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