Handle integer-extending for C ABI
We need to supply sext/zext attributes to LLVM to ensure that arguments
are extended to the appropriate width in the correct way.
Most platforms extend integers less than 32 bits, though not all.
Only allow using the atomic intrinsics on integer types
Using these with non-integer types results in LLVM asserts. Atomic operations on non-integer types will require values be transmuted into an integer type of suitable size.
This doesn't affect the standard library since `AtomicBool` and `AtomicPtr` currently use `usize` for atomic operations.
r? @eddyb
We need to supply sext/zext attributes to LLVM to ensure that arguments
are extended to the appropriate width in the correct way.
Most platforms extend integers less than 32 bits, though not all.
rBreak Critical Edges and other MIR work
This PR is built on top of #32080.
This adds the basic depth-first traversals for MIR, preorder, postorder and reverse postorder. The MIR blocks are now translated using reverse postorder. There is also a transform for breaking critical edges, which includes the edges from `invoke`d calls (`Drop` and `Call`), to account for the fact that we can't add code after an `invoke`. It also stops generating the intermediate block (since the transform essentially does it if necessary already).
The kinds of cases this deals with are difficult to produce, so the test is the one I managed to get. However, it seems to bootstrap with `-Z orbit`, which it didn't before my changes.
/# This is a combination of 16 commits.
/# The first commit's message is:
allow RUST_BACKTRACE=disabled to act as if unset
When RUST_BACKTRACE is set to "disabled" then this acts as if the env.
var is unset.
/# This is the 2nd commit message:
case insensitive "DiSaBLeD" RUST_BACKTRACE value
previously it expected a lowercase "disabled" to treat the env. var as
unset
/# This is the 3rd commit message:
RUST_BACKTRACE=0 acts as if unset
previously RUST_BACKTRACE=disabled was doing the same thing
/# This is the 4th commit message:
RUST_BACKTRACE=0|n|no|off acts as if unset
previously only RUST_BACKTRACE=0 acted as if RUST_BACKTRACE was unset
Now added more options (case-insensitive): 'n','no' and 'off'
eg. RUST_BACKTRACE=oFF
/# This is the 5th commit message:
DRY on the value of 2
DRY=don't repeat yourself
Because having to remember to keep the two places of '2' in sync is not
ideal, even though this is a simple enough case.
/# This is the 6th commit message:
Revert "DRY on the value of 2"
This reverts commit 95a0479d5cf72a2b2d9d21ec0bed2823ed213fef.
Nevermind this DRY on 2, because we already have a RY on 1,
besides the code is less readable this way...
/# This is the 7th commit message:
attempt to document unsetting RUST_BACKTRACE
/# This is the 8th commit message:
curb allocations when checking for RUST_BACKTRACE
this means we don't check for case-insensitivity anymore
/# This is the 9th commit message:
as decided, RUST_BACKTRACE=0 turns off backtrace
/# This is the 10th commit message:
RUST_TEST_NOCAPTURE=0 acts as if unset
(that is, capture is on)
Any other value acts as if nocapture is enabled (that is, capture is off)
/# This is the 11th commit message:
update other RUST_TEST_NOCAPTURE occurrences
apparently only one place needs updating
/# This is the 12th commit message:
update RUST_BACKTRACE in man page
/# This is the 13th commit message:
handle an occurrence of RUST_BACKTRACE
/# This is the 14th commit message:
ensure consistency with new rules for backtrace
/# This is the 15th commit message:
a more concise comment for RUST_TEST_NOCAPTURE
/# This is the 16th commit message:
update RUST_TEST_NOCAPTURE in man page
Integrate privacy into field and method selection
This PR integrates privacy checking into field and method selection so that an inaccessible field/method can not stop an accessible field/method from being used (fixes#12808 and fixes#22684).
r? @eddyb
diagnostics: make paths to external items more visible
This PR changes the reported path for an external item so that it is visible from at least one local module (i.e. it does not use any inaccessible external modules) if possible. If the external item's crate was declared with an `extern crate`, the path is guarenteed to use the `extern crate`.
Fixes#23224, fixes#23355, fixes#26635, fixes#27165.
r? @nrc
Use weak_odr linkage when reusing definitions across codegen units
When reuing a definition across codegen units, we obviously cannot use
internal linkage, but using external linkage means that we can end up
with multiple conflicting definitions of a single symbol across
multiple crates. Since the definitions should all be equal
semantically, we can use weak_odr linkage to resolve the situation.
Fixes#32518
r? @nikomatsakis
When reuing a definition across codegen units, we obviously cannot use
internal linkage, but using external linkage means that we can end up
with multiple conflicting definitions of a single symbol across
multiple crates. Since the definitions should all be equal
semantically, we can use weak_odr linkage to resolve the situation.
Fixes#32518
Restrict constants in patterns
This implements [RFC 1445](https://github.com/rust-lang/rfcs/blob/master/text/1445-restrict-constants-in-patterns.md). The primary change is to limit the types of constants used in patterns to those that *derive* `Eq` (note that implementing `Eq` is not sufficient). This has two main effects:
1. Floating point constants are linted, and will eventually be disallowed. This is because floating point constants do not implement `Eq` but only `PartialEq`. This check replaces the existing special case code that aimed to detect the use of `NaN`.
