src/librustc_trans/trans/context.rs

   1 // Copyright 2013 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 llvm;
  12 use llvm::{ContextRef, ModuleRef, ValueRef, BuilderRef};
  13 use metadata::common::LinkMeta;
  14 use middle::def::ExportMap;
  15 use middle::traits;
  16 use trans::adt;
  17 use trans::base;
  18 use trans::builder::Builder;
  19 use trans::common::{ExternMap,BuilderRef_res};
  20 use trans::debuginfo;
  21 use trans::declare;
  22 use trans::glue::DropGlueKind;
  23 use trans::monomorphize::MonoId;
  24 use trans::type_::{Type, TypeNames};
  25 use middle::subst::Substs;
  26 use middle::ty::{self, Ty};
  27 use session::config::NoDebugInfo;
  28 use session::Session;
  29 use util::sha2::Sha256;
  30 use util::nodemap::{NodeMap, NodeSet, DefIdMap, FnvHashMap, FnvHashSet};
  31
  32 use std::ffi::CString;
  33 use std::cell::{Cell, RefCell};
  34 use std::ptr;
  35 use std::rc::Rc;
  36 use syntax::ast;
  37 use syntax::parse::token::InternedString;
  38
  39 pub struct Stats {
  40     pub n_glues_created: Cell<usize>,
  41     pub n_null_glues: Cell<usize>,
  42     pub n_real_glues: Cell<usize>,
  43     pub n_fns: Cell<usize>,
  44     pub n_monos: Cell<usize>,
  45     pub n_inlines: Cell<usize>,
  46     pub n_closures: Cell<usize>,
  47     pub n_llvm_insns: Cell<usize>,
  48     pub llvm_insns: RefCell<FnvHashMap<String, usize>>,
  49     // (ident, llvm-instructions)
  50     pub fn_stats: RefCell<Vec<(String, usize)> >,
  51 }
  52
  53 /// The shared portion of a `CrateContext`.  There is one `SharedCrateContext`
  54 /// per crate.  The data here is shared between all compilation units of the
  55 /// crate, so it must not contain references to any LLVM data structures
  56 /// (aside from metadata-related ones).
  57 pub struct SharedCrateContext<'a, 'tcx: 'a> {
  58     local_ccxs: Vec<LocalCrateContext<'tcx>>,
  59
  60     metadata_llmod: ModuleRef,
  61     metadata_llcx: ContextRef,
  62
  63     export_map: ExportMap,
  64     reachable: NodeSet,
  65     item_symbols: RefCell<NodeMap<String>>,
  66     link_meta: LinkMeta,
  67     symbol_hasher: RefCell<Sha256>,
  68     tcx: &'a ty::ctxt<'tcx>,
  69     stats: Stats,
  70     check_overflow: bool,
  71     check_drop_flag_for_sanity: bool,
  72
  73     available_drop_glues: RefCell<FnvHashMap<DropGlueKind<'tcx>, String>>,
  74     use_dll_storage_attrs: bool,
  75 }
  76
  77 /// The local portion of a `CrateContext`.  There is one `LocalCrateContext`
  78 /// per compilation unit.  Each one has its own LLVM `ContextRef` so that
  79 /// several compilation units may be optimized in parallel.  All other LLVM
  80 /// data structures in the `LocalCrateContext` are tied to that `ContextRef`.
  81 pub struct LocalCrateContext<'tcx> {
  82     llmod: ModuleRef,
  83     llcx: ContextRef,
  84     tn: TypeNames,
  85     externs: RefCell<ExternMap>,
  86     item_vals: RefCell<NodeMap<ValueRef>>,
  87     needs_unwind_cleanup_cache: RefCell<FnvHashMap<Ty<'tcx>, bool>>,
  88     fn_pointer_shims: RefCell<FnvHashMap<Ty<'tcx>, ValueRef>>,
  89     drop_glues: RefCell<FnvHashMap<DropGlueKind<'tcx>, ValueRef>>,
  90     /// Track mapping of external ids to local items imported for inlining
  91     external: RefCell<DefIdMap<Option<ast::NodeId>>>,
  92     /// Backwards version of the `external` map (inlined items to where they
  93     /// came from)
  94     external_srcs: RefCell<NodeMap<ast::DefId>>,
  95     /// Cache instances of monomorphized functions
  96     monomorphized: RefCell<FnvHashMap<MonoId<'tcx>, ValueRef>>,
  97     monomorphizing: RefCell<DefIdMap<usize>>,
  98     available_monomorphizations: RefCell<FnvHashSet<String>>,
  99     /// Cache generated vtables
 100     vtables: RefCell<FnvHashMap<ty::PolyTraitRef<'tcx>, ValueRef>>,
 101     /// Cache of constant strings,
 102     const_cstr_cache: RefCell<FnvHashMap<InternedString, ValueRef>>,
 103
 104     /// Reverse-direction for const ptrs cast from globals.
 105     /// Key is a ValueRef holding a *T,
 106     /// Val is a ValueRef holding a *[T].
 107     ///
 108     /// Needed because LLVM loses pointer->pointee association
 109     /// when we ptrcast, and we have to ptrcast during translation
 110     /// of a [T] const because we form a slice, a (*T,usize) pair, not
 111     /// a pointer to an LLVM array type. Similar for trait objects.
 112     const_unsized: RefCell<FnvHashMap<ValueRef, ValueRef>>,
 113
 114     /// Cache of emitted const globals (value -> global)
 115     const_globals: RefCell<FnvHashMap<ValueRef, ValueRef>>,
 116
 117     /// Cache of emitted const values
 118     const_values: RefCell<FnvHashMap<(ast::NodeId, &'tcx Substs<'tcx>), ValueRef>>,
 119
 120     /// Cache of external const values
 121     extern_const_values: RefCell<DefIdMap<ValueRef>>,
 122
 123     impl_method_cache: RefCell<FnvHashMap<(ast::DefId, ast::Name), ast::DefId>>,
 124
 125     /// Cache of closure wrappers for bare fn's.
