1 #![doc = include_str!("doc.md")]
3 use rustc_codegen_ssa::mir::debuginfo::VariableKind::*;
5 use self::metadata::{file_metadata, type_metadata, TypeMap};
6 use self::metadata::{UNKNOWN_COLUMN_NUMBER, UNKNOWN_LINE_NUMBER};
7 use self::namespace::mangled_name_of_instance;
8 use self::utils::{create_DIArray, is_node_local_to_unit, DIB};
10 use crate::abi::FnAbi;
11 use crate::builder::Builder;
12 use crate::common::CodegenCx;
14 use crate::llvm::debuginfo::{
15 DIArray, DIBuilder, DIFile, DIFlags, DILexicalBlock, DILocation, DISPFlags, DIScope, DIType,
18 use crate::value::Value;
20 use rustc_codegen_ssa::debuginfo::type_names;
21 use rustc_codegen_ssa::mir::debuginfo::{DebugScope, FunctionDebugContext, VariableKind};
22 use rustc_codegen_ssa::traits::*;
23 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
24 use rustc_data_structures::sync::Lrc;
25 use rustc_hir::def_id::{DefId, DefIdMap};
26 use rustc_index::vec::IndexVec;
27 use rustc_middle::mir;
28 use rustc_middle::ty::layout::LayoutOf;
29 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
30 use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TypeFoldable};
31 use rustc_session::config::{self, DebugInfo};
32 use rustc_session::Session;
33 use rustc_span::symbol::Symbol;
34 use rustc_span::{self, BytePos, Pos, SourceFile, SourceFileAndLine, Span};
35 use rustc_target::abi::{Primitive, Size};
38 use smallvec::SmallVec;
39 use std::cell::RefCell;
49 pub use self::create_scope_map::compute_mir_scopes;
50 pub use self::metadata::create_global_var_metadata;
51 pub use self::metadata::extend_scope_to_file;
53 #[allow(non_upper_case_globals)]
54 const DW_TAG_auto_variable: c_uint = 0x100;
55 #[allow(non_upper_case_globals)]
56 const DW_TAG_arg_variable: c_uint = 0x101;
58 /// A context object for maintaining all state needed by the debuginfo module.
59 pub struct CrateDebugContext<'a, 'tcx> {
60 llcontext: &'a llvm::Context,
61 llmod: &'a llvm::Module,
62 builder: &'a mut DIBuilder<'a>,
63 created_files: RefCell<FxHashMap<(Option<String>, Option<String>), &'a DIFile>>,
64 created_enum_disr_types: RefCell<FxHashMap<(DefId, Primitive), &'a DIType>>,
66 type_map: RefCell<TypeMap<'a, 'tcx>>,
67 namespace_map: RefCell<DefIdMap<&'a DIScope>>,
69 // This collection is used to assert that composite types (structs, enums,
70 // ...) have their members only set once:
71 composite_types_completed: RefCell<FxHashSet<&'a DIType>>,
74 impl Drop for CrateDebugContext<'_, '_> {
77 llvm::LLVMRustDIBuilderDispose(&mut *(self.builder as *mut _));
82 impl<'a, 'tcx> CrateDebugContext<'a, 'tcx> {
83 pub fn new(llmod: &'a llvm::Module) -> Self {
84 debug!("CrateDebugContext::new");
85 let builder = unsafe { llvm::LLVMRustDIBuilderCreate(llmod) };
86 // DIBuilder inherits context from the module, so we'd better use the same one
87 let llcontext = unsafe { llvm::LLVMGetModuleContext(llmod) };
92 created_files: Default::default(),
93 created_enum_disr_types: Default::default(),
94 type_map: Default::default(),
95 namespace_map: RefCell::new(Default::default()),
96 composite_types_completed: Default::default(),
100 pub fn finalize(&self, sess: &Session) {
102 llvm::LLVMRustDIBuilderFinalize(self.builder);
104 // Debuginfo generation in LLVM by default uses a higher
105 // version of dwarf than macOS currently understands. We can
106 // instruct LLVM to emit an older version of dwarf, however,
107 // for macOS to understand. For more info see #11352
108 // This can be overridden using --llvm-opts -dwarf-version,N.
