The previous manual parsing of `serde_json::Value` was a lot of
complicated code and extremely error-prone. It was full of janky
behavior like sometimes ignoring type errors, sometimes erroring for
type errors, sometimes warning for type errors, and sometimes just
ICEing for type errors (the icing on the top).
Additionally, many of the error messages about allowed values were out
of date because they were in a completely different place than the
FromStr impls. Overall, the system caused confusion for users.
I also found the old deserialization code annoying to read. Whenever a
`key!` invocation was found, one had to first look for the right macro
arm, and no go to definition could help.
This PR replaces all this manual parsing with a 2-step process involving
serde.
First, the string is parsed into a `TargetSpecJson` struct. This struct
is a 1:1 representation of the spec JSON. It already parses all the
enums and is very simple to read and write.
Then, the fields from this struct are copied into the actual `Target`.
The reason for this two-step process instead of just serializing into a
`Target` is because of a few reasons
1. There are a few transformations performed between the two formats
2. The default logic is implemented this way. Otherwise all the default
field values would have to be spelled out again, which is
suboptimal. With this logic, they fall out naturally, because
everything in the json struct is an `Option`.
Overall, the mapping is pretty simple, with the vast majority of fields
just doing a 1:1 mapping that is captured by two macros. I have
deliberately avoided making the macros generic to keep them simple.
All the `FromStr` impls now have the error message right inside them,
which increases the chance of it being up to date. Some "`from_str`"
impls were turned into proper `FromStr` impls to support this.
The new code is much less involved, delegating all the JSON parsing
logic to serde, without any manual type matching.
This change introduces a few breaking changes for consumers. While it is
possible to use this format on stable, it is very much subject to
change, so breaking changes are expected. The hope is also that because
of the way stricter behavior, breaking changes are easier to deal with,
as they come with clearer error messages.
1. Invalid types now always error, everywhere. Previously, they would
sometimes error, and sometimes just be ignored (which meant the users
JSON was still broken, just silently!)
2. This now makes use of `deny_unknown_fields` instead of just warning
on unused fields, which was done previously. Serde doesn't make it
easy to get such warning behavior, which was the primary reason that
this now changed. But I think error behavior is very reasonable too.
If someone has random stale fields in their JSON, it is likely
because these fields did something at some point but no longer do,
and the user likely wants to be informed of this so they can figure
out what to do.
This is also relevant for the future. If we remove a field but
someone has it set, it probably makes sense for them to take a look
whether they need this and should look for alternatives, or whether
they can just delete it. Overall, the JSON is made more explicit.
This is the only expected breakage, but there could also be small
breakage from small mistakes. All targets roundtrip though, so it can't
be anything too major.
Enable xgot feature for mips64 musl targets
This was missed in b65c2afdfd9aaee977302516c9ef177861abfe74, which only enabled it for the glibc targets.
I didn't feel comfortable touching the OpenWRT target, whoever maintains that will probably want to take a look whether it is necessary there as well.
This stabilizes a subset of the `-Clinker-features` components on x64 linux:
the lld opt-out.
The opt-in is not stabilized, as interactions with other stable flags require
more internal work, but are not needed for stabilizing using rust-lld by default.
Similarly, since we only switch to rust-lld on x64 linux, the opt-out is
only stabilized there. Other targets still require `-Zunstable-options`
to use it.
Allow custom default address spaces and parse `p-` specifications in the datalayout string
Some targets, such as CHERI, use as default an address space different from the "normal" default address space `0` (in the case of CHERI, [200 is used](https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-877.pdf)). Currently, `rustc` does not allow to specify custom address spaces and does not take into consideration [`p-` specifications in the datalayout string](https://llvm.org/docs/LangRef.html#langref-datalayout).
This patch tries to mitigate these problems by allowing targets to define a custom default address space (while keeping the default value to address space `0`) and adding the code to parse the `p-` specifications in `rustc_abi`. The main changes are that `TargetDataLayout` now uses functions to refer to pointer-related informations, instead of having specific fields for the size and alignment of pointers in the default address space; furthermore, the two `pointer_size` and `pointer_align` fields in `TargetDataLayout` are replaced with an `FxHashMap` that holds info for all the possible address spaces, as parsed by the `p-` specifications.
The potential performance drawbacks of not having ad-hoc fields for the default address space will be tested in this PR's CI run.
r? workingjubilee
This was missed in b65c2afdfd9aaee977302516c9ef177861abfe74, which only
enabled it for the glibc targets.
I didn't feel comfortable touching the OpenWRT target, whoever maintains
that will probably want to take a look whether it is necessary there as
well.