 126     closure_bare_wrapper_cache: RefCell<FnvHashMap<ValueRef, ValueRef>>,
 127
 128     /// List of globals for static variables which need to be passed to the
 129     /// LLVM function ReplaceAllUsesWith (RAUW) when translation is complete.
 130     /// (We have to make sure we don't invalidate any ValueRefs referring
 131     /// to constants.)
 132     statics_to_rauw: RefCell<Vec<(ValueRef, ValueRef)>>,
 133
 134     lltypes: RefCell<FnvHashMap<Ty<'tcx>, Type>>,
 135     llsizingtypes: RefCell<FnvHashMap<Ty<'tcx>, Type>>,
 136     adt_reprs: RefCell<FnvHashMap<Ty<'tcx>, Rc<adt::Repr<'tcx>>>>,
 137     type_hashcodes: RefCell<FnvHashMap<Ty<'tcx>, String>>,
 138     int_type: Type,
 139     opaque_vec_type: Type,
 140     builder: BuilderRef_res,
 141
 142     /// Holds the LLVM values for closure IDs.
 143     closure_vals: RefCell<FnvHashMap<MonoId<'tcx>, ValueRef>>,
 144
 145     dbg_cx: Option<debuginfo::CrateDebugContext<'tcx>>,
 146
 147     eh_personality: RefCell<Option<ValueRef>>,
 148     rust_try_fn: RefCell<Option<ValueRef>>,
 149     unwind_resume_hooked: Cell<bool>,
 150
 151     intrinsics: RefCell<FnvHashMap<&'static str, ValueRef>>,
 152
 153     /// Number of LLVM instructions translated into this `LocalCrateContext`.
 154     /// This is used to perform some basic load-balancing to keep all LLVM
 155     /// contexts around the same size.
 156     n_llvm_insns: Cell<usize>,
 157
 158     trait_cache: RefCell<FnvHashMap<ty::PolyTraitRef<'tcx>,
 159                                     traits::Vtable<'tcx, ()>>>,
 160 }
 161
 162 pub struct CrateContext<'a, 'tcx: 'a> {
 163     shared: &'a SharedCrateContext<'a, 'tcx>,
 164     local: &'a LocalCrateContext<'tcx>,
 165     /// The index of `local` in `shared.local_ccxs`.  This is used in
 166     /// `maybe_iter(true)` to identify the original `LocalCrateContext`.
 167     index: usize,
 168 }
 169
 170 pub struct CrateContextIterator<'a, 'tcx: 'a> {
 171     shared: &'a SharedCrateContext<'a, 'tcx>,
 172     index: usize,
 173 }
 174
 175 impl<'a, 'tcx> Iterator for CrateContextIterator<'a,'tcx> {
 176     type Item = CrateContext<'a, 'tcx>;
 177
 178     fn next(&mut self) -> Option<CrateContext<'a, 'tcx>> {
 179         if self.index >= self.shared.local_ccxs.len() {
 180             return None;
 181         }
 182
 183         let index = self.index;
 184         self.index += 1;
 185
 186         Some(CrateContext {
 187             shared: self.shared,
 188             local: &self.shared.local_ccxs[index],
 189             index: index,
 190         })
 191     }
 192 }
 193
 194 /// The iterator produced by `CrateContext::maybe_iter`.
 195 pub struct CrateContextMaybeIterator<'a, 'tcx: 'a> {
 196     shared: &'a SharedCrateContext<'a, 'tcx>,
 197     index: usize,
 198     single: bool,
 199     origin: usize,
 200 }
 201
 202 impl<'a, 'tcx> Iterator for CrateContextMaybeIterator<'a, 'tcx> {
 203     type Item = (CrateContext<'a, 'tcx>, bool);
 204
 205     fn next(&mut self) -> Option<(CrateContext<'a, 'tcx>, bool)> {
 206         if self.index >= self.shared.local_ccxs.len() {
 207             return None;
 208         }
 209
 210         let index = self.index;
 211         self.index += 1;
 212         if self.single {
 213             self.index = self.shared.local_ccxs.len();
 214         }
 215
 216         let ccx = CrateContext {
 217             shared: self.shared,
 218             local: &self.shared.local_ccxs[index],
 219             index: index,
 220         };
 221         Some((ccx, index == self.origin))
 222     }
 223 }
 224
 225
 226 unsafe fn create_context_and_module(sess: &Session, mod_name: &str) -> (ContextRef, ModuleRef) {
 227     let llcx = llvm::LLVMContextCreate();
 228     let mod_name = CString::new(mod_name).unwrap();
 229     let llmod = llvm::LLVMModuleCreateWithNameInContext(mod_name.as_ptr(), llcx);
 230
 231     let custom_data_layout = &sess.target.target.options.data_layout[..];
 232     if custom_data_layout.len() > 0 {
 233         let data_layout = CString::new(custom_data_layout).unwrap();
 234         llvm::LLVMSetDataLayout(llmod, data_layout.as_ptr());
 235     } else {
 236         let tm = ::back::write::create_target_machine(sess);
 237         llvm::LLVMRustSetDataLayoutFromTargetMachine(llmod, tm);
 238         llvm::LLVMRustDisposeTargetMachine(tm);
 239     }
 240
 241     let llvm_target = sess.target.target.llvm_target.as_bytes();
 242     let llvm_target = CString::new(llvm_target).unwrap();
 243     llvm::LLVMRustSetNormalizedTarget(llmod, llvm_target.as_ptr());
 244     (llcx, llmod)
 245 }
 246
 247 impl<'b, 'tcx> SharedCrateContext<'b, 'tcx> {
 248     pub fn new(crate_name: &str,
 249                local_count: usize,
 250                tcx: &'b ty::ctxt<'tcx>,
 251                export_map: ExportMap,
 252                symbol_hasher: Sha256,
 253                link_meta: LinkMeta,
 254                reachable: NodeSet,
 255                check_overflow: bool,
 256                check_drop_flag_for_sanity: bool)
 257                -> SharedCrateContext<'b, 'tcx> {
 258         let (metadata_llcx, metadata_llmod) = unsafe {
 259             create_context_and_module(&tcx.sess, "metadata")
 260         };
 261
 262         // An interesting part of Windows which MSVC forces our hand on (and
 263         // apparently MinGW didn't) is the usage of `dllimport` and `dllexport`
 264         // attributes in LLVM IR as well as native dependencies (in C these
 265         // correspond to `__declspec(dllimport)`).