109 // Android has the same issue (#22398)
110 if let Some(version) = sess.target.dwarf_version {
111 llvm::LLVMRustAddModuleFlag(
113 llvm::LLVMModFlagBehavior::Warning,
114 "Dwarf Version\0".as_ptr().cast(),
119 // Indicate that we want CodeView debug information on MSVC
120 if sess.target.is_like_msvc {
121 llvm::LLVMRustAddModuleFlag(
123 llvm::LLVMModFlagBehavior::Warning,
124 "CodeView\0".as_ptr().cast(),
129 // Prevent bitcode readers from deleting the debug info.
130 let ptr = "Debug Info Version\0".as_ptr();
131 llvm::LLVMRustAddModuleFlag(
133 llvm::LLVMModFlagBehavior::Warning,
135 llvm::LLVMRustDebugMetadataVersion(),
141 /// Creates any deferred debug metadata nodes
142 pub fn finalize(cx: &CodegenCx<'_, '_>) {
143 if let Some(dbg_cx) = &cx.dbg_cx {
146 if gdb::needs_gdb_debug_scripts_section(cx) {
147 // Add a .debug_gdb_scripts section to this compile-unit. This will
148 // cause GDB to try and load the gdb_load_rust_pretty_printers.py file,
149 // which activates the Rust pretty printers for binary this section is
151 gdb::get_or_insert_gdb_debug_scripts_section_global(cx);
154 dbg_cx.finalize(cx.sess());
158 impl<'ll> DebugInfoBuilderMethods for Builder<'_, 'll, '_> {
159 // FIXME(eddyb) find a common convention for all of the debuginfo-related
160 // names (choose between `dbg`, `debug`, `debuginfo`, `debug_info` etc.).
163 dbg_var: &'ll DIVariable,
164 dbg_loc: &'ll DILocation,
165 variable_alloca: Self::Value,
167 indirect_offsets: &[Size],
169 // Convert the direct and indirect offsets to address ops.
170 // FIXME(eddyb) use `const`s instead of getting the values via FFI,
171 // the values should match the ones in the DWARF standard anyway.
172 let op_deref = || unsafe { llvm::LLVMRustDIBuilderCreateOpDeref() };
173 let op_plus_uconst = || unsafe { llvm::LLVMRustDIBuilderCreateOpPlusUconst() };
174 let mut addr_ops = SmallVec::<[u64; 8]>::new();
176 if direct_offset.bytes() > 0 {
177 addr_ops.push(op_plus_uconst());
178 addr_ops.push(direct_offset.bytes() as u64);
180 for &offset in indirect_offsets {
181 addr_ops.push(op_deref());
182 if offset.bytes() > 0 {
183 addr_ops.push(op_plus_uconst());
184 addr_ops.push(offset.bytes() as u64);
189 // FIXME(eddyb) replace `llvm.dbg.declare` with `llvm.dbg.addr`.
190 llvm::LLVMRustDIBuilderInsertDeclareAtEnd(
195 addr_ops.len() as c_uint,
202 fn set_dbg_loc(&mut self, dbg_loc: &'ll DILocation) {
204 let dbg_loc_as_llval = llvm::LLVMRustMetadataAsValue(self.cx().llcx, dbg_loc);
205 llvm::LLVMSetCurrentDebugLocation(self.llbuilder, dbg_loc_as_llval);
209 fn insert_reference_to_gdb_debug_scripts_section_global(&mut self) {
210 gdb::insert_reference_to_gdb_debug_scripts_section_global(self)
213 fn set_var_name(&mut self, value: &'ll Value, name: &str) {
214 // Avoid wasting time if LLVM value names aren't even enabled.
215 if self.sess().fewer_names() {
219 // Only function parameters and instructions are local to a function,
220 // don't change the name of anything else (e.g. globals).
