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Merged
merged 5 commits into from
Jun 26, 2025
Merged

Convert some ABI tests to use extern "rust-invalid" #142992

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586a9d1
tests: split out unsupported-in-impls.rs
workingjubilee Jun 24, 2025
12d05d8
tests: migrate unsupported-abi-transmute.rs to extern "rust-invalid"
workingjubilee Jun 24, 2025
78652b7
tests: specify why extern "rust-invalid" cannot be used in varargs test
workingjubilee Jun 24, 2025
087dabf
Sprinkle breadcrumbs around to lead people to the rust-invalid ABI
workingjubilee Jun 25, 2025
c24914e
compiler: fussily sort the huge AbiMap match
workingjubilee Jun 25, 2025
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19 changes: 13 additions & 6 deletions compiler/rustc_target/src/spec/abi_map.rs
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Expand Up @@ -85,11 +85,16 @@ impl AbiMap {
(ExternAbi::System { .. }, _) => CanonAbi::C,

// fallible lowerings
/* multi-platform */
// always and forever
(ExternAbi::RustInvalid, _) => return AbiMapping::Invalid,

(ExternAbi::EfiApi, Arch::Arm(..)) => CanonAbi::Arm(ArmCall::Aapcs),
(ExternAbi::EfiApi, Arch::X86_64) => CanonAbi::X86(X86Call::Win64),
(ExternAbi::EfiApi, Arch::Aarch64 | Arch::Riscv | Arch::X86) => CanonAbi::C,
(ExternAbi::EfiApi, _) => return AbiMapping::Invalid,

/* arm */
(ExternAbi::Aapcs { .. }, Arch::Arm(..)) => CanonAbi::Arm(ArmCall::Aapcs),
(ExternAbi::Aapcs { .. }, _) => return AbiMapping::Invalid,

Expand All @@ -103,6 +108,12 @@ impl AbiMap {
return AbiMapping::Invalid;
}

/* gpu */
(ExternAbi::PtxKernel, Arch::Nvptx) => CanonAbi::GpuKernel,
(ExternAbi::GpuKernel, Arch::Amdgpu | Arch::Nvptx) => CanonAbi::GpuKernel,
(ExternAbi::PtxKernel | ExternAbi::GpuKernel, _) => return AbiMapping::Invalid,

/* x86 */
(ExternAbi::Cdecl { .. }, Arch::X86) => CanonAbi::C,
(ExternAbi::Cdecl { .. }, _) => return AbiMapping::Deprecated(CanonAbi::C),

Expand Down Expand Up @@ -130,10 +141,7 @@ impl AbiMap {
(ExternAbi::Win64 { .. }, Arch::X86_64) => CanonAbi::X86(X86Call::Win64),
(ExternAbi::SysV64 { .. } | ExternAbi::Win64 { .. }, _) => return AbiMapping::Invalid,

(ExternAbi::PtxKernel, Arch::Nvptx) => CanonAbi::GpuKernel,
(ExternAbi::GpuKernel, Arch::Amdgpu | Arch::Nvptx) => CanonAbi::GpuKernel,
(ExternAbi::PtxKernel | ExternAbi::GpuKernel, _) => return AbiMapping::Invalid,

/* interrupts */
(ExternAbi::AvrInterrupt, Arch::Avr) => CanonAbi::Interrupt(InterruptKind::Avr),
(ExternAbi::AvrNonBlockingInterrupt, Arch::Avr) => {
CanonAbi::Interrupt(InterruptKind::AvrNonBlocking)
Expand All @@ -156,8 +164,7 @@ impl AbiMap {
| ExternAbi::Msp430Interrupt
| ExternAbi::RiscvInterruptM
| ExternAbi::RiscvInterruptS
| ExternAbi::X86Interrupt
| ExternAbi::RustInvalid,
| ExternAbi::X86Interrupt,
_,
) => return AbiMapping::Invalid,
};
Expand Down
5 changes: 5 additions & 0 deletions src/doc/rustc-dev-guide/src/tests/ui.md
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Expand Up @@ -59,6 +59,11 @@ The output is normalized to ignore unwanted differences, see the
[Normalization](#normalization) section. If the file is missing, then
compiletest expects the corresponding output to be empty.

