src/librustc_trans/trans/debuginfo/metadata.rs

   1 // Copyright 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 use self::RecursiveTypeDescription::*;
  12 use self::MemberOffset::*;
  13 use self::MemberDescriptionFactory::*;
  14 use self::EnumDiscriminantInfo::*;
  15
  16 use super::utils::{debug_context, DIB, span_start, bytes_to_bits, size_and_align_of,
  17                    get_namespace_and_span_for_item, create_DIArray,
  18                    fn_should_be_ignored, is_node_local_to_unit};
  19 use super::namespace::namespace_for_item;
  20 use super::type_names::{compute_debuginfo_type_name, push_debuginfo_type_name};
  21 use super::{declare_local, VariableKind, VariableAccess};
  22
  23 use llvm::{self, ValueRef};
  24 use llvm::debuginfo::{DIType, DIFile, DIScope, DIDescriptor, DICompositeType};
  25
  26 use middle::def_id::DefId;
  27 use middle::infer;
  28 use middle::pat_util;
  29 use middle::subst;
  30 use rustc::front::map as hir_map;
  31 use rustc_front::hir::{self, PatKind};
  32 use trans::{type_of, adt, machine, monomorphize};
  33 use trans::common::{self, CrateContext, FunctionContext, Block};
  34 use trans::_match::{BindingInfo, TransBindingMode};
  35 use trans::type_::Type;
  36 use middle::ty::{self, Ty};
  37 use session::config::{self, FullDebugInfo};
  38 use util::nodemap::FnvHashMap;
  39 use util::common::path2cstr;
  40
  41 use libc::{c_uint, c_longlong};
  42 use std::ffi::CString;
  43 use std::path::Path;
  44 use std::ptr;
  45 use std::rc::Rc;
  46 use syntax;
  47 use syntax::util::interner::Interner;
  48 use syntax::codemap::Span;
  49 use syntax::{ast, codemap};
  50 use syntax::parse::token;
  51
  52
  53 const DW_LANG_RUST: c_uint = 0x9000;
  54 #[allow(non_upper_case_globals)]
  55 const DW_ATE_boolean: c_uint = 0x02;
  56 #[allow(non_upper_case_globals)]
  57 const DW_ATE_float: c_uint = 0x04;
  58 #[allow(non_upper_case_globals)]
  59 const DW_ATE_signed: c_uint = 0x05;
  60 #[allow(non_upper_case_globals)]
  61 const DW_ATE_unsigned: c_uint = 0x07;
  62 #[allow(non_upper_case_globals)]
  63 const DW_ATE_unsigned_char: c_uint = 0x08;
  64
  65 pub const UNKNOWN_LINE_NUMBER: c_uint = 0;
  66 pub const UNKNOWN_COLUMN_NUMBER: c_uint = 0;
  67
  68 // ptr::null() doesn't work :(
  69 const NO_FILE_METADATA: DIFile = (0 as DIFile);
  70 const NO_SCOPE_METADATA: DIScope = (0 as DIScope);
  71
  72 const FLAGS_NONE: c_uint = 0;
  73
  74 #[derive(Copy, Debug, Hash, Eq, PartialEq, Clone)]
  75 pub struct UniqueTypeId(ast::Name);
  76
  77 // The TypeMap is where the CrateDebugContext holds the type metadata nodes
  78 // created so far. The metadata nodes are indexed by UniqueTypeId, and, for
  79 // faster lookup, also by Ty. The TypeMap is responsible for creating
  80 // UniqueTypeIds.
  81 pub struct TypeMap<'tcx> {
  82     // The UniqueTypeIds created so far
  83     unique_id_interner: Interner<Rc<String>>,
  84     // A map from UniqueTypeId to debuginfo metadata for that type. This is a 1:1 mapping.
  85     unique_id_to_metadata: FnvHashMap<UniqueTypeId, DIType>,
  86     // A map from types to debuginfo metadata. This is a N:1 mapping.
  87     type_to_metadata: FnvHashMap<Ty<'tcx>, DIType>,
  88     // A map from types to UniqueTypeId. This is a N:1 mapping.
  89     type_to_unique_id: FnvHashMap<Ty<'tcx>, UniqueTypeId>
  90 }
  91
  92 impl<'tcx> TypeMap<'tcx> {
  93     pub fn new() -> TypeMap<'tcx> {
  94         TypeMap {
  95             unique_id_interner: Interner::new(),
  96             type_to_metadata: FnvHashMap(),
  97             unique_id_to_metadata: FnvHashMap(),
  98             type_to_unique_id: FnvHashMap(),
  99         }
 100     }
 101
 102     // Adds a Ty to metadata mapping to the TypeMap. The method will fail if
 103     // the mapping already exists.
 104     fn register_type_with_metadata<'a>(&mut self,
 105                                        cx: &CrateContext<'a, 'tcx>,
 106                                        type_: Ty<'tcx>,
 107                                        metadata: DIType) {
 108         if self.type_to_metadata.insert(type_, metadata).is_some() {
 109             cx.sess().bug(&format!("Type metadata for Ty '{}' is already in the TypeMap!",
 110                                    type_));
 111         }
 112     }
 113
 114     // Adds a UniqueTypeId to metadata mapping to the TypeMap. The method will
 115     // fail if the mapping already exists.
 116     fn register_unique_id_with_metadata(&mut self,
 117                                         cx: &CrateContext,
 118                                         unique_type_id: UniqueTypeId,
 119                                         metadata: DIType) {
 120         if self.unique_id_to_metadata.insert(unique_type_id, metadata).is_some() {
 121             let unique_type_id_str = self.get_unique_type_id_as_string(unique_type_id);
 122             cx.sess().bug(&format!("Type metadata for unique id '{}' is already in the TypeMap!",
 123                                   &unique_type_id_str[..]));
 124         }
 125     }
 126
 127     fn find_metadata_for_type(&self, type_: Ty<'tcx>) -> Option<DIType> {
 128         self.type_to_metadata.get(&type_).cloned()
 129     }
 130
 131     fn find_metadata_for_unique_id(&self, unique_type_id: UniqueTypeId) -> Option<DIType> {
 132         self.unique_id_to_metadata.get(&unique_type_id).cloned()
 133     }
 134
 135     // Get the string representation of a UniqueTypeId. This method will fail if
 136     // the id is unknown.
 137     fn get_unique_type_id_as_string(&self, unique_type_id: UniqueTypeId) -> Rc<String> {
 138         let UniqueTypeId(interner_key) = unique_type_id;
 139         self.unique_id_interner.get(interner_key)
 140     }
 141
 142     // Get the UniqueTypeId for the given type. If the UniqueTypeId for the given
 143     // type has been requested before, this is just a table lookup. Otherwise an
 144     // ID will be generated and stored for later lookup.
 145     fn get_unique_type_id_of_type<'a>(&mut self, cx: &CrateContext<'a, 'tcx>,
 146                                       type_: Ty<'tcx>) -> UniqueTypeId {
 147
 148         // basic type             -> {:name of the type:}
 149         // tuple                  -> {tuple_(:param-uid:)*}
 150         // struct                 -> {struct_:svh: / :node-id:_<(:param-uid:),*> }
 151         // enum                   -> {enum_:svh: / :node-id:_<(:param-uid:),*> }
 152         // enum variant           -> {variant_:variant-name:_:enum-uid:}
 153         // reference (&)          -> {& :pointee-uid:}
 154         // mut reference (&mut)   -> {&mut :pointee-uid:}
 155         // ptr (*)                -> {* :pointee-uid:}
 156         // mut ptr (*mut)         -> {*mut :pointee-uid:}
 157         // unique ptr (box)       -> {box :pointee-uid:}
 158         // @-ptr (@)              -> {@ :pointee-uid:}
 159         // sized vec ([T; x])     -> {[:size:] :element-uid:}
 160         // unsized vec ([T])      -> {[] :element-uid:}
 161         // trait (T)              -> {trait_:svh: / :node-id:_<(:param-uid:),*> }
 162         // closure                -> {<unsafe_> <once_> :store-sigil: |(:param-uid:),* <,_...>| -> \
 163         //                             :return-type-uid: : (:bounds:)*}
 164         // function               -> {<unsafe_> <abi_> fn( (:param-uid:)* <,_...> ) -> \
 165         //                             :return-type-uid:}
 166
 167         match self.type_to_unique_id.get(&type_).cloned() {
 168             Some(unique_type_id) => return unique_type_id,
 169             None => { /* generate one */}
 170         };
 171
 172         let mut unique_type_id = String::with_capacity(256);
 173         unique_type_id.push('{');
 174
 175         match type_.sty {
 176             ty::TyBool     |
 177             ty::TyChar     |
 178             ty::TyStr      |
 179             ty::TyInt(_)   |
 180             ty::TyUint(_)  |
 181             ty::TyFloat(_) => {
 182                 push_debuginfo_type_name(cx, type_, false, &mut unique_type_id);
 183             },
 184             ty::TyEnum(def, substs) => {
 185                 unique_type_id.push_str("enum ");
 186                 from_def_id_and_substs(self, cx, def.did, substs, &mut unique_type_id);
 187             },
 188             ty::TyStruct(def, substs) => {
 189                 unique_type_id.push_str("struct ");
 190                 from_def_id_and_substs(self, cx, def.did, substs, &mut unique_type_id);
 191             },
 192             ty::TyTuple(ref component_types) if component_types.is_empty() => {
 193                 push_debuginfo_type_name(cx, type_, false, &mut unique_type_id);
 194             },
 195             ty::TyTuple(ref component_types) => {
 196                 unique_type_id.push_str("tuple ");
 197                 for &component_type in component_types {
 198                     let component_type_id =
 199                         self.get_unique_type_id_of_type(cx, component_type);
 200                     let component_type_id =
 201                         self.get_unique_type_id_as_string(component_type_id);
 202                     unique_type_id.push_str(&component_type_id[..]);
 203                 }
 204             },
 205             ty::TyBox(inner_type) => {
 206                 unique_type_id.push_str("box ");
 207                 let inner_type_id = self.get_unique_type_id_of_type(cx, inner_type);
 208                 let inner_type_id = self.get_unique_type_id_as_string(inner_type_id);
 209                 unique_type_id.push_str(&inner_type_id[..]);
 210             },
 211             ty::TyRawPtr(ty::TypeAndMut { ty: inner_type, mutbl } ) => {
 212                 unique_type_id.push('*');
 213                 if mutbl == hir::MutMutable {
 214                     unique_type_id.push_str("mut");
 215                 }
 216
 217                 let inner_type_id = self.get_unique_type_id_of_type(cx, inner_type);
 218                 let inner_type_id = self.get_unique_type_id_as_string(inner_type_id);
 219                 unique_type_id.push_str(&inner_type_id[..]);
 220             },
 221             ty::TyRef(_, ty::TypeAndMut { ty: inner_type, mutbl }) => {
 222                 unique_type_id.push('&');
 223                 if mutbl == hir::MutMutable {
 224                     unique_type_id.push_str("mut");
 225                 }
 226
 227                 let inner_type_id = self.get_unique_type_id_of_type(cx, inner_type);
 228                 let inner_type_id = self.get_unique_type_id_as_string(inner_type_id);
 229                 unique_type_id.push_str(&inner_type_id[..]);
 230             },
 231             ty::TyArray(inner_type, len) => {
 232                 unique_type_id.push_str(&format!("[{}]", len));
 233
 234                 let inner_type_id = self.get_unique_type_id_of_type(cx, inner_type);
 235                 let inner_type_id = self.get_unique_type_id_as_string(inner_type_id);
 236                 unique_type_id.push_str(&inner_type_id[..]);
 237             },