221 let param_or_inst = unsafe {
222 llvm::LLVMIsAArgument(value).is_some() || llvm::LLVMIsAInstruction(value).is_some()
228 // Avoid replacing the name if it already exists.
229 // While we could combine the names somehow, it'd
230 // get noisy quick, and the usefulness is dubious.
231 if llvm::get_value_name(value).is_empty() {
232 llvm::set_value_name(value, name.as_bytes());
237 /// A source code location used to generate debug information.
238 // FIXME(eddyb) rename this to better indicate it's a duplicate of
239 // `rustc_span::Loc` rather than `DILocation`, perhaps by making
240 // `lookup_char_pos` return the right information instead.
241 pub struct DebugLoc {
242 /// Information about the original source file.
243 pub file: Lrc<SourceFile>,
244 /// The (1-based) line number.
246 /// The (1-based) column number.
250 impl CodegenCx<'_, '_> {
251 /// Looks up debug source information about a `BytePos`.
252 // FIXME(eddyb) rename this to better indicate it's a duplicate of
253 // `lookup_char_pos` rather than `dbg_loc`, perhaps by making
254 // `lookup_char_pos` return the right information instead.
255 pub fn lookup_debug_loc(&self, pos: BytePos) -> DebugLoc {
256 let (file, line, col) = match self.sess().source_map().lookup_line(pos) {
257 Ok(SourceFileAndLine { sf: file, line }) => {
258 let line_pos = file.line_begin_pos(pos);
260 // Use 1-based indexing.
261 let line = (line + 1) as u32;
262 let col = (pos - line_pos).to_u32() + 1;
266 Err(file) => (file, UNKNOWN_LINE_NUMBER, UNKNOWN_COLUMN_NUMBER),
269 // For MSVC, omit the column number.
270 // Otherwise, emit it. This mimics clang behaviour.
271 // See discussion in https://github.com/rust-lang/rust/issues/42921
272 if self.sess().target.is_like_msvc {
273 DebugLoc { file, line, col: UNKNOWN_COLUMN_NUMBER }
275 DebugLoc { file, line, col }
280 impl<'ll, 'tcx> DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
281 fn create_function_debug_context(
283 instance: Instance<'tcx>,
284 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
286 mir: &mir::Body<'tcx>,
287 ) -> Option<FunctionDebugContext<&'ll DIScope, &'ll DILocation>> {
288 if self.sess().opts.debuginfo == DebugInfo::None {
292 // Initialize fn debug context (including scopes).
293 // FIXME(eddyb) figure out a way to not need `Option` for `dbg_scope`.
294 let empty_scope = DebugScope {
297 file_start_pos: BytePos(0),
298 file_end_pos: BytePos(0),
300 let mut fn_debug_context =
301 FunctionDebugContext { scopes: IndexVec::from_elem(empty_scope, &mir.source_scopes) };
303 // Fill in all the scopes, with the information from the MIR body.
308 self.dbg_scope_fn(instance, fn_abi, Some(llfn)),
309 &mut fn_debug_context,
312 Some(fn_debug_context)
317 instance: Instance<'tcx>,
318 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
319 maybe_definition_llfn: Option<&'ll Value>,
323 let def_id = instance.def_id();
324 let containing_scope = get_containing_scope(self, instance);
325 let span = tcx.def_span(def_id);
326 let loc = self.lookup_debug_loc(span.lo());
327 let file_metadata = file_metadata(self, &loc.file);
329 let function_type_metadata = unsafe {
330 let fn_signature = get_function_signature(self, fn_abi);
331 llvm::LLVMRustDIBuilderCreateSubroutineType(DIB(self), fn_signature)
334 let mut name = String::new();
335 type_names::push_item_name(tcx, def_id, false, &mut name);
337 // Find the enclosing function, in case this is a closure.
338 let enclosing_fn_def_id = tcx.typeck_root_def_id(def_id);
340 // We look up the generics of the enclosing function and truncate the substs
341 // to their length in order to cut off extra stuff that might be in there for
342 // closures or generators.
