diff options
Diffstat (limited to 'compiler/rustc_codegen_llvm/src/debuginfo/mod.rs')
| -rw-r--r-- | compiler/rustc_codegen_llvm/src/debuginfo/mod.rs | 614 |
1 files changed, 614 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs new file mode 100644 index 000000000..cf591295b --- /dev/null +++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs @@ -0,0 +1,614 @@ +#![doc = include_str!("doc.md")] + +use rustc_codegen_ssa::mir::debuginfo::VariableKind::*; + +use self::metadata::{file_metadata, type_di_node}; +use self::metadata::{UNKNOWN_COLUMN_NUMBER, UNKNOWN_LINE_NUMBER}; +use self::namespace::mangled_name_of_instance; +use self::utils::{create_DIArray, is_node_local_to_unit, DIB}; + +use crate::abi::FnAbi; +use crate::builder::Builder; +use crate::common::CodegenCx; +use crate::llvm; +use crate::llvm::debuginfo::{ + DIArray, DIBuilder, DIFile, DIFlags, DILexicalBlock, DILocation, DISPFlags, DIScope, DIType, + DIVariable, +}; +use crate::value::Value; + +use rustc_codegen_ssa::debuginfo::type_names; +use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext, VariableKind}; +use rustc_codegen_ssa::traits::*; +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::sync::Lrc; +use rustc_hir::def_id::{DefId, DefIdMap}; +use rustc_index::vec::IndexVec; +use rustc_middle::mir; +use rustc_middle::ty::layout::LayoutOf; +use rustc_middle::ty::subst::{GenericArgKind, SubstsRef}; +use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TypeVisitable}; +use rustc_session::config::{self, DebugInfo}; +use rustc_session::Session; +use rustc_span::symbol::Symbol; +use rustc_span::{self, BytePos, Pos, SourceFile, SourceFileAndLine, SourceFileHash, Span}; +use rustc_target::abi::Size; + +use libc::c_uint; +use smallvec::SmallVec; +use std::cell::OnceCell; +use std::cell::RefCell; +use std::iter; +use tracing::debug; + +mod create_scope_map; +pub mod gdb; +pub mod metadata; +mod namespace; +mod utils; + +pub use self::create_scope_map::compute_mir_scopes; +pub use self::metadata::build_global_var_di_node; +pub use self::metadata::extend_scope_to_file; + +#[allow(non_upper_case_globals)] +const DW_TAG_auto_variable: c_uint = 0x100; +#[allow(non_upper_case_globals)] +const DW_TAG_arg_variable: c_uint = 0x101; + +/// A context object for maintaining all state needed by the debuginfo module. +pub struct CodegenUnitDebugContext<'ll, 'tcx> { + llcontext: &'ll llvm::Context, + llmod: &'ll llvm::Module, + builder: &'ll mut DIBuilder<'ll>, + created_files: RefCell<FxHashMap<Option<(u128, SourceFileHash)>, &'ll DIFile>>, + + type_map: metadata::TypeMap<'ll, 'tcx>, + namespace_map: RefCell<DefIdMap<&'ll DIScope>>, + recursion_marker_type: OnceCell<&'ll DIType>, +} + +impl Drop for CodegenUnitDebugContext<'_, '_> { + fn drop(&mut self) { + unsafe { + llvm::LLVMRustDIBuilderDispose(&mut *(self.builder as *mut _)); + } + } +} + +impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> { + pub fn new(llmod: &'ll llvm::Module) -> Self { + debug!("CodegenUnitDebugContext::new"); + let builder = unsafe { llvm::LLVMRustDIBuilderCreate(llmod) }; + // DIBuilder inherits context from the module, so we'd better use the same one + let llcontext = unsafe { llvm::LLVMGetModuleContext(llmod) }; + CodegenUnitDebugContext { + llcontext, + llmod, + builder, + created_files: Default::default(), + type_map: Default::default(), + namespace_map: RefCell::new(Default::default()), + recursion_marker_type: OnceCell::new(), + } + } + + pub fn finalize(&self, sess: &Session) { + unsafe { + llvm::LLVMRustDIBuilderFinalize(self.builder); + + if !sess.target.is_like_msvc { + // Debuginfo generation in LLVM by default uses a higher + // version of dwarf than macOS currently understands. We can + // instruct LLVM to emit an older version of dwarf, however, + // for macOS to understand. For more info see #11352 + // This can be overridden using --llvm-opts -dwarf-version,N. + // Android has the same issue (#22398) + let dwarf_version = sess + .opts + .unstable_opts + .dwarf_version + .unwrap_or(sess.target.default_dwarf_version); + llvm::LLVMRustAddModuleFlag( + self.llmod, + llvm::LLVMModFlagBehavior::Warning, + "Dwarf Version\0".as_ptr().cast(), + dwarf_version, + ); + } else { + // Indicate that we want CodeView debug information on MSVC + llvm::LLVMRustAddModuleFlag( + self.llmod, + llvm::LLVMModFlagBehavior::Warning, + "CodeView\0".as_ptr().cast(), + 1, + ) + } + + // Prevent bitcode readers from deleting the debug info. + let ptr = "Debug Info Version\0".as_ptr(); + llvm::LLVMRustAddModuleFlag( + self.llmod, + llvm::LLVMModFlagBehavior::Warning, + ptr.cast(), + llvm::LLVMRustDebugMetadataVersion(), + ); + } + } +} + +/// Creates any deferred debug metadata nodes +pub fn finalize(cx: &CodegenCx<'_, '_>) { + if let Some(dbg_cx) = &cx.dbg_cx { + debug!("finalize"); + + if gdb::needs_gdb_debug_scripts_section(cx) { + // Add a .debug_gdb_scripts section to this compile-unit. This will + // cause GDB to try and load the gdb_load_rust_pretty_printers.py file, + // which activates the Rust pretty printers for binary this section is + // contained in. + gdb::get_or_insert_gdb_debug_scripts_section_global(cx); + } + + dbg_cx.finalize(cx.sess()); + } +} + +impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> { + // FIXME(eddyb) find a common convention for all of the debuginfo-related + // names (choose between `dbg`, `debug`, `debuginfo`, `debug_info` etc.). + fn dbg_var_addr( + &mut self, + dbg_var: &'ll DIVariable, + dbg_loc: &'ll DILocation, + variable_alloca: Self::Value, + direct_offset: Size, + indirect_offsets: &[Size], + ) { + // Convert the direct and indirect offsets to address ops. + // FIXME(eddyb) use `const`s instead of getting the values via FFI, + // the values should match the ones in the DWARF standard anyway. + let op_deref = || unsafe { llvm::LLVMRustDIBuilderCreateOpDeref() }; + let op_plus_uconst = || unsafe { llvm::LLVMRustDIBuilderCreateOpPlusUconst() }; + let mut addr_ops = SmallVec::<[u64; 8]>::new(); + + if direct_offset.bytes() > 0 { + addr_ops.push(op_plus_uconst()); + addr_ops.push(direct_offset.bytes() as u64); + } + for &offset in indirect_offsets { + addr_ops.push(op_deref()); + if offset.bytes() > 0 { + addr_ops.push(op_plus_uconst()); + addr_ops.push(offset.bytes() as u64); + } + } + + unsafe { + // FIXME(eddyb) replace `llvm.dbg.declare` with `llvm.dbg.addr`. + llvm::LLVMRustDIBuilderInsertDeclareAtEnd( + DIB(self.cx()), + variable_alloca, + dbg_var, + addr_ops.as_ptr(), + addr_ops.len() as c_uint, + dbg_loc, + self.llbb(), + ); + } + } + + fn set_dbg_loc(&mut self, dbg_loc: &'ll DILocation) { + unsafe { + let dbg_loc_as_llval = llvm::LLVMRustMetadataAsValue(self.cx().llcx, dbg_loc); + llvm::LLVMSetCurrentDebugLocation(self.llbuilder, dbg_loc_as_llval); + } + } + + fn insert_reference_to_gdb_debug_scripts_section_global(&mut self) { + gdb::insert_reference_to_gdb_debug_scripts_section_global(self) + } + + fn set_var_name(&mut self, value: &'ll Value, name: &str) { + // Avoid wasting time if LLVM value names aren't even enabled. + if self.sess().fewer_names() { + return; + } + + // Only function parameters and instructions are local to a function, + // don't change the name of anything else (e.g. globals). + let param_or_inst = unsafe { + llvm::LLVMIsAArgument(value).is_some() || llvm::LLVMIsAInstruction(value).is_some() + }; + if !param_or_inst { + return; + } + + // Avoid replacing the name if