 238             ty::TySlice(inner_type) => {
 239                 unique_type_id.push_str("[]");
 240
 241                 let inner_type_id = self.get_unique_type_id_of_type(cx, inner_type);
 242                 let inner_type_id = self.get_unique_type_id_as_string(inner_type_id);
 243                 unique_type_id.push_str(&inner_type_id[..]);
 244             },
 245             ty::TyTrait(ref trait_data) => {
 246                 unique_type_id.push_str("trait ");
 247
 248                 let principal = cx.tcx().erase_late_bound_regions(&trait_data.principal);
 249
 250                 from_def_id_and_substs(self,
 251                                        cx,
 252                                        principal.def_id,
 253                                        principal.substs,
 254                                        &mut unique_type_id);
 255             },
 256             ty::TyBareFn(_, &ty::BareFnTy{ unsafety, abi, ref sig } ) => {
 257                 if unsafety == hir::Unsafety::Unsafe {
 258                     unique_type_id.push_str("unsafe ");
 259                 }
 260
 261                 unique_type_id.push_str(abi.name());
 262
 263                 unique_type_id.push_str(" fn(");
 264
 265                 let sig = cx.tcx().erase_late_bound_regions(sig);
 266                 let sig = infer::normalize_associated_type(cx.tcx(), &sig);
 267
 268                 for &parameter_type in &sig.inputs {
 269                     let parameter_type_id =
 270                         self.get_unique_type_id_of_type(cx, parameter_type);
 271                     let parameter_type_id =
 272                         self.get_unique_type_id_as_string(parameter_type_id);
 273                     unique_type_id.push_str(&parameter_type_id[..]);
 274                     unique_type_id.push(',');
 275                 }
 276
 277                 if sig.variadic {
 278                     unique_type_id.push_str("...");
 279                 }
 280
 281                 unique_type_id.push_str(")->");
 282                 match sig.output {
 283                     ty::FnConverging(ret_ty) => {
 284                         let return_type_id = self.get_unique_type_id_of_type(cx, ret_ty);
 285                         let return_type_id = self.get_unique_type_id_as_string(return_type_id);
 286                         unique_type_id.push_str(&return_type_id[..]);
 287                     }
 288                     ty::FnDiverging => {
 289                         unique_type_id.push_str("!");
 290                     }
 291                 }
 292             },
 293             ty::TyClosure(_, ref substs) if substs.upvar_tys.is_empty() => {
 294                 push_debuginfo_type_name(cx, type_, false, &mut unique_type_id);
 295             },
 296             ty::TyClosure(_, ref substs) => {
 297                 unique_type_id.push_str("closure ");
 298                 for upvar_type in &substs.upvar_tys {
 299                     let upvar_type_id =
 300                         self.get_unique_type_id_of_type(cx, upvar_type);
 301                     let upvar_type_id =
 302                         self.get_unique_type_id_as_string(upvar_type_id);
 303                     unique_type_id.push_str(&upvar_type_id[..]);
 304                 }
 305             },
 306             _ => {
 307                 cx.sess().bug(&format!("get_unique_type_id_of_type() - unexpected type: {:?}",
 308                                        type_))
 309             }
 310         };
 311
 312         unique_type_id.push('}');
 313
 314         // Trim to size before storing permanently
 315         unique_type_id.shrink_to_fit();
 316
 317         let key = self.unique_id_interner.intern(Rc::new(unique_type_id));
 318         self.type_to_unique_id.insert(type_, UniqueTypeId(key));
 319
 320         return UniqueTypeId(key);
 321
 322         fn from_def_id_and_substs<'a, 'tcx>(type_map: &mut TypeMap<'tcx>,
 323                                             cx: &CrateContext<'a, 'tcx>,
 324                                             def_id: DefId,
 325                                             substs: &subst::Substs<'tcx>,
 326                                             output: &mut String) {
 327             // First, find out the 'real' def_id of the type. Items inlined from
 328             // other crates have to be mapped back to their source.
 329             let source_def_id = if let Some(node_id) = cx.tcx().map.as_local_node_id(def_id) {
 330                 match cx.external_srcs().borrow().get(&node_id).cloned() {
 331                     Some(source_def_id) => {
 332                         // The given def_id identifies the inlined copy of a
 333                         // type definition, let's take the source of the copy.
 334                         source_def_id
 335                     }
 336                     None => def_id
 337                 }
 338             } else {
 339                 def_id
 340             };
 341
 342             // Get the crate hash as first part of the identifier.
 343             let crate_hash = if source_def_id.is_local() {
 344                 cx.link_meta().crate_hash.clone()
 345             } else {
 346                 cx.sess().cstore.crate_hash(source_def_id.krate)
 347             };
 348
 349             output.push_str(crate_hash.as_str());
 350             output.push_str("/");
 351             output.push_str(&format!("{:x}", def_id.index.as_usize()));
 352
 353             // Maybe check that there is no self type here.
 354
 355             let tps = substs.types.get_slice(subst::TypeSpace);
 356             if !tps.is_empty() {
 357                 output.push('<');
 358
 359                 for &type_parameter in tps {
 360                     let param_type_id =
 361                         type_map.get_unique_type_id_of_type(cx, type_parameter);
 362                     let param_type_id =
 363                         type_map.get_unique_type_id_as_string(param_type_id);
 364                     output.push_str(&param_type_id[..]);
 365                     output.push(',');
 366                 }
 367
 368                 output.push('>');
 369             }
 370         }
 371     }
 372
 373     // Get the UniqueTypeId for an enum variant. Enum variants are not really
 374     // types of their own, so they need special handling. We still need a
 375     // UniqueTypeId for them, since to debuginfo they *are* real types.
 376     fn get_unique_type_id_of_enum_variant<'a>(&mut self,
 377                                               cx: &CrateContext<'a, 'tcx>,
 378                                               enum_type: Ty<'tcx>,
 379                                               variant_name: &str)
 380                                               -> UniqueTypeId {
 381         let enum_type_id = self.get_unique_type_id_of_type(cx, enum_type);
 382         let enum_variant_type_id = format!("{}::{}",
 383                                            &self.get_unique_type_id_as_string(enum_type_id),
 384                                            variant_name);
 385         let interner_key = self.unique_id_interner.intern(Rc::new(enum_variant_type_id));
 386         UniqueTypeId(interner_key)
 387     }
 388 }
 389
 390 // A description of some recursive type. It can either be already finished (as
 391 // with FinalMetadata) or it is not yet finished, but contains all information
 392 // needed to generate the missing parts of the description. See the
 393 // documentation section on Recursive Types at the top of this file for more
 394 // information.
 395 enum RecursiveTypeDescription<'tcx> {
 396     UnfinishedMetadata {
 397         unfinished_type: Ty<'tcx>,
 398         unique_type_id: UniqueTypeId,
 399         metadata_stub: DICompositeType,
 400         llvm_type: Type,
 401         member_description_factory: MemberDescriptionFactory<'tcx>,
 402     },
 403     FinalMetadata(DICompositeType)
 404 }
 405
 406 fn create_and_register_recursive_type_forward_declaration<'a, 'tcx>(
 407     cx: &CrateContext<'a, 'tcx>,
 408     unfinished_type: Ty<'tcx>,
 409     unique_type_id: UniqueTypeId,
 410     metadata_stub: DICompositeType,
 411     llvm_type: Type,
 412     member_description_factory: MemberDescriptionFactory<'tcx>)
 413  -> RecursiveTypeDescription<'tcx> {
 414
 415     // Insert the stub into the TypeMap in order to allow for recursive references
 416     let mut type_map = debug_context(cx).type_map.borrow_mut();
 417     type_map.register_unique_id_with_metadata(cx, unique_type_id, metadata_stub);
 418     type_map.register_type_with_metadata(cx, unfinished_type, metadata_stub);
 419
 420     UnfinishedMetadata {
 421         unfinished_type: unfinished_type,
 422         unique_type_id: unique_type_id,
 423         metadata_stub: metadata_stub,
 424         llvm_type: llvm_type,
 425         member_description_factory: member_description_factory,
 426     }
 427 }
 428
 429 impl<'tcx> RecursiveTypeDescription<'tcx> {
 430     // Finishes up the description of the type in question (mostly by providing
 431     // descriptions of the fields of the given type) and returns the final type
 432     // metadata.
 433     fn finalize<'a>(&self, cx: &CrateContext<'a, 'tcx>) -> MetadataCreationResult {
 434         match *self {
 435             FinalMetadata(metadata) => MetadataCreationResult::new(metadata, false),
 436             UnfinishedMetadata {
 437                 unfinished_type,
 438                 unique_type_id,
 439                 metadata_stub,
 440                 llvm_type,
 441                 ref member_description_factory,
 442                 ..
 443             } => {
 444                 // Make sure that we have a forward declaration of the type in
 445                 // the TypeMap so that recursive references are possible. This
 446                 // will always be the case if the RecursiveTypeDescription has
 447                 // been properly created through the
 448                 // create_and_register_recursive_type_forward_declaration()
 449                 // function.
 450                 {
 451                     let type_map = debug_context(cx).type_map.borrow();
 452                     if type_map.find_metadata_for_unique_id(unique_type_id).is_none() ||
 453                        type_map.find_metadata_for_type(unfinished_type).is_none() {
 454                         cx.sess().bug(&format!("Forward declaration of potentially recursive type \
 455                                               '{:?}' was not found in TypeMap!",
 456                                               unfinished_type)
 457                                       );
 458                     }
 459                 }
 460
 461                 // ... then create the member descriptions ...
 462                 let member_descriptions =
 463                     member_description_factory.create_member_descriptions(cx);
 464
 465                 // ... and attach them to the stub to complete it.
