src/librustc_trans/trans_item.rs

   1 // Copyright 2016 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 //! Walks the crate looking for items/impl-items/trait-items that have
  12 //! either a `rustc_symbol_name` or `rustc_item_path` attribute and
  13 //! generates an error giving, respectively, the symbol name or
  14 //! item-path. This is used for unit testing the code that generates
  15 //! paths etc in all kinds of annoying scenarios.
  16
  17 use asm;
  18 use attributes;
  19 use base;
  20 use consts;
  21 use context::CrateContext;
  22 use common;
  23 use declare;
  24 use llvm;
  25 use monomorphize::Instance;
  26 use rustc::dep_graph::DepNode;
  27 use rustc::hir;
  28 use rustc::hir::def_id::DefId;
  29 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
  30 use rustc::ty::subst::Substs;
  31 use syntax::ast::{self, NodeId};
  32 use syntax::attr;
  33 use syntax_pos::Span;
  34 use syntax_pos::symbol::Symbol;
  35 use type_of;
  36 use std::fmt::Write;
  37 use std::iter;
  38
  39 #[derive(PartialEq, Eq, Clone, Copy, Debug, Hash)]
  40 pub enum TransItem<'tcx> {
  41     Fn(Instance<'tcx>),
  42     Static(NodeId),
  43     GlobalAsm(NodeId),
  44 }
  45
  46 /// Describes how a translation item will be instantiated in object files.
  47 #[derive(PartialEq, Eq, Clone, Copy, Debug, Hash)]
  48 pub enum InstantiationMode {
  49     /// There will be exactly one instance of the given TransItem. It will have
  50     /// external linkage so that it can be linked to from other codegen units.
  51     GloballyShared,
  52
  53     /// Each codegen unit containing a reference to the given TransItem will
  54     /// have its own private copy of the function (with internal linkage).
  55     LocalCopy,
  56 }
  57
  58 impl<'a, 'tcx> TransItem<'tcx> {
  59
  60     pub fn define(&self, ccx: &CrateContext<'a, 'tcx>) {
  61         debug!("BEGIN IMPLEMENTING '{} ({})' in cgu {}",
  62                   self.to_string(ccx.tcx()),
  63                   self.to_raw_string(),
  64                   ccx.codegen_unit().name());
  65
  66         // (*) This code executes in the context of a dep-node for the
  67         // entire CGU. In some cases, we introduce dep-nodes for
  68         // particular items that we are translating (these nodes will
  69         // have read edges coming into the CGU node). These smaller
  70         // nodes are not needed for correctness -- we always
  71         // invalidate an entire CGU at a time -- but they enable
  72         // finer-grained testing, since you can write tests that check
  73         // that the incoming edges to a particular fn are from a
  74         // particular set.
  75
  76         match *self {
  77             TransItem::Static(node_id) => {
  78                 let def_id = ccx.tcx().hir.local_def_id(node_id);
  79                 let _task = ccx.tcx().dep_graph.in_task(DepNode::TransCrateItem(def_id)); // (*)
  80                 let item = ccx.tcx().hir.expect_item(node_id);
  81                 if let hir::ItemStatic(_, m, _) = item.node {
  82                     match consts::trans_static(&ccx, m, item.id, &item.attrs) {
  83                         Ok(_) => { /* Cool, everything's alright. */ },
  84                         Err(err) => {
  85                             err.report(ccx.tcx(), item.span, "static");
  86                         }
  87                     };
  88                 } else {
  89                     span_bug!(item.span, "Mismatch between hir::Item type and TransItem type")
  90                 }
  91             }
  92             TransItem::GlobalAsm(node_id) => {
  93                 let item = ccx.tcx().hir.expect_item(node_id);
  94                 if let hir::ItemGlobalAsm(ref ga) = item.node {
  95                     asm::trans_global_asm(ccx, ga);
  96                 } else {
  97                     span_bug!(item.span, "Mismatch between hir::Item type and TransItem type")
  98                 }
  99             }
 100             TransItem::Fn(instance) => {
 101                 let _task = ccx.tcx().dep_graph.in_task(
 102                     DepNode::TransCrateItem(instance.def_id())); // (*)
 103
 104                 base::trans_instance(&ccx, instance);
 105             }
 106         }
 107
 108         debug!("END IMPLEMENTING '{} ({})' in cgu {}",
 109                self.to_string(ccx.tcx()),
 110                self.to_raw_string(),
