diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/back/write.rs | 21 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/codegen_attrs.rs | 11 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/mod.rs | 6 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/naked_asm.rs | 266 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mono_item.rs | 9 | ||||
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/traits/asm.rs | 7 |
6 files changed, 302 insertions, 18 deletions
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs index 90d48d6ee7e..501f7517919 100644 --- a/compiler/rustc_codegen_ssa/src/back/write.rs +++ b/compiler/rustc_codegen_ssa/src/back/write.rs @@ -34,7 +34,7 @@ use rustc_session::config::{ }; use rustc_span::source_map::SourceMap; use rustc_span::symbol::sym; -use rustc_span::{BytePos, FileName, InnerSpan, Pos, Span}; +use rustc_span::{FileName, InnerSpan, Span, SpanData}; use rustc_target::spec::{MergeFunctions, SanitizerSet}; use tracing::debug; @@ -1837,7 +1837,7 @@ fn spawn_work<'a, B: ExtraBackendMethods>( enum SharedEmitterMessage { Diagnostic(Diagnostic), - InlineAsmError(u32, String, Level, Option<(String, Vec<InnerSpan>)>), + InlineAsmError(SpanData, String, Level, Option<(String, Vec<InnerSpan>)>), Fatal(String), } @@ -1859,12 +1859,12 @@ impl SharedEmitter { pub fn inline_asm_error( &self, - cookie: u32, + span: SpanData, msg: String, level: Level, source: Option<(String, Vec<InnerSpan>)>, ) { - drop(self.sender.send(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source))); + drop(self.sender.send(SharedEmitterMessage::InlineAsmError(span, msg, level, source))); } fn fatal(&self, msg: &str) { @@ -1953,17 +1953,12 @@ impl SharedEmitterMain { dcx.emit_diagnostic(d); sess.dcx().abort_if_errors(); } - Ok(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)) => { + Ok(SharedEmitterMessage::InlineAsmError(span, msg, level, source)) => { assert_matches!(level, Level::Error | Level::Warning | Level::Note); - let msg = msg.strip_prefix("error: ").unwrap_or(&msg).to_string(); let mut err = Diag::<()>::new(sess.dcx(), level, msg); - - // If the cookie is 0 then we don't have span information. - if cookie != 0 { - let pos = BytePos::from_u32(cookie); - let span = Span::with_root_ctxt(pos, pos); - err.span(span); - }; + if !span.is_dummy() { + err.span(span.span()); + } // Point to the generated assembly if it is available. if let Some((buffer, spans)) = source { diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs index 11744eabab0..ab2d24e8d2d 100644 --- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs +++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs @@ -550,6 +550,13 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs { } }); + // naked function MUST NOT be inlined! This attribute is required for the rust compiler itself, + // but not for the code generation backend because at that point the naked function will just be + // a declaration, with a definition provided in global assembly. + if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) { + codegen_fn_attrs.inline = InlineAttr::Never; + } + codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| { if !attr.has_name(sym::optimize) { return ia; @@ -634,10 +641,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs { } } - if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) { - codegen_fn_attrs.inline = InlineAttr::Never; - } - // Weak lang items have the same semantics as "std internal" symbols in the // sense that they're preserved through all our