviceInfo {
endianness: u8,
device_kind: DeviceKind,
}
struct Wrapper {
device_info: DeviceInfo,
data: u32
}
```
Observe the layout of `Option<Wrapper>`. It has an alignment of 4 because of the `u32`. `device_info.device_kind` is a good niche field to use, which means the enum ends up with this layout:
```
size = 8
align = 4
fields = [
{ offset=1, type=u16 } // discriminant, .<Some>.device_info.device_kind
]
```
And here we have an discriminant with alignment 2 (`u16`) but offset 1.
rustc: Prepare the `atomics` feature for wasm
This commit adds a few changes for atomic instructions on the
`wasm32-unknown-unknown` target. Atomic instructions are not yet stable in
WebAssembly itself but there are multiple implementations and LLVM has support
for the proposed instruction set, so let's work on exposing it!
Here there are a few inclusions:
* The `atomics` feature was whitelisted for LLVM, allowing code in Rust to
enable/disable/gate on this.
* The `singlethread` option is turned off for wasm when the `atomics` feature is
enabled. This means that by default wasm won't be lowering with atomics, but
when atomics are enabled globally we'll turn off single-threaded mode to
actually codegen atomics. This probably isn't what we'll want in the long term
but for now it should work.
* Finally the maximum atomic width is increased to 64 to reflect the current
wasm spec.
This commit adds a few changes for atomic instructions on the
`wasm32-unknown-unknown` target. Atomic instructions are not yet stable in
WebAssembly itself but there are multiple implementations and LLVM has support
for the proposed instruction set, so let's work on exposing it!
Here there are a few inclusions:
* The `atomics` feature was whitelisted for LLVM, allowing code in Rust to
enable/disable/gate on this.
* The `singlethread` option is turned off for wasm when the `atomics` feature is
enabled. This means that by default wasm won't be lowering with atomics, but
when atomics are enabled globally we'll turn off single-threaded mode to
actually codegen atomics. This probably isn't what we'll want in the long term
but for now it should work.
* Finally the maximum atomic width is increased to 64 to reflect the current
wasm spec.
Use FxHash{Map,Set} instead of the default Hash{Map,Set} everywhere in rustc.
Most of the compiler uses the `Fx` hasher but some places ended up with the default one.
Fix warnings about the `native` target-cpu
This fixes a regression from #53031 where specifying `-C target-cpu=native` is
printing a lot of warnings from LLVM about `native` being an unknown CPU. It
turns out that `native` is indeed an unknown CPU and we have to perform a
mapping to an actual CPU name, but this mapping is only performed in one
location rather than all locations we inform LLVM about the target CPU.
This commit centralizes the mapping of `native` to LLVM's value of the native
CPU, ensuring that all locations we inform LLVM about the `target-cpu` it's
never `native`.
Closes#53322