 111                ccx.codegen_unit().name());
 112     }
 113
 114     pub fn predefine(&self,
 115                      ccx: &CrateContext<'a, 'tcx>,
 116                      linkage: llvm::Linkage) {
 117         debug!("BEGIN PREDEFINING '{} ({})' in cgu {}",
 118                self.to_string(ccx.tcx()),
 119                self.to_raw_string(),
 120                ccx.codegen_unit().name());
 121
 122         let symbol_name = self.symbol_name(ccx.tcx());
 123
 124         debug!("symbol {}", &symbol_name);
 125
 126         match *self {
 127             TransItem::Static(node_id) => {
 128                 TransItem::predefine_static(ccx, node_id, linkage, &symbol_name);
 129             }
 130             TransItem::Fn(instance) => {
 131                 TransItem::predefine_fn(ccx, instance, linkage, &symbol_name);
 132             }
 133             TransItem::GlobalAsm(..) => {}
 134         }
 135
 136         debug!("END PREDEFINING '{} ({})' in cgu {}",
 137                self.to_string(ccx.tcx()),
 138                self.to_raw_string(),
 139                ccx.codegen_unit().name());
 140     }
 141
 142     fn predefine_static(ccx: &CrateContext<'a, 'tcx>,
 143                         node_id: ast::NodeId,
 144                         linkage: llvm::Linkage,
 145                         symbol_name: &str) {
 146         let def_id = ccx.tcx().hir.local_def_id(node_id);
 147         let instance = Instance::mono(ccx.tcx(), def_id);
 148         let ty = common::instance_ty(ccx.shared(), &instance);
 149         let llty = type_of::type_of(ccx, ty);
 150
 151         let g = declare::define_global(ccx, symbol_name, llty).unwrap_or_else(|| {
 152             ccx.sess().span_fatal(ccx.tcx().hir.span(node_id),
 153                 &format!("symbol `{}` is already defined", symbol_name))
 154         });
 155
 156         unsafe { llvm::LLVMRustSetLinkage(g, linkage) };
 157
 158         ccx.instances().borrow_mut().insert(instance, g);
 159         ccx.statics().borrow_mut().insert(g, def_id);
 160     }
 161
 162     fn predefine_fn(ccx: &CrateContext<'a, 'tcx>,
 163                     instance: Instance<'tcx>,
 164                     linkage: llvm::Linkage,
 165                     symbol_name: &str) {
 166         assert!(!instance.substs.needs_infer() &&
 167                 !instance.substs.has_param_types());
 168
 169         let mono_ty = common::instance_ty(ccx.shared(), &instance);
 170         let attrs = instance.def.attrs(ccx.tcx());
 171         let lldecl = declare::declare_fn(ccx, symbol_name, mono_ty);
 172         unsafe { llvm::LLVMRustSetLinkage(lldecl, linkage) };
 173         base::set_link_section(ccx, lldecl, &attrs);
 174         if linkage == llvm::Linkage::LinkOnceODRLinkage ||
 175             linkage == llvm::Linkage::WeakODRLinkage {
 176             llvm::SetUniqueComdat(ccx.llmod(), lldecl);
 177         }
 178
 179         debug!("predefine_fn: mono_ty = {:?} instance = {:?}", mono_ty, instance);
 180         if common::is_inline_instance(ccx.tcx(), &instance) {
 181             attributes::inline(lldecl, attributes::InlineAttr::Hint);
 182         }
 183         attributes::from_fn_attrs(ccx, &attrs, lldecl);
 184
 185         ccx.instances().borrow_mut().insert(instance, lldecl);
 186     }
 187
 188     pub fn symbol_name(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> ty::SymbolName {
 189         match *self {
 190             TransItem::Fn(instance) => tcx.symbol_name(instance),
 191             TransItem::Static(node_id) => {
 192                 let def_id = tcx.hir.local_def_id(node_id);
 193                 tcx.symbol_name(Instance::mono(tcx, def_id))
 194             }
 195             TransItem::GlobalAsm(node_id) => {
 196                 let def_id = tcx.hir.local_def_id(node_id);
 197                 ty::SymbolName {
 198                     name: Symbol::intern(&format!("global_asm_{:?}", def_id)).as_str()
 199                 }
 200             }
 201         }
 202     }
 203
 204     pub fn local_span(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Option<Span> {
 205         match *self {
 206             TransItem::Fn(Instance { def, .. }) => {
 207                 tcx.hir.as_local_node_id(def.def_id())
 208             }
 209             TransItem::Static(node_id) |
 210             TransItem::GlobalAsm(node_id) => {
 211                 Some(node_id)
 212             }
 213         }.map(|node_id| tcx.hir.span(node_id))