2. Structs and enums must derive `Eq` to be usable within a match.
This is a [breaking-change]: if you encounter a problem, you are most likely using a constant in an expression where the type of the constant is some struct that does not currently implement
`Eq`. Something like the following:
```rust
struct SomeType { ... }
const SOME_CONST: SomeType = ...;
match foo {
SOME_CONST => ...
}
```
The easiest and most future compatible fix is to annotate the type in question with `#[derive(Eq)]` (note that merely *implementing* `Eq` is not enough, it must be *derived*):
```rust
struct SomeType { ... }
const SOME_CONST: SomeType = ...;
match foo {
SOME_CONST => ...
}
```
Another good option is to rewrite the match arm to use an `if` condition (this is also particularly good for floating point types, which implement `PartialEq` but not `Eq`):
```rust
match foo {
c if c == SOME_CONST => ...
}
```
Finally, a third alternative is to tag the type with `#[structural_match]`; but this is not recommended, as the attribute is never expected to be stabilized. Please see RFC #1445 for more details.
cc https://github.com/rust-lang/rust/issues/31434
r? @pnkfelix
resolve: Minimize hacks in name resolution of primitive types
When resolving the first unqualified segment in a path with `n` segments and `n - 1` associated item segments, e.g. (`a` or `a::assoc` or `a::assoc::assoc` etc) try to resolve `a` without considering primitive types first. If the "normal" lookup fails or results in a module, then try to resolve `a` as a primitive type as a fallback.
This way backward compatibility is respected, but the restriction from E0317 can be lifted, i.e. primitive names mostly can be shadowed like any other names.
Furthermore, if names of primitive types are [put into prelude](https://github.com/petrochenkov/rust/tree/prim2) (now it's possible to do), then most of names will be resolved in conventional way and amount of code relying on this fallback will be greatly reduced. Although, it's not entirely convenient to put them into prelude right now due to temporary conflicts like `use prelude::v1::*; use usize;` in libcore/libstd, I'd better wait for proper glob shadowing before doing it.
I wish the `no_prelude` attribute were unstable as intended :(
cc @jseyfried @arielb1
r? @eddyb
Link guards cause problems in some specific scenarios on windows because
they force libcore to be instantiated, since we do not GC functions
effectively on windows.
The changes here are two:
1. disable core for rsbegin/rsend
2. make panic_fmt an extern fn for smallest-hello-world so that it
is not marked as "internal" for LLVM
Annotate run-pass/backtrace with #[rustc_no_mir] on MSVC.
Fixes#32384 by not using MIR on MSVC for the functions in the path of the backtrace.
This is the known blocker for the MSVC MIR builder, hopefully the only one overall.
r? @alexcrichton Confirmed to work on a nightly, by @retep998.
Fix const trans
Fix#30615.
The idea was that when there are N autoderefs, first do N-1 derefs and check for autoref. If there is autoref, done, if not, do one more deref. But when N is zero, doing one more deref is wrong.
Automated conversion using the untry tool [1] and the following command:
```
$ find -name '*.rs' -type f | xargs untry
```
at the root of the Rust repo.
[1]: https://github.com/japaric/untry
Improve time complexity of equality relations
This PR adds a `UnificationTable` to the `TypeVariableTable` type which is used store information about variable equality instead of just storing them in a vector for later processing. By using a `UnificationTable` equality relations can be resolved in O(n) (for all realistic values of n) rather than O(n!) which can give massive speedups in certain cases (see combine as an example).
Link to combine: https://github.com/Marwes/combine
This PR adds a `UnificationTable` to the `TypeVariableTable` type which
is used store information about variable equality instead of just
storing them in a vector for later processing. By using a
`UnificationTable` equality relations can be resolved in O(n) (for all
realistic values of n) rather than O(n!) which can give massive
speedups in certain cases (see combine as an example).
Link to combine: https://github.com/Marwes/combine
Fix mis-uses of projection mode
A couple of places where we construct a fresh inference context were
incorrectly assuming that we were past coherence checking. This commit
corrects them to use `Topmost` rather than `AnyFinal` as the projection mode.
Fixes#32324
r? @nikomatsakis
A couple of places where we construct a fresh inference context were
incorrectly assuming that we were past coherence checking. This commit
corrects them to use `Topmost` rather than `AnyFinal` as the projection mode.
Fixes#32324
Fix floating point fast-math intrinsics
The implementation did not handle the case where both operands were constants, which caused an llvm assertion:
```
rustc: //buildslave//rust-buildbot//slave//nightly-dist-rustc-musl-linux//build//src//llvm//include/llvm/Support/Casting.h:237:
typename llvm::cast_retty<X, Y*>::ret_type llvm::cast(Y*) [with X = llvm::Instruction; Y = llvm::Value; typename llvm::cast_retty<X, Y*>::ret_type = llvm::Instruction*]:
Assertion `isa<X>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
```
