diff options
Diffstat (limited to 'compiler/rustc_target/src/callconv/mod.rs')
| -rw-r--r-- | compiler/rustc_target/src/callconv/mod.rs | 154 |
1 files changed, 82 insertions, 72 deletions
diff --git a/compiler/rustc_target/src/callconv/mod.rs b/compiler/rustc_target/src/callconv/mod.rs index 50ac6c8fcde..1c044fe98b3 100644 --- a/compiler/rustc_target/src/callconv/mod.rs +++ b/compiler/rustc_target/src/callconv/mod.rs @@ -6,9 +6,8 @@ use rustc_abi::{ Size, TyAbiInterface, TyAndLayout, }; use rustc_macros::HashStable_Generic; -use rustc_span::Symbol; -use crate::spec::{HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, WasmCAbi}; +use crate::spec::{HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, RustcAbi, WasmCAbi}; mod aarch64; mod amdgpu; @@ -39,7 +38,7 @@ mod xtensa; pub enum PassMode { /// Ignore the argument. /// - /// The argument is either uninhabited or a ZST. + /// The argument is a ZST. Ignore, /// Pass the argument directly. /// @@ -351,7 +350,6 @@ impl<'a, Ty> ArgAbi<'a, Ty> { scalar_attrs: impl Fn(&TyAndLayout<'a, Ty>, Scalar, Size) -> ArgAttributes, ) -> Self { let mode = match layout.backend_repr { - BackendRepr::Uninhabited => PassMode::Ignore, BackendRepr::Scalar(scalar) => { PassMode::Direct(scalar_attrs(&layout, scalar, Size::ZERO)) } @@ -387,6 +385,7 @@ impl<'a, Ty> ArgAbi<'a, Ty> { /// Pass this argument directly instead. Should NOT be used! /// Only exists because of past ABI mistakes that will take time to fix /// (see <https://github.com/rust-lang/rust/issues/115666>). + #[track_caller] pub fn make_direct_deprecated(&mut self) { match self.mode { PassMode::Indirect { .. } => { @@ -399,6 +398,7 @@ impl<'a, Ty> ArgAbi<'a, Ty> { /// Pass this argument indirectly, by passing a (thin or wide) pointer to the argument instead. /// This is valid for both sized and unsized arguments. + #[track_caller] pub fn make_indirect(&mut self) { match self.mode { PassMode::Direct(_) | PassMode::Pair(_, _) => { @@ -413,6 +413,7 @@ impl<'a, Ty> ArgAbi<'a, Ty> { /// Same as `make_indirect`, but for arguments that are ignored. Only needed for ABIs that pass /// ZSTs indirectly. + #[track_caller] pub fn make_indirect_from_ignore(&mut self) { match self.mode { PassMode::Ignore => { @@ -543,8 +544,6 @@ pub enum Conv { Msp430Intr, - PtxKernel, - GpuKernel, X86Fastcall, @@ -623,19 +622,8 @@ impl<'a, Ty: fmt::Display> fmt::Debug for FnAbi<'a, Ty> { } } -/// Error produced by attempting to adjust a `FnAbi`, for a "foreign" ABI. -#[derive(Copy, Clone, Debug, HashStable_Generic)] -pub enum AdjustForForeignAbiError { - /// Target architecture doesn't support "foreign" (i.e. non-Rust) ABIs. - Unsupported { arch: Symbol, abi: ExternAbi }, -} - impl<'a, Ty> FnAbi<'a, Ty> { - pub fn adjust_for_foreign_abi<C>( - &mut self, - cx: &C, - abi: ExternAbi, - ) -> Result<(), AdjustForForeignAbiError> + pub fn adjust_for_foreign_abi<C>(&mut self, cx: &C, abi: ExternAbi) where Ty: TyAbiInterface<'a, C> + Copy, C: HasDataLayout + HasTargetSpec + HasWasmCAbiOpt + HasX86AbiOpt, @@ -644,7 +632,7 @@ impl<'a, Ty> FnAbi<'a, Ty> { if let Some(arg) = self.args.first_mut() { arg.pass_by_stack_offset(None); } - return Ok(()); + return; } let spec = cx.target_spec(); @@ -701,7 +689,8 @@ impl<'a, Ty> FnAbi<'a, Ty> { "sparc" => sparc::compute_abi_info(cx, self), "sparc64" => sparc64::compute_abi_info(cx, self), "nvptx64" => { - if cx.target_spec().adjust_abi(abi, self.c_variadic) == ExternAbi::PtxKernel { + let abi = cx.target_spec().adjust_abi(abi, self.c_variadic); + if abi == ExternAbi::PtxKernel || abi == ExternAbi::GpuKernel { nvptx64::compute_ptx_kernel_abi_info(cx, self) } else { nvptx64::compute_abi_info(self) @@ -719,15 +708,8 @@ impl<'a, Ty> FnAbi<'a, Ty> { } "wasm64" => wasm::compute_c_abi_info(cx, self), "bpf" => bpf::compute_abi_info(self), - arch => { - return Err(AdjustForForeignAbiError::Unsupported { - arch: Symbol::intern(arch), - abi, - }); - } + arch => panic!