 214     }
 215
 216     pub fn instantiation_mode(&self,
 217                               tcx: TyCtxt<'a, 'tcx, 'tcx>)
 218                               -> InstantiationMode {
 219         match *self {
 220             TransItem::Fn(ref instance) => {
 221                 if self.explicit_linkage(tcx).is_none() &&
 222                     common::requests_inline(tcx, instance)
 223                 {
 224                     InstantiationMode::LocalCopy
 225                 } else {
 226                     InstantiationMode::GloballyShared
 227                 }
 228             }
 229             TransItem::Static(..) => InstantiationMode::GloballyShared,
 230             TransItem::GlobalAsm(..) => InstantiationMode::GloballyShared,
 231         }
 232     }
 233
 234     pub fn is_generic_fn(&self) -> bool {
 235         match *self {
 236             TransItem::Fn(ref instance) => {
 237                 instance.substs.types().next().is_some()
 238             }
 239             TransItem::Static(..) |
 240             TransItem::GlobalAsm(..) => false,
 241         }
 242     }
 243
 244     pub fn explicit_linkage(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> Option<llvm::Linkage> {
 245         let def_id = match *self {
 246             TransItem::Fn(ref instance) => instance.def_id(),
 247             TransItem::Static(node_id) => tcx.hir.local_def_id(node_id),
 248             TransItem::GlobalAsm(..) => return None,
 249         };
 250
 251         let attributes = tcx.get_attrs(def_id);
 252         if let Some(name) = attr::first_attr_value_str_by_name(&attributes, "linkage") {
 253             if let Some(linkage) = base::llvm_linkage_by_name(&name.as_str()) {
 254                 Some(linkage)
 255             } else {
 256                 let span = tcx.hir.span_if_local(def_id);
 257                 if let Some(span) = span {
 258                     tcx.sess.span_fatal(span, "invalid linkage specified")
 259                 } else {
 260                     tcx.sess.fatal(&format!("invalid linkage specified: {}", name))
 261                 }
 262             }
 263         } else {
 264             None
 265         }
 266     }
 267
 268     pub fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
 269         let hir_map = &tcx.hir;
 270
 271         return match *self {
 272             TransItem::Fn(instance) => {
 273                 to_string_internal(tcx, "fn ", instance)
 274             },
 275             TransItem::Static(node_id) => {
 276                 let def_id = hir_map.local_def_id(node_id);
 277                 let instance = Instance::new(def_id, tcx.intern_substs(&[]));
 278                 to_string_internal(tcx, "static ", instance)
 279             },
 280             TransItem::GlobalAsm(..) => {
 281                 "global_asm".to_string()
 282             }
 283         };
 284
 285         fn to_string_internal<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 286                                         prefix: &str,
 287                                         instance: Instance<'tcx>)
 288                                         -> String {
 289             let mut result = String::with_capacity(32);
 290             result.push_str(prefix);
 291             let printer = DefPathBasedNames::new(tcx, false, false);
 292             printer.push_instance_as_string(instance, &mut result);
 293             result
 294         }
 295     }
 296
 297     pub fn to_raw_string(&self) -> String {
 298         match *self {
 299             TransItem::Fn(instance) => {
 300                 format!("Fn({:?}, {})",
 301                          instance.def,
 302                          instance.substs.as_ptr() as usize)
 303             }
 304             TransItem::Static(id) => {
 305                 format!("Static({:?})", id)
 306             }
 307             TransItem::GlobalAsm(id) => {
 308                 format!("GlobalAsm({:?})", id)
 309             }
 310         }
 311     }
 312 }
 313
 314
 315 //=-----------------------------------------------------------------------------
 316 // TransItem String Keys
 317 //=-----------------------------------------------------------------------------
 318
 319 // The code below allows for producing a unique string key for a trans item.
 320 // These keys are used by the handwritten auto-tests, so they need to be
 321 // predictable and human-readable.