A common reason to use normalization, revisions, and most of the other following tools,
is to account for platform differences. Consider alternatives to these tools, like
e.g. using the `extern "rust-invalid"` ABI that is invalid on every platform
instead of fixing the test to use cross-compilation and testing every possibly-invalid ABI.

There can be multiple stdout/stderr files. The general form is:

```text
Expand Down
2 changes: 2 additions & 0 deletions tests/ui/SUMMARY.md
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Expand Up @@ -8,6 +8,8 @@ For now, only immediate subdirectories under `tests/ui/` are described, but thes

These tests deal with *Application Binary Interfaces* (ABI), mostly relating to function name mangling (and the `#[no_mangle]` attribute), calling conventions, or compiler flags which affect ABI.

Tests for unsupported ABIs can be made cross-platform by using the `extern "rust-invalid"` ABI, which is considered unsupported on every platform.

## `tests/ui/allocator`

These tests exercise `#![feature(allocator_api)]` and the `#[global_allocator]` attribute.
Expand Down
15 changes: 6 additions & 9 deletions tests/ui/abi/unsupported-abi-transmute.rs
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@@ -1,15 +1,12 @@
//@ add-core-stubs
//@ compile-flags: --crate-type=lib --target x86_64-unknown-none
//@ needs-llvm-components: x86
// Check we error before unsupported ABIs reach codegen stages.

//@ edition: 2018
#![no_core]
#![feature(no_core, lang_items)]
extern crate minicore;
use minicore::*;
//@ compile-flags: --crate-type=lib
#![feature(rustc_attrs)]

// Check we error before unsupported ABIs reach codegen stages.
use core::mem;

fn anything() {
let a = unsafe { mem::transmute::<usize, extern "thiscall" fn(i32)>(4) }(2);
let a = unsafe { mem::transmute::<usize, extern "rust-invalid" fn(i32)>(4) }(2);
//~^ ERROR: is not a supported ABI for the current target [E0570]
}
8 changes: 4 additions & 4 deletions tests/ui/abi/unsupported-abi-transmute.stderr
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@@ -1,8 +1,8 @@
error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported-abi-transmute.rs:13:53
error[E0570]: "rust-invalid" is not a supported ABI for the current target
--> $DIR/unsupported-abi-transmute.rs:10:53
|
LL | let a = unsafe { mem::transmute::<usize, extern "thiscall" fn(i32)>(4) }(2);
| ^^^^^^^^^^
LL | let a = unsafe { mem::transmute::<usize, extern "rust-invalid" fn(i32)>(4) }(2);
| ^^^^^^^^^^^^^^

error: aborting due to 1 previous error

Expand Down
36 changes: 36 additions & 0 deletions tests/ui/abi/unsupported-in-impls.rs
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@@ -0,0 +1,36 @@
// Test for https://github.com/rust-lang/rust/issues/86232
// Due to AST-to-HIR lowering nuances, we used to allow unsupported ABIs to "leak" into the HIR
// without being checked, as we would check after generating the ExternAbi.
// Checking afterwards only works if we examine every HIR construct that contains an ExternAbi,
// and those may be very different in HIR, even if they read the same in source.
// This made it very easy to make mistakes.
//
// Here we test that an unsupported ABI in various impl-related positions will be rejected,
// both in the original declarations and the actual implementations.

#![feature(rustc_attrs)]
//@ compile-flags: --crate-type lib

pub struct FnPtrBearer {
pub ptr: extern "rust-invalid" fn(),
//~^ ERROR: is not a supported ABI
}

impl FnPtrBearer {
pub extern "rust-invalid" fn inherent_fn(self) {
//~^ ERROR: is not a supported ABI
(self.ptr)()
}
}

pub trait Trait {
extern "rust-invalid" fn trait_fn(self);
//~^ ERROR: is not a supported ABI
}

impl Trait for FnPtrBearer {
extern "rust-invalid" fn trait_fn(self) {
//~^ ERROR: is not a supported ABI
self.inherent_fn()
}
}
27 changes: 27 additions & 0 deletions tests/ui/abi/unsupported-in-impls.stderr
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@@ -0,0 +1,27 @@
