use crate::{ImplTraitContext, ImplTraitPosition, ParamMode, ResolverAstLoweringExt}; use super::errors::{ AbiSpecifiedMultipleTimes, AttSyntaxOnlyX86, ClobberAbiNotSupported, InlineAsmUnsupportedTarget, InvalidAbiClobberAbi, InvalidAsmTemplateModifierConst, InvalidAsmTemplateModifierRegClass, InvalidAsmTemplateModifierRegClassSub, InvalidAsmTemplateModifierSym, InvalidRegister, InvalidRegisterClass, RegisterClassOnlyClobber, RegisterConflict, }; use super::LoweringContext; use rustc_ast::ptr::P; use rustc_ast::*; use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap}; use rustc_hir as hir; use rustc_hir::def::{DefKind, Res}; use rustc_hir::definitions::DefPathData; use rustc_session::parse::feature_err; use rustc_span::{sym, Span}; use rustc_target::asm; use std::collections::hash_map::Entry; use std::fmt::Write; impl<'a, 'hir> LoweringContext<'a, 'hir> { pub(crate) fn lower_inline_asm( &mut self, sp: Span, asm: &InlineAsm, ) -> &'hir hir::InlineAsm<'hir> { // Rustdoc needs to support asm! from foreign architectures: don't try // lowering the register constraints in this case. let asm_arch = if self.tcx.sess.opts.actually_rustdoc { None } else { self.tcx.sess.asm_arch }; if asm_arch.is_none() && !self.tcx.sess.opts.actually_rustdoc { self.tcx.sess.emit_err(InlineAsmUnsupportedTarget { span: sp }); } if let Some(asm_arch) = asm_arch { // Inline assembly is currently only stable for these architectures. let is_stable = matches!( asm_arch, asm::InlineAsmArch::X86 | asm::InlineAsmArch::X86_64 | asm::InlineAsmArch::Arm | asm::InlineAsmArch::AArch64 | asm::InlineAsmArch::RiscV32 | asm::InlineAsmArch::RiscV64 ); if !is_stable && !self.tcx.features().asm_experimental_arch { feature_err( &self.tcx.sess.parse_sess, sym::asm_experimental_arch, sp, "inline assembly is not stable yet on this architecture", ) .emit(); } } if asm.options.contains(InlineAsmOptions::ATT_SYNTAX) && !matches!(asm_arch, Some(asm::InlineAsmArch::X86 | asm::InlineAsmArch::X86_64)) && !self.tcx.sess.opts.actually_rustdoc { self.tcx.sess.emit_err(AttSyntaxOnlyX86 { span: sp }); } if asm.options.contains(InlineAsmOptions::MAY_UNWIND) && !self.tcx.features().asm_unwind { feature_err( &self.tcx.sess.parse_sess, sym::asm_unwind, sp, "the `may_unwind` option is unstable", ) .emit(); } let mut clobber_abis = FxIndexMap::default(); if let Some(asm_arch) = asm_arch { for (abi_name, abi_span) in &asm.clobber_abis { match asm::InlineAsmClobberAbi::parse(asm_arch, &self.tcx.sess.target, *abi_name) { Ok(abi) => { // If the abi was already in the list, emit an error match clobber_abis.get(&abi) { Some((prev_name, prev_sp)) => { // Multiple different abi names may actually be the same ABI // If the specified ABIs are not the same name, alert the user that they resolve to the same ABI let source_map = self.tcx.sess.source_map(); let equivalent = (source_map.span_to_snippet(*prev_sp) != source_map.span_to_snippet(*abi_span)) .then_some(()); self.tcx.sess.emit_err(AbiSpecifiedMultipleTimes { abi_span: *abi_span, prev_name: *prev_name, prev_span: *prev_sp, equivalent, }); } None => { clobber_abis.insert(abi, (*abi_name, *abi_span)); } } } Err(&[]) => { self.tcx.sess.emit_err(ClobberAbiNotSupported { abi_span: *abi_span }); } Err(supported_abis) => { let mut abis = format!("`{}`", supported_abis[0]); for m in &supported_abis[1..] { let _ = write!