This commit removes all the old casting/generic traits from `std::num` that are
no longer in use by the standard library. This additionally removes the old
`strconv` module which has not seen much use in quite a long time. All generic
functionality has been supplanted with traits in the `num` crate and the
`strconv` module is supplanted with the [rust-strconv crate][rust-strconv].
[rust-strconv]: https://github.com/lifthrasiir/rust-strconv
This is a breaking change due to the removal of these deprecated crates, and the
alternative crates are listed above.
[breaking-change]
Loading from and storing to small aggregates happens by casting the
aggregate pointer to an appropriately sized integer pointer to avoid
the usage of first class aggregates which would lead to less optimized
code.
But this means that, for example, a tuple of type (i16, i16) will be
loading through an i32 pointer and because we currently don't provide
alignment information LLVM assumes that the load should use the ABI
alignment for i32 which would usually be 4 byte alignment. But the
alignment requirement for the (i16, i16) tuple will usually be just 2
bytes, so we're overestimating alignment, which invokes undefined
behaviour.
Therefore we must emit appropriate alignment information for
stores/loads through such casted pointers.
Fixes#23431
I doubt this PR is ready to merge as-is, for a couple reasons:
* There are no tests for this change. I'm not sure how to add tests for this change, as it modifies the C ABI for a cross-compilation target. Anecdotally, I have an iOS library I've been working on, and before this change, it crashes running on an arm64 device due to bad calling conventions (a simplified example is in #24154), and after this change, it runs correctly.
* This is my first foray into LLVM. I did my best to reimplement what Clang does for AArch64 codegen (https://github.com/llvm-mirror/clang/blob/master/lib/CodeGen/TargetInfo.cpp), particularly in `ABIInfo::isHomogeneousAggregate`, `AArch64ABIInfo::isHomogeneousAggregateBaseType`, and `AArch64ABIInfo::isHomogeneousAggregateSmallEnough`, but I'm not confident I got a complete translation, particularly because Clang includes a lot of checks that I don't believe are necessary for rustc.
Fixes#24154.
We provide tools to tell what exact symbols to emit for any fn or static, but
don’t quite check if that won’t cause any issues later on. Some of the issues
include LLVM mangling our names again and our names pointing to wrong locations,
us generating dumb foreign call wrappers, linker errors, extern functions
resolving to different symbols altogether (`extern {fn fail();} fail();` in some
cases calling `fail1()`), etc.
Before the commit we had a function called `note_unique_llvm_symbol`, so it is
clear somebody was aware of the issue at some point, but the function was barely
used, mostly in irrelevant locations.
Along with working on it I took liberty to start refactoring trans/base into
a few smaller modules. The refactoring is incomplete and I hope I will find some
motivation to carry on with it.
This is possibly a [breaking-change] because it makes dumbly written code
properly invalid.
This fixes all those issues about incorrect use of #[no_mangle] being not reported/misreported/ICEd by the compiler.
NB. This PR does not attempt to tackle the parallel codegen issue that was mentioned in https://github.com/rust-lang/rust/pull/22811, but I believe it should be very straightforward in a follow up PR by modifying `trans::declare::get_defined_value` to look at all the contexts.
cc @alexcrichton @huonw @nrc because you commented on the original RFC issue.
EDIT: wow, this became much bigger than I initially intended.
Implements an intrinsic for extracting the value of the discriminant
enum variant values. For non-enum types, this returns zero, otherwise it
returns the value we use for discriminant comparisons. This means that
enum types that do not have a discriminant will also work in this
arrangement.
This is (at least part of) the work on Issue #24263
In addition to being nicer, this also allows you to use `sum` and `product` for
iterators yielding custom types aside from the standard integers.
Due to removing the `AdditiveIterator` and `MultiplicativeIterator` trait, this
is a breaking change.
[breaking-change]
We provide tools to tell what exact symbols to emit for any fn or static, but
don’t quite check if that won’t cause any issues later on. Some of the issues
include LLVM mangling our names again and our names pointing to wrong locations,
us generating dumb foreign call wrappers, linker errors, extern functions
resolving to different symbols altogether (extern {fn fail();} fail(); in some
cases calling fail1()), etc.
Before the commit we had a function called note_unique_llvm_symbol, so it is
clear somebody was aware of the issue at some point, but the function was barely
used, mostly in irrelevant locations.