error[E0570]: "rust-invalid" is not a supported ABI for the current target
--> $DIR/unsupported-in-impls.rs:15:21
|
LL | pub ptr: extern "rust-invalid" fn(),
| ^^^^^^^^^^^^^^

error[E0570]: "rust-invalid" is not a supported ABI for the current target
--> $DIR/unsupported-in-impls.rs:20:16
|
LL | pub extern "rust-invalid" fn inherent_fn(self) {
| ^^^^^^^^^^^^^^

error[E0570]: "rust-invalid" is not a supported ABI for the current target
--> $DIR/unsupported-in-impls.rs:27:12
|
LL | extern "rust-invalid" fn trait_fn(self);
| ^^^^^^^^^^^^^^

error[E0570]: "rust-invalid" is not a supported ABI for the current target
--> $DIR/unsupported-in-impls.rs:32:12
|
LL | extern "rust-invalid" fn trait_fn(self) {
| ^^^^^^^^^^^^^^

error: aborting due to 4 previous errors

For more information about this error, try `rustc --explain E0570`.
1 change: 1 addition & 0 deletions tests/ui/abi/unsupported-varargs-fnptr.rs
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@@ -1,5 +1,6 @@
// FIXME(workingjubilee): add revisions and generalize to other platform-specific varargs ABIs,
// preferably after the only-arch directive is enhanced with an "or pattern" syntax
// NOTE: This deliberately tests an ABI that supports varargs, so no `extern "rust-invalid"`
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Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

An alternative would be to, in fact, say "yes, extern "rust-invalid" can support varargs", but that seems silly.

//@ only-x86_64

// We have to use this flag to force ABI computation of an invalid ABI
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/abi/unsupported-varargs-fnptr.stderr
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@@ -1,5 +1,5 @@
error[E0570]: "aapcs" is not a supported ABI for the current target
--> $DIR/unsupported-varargs-fnptr.rs:13:20
--> $DIR/unsupported-varargs-fnptr.rs:14:20
|
LL | fn aapcs(f: extern "aapcs" fn(usize, ...)) {
| ^^^^^^^
Expand Down
26 changes: 1 addition & 25 deletions tests/ui/abi/unsupported.aarch64.stderr
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Expand Up @@ -156,30 +156,6 @@ error[E0570]: "C-cmse-nonsecure-entry" is not a supported ABI for the current ta
LL | extern "C-cmse-nonsecure-entry" {}
| ^^^^^^^^^^^^^^^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:141:17
|
LL | ptr: extern "thiscall" fn(),
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:146:16
|
LL | pub extern "thiscall" fn inherent_fn(self) {
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:153:12
|
LL | extern "thiscall" fn trait_fn(self);
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:158:12
|
LL | extern "thiscall" fn trait_fn(self) {
| ^^^^^^^^^^

warning: "cdecl" is not a supported ABI for the current target
--> $DIR/unsupported.rs:99:17
|
Expand Down Expand Up @@ -221,6 +197,6 @@ LL | extern "cdecl" fn cdecl() {}
= note: for more information, see issue #137018 <https://github.com/rust-lang/rust/issues/137018>
= help: use `extern "C"` instead

error: aborting due to 29 previous errors; 4 warnings emitted
error: aborting due to 25 previous errors; 4 warnings emitted

For more information about this error, try `rustc --explain E0570`.
26 changes: 1 addition & 25 deletions tests/ui/abi/unsupported.arm.stderr
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Expand Up @@ -138,30 +138,6 @@ error[E0570]: "C-cmse-nonsecure-entry" is not a supported ABI for the current ta
LL | extern "C-cmse-nonsecure-entry" {}
| ^^^^^^^^^^^^^^^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:141:17
|
LL | ptr: extern "thiscall" fn(),
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:146:16
|
LL | pub extern "thiscall" fn inherent_fn(self) {
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:153:12
|
LL | extern "thiscall" fn trait_fn(self);
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:158:12
|
LL | extern "thiscall" fn trait_fn(self) {
| ^^^^^^^^^^

