src/librustc_codegen_llvm/debuginfo/mod.rs

   1 // Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // See doc.rs for documentation.
  12 mod doc;
  13
  14 use self::VariableAccess::*;
  15 use self::VariableKind::*;
  16
  17 use self::utils::{DIB, span_start, create_DIArray, is_node_local_to_unit};
  18 use self::namespace::mangled_name_of_instance;
  19 use self::type_names::compute_debuginfo_type_name;
  20 use self::metadata::{type_metadata, file_metadata, TypeMap};
  21 use self::source_loc::InternalDebugLocation::{self, UnknownLocation};
  22
  23 use llvm;
  24 use llvm::debuginfo::{DIFile, DIType, DIScope, DIBuilder, DISubprogram, DIArray, DIFlags};
  25 use rustc::hir::CodegenFnAttrFlags;
  26 use rustc::hir::def_id::{DefId, CrateNum};
  27 use rustc::ty::subst::{Substs, UnpackedKind};
  28
  29 use abi::Abi;
  30 use common::CodegenCx;
  31 use builder::Builder;
  32 use monomorphize::Instance;
  33 use rustc::ty::{self, ParamEnv, Ty, InstanceDef};
  34 use rustc::mir;
  35 use rustc::session::config::{self, DebugInfo};
  36 use rustc::util::nodemap::{DefIdMap, FxHashMap, FxHashSet};
  37 use rustc_data_structures::small_c_str::SmallCStr;
  38 use value::Value;
  39
  40 use libc::c_uint;
  41 use std::cell::{Cell, RefCell};
  42 use std::ffi::CString;
  43
  44 use syntax_pos::{self, Span, Pos};
  45 use syntax::ast;
  46 use syntax::symbol::{Symbol, InternedString};
  47 use rustc::ty::layout::{self, LayoutOf};
  48
  49 pub mod gdb;
  50 mod utils;
  51 mod namespace;
  52 mod type_names;
  53 pub mod metadata;
  54 mod create_scope_map;
  55 mod source_loc;
  56
  57 pub use self::create_scope_map::{create_mir_scopes, MirDebugScope};
  58 pub use self::source_loc::start_emitting_source_locations;
  59 pub use self::metadata::create_global_var_metadata;
  60 pub use self::metadata::create_vtable_metadata;
  61 pub use self::metadata::extend_scope_to_file;
  62 pub use self::source_loc::set_source_location;
  63
  64 #[allow(non_upper_case_globals)]
  65 const DW_TAG_auto_variable: c_uint = 0x100;
  66 #[allow(non_upper_case_globals)]
  67 const DW_TAG_arg_variable: c_uint = 0x101;
  68
  69 /// A context object for maintaining all state needed by the debuginfo module.