Along with working on it I took liberty to start refactoring trans/base into
a few smaller modules. The refactoring is incomplete and I hope I will find some
motivation to carry on with it.
This is possibly a [breaking-change] because it makes dumbly written code
properly invalid.
This PR solves #21559 by making sure that unreachable if-expressions are not further translated.
Could someone who knows their way around `trans` take a look at the changes in `controlflow.rs`? I'm not sure if any other code relies on any side-effects of translating unreachable things.
cc @nikomatsakis @nrc @eddyb
const_eval : add overflow-checking for {`+`, `-`, `*`, `/`, `<<`, `>>`}.
One tricky detail here: There is some duplication of labor between `rustc::middle::const_eval` and `rustc_trans::trans::consts`. It might be good to explore ways to try to factor out the common structure to the two passes (by abstracting over the particular value-representation used in the compile-time interpreter).
----
Update: Rebased atop #23841Fix#22531Fix#23030Fix#23221Fix#23235
Add option-returning variants to `const_to_int`/`const_to_uint` that
never assert fail. (These will be used for overflow checking from
rustc_trans::trans::consts.)
This commit stabilizes the `std::num` module:
* The `Int` and `Float` traits are deprecated in favor of (1) the
newly-added inherent methods and (2) the generic traits available in
rust-lang/num.
* The `Zero` and `One` traits are reintroduced in `std::num`, which
together with various other traits allow you to recover the most
common forms of generic programming.
* The `FromStrRadix` trait, and associated free function, is deprecated
in favor of inherent implementations.
* A wide range of methods and constants for both integers and floating
point numbers are now `#[stable]`, having been adjusted for integer
guidelines.
* `is_positive` and `is_negative` are renamed to `is_sign_positive` and
`is_sign_negative`, in order to address #22985
* The `Wrapping` type is moved to `std::num` and stabilized;
`WrappingOps` is deprecated in favor of inherent methods on the
integer types, and direct implementation of operations on
`Wrapping<X>` for each concrete integer type `X`.
Closes#22985Closes#21069
[breaking-change]
r? @alexcrichton
This commit stabilizes the `std::num` module:
* The `Int` and `Float` traits are deprecated in favor of (1) the
newly-added inherent methods and (2) the generic traits available in
rust-lang/num.
* The `Zero` and `One` traits are reintroduced in `std::num`, which
together with various other traits allow you to recover the most
common forms of generic programming.
* The `FromStrRadix` trait, and associated free function, is deprecated
in favor of inherent implementations.
* A wide range of methods and constants for both integers and floating
point numbers are now `#[stable]`, having been adjusted for integer
guidelines.
* `is_positive` and `is_negative` are renamed to `is_sign_positive` and
`is_sign_negative`, in order to address #22985
* The `Wrapping` type is moved to `std::num` and stabilized;
`WrappingOps` is deprecated in favor of inherent methods on the
integer types, and direct implementation of operations on
`Wrapping<X>` for each concrete integer type `X`.
Closes#22985Closes#21069
[breaking-change]
r? @alexcrichton
This commit stabilizes the `std::num` module:
* The `Int` and `Float` traits are deprecated in favor of (1) the
newly-added inherent methods and (2) the generic traits available in
rust-lang/num.
* The `Zero` and `One` traits are reintroduced in `std::num`, which
together with various other traits allow you to recover the most
common forms of generic programming.
* The `FromStrRadix` trait, and associated free function, is deprecated
in favor of inherent implementations.
* A wide range of methods and constants for both integers and floating
point numbers are now `#[stable]`, having been adjusted for integer
guidelines.
* `is_positive` and `is_negative` are renamed to `is_sign_positive` and
`is_sign_negative`, in order to address #22985
* The `Wrapping` type is moved to `std::num` and stabilized;
`WrappingOps` is deprecated in favor of inherent methods on the
integer types, and direct implementation of operations on
`Wrapping<X>` for each concrete integer type `X`.
Closes#22985Closes#21069
[breaking-change]
This functions swaps the order of arguments to a few functions that previously
took (output, input) parameters, but now take (input, output) parameters (in
that order).
The affected functions are:
* ptr::copy
* ptr::copy_nonoverlapping
* slice::bytes::copy_memory
* intrinsics::copy
* intrinsics::copy_nonoverlapping
Closes#22890
[breaking-change]
This functions swaps the order of arguments to a few functions that previously
took (output, input) parameters, but now take (input, output) parameters (in
that order).