 266         //
 267         // Whenever a dynamic library is built by MSVC it must have its public
 268         // interface specified by functions tagged with `dllexport` or otherwise
 269         // they're not available to be linked against. This poses a few problems
 270         // for the compiler, some of which are somewhat fundamental, but we use
 271         // the `use_dll_storage_attrs` variable below to attach the `dllexport`
 272         // attribute to all LLVM functions that are reachable (e.g. they're
 273         // already tagged with external linkage). This is suboptimal for a few
 274         // reasons:
 275         //
 276         // * If an object file will never be included in a dynamic library,
 277         //   there's no need to attach the dllexport attribute. Most object
 278         //   files in Rust are not destined to become part of a dll as binaries
 279         //   are statically linked by default.
 280         // * If the compiler is emitting both an rlib and a dylib, the same
 281         //   source object file is currently used but with MSVC this may be less
 282         //   feasible. The compiler may be able to get around this, but it may
 283         //   involve some invasive changes to deal with this.
 284         //
 285         // The flipside of this situation is that whenever you link to a dll and
 286         // you import a function from it, the import should be tagged with
 287         // `dllimport`. At this time, however, the compiler does not emit
 288         // `dllimport` for any declarations other than constants (where it is
 289         // required), which is again suboptimal for even more reasons!
 290         //
 291         // * Calling a function imported from another dll without using
 292         //   `dllimport` causes the linker/compiler to have extra overhead (one
 293         //   `jmp` instruction on x86) when calling the function.
 294         // * The same object file may be used in different circumstances, so a
 295         //   function may be imported from a dll if the object is linked into a
 296         //   dll, but it may be just linked against if linked into an rlib.
 297         // * The compiler has no knowledge about whether native functions should
 298         //   be tagged dllimport or not.
 299         //
 300         // For now the compiler takes the perf hit (I do not have any numbers to
 301         // this effect) by marking very little as `dllimport` and praying the
 302         // linker will take care of everything. Fixing this problem will likely
 303         // require adding a few attributes to Rust itself (feature gated at the
 304         // start) and then strongly recommending static linkage on MSVC!
 305         let use_dll_storage_attrs = tcx.sess.target.target.options.is_like_msvc;
 306
 307         let mut shared_ccx = SharedCrateContext {
 308             local_ccxs: Vec::with_capacity(local_count),
 309             metadata_llmod: metadata_llmod,
 310             metadata_llcx: metadata_llcx,
 311             export_map: export_map,
 312             reachable: reachable,
 313             item_symbols: RefCell::new(NodeMap()),
 314             link_meta: link_meta,
 315             symbol_hasher: RefCell::new(symbol_hasher),
 316             tcx: tcx,
 317             stats: Stats {
 318                 n_glues_created: Cell::new(0),
 319                 n_null_glues: Cell::new(0),
 320                 n_real_glues: Cell::new(0),
 321                 n_fns: Cell::new(0),
 322                 n_monos: Cell::new(0),
 323                 n_inlines: Cell::new(0),
 324                 n_closures: Cell::new(0),
 325                 n_llvm_insns: Cell::new(0),
 326                 llvm_insns: RefCell::new(FnvHashMap()),
 327                 fn_stats: RefCell::new(Vec::new()),
 328             },
 329             check_overflow: check_overflow,
 330             check_drop_flag_for_sanity: check_drop_flag_for_sanity,
 331             available_drop_glues: RefCell::new(FnvHashMap()),
 332             use_dll_storage_attrs: use_dll_storage_attrs,
 333         };
 334
 335         for i in 0..local_count {
 336             // Append ".rs" to crate name as LLVM module identifier.
 337             //
 338             // LLVM code generator emits a ".file filename" directive
 339             // for ELF backends. Value of the "filename" is set as the
 340             // LLVM module identifier.  Due to a LLVM MC bug[1], LLVM
 341             // crashes if the module identifier is same as other symbols
 342             // such as a function name in the module.
