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Emit error when calling/declaring functions with unavailable vectors.
On some architectures, vector types may have a different ABI when relevant target features are enabled. As discussed in rust-lang/lang-team#235, this turns out to very easily lead to unsound code. This commit makes it an error to declare or call functions using those vector types in a context in which the corresponding target features are disabled, if using an ABI for which the difference is relevant.
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,111 @@ | ||
use rustc_abi::Abi; | ||
use rustc_middle::ty::{self, Instance, InstanceKind, ParamEnv, Ty, TyCtxt}; | ||
use rustc_span::{def_id::DefId, Span, Symbol}; | ||
use rustc_target::abi::call::{FnAbi, PassMode}; | ||
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use crate::errors::{AbiErrorDisabledVectorTypeCall, AbiErrorDisabledVectorTypeDef}; | ||
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const SSE_FEATURES: &'static [&'static str] = &["sse", "sse2", "ssse3", "sse3", "sse4.1", "sse4.2"]; | ||
const AVX_FEATURES: &'static [&'static str] = &["avx", "avx2", "f16c", "fma"]; | ||
const AVX512_FEATURES: &'static [&'static str] = &[ | ||
"avx512f", | ||
"avx512bw", | ||
"avx512cd", | ||
"avx512er", | ||
"avx512pf", | ||
"avx512vl", | ||
"avx512dq", | ||
"avx512ifma", | ||
"avx512vbmi", | ||
"avx512vnni", | ||
"avx512bitalg", | ||
"avx512vpopcntdq", | ||
"avx512bf16", | ||
"avx512vbmi2", | ||
]; | ||
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fn do_check_abi<'tcx>( | ||
tcx: TyCtxt<'tcx>, | ||
abi: &FnAbi<'tcx, Ty<'tcx>>, | ||
target_feature_def: DefId, | ||
emit_err: impl Fn(&'static str), | ||
) { | ||
// FIXME: add support for other architectures | ||
if tcx.sess.target.arch != "x86" && tcx.sess.target.arch != "x86_64" { | ||
return; | ||
} | ||
let codegen_attrs = tcx.codegen_fn_attrs(target_feature_def); | ||
for arg_abi in abi.args.iter().chain(std::iter::once(&abi.ret)) { | ||
let size = arg_abi.layout.size; | ||
if matches!(arg_abi.layout.abi, Abi::Vector { .. }) | ||
&& matches!(arg_abi.mode, PassMode::Direct(_)) | ||
{ | ||
let features: &[_] = match size.bits() { | ||
x if x <= 128 => &[SSE_FEATURES, AVX_FEATURES, AVX512_FEATURES], | ||
x if x <= 256 => &[AVX_FEATURES, AVX512_FEATURES], | ||
x if x <= 512 => &[AVX512_FEATURES], | ||
_ => { | ||
panic!("Unknown vector size for x86: {}; arg = {:?}", size.bits(), arg_abi) | ||
} | ||
}; | ||
let required_feature = features.iter().map(|x| x.iter()).flatten().next().unwrap(); | ||
if !features.iter().map(|x| x.iter()).flatten().any(|feature| { | ||
let required_feature_sym = Symbol::intern(feature); | ||
tcx.sess.unstable_target_features.contains(&required_feature_sym) | ||
|| codegen_attrs.target_features.contains(&required_feature_sym) | ||
}) { | ||
emit_err(required_feature); | ||
} | ||
} | ||
} | ||
} | ||
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/// Checks that the ABI of a given instance of a function does not contain vector-passed arguments | ||
/// or return values for which the corresponding target feature is not enabled. | ||
pub fn check_instance_abi<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) { | ||
let param_env = ParamEnv::reveal_all(); | ||
let Ok(abi) = tcx.fn_abi_of_instance(param_env.and((instance, ty::List::empty()))) else { | ||
// An error will be reported during codegen if we cannot determine the ABI of this | ||
// function. | ||
return; | ||
}; | ||
do_check_abi(tcx, abi, instance.def_id(), |required_feature| { | ||
tcx.dcx().emit_err(AbiErrorDisabledVectorTypeDef { | ||
span: tcx.def_span(instance.def_id()), | ||
required_feature, | ||
}); | ||
}) | ||
} | ||
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/// Checks that a call expression does not try to pass a vector-passed argument which requires a | ||
/// target feature that the caller does not have, as doing so causes UB because of ABI mismatch. | ||
pub fn check_call_site_abi<'tcx>( | ||
tcx: TyCtxt<'tcx>, | ||
ty: Ty<'tcx>, | ||
span: Span, | ||
caller: InstanceKind<'tcx>, | ||
) { | ||
let param_env = ParamEnv::reveal_all(); | ||
let callee_abi = match *ty.kind() { | ||
ty::FnPtr(sig) => tcx.fn_abi_of_fn_ptr(param_env.and((sig, ty::List::empty()))), | ||
ty::FnDef(def_id, args) => { | ||
// Intrinsics are handled separately by the compiler. | ||
if tcx.intrinsic(def_id).is_some() { | ||
return; | ||
} | ||
let instance = ty::Instance::expect_resolve(tcx, param_env, def_id, args, span); | ||
tcx.fn_abi_of_instance(param_env.and((instance, ty::List::empty()))) | ||
} | ||
_ => { | ||
panic!("Invalid function call"); | ||