Signed-off-by: Jens Reidel <adrian@travitia.xyz>
setup typos check in CI
This allows to check typos in CI, currently for compiler only (to reduce commit size with fixes). With current setup, exclude list is quite short, so it worth trying?
Also includes commits with actual typo fixes.
MCP: https://github.com/rust-lang/compiler-team/issues/817
typos check currently turned for:
* ./compiler
* ./library
* ./src/bootstrap
* ./src/librustdoc
After merging, PRs which enables checks for other crates (tools) can be implemented too.
Found typos will **not break** other jobs immediately: (tests, building compiler for perf run). Job will be marked as red on completion in ~ 20 secs, so you will not forget to fix it whenever you want, before merging pr.
Check typos: `python x.py test tidy --extra-checks=spellcheck`
Apply typo fixes: `python x.py test tidy --extra-checks=spellcheck:fix` (in case if there only 1 suggestion of each typo)
Current fail in this pr is expected and shows how typo errors emitted. Commit with error will be removed after r+.
make `tidy-alphabetical` use a natural sort
The idea here is that these lines should be correctly sorted, even though a naive string comparison would say they are not:
```
foo2
foo10
```
This is the ["natural sort order"](https://en.wikipedia.org/wiki/Natural_sort_order).
There is more discussion in [#t-compiler/help > tidy natural sort](https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp/topic/tidy.20natural.20sort/with/519111079)
Unfortunately, no standard sorting tools are smart enough to to this automatically (casting some doubt on whether we should make this change). Here are some sort outputs:
```
> cat foo.txt | sort
foo
foo1
foo10
foo2
mp
mp1e2
np",
np1e2",
> cat foo.txt | sort -n
foo
foo1
foo10
foo2
mp
mp1e2
np",
np1e2",
> cat foo.txt | sort -V
foo
foo1
foo2
foo10
mp
mp1e2
np1e2",
np",
```
Disappointingly, "numeric" sort does not actually have the behavior we want. It only sorts by numeric value if the line starts with a number. The "version" sort looks promising, but does something very unintuitive if you look at the final 4 values. None of the other options seem to have the desired behavior in all cases:
```
-b, --ignore-leading-blanks ignore leading blanks
-d, --dictionary-order consider only blanks and alphanumeric characters
-f, --ignore-case fold lower case to upper case characters
-g, --general-numeric-sort compare according to general numerical value
-i, --ignore-nonprinting consider only printable characters
-M, --month-sort compare (unknown) < 'JAN' < ... < 'DEC'
-h, --human-numeric-sort compare human readable numbers (e.g., 2K 1G)
-n, --numeric-sort compare according to string numerical value
-R, --random-sort shuffle, but group identical keys. See shuf(1)
--random-source=FILE get random bytes from FILE
-r, --reverse reverse the result of comparisons
--sort=WORD sort according to WORD:
general-numeric -g, human-numeric -h, month -M,
numeric -n, random -R, version -V
-V, --version-sort natural sort of (version) numbers within text
```
r? ```@Noratrieb``` (it sounded like you know this code?)
Refresh module-level docs for `rustc_target::spec`
We have long since gone on a curveball from the flexible-target-specification RFC by introducing stability and soundness promises to the language and compiler which we often struggle with extending to target-specific implementation details. Indeed, we often *literally cannot*. We also have modified the search algorithm details. Update the comments for `rustc_target::spec` considerably.
Set elf e_flags on ppc64 targets according to abi
(This PR contains the non user-facing changes of https://github.com/rust-lang/rust/pull/142321)
Fixes https://github.com/rust-lang/rust/issues/85589 by making sure that ld.lld errors out instead of generating a broken binary.
Basically the problem is that ld.lld assumes that all ppc64 object files with e_flags=0 are object files which use the ELFv2 ABI (this here is the check https://github.com/llvm/llvm-project/blob/main/lld/ELF/Arch/PPC64.cpp#L639).
This pull request sets the correct e_flags to indicate the used ABI so ld.lld errors out when encountering ELFv1 ABI files instead of generating a broken binary.
For example compare code generation for this program (file name ``min.rs``):
```rust
#![feature(no_core, lang_items, repr_simd)]
#![crate_type = "bin"]
#![no_core]
#![no_main]
#[lang = "sized"]
trait Sized {}
#[lang = "copy"]
trait Copy {}
#[lang = "panic_cannot_unwind"]
pub fn panic() -> ! {
loop {}
}
pub fn my_rad_unmangled_function() {
loop {}
}
pub fn my_rad_function() {
loop {}
}
#[no_mangle]
pub fn _start() {
my_rad_unmangled_function();
my_rad_function();
}
```
Compile with ``rustc --target=powerpc64-unknown-linux-gnu -C linker=ld.lld -C relocation-model=static min.rs``
Before change:
```
$ llvm-objdump -d min
Disassembly of section .text:
000000001001030c <.text>:
...