  70 pub struct CrateDebugContext<'a, 'tcx> {
  71     llcontext: &'a llvm::Context,
  72     llmod: &'a llvm::Module,
  73     builder: &'a mut DIBuilder<'a>,
  74     created_files: RefCell<FxHashMap<(Symbol, Symbol), &'a DIFile>>,
  75     created_enum_disr_types: RefCell<FxHashMap<(DefId, layout::Primitive), &'a DIType>>,
  76
  77     type_map: RefCell<TypeMap<'a, 'tcx>>,
  78     namespace_map: RefCell<DefIdMap<&'a DIScope>>,
  79
  80     // This collection is used to assert that composite types (structs, enums,
  81     // ...) have their members only set once:
  82     composite_types_completed: RefCell<FxHashSet<&'a DIType>>,
  83 }
  84
  85 impl Drop for CrateDebugContext<'a, 'tcx> {
  86     fn drop(&mut self) {
  87         unsafe {
  88             llvm::LLVMRustDIBuilderDispose(&mut *(self.builder as *mut _));
  89         }
  90     }
  91 }
  92
  93 impl<'a, 'tcx> CrateDebugContext<'a, 'tcx> {
  94     pub fn new(llmod: &'a llvm::Module) -> Self {
  95         debug!("CrateDebugContext::new");
  96         let builder = unsafe { llvm::LLVMRustDIBuilderCreate(llmod) };
  97         // DIBuilder inherits context from the module, so we'd better use the same one
  98         let llcontext = unsafe { llvm::LLVMGetModuleContext(llmod) };
  99         CrateDebugContext {
 100             llcontext,
 101             llmod,
 102             builder,
 103             created_files: Default::default(),
 104             created_enum_disr_types: Default::default(),
 105             type_map: Default::default(),
 106             namespace_map: RefCell::new(DefIdMap()),
 107             composite_types_completed: Default::default(),
 108         }
 109     }
 110 }
 111
 112 pub enum FunctionDebugContext<'ll> {
 113     RegularContext(FunctionDebugContextData<'ll>),
 114     DebugInfoDisabled,
 115     FunctionWithoutDebugInfo,
 116 }
 117
 118 impl FunctionDebugContext<'ll> {
 119     pub fn get_ref<'a>(&'a self, span: Span) -> &'a FunctionDebugContextData<'ll> {
 120         match *self {
 121             FunctionDebugContext::RegularContext(ref data) => data,
 122             FunctionDebugContext::DebugInfoDisabled => {
 123                 span_bug!(span, "{}", FunctionDebugContext::debuginfo_disabled_message());
 124             }
 125             FunctionDebugContext::FunctionWithoutDebugInfo => {
 126                 span_bug!(span, "{}", FunctionDebugContext::should_be_ignored_message());
 127             }
 128         }
 129     }
 130
 131     fn debuginfo_disabled_message() -> &'static str {
 132         "debuginfo: Error trying to access FunctionDebugContext although debug info is disabled!"
 133     }
 134
 135     fn should_be_ignored_message() -> &'static str {
 136         "debuginfo: Error trying to access FunctionDebugContext for function that should be \
 137          ignored by debug info!"
 138     }
 139 }
 140
 141 pub struct FunctionDebugContextData<'ll> {
 142     fn_metadata: &'ll DISubprogram,
 143     source_locations_enabled: Cell<bool>,
 144     pub defining_crate: CrateNum,
 145 }
 146
 147 pub enum VariableAccess<'a, 'll> {
 148     // The llptr given is an alloca containing the variable's value
 149     DirectVariable { alloca: &'ll Value },
 150     // The llptr given is an alloca containing the start of some pointer chain
 151     // leading to the variable's content.
 152     IndirectVariable { alloca: &'ll Value, address_operations: &'a [i64] }
 153 }
 154
 155 pub enum VariableKind {
 156     ArgumentVariable(usize /*index*/),
 157     LocalVariable,
 158 }
 159
 160 /// Create any deferred debug metadata nodes
 161 pub fn finalize(cx: &CodegenCx) {
 162     if cx.dbg_cx.is_none() {
 163         return;
 164     }
 165
 166     debug!("finalize");
 167
 168     if gdb::needs_gdb_debug_scripts_section(cx) {
 169         // Add a .debug_gdb_scripts section to this compile-unit. This will
 170         // cause GDB to try and load the gdb_load_rust_pretty_printers.py file,
 171         // which activates the Rust pretty printers for binary this section is
 172         // contained in.
 173         gdb::get_or_insert_gdb_debug_scripts_section_global(cx);
 174     }
 175
 176     unsafe {
 177         llvm::LLVMRustDIBuilderFinalize(DIB(cx));
 178         // Debuginfo generation in LLVM by default uses a higher
 179         // version of dwarf than macOS currently understands. We can
 180         // instruct LLVM to emit an older version of dwarf, however,
 181         // for macOS to understand. For more info see #11352
 182         // This can be overridden using --llvm-opts -dwarf-version,N.
