From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- compiler/rustc_codegen_llvm/src/abi.rs | 599 +++++++++++++++++++++++++++++++++ 1 file changed, 599 insertions(+) create mode 100644 compiler/rustc_codegen_llvm/src/abi.rs (limited to 'compiler/rustc_codegen_llvm/src/abi.rs') diff --git a/compiler/rustc_codegen_llvm/src/abi.rs b/compiler/rustc_codegen_llvm/src/abi.rs new file mode 100644 index 000000000..9eb3574e7 --- /dev/null +++ b/compiler/rustc_codegen_llvm/src/abi.rs @@ -0,0 +1,599 @@ +use crate::attributes; +use crate::builder::Builder; +use crate::context::CodegenCx; +use crate::llvm::{self, Attribute, AttributePlace}; +use crate::type_::Type; +use crate::type_of::LayoutLlvmExt; +use crate::value::Value; + +use rustc_codegen_ssa::mir::operand::OperandValue; +use rustc_codegen_ssa::mir::place::PlaceRef; +use rustc_codegen_ssa::traits::*; +use rustc_codegen_ssa::MemFlags; +use rustc_middle::bug; +use rustc_middle::ty::layout::LayoutOf; +pub use rustc_middle::ty::layout::{FAT_PTR_ADDR, FAT_PTR_EXTRA}; +use rustc_middle::ty::Ty; +use rustc_session::config; +use rustc_target::abi::call::ArgAbi; +pub use rustc_target::abi::call::*; +use rustc_target::abi::{self, HasDataLayout, Int}; +pub use rustc_target::spec::abi::Abi; + +use libc::c_uint; +use smallvec::SmallVec; + +pub trait ArgAttributesExt { + fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value); + fn apply_attrs_to_callsite( + &self, + idx: AttributePlace, + cx: &CodegenCx<'_, '_>, + callsite: &Value, + ); +} + +fn should_use_mutable_noalias(cx: &CodegenCx<'_, '_>) -> bool { + // LLVM prior to version 12 had known miscompiles in the presence of + // noalias attributes (see #54878), but we don't support earlier + // versions at all anymore. We now enable mutable noalias by default. + cx.tcx.sess.opts.unstable_opts.mutable_noalias.unwrap_or(true) +} + +const ABI_AFFECTING_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 1] = + [(ArgAttribute::InReg, llvm::AttributeKind::InReg)]; + +const OPTIMIZATION_ATTRIBUTES: [(ArgAttribute, llvm::AttributeKind); 5] = [ + (ArgAttribute::NoAlias, llvm::AttributeKind::NoAlias), + (ArgAttribute::NoCapture, llvm::AttributeKind::NoCapture), + (ArgAttribute::NonNull, llvm::AttributeKind::NonNull), + (ArgAttribute::ReadOnly, llvm::AttributeKind::ReadOnly), + (ArgAttribute::NoUndef, llvm::AttributeKind::NoUndef), +]; + +fn get_attrs<'ll>(this: &ArgAttributes, cx: &CodegenCx<'ll, '_>) -> SmallVec<[&'ll Attribute; 8]> { + let mut regular = this.regular; + + let mut attrs = SmallVec::new(); + + // ABI-affecting attributes must always be applied + for (attr, llattr) in ABI_AFFECTING_ATTRIBUTES { + if regular.contains(attr) { + attrs.push(llattr.create_attr(cx.llcx)); + } + } + if let Some(align) = this.pointee_align { + attrs.push(llvm::CreateAlignmentAttr(cx.llcx, align.bytes())); + } + match this.arg_ext { + ArgExtension::None => {} + ArgExtension::Zext => attrs.push(llvm::AttributeKind::ZExt.create_attr(cx.llcx)), + ArgExtension::Sext => attrs.push(llvm::AttributeKind::SExt.create_attr(cx.llcx)), + } + + // Only apply remaining attributes when optimizing + if cx.sess().opts.optimize != config::OptLevel::No { + let deref = this.pointee_size.bytes(); + if deref != 0 { + if regular.contains(ArgAttribute::NonNull) { + attrs.push(llvm::CreateDereferenceableAttr(cx.llcx, deref)); + } else { + attrs.push(llvm::CreateDereferenceableOrNullAttr(cx.llcx, deref)); + } + regular -= ArgAttribute::NonNull; + } + for (attr, llattr) in OPTIMIZATION_ATTRIBUTES { + if regular.contains(attr) { + attrs.push(llattr.create_attr(cx.llcx)); + } + } + if regular.contains(ArgAttribute::NoAliasMutRef) && should_use_mutable_noalias(cx) { + attrs.push(llvm::AttributeKind::NoAlias.create_attr(cx.llcx)); + } + } + + attrs +} + +impl ArgAttributesExt for ArgAttributes { + fn apply_attrs_to_llfn(&self, idx: AttributePlace, cx: &CodegenCx<'_, '_>, llfn: &Value) { + let attrs = get_attrs(self, cx); + attributes::apply_to_llfn(llfn, idx, &attrs); + } + + fn apply_attrs_to_callsite( + &self, + idx: AttributePlace, + cx: &CodegenCx<'_, '_>, + callsite: &Value, + ) { + let attrs = get_attrs(self, cx); + attributes::apply_to_callsite(callsite, idx, &attrs); + } +} + +pub trait LlvmType { + fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type; +} + +impl LlvmType for Reg { + fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type { + match self.kind { + RegKind::Integer => cx.type_ix(self.size.bits()), + RegKind::Float => match self.size.bits() { + 32 => cx.type_f32(), + 64 => cx.type_f64(), + _ => bug!("unsupported float: {:?}", self), + }, + RegKind::Vector => cx.type_vector(cx.type_i8(), self.size.bytes()), + } + } +} + +impl LlvmType for CastTarget { + fn llvm_type<'ll>(&self, cx: &CodegenCx<'ll, '_>) -> &'ll Type { + let rest_ll_unit = self.rest.unit.llvm_type(cx); + let (rest_count, rem_bytes) = if self.rest.unit.size.bytes() == 0 { + (0, 0) + } else { + ( + self.rest.total.bytes() / self.rest.unit.size.bytes(), + self.rest.total.bytes() % self.rest.unit.size.bytes(), + ) + }; + + if self.prefix.iter().all(|x| x.is_none()) { + // Simplify to a single unit when there is no prefix and size <= unit size + if self.rest.total <= self.rest.unit.size { + return rest_ll_unit; + } + + // Simplify to array when all chunks are the same size and type + if rem_bytes == 0 { + return cx.type_array(rest_ll_unit, rest_count); + } + } + + // Create list of fields in the main structure + let mut args: Vec<_> = self + .prefix + .iter() + .flat_map(|option_reg| option_reg.map(|reg| reg.llvm_type(cx))) + .chain((0..rest_count).map(|_| rest_ll_unit)) + .collect(); + + // Append final integer + if rem_bytes != 0 { + // Only integers can be really split further. + assert_eq!(self.rest.unit.kind, RegKind::Integer); + args.push(cx.type_ix(rem_bytes * 8)); + } + + cx.type_struct(&args, false) + } +} + +pub trait ArgAbiExt<'ll, 'tcx> { + fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type; + fn store( + &self, + bx: &mut Builder<'_, 'll, 'tcx>, + val: &'ll Value, + dst: PlaceRef<'tcx, &'ll Value>, + ); + fn store_fn_arg( + &self, + bx: &mut Builder<'_, 'll, 'tcx>, + idx: &mut usize, + dst: PlaceRef<'tcx, &'ll Value>, + ); +} + +impl<'ll, 'tcx> ArgAbiExt<'ll, 'tcx> for ArgAbi<'tcx, Ty<'tcx>> { + /// Gets the LLVM type for a place of the original Rust type of + /// this argument/return, i.e., the result of `type_of::type_of`. + fn memory_ty(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type { + self.layout.llvm_type(cx) + } + + /// Stores a direct/indirect value described by this ArgAbi into a + /// place for the original Rust type of this argument/return. + /// Can be used for both storing formal arguments into Rust variables + /// or results of call/invoke instructions into their destinations. + fn store( + &self, + bx: &mut Builder<'_, 'll, 'tcx>, + val: &'ll Value, + dst: PlaceRef<'tcx, &'ll Value>, + ) { + if self.is_ignore() { + return; + } + if self.is_sized_indirect() { + OperandValue::Ref(val, None, self.layout.align.abi).store(bx, dst) + } else if self.is_unsized_indirect() { + bug!("unsized `ArgAbi` must be handled through `store_fn_arg`"); + } else if let PassMode::Cast(cast) = self.mode { + // FIXME(eddyb): Figure out when the simpler Store is safe, clang + // uses it for i16 -> {i8, i8}, but not for i24 -> {i8, i8, i8}. + let can_store_through_cast_ptr = false; + if can_store_through_cast_ptr { + let cast_ptr_llty = bx.type_ptr_to(cast.llvm_type(bx)); + let cast_dst = bx.pointercast(dst.llval, cast_ptr_llty); + bx.store(val, cast_dst, self.layout.align.abi); + } else { + // The actual return type is a struct, but the ABI + // adaptation code has cast it into some scalar type. The + // code that follows is the only reliable way I have + // found to