it already exists. + // While we could combine the names somehow, it'd + // get noisy quick, and the usefulness is dubious. + if llvm::get_value_name(value).is_empty() { + llvm::set_value_name(value, name.as_bytes()); + } + } +} + +/// A source code location used to generate debug information. +// FIXME(eddyb) rename this to better indicate it's a duplicate of +// `rustc_span::Loc` rather than `DILocation`, perhaps by making +// `lookup_char_pos` return the right information instead. +pub struct DebugLoc { + /// Information about the original source file. + pub file: Lrc<SourceFile>, + /// The (1-based) line number. + pub line: u32, + /// The (1-based) column number. + pub col: u32, +} + +impl CodegenCx<'_, '_> { + /// Looks up debug source information about a `BytePos`. + // FIXME(eddyb) rename this to better indicate it's a duplicate of + // `lookup_char_pos` rather than `dbg_loc`, perhaps by making + // `lookup_char_pos` return the right information instead. + pub fn lookup_debug_loc(&self, pos: BytePos) -> DebugLoc { + let (file, line, col) = match self.sess().source_map().lookup_line(pos) { + Ok(SourceFileAndLine { sf: file, line }) => { + let line_pos = file.line_begin_pos(pos); + + // Use 1-based indexing. + let line = (line + 1) as u32; + let col = (pos - line_pos).to_u32() + 1; + + (file, line, col) + } + Err(file) => (file, UNKNOWN_LINE_NUMBER, UNKNOWN_COLUMN_NUMBER), + }; + + // For MSVC, omit the column number. + // Otherwise, emit it. This mimics clang behaviour. + // See discussion in https://github.com/rust-lang/rust/issues/42921 + if self.sess().target.is_like_msvc { + DebugLoc { file, line, col: UNKNOWN_COLUMN_NUMBER } + } else { + DebugLoc { file, line, col } + } + } +} + +impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> { + fn create_function_debug_context( + &self, + instance: Instance<'tcx>, + fn_abi: &FnAbi<'tcx, Ty<'tcx>>, + llfn: &'ll Value, + mir: &mir::Body<'tcx>, + ) -> Option<FunctionDebugContext<&'ll DIScope, &'ll DILocation>> { + if self.sess().opts.debuginfo == DebugInfo::None { + return None; + } + + // Initialize fn debug context (including scopes). + let empty_scope = DebugScope { + dbg_scope: self.dbg_scope_fn(instance, fn_abi, Some(llfn)), + inlined_at: None, + file_start_pos: BytePos(0), + file_end_pos: BytePos(0), + }; + let mut fn_debug_context = + FunctionDebugContext { scopes: IndexVec::from_elem(empty_scope, &mir.source_scopes) }; + + // Fill in all the scopes, with the information from the MIR body. + compute_mir_scopes(self, instance, mir, &mut fn_debug_context); + + Some(fn_debug_context) + } + + fn dbg_scope_fn( + &self, + instance: Instance<'tcx>, + fn_abi: &FnAbi<'tcx, Ty<'tcx>>, + maybe_definition_llfn: Option<&'ll Value>, + ) -> &'ll DIScope { + let tcx = self.tcx; + + let def_id = instance.def_id(); + let containing_scope = get_containing_scope(self, instance); + let span = tcx.def_span(def_id); + let loc = self.lookup_debug_loc(span.lo()); + let file_metadata = file_metadata(self, &loc.file); + + let function_type_metadata = unsafe { + let fn_signature = get_function_signature(self, fn_abi); + llvm::LLVMRustDIBuilderCreateSubroutineType(DIB(self), fn_signature) + }; + + let mut name = String::new(); + type_names::push_item_name(tcx, def_id, false, &mut name); + + // Find the enclosing function, in case this is a closure. + let enclosing_fn_def_id = tcx.typeck_root_def_id(def_id); + + // We look up the generics of the enclosing function and truncate the substs + // to their length in order to cut off extra stuff that might be in there for + // closures or generators. + let generics = tcx.generics_of(enclosing_fn_def_id); + let substs = instance.substs.truncate_to(tcx, generics); + + type_names::push_generic_params( + tcx, + tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), substs), + &mut name, + ); + + let template_parameters = get_template_parameters(self, generics, substs); + + let linkage_name = &mangled_name_of_instance(self, instance).name; + // Omit the linkage_name if it is the same as subprogram name. + let linkage_name = if &name == linkage_name { "" } else { linkage_name }; + + // FIXME(eddyb) does this need to be separate from `loc.line` for some reason? + let scope_line = loc.line; + + let mut flags = DIFlags::FlagPrototyped; + + if fn_abi.ret.layout.abi.is_uninhabited() { + flags |= DIFlags::FlagNoReturn; + } + + let mut spflags = DISPFlags::SPFlagDefinition; + if is_node_local_to_unit(self, def_id) { + spflags |= DISPFlags::SPFlagLocalToUnit; + } + if self.sess().opts.optimize != config::OptLevel::No { + spflags |= DISPFlags::SPFlagOptimized; + } + if let Some((id, _)) = tcx.entry_fn(()) { + if id == def_id { + spflags |= DISPFlags::SPFlagMainSubprogram; + } + } + + unsafe { + return llvm::LLVMRustDIBuilderCreateFunction( + DIB(self), + containing_scope, + name.as_ptr().cast(), + name.len(), + linkage_name.as_ptr().cast(), + linkage_name.len(), + file_metadata, + loc.line, + function_type_metadata, + scope_line, + flags, + spflags, + maybe_definition_llfn, + template_parameters, + None, + ); + } + + fn get_function_signature<'ll, 'tcx>( + cx: &CodegenCx<'ll, 'tcx>, + fn_abi: &FnAbi<'tcx, Ty<'tcx>>, + ) -> &'ll DIArray { + if cx.sess().opts.debuginfo == DebugInfo::Limited { + return create_DIArray(DIB(cx), &[]); + } + + let mut signature = Vec::with_capacity(fn_abi.args.len() + 1); + + // Return type -- llvm::DIBuilder wants this at index 0 + signature.push(if fn_abi.ret.is_ignore() { + None + } else { + Some(type_di_node(cx, fn_abi.ret.layout.ty)) + }); + + // Arguments types + if cx.sess().target.is_like_msvc { + // FIXME(#42800): + // There is a bug in MSDIA that leads to a crash when it encounters + // a fixed-size array of `u8` or something zero-sized in a + // function-type (see #40477). + // As a workaround, we replace those fixed-size arrays with a + // pointer-type. So a function `fn foo(a: u8, b: [u8; 4])` would + // appear as `fn foo(a: u8, b: *const u8)` in debuginfo, + // and a function `fn bar(x: [(); 7])` as `fn bar(x: *const ())`. + // This transformed type is wrong, but these function types are + // already inaccurate due to ABI adjustments (see #42800). + signature.extend(fn_abi.args.iter().map(|arg| { + let t = arg.layout.ty; + let t = match t.kind() { + ty::Array(ct, _) + if (*ct == cx.tcx.types.u8) || cx.layout_of(*ct).is_zst() => + { + cx.tcx.mk_imm_ptr(*ct) + } + _ => t, + }; + Some(type_di_node(cx, t)) + })); + } else { + signature + .extend(fn_abi.args.iter().map(|arg| Some(type_di_node(cx, arg.layout.ty)))); + } + + create_DIArray(DIB(cx), &signature[..]) + } + + fn get_template_parameters<'ll, 'tcx>( + cx: &CodegenCx<'ll, 'tcx>, + generics: &ty::Generics, + substs: SubstsRef<'tcx>, + ) -> &'ll DIArray { + if substs.types().next().is_none() { + return create_DIArray(DIB(cx), &[]); + } + + // Again, only create type information if full debuginfo is enabled + let template_params: Vec<_> = if cx.sess().opts.debuginfo == DebugInfo::Full { + let names = get_parameter_names(cx, generics); + iter::zip(substs, names) + .filter_map(|(kind, name)| { + if let GenericArgKind::Type(ty) = kind.unpack() { + let actual_type = + cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), ty); + let actual_type_metadata = type_di_node(cx, actual_type); + let name = name.as_str(); + Some(unsafe { + Some(llvm::LLVMRustDIBuilderCreateTemplateTypeParameter( + DIB(cx), + None, + name.as_ptr().cast(), + name.len(), + actual_type_metadata, + )) + }) + } else { + None + } + }) + .collect() + } else { + vec![] + }; + + create_DIArray(DIB(cx), &template_params) + } + + fn get_parameter_names(cx: &CodegenCx<'_, '_>, generics: &ty::Generics) -> Vec<Symbol> { + let mut names = generics.parent.map_or_else(Vec::new, |def_id| { + get_parameter_names(cx, cx.tcx.generics_of(def_id)) + }); + names.extend(generics.params.iter().map(|param| param.name)); + names + } + + fn get_containing_scope<'ll, 'tcx>( + cx: &CodegenCx<'ll, 'tcx>, + instance: Instance<'tcx>, + ) -> &'ll DIScope { + // First, let's see if this is a method within an inherent impl. Because + // if yes, we want to make the result subroutine DIE a child of the + // subroutine's self-type. + let self_type = cx.tcx.impl_of_method(instance.def_id()).and_then(|impl_def_id| { + // If the method does *not* belong to a trait, proceed + if cx.tcx.trait_id_of_impl(impl_def_id).is_none() { + let impl_self_ty = cx.tcx.subst_and_normalize_erasing_regions( + instance.substs, + ty::ParamEnv::reveal_all(), + cx.tcx.type_of(impl_def_id), + ); + + // Only "class" methods are generally understood by LLVM, + // so avoid methods on other types (e.g., `<*mut T>::null`). + match impl_self_ty.kind() { + ty::Adt(def, ..) if !def.is_box() => { + // Again, only create type information if full debuginfo is enabled + if cx.sess().opts.debuginfo == DebugInfo::Full + && !impl_self_ty.needs_subst() + { + Some(type_di_node(cx, impl_self_ty)) + } else { + Some(namespace::item_namespace(cx, def.did())) + } + } + _ => None, + } + } else { + // For trait method impls we still use the "parallel namespace" + // strategy + None + } + }); + + self_type.unwrap_or_else(|| { + namespace::item_namespace( + cx, + DefId { + krate: instance.def_id().krate, + index: cx + .tcx + .def_key(instance.def_id()) + .parent + .expect("get_containing_scope: missing parent?"), + }, + ) + }) + } + } + + fn dbg_loc( + &self, + scope: &'ll DIScope, + inlined_at: Option<&'ll DILocation>, + span: Span, + ) -> &'ll DILocation { + let DebugLoc { line, col, .. } = self.lookup_debug_loc(span.lo()); + + unsafe { llvm::LLVMRustDIBuilderCreateDebugLocation(line, col, scope, inlined_at) } + } + + fn create_vtable_debuginfo( + &self, + ty: Ty<'tcx>, + trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>, + vtable: Self::Value, + ) { + metadata::create_vtable_di_node(self, ty, trait_ref, vtable) + } + + fn extend_scope_to_file( + &self, + scope_metadata: &'ll DIScope, + file: &rustc_span::SourceFile, + ) -> &'ll DILexicalBlock { + metadata::extend_scope_to_file(self, scope_metadata, file) + } + + fn debuginfo_finalize(&self) { + finalize(self) + } + + // FIXME(eddyb) find a common convention for all of the debuginfo-related + // names (choose between `dbg`, `debug`, `debuginfo`, `debug_info` etc.). + fn create_dbg_var( + &self, + variable_name: Symbol, + variable_type: Ty<'tcx>, + scope_metadata: &'ll DIScope, + variable_kind: VariableKind, + span: Span, + ) -> &'ll DIVariable { + let loc = self.lookup_debug_loc(span.lo()); + let file_metadata = file_metadata(self, &loc.file); + + let type_metadata = type_di_node(self, variable_type); + + let (argument_index, dwarf_tag) = match variable_kind { + ArgumentVariable(index) => (index as c_uint, DW_TAG_arg_variable), + LocalVariable => (0, DW_TAG_auto_variable), + }; + let align = self.align_of(variable_type); + + let name = variable_name.as_str(); + unsafe { + llvm::LLVMRustDIBuilderCreateVariable( + DIB(self), + dwarf_tag, + scope_metadata, + name.as_ptr().cast(), + name.len(), + file_metadata, + loc.line, + type_metadata, + true, + DIFlags::FlagZero, + argument_index, + align.bytes() as u32, + ) + } + } +} |