 343             // 1. http://llvm.org/bugs/show_bug.cgi?id=11479
 344             let llmod_id = format!("{}.{}.rs", crate_name, i);
 345             let local_ccx = LocalCrateContext::new(&shared_ccx, &llmod_id[..]);
 346             shared_ccx.local_ccxs.push(local_ccx);
 347         }
 348
 349         shared_ccx
 350     }
 351
 352     pub fn iter<'a>(&'a self) -> CrateContextIterator<'a, 'tcx> {
 353         CrateContextIterator {
 354             shared: self,
 355             index: 0,
 356         }
 357     }
 358
 359     pub fn get_ccx<'a>(&'a self, index: usize) -> CrateContext<'a, 'tcx> {
 360         CrateContext {
 361             shared: self,
 362             local: &self.local_ccxs[index],
 363             index: index,
 364         }
 365     }
 366
 367     fn get_smallest_ccx<'a>(&'a self) -> CrateContext<'a, 'tcx> {
 368         let (local_ccx, index) =
 369             self.local_ccxs
 370                 .iter()
 371                 .zip(0..self.local_ccxs.len())
 372                 .min_by(|&(local_ccx, _idx)| local_ccx.n_llvm_insns.get())
 373                 .unwrap();
 374         CrateContext {
 375             shared: self,
 376             local: local_ccx,
 377             index: index,
 378         }
 379     }
 380
 381
 382     pub fn metadata_llmod(&self) -> ModuleRef {
 383         self.metadata_llmod
 384     }
 385
 386     pub fn metadata_llcx(&self) -> ContextRef {
 387         self.metadata_llcx
 388     }
 389
 390     pub fn export_map<'a>(&'a self) -> &'a ExportMap {
 391         &self.export_map
 392     }
 393
 394     pub fn reachable<'a>(&'a self) -> &'a NodeSet {
 395         &self.reachable
 396     }
 397
 398     pub fn item_symbols<'a>(&'a self) -> &'a RefCell<NodeMap<String>> {
 399         &self.item_symbols
 400     }
 401
 402     pub fn link_meta<'a>(&'a self) -> &'a LinkMeta {
 403         &self.link_meta
 404     }
 405
 406     pub fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx> {
 407         self.tcx
 408     }
 409
 410     pub fn sess<'a>(&'a self) -> &'a Session {
 411         &self.tcx.sess
 412     }
 413
 414     pub fn stats<'a>(&'a self) -> &'a Stats {
 415         &self.stats
 416     }
 417
 418     pub fn use_dll_storage_attrs(&self) -> bool {
 419         self.use_dll_storage_attrs
 420     }
 421 }
 422
 423 impl<'tcx> LocalCrateContext<'tcx> {
 424     fn new<'a>(shared: &SharedCrateContext<'a, 'tcx>,
 425            name: &str)
 426            -> LocalCrateContext<'tcx> {
 427         unsafe {
 428             let (llcx, llmod) = create_context_and_module(&shared.tcx.sess, name);
 429
 430             let dbg_cx = if shared.tcx.sess.opts.debuginfo != NoDebugInfo {
 431                 Some(debuginfo::CrateDebugContext::new(llmod))
 432             } else {
 433                 None
 434             };
 435
 436             let mut local_ccx = LocalCrateContext {
 437                 llmod: llmod,
 438                 llcx: llcx,
 439                 tn: TypeNames::new(),
 440                 externs: RefCell::new(FnvHashMap()),
 441                 item_vals: RefCell::new(NodeMap()),
 442                 needs_unwind_cleanup_cache: RefCell::new(FnvHashMap()),
 443                 fn_pointer_shims: RefCell::new(FnvHashMap()),
 444                 drop_glues: RefCell::new(FnvHashMap()),
 445                 external: RefCell::new(DefIdMap()),
 446                 external_srcs: RefCell::new(NodeMap()),
 447                 monomorphized: RefCell::new(FnvHashMap()),
 448                 monomorphizing: RefCell::new(DefIdMap()),
 449                 available_monomorphizations: RefCell::new(FnvHashSet()),
 450                 vtables: RefCell::new(FnvHashMap()),
 451                 const_cstr_cache: RefCell::new(FnvHashMap()),
 452                 const_unsized: RefCell::new(FnvHashMap()),
 453                 const_globals: RefCell::new(FnvHashMap()),
 454                 const_values: RefCell::new(FnvHashMap()),
 455                 extern_const_values: RefCell::new(DefIdMap()),
 456                 impl_method_cache: RefCell::new(FnvHashMap()),
 457                 closure_bare_wrapper_cache: RefCell::new(FnvHashMap()),
 458                 statics_to_rauw: RefCell::new(Vec::new()),
 459                 lltypes: RefCell::new(FnvHashMap()),
 460                 llsizingtypes: RefCell::new(FnvHashMap()),
 461                 adt_reprs: RefCell::new(FnvHashMap()),
 462                 type_hashcodes: RefCell::new(FnvHashMap()),
 463                 int_type: Type::from_ref(ptr::null_mut()),
 464                 opaque_vec_type: Type::from_ref(ptr::null_mut()),
 465                 builder: BuilderRef_res(llvm::LLVMCreateBuilderInContext(llcx)),
 466                 closure_vals: RefCell::new(FnvHashMap()),
 467                 dbg_cx: dbg_cx,
 468                 eh_personality: RefCell::new(None),
 469                 rust_try_fn: RefCell::new(None),
 470                 unwind_resume_hooked: Cell::new(false),
 471                 intrinsics: RefCell::new(FnvHashMap()),
 472                 n_llvm_insns: Cell::new(0),
 473                 trait_cache: RefCell::new(FnvHashMap()),
 474             };
 475
 476             local_ccx.int_type = Type::int(&local_ccx.dummy_ccx(shared));
 477             local_ccx.opaque_vec_type = Type::opaque_vec(&local_ccx.dummy_ccx(shared));
 478
 479             // Done mutating local_ccx directly.  (The rest of the
 480             // initialization goes through RefCell.)
 481             {
 482                 let ccx = local_ccx.dummy_ccx(shared);
 483
 484                 let mut str_slice_ty = Type::named_struct(&ccx, "str_slice");
 485                 str_slice_ty.set_struct_body(&[Type::i8p(&ccx), ccx.int_type()], false);
 486                 ccx.tn().associate_type("str_slice", &str_slice_ty);
 487
 488                 if ccx.sess().count_llvm_insns() {
 489                     base::init_insn_ctxt()
 490                 }
 491             }
 492
 493             local_ccx
 494         }
 495     }
 496
 497     /// Create a dummy `CrateContext` from `self` and  the provided
 498     /// `SharedCrateContext`.  This is somewhat dangerous because `self` may
 499     /// not actually be an element of `shared.local_ccxs`, which can cause some
 500     /// operations to panic unexpectedly.
 501     ///
 502     /// This is used in the `LocalCrateContext` constructor to allow calling
 503     /// functions that expect a complete `CrateContext`, even before the local
 504     /// portion is fully initialized and attached to the `SharedCrateContext`.
 505     fn dummy_ccx<'a>(&'a self, shared: &'a SharedCrateContext<'a, 'tcx>)
 506                      -> CrateContext<'a, 'tcx> {
 507         CrateContext {
 508             shared: shared,
 509             local: self,
 510             index: !0 as usize,
 511         }
 512     }
 513 }
 514
 515 impl<'b, 'tcx> CrateContext<'b, 'tcx> {
 516     pub fn shared(&self) -> &'b SharedCrateContext<'b, 'tcx> {
 517         self.shared
 518     }
 519
 520     pub fn local(&self) -> &'b LocalCrateContext<'tcx> {
 521         self.local
 522     }
 523
 524
 525     /// Get a (possibly) different `CrateContext` from the same
 526     /// `SharedCrateContext`.