("no lowering implemented for {arch}"), } - - Ok(()) } pub fn adjust_for_rust_abi<C>(&mut self, cx: &C, abi: ExternAbi) @@ -736,7 +718,7 @@ impl<'a, Ty> FnAbi<'a, Ty> { C: HasDataLayout + HasTargetSpec, { let spec = cx.target_spec(); - match &spec.arch[..] { + match &*spec.arch { "x86" => x86::compute_rust_abi_info(cx, self, abi), "riscv32" | "riscv64" => riscv::compute_rust_abi_info(cx, self, abi), "loongarch64" => loongarch::compute_rust_abi_info(cx, self, abi), @@ -744,6 +726,24 @@ impl<'a, Ty> FnAbi<'a, Ty> { _ => {} }; + // Decides whether we can pass the given SIMD argument via `PassMode::Direct`. + // May only return `true` if the target will always pass those arguments the same way, + // no matter what the user does with `-Ctarget-feature`! In other words, whatever + // target features are required to pass a SIMD value in registers must be listed in + // the `abi_required_features` for the current target and ABI. + let can_pass_simd_directly = |arg: &ArgAbi<'_, Ty>| match &*spec.arch { + // On x86, if we have SSE2 (which we have by default for x86_64), we can always pass up + // to 128-bit-sized vectors. + "x86" if spec.rustc_abi == Some(RustcAbi::X86Sse2) => arg.layout.size.bits() <= 128, + "x86_64" if spec.rustc_abi != Some(RustcAbi::X86Softfloat) => { + // FIXME once https://github.com/bytecodealliance/wasmtime/issues/10254 is fixed + // accept vectors up to 128bit rather than vectors of exactly 128bit. + arg.layout.size.bits() == 128 + } + // So far, we haven't implemented this logic for any other target. + _ => false, + }; + for (arg_idx, arg) in self .args .iter_mut() @@ -751,12 +751,15 @@ impl<'a, Ty> FnAbi<'a, Ty> { .map(|(idx, arg)| (Some(idx), arg)) .chain(iter::once((None, &mut self.ret))) { - if arg.is_ignore() { + // If the logic above already picked a specific type to cast the argument to, leave that + // in place. + if matches!(arg.mode, PassMode::Ignore | PassMode::Cast { .. }) { continue; } if arg_idx.is_none() && arg.layout.size > Primitive::Pointer(AddressSpace::DATA).size(cx) * 2 + && !matches!(arg.layout.backend_repr, BackendRepr::Vector { .. }) { // Return values larger than 2 registers using a return area // pointer. LLVM and Cranelift disagree about how to return @@ -766,7 +769,8 @@ impl<'a, Ty> FnAbi<'a, Ty> { // return value independently and decide to pass it in a // register or not, which would result in the return value // being passed partially in registers and partially through a - // return area pointer. + // return area pointer. For large IR-level values such as `i128`, + // cranelift will even split up the value into smaller chunks. // // While Cranelift may need to be fixed as the LLVM behavior is // generally more correct with respect to the surface language, @@ -796,53 +800,60 @@ impl<'a, Ty> FnAbi<'a, Ty> { // rustc_target already ensure any return value which doesn't // fit in the available amount of return registers is passed in // the right way for the current target. + // + // The adjustment is not necessary nor desired for types with a vector + // representation; those are handled below. arg.make_indirect(); continue; } match arg.layout.backend_repr { - BackendRepr::Memory { .. } => {} - - // This is a fun case! The gist of what this is doing is - // that we want callers and callees to always agree on