 322 //
 323 // Note: A lot of this could looks very similar to what's already in the
 324 //       ppaux module. It would be good to refactor things so we only have one
 325 //       parameterizable implementation for printing types.
 326
 327 /// Same as `unique_type_name()` but with the result pushed onto the given
 328 /// `output` parameter.
 329 pub struct DefPathBasedNames<'a, 'tcx: 'a> {
 330     tcx: TyCtxt<'a, 'tcx, 'tcx>,
 331     omit_disambiguators: bool,
 332     omit_local_crate_name: bool,
 333 }
 334
 335 impl<'a, 'tcx> DefPathBasedNames<'a, 'tcx> {
 336     pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 337                omit_disambiguators: bool,
 338                omit_local_crate_name: bool)
 339                -> Self {
 340         DefPathBasedNames {
 341             tcx: tcx,
 342             omit_disambiguators: omit_disambiguators,
 343             omit_local_crate_name: omit_local_crate_name,
 344         }
 345     }
 346
 347     pub fn push_type_name(&self, t: Ty<'tcx>, output: &mut String) {
 348         match t.sty {
 349             ty::TyBool              => output.push_str("bool"),
 350             ty::TyChar              => output.push_str("char"),
 351             ty::TyStr               => output.push_str("str"),
 352             ty::TyNever             => output.push_str("!"),
 353             ty::TyInt(ast::IntTy::Is)    => output.push_str("isize"),
 354             ty::TyInt(ast::IntTy::I8)    => output.push_str("i8"),
 355             ty::TyInt(ast::IntTy::I16)   => output.push_str("i16"),
 356             ty::TyInt(ast::IntTy::I32)   => output.push_str("i32"),
 357             ty::TyInt(ast::IntTy::I64)   => output.push_str("i64"),
 358             ty::TyInt(ast::IntTy::I128)   => output.push_str("i128"),
 359             ty::TyUint(ast::UintTy::Us)   => output.push_str("usize"),
 360             ty::TyUint(ast::UintTy::U8)   => output.push_str("u8"),
 361             ty::TyUint(ast::UintTy::U16)  => output.push_str("u16"),
 362             ty::TyUint(ast::UintTy::U32)  => output.push_str("u32"),
 363             ty::TyUint(ast::UintTy::U64)  => output.push_str("u64"),
 364             ty::TyUint(ast::UintTy::U128)  => output.push_str("u128"),
 365             ty::TyFloat(ast::FloatTy::F32) => output.push_str("f32"),
 366             ty::TyFloat(ast::FloatTy::F64) => output.push_str("f64"),
 367             ty::TyAdt(adt_def, substs) => {
 368                 self.push_def_path(adt_def.did, output);
 369                 self.push_type_params(substs, iter::empty(), output);
 370             },
 371             ty::TyTuple(component_types, _) => {
 372                 output.push('(');
 373                 for &component_type in component_types {
 374                     self.push_type_name(component_type, output);
 375                     output.push_str(", ");
 376                 }
 377                 if !component_types.is_empty() {
 378                     output.pop();
 379                     output.pop();
 380                 }
 381                 output.push(')');
 382             },
 383             ty::TyRawPtr(ty::TypeAndMut { ty: inner_type, mutbl } ) => {
 384                 output.push('*');
 385                 match mutbl {
 386                     hir::MutImmutable => output.push_str("const "),
 387                     hir::MutMutable => output.push_str("mut "),
 388                 }
 389
 390                 self.push_type_name(inner_type, output);
 391             },
 392             ty::TyRef(_, ty::TypeAndMut { ty: inner_type, mutbl }) => {
 393                 output.push('&');
 394                 if mutbl == hir::MutMutable {
 395                     output.push_str("mut ");
 396                 }
 397
 398                 self.push_type_name(inner_type, output);
 399             },
 400             ty::TyArray(inner_type, len) => {
 401                 output.push('[');
 402                 self.push_type_name(inner_type, output);
 403                 write!(output, "; {}", len).unwrap();
 404                 output.push(']');
 405             },
 406             ty::TySlice(inner_type) => {
 407                 output.push('[');
 408                 self.push_type_name(inner_type, output);
 409                 output.push(']');
 410             },
 411             ty::TyDynamic(ref trait_data, ..) => {
 412                 if let Some(principal) = trait_data.principal() {
 413                     self.push_def_path(principal.def_id(), output);
 414                     self.push_type_params(principal.skip_binder().substs,
 415                         trait_data.projection_bounds(),
 416                         output);
 417                 }
 418             },
 419             ty::TyFnDef(.., sig) |