 466                 set_members_of_composite_type(cx,
 467                                               metadata_stub,
 468                                               llvm_type,
 469                                               &member_descriptions[..]);
 470                 return MetadataCreationResult::new(metadata_stub, true);
 471             }
 472         }
 473     }
 474 }
 475
 476 // Returns from the enclosing function if the type metadata with the given
 477 // unique id can be found in the type map
 478 macro_rules! return_if_metadata_created_in_meantime {
 479     ($cx: expr, $unique_type_id: expr) => (
 480         match debug_context($cx).type_map
 481                                 .borrow()
 482                                 .find_metadata_for_unique_id($unique_type_id) {
 483             Some(metadata) => return MetadataCreationResult::new(metadata, true),
 484             None => { /* proceed normally */ }
 485         }
 486     )
 487 }
 488
 489 fn fixed_vec_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 490                                 unique_type_id: UniqueTypeId,
 491                                 element_type: Ty<'tcx>,
 492                                 len: Option<u64>,
 493                                 span: Span)
 494                                 -> MetadataCreationResult {
 495     let element_type_metadata = type_metadata(cx, element_type, span);
 496
 497     return_if_metadata_created_in_meantime!(cx, unique_type_id);
 498
 499     let element_llvm_type = type_of::type_of(cx, element_type);
 500     let (element_type_size, element_type_align) = size_and_align_of(cx, element_llvm_type);
 501
 502     let (array_size_in_bytes, upper_bound) = match len {
 503         Some(len) => (element_type_size * len, len as c_longlong),
 504         None => (0, -1)
 505     };
 506
 507     let subrange = unsafe {
 508         llvm::LLVMDIBuilderGetOrCreateSubrange(DIB(cx), 0, upper_bound)
 509     };
 510
 511     let subscripts = create_DIArray(DIB(cx), &[subrange]);
 512     let metadata = unsafe {
 513         llvm::LLVMDIBuilderCreateArrayType(
 514             DIB(cx),
 515             bytes_to_bits(array_size_in_bytes),
 516             bytes_to_bits(element_type_align),
 517             element_type_metadata,
 518             subscripts)
 519     };
 520
 521     return MetadataCreationResult::new(metadata, false);
 522 }
 523
 524 fn vec_slice_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 525                                 vec_type: Ty<'tcx>,
 526                                 element_type: Ty<'tcx>,
 527                                 unique_type_id: UniqueTypeId,
 528                                 span: Span)
 529                                 -> MetadataCreationResult {
 530     let data_ptr_type = cx.tcx().mk_ptr(ty::TypeAndMut {
 531         ty: element_type,
 532         mutbl: hir::MutImmutable
 533     });
 534
 535     let element_type_metadata = type_metadata(cx, data_ptr_type, span);
 536
 537     return_if_metadata_created_in_meantime!(cx, unique_type_id);
 538
 539     let slice_llvm_type = type_of::type_of(cx, vec_type);
 540     let slice_type_name = compute_debuginfo_type_name(cx, vec_type, true);
 541
 542     let member_llvm_types = slice_llvm_type.field_types();
 543     assert!(slice_layout_is_correct(cx,
 544                                     &member_llvm_types[..],
 545                                     element_type));
 546     let member_descriptions = [
 547         MemberDescription {
 548             name: "data_ptr".to_string(),
 549             llvm_type: member_llvm_types[0],
 550             type_metadata: element_type_metadata,
 551             offset: ComputedMemberOffset,
 552             flags: FLAGS_NONE
 553         },
 554         MemberDescription {
 555             name: "length".to_string(),
 556             llvm_type: member_llvm_types[1],
 557             type_metadata: type_metadata(cx, cx.tcx().types.usize, span),
 558             offset: ComputedMemberOffset,
 559             flags: FLAGS_NONE
 560         },
 561     ];
 562
 563     assert!(member_descriptions.len() == member_llvm_types.len());
 564
 565     let loc = span_start(cx, span);
 566     let file_metadata = file_metadata(cx, &loc.file.name);
 567
 568     let metadata = composite_type_metadata(cx,
 569                                            slice_llvm_type,
 570                                            &slice_type_name[..],
 571                                            unique_type_id,
 572                                            &member_descriptions,
 573                                            NO_SCOPE_METADATA,
 574                                            file_metadata,
 575                                            span);
 576     return MetadataCreationResult::new(metadata, false);
 577
 578     fn slice_layout_is_correct<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 579                                          member_llvm_types: &[Type],
 580                                          element_type: Ty<'tcx>)
 581                                          -> bool {
 582         member_llvm_types.len() == 2 &&
 583         member_llvm_types[0] == type_of::type_of(cx, element_type).ptr_to() &&
 584         member_llvm_types[1] == cx.int_type()
 585     }
 586 }
 587
 588 fn subroutine_type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 589                                       unique_type_id: UniqueTypeId,
 590                                       signature: &ty::PolyFnSig<'tcx>,
 591                                       span: Span)
 592                                       -> MetadataCreationResult
 593 {
 594     let signature = cx.tcx().erase_late_bound_regions(signature);
 595
 596     let mut signature_metadata: Vec<DIType> = Vec::with_capacity(signature.inputs.len() + 1);
 597
 598     // return type
 599     signature_metadata.push(match signature.output {
 600         ty::FnConverging(ret_ty) => match ret_ty.sty {
 601             ty::TyTuple(ref tys) if tys.is_empty() => ptr::null_mut(),
 602             _ => type_metadata(cx, ret_ty, span)
 603         },
 604         ty::FnDiverging => diverging_type_metadata(cx)
 605     });
 606
 607     // regular arguments
 608     for &argument_type in &signature.inputs {
 609         signature_metadata.push(type_metadata(cx, argument_type, span));
 610     }
 611
 612     return_if_metadata_created_in_meantime!(cx, unique_type_id);
 613
 614     return MetadataCreationResult::new(
 615         unsafe {
 616             llvm::LLVMDIBuilderCreateSubroutineType(
 617                 DIB(cx),
 618                 NO_FILE_METADATA,
 619                 create_DIArray(DIB(cx), &signature_metadata[..]))
 620         },
 621         false);
 622 }
 623
 624 // FIXME(1563) This is all a bit of a hack because 'trait pointer' is an ill-
 625 // defined concept. For the case of an actual trait pointer (i.e., Box<Trait>,
 626 // &Trait), trait_object_type should be the whole thing (e.g, Box<Trait>) and
 627 // trait_type should be the actual trait (e.g., Trait). Where the trait is part
 628 // of a DST struct, there is no trait_object_type and the results of this
 629 // function will be a little bit weird.
 630 fn trait_pointer_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 631                                     trait_type: Ty<'tcx>,
 632                                     trait_object_type: Option<Ty<'tcx>>,
 633                                     unique_type_id: UniqueTypeId)
 634                                     -> DIType {
 635     // The implementation provided here is a stub. It makes sure that the trait
 636     // type is assigned the correct name, size, namespace, and source location.
 637     // But it does not describe the trait's methods.
 638
 639     let def_id = match trait_type.sty {
 640         ty::TyTrait(ref data) => data.principal_def_id(),
 641         _ => {
 642             cx.sess().bug(&format!("debuginfo: Unexpected trait-object type in \
 643                                    trait_pointer_metadata(): {:?}",
 644                                    trait_type));
 645         }
 646     };
 647
 648     let trait_object_type = trait_object_type.unwrap_or(trait_type);
 649     let trait_type_name =
 650         compute_debuginfo_type_name(cx, trait_object_type, false);
 651
 652     let (containing_scope, _) = get_namespace_and_span_for_item(cx, def_id);
 653
 654     let trait_llvm_type = type_of::type_of(cx, trait_object_type);
 655
 656     composite_type_metadata(cx,
 657                             trait_llvm_type,
 658                             &trait_type_name[..],
 659                             unique_type_id,
 660                             &[],
 661                             containing_scope,
 662                             NO_FILE_METADATA,
 663                             codemap::DUMMY_SP)
 664 }
 665
 666 pub fn type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 667                                t: Ty<'tcx>,
 668                                usage_site_span: Span)
 669                                -> DIType {
 670     // Get the unique type id of this type.
 671     let unique_type_id = {
 672         let mut type_map = debug_context(cx).type_map.borrow_mut();
 673         // First, try to find the type in TypeMap. If we have seen it before, we
 674         // can exit early here.
 675         match type_map.find_metadata_for_type(t) {
 676             Some(metadata) => {
 677                 return metadata;
 678             },
 679             None => {
 680                 // The Ty is not in the TypeMap but maybe we have already seen
 681                 // an equivalent type (e.g. only differing in region arguments).
 682                 // In order to find out, generate the unique type id and look
 683                 // that up.
 684                 let unique_type_id = type_map.get_unique_type_id_of_type(cx, t);
 685                 match type_map.find_metadata_for_unique_id(unique_type_id) {
 686                     Some(metadata) => {
 687                         // There is already an equivalent type in the TypeMap.
 688                         // Register this Ty as an alias in the cache and
 689                         // return the cached metadata.
 690                         type_map.register_type_with_metadata(cx, t, metadata);
 691                         return metadata;
 692                     },
 693                     None => {
 694                         // There really is no type metadata for this type, so
 695                         // proceed by creating it.