the - // ABI of how they pass SIMD arguments. If we were to *not* - // make these arguments indirect then they'd be immediates - // in LLVM, which means that they'd used whatever the - // appropriate ABI is for the callee and the caller. That - // means, for example, if the caller doesn't have AVX - // enabled but the callee does, then passing an AVX argument - // across this boundary would cause corrupt data to show up. - // - // This problem is fixed by unconditionally passing SIMD - // arguments through memory between callers and callees - // which should get them all to agree on ABI regardless of - // target feature sets. Some more information about this - // issue can be found in #44367. - // - // Note that the intrinsic ABI is exempt here as - // that's how we connect up to LLVM and it's unstable - // anyway, we control all calls to it in libstd. - BackendRepr::Vector { .. } - if abi != ExternAbi::RustIntrinsic && spec.simd_types_indirect => - { - arg.make_indirect(); - continue; + BackendRepr::Memory { .. } => { + // Compute `Aggregate` ABI. + + let is_indirect_not_on_stack = + matches!(arg.mode, PassMode::Indirect { on_stack: false, .. }); + assert!(is_indirect_not_on_stack); + + let size = arg.layout.size; + if arg.layout.is_sized() + && size <= Primitive::Pointer(AddressSpace::DATA).size(cx) + { + // We want to pass small aggregates as immediates, but using + // an LLVM aggregate type for this leads to bad optimizations, + // so we pick an appropriately sized integer type instead. + arg.cast_to(Reg { kind: RegKind::Integer, size }); + } } - _ => continue, - } - // Compute `Aggregate` ABI. - - let is_indirect_not_on_stack = - matches!(arg.mode, PassMode::Indirect { on_stack: false, .. }); - assert!(is_indirect_not_on_stack); - - let size = arg.layout.size; - if !arg.layout.is_unsized() && size <= Primitive::Pointer(AddressSpace::DATA).size(cx) { - // We want to pass small aggregates as immediates, but using - // an LLVM aggregate type for this leads to bad optimizations, - // so we pick an appropriately sized integer type instead. - arg.cast_to(Reg { kind: RegKind::Integer, size }); + BackendRepr::Vector { .. } => { + // This is a fun case! The gist of what this is doing is + // that we want callers and callees to always agree on the + // ABI of how they pass SIMD arguments. If we were to *not* + // make these arguments indirect then they'd be immediates + // in LLVM, which means that they'd used whatever the + // appropriate ABI is for the callee and the caller. That + // means, for example, if the caller doesn't have AVX + // enabled but the callee does, then passing an AVX argument + // across this boundary would cause corrupt data to show up. + // + // This problem is fixed by unconditionally passing SIMD + // arguments through memory between callers and callees + // which should get them all to agree on ABI regardless of + // target feature sets. Some more information about this + // issue can be found in #44367. + // + // Note that the intrinsic ABI is exempt here as those are not + // real functions anyway, and the backend expects very specific types. + if abi != ExternAbi::RustIntrinsic + && spec.simd_types_indirect + && !can_pass_simd_directly(arg) + { + arg.make_indirect(); + } + } + + _ => {} } } } @@ -860,7 +871,6 @@ impl FromStr for Conv { "CCmseNonSecureCall" => Ok(Conv::CCmseNonSecureCall), "CCmseNonSecureEntry" => Ok(Conv::CCmseNonSecureEntry), "Msp430Intr" => Ok(Conv::Msp430Intr), - "PtxKernel" => Ok(Conv::PtxKernel), "X86Fastcall" => Ok(Conv::X86Fastcall), "X86Intr" => Ok(Conv::X86Intr), "X86Stdcall" => Ok(Conv::X86Stdcall), |