 183         // Android has the same issue (#22398)
 184         if cx.sess().target.target.options.is_like_osx ||
 185            cx.sess().target.target.options.is_like_android {
 186             llvm::LLVMRustAddModuleFlag(cx.llmod,
 187                                         "Dwarf Version\0".as_ptr() as *const _,
 188                                         2)
 189         }
 190
 191         // Indicate that we want CodeView debug information on MSVC
 192         if cx.sess().target.target.options.is_like_msvc {
 193             llvm::LLVMRustAddModuleFlag(cx.llmod,
 194                                         "CodeView\0".as_ptr() as *const _,
 195                                         1)
 196         }
 197
 198         // Prevent bitcode readers from deleting the debug info.
 199         let ptr = "Debug Info Version\0".as_ptr();
 200         llvm::LLVMRustAddModuleFlag(cx.llmod, ptr as *const _,
 201                                     llvm::LLVMRustDebugMetadataVersion());
 202     };
 203 }
 204
 205 /// Creates the function-specific debug context.
 206 ///
 207 /// Returns the FunctionDebugContext for the function which holds state needed
 208 /// for debug info creation. The function may also return another variant of the
 209 /// FunctionDebugContext enum which indicates why no debuginfo should be created
 210 /// for the function.
 211 pub fn create_function_debug_context(
 212     cx: &CodegenCx<'ll, 'tcx>,
 213     instance: Instance<'tcx>,
 214     sig: ty::FnSig<'tcx>,
 215     llfn: &'ll Value,
 216     mir: &mir::Mir,
 217 ) -> FunctionDebugContext<'ll> {
 218     if cx.sess().opts.debuginfo == DebugInfo::None {
 219         return FunctionDebugContext::DebugInfoDisabled;
 220     }
 221
 222     if let InstanceDef::Item(def_id) = instance.def {
 223         if cx.tcx.codegen_fn_attrs(def_id).flags.contains(CodegenFnAttrFlags::NO_DEBUG) {
 224             return FunctionDebugContext::FunctionWithoutDebugInfo;
 225         }
 226     }
 227
 228     let span = mir.span;
 229
 230     // This can be the case for functions inlined from another crate
 231     if span.is_dummy() {
 232         // FIXME(simulacrum): Probably can't happen; remove.
 233         return FunctionDebugContext::FunctionWithoutDebugInfo;
 234     }
 235
 236     let def_id = instance.def_id();
 237     let containing_scope = get_containing_scope(cx, instance);
 238     let loc = span_start(cx, span);
 239     let file_metadata = file_metadata(cx, &loc.file.name, def_id.krate);
 240
 241     let function_type_metadata = unsafe {
 242         let fn_signature = get_function_signature(cx, sig);
 243         llvm::LLVMRustDIBuilderCreateSubroutineType(DIB(cx), file_metadata, fn_signature)
 244     };
 245
 246     // Find the enclosing function, in case this is a closure.
 247     let def_key = cx.tcx.def_key(def_id);
 248     let mut name = def_key.disambiguated_data.data.to_string();
 249
 250     let enclosing_fn_def_id = cx.tcx.closure_base_def_id(def_id);
 251
 252     // Get_template_parameters() will append a `<...>` clause to the function
 253     // name if necessary.