 696                         unique_type_id
 697                     }
 698                 }
 699             }
 700         }
 701     };
 702
 703     debug!("type_metadata: {:?}", t);
 704
 705     let sty = &t.sty;
 706     let MetadataCreationResult { metadata, already_stored_in_typemap } = match *sty {
 707         ty::TyBool     |
 708         ty::TyChar     |
 709         ty::TyInt(_)   |
 710         ty::TyUint(_)  |
 711         ty::TyFloat(_) => {
 712             MetadataCreationResult::new(basic_type_metadata(cx, t), false)
 713         }
 714         ty::TyTuple(ref elements) if elements.is_empty() => {
 715             MetadataCreationResult::new(basic_type_metadata(cx, t), false)
 716         }
 717         ty::TyEnum(def, _) => {
 718             prepare_enum_metadata(cx,
 719                                   t,
 720                                   def.did,
 721                                   unique_type_id,
 722                                   usage_site_span).finalize(cx)
 723         }
 724         ty::TyArray(typ, len) => {
 725             fixed_vec_metadata(cx, unique_type_id, typ, Some(len as u64), usage_site_span)
 726         }
 727         ty::TySlice(typ) => {
 728             fixed_vec_metadata(cx, unique_type_id, typ, None, usage_site_span)
 729         }
 730         ty::TyStr => {
 731             fixed_vec_metadata(cx, unique_type_id, cx.tcx().types.i8, None, usage_site_span)
 732         }
 733         ty::TyTrait(..) => {
 734             MetadataCreationResult::new(
 735                         trait_pointer_metadata(cx, t, None, unique_type_id),
 736             false)
 737         }
 738         ty::TyBox(ty) |
 739         ty::TyRawPtr(ty::TypeAndMut{ty, ..}) |
 740         ty::TyRef(_, ty::TypeAndMut{ty, ..}) => {
 741             match ty.sty {
 742                 ty::TySlice(typ) => {
 743                     vec_slice_metadata(cx, t, typ, unique_type_id, usage_site_span)
 744                 }
 745                 ty::TyStr => {
 746                     vec_slice_metadata(cx, t, cx.tcx().types.u8, unique_type_id, usage_site_span)
 747                 }
 748                 ty::TyTrait(..) => {
 749                     MetadataCreationResult::new(
 750                         trait_pointer_metadata(cx, ty, Some(t), unique_type_id),
 751                         false)
 752                 }
 753                 _ => {
 754                     let pointee_metadata = type_metadata(cx, ty, usage_site_span);
 755
 756                     match debug_context(cx).type_map
 757                                            .borrow()
 758                                            .find_metadata_for_unique_id(unique_type_id) {
 759                         Some(metadata) => return metadata,
 760                         None => { /* proceed normally */ }
 761                     };
 762
 763                     MetadataCreationResult::new(pointer_type_metadata(cx, t, pointee_metadata),
 764                                                 false)
 765                 }
 766             }
 767         }
 768         ty::TyBareFn(_, ref barefnty) => {
 769             let fn_metadata = subroutine_type_metadata(cx,
 770                                                        unique_type_id,
 771                                                        &barefnty.sig,
 772                                                        usage_site_span).metadata;
 773             match debug_context(cx).type_map
 774                                    .borrow()
 775                                    .find_metadata_for_unique_id(unique_type_id) {
 776                 Some(metadata) => return metadata,
 777                 None => { /* proceed normally */ }
 778             };
 779
 780             // This is actually a function pointer, so wrap it in pointer DI
 781             MetadataCreationResult::new(pointer_type_metadata(cx, t, fn_metadata), false)
 782
 783         }
 784         ty::TyClosure(_, ref substs) => {
 785             prepare_tuple_metadata(cx,
 786                                    t,
 787                                    &substs.upvar_tys,
 788                                    unique_type_id,
 789                                    usage_site_span).finalize(cx)
 790         }
 791         ty::TyStruct(..) => {
 792             prepare_struct_metadata(cx,
 793                                     t,
 794                                     unique_type_id,
 795                                     usage_site_span).finalize(cx)
 796         }
 797         ty::TyTuple(ref elements) => {
 798             prepare_tuple_metadata(cx,
 799                                    t,
 800                                    &elements[..],
 801                                    unique_type_id,
 802                                    usage_site_span).finalize(cx)
 803         }
 804         _ => {
 805             cx.sess().bug(&format!("debuginfo: unexpected type in type_metadata: {:?}",
 806                                   sty))
 807         }
 808     };
 809
 810     {
 811         let mut type_map = debug_context(cx).type_map.borrow_mut();
 812
 813         if already_stored_in_typemap {
 814             // Also make sure that we already have a TypeMap entry for the unique type id.
 815             let metadata_for_uid = match type_map.find_metadata_for_unique_id(unique_type_id) {
 816                 Some(metadata) => metadata,
 817                 None => {
 818                     let unique_type_id_str =
 819                         type_map.get_unique_type_id_as_string(unique_type_id);
 820                     let error_message = format!("Expected type metadata for unique \
 821                                                  type id '{}' to already be in \
 822                                                  the debuginfo::TypeMap but it \
 823                                                  was not. (Ty = {})",
 824                                                 &unique_type_id_str[..],
 825                                                 t);
 826                     cx.sess().span_bug(usage_site_span, &error_message[..]);
 827                 }
 828             };
 829
 830             match type_map.find_metadata_for_type(t) {
 831                 Some(metadata) => {
 832                     if metadata != metadata_for_uid {
 833                         let unique_type_id_str =
 834                             type_map.get_unique_type_id_as_string(unique_type_id);
 835                         let error_message = format!("Mismatch between Ty and \
 836                                                      UniqueTypeId maps in \
 837                                                      debuginfo::TypeMap. \
 838                                                      UniqueTypeId={}, Ty={}",
 839                             &unique_type_id_str[..],
 840                             t);
 841                         cx.sess().span_bug(usage_site_span, &error_message[..]);
 842                     }
 843                 }
 844                 None => {
 845                     type_map.register_type_with_metadata(cx, t, metadata);
 846                 }
 847             }
 848         } else {
 849             type_map.register_type_with_metadata(cx, t, metadata);
 850             type_map.register_unique_id_with_metadata(cx, unique_type_id, metadata);
 851         }
 852     }
 853
 854     metadata
 855 }
 856
 857 pub fn file_metadata(cx: &CrateContext, full_path: &str) -> DIFile {
 858     // FIXME (#9639): This needs to handle non-utf8 paths
 859     let work_dir = cx.sess().working_dir.to_str().unwrap();
 860     let file_name =
 861         if full_path.starts_with(work_dir) {
 862             &full_path[work_dir.len() + 1..full_path.len()]
 863         } else {
 864             full_path
 865         };
 866
 867     file_metadata_(cx, full_path, file_name, &work_dir)
 868 }
 869
 870 pub fn unknown_file_metadata(cx: &CrateContext) -> DIFile {
 871     // Regular filenames should not be empty, so we abuse an empty name as the
 872     // key for the special unknown file metadata
 873     file_metadata_(cx, "", "<unknown>", "")
 874
 875 }
 876
 877 fn file_metadata_(cx: &CrateContext, key: &str, file_name: &str, work_dir: &str) -> DIFile {
 878     match debug_context(cx).created_files.borrow().get(key) {
 879         Some(file_metadata) => return *file_metadata,
 880         None => ()
 881     }
 882
 883     debug!("file_metadata: file_name: {}, work_dir: {}", file_name, work_dir);
 884
 885     let file_name = CString::new(file_name).unwrap();
 886     let work_dir = CString::new(work_dir).unwrap();
 887     let file_metadata = unsafe {
 888         llvm::LLVMDIBuilderCreateFile(DIB(cx), file_name.as_ptr(),
 889                                       work_dir.as_ptr())
 890     };
 891
 892     let mut created_files = debug_context(cx).created_files.borrow_mut();
 893     created_files.insert(key.to_string(), file_metadata);
 894     file_metadata
 895 }
 896
 897 /// Finds the scope metadata node for the given AST node.
 898 pub fn scope_metadata(fcx: &FunctionContext,
 899                   node_id: ast::NodeId,
 900                   error_reporting_span: Span)
 901                -> DIScope {
 902     let scope_map = &fcx.debug_context
 903                         .get_ref(fcx.ccx, error_reporting_span)
 904                         .scope_map;
 905     match scope_map.borrow().get(&node_id).cloned() {
 906         Some(scope_metadata) => scope_metadata,
 907         None => {
 908             let node = fcx.ccx.tcx().map.get(node_id);
 909
 910             fcx.ccx.sess().span_bug(error_reporting_span,
 911                 &format!("debuginfo: Could not find scope info for node {:?}",
 912                         node));
 913         }
 914     }
 915 }
 916
 917 pub fn diverging_type_metadata(cx: &CrateContext) -> DIType {
 918     unsafe {
 919         llvm::LLVMDIBuilderCreateBasicType(
 920             DIB(cx),
 921             "!\0".as_ptr() as *const _,
 922             bytes_to_bits(0),
 923             bytes_to_bits(0),
 924             DW_ATE_unsigned)
 925     }
 926 }
 927
 928 fn basic_type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 929                                  t: Ty<'tcx>) -> DIType {
 930
 931     debug!("basic_type_metadata: {:?}", t);
 932
 933     let (name, encoding) = match t.sty {
 934         ty::TyTuple(ref elements) if elements.is_empty() =>
 935             ("()", DW_ATE_unsigned),
 936         ty::TyBool => ("bool", DW_ATE_boolean),
 937         ty::TyChar => ("char", DW_ATE_unsigned_char),
 938         ty::TyInt(int_ty) => {
 939             (int_ty.ty_to_string(), DW_ATE_signed)
 940         },
 941         ty::TyUint(uint_ty) => {
 942             (uint_ty.ty_to_string(), DW_ATE_unsigned)
 943         },
 944         ty::TyFloat(float_ty) => {
 945             (float_ty.ty_to_string(), DW_ATE_float)
 946         },
 947         _ => cx.sess().bug("debuginfo::basic_type_metadata - t is invalid type")
 948     };
 949
 950     let llvm_type = type_of::type_of(cx, t);
 951     let (size, align) = size_and_align_of(cx, llvm_type);
 952     let name = CString::new(name).unwrap();
 953     let ty_metadata = unsafe {
 954         llvm::LLVMDIBuilderCreateBasicType(
 955             DIB(cx),
 956             name.as_ptr(),
 957             bytes_to_bits(size),
 958             bytes_to_bits(align),
 959             encoding)
 960     };
 961
 962     return ty_metadata;
 963 }
 964
 965 fn pointer_type_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
 966                                    pointer_type: Ty<'tcx>,
 967                                    pointee_type_metadata: DIType)
 968                                    -> DIType {
 969     let pointer_llvm_type = type_of::type_of(cx, pointer_type);
 970     let (pointer_size, pointer_align) = size_and_align_of(cx, pointer_llvm_type);
 971     let name = compute_debuginfo_type_name(cx, pointer_type, false);
 972     let name = CString::new(name).unwrap();
 973     let ptr_metadata = unsafe {
 974         llvm::LLVMDIBuilderCreatePointerType(
 975             DIB(cx),
 976             pointee_type_metadata,
 977             bytes_to_bits(pointer_size),
 978             bytes_to_bits(pointer_align),
 979             name.as_ptr())
 980     };
 981     return ptr_metadata;
 982 }
 983
 984 pub fn compile_unit_metadata(cx: &CrateContext) -> DIDescriptor {
 985     let work_dir = &cx.sess().working_dir;
 986     let compile_unit_name = match cx.sess().local_crate_source_file {
 987         None => fallback_path(cx),
 988         Some(ref abs_path) => {
 989             if abs_path.is_relative() {
 990                 cx.sess().warn("debuginfo: Invalid path to crate's local root source file!");
 991                 fallback_path(cx)
 992             } else {
 993                 match abs_path.strip_prefix(work_dir) {
 994                     Ok(ref p) if p.is_relative() => {
 995                         if p.starts_with(Path::new("./")) {
 996                             path2cstr(p)
 997                         } else {
 998                             path2cstr(&Path::new(".").join(p))
 999                         }
1000                     }
1001                     _ => fallback_path(cx)
1002                 }
1003             }
1004         }
1005     };
1006
1007     debug!("compile_unit_metadata: {:?}", compile_unit_name);
1008     let producer = format!("rustc version {}",
1009                            (option_env!("CFG_VERSION")).expect("CFG_VERSION"));
1010
1011     let compile_unit_name = compile_unit_name.as_ptr();
1012     let work_dir = path2cstr(&work_dir);
1013     let producer = CString::new(producer).unwrap();
1014     let flags = "\0";
1015     let split_name = "\0";
1016     return unsafe {
1017         llvm::LLVMDIBuilderCreateCompileUnit(
1018             debug_context(cx).builder,
1019             DW_LANG_RUST,
1020             compile_unit_name,
1021             work_dir.as_ptr(),
1022             producer.as_ptr(),
1023             cx.sess().opts.optimize != config::OptLevel::No,
1024             flags.as_ptr() as *const _,
1025             0,
1026             split_name.as_ptr() as *const _)
1027     };
1028
1029     fn fallback_path(cx: &CrateContext) -> CString {
1030         CString::new(cx.link_meta().crate_name.clone()).unwrap()
1031     }
1032 }
1033
1034 struct MetadataCreationResult {
1035     metadata: DIType,
1036     already_stored_in_typemap: bool
1037 }
1038
1039 impl MetadataCreationResult {
1040     fn new(metadata: DIType, already_stored_in_typemap: bool) -> MetadataCreationResult {
1041         MetadataCreationResult {
1042             metadata: metadata,
1043             already_stored_in_typemap: already_stored_in_typemap
1044         }
1045     }
1046 }
1047
1048 #[derive(Debug)]
1049 enum MemberOffset {
1050     FixedMemberOffset { bytes: usize },
1051     // For ComputedMemberOffset, the offset is read from the llvm type definition.