} | ||
}; | ||
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let Ok(callee_abi) = callee_abi else { | ||
// ABI failed to compute; this will not get through codegen. | ||
return; | ||
}; | ||
do_check_abi(tcx, callee_abi, caller.def_id(), |required_feature| { | ||
tcx.dcx().emit_err(AbiErrorDisabledVectorTypeCall { span, required_feature }); | ||
}) | ||
} |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,55 @@ | ||
//@ only-x86_64 | ||
//@ build-fail | ||
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#![feature(avx512_target_feature)] | ||
#![feature(portable_simd)] | ||
#![allow(improper_ctypes_definitions)] | ||
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use std::arch::x86_64::*; | ||
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unsafe extern "C" fn f(_: __m256) { | ||
//~^ ABI error: this function definition uses a avx vector type, which is not enabled | ||
todo!() | ||
} | ||
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unsafe extern "C" fn g() -> __m256 { | ||
//~^ ABI error: this function definition uses a avx vector type, which is not enabled | ||
todo!() | ||
} | ||
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#[target_feature(enable = "avx")] | ||
unsafe extern "C" fn favx(_: __m256) { | ||
todo!() | ||
} | ||
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#[target_feature(enable = "avx")] | ||
unsafe extern "C" fn gavx() -> __m256 { | ||
todo!() | ||
} | ||
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fn as_f64x8(d: __m512d) -> std::simd::f64x8 { | ||
unsafe { std::mem::transmute(d) } | ||
} | ||
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unsafe fn test() { | ||
let arg = std::mem::transmute([0.0f64; 8]); | ||
as_f64x8(arg); | ||
} | ||
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fn main() { | ||
unsafe { | ||
f(g()); | ||
//~^ ERROR ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
//~| ERROR ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
} | ||
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unsafe { | ||
favx(gavx()); | ||
//~^ ERROR ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
//~| ERROR ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
} | ||
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unsafe { | ||
test(); | ||
} | ||
} |
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Original file line number | Diff line number | Diff line change |
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@@ -0,0 +1,50 @@ | ||
error: ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
--> $DIR/simd-abi-checks.rs:41:11 | ||
| | ||
LL | f(g()); | ||
| ^^^ | ||
| | ||
= help: consider enabling it globally (-C target-feature=+avx) or locally (#[target_feature(enable="avx")]) | ||
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error: ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
--> $DIR/simd-abi-checks.rs:41:9 | ||
| | ||
LL | f(g()); | ||
| ^^^^^^ | ||
| | ||
= help: consider enabling it globally (-C target-feature=+avx) or locally (#[target_feature(enable="avx")]) | ||
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error: ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
--> $DIR/simd-abi-checks.rs:47:14 | ||
| | ||
LL | favx(gavx()); | ||
| ^^^^^^ | ||
| | ||
= help: consider enabling it globally (-C target-feature=+avx) or locally (#[target_feature(enable="avx")]) | ||
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error: ABI error: this function call uses a avx vector type, which is not enabled in the caller | ||
--> $DIR/simd-abi-checks.rs:47:9 | ||
| | ||
LL | favx(gavx()); | ||
| ^^^^^^^^^^^^ | ||
| | ||
= help: consider enabling it globally (-C target-feature=+avx) or locally (#[target_feature(enable="avx")]) | ||
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error: ABI error: this function definition uses a avx vector type, which is not enabled | ||
--> $DIR/simd-abi-checks.rs:15:1 | ||
| | ||
LL | unsafe extern "C" fn g() -> __m256 { | ||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ||
| | ||
= help: consider enabling it globally (-C target-feature=+avx) or locally (#[target_feature(enable="avx")]) | ||
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error: ABI error: this function definition uses a avx vector type, which is not enabled | ||
--> $DIR/simd-abi-checks.rs:10:1 | ||
| | ||
LL | unsafe extern "C" fn f(_: __m256) { | ||
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ||
| | ||
= help: consider enabling it globally (-C target-feature=+avx) or locally (#[target_feature(enable="avx")]) | ||
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error: aborting due to 6 previous errors | ||
|