do a transform like i64 -> {i32,i32}. + // Basically we dump the data onto the stack then memcpy it. + // + // Other approaches I tried: + // - Casting rust ret pointer to the foreign type and using Store + // is (a) unsafe if size of foreign type > size of rust type and + // (b) runs afoul of strict aliasing rules, yielding invalid + // assembly under -O (specifically, the store gets removed). + // - Truncating foreign type to correct integral type and then + // bitcasting to the struct type yields invalid cast errors. + + // We instead thus allocate some scratch space... + let scratch_size = cast.size(bx); + let scratch_align = cast.align(bx); + let llscratch = bx.alloca(cast.llvm_type(bx), scratch_align); + bx.lifetime_start(llscratch, scratch_size); + + // ... where we first store the value... + bx.store(val, llscratch, scratch_align); + + // ... and then memcpy it to the intended destination. + bx.memcpy( + dst.llval, + self.layout.align.abi, + llscratch, + scratch_align, + bx.const_usize(self.layout.size.bytes()), + MemFlags::empty(), + ); + + bx.lifetime_end(llscratch, scratch_size); + } + } else { + OperandValue::Immediate(val).store(bx, dst); + } + } + + fn store_fn_arg( + &self, + bx: &mut Builder<'_, 'll, 'tcx>, + idx: &mut usize, + dst: PlaceRef<'tcx, &'ll Value>, + ) { + let mut next = || { + let val = llvm::get_param(bx.llfn(), *idx as c_uint); + *idx += 1; + val + }; + match self.mode { + PassMode::Ignore => {} + PassMode::Pair(..) => { + OperandValue::Pair(next(), next()).store(bx, dst); + } + PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => { + OperandValue::Ref(next(), Some(next()), self.layout.align.abi).store(bx, dst); + } + PassMode::Direct(_) + | PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } + | PassMode::Cast(_) => { + let next_arg = next(); + self.store(bx, next_arg, dst); + } + } + } +} + +impl<'ll, 'tcx> ArgAbiMethods<'tcx> for Builder<'_, 'll, 'tcx> { + fn store_fn_arg( + &mut self, + arg_abi: &ArgAbi<'tcx, Ty<'tcx>>, + idx: &mut usize, + dst: PlaceRef<'tcx, Self::Value>, + ) { + arg_abi.store_fn_arg(self, idx, dst) + } + fn store_arg( + &mut self, + arg_abi: &ArgAbi<'tcx, Ty<'tcx>>, + val: &'ll Value, + dst: PlaceRef<'tcx, &'ll Value>, + ) { + arg_abi.store(self, val, dst) + } + fn arg_memory_ty(&self, arg_abi: &ArgAbi<'tcx, Ty<'tcx>>) -> &'ll Type { + arg_abi.memory_ty(self) + } +} + +pub trait FnAbiLlvmExt<'ll, 'tcx> { + fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type; + fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type; + fn llvm_cconv(&self) -> llvm::CallConv; + fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value); + fn apply_attrs_callsite(&self, bx: &mut Builder<'_, 'll, 'tcx>, callsite: &'ll Value); +} + +impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> { + fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type { + // Ignore "extra" args from the call site for C variadic functions. + // Only the "fixed" args are part of the LLVM function signature. + let args = if self.c_variadic { &self.args[..self.fixed_count] } else { &self.args }; + + let args_capacity: usize = args.iter().map(|arg| + if arg.pad.is_some() { 1 } else { 0 } + + if let PassMode::Pair(_, _) = arg.mode { 2 } else { 1 } + ).sum(); + let mut llargument_tys = Vec::with_capacity( + if let PassMode::Indirect { .. } = self.ret.mode { 1 } else { 0 } + args_capacity, + ); + + let llreturn_ty = match self.ret.mode { + PassMode::Ignore => cx.type_void(), + PassMode::Direct(_) | PassMode::Pair(..) => self.ret.layout.immediate_llvm_type(cx), + PassMode::Cast(cast) => cast.llvm_type(cx), + PassMode::Indirect { .. } => { + llargument_tys.push(cx.type_ptr_to(self.ret.memory_ty(cx))); + cx.type_void() + } + }; + + for arg in args { + // add padding + if let Some(ty) = arg.pad { + llargument_tys.push(ty.llvm_type(cx)); + } + + let llarg_ty = match arg.mode { + PassMode::Ignore => continue, + PassMode::Direct(_) => arg.layout.immediate_llvm_type(cx), + PassMode::Pair(..) => { + llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 0, true)); + llargument_tys.push(arg.layout.scalar_pair_element_llvm_type(cx, 1, true)); + continue; + } + PassMode::Indirect { attrs: _, extra_attrs: Some(_), on_stack: _ } => { + let ptr_ty = cx.tcx.mk_mut_ptr(arg.layout.ty); + let ptr_layout = cx.layout_of(ptr_ty); + llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 0, true)); + llargument_tys.push(ptr_layout.scalar_pair_element_llvm_type(cx, 1, true)); + continue; + } + PassMode::Cast(cast) => cast.llvm_type(cx), + PassMode::Indirect { attrs: _, extra_attrs: None, on_stack: _ } => { + cx.type_ptr_to(arg.memory_ty(cx)) + } + }; + llargument_tys.push(llarg_ty); + } + + if self.c_variadic { + cx.type_variadic_func(&llargument_tys, llreturn_ty) + } else { + cx.type_func(&llargument_tys, llreturn_ty) + } + } + + fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type { + unsafe { + llvm::LLVMPointerType( + self.llvm_type(cx), + cx.data_layout().instruction_address_space.0 as c_uint, + ) + } + } + + fn llvm_cconv(&self) -> llvm::CallConv { + match self.conv { + Conv::C | Conv::Rust | Conv::CCmseNonSecureCall => llvm::CCallConv, + Conv::RustCold => llvm::ColdCallConv, + Conv::AmdGpuKernel => llvm::AmdGpuKernel, + Conv::AvrInterrupt => llvm::AvrInterrupt, + Conv::AvrNonBlockingInterrupt => llvm::AvrNonBlockingInterrupt, + Conv::ArmAapcs => llvm::ArmAapcsCallConv, + Conv::Msp430Intr => llvm::Msp430Intr, + Conv::PtxKernel => llvm::PtxKernel, + Conv::X86Fastcall => llvm::X86FastcallCallConv, + Conv::X86Intr => llvm::X86_Intr, + Conv::X86Stdcall => llvm::X86StdcallCallConv, + Conv::X86ThisCall => llvm::X86_ThisCall, + Conv::X86VectorCall => llvm::X86_VectorCall, + Conv::X86_64SysV => llvm::X86_64_SysV, + Conv::X86_64Win64 => llvm::X86_64_Win64, + } + } + + fn apply_attrs_llfn(&self, cx: &CodegenCx<'ll, 'tcx>, llfn: &'ll Value) { + let mut func_attrs = SmallVec::<[_; 2]>::new(); + if self.ret.layout.abi.is_uninhabited() { + func_attrs.push(llvm::AttributeKind::NoReturn.create_attr(cx.llcx)); + } + if !self.can_unwind { + func_attrs.push(llvm::AttributeKind::NoUnwind.create_attr(cx.llcx)); + } + attributes::apply_to_llfn(llfn, llvm::AttributePlace::Function, &{ func_attrs }); + + let mut i = 0; + let mut apply = |attrs: &ArgAttributes| { + attrs.apply_attrs_to_llfn(llvm::AttributePlace::Argument(i), cx, llfn); + i += 1; + i - 1 + }; + match self.ret.mode { + PassMode::Direct(ref attrs) => { + attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn); + } + PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => { + assert!(!on_stack); + let i = apply(attrs); + let sret = llvm::CreateStructRetAttr(cx.llcx, self.ret.layout.llvm_type(cx)); + attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[sret]); + } + PassMode::Cast(cast) => { + cast.attrs.apply_attrs_to_llfn(llvm::AttributePlace::ReturnValue, cx, llfn); + } + _ => {} + } + for arg in &self.args { + if arg.pad.is_some() { + apply(&ArgAttributes::new()); + } + match arg.mode { + PassMode::Ignore => {} + PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => { + let i = apply(attrs); + let byval = llvm::CreateByValAttr(cx.llcx, arg.layout.llvm_type(cx)); + attributes::apply_to_llfn(llfn, llvm::AttributePlace::Argument(i), &[byval]); + } + PassMode::Direct(ref attrs) + | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => { + apply(attrs); + } + PassMode::Indirect { ref attrs, extra_attrs: Some(ref extra_attrs), on_stack } => { + assert!