 527     pub fn rotate(&self) -> CrateContext<'b, 'tcx> {
 528         self.shared.get_smallest_ccx()
 529     }
 530
 531     /// Either iterate over only `self`, or iterate over all `CrateContext`s in
 532     /// the `SharedCrateContext`.  The iterator produces `(ccx, is_origin)`
 533     /// pairs, where `is_origin` is `true` if `ccx` is `self` and `false`
 534     /// otherwise.  This method is useful for avoiding code duplication in
 535     /// cases where it may or may not be necessary to translate code into every
 536     /// context.
 537     pub fn maybe_iter(&self, iter_all: bool) -> CrateContextMaybeIterator<'b, 'tcx> {
 538         CrateContextMaybeIterator {
 539             shared: self.shared,
 540             index: if iter_all { 0 } else { self.index },
 541             single: !iter_all,
 542             origin: self.index,
 543         }
 544     }
 545
 546
 547     pub fn tcx<'a>(&'a self) -> &'a ty::ctxt<'tcx> {
 548         self.shared.tcx
 549     }
 550
 551     pub fn sess<'a>(&'a self) -> &'a Session {
 552         &self.shared.tcx.sess
 553     }
 554
 555     pub fn builder<'a>(&'a self) -> Builder<'a, 'tcx> {
 556         Builder::new(self)
 557     }
 558
 559     pub fn raw_builder<'a>(&'a self) -> BuilderRef {
 560         self.local.builder.b
 561     }
 562
 563     pub fn get_intrinsic(&self, key: & &'static str) -> ValueRef {
 564         if let Some(v) = self.intrinsics().borrow().get(key).cloned() {
 565             return v;
 566         }
 567         match declare_intrinsic(self, key) {
 568             Some(v) => return v,
 569             None => panic!()
 570         }
 571     }
 572
 573     pub fn is_split_stack_supported(&self) -> bool {
 574         self.sess().target.target.options.morestack
 575     }
 576
 577
 578     pub fn llmod(&self) -> ModuleRef {
 579         self.local.llmod
 580     }
 581
 582     pub fn llcx(&self) -> ContextRef {
 583         self.local.llcx
 584     }
 585
 586     pub fn td(&self) -> llvm::TargetDataRef {
 587         unsafe { llvm::LLVMRustGetModuleDataLayout(self.llmod()) }
 588     }
 589
 590     pub fn tn<'a>(&'a self) -> &'a TypeNames {
 591         &self.local.tn
 592     }
 593
 594     pub fn externs<'a>(&'a self) -> &'a RefCell<ExternMap> {
 595         &self.local.externs
 596     }
 597
 598     pub fn item_vals<'a>(&'a self) -> &'a RefCell<NodeMap<ValueRef>> {
 599         &self.local.item_vals
 600     }
 601
 602     pub fn export_map<'a>(&'a self) -> &'a ExportMap {
 603         &self.shared.export_map
 604     }
 605
 606     pub fn reachable<'a>(&'a self) -> &'a NodeSet {
 607         &self.shared.reachable
 608     }
 609
 610     pub fn item_symbols<'a>(&'a self) -> &'a RefCell<NodeMap<String>> {
 611         &self.shared.item_symbols
 612     }
 613
 614     pub fn link_meta<'a>(&'a self) -> &'a LinkMeta {
 615         &self.shared.link_meta
 616     }
 617
 618     pub fn needs_unwind_cleanup_cache(&self) -> &RefCell<FnvHashMap<Ty<'tcx>, bool>> {
 619         &self.local.needs_unwind_cleanup_cache
 620     }
 621
 622     pub fn fn_pointer_shims(&self) -> &RefCell<FnvHashMap<Ty<'tcx>, ValueRef>> {
 623         &self.local.fn_pointer_shims
 624     }
 625
 626     pub fn drop_glues<'a>(&'a self) -> &'a RefCell<FnvHashMap<DropGlueKind<'tcx>, ValueRef>> {
 627         &self.local.drop_glues
 628     }
 629
 630     pub fn external<'a>(&'a self) -> &'a RefCell<DefIdMap<Option<ast::NodeId>>> {
 631         &self.local.external
 632     }
 633
 634     pub fn external_srcs<'a>(&'a self) -> &'a RefCell<NodeMap<ast::DefId>> {
 635         &self.local.external_srcs
 636     }
 637
 638     pub fn monomorphized<'a>(&'a self) -> &'a RefCell<FnvHashMap<MonoId<'tcx>, ValueRef>> {
 639         &self.local.monomorphized
 640     }
 641
 642     pub fn monomorphizing<'a>(&'a self) -> &'a RefCell<DefIdMap<usize>> {
 643         &self.local.monomorphizing
 644     }
 645
 646     pub fn vtables<'a>(&'a self) -> &'a RefCell<FnvHashMap<ty::PolyTraitRef<'tcx>, ValueRef>> {
 647         &self.local.vtables
 648     }
 649
 650     pub fn const_cstr_cache<'a>(&'a self) -> &'a RefCell<FnvHashMap<InternedString, ValueRef>> {
 651         &self.local.const_cstr_cache
 652     }
 653
 654     pub fn const_unsized<'a>(&'a self) -> &'a RefCell<FnvHashMap<ValueRef, ValueRef>> {
 655         &self.local.const_unsized
 656     }
 657
 658     pub fn const_globals<'a>(&'a self) -> &'a RefCell<FnvHashMap<ValueRef, ValueRef>> {
 659         &self.local.const_globals
 660     }
 661
 662     pub fn const_values<'a>(&'a self) -> &'a RefCell<FnvHashMap<(ast::NodeId, &'tcx Substs<'tcx>),
 663                                                                 ValueRef>> {
 664         &self.local.const_values
 665     }
 666
 667     pub fn extern_const_values<'a>(&'a self) -> &'a RefCell<DefIdMap<ValueRef>> {