LTO passes and only // strippable by the linker. diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs index 0cbc5c45736..62f69af3f2f 100644 --- a/compiler/rustc_codegen_ssa/src/mir/mod.rs +++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs @@ -20,6 +20,7 @@ mod coverageinfo; pub mod debuginfo; mod intrinsic; mod locals; +mod naked_asm; pub mod operand; pub mod place; mod rvalue; @@ -176,6 +177,11 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( let fn_abi = cx.fn_abi_of_instance(instance, ty::List::empty()); debug!("fn_abi: {:?}", fn_abi); + if cx.tcx().codegen_fn_attrs(instance.def_id()).flags.contains(CodegenFnAttrFlags::NAKED) { + crate::mir::naked_asm::codegen_naked_asm::<Bx>(cx, &mir, instance); + return; + } + let debug_context = cx.create_function_debug_context(instance, fn_abi, llfn, mir); let start_llbb = Bx::append_block(cx, llfn, "start"); diff --git a/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs new file mode 100644 index 00000000000..c08758a9796 --- /dev/null +++ b/compiler/rustc_codegen_ssa/src/mir/naked_asm.rs @@ -0,0 +1,266 @@ +use rustc_attr::InstructionSetAttr; +use rustc_middle::mir::mono::{Linkage, MonoItem, MonoItemData, Visibility}; +use rustc_middle::mir::{Body, InlineAsmOperand}; +use rustc_middle::ty::layout::{HasTyCtxt, HasTypingEnv, LayoutOf}; +use rustc_middle::ty::{Instance, TyCtxt}; +use rustc_middle::{bug, ty}; +use rustc_span::sym; + +use crate::common; +use crate::traits::{AsmCodegenMethods, BuilderMethods, GlobalAsmOperandRef, MiscCodegenMethods}; + +pub(crate) fn codegen_naked_asm<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, + mir: &Body<'tcx>, + instance: Instance<'tcx>, +) { + let rustc_middle::mir::TerminatorKind::InlineAsm { + asm_macro: _, + template, + ref operands, + options, + line_spans, + targets: _, + unwind: _, + } = mir.basic_blocks.iter().next().unwrap().terminator().kind + else { + bug!("#[naked] functions should always terminate with an asm! block") + }; + + let operands: Vec<_> = + operands.iter().map(|op| inline_to_global_operand::<Bx>(cx, instance, op)).collect(); + + let item_data = cx.codegen_unit().items().get(&MonoItem::Fn(instance)).unwrap(); + let name = cx.mangled_name(instance); + let (begin, end) = prefix_and_suffix(cx.tcx(), instance, &name, item_data); + + let mut template_vec = Vec::new(); + template_vec.push(rustc_ast::ast::InlineAsmTemplatePiece::String(begin.into())); + template_vec.extend(template.iter().cloned()); + template_vec.push(rustc_ast::ast::InlineAsmTemplatePiece::String(end.into())); + + cx.codegen_global_asm(&template_vec, &operands, options, line_spans); +} + +fn inline_to_global_operand<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>( + cx: &'a Bx::CodegenCx, + instance: Instance<'tcx>, + op: &InlineAsmOperand<'tcx>, +) -> GlobalAsmOperandRef<'tcx> { + match op { + InlineAsmOperand::Const { value } => { + let const_value = instance + .instantiate_mir_and_normalize_erasing_regions( + cx.tcx(), + cx.typing_env(), + ty::EarlyBinder::bind(value.const_), + ) + .eval(cx.tcx(), cx.typing_env(), value.span) + .expect("erroneous constant missed by mono item collection"); + + let mono_type = instance.instantiate_mir_and_normalize_erasing_regions( + cx.tcx(), + cx.typing_env(), + ty::EarlyBinder::bind(value.ty()), + ); + + let string = common::asm_const_to_str( + cx.tcx(), + value.span, + const_value, + cx.layout_of(mono_type), + ); + + GlobalAsmOperandRef::Const { string } + } + InlineAsmOperand::SymFn { value } => { + let mono_type = instance.instantiate_mir_and_normalize_erasing_regions( + cx.tcx(), + cx.typing_env(), + ty::EarlyBinder::bind(value.ty()), + ); + + let instance = match mono_type.kind() { + &ty::FnDef(def_id, args) => Instance::new(def_id, args), + _ => bug!