343 let generics = tcx.generics_of(enclosing_fn_def_id);
344 let substs = instance.substs.truncate_to(tcx, generics);
346 type_names::push_generic_params(
348 tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), substs),
352 let template_parameters = get_template_parameters(self, generics, substs);
354 let linkage_name = &mangled_name_of_instance(self, instance).name;
355 // Omit the linkage_name if it is the same as subprogram name.
356 let linkage_name = if &name == linkage_name { "" } else { linkage_name };
358 // FIXME(eddyb) does this need to be separate from `loc.line` for some reason?
359 let scope_line = loc.line;
361 let mut flags = DIFlags::FlagPrototyped;
363 if fn_abi.ret.layout.abi.is_uninhabited() {
364 flags |= DIFlags::FlagNoReturn;
367 let mut spflags = DISPFlags::SPFlagDefinition;
368 if is_node_local_to_unit(self, def_id) {
369 spflags |= DISPFlags::SPFlagLocalToUnit;
371 if self.sess().opts.optimize != config::OptLevel::No {
372 spflags |= DISPFlags::SPFlagOptimized;
374 if let Some((id, _)) = tcx.entry_fn(()) {
376 spflags |= DISPFlags::SPFlagMainSubprogram;
381 return llvm::LLVMRustDIBuilderCreateFunction(
384 name.as_ptr().cast(),
386 linkage_name.as_ptr().cast(),
390 function_type_metadata,
394 maybe_definition_llfn,
400 fn get_function_signature<'ll, 'tcx>(
401 cx: &CodegenCx<'ll, 'tcx>,
402 fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
404 if cx.sess().opts.debuginfo == DebugInfo::Limited {
405 return create_DIArray(DIB(cx), &[]);
408 let mut signature = Vec::with_capacity(fn_abi.args.len() + 1);
410 // Return type -- llvm::DIBuilder wants this at index 0
411 signature.push(if fn_abi.ret.is_ignore() {
414 Some(type_metadata(cx, fn_abi.ret.layout.ty))
418 if cx.sess().target.is_like_msvc {
420 // There is a bug in MSDIA that leads to a crash when it encounters
421 // a fixed-size array of `u8` or something zero-sized in a
422 // function-type (see #40477).
423 // As a workaround, we replace those fixed-size arrays with a
424 // pointer-type. So a function `fn foo(a: u8, b: [u8; 4])` would
425 // appear as `fn foo(a: u8, b: *const u8)` in debuginfo,
426 // and a function `fn bar(x: [(); 7])` as `fn bar(x: *const ())`.
427 // This transformed type is wrong, but these function types are
428 // already inaccurate due to ABI adjustments (see #42800).
429 signature.extend(fn_abi.args.iter().map(|arg| {
430 let t = arg.layout.ty;
431 let t = match t.kind() {
433 if (*ct == cx.tcx.types.u8) || cx.layout_of(ct).is_zst() =>
435 cx.tcx.mk_imm_ptr(ct)
439 Some(type_metadata(cx, t))
443 .extend(fn_abi.args.iter().map(|arg| Some(type_metadata(cx, arg.layout.ty))));
446 create_DIArray(DIB(cx), &signature[..])