 254     let generics = cx.tcx.generics_of(enclosing_fn_def_id);
 255     let substs = instance.substs.truncate_to(cx.tcx, generics);
 256     let template_parameters = get_template_parameters(cx,
 257                                                       &generics,
 258                                                       substs,
 259                                                       file_metadata,
 260                                                       &mut name);
 261
 262     // Get the linkage_name, which is just the symbol name
 263     let linkage_name = mangled_name_of_instance(cx, instance);
 264
 265     let scope_line = span_start(cx, span).line;
 266     let is_local_to_unit = is_node_local_to_unit(cx, def_id);
 267
 268     let function_name = CString::new(name).unwrap();
 269     let linkage_name = SmallCStr::new(&linkage_name.as_str());
 270
 271     let mut flags = DIFlags::FlagPrototyped;
 272
 273     let local_id = cx.tcx.hir.as_local_node_id(def_id);
 274     if let Some((id, _, _)) = *cx.sess().entry_fn.borrow() {
 275         if local_id == Some(id) {
 276             flags |= DIFlags::FlagMainSubprogram;
 277         }
 278     }
 279
 280     if cx.layout_of(sig.output()).abi.is_uninhabited() {
 281         flags |= DIFlags::FlagNoReturn;
 282     }
 283
 284     let fn_metadata = unsafe {
 285         llvm::LLVMRustDIBuilderCreateFunction(
 286             DIB(cx),
 287             containing_scope,
 288             function_name.as_ptr(),
 289             linkage_name.as_ptr(),
 290             file_metadata,
 291             loc.line as c_uint,
 292             function_type_metadata,
 293             is_local_to_unit,
 294             true,
 295             scope_line as c_uint,
 296             flags,
 297             cx.sess().opts.optimize != config::OptLevel::No,
 298             llfn,
 299             template_parameters,
 300             None)
 301     };
 302
 303     // Initialize fn debug context (including scope map and namespace map)
 304     let fn_debug_context = FunctionDebugContextData {
 305         fn_metadata,
 306         source_locations_enabled: Cell::new(false),
 307         defining_crate: def_id.krate,
 308     };
 309
 310     return FunctionDebugContext::RegularContext(fn_debug_context);
 311
 312     fn get_function_signature(
 313         cx: &CodegenCx<'ll, 'tcx>,
 314         sig: ty::FnSig<'tcx>,
 315     ) -> &'ll DIArray {
 316         if cx.sess().opts.debuginfo == DebugInfo::Limited {
 317             return create_DIArray(DIB(cx), &[]);
 318         }
 319
 320         let mut signature = Vec::with_capacity(sig.inputs().len() + 1);
 321
 322         // Return type -- llvm::DIBuilder wants this at index 0
 323         signature.push(match sig.output().sty {
 324             ty::Tuple(ref tys) if tys.is_empty() => None,
 325             _ => Some(type_metadata(cx, sig.output(), syntax_pos::DUMMY_SP))
 326         });
 327
 328         let inputs = if sig.abi == Abi::RustCall {
 329             &sig.inputs()[..sig.inputs().len() - 1]
 330         } else {
 331             sig.inputs()
 332         };
 333
 334         // Arguments types
 335         if cx.sess().target.target.options.is_like_msvc {
 336             // FIXME(#42800):
 337             // There is a bug in MSDIA that leads to a crash when it encounters
 338             // a fixed-size array of `u8` or something zero-sized in a
 339             // function-type (see #40477).
 340             // As a workaround, we replace those fixed-size arrays with a
 341             // pointer-type. So a function `fn foo(a: u8, b: [u8; 4])` would
 342             // appear as `fn foo(a: u8, b: *const u8)` in debuginfo,
 343             // and a function `fn bar(x: [(); 7])` as `fn bar(x: *const ())`.
 344             // This transformed type is wrong, but these function types are
 345             // already inaccurate due to ABI adjustments (see #42800).
 346             signature.extend(inputs.iter().map(|&t| {
 347                 let t = match t.sty {
 348                     ty::Array(ct, _)
 349                         if (ct == cx.tcx.types.u8) || cx.layout_of(ct).is_zst() => {
 350                         cx.tcx.mk_imm_ptr(ct)
 351                     }
 352                     _ => t
 353                 };
 354                 Some(type_metadata(cx, t, syntax_pos::DUMMY_SP))
 355             }));
 356         } else {
 357             signature.extend(inputs.iter().map(|t| {
 358                 Some(type_metadata(cx, t, syntax_pos::DUMMY_SP))
 359             }));
 360         }
 361
 362         if sig.abi == Abi::RustCall && !sig.inputs().is_empty() {
 363             if let ty::Tuple(args) = sig.inputs()[sig.inputs().len() - 1].sty {
 364                 signature.extend(
 365                     args.iter().map(|argument_type| {
 366                         Some(type_metadata(cx, argument_type, syntax_pos::DUMMY_SP))
 367                     })
 368                 );
 369             }
 370         }
 371
 372         create_DIArray(DIB(cx), &signature[..])