warning: "cdecl" is not a supported ABI for the current target
--> $DIR/unsupported.rs:99:17
|
Expand Down Expand Up @@ -203,6 +179,6 @@ LL | extern "cdecl" fn cdecl() {}
= note: for more information, see issue #137018 <https://github.com/rust-lang/rust/issues/137018>
= help: use `extern "C"` instead

error: aborting due to 26 previous errors; 4 warnings emitted
error: aborting due to 22 previous errors; 4 warnings emitted

For more information about this error, try `rustc --explain E0570`.
26 changes: 1 addition & 25 deletions tests/ui/abi/unsupported.riscv32.stderr
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Expand Up @@ -150,30 +150,6 @@ error[E0570]: "C-cmse-nonsecure-entry" is not a supported ABI for the current ta
LL | extern "C-cmse-nonsecure-entry" {}
| ^^^^^^^^^^^^^^^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:141:17
|
LL | ptr: extern "thiscall" fn(),
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:146:16
|
LL | pub extern "thiscall" fn inherent_fn(self) {
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:153:12
|
LL | extern "thiscall" fn trait_fn(self);
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:158:12
|
LL | extern "thiscall" fn trait_fn(self) {
| ^^^^^^^^^^

warning: "cdecl" is not a supported ABI for the current target
--> $DIR/unsupported.rs:99:17
|
Expand Down Expand Up @@ -215,6 +191,6 @@ LL | extern "cdecl" fn cdecl() {}
= note: for more information, see issue #137018 <https://github.com/rust-lang/rust/issues/137018>
= help: use `extern "C"` instead

error: aborting due to 28 previous errors; 4 warnings emitted
error: aborting due to 24 previous errors; 4 warnings emitted

For more information about this error, try `rustc --explain E0570`.
26 changes: 1 addition & 25 deletions tests/ui/abi/unsupported.riscv64.stderr
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Expand Up @@ -150,30 +150,6 @@ error[E0570]: "C-cmse-nonsecure-entry" is not a supported ABI for the current ta
LL | extern "C-cmse-nonsecure-entry" {}
| ^^^^^^^^^^^^^^^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:141:17
|
LL | ptr: extern "thiscall" fn(),
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:146:16
|
LL | pub extern "thiscall" fn inherent_fn(self) {
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:153:12
|
LL | extern "thiscall" fn trait_fn(self);
| ^^^^^^^^^^

error[E0570]: "thiscall" is not a supported ABI for the current target
--> $DIR/unsupported.rs:158:12
|
LL | extern "thiscall" fn trait_fn(self) {
| ^^^^^^^^^^

warning: "cdecl" is not a supported ABI for the current target
--> $DIR/unsupported.rs:99:17
|
Expand Down Expand Up @@ -215,6 +191,6 @@ LL | extern "cdecl" fn cdecl() {}
= note: for more information, see issue #137018 <https://github.com/rust-lang/rust/issues/137018>
= help: use `extern "C"` instead

error: aborting due to 28 previous errors; 4 warnings emitted
error: aborting due to 24 previous errors; 4 warnings emitted

For more information about this error, try `rustc --explain E0570`.
24 changes: 0 additions & 24 deletions tests/ui/abi/unsupported.rs
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Expand Up @@ -136,27 +136,3 @@ extern "C-cmse-nonsecure-entry" {}
extern "cdecl" {}
//[x64_win]~^ WARN unsupported_calling_conventions
//[x64_win]~^^ WARN this was previously accepted

struct FnPtrBearer {
ptr: extern "thiscall" fn(),
//[x64,x64_win,arm,aarch64,riscv32,riscv64]~^ ERROR: is not a supported ABI
}

impl FnPtrBearer {
pub extern "thiscall" fn inherent_fn(self) {
//[x64,x64_win,arm,aarch64,riscv32,riscv64]~^ ERROR: is not a supported ABI
(self.ptr)()
}
}

trait Trait {
extern "thiscall" fn trait_fn(self);
//[x64,x64_win,arm,aarch64,riscv32,riscv64]~^ ERROR: is not a supported ABI
}

impl Trait for FnPtrBearer {
extern "thiscall" fn trait_fn(self) {
//[x64,x64_win,arm,aarch64,riscv32,riscv64]~^ ERROR: is not a supported ABI
self.inherent_fn()
}
}
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