10010334: 7c 08 02 a6 mflr 0
10010338: f8 21 ff 91 stdu 1, -112(1)
1001033c: f8 01 00 80 std 0, 128(1)
10010340: 48 02 00 39 bl 0x10030378 <_ZN3min25my_rad_unmangled_function17h7471c49af58039f5E>
10010344: 60 00 00 00 nop
10010348: 48 02 00 49 bl 0x10030390 <_ZN3min15my_rad_function17h37112b8fd1008c9bE>
1001034c: 60 00 00 00 nop
...
```
The branch instructions ``bl 0x10030378`` and ``bl 0x10030390`` are jumping into the ``.opd`` section which is data. That is a broken binary (because fixing those branches is the task of the linker).
After change:
```
error: linking with `ld.lld` failed: exit status: 1
|
= note: "ld.lld" "/tmp/rustcNYKZCS/symbols.o" "<1 object files omitted>" "--as-needed" "-L" "/tmp/rustcNYKZCS/raw-dylibs" "-Bdynamic" "--eh-frame-hdr" "-z" "noexecstack" "-L" "<sysroot>/lib/rustlib/powerpc64-unknown-linux-gnu/lib" "-o" "min" "--gc-sections" "-z" "relro" "-z" "now"
= note: some arguments are omitted. use `--verbose` to show all linker arguments
= note: ld.lld: error: /tmp/rustcNYKZCS/symbols.o: ABI version 1 is not supported
```
Which is correct because ld.lld doesn't support ELFv1 ABI.
Apply ABI attributes on return types in `rustc_codegen_cranelift`
- The [x86-64 System V ABI standard](https://gitlab.com/x86-psABIs/x86-64-ABI/-/jobs/artifacts/master/raw/x86-64-ABI/abi.pdf?job=build) doesn't sign/zero-extend integer arguments or return types.
- But the de-facto standard as implemented by Clang and GCC is to sign/zero-extend arguments to 32 bits (but not return types).
- Additionally, Apple targets [sign/zero-extend both arguments and return values to 32 bits](https://developer.apple.com/documentation/xcode/writing-64-bit-intel-code-for-apple-platforms#Pass-arguments-to-functions-correctly).
- However, the `rustc_target` ABI adjustment code currently [unconditionally extends both arguments and return values to 32 bits](e703dff8fe/compiler/rustc_target/src/callconv/x86_64.rs (L240)) on all targets.
- This doesn't cause a miscompilation when compiling with LLVM as LLVM will ignore the `signext`/`zeroext` attribute when applied to return types on non-Apple x86-64 targets.
- Cranelift, however, does not have a similar special case, requiring `rustc` to set the argument extension attribute correctly.
- However, `rustc_codegen_cranelift` doesn't currently apply ABI attributes to return types at all, meaning `rustc_codegen_cranelift` will currently miscompile `i8`/`u8`/`i16`/`u16` returns on x86-64 Apple targets as those targets require sign/zero-extension of return types.
This PR fixes the bug(s) by making the `rustc_target` x86-64 System V ABI only mark return types as sign/zero-extended on Apple platforms, while also making `rustc_codegen_cranelift` apply ABI attributes to return types. The RISC-V and s390x C ABIs also require sign/zero extension of return types, so this will fix those targets when building with `rustc_codegen_cranelift` too.
r? `````@bjorn3`````
add `extern "custom"` functions
tracking issue: rust-lang/rust#140829
previous discussion: https://github.com/rust-lang/rust/issues/140566
In short, an `extern "custom"` function is a function with a custom ABI, that rust does not know about. Therefore, such functions can only be defined with `#[unsafe(naked)]` and `naked_asm!`, or via an `extern "C" { /* ... */ }` block. These functions cannot be called using normal rust syntax: calling them can only be done from inline assembly.
The motivation is low-level scenarios where a custom calling convention is used. Currently, we often pick `extern "C"`, but that is a lie because the function does not actually respect the C calling convention.
At the moment `"custom"` seems to be the name with the most support. That name is not final, but we need to pick something to actually implement this.
r? `@traviscross`
cc `@tgross35`
try-job: x86_64-apple-2
retpoline and retpoline-external-thunk flags (target modifiers) to enable retpoline-related target features
`-Zretpoline` and `-Zretpoline-external-thunk` flags are target modifiers (tracked to be equal in linked crates).
* Enables target features for `-Zretpoline-external-thunk`:
`+retpoline-external-thunk`, `+retpoline-indirect-branches`, `+retpoline-indirect-calls`.