(!on_stack); + apply(attrs); + apply(extra_attrs); + } + PassMode::Pair(ref a, ref b) => { + apply(a); + apply(b); + } + PassMode::Cast(cast) => { + apply(&cast.attrs); + } + } + } + } + + fn apply_attrs_callsite(&self, bx: &mut Builder<'_, 'll, 'tcx>, callsite: &'ll Value) { + let mut func_attrs = SmallVec::<[_; 2]>::new(); + if self.ret.layout.abi.is_uninhabited() { + func_attrs.push(llvm::AttributeKind::NoReturn.create_attr(bx.cx.llcx)); + } + if !self.can_unwind { + func_attrs.push(llvm::AttributeKind::NoUnwind.create_attr(bx.cx.llcx)); + } + attributes::apply_to_callsite(callsite, llvm::AttributePlace::Function, &{ func_attrs }); + + let mut i = 0; + let mut apply = |cx: &CodegenCx<'_, '_>, attrs: &ArgAttributes| { + attrs.apply_attrs_to_callsite(llvm::AttributePlace::Argument(i), cx, callsite); + i += 1; + i - 1 + }; + match self.ret.mode { + PassMode::Direct(ref attrs) => { + attrs.apply_attrs_to_callsite(llvm::AttributePlace::ReturnValue, bx.cx, callsite); + } + PassMode::Indirect { ref attrs, extra_attrs: _, on_stack } => { + assert!(!on_stack); + let i = apply(bx.cx, attrs); + let sret = llvm::CreateStructRetAttr(bx.cx.llcx, self.ret.layout.llvm_type(bx)); + attributes::apply_to_callsite(callsite, llvm::AttributePlace::Argument(i), &[sret]); + } + PassMode::Cast(cast) => { + cast.attrs.apply_attrs_to_callsite( + llvm::AttributePlace::ReturnValue, + &bx.cx, + callsite, + ); + } + _ => {} + } + if let abi::Abi::Scalar(scalar) = self.ret.layout.abi { + // If the value is a boolean, the range is 0..2 and that ultimately + // become 0..0 when the type becomes i1, which would be rejected + // by the LLVM verifier. + if let Int(..) = scalar.primitive() { + if !scalar.is_bool() && !scalar.is_always_valid(bx) { + bx.range_metadata(callsite, scalar.valid_range(bx)); + } + } + } + for arg in &self.args { + if arg.pad.is_some() { + apply(bx.cx, &ArgAttributes::new()); + } + match arg.mode { + PassMode::Ignore => {} + PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: true } => { + let i = apply(bx.cx, attrs); + let byval = llvm::CreateByValAttr(bx.cx.llcx, arg.layout.llvm_type(bx)); + attributes::apply_to_callsite( + callsite, + llvm::AttributePlace::Argument(i), + &[byval], + ); + } + PassMode::Direct(ref attrs) + | PassMode::Indirect { ref attrs, extra_attrs: None, on_stack: false } => { + apply(bx.cx, attrs); + } + PassMode::Indirect { + ref attrs, + extra_attrs: Some(ref extra_attrs), + on_stack: _, + } => { + apply(bx.cx, attrs); + apply(bx.cx, extra_attrs); + } + PassMode::Pair(ref a, ref b) => { + apply(bx.cx, a); + apply(bx.cx, b); + } + PassMode::Cast(cast) => { + apply(bx.cx, &cast.attrs); + } + } + } + + let cconv = self.llvm_cconv(); + if cconv != llvm::CCallConv { + llvm::SetInstructionCallConv(callsite, cconv); + } + + if self.conv == Conv::CCmseNonSecureCall { + // This will probably get ignored on all targets but those supporting the TrustZone-M + // extension (thumbv8m targets). + let cmse_nonsecure_call = llvm::CreateAttrString(bx.cx.llcx, "cmse_nonsecure_call"); + attributes::apply_to_callsite( + callsite, + llvm::AttributePlace::Function, + &[cmse_nonsecure_call], + ); + } + + // Some intrinsics require that an elementtype attribute (with the pointee type of a + // pointer argument) is added to the callsite. + let element_type_index = unsafe { llvm::LLVMRustGetElementTypeArgIndex(callsite) }; + if element_type_index >= 0 { + let arg_ty = self.args[element_type_index as usize].layout.ty; + let pointee_ty = arg_ty.builtin_deref(true).expect("Must be pointer argument").ty; + let element_type_attr = unsafe { + llvm::LLVMRustCreateElementTypeAttr(bx.llcx, bx.layout_of(pointee_ty).llvm_type(bx)) + }; + attributes::apply_to_callsite( + callsite, + llvm::AttributePlace::Argument(element_type_index as u32), + &[element_type_attr], + ); + } + } +} + +impl<'tcx> AbiBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> { + fn apply_attrs_callsite(&mut self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>, callsite: Self::Value) { + fn_abi.apply_attrs_callsite(self, callsite) + } + + fn get_param(&mut self, index: usize) -> Self::Value { + llvm::get_param(self.llfn(), index as c_uint) + } +} -- cgit v1.2.3