 668         &self.local.extern_const_values
 669     }
 670
 671     pub fn impl_method_cache<'a>(&'a self)
 672             -> &'a RefCell<FnvHashMap<(ast::DefId, ast::Name), ast::DefId>> {
 673         &self.local.impl_method_cache
 674     }
 675
 676     pub fn closure_bare_wrapper_cache<'a>(&'a self) -> &'a RefCell<FnvHashMap<ValueRef, ValueRef>> {
 677         &self.local.closure_bare_wrapper_cache
 678     }
 679
 680     pub fn statics_to_rauw<'a>(&'a self) -> &'a RefCell<Vec<(ValueRef, ValueRef)>> {
 681         &self.local.statics_to_rauw
 682     }
 683
 684     pub fn lltypes<'a>(&'a self) -> &'a RefCell<FnvHashMap<Ty<'tcx>, Type>> {
 685         &self.local.lltypes
 686     }
 687
 688     pub fn llsizingtypes<'a>(&'a self) -> &'a RefCell<FnvHashMap<Ty<'tcx>, Type>> {
 689         &self.local.llsizingtypes
 690     }
 691
 692     pub fn adt_reprs<'a>(&'a self) -> &'a RefCell<FnvHashMap<Ty<'tcx>, Rc<adt::Repr<'tcx>>>> {
 693         &self.local.adt_reprs
 694     }
 695
 696     pub fn symbol_hasher<'a>(&'a self) -> &'a RefCell<Sha256> {
 697         &self.shared.symbol_hasher
 698     }
 699
 700     pub fn type_hashcodes<'a>(&'a self) -> &'a RefCell<FnvHashMap<Ty<'tcx>, String>> {
 701         &self.local.type_hashcodes
 702     }
 703
 704     pub fn stats<'a>(&'a self) -> &'a Stats {
 705         &self.shared.stats
 706     }
 707
 708     pub fn available_monomorphizations<'a>(&'a self) -> &'a RefCell<FnvHashSet<String>> {
 709         &self.local.available_monomorphizations
 710     }
 711
 712     pub fn available_drop_glues(&self) -> &RefCell<FnvHashMap<DropGlueKind<'tcx>, String>> {
 713         &self.shared.available_drop_glues
 714     }
 715
 716     pub fn int_type(&self) -> Type {
 717         self.local.int_type
 718     }
 719
 720     pub fn opaque_vec_type(&self) -> Type {
 721         self.local.opaque_vec_type
 722     }
 723
 724     pub fn closure_vals<'a>(&'a self) -> &'a RefCell<FnvHashMap<MonoId<'tcx>, ValueRef>> {
 725         &self.local.closure_vals
 726     }
 727
 728     pub fn dbg_cx<'a>(&'a self) -> &'a Option<debuginfo::CrateDebugContext<'tcx>> {
 729         &self.local.dbg_cx
 730     }
 731
 732     pub fn eh_personality<'a>(&'a self) -> &'a RefCell<Option<ValueRef>> {
 733         &self.local.eh_personality
 734     }
 735
 736     pub fn rust_try_fn<'a>(&'a self) -> &'a RefCell<Option<ValueRef>> {
 737         &self.local.rust_try_fn
 738     }
 739
 740     pub fn unwind_resume_hooked<'a>(&'a self) -> &'a Cell<bool> {
 741         &self.local.unwind_resume_hooked
 742     }
 743
 744     fn intrinsics<'a>(&'a self) -> &'a RefCell<FnvHashMap<&'static str, ValueRef>> {
 745         &self.local.intrinsics
 746     }
 747
 748     pub fn count_llvm_insn(&self) {
 749         self.local.n_llvm_insns.set(self.local.n_llvm_insns.get() + 1);
 750     }
 751
 752     pub fn trait_cache(&self) -> &RefCell<FnvHashMap<ty::PolyTraitRef<'tcx>,
 753                                                      traits::Vtable<'tcx, ()>>> {
 754         &self.local.trait_cache
 755     }
 756
 757     /// Return exclusive upper bound on object size.
 758     ///
 759     /// The theoretical maximum object size is defined as the maximum positive `int` value. This
 760     /// ensures that the `offset` semantics remain well-defined by allowing it to correctly index
 761     /// every address within an object along with one byte past the end, along with allowing `int`
 762     /// to store the difference between any two pointers into an object.
 763     ///
 764     /// The upper bound on 64-bit currently needs to be lower because LLVM uses a 64-bit integer to
 765     /// represent object size in bits. It would need to be 1 << 61 to account for this, but is
 766     /// currently conservatively bounded to 1 << 47 as that is enough to cover the current usable
 767     /// address space on 64-bit ARMv8 and x86_64.
 768     pub fn obj_size_bound(&self) -> u64 {
 769         match &self.sess().target.target.target_pointer_width[..] {
 770             "32" => 1 << 31,
 771             "64" => 1 << 47,
 772             _ => unreachable!() // error handled by config::build_target_config
 773         }
 774     }
 775
 776     pub fn report_overbig_object(&self, obj: Ty<'tcx>) -> ! {
 777         self.sess().fatal(
 778             &format!("the type `{:?}` is too big for the current architecture",
 779                     obj))
 780     }
 781
 782     pub fn check_overflow(&self) -> bool {
 783         self.shared.check_overflow
 784     }
 785
 786     pub fn check_drop_flag_for_sanity(&self) -> bool {
 787         // This controls whether we emit a conditional llvm.debugtrap
 788         // guarded on whether the dropflag is one of its (two) valid
 789         // values.