449 fn get_template_parameters<'ll, 'tcx>(
450 cx: &CodegenCx<'ll, 'tcx>,
451 generics: &ty::Generics,
452 substs: SubstsRef<'tcx>,
454 if substs.types().next().is_none() {
455 return create_DIArray(DIB(cx), &[]);
458 // Again, only create type information if full debuginfo is enabled
459 let template_params: Vec<_> = if cx.sess().opts.debuginfo == DebugInfo::Full {
460 let names = get_parameter_names(cx, generics);
461 iter::zip(substs, names)
462 .filter_map(|(kind, name)| {
463 if let GenericArgKind::Type(ty) = kind.unpack() {
465 cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), ty);
466 let actual_type_metadata = type_metadata(cx, actual_type);
467 let name = name.as_str();
469 Some(llvm::LLVMRustDIBuilderCreateTemplateTypeParameter(
472 name.as_ptr().cast(),
474 actual_type_metadata,
486 create_DIArray(DIB(cx), &template_params)
489 fn get_parameter_names(cx: &CodegenCx<'_, '_>, generics: &ty::Generics) -> Vec<Symbol> {
490 let mut names = generics.parent.map_or_else(Vec::new, |def_id| {
491 get_parameter_names(cx, cx.tcx.generics_of(def_id))
493 names.extend(generics.params.iter().map(|param| param.name));
497 fn get_containing_scope<'ll, 'tcx>(
498 cx: &CodegenCx<'ll, 'tcx>,
499 instance: Instance<'tcx>,
501 // First, let's see if this is a method within an inherent impl. Because
502 // if yes, we want to make the result subroutine DIE a child of the
503 // subroutine's self-type.
504 let self_type = cx.tcx.impl_of_method(instance.def_id()).and_then(|impl_def_id| {
505 // If the method does *not* belong to a trait, proceed
506 if cx.tcx.trait_id_of_impl(impl_def_id).is_none() {
507 let impl_self_ty = cx.tcx.subst_and_normalize_erasing_regions(
509 ty::ParamEnv::reveal_all(),
510 cx.tcx.type_of(impl_def_id),
513 // Only "class" methods are generally understood by LLVM,
514 // so avoid methods on other types (e.g., `<*mut T>::null`).
515 match impl_self_ty.kind() {
516 ty::Adt(def, ..) if !def.is_box() => {
517 // Again, only create type information if full debuginfo is enabled
518 if cx.sess().opts.debuginfo == DebugInfo::Full
519 && !impl_self_ty.needs_subst()
521 Some(type_metadata(cx, impl_self_ty))
523 Some(namespace::item_namespace(cx, def.did))
529 // For trait method impls we still use the "parallel namespace"
535 self_type.unwrap_or_else(|| {
536 namespace::item_namespace(
539 krate: instance.def_id().krate,
542 .def_key(instance.def_id())
544 .expect("get_containing_scope: missing parent?"),
554 inlined_at: Option<&'ll DILocation>,
556 ) -> &'ll DILocation {
557 let DebugLoc { line, col, .. } = self.lookup_debug_loc(span.lo());
559 unsafe { llvm::LLVMRustDIBuilderCreateDebugLocation(line, col, scope, inlined_at) }
562 fn create_vtable_metadata(
565 trait_ref: Option<ty::PolyExistentialTraitRef<'tcx>>,
568 metadata::create_vtable_metadata(self, ty, trait_ref, vtable)
571 fn extend_scope_to_file(
573 scope_metadata: &'ll DIScope,
574 file: &rustc_span::SourceFile,
575 ) -> &'ll DILexicalBlock {
576 metadata::extend_scope_to_file(self, scope_metadata, file)
579 fn debuginfo_finalize(&self) {
583 // FIXME(eddyb) find a common convention for all of the debuginfo-related
584 // names (choose between `dbg`, `debug`, `debuginfo`, `debug_info` etc.).
587 variable_name: Symbol,
588 variable_type: Ty<'tcx>,
589 scope_metadata: &'ll DIScope,
590 variable_kind: VariableKind,
592 ) -> &'ll DIVariable {
593 let loc = self.lookup_debug_loc(span.lo());
594 let file_metadata = file_metadata(self, &loc.file);
596 let type_metadata = type_metadata(self, variable_type);
598 let (argument_index, dwarf_tag) = match variable_kind {
599 ArgumentVariable(index) => (index as c_uint, DW_TAG_arg_variable),
600 LocalVariable => (0, DW_TAG_auto_variable),
602 let align = self.align_of(variable_type);
604 let name = variable_name.as_str();
606 llvm::LLVMRustDIBuilderCreateVariable(
610 name.as_ptr().cast(),
618 align.bytes() as u32,