(abis, ", `{m}`"); } self.tcx.sess.emit_err(InvalidAbiClobberAbi { abi_span: *abi_span, supported_abis: abis, }); } } } } // Lower operands to HIR. We use dummy register classes if an error // occurs during lowering because we still need to be able to produce a // valid HIR. let sess = self.tcx.sess; let mut operands: Vec<_> = asm .operands .iter() .map(|(op, op_sp)| { let lower_reg = |®: &_| match reg { InlineAsmRegOrRegClass::Reg(reg) => { asm::InlineAsmRegOrRegClass::Reg(if let Some(asm_arch) = asm_arch { asm::InlineAsmReg::parse(asm_arch, reg).unwrap_or_else(|error| { sess.emit_err(InvalidRegister { op_span: *op_sp, reg, error }); asm::InlineAsmReg::Err }) } else { asm::InlineAsmReg::Err }) } InlineAsmRegOrRegClass::RegClass(reg_class) => { asm::InlineAsmRegOrRegClass::RegClass(if let Some(asm_arch) = asm_arch { asm::InlineAsmRegClass::parse(asm_arch, reg_class).unwrap_or_else( |error| { sess.emit_err(InvalidRegisterClass { op_span: *op_sp, reg_class, error, }); asm::InlineAsmRegClass::Err }, ) } else { asm::InlineAsmRegClass::Err }) } }; let op = match op { InlineAsmOperand::In { reg, expr } => hir::InlineAsmOperand::In { reg: lower_reg(reg), expr: self.lower_expr(expr), }, InlineAsmOperand::Out { reg, late, expr } => hir::InlineAsmOperand::Out { reg: lower_reg(reg), late: *late, expr: expr.as_ref().map(|expr| self.lower_expr(expr)), }, InlineAsmOperand::InOut { reg, late, expr } => hir::InlineAsmOperand::InOut { reg: lower_reg(reg), late: *late, expr: self.lower_expr(expr), }, InlineAsmOperand::SplitInOut { reg, late, in_expr, out_expr } => { hir::InlineAsmOperand::SplitInOut { reg: lower_reg(reg), late: *late, in_expr: self.lower_expr(in_expr), out_expr: out_expr.as_ref().map(|expr| self.lower_expr(expr)), } } InlineAsmOperand::Const { anon_const } => { if !self.tcx.features().asm_const { feature_err( &sess.parse_sess, sym::asm_const, *op_sp, "const operands for inline assembly are unstable", ) .emit(); } hir::InlineAsmOperand::Const { anon_const: self.lower_anon_const(anon_const), } } InlineAsmOperand::Sym { sym } => { let static_def_id = self .resolver .get_partial_res(sym.id) .and_then(|res| res.full_res()) .and_then(|res| match res { Res::Def(DefKind::Static(_), def_id) => Some(def_id), _ => None, }); if let Some(def_id) = static_def_id { let path = self.lower_qpath( sym.id, &sym.qself, &sym.path, ParamMode::Optional, &ImplTraitContext::Disallowed(ImplTraitPosition::Path), ); hir::InlineAsmOperand::SymStatic { path, def_id } } else { // Replace the InlineAsmSym AST node with an // Expr using the name node id. let expr = Expr { id: sym.id, kind: ExprKind::Path(sym.qself.clone(), sym.path.clone()), span: *op_sp, attrs: AttrVec::new(), tokens: None, }; // Wrap the expression in an AnonConst. let parent_def_id = self.current_hir_id_owner; let node_id = self.next_node_id(); self.create_def( parent_def_id.def_id, node_id, DefPathData::AnonConst, *op_sp, ); let anon_const = AnonConst { id: node_id, value: P(expr) }; hir::InlineAsmOperand::SymFn { anon_const: self.lower_anon_const(&anon_const), } } } }; (op, self.lower_span(*op_sp)) }) .collect(); // Validate template modifiers against the register classes for the operands for p in &asm.template { if let InlineAsmTemplatePiece::Placeholder { operand_idx, modifier: Some(modifier), span: placeholder_span, } = *p { let op_sp = asm.operands[operand_idx].1; match &operands[operand_idx].0 { hir::InlineAsmOperand::In { reg, .. } | hir::InlineAsmOperand::Out { reg, .. } | hir::InlineAsmOperand::InOut { reg, .. } | hir::InlineAsmOperand::SplitInOut { reg, .. } => { let class = reg.reg_class(); if class == asm::InlineAsmRegClass::Err { continue; } let valid_modifiers = class.valid_modifiers(asm_arch.unwrap()); if !valid_modifiers.contains(&modifier) { let sub = if !valid_modifiers.is_empty() { let mut mods = format!("`{}`", valid_modifiers[0]); for m in &valid_modifiers[1..] { let _ = write!