 790         self.shared.check_drop_flag_for_sanity
 791     }
 792
 793     pub fn use_dll_storage_attrs(&self) -> bool {
 794         self.shared.use_dll_storage_attrs()
 795     }
 796 }
 797
 798 /// Declare any llvm intrinsics that you might need
 799 fn declare_intrinsic(ccx: &CrateContext, key: & &'static str) -> Option<ValueRef> {
 800     macro_rules! ifn {
 801         ($name:expr, fn() -> $ret:expr) => (
 802             if *key == $name {
 803                 let f = declare::declare_cfn(ccx, $name, Type::func(&[], &$ret),
 804                                              ccx.tcx().mk_nil());
 805                 ccx.intrinsics().borrow_mut().insert($name, f.clone());
 806                 return Some(f);
 807             }
 808         );
 809         ($name:expr, fn($($arg:expr),*) -> $ret:expr) => (
 810             if *key == $name {
 811                 let f = declare::declare_cfn(ccx, $name, Type::func(&[$($arg),*], &$ret),
 812                                              ccx.tcx().mk_nil());
 813                 ccx.intrinsics().borrow_mut().insert($name, f.clone());
 814                 return Some(f);
 815             }
 816         )
 817     }
 818     macro_rules! mk_struct {
 819         ($($field_ty:expr),*) => (Type::struct_(ccx, &[$($field_ty),*], false))
 820     }
 821
 822     let i8p = Type::i8p(ccx);
 823     let void = Type::void(ccx);
 824     let i1 = Type::i1(ccx);
 825     let t_i8 = Type::i8(ccx);
 826     let t_i16 = Type::i16(ccx);
 827     let t_i32 = Type::i32(ccx);
 828     let t_i64 = Type::i64(ccx);
 829     let t_f32 = Type::f32(ccx);
 830     let t_f64 = Type::f64(ccx);
 831
 832     ifn!("llvm.memcpy.p0i8.p0i8.i32", fn(i8p, i8p, t_i32, t_i32, i1) -> void);
 833     ifn!("llvm.memcpy.p0i8.p0i8.i64", fn(i8p, i8p, t_i64, t_i32, i1) -> void);
 834     ifn!("llvm.memmove.p0i8.p0i8.i32", fn(i8p, i8p, t_i32, t_i32, i1) -> void);
 835     ifn!("llvm.memmove.p0i8.p0i8.i64", fn(i8p, i8p, t_i64, t_i32, i1) -> void);
 836     ifn!("llvm.memset.p0i8.i32", fn(i8p, t_i8, t_i32, t_i32, i1) -> void);
 837     ifn!("llvm.memset.p0i8.i64", fn(i8p, t_i8, t_i64, t_i32, i1) -> void);
 838
 839     ifn!("llvm.trap", fn() -> void);
 840     ifn!("llvm.debugtrap", fn() -> void);
 841     ifn!("llvm.frameaddress", fn(t_i32) -> i8p);
 842
 843     ifn!("llvm.powi.f32", fn(t_f32, t_i32) -> t_f32);
 844     ifn!("llvm.powi.f64", fn(t_f64, t_i32) -> t_f64);
 845     ifn!("llvm.pow.f32", fn(t_f32, t_f32) -> t_f32);
 846     ifn!("llvm.pow.f64", fn(t_f64, t_f64) -> t_f64);
 847
 848     ifn!("llvm.sqrt.f32", fn(t_f32) -> t_f32);
 849     ifn!("llvm.sqrt.f64", fn(t_f64) -> t_f64);
 850     ifn!("llvm.sin.f32", fn(t_f32) -> t_f32);
 851     ifn!("llvm.sin.f64", fn(t_f64) -> t_f64);
 852     ifn!("llvm.cos.f32", fn(t_f32) -> t_f32);
 853     ifn!("llvm.cos.f64", fn(t_f64) -> t_f64);
 854     ifn!("llvm.exp.f32", fn(t_f32) -> t_f32);
 855     ifn!("llvm.exp.f64", fn(t_f64) -> t_f64);
 856     ifn!("llvm.exp2.f32", fn(t_f32) -> t_f32);
 857     ifn!("llvm.exp2.f64", fn(t_f64) -> t_f64);
 858     ifn!("llvm.log.f32", fn(t_f32) -> t_f32);
 859     ifn!("llvm.log.f64", fn(t_f64) -> t_f64);
 860     ifn!("llvm.log10.f32", fn(t_f32) -> t_f32);
 861     ifn!("llvm.log10.f64", fn(t_f64) -> t_f64);
 862     ifn!("llvm.log2.f32", fn(t_f32) -> t_f32);
 863     ifn!("llvm.log2.f64", fn(t_f64) -> t_f64);
 864
 865     ifn!("llvm.fma.f32", fn(t_f32, t_f32, t_f32) -> t_f32);
 866     ifn!("llvm.fma.f64", fn(t_f64, t_f64, t_f64) -> t_f64);
 867
 868     ifn!("llvm.fabs.f32", fn(t_f32) -> t_f32);
 869     ifn!("llvm.fabs.f64", fn(t_f64) -> t_f64);
 870
 871     ifn!("llvm.floor.f32", fn(t_f32) -> t_f32);
 872     ifn!("llvm.floor.f64", fn(t_f64) -> t_f64);
 873     ifn!("llvm.ceil.f32", fn(t_f32) -> t_f32);
 874     ifn!("llvm.ceil.f64", fn(t_f64) -> t_f64);
 875     ifn!("llvm.trunc.f32", fn(t_f32) -> t_f32);
 876     ifn!("llvm.trunc.f64", fn(t_f64) -> t_f64);
 877
 878     ifn!("llvm.copysign.f32", fn(t_f32, t_f32) -> t_f32);
 879     ifn!("llvm.copysign.f64", fn(t_f64, t_f64) -> t_f64);
 880     ifn!("llvm.round.f32", fn(t_f32) -> t_f32);
 881     ifn!("llvm.round.f64", fn(t_f64) -> t_f64);
 882
 883     ifn!("llvm.rint.f32", fn(t_f32) -> t_f32);
 884     ifn!("llvm.rint.f64", fn(t_f64) -> t_f64);
 885     ifn!("llvm.nearbyint.f32", fn(t_f32) -> t_f32);
 886     ifn!("llvm.nearbyint.f64", fn(t_f64) -> t_f64);
 887
 888     ifn!("llvm.ctpop.i8", fn(t_i8) -> t_i8);
 889     ifn!("llvm.ctpop.i16", fn(t_i16) -> t_i16);
 890     ifn!("llvm.ctpop.i32", fn(t_i32) -> t_i32);
 891     ifn!("llvm.ctpop.i64", fn(t_i64) -> t_i64);
 892
 893     ifn!("llvm.ctlz.i8", fn(t_i8 , i1) -> t_i8);
 894     ifn!("llvm.ctlz.i16", fn(t_i16, i1) -> t_i16);
 895     ifn!("llvm.ctlz.i32", fn(t_i32, i1) -> t_i32);
 896     ifn!("llvm.ctlz.i64", fn(t_i64, i1) -> t_i64);
 897
 898     ifn!("llvm.cttz.i8", fn(t_i8 , i1) -> t_i8);
 899     ifn!("llvm.cttz.i16", fn(t_i16, i1) -> t_i16);
 900     ifn!("llvm.cttz.i32", fn(t_i32, i1) -> t_i32);
 901     ifn!("llvm.cttz.i64", fn(t_i64, i1) -> t_i64);