 420             ty::TyFnPtr(sig) => {
 421                 if sig.unsafety() == hir::Unsafety::Unsafe {
 422                     output.push_str("unsafe ");
 423                 }
 424
 425                 let abi = sig.abi();
 426                 if abi != ::abi::Abi::Rust {
 427                     output.push_str("extern \"");
 428                     output.push_str(abi.name());
 429                     output.push_str("\" ");
 430                 }
 431
 432                 output.push_str("fn(");
 433
 434                 let sig = self.tcx.erase_late_bound_regions_and_normalize(&sig);
 435
 436                 if !sig.inputs().is_empty() {
 437                     for &parameter_type in sig.inputs() {
 438                         self.push_type_name(parameter_type, output);
 439                         output.push_str(", ");
 440                     }
 441                     output.pop();
 442                     output.pop();
 443                 }
 444
 445                 if sig.variadic {
 446                     if !sig.inputs().is_empty() {
 447                         output.push_str(", ...");
 448                     } else {
 449                         output.push_str("...");
 450                     }
 451                 }
 452
 453                 output.push(')');
 454
 455                 if !sig.output().is_nil() {
 456                     output.push_str(" -> ");
 457                     self.push_type_name(sig.output(), output);
 458                 }
 459             },
 460             ty::TyClosure(def_id, ref closure_substs) => {
 461                 self.push_def_path(def_id, output);
 462                 let generics = self.tcx.generics_of(self.tcx.closure_base_def_id(def_id));
 463                 let substs = closure_substs.substs.truncate_to(self.tcx, generics);
 464                 self.push_type_params(substs, iter::empty(), output);
 465             }
 466             ty::TyError |
 467             ty::TyInfer(_) |
 468             ty::TyProjection(..) |
 469             ty::TyParam(_) |
 470             ty::TyAnon(..) => {
 471                 bug!("DefPathBasedNames: Trying to create type name for \
 472                                          unexpected type: {:?}", t);
 473             }
 474         }
 475     }
 476
 477     pub fn push_def_path(&self,
 478                          def_id: DefId,
 479                          output: &mut String) {
 480         let def_path = self.tcx.def_path(def_id);
 481
 482         // some_crate::
 483         if !(self.omit_local_crate_name && def_id.is_local()) {
 484             output.push_str(&self.tcx.crate_name(def_path.krate).as_str());
 485             output.push_str("::");
 486         }
 487
 488         // foo::bar::ItemName::
 489         for part in self.tcx.def_path(def_id).data {
 490             if self.omit_disambiguators {
 491                 write!(output, "{}::", part.data.as_interned_str()).unwrap();
 492             } else {
 493                 write!(output, "{}[{}]::",
 494                        part.data.as_interned_str(),
 495                        part.disambiguator).unwrap();
 496             }
 497         }
 498
 499         // remove final "::"
 500         output.pop();
 501         output.pop();
 502     }
 503
 504     fn push_type_params<I>(&self,
 505                             substs: &Substs<'tcx>,
 506                             projections: I,
 507                             output: &mut String)
 508         where I: Iterator<Item=ty::PolyExistentialProjection<'tcx>>
 509     {
 510         let mut projections = projections.peekable();
 511         if substs.types().next().is_none() && projections.peek().is_none() {
 512             return;
 513         }
 514
 515         output.push('<');
 516
 517         for type_parameter in substs.types() {
 518             self.push_type_name(type_parameter, output);
 519             output.push_str(", ");
 520         }
 521
 522         for projection in projections {
 523             let projection = projection.skip_binder();
 524             let name = &projection.item_name.as_str();
 525             output.push_str(name);
 526             output.push_str("=");
 527             self.push_type_name(projection.ty, output);
 528             output.push_str(", ");
 529         }
 530
 531         output.pop();
 532         output.pop();
 533
 534         output.push('>');
 535     }
 536
 537     pub fn push_instance_as_string(&self,
 538                                    instance: Instance<'tcx>,
 539                                    output: &mut String) {
 540         self.push_def_path(instance.def_id(), output);
 541         self.push_type_params(instance.substs, iter::empty(), output);
 542     }
 543 }