The affected functions are:
* ptr::copy
* ptr::copy_nonoverlapping
* slice::bytes::copy_memory
* intrinsics::copy
* intrinsics::copy_nonoverlapping
Closes#22890
[breaking-change]
the plan is to treat all binary operators as if they were overloaded,
relying on the fact that we have impls for all the builtin scalar
operations (and no more). But then during writeback we clear the
overload if the types correspond to a builtin op.
This strategy allows us to avoid having to know the types of the
operands ahead of time. It also avoids us overspecializing as we did in
the past.
When testing whether a default method predicates are satisfiable,
combine normalization with this check so that we also skip the
default method if normalization fails. Fixes#23485.
r? @nrc (I tried to address your nit from before as well)
Refactored code so that the drop-flag values for initialized
(`DTOR_NEEDED`) versus dropped (`DTOR_DONE`) are given explicit names.
Add `mem::dropped()` (which with `DTOR_DONE == 0` is semantically the
same as `mem::zeroed`, but the point is that it abstracts away from
the particular choice of value for `DTOR_DONE`).
Filling-drop needs to use something other than `ptr::read_and_zero`,
so I added such a function: `ptr::read_and_drop`. But, libraries
should not use it if they can otherwise avoid it.
Fixes to tests to accommodate filling-drop.
The reassignment checker effectively only checks whether the last
assignment in a body affects the discriminant, but it should of course
check all the assignments.
Fixes#23698
The reassignment checker effectively only checks whether the last
assignment in a body affects the discriminant, but it should of course
check all the assignments.
Fixes#23698
The primary motivation here is to sidestep #19032 -- for a time, I thought that we should improve coherence or otherwise extend the language, but I now think that any such changes will require more time to bake. In the meantime, inheritance amongst the fn traits is both logically correct *and* a simple solution to that obstacle. This change introduces inheritance and modifies the compiler so that it can properly generate impls for closures and fns.
Things enabled by this PR (but not included in this PR):
1. An impl of `FnMut` for `&mut F` where `F : FnMut` (https://github.com/rust-lang/rust/issues/23015).
2. A better version of `Thunk` I've been calling `FnBox`.
I did not include either of these in the PR because:
1. Adding the impls in 1 currently induces a coherence conflict with the pattern trait. This is interesting and merits some discussion.
2. `FnBox` deserves to be a PR of its own.
The main downside to this design is (a) the need to write impls by hand; (b) the possibility of implementing `FnMut` with different semantics from `Fn`, etc. Point (a) is minor -- in particular, it does not affect normal closure usage -- and could be addressed in the future in many ways (better defaults; convenient macros; specialization; etc). Point (b) is unfortunate but "just a bug" from my POV, and certainly not unique to these traits (c.f. Copy/Clone, PartialEq/Eq, etc). (Until we lift the feature-gate on implementing the Fn traits, in any case, there is room to correct both of these if we find a nice way.)
Note that I believe this change is reversible in the future if we decide on another course of action, due to the feature gate on implementing the `Fn` traits, though I do not (currently) think we should reverse it.
Fixes#18835.
r? @nrc
This permits all coercions to be performed in casts, but adds lints to warn in those cases.
Part of this patch moves cast checking to a later stage of type checking. We acquire obligations to check casts as part of type checking where we previously checked them. Once we have type checked a function or module, then we check any cast obligations which have been acquired. That means we have more type information available to check casts (this was crucial to making coercions work properly in place of some casts), but it means that casts cannot feed input into type inference.
[breaking change]
* Adds two new lints for trivial casts and trivial numeric casts, these are warn by default, but can cause errors if you build with warnings as errors. Previously, trivial numeric casts and casts to trait objects were allowed.
* The unused casts lint has gone.
* Interactions between casting and type inference have changed in subtle ways. Two ways this might manifest are:
- You may need to 'direct' casts more with extra type information, for example, in some cases where `foo as _ as T` succeeded, you may now need to specify the type for `_`
- Casts do not influence inference of integer types. E.g., the following used to type check:
```
let x = 42;
let y = &x as *const u32;
```
Because the cast would inform inference that `x` must have type `u32`. This no longer applies and the compiler will fallback to `i32` for `x` and thus there will be a type error in the cast. The solution is to add more type information:
```
let x: u32 = 42;
let y = &x as *const u32;
```
The method with which backwards compatibility was retained ended up leading to
documentation that rustdoc didn't handle well and largely ended up confusing.