 902
 903     ifn!("llvm.bswap.i16", fn(t_i16) -> t_i16);
 904     ifn!("llvm.bswap.i32", fn(t_i32) -> t_i32);
 905     ifn!("llvm.bswap.i64", fn(t_i64) -> t_i64);
 906
 907     ifn!("llvm.sadd.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct!{t_i8, i1});
 908     ifn!("llvm.sadd.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct!{t_i16, i1});
 909     ifn!("llvm.sadd.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct!{t_i32, i1});
 910     ifn!("llvm.sadd.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
 911
 912     ifn!("llvm.uadd.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct!{t_i8, i1});
 913     ifn!("llvm.uadd.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct!{t_i16, i1});
 914     ifn!("llvm.uadd.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct!{t_i32, i1});
 915     ifn!("llvm.uadd.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
 916
 917     ifn!("llvm.ssub.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct!{t_i8, i1});
 918     ifn!("llvm.ssub.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct!{t_i16, i1});
 919     ifn!("llvm.ssub.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct!{t_i32, i1});
 920     ifn!("llvm.ssub.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
 921
 922     ifn!("llvm.usub.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct!{t_i8, i1});
 923     ifn!("llvm.usub.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct!{t_i16, i1});
 924     ifn!("llvm.usub.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct!{t_i32, i1});
 925     ifn!("llvm.usub.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
 926
 927     ifn!("llvm.smul.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct!{t_i8, i1});
 928     ifn!("llvm.smul.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct!{t_i16, i1});
 929     ifn!("llvm.smul.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct!{t_i32, i1});
 930     ifn!("llvm.smul.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
 931
 932     ifn!("llvm.umul.with.overflow.i8", fn(t_i8, t_i8) -> mk_struct!{t_i8, i1});
 933     ifn!("llvm.umul.with.overflow.i16", fn(t_i16, t_i16) -> mk_struct!{t_i16, i1});
 934     ifn!("llvm.umul.with.overflow.i32", fn(t_i32, t_i32) -> mk_struct!{t_i32, i1});
 935     ifn!("llvm.umul.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
 936
 937     ifn!("llvm.lifetime.start", fn(t_i64,i8p) -> void);
 938     ifn!("llvm.lifetime.end", fn(t_i64, i8p) -> void);
 939
 940     ifn!("llvm.expect.i1", fn(i1, i1) -> i1);
 941     ifn!("llvm.eh.typeid.for", fn(i8p) -> t_i32);
 942
 943     // Some intrinsics were introduced in later versions of LLVM, but they have
 944     // fallbacks in libc or libm and such.
 945     macro_rules! compatible_ifn {
 946         ($name:expr, noop($cname:ident ($($arg:expr),*) -> void), $llvm_version:expr) => (
 947             if unsafe { llvm::LLVMVersionMinor() >= $llvm_version } {
 948                 // The `if key == $name` is already in ifn!
 949                 ifn!($name, fn($($arg),*) -> void);
 950             } else if *key == $name {
 951                 let f = declare::declare_cfn(ccx, stringify!($cname),
 952                                              Type::func(&[$($arg),*], &void),
 953                                              ccx.tcx().mk_nil());
 954                 llvm::SetLinkage(f, llvm::InternalLinkage);
 955
 956                 let bld = ccx.builder();
 957                 let llbb = unsafe {
 958                     llvm::LLVMAppendBasicBlockInContext(ccx.llcx(), f,
 959                                                         "entry-block\0".as_ptr() as *const _)
 960                 };
 961
 962                 bld.position_at_end(llbb);
 963                 bld.ret_void();
 964
 965                 ccx.intrinsics().borrow_mut().insert($name, f.clone());
 966                 return Some(f);
 967             }
 968         );
 969         ($name:expr, $cname:ident ($($arg:expr),*) -> $ret:expr, $llvm_version:expr) => (
 970             if unsafe { llvm::LLVMVersionMinor() >= $llvm_version } {
 971                 // The `if key == $name` is already in ifn!
 972                 ifn!($name, fn($($arg),*) -> $ret);
 973             } else if *key == $name {
 974                 let f = declare::declare_cfn(ccx, stringify!($cname),
 975                                              Type::func(&[$($arg),*], &$ret),
 976                                              ccx.tcx().mk_nil());
 977                 ccx.intrinsics().borrow_mut().insert($name, f.clone());
 978                 return Some(f);
 979             }
 980         )
 981     }
 982
 983     compatible_ifn!("llvm.assume", noop(llvmcompat_assume(i1) -> void), 6);
 984
 985     if ccx.sess().opts.debuginfo != NoDebugInfo {
 986         ifn!("llvm.dbg.declare", fn(Type::metadata(ccx), Type::metadata(ccx)) -> void);
 987         ifn!("llvm.dbg.value", fn(Type::metadata(ccx), t_i64, Type::metadata(ccx)) -> void);
 988     }
 989     return None;
 990 }