 373     }
 374
 375     fn get_template_parameters(
 376         cx: &CodegenCx<'ll, 'tcx>,
 377         generics: &ty::Generics,
 378         substs: &Substs<'tcx>,
 379         file_metadata: &'ll DIFile,
 380         name_to_append_suffix_to: &mut String,
 381     ) -> &'ll DIArray {
 382         if substs.types().next().is_none() {
 383             return create_DIArray(DIB(cx), &[]);
 384         }
 385
 386         name_to_append_suffix_to.push('<');
 387         for (i, actual_type) in substs.types().enumerate() {
 388             if i != 0 {
 389                 name_to_append_suffix_to.push_str(",");
 390             }
 391
 392             let actual_type = cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), actual_type);
 393             // Add actual type name to <...> clause of function name
 394             let actual_type_name = compute_debuginfo_type_name(cx,
 395                                                                actual_type,
 396                                                                true);
 397             name_to_append_suffix_to.push_str(&actual_type_name[..]);
 398         }
 399         name_to_append_suffix_to.push('>');
 400
 401         // Again, only create type information if full debuginfo is enabled
 402         let template_params: Vec<_> = if cx.sess().opts.debuginfo == DebugInfo::Full {
 403             let names = get_parameter_names(cx, generics);
 404             substs.iter().zip(names).filter_map(|(kind, name)| {
 405                 if let UnpackedKind::Type(ty) = kind.unpack() {
 406                     let actual_type = cx.tcx.normalize_erasing_regions(ParamEnv::reveal_all(), ty);
 407                     let actual_type_metadata =
 408                         type_metadata(cx, actual_type, syntax_pos::DUMMY_SP);
 409                     let name = SmallCStr::new(&name.as_str());
 410                     Some(unsafe {
 411                         Some(llvm::LLVMRustDIBuilderCreateTemplateTypeParameter(
 412                             DIB(cx),
 413                             None,
 414                             name.as_ptr(),
 415                             actual_type_metadata,
 416                             file_metadata,
 417                             0,
 418                             0,
 419                         ))
 420                     })
 421                 } else {
 422                     None
 423                 }
 424             }).collect()
 425         } else {
 426             vec![]
 427         };
 428
 429         create_DIArray(DIB(cx), &template_params[..])
 430     }
 431
 432     fn get_parameter_names(cx: &CodegenCx,
 433                            generics: &ty::Generics)
 434                            -> Vec<InternedString> {
 435         let mut names = generics.parent.map_or(vec![], |def_id| {
 436             get_parameter_names(cx, cx.tcx.generics_of(def_id))
 437         });
 438         names.extend(generics.params.iter().map(|param| param.name));
 439         names
 440     }
 441
 442     fn get_containing_scope(
 443         cx: &CodegenCx<'ll, 'tcx>,
 444         instance: Instance<'tcx>,
 445     ) -> &'ll DIScope {
 446         // First, let's see if this is a method within an inherent impl. Because
 447         // if yes, we want to make the result subroutine DIE a child of the
 448         // subroutine's self-type.