1052     ComputedMemberOffset
1053 }
1054
1055 // Description of a type member, which can either be a regular field (as in
1056 // structs or tuples) or an enum variant.
1057 #[derive(Debug)]
1058 struct MemberDescription {
1059     name: String,
1060     llvm_type: Type,
1061     type_metadata: DIType,
1062     offset: MemberOffset,
1063     flags: c_uint
1064 }
1065
1066 // A factory for MemberDescriptions. It produces a list of member descriptions
1067 // for some record-like type. MemberDescriptionFactories are used to defer the
1068 // creation of type member descriptions in order to break cycles arising from
1069 // recursive type definitions.
1070 enum MemberDescriptionFactory<'tcx> {
1071     StructMDF(StructMemberDescriptionFactory<'tcx>),
1072     TupleMDF(TupleMemberDescriptionFactory<'tcx>),
1073     EnumMDF(EnumMemberDescriptionFactory<'tcx>),
1074     VariantMDF(VariantMemberDescriptionFactory<'tcx>)
1075 }
1076
1077 impl<'tcx> MemberDescriptionFactory<'tcx> {
1078     fn create_member_descriptions<'a>(&self, cx: &CrateContext<'a, 'tcx>)
1079                                       -> Vec<MemberDescription> {
1080         match *self {
1081             StructMDF(ref this) => {
1082                 this.create_member_descriptions(cx)
1083             }
1084             TupleMDF(ref this) => {
1085                 this.create_member_descriptions(cx)
1086             }
1087             EnumMDF(ref this) => {
1088                 this.create_member_descriptions(cx)
1089             }
1090             VariantMDF(ref this) => {
1091                 this.create_member_descriptions(cx)
1092             }
1093         }
1094     }
1095 }
1096
1097 //=-----------------------------------------------------------------------------
1098 // Structs
1099 //=-----------------------------------------------------------------------------
1100
1101 // Creates MemberDescriptions for the fields of a struct
1102 struct StructMemberDescriptionFactory<'tcx> {
1103     variant: ty::VariantDef<'tcx>,
1104     substs: &'tcx subst::Substs<'tcx>,
1105     is_simd: bool,
1106     span: Span,
1107 }
1108
1109 impl<'tcx> StructMemberDescriptionFactory<'tcx> {
1110     fn create_member_descriptions<'a>(&self, cx: &CrateContext<'a, 'tcx>)
1111                                       -> Vec<MemberDescription> {
1112         if let ty::VariantKind::Unit = self.variant.kind() {
1113             return Vec::new();
1114         }
1115
1116         let field_size = if self.is_simd {
1117             let fty = monomorphize::field_ty(cx.tcx(),
1118                                              self.substs,
1119                                              &self.variant.fields[0]);
1120             Some(machine::llsize_of_alloc(
1121                 cx,
1122                 type_of::type_of(cx, fty)
1123             ) as usize)
1124         } else {
1125             None
1126         };
1127
1128         self.variant.fields.iter().enumerate().map(|(i, f)| {
1129             let name = if let ty::VariantKind::Tuple = self.variant.kind() {
1130                 format!("__{}", i)
1131             } else {
1132                 f.name.to_string()
1133             };
1134             let fty = monomorphize::field_ty(cx.tcx(), self.substs, f);
1135
1136             let offset = if self.is_simd {
1137                 FixedMemberOffset { bytes: i * field_size.unwrap() }
1138             } else {
1139                 ComputedMemberOffset
1140             };
1141
1142             MemberDescription {
1143                 name: name,
1144                 llvm_type: type_of::type_of(cx, fty),
1145                 type_metadata: type_metadata(cx, fty, self.span),
1146                 offset: offset,
1147                 flags: FLAGS_NONE,
1148             }
1149         }).collect()
1150     }
1151 }
1152
1153
1154 fn prepare_struct_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
1155                                      struct_type: Ty<'tcx>,
1156                                      unique_type_id: UniqueTypeId,
1157                                      span: Span)
1158                                      -> RecursiveTypeDescription<'tcx> {
1159     let struct_name = compute_debuginfo_type_name(cx, struct_type, false);
1160     let struct_llvm_type = type_of::in_memory_type_of(cx, struct_type);
1161
1162     let (variant, substs) = match struct_type.sty {
1163         ty::TyStruct(def, substs) => (def.struct_variant(), substs),
1164         _ => cx.tcx().sess.bug("prepare_struct_metadata on a non-struct")
1165     };
1166
1167     let (containing_scope, _) = get_namespace_and_span_for_item(cx, variant.did);
1168
1169     let struct_metadata_stub = create_struct_stub(cx,
1170                                                   struct_llvm_type,
1171                                                   &struct_name,
1172                                                   unique_type_id,
1173                                                   containing_scope);
1174
1175     create_and_register_recursive_type_forward_declaration(
1176         cx,
1177         struct_type,
1178         unique_type_id,
1179         struct_metadata_stub,
1180         struct_llvm_type,
1181         StructMDF(StructMemberDescriptionFactory {
1182             variant: variant,
1183             substs: substs,
1184             is_simd: struct_type.is_simd(),
1185             span: span,
1186         })
1187     )
1188 }
1189
1190
1191 //=-----------------------------------------------------------------------------
1192 // Tuples
1193 //=-----------------------------------------------------------------------------
1194
1195 // Creates MemberDescriptions for the fields of a tuple
1196 struct TupleMemberDescriptionFactory<'tcx> {
1197     component_types: Vec<Ty<'tcx>>,
1198     span: Span,
1199 }
1200
1201 impl<'tcx> TupleMemberDescriptionFactory<'tcx> {
1202     fn create_member_descriptions<'a>(&self, cx: &CrateContext<'a, 'tcx>)
1203                                       -> Vec<MemberDescription> {
1204         self.component_types
1205             .iter()
1206             .enumerate()
1207             .map(|(i, &component_type)| {
1208             MemberDescription {
1209                 name: format!("__{}", i),
1210                 llvm_type: type_of::type_of(cx, component_type),
1211                 type_metadata: type_metadata(cx, component_type, self.span),
1212                 offset: ComputedMemberOffset,
1213                 flags: FLAGS_NONE,
1214             }
1215         }).collect()
1216     }
1217 }
1218
1219 fn prepare_tuple_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
1220                                     tuple_type: Ty<'tcx>,
1221                                     component_types: &[Ty<'tcx>],
1222                                     unique_type_id: UniqueTypeId,
1223                                     span: Span)
1224                                     -> RecursiveTypeDescription<'tcx> {
1225     let tuple_name = compute_debuginfo_type_name(cx, tuple_type, false);
1226     let tuple_llvm_type = type_of::type_of(cx, tuple_type);
1227
1228     create_and_register_recursive_type_forward_declaration(
1229         cx,
1230         tuple_type,
1231         unique_type_id,
1232         create_struct_stub(cx,
1233                            tuple_llvm_type,
1234                            &tuple_name[..],
1235                            unique_type_id,
1236                            NO_SCOPE_METADATA),
1237         tuple_llvm_type,
1238         TupleMDF(TupleMemberDescriptionFactory {
1239             component_types: component_types.to_vec(),
1240             span: span,
1241         })
1242     )
1243 }
1244
1245
1246 //=-----------------------------------------------------------------------------
1247 // Enums
1248 //=-----------------------------------------------------------------------------
1249
1250 // Describes the members of an enum value: An enum is described as a union of
1251 // structs in DWARF. This MemberDescriptionFactory provides the description for
1252 // the members of this union; so for every variant of the given enum, this
1253 // factory will produce one MemberDescription (all with no name and a fixed
1254 // offset of zero bytes).
1255 struct EnumMemberDescriptionFactory<'tcx> {
1256     enum_type: Ty<'tcx>,
1257     type_rep: Rc<adt::Repr<'tcx>>,
1258     discriminant_type_metadata: Option<DIType>,
1259     containing_scope: DIScope,
1260     file_metadata: DIFile,
1261     span: Span,
1262 }
1263
1264 impl<'tcx> EnumMemberDescriptionFactory<'tcx> {
1265     fn create_member_descriptions<'a>(&self, cx: &CrateContext<'a, 'tcx>)
1266                                       -> Vec<MemberDescription> {
1267         let adt = &self.enum_type.ty_adt_def().unwrap();
1268         match *self.type_rep {
1269             adt::General(_, ref struct_defs, _) => {
1270                 let discriminant_info = RegularDiscriminant(self.discriminant_type_metadata
1271                     .expect(""));
1272                 struct_defs
1273                     .iter()
1274                     .enumerate()
1275                     .map(|(i, struct_def)| {
1276                         let (variant_type_metadata,
1277                              variant_llvm_type,
1278                              member_desc_factory) =
1279                             describe_enum_variant(cx,
1280                                                   self.enum_type,
1281                                                   struct_def,
1282                                                   &adt.variants[i],
1283                                                   discriminant_info,
1284                                                   self.containing_scope,
1285                                                   self.span);
1286
1287                         let member_descriptions = member_desc_factory
1288                             .create_member_descriptions(cx);
1289
1290                         set_members_of_composite_type(cx,
1291                                                       variant_type_metadata,
1292                                                       variant_llvm_type,
1293                                                       &member_descriptions);
1294                         MemberDescription {
1295                             name: "".to_string(),
1296                             llvm_type: variant_llvm_type,
1297                             type_metadata: variant_type_metadata,
1298                             offset: FixedMemberOffset { bytes: 0 },
1299                             flags: FLAGS_NONE
1300                         }
1301                     }).collect()
1302             },
1303             adt::Univariant(ref struct_def, _) => {
1304                 assert!(adt.variants.len() <= 1);
1305
1306                 if adt.variants.is_empty() {
1307                     vec![]
1308                 } else {
1309                     let (variant_type_metadata,
1310                          variant_llvm_type,
1311                          member_description_factory) =
1312                         describe_enum_variant(cx,
1313                                               self.enum_type,
1314                                               struct_def,
1315                                               &adt.variants[0],
1316                                               NoDiscriminant,
1317                                               self.containing_scope,
1318                                               self.span);
1319
1320                     let member_descriptions =
1321                         member_description_factory.create_member_descriptions(cx);
1322
1323                     set_members_of_composite_type(cx,
1324                                                   variant_type_metadata,
1325                                                   variant_llvm_type,
1326                                                   &member_descriptions[..]);
1327                     vec![
1328                         MemberDescription {
1329                             name: "".to_string(),
1330                             llvm_type: variant_llvm_type,
1331                             type_metadata: variant_type_metadata,
1332                             offset: FixedMemberOffset { bytes: 0 },
1333                             flags: FLAGS_NONE
1334                         }
1335                     ]
1336                 }
1337             }
1338             adt::RawNullablePointer { nndiscr: non_null_variant_index, nnty, .. } => {
1339                 // As far as debuginfo is concerned, the pointer this enum
1340                 // represents is still wrapped in a struct. This is to make the
1341                 // DWARF representation of enums uniform.