For the rust-call ABI, the last function argument is a tuple that gets
untupled for the actual call. For bare functions using this ABI, the
code has access to the tuple, so we need to tuple the arguments again.
But closures can't actually access the tuple. Their arguments map to the
elements in the tuple. So what we currently do is to tuple the arguments
and then immediately untuple them again, which is pretty useless and we
can just omit it.
This is a [breaking-change]. When indexing a generic map (hashmap, etc) using the `[]` operator, it is now necessary to borrow explicitly, so change `map[key]` to `map[&key]` (consistent with the `get` routine). However, indexing of string-valued maps with constant strings can now be written `map["abc"]`.
r? @japaric
cc @aturon @Gankro
This fixes a bug in LLVM IR generation for in-line assembly where Rust would always use the host clobbers instead of target clobbers.
I also took this opportunity to clean/simplify the ```trans_inline_asm``` function.
This is my first Rust pull request; please let me know if I'm missing anything.
This commit:
* Introduces `std::convert`, providing an implementation of
RFC 529.
* Deprecates the `AsPath`, `AsOsStr`, and `IntoBytes` traits, all
in favor of the corresponding generic conversion traits.
Consequently, various IO APIs now take `AsRef<Path>` rather than
`AsPath`, and so on. Since the types provided by `std` implement both
traits, this should cause relatively little breakage.
* Deprecates many `from_foo` constructors in favor of `from`.
* Changes `PathBuf::new` to take no argument (creating an empty buffer,
as per convention). The previous behavior is now available as
`PathBuf::from`.
* De-stabilizes `IntoCow`. It's not clear whether we need this separate trait.
Closes#22751Closes#14433
[breaking-change]
impls.
This requires:
1. modifying trait selection a bit so that when we synthesize impls for
fn pointers and closures;
2. adding code to trans so that we can synthesize a `FnMut`/`FnOnce`
impl for a `Fn` closure and so forth.
Boolean values and small aggregates have a different type in args/allocas than
in SSA values but the intrinsics for volatile and atomic ops were
missing the necessary casts to handle that.
Fixes#23550
For the rust-call ABI, the last function argument is a tuple that gets
untupled for the actual call. For bare functions using this ABI, the
code has access to the tuple, so we need to tuple the arguments again.
But closures can't actually access the tuple. Their arguments map to the
elements in the tuple. So what we currently do is to tuple the arguments
and then immediately untuple them again, which is pretty useless and we
can just omit it.
After this patch code like `let ref a = *"abcdef"` doesn't cause ICE anymore.
Required for #23121
There are still places in rustc_trans where pointers are always assumed to be thin. In particular, #19064 is not resolved by this patch.
The method with which backwards compatibility was retained ended up leading to
documentation that rustdoc didn't handle well and largely ended up confusing.
Boolean values and small aggregates have a different type in
args/allocas than in SSA values but the intrinsics for volatile and
atomic ops were missing the necessary casts to handle that.
Fixes#23550
This includes a slight refactoring of the `cast_shift_rhs` and related
functions in `trans::base`, so that I can call them from much later in
the compiler's control flow (so that we can clearly dilineate where
automatic conversions of the RHS occur, versus where we check it).
The rhs-checking and fallback-masking is generalized to 8- and 16-bit
values, and the fallback-masking is turned on unconditionally.
Fix#10183.
Is this a [breaking-change]? I would argue it is not; it only adds a
strict definition to what was previously undefined behavior; however,
there might be code that was e.g. assuming that `1_i8 << 17` yields 0.
(This happens in certain contexts and at certain optimization levels.)
* no_split_stack was renamed to no_stack_check
* deriving was renamed to derive
* `use foo::mod` was renamed to `use foo::self`;
* legacy lifetime definitions in closures have been replaced with `for` syntax
* `fn foo() -> &A + B` has been deprecated for some time (needs parens)
* Obsolete `for Sized?` syntax
* Obsolete `Sized? Foo` syntax
* Obsolete `|T| -> U` syntax
This patch changes the type of byte string literals from `&[u8]` to `&[u8; N]`.
It also implements some necessary traits (`IntoBytes`, `Seek`, `Read`, `BufRead`) for fixed-size arrays (also related to #21725) and adds test for #17233, which seems to be resolved.
Fixes#18465
[breaking-change]