* Enables target features for `-Zretpoline`:
`+retpoline-indirect-branches`, `+retpoline-indirect-calls`.
It corresponds to clang -mretpoline & -mretpoline-external-thunk flags.
Also this PR forbids to specify those target features manually (warning).
Issue: rust-lang/rust#116852
Stabilize keylocker
This PR stabilizes the feature flag `keylocker_x86` (tracking issue rust-lang/rust#134813).
# Public API
The 2 `x86` target features `kl` and `widekl`, and the associated intrinsics in stdarch.
These target features are very specialized, and are only used to signal the presence of the corresponding CPU instruction. They don't have any nontrivial interaction with the ABI (contrary to something like AVX), and serve the only purpose of enabling 11 stdarch intrinsics, all of which have been implemented and propagated to rustc via a stdarch submodule update.
Also, these were added way back in LLVM12, and as the minimum LLVM required for rustc is LLVM19, we are safe in that front too!
# Associated PRs
- rust-lang/rust#134814
- rust-lang/stdarch#1706
- rust-lang/rust#136831 (stdarch submodule update)
- rust-lang/stdarch#1795 (stabilizing the runtime detection and intrinsics)
- rust-lang/rust#141964 (stdarch submodule update for the stabilization of the runtime detection and intrinsics)
As all of the required tasks have been done (adding the target features to rustc, implementing their runtime detection in std_detect and implementing the associated intrinsics in core_arch), these target features can be stabilized now.
cc ````@rust-lang/lang````
cc ````@rust-lang/libs-api```` for the intrinsics and runtime detection
I don't think anyone else worked on this feature, so no one else to ping, maybe cc ````@Amanieu.```` I will send the reference pr soon.
Stabilize `sha512`, `sm3` and `sm4` for x86
This PR stabilizes the feature flag `sha512_sm_x86` (tracking issue rust-lang/rust#126624).
# Public API
The 3 `x86` target features `sha512`, `sm3` and `sm4`, and the associated intrinsics in stdarch.
These target features are very specialized, and are only used to signal the presence of the corresponding CPU instruction. They don't have any nontrivial interaction with the ABI (contrary to something like AVX), and serve the only purpose of enabling 10 stdarch intrinsics, all of which have been implemented and propagated to rustc via a stdarch submodule update.
Also, these were added in LLVM17, and as the minimum LLVM required for rustc is LLVM19, we are safe in that front too!
# Associated PRs
- rust-lang/rust#126704
- rust-lang/stdarch#1592
- rust-lang/stdarch#1790
- rust-lang/rust#140389 (stdarch submodule update)
- rust-lang/stdarch#1796 (stabilizing the runtime detection and intrinsics)
- rust-lang/rust#141964 (stdarch submodule update for the stabilization of the runtime detection and intrinsics)
As all of the required tasks have been done (adding the target features to rustc, implementing their runtime detection in std_detect and implementing the associated intrinsics in core_arch), these target features can be stabilized now.
cc `@rust-lang/lang`
cc `@rust-lang/libs-api` for the intrinsics and runtime detection
I don't think anyone else worked on this feature, so no one else to ping, maybe cc `@Amanieu.` I will send the reference pr soon.
Add (back) `unsupported_calling_conventions` lint to reject more invalid calling conventions
This adds back the `unsupported_calling_conventions` lint that was removed in https://github.com/rust-lang/rust/pull/129935, in order to start the process of dealing with https://github.com/rust-lang/rust/issues/137018. Specifically, we are going for the plan laid out [here](https://github.com/rust-lang/rust/issues/137018#issuecomment-2672118326):
- thiscall, stdcall, fastcall, cdecl should only be accepted on x86-32
- vectorcall should only be accepted on x86-32 and x86-64
The difference to the status quo is that:
- We stop accepting stdcall, fastcall on targets that are windows && non-x86-32 (we already don't accept these on targets that are non-windows && non-x86-32)
- We stop accepting cdecl on targets that are non-x86-32
- (There is no difference for thiscall, this was already a hard error on non-x86-32)
- We stop accepting vectorcall on targets that are windows && non-x86-*
Vectorcall is an unstable ABI so we can just make this a hard error immediately. The others are stable, so we emit the `unsupported_calling_conventions` forward-compat lint. I set up the lint to show up in dependencies via cargo's future-compat report immediately, but we could also make it show up just for the local crate first if that is preferred.
try-job: i686-msvc-1
try-job: x86_64-msvc-1
try-job: test-various
store `target.min_global_align` as an `Align`
Parse the alignment properly when the target is defined/parsed, and error out on invalid alignment values. That means this work doesn't need to happen for every global in each backend.