1342
1343                 // First create a description of the artificial wrapper struct:
1344                 let non_null_variant = &adt.variants[non_null_variant_index.0 as usize];
1345                 let non_null_variant_name = non_null_variant.name.as_str();
1346
1347                 // The llvm type and metadata of the pointer
1348                 let non_null_llvm_type = type_of::type_of(cx, nnty);
1349                 let non_null_type_metadata = type_metadata(cx, nnty, self.span);
1350
1351                 // The type of the artificial struct wrapping the pointer
1352                 let artificial_struct_llvm_type = Type::struct_(cx,
1353                                                                 &[non_null_llvm_type],
1354                                                                 false);
1355
1356                 // For the metadata of the wrapper struct, we need to create a
1357                 // MemberDescription of the struct's single field.
1358                 let sole_struct_member_description = MemberDescription {
1359                     name: match non_null_variant.kind() {
1360                         ty::VariantKind::Tuple => "__0".to_string(),
1361                         ty::VariantKind::Struct => {
1362                             non_null_variant.fields[0].name.to_string()
1363                         }
1364                         ty::VariantKind::Unit => unreachable!()
1365                     },
1366                     llvm_type: non_null_llvm_type,
1367                     type_metadata: non_null_type_metadata,
1368                     offset: FixedMemberOffset { bytes: 0 },
1369                     flags: FLAGS_NONE
1370                 };
1371
1372                 let unique_type_id = debug_context(cx).type_map
1373                                                       .borrow_mut()
1374                                                       .get_unique_type_id_of_enum_variant(
1375                                                           cx,
1376                                                           self.enum_type,
1377                                                           &non_null_variant_name);
1378
1379                 // Now we can create the metadata of the artificial struct
1380                 let artificial_struct_metadata =
1381                     composite_type_metadata(cx,
1382                                             artificial_struct_llvm_type,
1383                                             &non_null_variant_name,
1384                                             unique_type_id,
1385                                             &[sole_struct_member_description],
1386                                             self.containing_scope,
1387                                             self.file_metadata,
1388                                             codemap::DUMMY_SP);
1389
1390                 // Encode the information about the null variant in the union
1391                 // member's name.
1392                 let null_variant_index = (1 - non_null_variant_index.0) as usize;
1393                 let null_variant_name = adt.variants[null_variant_index].name;
1394                 let union_member_name = format!("RUST$ENCODED$ENUM${}${}",
1395                                                 0,
1396                                                 null_variant_name);
1397
1398                 // Finally create the (singleton) list of descriptions of union
1399                 // members.
1400                 vec![
1401                     MemberDescription {
1402                         name: union_member_name,
1403                         llvm_type: artificial_struct_llvm_type,
1404                         type_metadata: artificial_struct_metadata,
1405                         offset: FixedMemberOffset { bytes: 0 },
1406                         flags: FLAGS_NONE
1407                     }
1408                 ]
1409             },
1410             adt::StructWrappedNullablePointer { nonnull: ref struct_def,
1411                                                 nndiscr,
1412                                                 ref discrfield, ..} => {
1413                 // Create a description of the non-null variant
1414                 let (variant_type_metadata, variant_llvm_type, member_description_factory) =
1415                     describe_enum_variant(cx,
1416                                           self.enum_type,
1417                                           struct_def,
1418                                           &adt.variants[nndiscr.0 as usize],
1419                                           OptimizedDiscriminant,
1420                                           self.containing_scope,
1421                                           self.span);
1422
1423                 let variant_member_descriptions =
1424                     member_description_factory.create_member_descriptions(cx);
1425
1426                 set_members_of_composite_type(cx,
1427                                               variant_type_metadata,
1428                                               variant_llvm_type,
1429                                               &variant_member_descriptions[..]);
1430
1431                 // Encode the information about the null variant in the union
1432                 // member's name.
1433                 let null_variant_index = (1 - nndiscr.0) as usize;
1434                 let null_variant_name = adt.variants[null_variant_index].name;
1435                 let discrfield = discrfield.iter()
1436                                            .skip(1)
1437                                            .map(|x| x.to_string())
1438                                            .collect::<Vec<_>>().join("$");
1439                 let union_member_name = format!("RUST$ENCODED$ENUM${}${}",
1440                                                 discrfield,
1441                                                 null_variant_name);
1442
1443                 // Create the (singleton) list of descriptions of union members.
1444                 vec![
1445                     MemberDescription {
1446                         name: union_member_name,
1447                         llvm_type: variant_llvm_type,
1448                         type_metadata: variant_type_metadata,
1449                         offset: FixedMemberOffset { bytes: 0 },
1450                         flags: FLAGS_NONE
1451                     }
1452                 ]
1453             },
1454             adt::CEnum(..) => cx.sess().span_bug(self.span, "This should be unreachable.")
1455         }
1456     }
1457 }
1458
1459 // Creates MemberDescriptions for the fields of a single enum variant.
1460 struct VariantMemberDescriptionFactory<'tcx> {
1461     args: Vec<(String, Ty<'tcx>)>,
1462     discriminant_type_metadata: Option<DIType>,
1463     span: Span,
1464 }
1465
1466 impl<'tcx> VariantMemberDescriptionFactory<'tcx> {
1467     fn create_member_descriptions<'a>(&self, cx: &CrateContext<'a, 'tcx>)
1468                                       -> Vec<MemberDescription> {
1469         self.args.iter().enumerate().map(|(i, &(ref name, ty))| {
1470             MemberDescription {
1471                 name: name.to_string(),
1472                 llvm_type: type_of::type_of(cx, ty),
1473                 type_metadata: match self.discriminant_type_metadata {
1474                     Some(metadata) if i == 0 => metadata,
1475                     _ => type_metadata(cx, ty, self.span)
1476                 },
1477                 offset: ComputedMemberOffset,
1478                 flags: FLAGS_NONE
1479             }
1480         }).collect()
1481     }
1482 }
1483
1484 #[derive(Copy, Clone)]
1485 enum EnumDiscriminantInfo {
1486     RegularDiscriminant(DIType),
1487     OptimizedDiscriminant,
1488     NoDiscriminant
1489 }
1490
1491 // Returns a tuple of (1) type_metadata_stub of the variant, (2) the llvm_type
1492 // of the variant, and (3) a MemberDescriptionFactory for producing the
1493 // descriptions of the fields of the variant. This is a rudimentary version of a
1494 // full RecursiveTypeDescription.
1495 fn describe_enum_variant<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
1496                                    enum_type: Ty<'tcx>,
1497                                    struct_def: &adt::Struct<'tcx>,
1498                                    variant: ty::VariantDef<'tcx>,
1499                                    discriminant_info: EnumDiscriminantInfo,
1500                                    containing_scope: DIScope,
1501                                    span: Span)
1502                                    -> (DICompositeType, Type, MemberDescriptionFactory<'tcx>) {
1503     let variant_llvm_type =
1504         Type::struct_(cx, &struct_def.fields
1505                                     .iter()
1506                                     .map(|&t| type_of::type_of(cx, t))
1507                                     .collect::<Vec<_>>()
1508                                     ,
1509                       struct_def.packed);
1510     // Could do some consistency checks here: size, align, field count, discr type
1511
1512     let variant_name = variant.name.as_str();
1513     let unique_type_id = debug_context(cx).type_map
1514                                           .borrow_mut()
1515                                           .get_unique_type_id_of_enum_variant(
1516                                               cx,
1517                                               enum_type,
1518                                               &variant_name);
1519
1520     let metadata_stub = create_struct_stub(cx,
1521                                            variant_llvm_type,
1522                                            &variant_name,
1523                                            unique_type_id,
1524                                            containing_scope);
1525
1526     // Get the argument names from the enum variant info
1527     let mut arg_names: Vec<_> = match variant.kind() {
1528         ty::VariantKind::Unit => vec![],
1529         ty::VariantKind::Tuple => {
1530             variant.fields
1531                    .iter()
1532                    .enumerate()
1533                    .map(|(i, _)| format!("__{}", i))
1534                    .collect()
1535         }
1536         ty::VariantKind::Struct => {
1537             variant.fields
1538                    .iter()
1539                    .map(|f| f.name.to_string())
1540                    .collect()
1541         }
1542     };
1543
1544     // If this is not a univariant enum, there is also the discriminant field.
1545     match discriminant_info {
1546         RegularDiscriminant(_) => arg_names.insert(0, "RUST$ENUM$DISR".to_string()),
1547         _ => { /* do nothing */ }
1548     };
1549
1550     // Build an array of (field name, field type) pairs to be captured in the factory closure.