 449         let self_type = cx.tcx.impl_of_method(instance.def_id()).and_then(|impl_def_id| {
 450             // If the method does *not* belong to a trait, proceed
 451             if cx.tcx.trait_id_of_impl(impl_def_id).is_none() {
 452                 let impl_self_ty = cx.tcx.subst_and_normalize_erasing_regions(
 453                     instance.substs,
 454                     ty::ParamEnv::reveal_all(),
 455                     &cx.tcx.type_of(impl_def_id),
 456                 );
 457
 458                 // Only "class" methods are generally understood by LLVM,
 459                 // so avoid methods on other types (e.g. `<*mut T>::null`).
 460                 match impl_self_ty.sty {
 461                     ty::Adt(def, ..) if !def.is_box() => {
 462                         Some(type_metadata(cx, impl_self_ty, syntax_pos::DUMMY_SP))
 463                     }
 464                     _ => None
 465                 }
 466             } else {
 467                 // For trait method impls we still use the "parallel namespace"
 468                 // strategy
 469                 None
 470             }
 471         });
 472
 473         self_type.unwrap_or_else(|| {
 474             namespace::item_namespace(cx, DefId {
 475                 krate: instance.def_id().krate,
 476                 index: cx.tcx
 477                          .def_key(instance.def_id())
 478                          .parent
 479                          .expect("get_containing_scope: missing parent?")
 480             })
 481         })
 482     }
 483 }
 484
 485 pub fn declare_local(
 486     bx: &Builder<'a, 'll, 'tcx>,
 487     dbg_context: &FunctionDebugContext<'ll>,
 488     variable_name: ast::Name,
 489     variable_type: Ty<'tcx>,
 490     scope_metadata: &'ll DIScope,
 491     variable_access: VariableAccess<'_, 'll>,
 492     variable_kind: VariableKind,
 493     span: Span,
 494 ) {
 495     assert!(!dbg_context.get_ref(span).source_locations_enabled.get());
 496     let cx = bx.cx;
 497
 498     let file = span_start(cx, span).file;
 499     let file_metadata = file_metadata(cx,
 500                                       &file.name,
 501                                       dbg_context.get_ref(span).defining_crate);
 502
 503     let loc = span_start(cx, span);
 504     let type_metadata = type_metadata(cx, variable_type, span);
 505
 506     let (argument_index, dwarf_tag) = match variable_kind {
 507         ArgumentVariable(index) => (index as c_uint, DW_TAG_arg_variable),
 508         LocalVariable => (0, DW_TAG_auto_variable)
 509     };
 510     let align = cx.align_of(variable_type);
 511
 512     let name = SmallCStr::new(&variable_name.as_str());
 513     match (variable_access, &[][..]) {
 514         (DirectVariable { alloca }, address_operations) |
 515         (IndirectVariable {alloca, address_operations}, _) => {
 516             let metadata = unsafe {
 517                 llvm::LLVMRustDIBuilderCreateVariable(
 518                     DIB(cx),
 519                     dwarf_tag,
 520                     scope_metadata,
 521                     name.as_ptr(),
 522                     file_metadata,
 523                     loc.line as c_uint,
 524                     type_metadata,
 525                     cx.sess().opts.optimize != config::OptLevel::No,
 526                     DIFlags::FlagZero,
 527                     argument_index,
 528                     align.abi() as u32,
 529                 )
 530             };
 531             source_loc::set_debug_location(bx,
 532                 InternalDebugLocation::new(scope_metadata, loc.line, loc.col.to_usize()));
 533             unsafe {
 534                 let debug_loc = llvm::LLVMGetCurrentDebugLocation(bx.llbuilder);
 535                 let instr = llvm::LLVMRustDIBuilderInsertDeclareAtEnd(
 536                     DIB(cx),
 537                     alloca,
 538                     metadata,
 539                     address_operations.as_ptr(),
 540                     address_operations.len() as c_uint,
 541                     debug_loc,
 542                     bx.llbb());
 543
 544                 llvm::LLVMSetInstDebugLocation(bx.llbuilder, instr);
 545             }
 546             source_loc::set_debug_location(bx, UnknownLocation);
 547         }
 548     }
 549 }