("asm sym is not a function"), + }; + + GlobalAsmOperandRef::SymFn { instance } + } + InlineAsmOperand::SymStatic { def_id } => { + GlobalAsmOperandRef::SymStatic { def_id: *def_id } + } + InlineAsmOperand::In { .. } + | InlineAsmOperand::Out { .. } + | InlineAsmOperand::InOut { .. } + | InlineAsmOperand::Label { .. } => { + bug!("invalid operand type for naked_asm!") + } + } +} + +enum AsmBinaryFormat { + Elf, + Macho, + Coff, +} + +impl AsmBinaryFormat { + fn from_target(target: &rustc_target::spec::Target) -> Self { + if target.is_like_windows { + Self::Coff + } else if target.is_like_osx { + Self::Macho + } else { + Self::Elf + } + } +} + +fn prefix_and_suffix<'tcx>( + tcx: TyCtxt<'tcx>, + instance: Instance<'tcx>, + asm_name: &str, + item_data: &MonoItemData, +) -> (String, String) { + use std::fmt::Write; + + let asm_binary_format = AsmBinaryFormat::from_target(&tcx.sess.target); + + let is_arm = tcx.sess.target.arch == "arm"; + let is_thumb = tcx.sess.unstable_target_features.contains(&sym::thumb_mode); + + let attrs = tcx.codegen_fn_attrs(instance.def_id()); + let link_section = attrs.link_section.map(|symbol| symbol.as_str().to_string()); + let align = attrs.alignment.map(|a| a.bytes()).unwrap_or(4); + + // See https://sourceware.org/binutils/docs/as/ARM-Directives.html for info on these directives. + // In particular, `.arm` can also be written `.code 32` and `.thumb` as `.code 16`. + let (arch_prefix, arch_suffix) = if is_arm { + ( + match attrs.instruction_set { + None => match is_thumb { + true => ".thumb\n.thumb_func", + false => ".arm", + }, + Some(InstructionSetAttr::ArmT32) => ".thumb\n.thumb_func", + Some(InstructionSetAttr::ArmA32) => ".arm", + }, + match is_thumb { + true => ".thumb", + false => ".arm", + }, + ) + } else { + ("", "") + }; + + let emit_fatal = |msg| tcx.dcx().span_fatal(tcx.def_span(instance.def_id()), msg); + + // see https://godbolt.org/z/cPK4sxKor. + let write_linkage = |w: &mut String| -> std::fmt::Result { + match item_data.linkage { + Linkage::External => { + writeln!(w, ".globl {asm_name}")?; + } + Linkage::LinkOnceAny | Linkage::LinkOnceODR | Linkage::WeakAny | Linkage::WeakODR => { + match asm_binary_format { + AsmBinaryFormat::Elf | AsmBinaryFormat::Coff => { + writeln!(w, ".weak {asm_name}")?; + } + AsmBinaryFormat::Macho => { + writeln!(w, ".globl {asm_name}")?; + writeln!(w, ".weak_definition {asm_name}")?; + } + } + } + Linkage::Internal | Linkage::Private => { + // write nothing + } + Linkage::Appending => emit_fatal("Only global variables can have appending linkage!"), + Linkage::Common => emit_fatal("Functions may not have common linkage"), + Linkage::AvailableExternally => { + // this would make the function equal an extern definition + emit_fatal("Functions may not have available_externally linkage") + } + Linkage::ExternalWeak => { + // FIXME: actually this causes a SIGILL in LLVM + emit_fatal("Functions may not have external weak linkage") + } + } + + Ok(()) + }; + + let mut begin = String::new(); + let mut end = String::new(); + match asm_binary_format { + AsmBinaryFormat::Elf => { + let section = link_section.unwrap_or(format!(".text.{asm_name}")); + + let progbits = match is_arm { + true => "%progbits", + false => "@progbits", + }; + + let function = match is_arm { + true => "%function", + false => "@function", + }; + + writeln!