1551     let args: Vec<(String, Ty)> = arg_names.iter()
1552         .zip(&struct_def.fields)
1553         .map(|(s, &t)| (s.to_string(), t))
1554         .collect();
1555
1556     let member_description_factory =
1557         VariantMDF(VariantMemberDescriptionFactory {
1558             args: args,
1559             discriminant_type_metadata: match discriminant_info {
1560                 RegularDiscriminant(discriminant_type_metadata) => {
1561                     Some(discriminant_type_metadata)
1562                 }
1563                 _ => None
1564             },
1565             span: span,
1566         });
1567
1568     (metadata_stub, variant_llvm_type, member_description_factory)
1569 }
1570
1571 fn prepare_enum_metadata<'a, 'tcx>(cx: &CrateContext<'a, 'tcx>,
1572                                    enum_type: Ty<'tcx>,
1573                                    enum_def_id: DefId,
1574                                    unique_type_id: UniqueTypeId,
1575                                    span: Span)
1576                                    -> RecursiveTypeDescription<'tcx> {
1577     let enum_name = compute_debuginfo_type_name(cx, enum_type, false);
1578
1579     let (containing_scope, _) = get_namespace_and_span_for_item(cx, enum_def_id);
1580     // FIXME: This should emit actual file metadata for the enum, but we
1581     // currently can't get the necessary information when it comes to types
1582     // imported from other crates. Formerly we violated the ODR when performing
1583     // LTO because we emitted debuginfo for the same type with varying file
1584     // metadata, so as a workaround we pretend that the type comes from
1585     // <unknown>
1586     let file_metadata = unknown_file_metadata(cx);
1587
1588     let variants = &enum_type.ty_adt_def().unwrap().variants;
1589
1590     let enumerators_metadata: Vec<DIDescriptor> = variants
1591         .iter()
1592         .map(|v| {
1593             let token = v.name.as_str();
1594             let name = CString::new(token.as_bytes()).unwrap();
1595             unsafe {
1596                 llvm::LLVMDIBuilderCreateEnumerator(
1597                     DIB(cx),
1598                     name.as_ptr(),
1599                     v.disr_val as u64)
1600             }
1601         })
1602         .collect();
1603
1604     let discriminant_type_metadata = |inttype: syntax::attr::IntType| {
1605         let disr_type_key = (enum_def_id, inttype);
1606         let cached_discriminant_type_metadata = debug_context(cx).created_enum_disr_types
1607                                                                  .borrow()
1608                                                                  .get(&disr_type_key).cloned();
1609         match cached_discriminant_type_metadata {
1610             Some(discriminant_type_metadata) => discriminant_type_metadata,
1611             None => {
1612                 let discriminant_llvm_type = adt::ll_inttype(cx, inttype);
1613                 let (discriminant_size, discriminant_align) =
1614                     size_and_align_of(cx, discriminant_llvm_type);
1615                 let discriminant_base_type_metadata =
1616                     type_metadata(cx,
1617                                   adt::ty_of_inttype(cx.tcx(), inttype),
1618                                   codemap::DUMMY_SP);
1619                 let discriminant_name = get_enum_discriminant_name(cx, enum_def_id);
1620
1621                 let name = CString::new(discriminant_name.as_bytes()).unwrap();
1622                 let discriminant_type_metadata = unsafe {
1623                     llvm::LLVMDIBuilderCreateEnumerationType(
1624                         DIB(cx),
1625                         containing_scope,
1626                         name.as_ptr(),
1627                         NO_FILE_METADATA,
1628                         UNKNOWN_LINE_NUMBER,
1629                         bytes_to_bits(discriminant_size),
1630                         bytes_to_bits(discriminant_align),
1631                         create_DIArray(DIB(cx), &enumerators_metadata),
1632                         discriminant_base_type_metadata)
1633                 };
1634
1635                 debug_context(cx).created_enum_disr_types
1636                                  .borrow_mut()
1637                                  .insert(disr_type_key, discriminant_type_metadata);
1638
1639                 discriminant_type_metadata
1640             }
1641         }
1642     };
1643
1644     let type_rep = adt::represent_type(cx, enum_type);
1645
1646     let discriminant_type_metadata = match *type_rep {
1647         adt::CEnum(inttype, _, _) => {
1648             return FinalMetadata(discriminant_type_metadata(inttype))
1649         },
1650         adt::RawNullablePointer { .. }           |
1651         adt::StructWrappedNullablePointer { .. } |
1652         adt::Univariant(..)                      => None,
1653         adt::General(inttype, _, _) => Some(discriminant_type_metadata(inttype)),
1654     };
1655
1656     let enum_llvm_type = type_of::type_of(cx, enum_type);
1657     let (enum_type_size, enum_type_align) = size_and_align_of(cx, enum_llvm_type);
1658
1659     let unique_type_id_str = debug_context(cx)
1660                              .type_map
1661                              .borrow()
1662                              .get_unique_type_id_as_string(unique_type_id);
1663
1664     let enum_name = CString::new(enum_name).unwrap();
1665     let unique_type_id_str = CString::new(unique_type_id_str.as_bytes()).unwrap();
1666     let enum_metadata = unsafe {
1667         llvm::LLVMDIBuilderCreateUnionType(
1668         DIB(cx),
1669         containing_scope,
1670         enum_name.as_ptr(),
1671         file_metadata,
1672         UNKNOWN_LINE_NUMBER,
1673         bytes_to_bits(enum_type_size),
1674         bytes_to_bits(enum_type_align),
1675         0, // Flags
1676         ptr::null_mut(),
1677         0, // RuntimeLang
1678         unique_type_id_str.as_ptr())
1679     };
1680
1681     return create_and_register_recursive_type_forward_declaration(
1682         cx,
1683         enum_type,
1684         unique_type_id,
1685         enum_metadata,
1686         enum_llvm_type,
1687         EnumMDF(EnumMemberDescriptionFactory {
1688             enum_type: enum_type,
1689             type_rep: type_rep.clone(),
1690             discriminant_type_metadata: discriminant_type_metadata,
1691             containing_scope: containing_scope,
1692             file_metadata: file_metadata,
1693             span: span,
1694         }),
1695     );
1696
1697     fn get_enum_discriminant_name(cx: &CrateContext,
1698                                   def_id: DefId)
1699                                   -> token::InternedString {
1700         cx.tcx().item_name(def_id).as_str()
1701     }
1702 }
1703
1704 /// Creates debug information for a composite type, that is, anything that
1705 /// results in a LLVM struct.
1706 ///
1707 /// Examples of Rust types to use this are: structs, tuples, boxes, vecs, and enums.
1708 fn composite_type_metadata(cx: &CrateContext,
1709                            composite_llvm_type: Type,
1710                            composite_type_name: &str,
1711                            composite_type_unique_id: UniqueTypeId,
1712                            member_descriptions: &[MemberDescription],
1713                            containing_scope: DIScope,
1714
1715                            // Ignore source location information as long as it
1716                            // can't be reconstructed for non-local crates.
1717                            _file_metadata: DIFile,
1718                            _definition_span: Span)
1719                            -> DICompositeType {
1720     // Create the (empty) struct metadata node ...
1721     let composite_type_metadata = create_struct_stub(cx,
1722                                                      composite_llvm_type,
1723                                                      composite_type_name,
1724                                                      composite_type_unique_id,
1725                                                      containing_scope);
1726     // ... and immediately create and add the member descriptions.
1727     set_members_of_composite_type(cx,
1728                                   composite_type_metadata,
1729                                   composite_llvm_type,
1730                                   member_descriptions);
1731
1732     return composite_type_metadata;
1733 }
1734
1735 fn set_members_of_composite_type(cx: &CrateContext,
1736                                  composite_type_metadata: DICompositeType,
1737                                  composite_llvm_type: Type,
1738                                  member_descriptions: &[MemberDescription]) {
1739     // In some rare cases LLVM metadata uniquing would lead to an existing type
1740     // description being used instead of a new one created in
1741     // create_struct_stub. This would cause a hard to trace assertion in
1742     // DICompositeType::SetTypeArray(). The following check makes sure that we
1743     // get a better error message if this should happen again due to some
1744     // regression.
1745     {
1746         let mut composite_types_completed =
1747             debug_context(cx).composite_types_completed.borrow_mut();
1748         if composite_types_completed.contains(&composite_type_metadata) {
1749             cx.sess().bug("debuginfo::set_members_of_composite_type() - \
1750                            Already completed forward declaration re-encountered.");
1751         } else {
1752             composite_types_completed.insert(composite_type_metadata);
1753         }
1754     }
1755
1756     let member_metadata: Vec<DIDescriptor> = member_descriptions
1757         .iter()
1758         .enumerate()
1759         .map(|(i, member_description)| {
1760             let (member_size, member_align) = size_and_align_of(cx, member_description.llvm_type);
1761             let member_offset = match member_description.offset {
1762                 FixedMemberOffset { bytes } => bytes as u64,
1763                 ComputedMemberOffset => machine::llelement_offset(cx, composite_llvm_type, i)
1764             };
1765
1766             let member_name = member_description.name.as_bytes();
1767             let member_name = CString::new(member_name).unwrap();
1768             unsafe {
1769                 llvm::LLVMDIBuilderCreateMemberType(
1770                     DIB(cx),
1771                     composite_type_metadata,
1772                     member_name.as_ptr(),
1773                     NO_FILE_METADATA,
1774                     UNKNOWN_LINE_NUMBER,
1775                     bytes_to_bits(member_size),
1776                     bytes_to_bits(member_align),
1777                     bytes_to_bits(member_offset),
1778                     member_description.flags,
1779                     member_description.type_metadata)
1780             }
1781         })
1782         .collect();
1783
1784     unsafe {
1785         let type_array = create_DIArray(DIB(cx), &member_metadata[..]);
1786         llvm::LLVMDICompositeTypeSetTypeArray(DIB(cx), composite_type_metadata, type_array);
1787     }
1788 }
1789
1790 // A convenience wrapper around LLVMDIBuilderCreateStructType(). Does not do any
1791 // caching, does not add any fields to the struct. This can be done later with
1792 // set_members_of_composite_type().
1793 fn create_struct_stub(cx: &CrateContext,
1794                       struct_llvm_type: Type,
1795                       struct_type_name: &str,
1796                       unique_type_id: UniqueTypeId,
1797                       containing_scope: DIScope)
1798                    -> DICompositeType {
1799     let (struct_size, struct_align) = size_and_align_of(cx, struct_llvm_type);
1800
1801     let unique_type_id_str = debug_context(cx).type_map
1802                                               .borrow()
1803                                               .get_unique_type_id_as_string(unique_type_id);
1804     let name = CString::new(struct_type_name).unwrap();
1805     let unique_type_id = CString::new(unique_type_id_str.as_bytes()).unwrap();
1806     let metadata_stub = unsafe {
1807         // LLVMDIBuilderCreateStructType() wants an empty array. A null
1808         // pointer will lead to hard to trace and debug LLVM assertions
1809         // later on in llvm/lib/IR/Value.cpp.
1810         let empty_array = create_DIArray(DIB(cx), &[]);
1811
1812         llvm::LLVMDIBuilderCreateStructType(
1813             DIB(cx),
1814             containing_scope,
1815             name.as_ptr(),
1816             NO_FILE_METADATA,
1817             UNKNOWN_LINE_NUMBER,
1818             bytes_to_bits(struct_size),
1819             bytes_to_bits(struct_align),
1820             0,
1821             ptr::null_mut(),
1822             empty_array,
1823             0,
1824             ptr::null_mut(),
1825             unique_type_id.as_ptr())
1826     };
1827
1828     return metadata_stub;
1829 }
1830
1831 /// Creates debug information for the given global variable.
1832 ///
1833 /// Adds the created metadata nodes directly to the crate's IR.
1834 pub fn create_global_var_metadata(cx: &CrateContext,
1835                                   node_id: ast::NodeId,
1836                                   global: ValueRef) {
1837     if cx.dbg_cx().is_none() {
1838         return;
1839     }
1840
1841     // Don't create debuginfo for globals inlined from other crates. The other
1842     // crate should already contain debuginfo for it. More importantly, the
1843     // global might not even exist in un-inlined form anywhere which would lead
1844     // to a linker errors.