(mods, ", `{m}`"); } InvalidAsmTemplateModifierRegClassSub::SupportModifier { class_name: class.name(), modifiers: mods, } } else { InvalidAsmTemplateModifierRegClassSub::DoesNotSupportModifier { class_name: class.name(), } }; sess.emit_err(InvalidAsmTemplateModifierRegClass { placeholder_span, op_span: op_sp, sub, }); } } hir::InlineAsmOperand::Const { .. } => { sess.emit_err(InvalidAsmTemplateModifierConst { placeholder_span, op_span: op_sp, }); } hir::InlineAsmOperand::SymFn { .. } | hir::InlineAsmOperand::SymStatic { .. } => { sess.emit_err(InvalidAsmTemplateModifierSym { placeholder_span, op_span: op_sp, }); } } } } let mut used_input_regs = FxHashMap::default(); let mut used_output_regs = FxHashMap::default(); for (idx, &(ref op, op_sp)) in operands.iter().enumerate() { if let Some(reg) = op.reg() { let reg_class = reg.reg_class(); if reg_class == asm::InlineAsmRegClass::Err { continue; } // Some register classes can only be used as clobbers. This // means that we disallow passing a value in/out of the asm and // require that the operand name an explicit register, not a // register class. if reg_class.is_clobber_only(asm_arch.unwrap()) && !op.is_clobber() { sess.emit_err(RegisterClassOnlyClobber { op_span: op_sp, reg_class_name: reg_class.name(), }); continue; } // Check for conflicts between explicit register operands. if let asm::InlineAsmRegOrRegClass::Reg(reg) = reg { let (input, output) = match op { hir::InlineAsmOperand::In { .. } => (true, false), // Late output do not conflict with inputs, but normal outputs do hir::InlineAsmOperand::Out { late, .. } => (!late, true), hir::InlineAsmOperand::InOut { .. } | hir::InlineAsmOperand::SplitInOut { .. } => (true, true), hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::SymFn { .. } | hir::InlineAsmOperand::SymStatic { .. } => { unreachable!() } }; // Flag to output the error only once per operand let mut skip = false; reg.overlapping_regs(|r| { let mut check = |used_regs: &mut FxHashMap, input| { match used_regs.entry(r) { Entry::Occupied(o) => { if skip { return; } skip = true; let idx2 = *o.get(); let (ref op2, op_sp2) = operands[idx2]; let Some(asm::InlineAsmRegOrRegClass::Reg(reg2)) = op2.reg() else { unreachable!(); }; let in_out = match (op, op2) { ( hir::InlineAsmOperand::In { .. }, hir::InlineAsmOperand::Out { late, .. }, ) | ( hir::InlineAsmOperand::Out { late, .. }, hir::InlineAsmOperand::In { .. }, ) => { assert!(!*late); let out_op_sp = if input { op_sp2 } else { op_sp }; Some(out_op_sp) }, _ => None, }; sess.emit_err(RegisterConflict { op_span1: op_sp, op_span2: op_sp2, reg1_name: reg.name(), reg2_name: reg2.name(), in_out }); } Entry::Vacant(v) => { if r == reg { v.insert(idx); } } } }; if input { check(&mut used_input_regs, true); } if output { check(&mut used_output_regs, false); } }); } } } // If a clobber_abi is specified, add the necessary clobbers to the // operands list. let mut clobbered = FxHashSet::default(); for (abi, (_, abi_span)) in clobber_abis { for &clobber in abi.clobbered_regs() { // Don't emit a clobber for a register already clobbered if clobbered.contains(&clobber) { continue; } let mut output_used = false; clobber.overlapping_regs(|reg| { if used_output_regs.contains_key(®) { output_used = true; } }); if !output_used { operands.push(( hir::InlineAsmOperand::Out { reg: asm::InlineAsmRegOrRegClass::Reg(clobber), late: true, expr: None, }, self.lower_span(abi_span), )); clobbered.insert(clobber); } } } let operands = self.arena.alloc_from_iter(operands); let template = self.arena.alloc_from_iter(asm.template.iter().cloned()); let template_strs = self.arena.alloc_from_iter( asm.template_strs .iter() .map(|(sym, snippet, span)| (*sym, *snippet, self.lower_span(*span))), ); let line_spans = self.arena.alloc_from_iter(asm.line_spans.iter().map(|span| self.lower_span(*span))); let hir_asm = hir::InlineAsm { template, template_strs, operands, options: asm.options, line_spans }; self.arena.alloc(hir_asm) } }