(begin, ".pushsection {section},\"ax\", {progbits}").unwrap(); + writeln!(begin, ".balign {align}").unwrap(); + write_linkage(&mut begin).unwrap(); + if let Visibility::Hidden = item_data.visibility { + writeln!(begin, ".hidden {asm_name}").unwrap(); + } + writeln!(begin, ".type {asm_name}, {function}").unwrap(); + if !arch_prefix.is_empty() { + writeln!(begin, "{}", arch_prefix).unwrap(); + } + writeln!(begin, "{asm_name}:").unwrap(); + + writeln!(end).unwrap(); + writeln!(end, ".size {asm_name}, . - {asm_name}").unwrap(); + writeln!(end, ".popsection").unwrap(); + if !arch_suffix.is_empty() { + writeln!(end, "{}", arch_suffix).unwrap(); + } + } + AsmBinaryFormat::Macho => { + let section = link_section.unwrap_or("__TEXT,__text".to_string()); + writeln!(begin, ".pushsection {},regular,pure_instructions", section).unwrap(); + writeln!(begin, ".balign {align}").unwrap(); + write_linkage(&mut begin).unwrap(); + if let Visibility::Hidden = item_data.visibility { + writeln!(begin, ".private_extern {asm_name}").unwrap(); + } + writeln!(begin, "{asm_name}:").unwrap(); + + writeln!(end).unwrap(); + writeln!(end, ".popsection").unwrap(); + if !arch_suffix.is_empty() { + writeln!(end, "{}", arch_suffix).unwrap(); + } + } + AsmBinaryFormat::Coff => { + let section = link_section.unwrap_or(format!(".text.{asm_name}")); + writeln!(begin, ".pushsection {},\"xr\"", section).unwrap(); + writeln!(begin, ".balign {align}").unwrap(); + write_linkage(&mut begin).unwrap(); + writeln!(begin, ".def {asm_name}").unwrap(); + writeln!(begin, ".scl 2").unwrap(); + writeln!(begin, ".type 32").unwrap(); + writeln!(begin, ".endef {asm_name}").unwrap(); + writeln!(begin, "{asm_name}:").unwrap(); + + writeln!(end).unwrap(); + writeln!(end, ".popsection").unwrap(); + if !arch_suffix.is_empty() { + writeln!(end, "{}", arch_suffix).unwrap(); + } + } + } + + (begin, end) +} diff --git a/compiler/rustc_codegen_ssa/src/mono_item.rs b/compiler/rustc_codegen_ssa/src/mono_item.rs index 038c5857fac..6749bc63327 100644 --- a/compiler/rustc_codegen_ssa/src/mono_item.rs +++ b/compiler/rustc_codegen_ssa/src/mono_item.rs @@ -1,4 +1,5 @@ use rustc_hir as hir; +use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags; use rustc_middle::mir::interpret::ErrorHandled; use rustc_middle::mir::mono::{Linkage, MonoItem, Visibility}; use rustc_middle::ty::Instance; @@ -135,7 +136,13 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> { cx.predefine_static(def_id, linkage, visibility, symbol_name); } MonoItem::Fn(instance) => { - cx.predefine_fn(instance, linkage, visibility, symbol_name); + let attrs = cx.tcx().codegen_fn_attrs(instance.def_id()); + + if attrs.flags.contains(CodegenFnAttrFlags::NAKED) { + // do not define this function; it will become a global assembly block + } else { + cx.predefine_fn(instance, linkage, visibility, symbol_name); + }; } MonoItem::GlobalAsm(..) => {} } diff --git a/compiler/rustc_codegen_ssa/src/traits/asm.rs b/compiler/rustc_codegen_ssa/src/traits/asm.rs index f4853da1156..7767bffbfbf 100644 --- a/compiler/rustc_codegen_ssa/src/traits/asm.rs +++ b/compiler/rustc_codegen_ssa/src/traits/asm.rs @@ -68,4 +68,11 @@ pub trait AsmCodegenMethods<'tcx> { options: InlineAsmOptions, line_spans: &[Span], ); + + /// The mangled name of this instance + /// + /// Additional mangling is used on + /// some targets to add a leading underscore (Mach-O) + /// or byte count suffixes (x86 Windows). + fn mangled_name(&self, instance: Instance<'tcx>) -> String; } |