1845     if cx.external_srcs().borrow().contains_key(&node_id) {
1846         return;
1847     }
1848
1849     let var_item = cx.tcx().map.get(node_id);
1850
1851     let (name, span) = match var_item {
1852         hir_map::NodeItem(item) => {
1853             match item.node {
1854                 hir::ItemStatic(..) => (item.name, item.span),
1855                 hir::ItemConst(..) => (item.name, item.span),
1856                 _ => {
1857                     cx.sess()
1858                       .span_bug(item.span,
1859                                 &format!("debuginfo::\
1860                                          create_global_var_metadata() -
1861                                          Captured var-id refers to \
1862                                          unexpected ast_item variant: {:?}",
1863                                         var_item))
1864                 }
1865             }
1866         },
1867         _ => cx.sess().bug(&format!("debuginfo::create_global_var_metadata() \
1868                                     - Captured var-id refers to unexpected \
1869                                     hir_map variant: {:?}",
1870                                    var_item))
1871     };
1872
1873     let (file_metadata, line_number) = if span != codemap::DUMMY_SP {
1874         let loc = span_start(cx, span);
1875         (file_metadata(cx, &loc.file.name), loc.line as c_uint)
1876     } else {
1877         (NO_FILE_METADATA, UNKNOWN_LINE_NUMBER)
1878     };
1879
1880     let is_local_to_unit = is_node_local_to_unit(cx, node_id);
1881     let variable_type = cx.tcx().node_id_to_type(node_id);
1882     let type_metadata = type_metadata(cx, variable_type, span);
1883     let node_def_id = cx.tcx().map.local_def_id(node_id);
1884     let namespace_node = namespace_for_item(cx, node_def_id);
1885     let var_name = name.to_string();
1886     let linkage_name =
1887         namespace_node.mangled_name_of_contained_item(&var_name[..]);
1888     let var_scope = namespace_node.scope;
1889
1890     let var_name = CString::new(var_name).unwrap();
1891     let linkage_name = CString::new(linkage_name).unwrap();
1892     unsafe {
1893         llvm::LLVMDIBuilderCreateStaticVariable(DIB(cx),
1894                                                 var_scope,
1895                                                 var_name.as_ptr(),
1896                                                 linkage_name.as_ptr(),
1897                                                 file_metadata,
1898                                                 line_number,
1899                                                 type_metadata,
1900                                                 is_local_to_unit,
1901                                                 global,
1902                                                 ptr::null_mut());
1903     }
1904 }
1905
1906 /// Creates debug information for the given local variable.
1907 ///
1908 /// This function assumes that there's a datum for each pattern component of the
1909 /// local in `bcx.fcx.lllocals`.
1910 /// Adds the created metadata nodes directly to the crate's IR.
1911 pub fn create_local_var_metadata(bcx: Block, local: &hir::Local) {
1912     if bcx.unreachable.get() ||
1913        fn_should_be_ignored(bcx.fcx) ||
1914        bcx.sess().opts.debuginfo != FullDebugInfo  {
1915         return;
1916     }
1917
1918     let cx = bcx.ccx();
1919     let def_map = &cx.tcx().def_map;
1920     let locals = bcx.fcx.lllocals.borrow();
1921
1922     pat_util::pat_bindings(def_map, &local.pat, |_, node_id, span, var_name| {
1923         let datum = match locals.get(&node_id) {
1924             Some(datum) => datum,
1925             None => {
1926                 bcx.sess().span_bug(span,
1927                     &format!("no entry in lllocals table for {}",
1928                             node_id));
1929             }
1930         };
1931
1932         if unsafe { llvm::LLVMIsAAllocaInst(datum.val) } == ptr::null_mut() {
1933             cx.sess().span_bug(span, "debuginfo::create_local_var_metadata() - \
1934                                       Referenced variable location is not an alloca!");
1935         }
1936
1937         let scope_metadata = scope_metadata(bcx.fcx, node_id, span);
1938
1939         declare_local(bcx,
1940                       var_name.node,
1941                       datum.ty,
1942                       scope_metadata,
1943                       VariableAccess::DirectVariable { alloca: datum.val },
1944                       VariableKind::LocalVariable,
1945                       span);
1946     })
1947 }
1948
1949 /// Creates debug information for a variable captured in a closure.
1950 ///
1951 /// Adds the created metadata nodes directly to the crate's IR.
1952 pub fn create_captured_var_metadata<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1953                                                 node_id: ast::NodeId,
1954                                                 env_pointer: ValueRef,
1955                                                 env_index: usize,
1956                                                 captured_by_ref: bool,
1957                                                 span: Span) {
1958     if bcx.unreachable.get() ||
1959        fn_should_be_ignored(bcx.fcx) ||
1960        bcx.sess().opts.debuginfo != FullDebugInfo {
1961         return;
1962     }
1963
1964     let cx = bcx.ccx();
1965
1966     let ast_item = cx.tcx().map.find(node_id);
1967
1968     let variable_name = match ast_item {
1969         None => {
1970             cx.sess().span_bug(span, "debuginfo::create_captured_var_metadata: node not found");
1971         }
1972         Some(hir_map::NodeLocal(pat)) => {
1973             match pat.node {
1974                 PatKind::Ident(_, ref path1, _) => {
1975                     path1.node.name
1976                 }
1977                 _ => {
1978                     cx.sess()
1979                       .span_bug(span,
1980                                 &format!(
1981                                 "debuginfo::create_captured_var_metadata() - \
1982                                  Captured var-id refers to unexpected \
1983                                  hir_map variant: {:?}",
1984                                  ast_item));
1985                 }
1986             }
1987         }
1988         _ => {
1989             cx.sess()
1990               .span_bug(span,
1991                         &format!("debuginfo::create_captured_var_metadata() - \
1992                                  Captured var-id refers to unexpected \
1993                                  hir_map variant: {:?}",
1994                                 ast_item));
1995         }
1996     };
1997
1998     let variable_type = common::node_id_type(bcx, node_id);
1999     let scope_metadata = bcx.fcx.debug_context.get_ref(cx, span).fn_metadata;
2000
2001     // env_pointer is the alloca containing the pointer to the environment,
2002     // so it's type is **EnvironmentType. In order to find out the type of
2003     // the environment we have to "dereference" two times.
2004     let llvm_env_data_type = common::val_ty(env_pointer).element_type()
2005                                                         .element_type();
2006     let byte_offset_of_var_in_env = machine::llelement_offset(cx,
2007                                                               llvm_env_data_type,
2008                                                               env_index);
2009
2010     let address_operations = unsafe {
2011         [llvm::LLVMDIBuilderCreateOpDeref(),
2012          llvm::LLVMDIBuilderCreateOpPlus(),
2013          byte_offset_of_var_in_env as i64,
2014          llvm::LLVMDIBuilderCreateOpDeref()]
2015     };
2016
2017     let address_op_count = if captured_by_ref {
2018         address_operations.len()
2019     } else {
2020         address_operations.len() - 1
2021     };
2022
2023     let variable_access = VariableAccess::IndirectVariable {
2024         alloca: env_pointer,
2025         address_operations: &address_operations[..address_op_count]
2026     };
2027
2028     declare_local(bcx,
2029                   variable_name,
2030                   variable_type,
2031                   scope_metadata,
2032                   variable_access,
2033                   VariableKind::CapturedVariable,
2034                   span);
2035 }
2036
2037 /// Creates debug information for a local variable introduced in the head of a
2038 /// match-statement arm.
2039 ///
2040 /// Adds the created metadata nodes directly to the crate's IR.
2041 pub fn create_match_binding_metadata<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
2042                                                  variable_name: ast::Name,
2043                                                  binding: BindingInfo<'tcx>) {
2044     if bcx.unreachable.get() ||
2045        fn_should_be_ignored(bcx.fcx) ||
2046        bcx.sess().opts.debuginfo != FullDebugInfo {
2047         return;
2048     }
2049
2050     let scope_metadata = scope_metadata(bcx.fcx, binding.id, binding.span);
2051     let aops = unsafe {
2052         [llvm::LLVMDIBuilderCreateOpDeref()]
2053     };
2054     // Regardless of the actual type (`T`) we're always passed the stack slot
2055     // (alloca) for the binding. For ByRef bindings that's a `T*` but for ByMove
2056     // bindings we actually have `T**`. So to get the actual variable we need to
2057     // dereference once more. For ByCopy we just use the stack slot we created
2058     // for the binding.
2059     let var_access = match binding.trmode {
2060         TransBindingMode::TrByCopy(llbinding) |
2061         TransBindingMode::TrByMoveIntoCopy(llbinding) => VariableAccess::DirectVariable {
2062             alloca: llbinding
2063         },
2064         TransBindingMode::TrByMoveRef => VariableAccess::IndirectVariable {
2065             alloca: binding.llmatch,
2066             address_operations: &aops
2067         },
2068         TransBindingMode::TrByRef => VariableAccess::DirectVariable {
2069             alloca: binding.llmatch
2070         }
2071     };
2072
2073     declare_local(bcx,
2074                   variable_name,
2075                   binding.ty,
2076                   scope_metadata,
2077                   var_access,
2078                   VariableKind::LocalVariable,
2079                   binding.span);
2080 }
2081
2082 /// Creates debug information for the given function argument.
2083 ///
2084 /// This function assumes that there's a datum for each pattern component of the
2085 /// argument in `bcx.fcx.lllocals`.
2086 /// Adds the created metadata nodes directly to the crate's IR.
2087 pub fn create_argument_metadata(bcx: Block, arg: &hir::Arg) {
2088     if bcx.unreachable.get() ||
2089        fn_should_be_ignored(bcx.fcx) ||
2090        bcx.sess().opts.debuginfo != FullDebugInfo {
2091         return;
2092     }
2093
2094     let def_map = &bcx.tcx().def_map;
2095     let scope_metadata = bcx
2096                          .fcx
2097                          .debug_context
2098                          .get_ref(bcx.ccx(), arg.pat.span)
2099                          .fn_metadata;
2100     let locals = bcx.fcx.lllocals.borrow();
2101
2102     pat_util::pat_bindings(def_map, &arg.pat, |_, node_id, span, var_name| {
2103         let datum = match locals.get(&node_id) {
2104             Some(v) => v,
2105             None => {
2106                 bcx.sess().span_bug(span,
2107                     &format!("no entry in lllocals table for {}",
2108                             node_id));
2109             }
2110         };
2111
2112         if unsafe { llvm::LLVMIsAAllocaInst(datum.val) } == ptr::null_mut() {
2113             bcx.sess().span_bug(span, "debuginfo::create_argument_metadata() - \
2114                                        Referenced variable location is not an alloca!");
2115         }
2116
2117         let argument_index = {
2118             let counter = &bcx
2119                           .fcx
2120                           .debug_context
2121                           .get_ref(bcx.ccx(), span)
2122                           .argument_counter;
2123             let argument_index = counter.get();
2124             counter.set(argument_index + 1);
2125             argument_index
2126         };
2127
2128         declare_local(bcx,
2129                       var_name.node,
2130                       datum.ty,
2131                       scope_metadata,
2132                       VariableAccess::DirectVariable { alloca: datum.val },
2133                       VariableKind::ArgumentVariable(argument_index),
2134                       span);
2135     })
2136 }