src/librustc_trans/intrinsic.rs

   1 // Copyright 2012-2014 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 #![allow(non_upper_case_globals)]
  12
  13 use arena::TypedArena;
  14 use intrinsics::{self, Intrinsic};
  15 use libc;
  16 use llvm;
  17 use llvm::{ValueRef, TypeKind};
  18 use rustc::ty::subst;
  19 use rustc::ty::subst::FnSpace;
  20 use abi::{Abi, FnType};
  21 use adt;
  22 use attributes;
  23 use base::*;
  24 use build::*;
  25 use callee::{self, Callee};
  26 use cleanup;
  27 use cleanup::CleanupMethods;
  28 use common::*;
  29 use consts;
  30 use datum::*;
  31 use debuginfo::DebugLoc;
  32 use declare;
  33 use expr;
  34 use glue;
  35 use type_of;
  36 use machine;
  37 use type_::Type;
  38 use rustc::ty::{self, Ty};
  39 use Disr;
  40 use rustc::ty::subst::Substs;
  41 use rustc::hir;
  42 use syntax::ast;
  43 use syntax::ptr::P;
  44 use syntax::parse::token;
  45
  46 use rustc::session::Session;
  47 use syntax_pos::{Span, DUMMY_SP};
  48
  49 use std::cmp::Ordering;
  50
  51 fn get_simple_intrinsic(ccx: &CrateContext, name: &str) -> Option<ValueRef> {
  52     let llvm_name = match name {
  53         "sqrtf32" => "llvm.sqrt.f32",
  54         "sqrtf64" => "llvm.sqrt.f64",
  55         "powif32" => "llvm.powi.f32",
  56         "powif64" => "llvm.powi.f64",
  57         "sinf32" => "llvm.sin.f32",
  58         "sinf64" => "llvm.sin.f64",
  59         "cosf32" => "llvm.cos.f32",
  60         "cosf64" => "llvm.cos.f64",
  61         "powf32" => "llvm.pow.f32",
  62         "powf64" => "llvm.pow.f64",
  63         "expf32" => "llvm.exp.f32",
  64         "expf64" => "llvm.exp.f64",
  65         "exp2f32" => "llvm.exp2.f32",
  66         "exp2f64" => "llvm.exp2.f64",
  67         "logf32" => "llvm.log.f32",
  68         "logf64" => "llvm.log.f64",
  69         "log10f32" => "llvm.log10.f32",
  70         "log10f64" => "llvm.log10.f64",
  71         "log2f32" => "llvm.log2.f32",
  72         "log2f64" => "llvm.log2.f64",
  73         "fmaf32" => "llvm.fma.f32",
  74         "fmaf64" => "llvm.fma.f64",
  75         "fabsf32" => "llvm.fabs.f32",
  76         "fabsf64" => "llvm.fabs.f64",
  77         "copysignf32" => "llvm.copysign.f32",
  78         "copysignf64" => "llvm.copysign.f64",
  79         "floorf32" => "llvm.floor.f32",
  80         "floorf64" => "llvm.floor.f64",
  81         "ceilf32" => "llvm.ceil.f32",
  82         "ceilf64" => "llvm.ceil.f64",
  83         "truncf32" => "llvm.trunc.f32",
  84         "truncf64" => "llvm.trunc.f64",
  85         "rintf32" => "llvm.rint.f32",
  86         "rintf64" => "llvm.rint.f64",
  87         "nearbyintf32" => "llvm.nearbyint.f32",
  88         "nearbyintf64" => "llvm.nearbyint.f64",
  89         "roundf32" => "llvm.round.f32",
  90         "roundf64" => "llvm.round.f64",
  91         "assume" => "llvm.assume",
  92         _ => return None
  93     };
  94     Some(ccx.get_intrinsic(&llvm_name))
  95 }
  96
  97 /// Remember to add all intrinsics here, in librustc_typeck/check/mod.rs,
  98 /// and in libcore/intrinsics.rs; if you need access to any llvm intrinsics,
  99 /// add them to librustc_trans/trans/context.rs
 100 pub fn trans_intrinsic_call<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
 101                                             callee_ty: Ty<'tcx>,
 102                                             fn_ty: &FnType,
 103                                             args: callee::CallArgs<'a, 'tcx>,
 104                                             dest: expr::Dest,
 105                                             call_debug_location: DebugLoc)
 106                                             -> Result<'blk, 'tcx> {
 107     let fcx = bcx.fcx;
 108     let ccx = fcx.ccx;
 109     let tcx = bcx.tcx();
 110
 111     let _icx = push_ctxt("trans_intrinsic_call");
 112
 113     let (def_id, substs, sig) = match callee_ty.sty {
 114         ty::TyFnDef(def_id, substs, fty) => {
 115             let sig = tcx.erase_late_bound_regions(&fty.sig);
 116             (def_id, substs, tcx.normalize_associated_type(&sig))
 117         }
 118         _ => bug!("expected fn item type, found {}", callee_ty)
 119     };
 120     let arg_tys = sig.inputs;
 121     let ret_ty = sig.output;
 122     let name = tcx.item_name(def_id).as_str();
 123
 124     let span = match call_debug_location {
 125         DebugLoc::At(_, span) | DebugLoc::ScopeAt(_, span) => span,
 126         DebugLoc::None => {
 127             span_bug!(fcx.span.unwrap_or(DUMMY_SP),
 128                       "intrinsic `{}` called with missing span", name);
 129         }
 130     };
 131
 132     let cleanup_scope = fcx.push_custom_cleanup_scope();
 133
 134     // For `transmute` we can just trans the input expr directly into dest
 135     if name == "transmute" {
 136         let llret_ty = type_of::type_of(ccx, ret_ty.unwrap());
 137         match args {
 138             callee::ArgExprs(arg_exprs) => {
 139                 assert_eq!(arg_exprs.len(), 1);
 140
 141                 let (in_type, out_type) = (*substs.types.get(FnSpace, 0),
 142                                            *substs.types.get(FnSpace, 1));
 143                 let llintype = type_of::type_of(ccx, in_type);
 144                 let llouttype = type_of::type_of(ccx, out_type);
 145
 146                 let in_type_size = machine::llbitsize_of_real(ccx, llintype);
 147                 let out_type_size = machine::llbitsize_of_real(ccx, llouttype);
 148
 149                 if let ty::TyFnDef(def_id, substs, _) = in_type.sty {
 150                     if out_type_size != 0 {
 151                         // FIXME #19925 Remove this hack after a release cycle.
 152                         let _ = unpack_datum!(bcx, expr::trans(bcx, &arg_exprs[0]));
 153                         let llfn = Callee::def(ccx, def_id, substs).reify(ccx).val;
 154                         let llfnty = val_ty(llfn);
 155                         let llresult = match dest {
 156                             expr::SaveIn(d) => d,
 157                             expr::Ignore => alloc_ty(bcx, out_type, "ret")
 158                         };
 159                         Store(bcx, llfn, PointerCast(bcx, llresult, llfnty.ptr_to()));
 160                         if dest == expr::Ignore {
 161                             bcx = glue::drop_ty(bcx, llresult, out_type,
 162                                                 call_debug_location);
 163                         }
 164                         fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
 165                         fcx.pop_and_trans_custom_cleanup_scope(bcx, cleanup_scope);
 166                         return Result::new(bcx, llresult);
 167                     }
 168                 }
 169
 170                 // This should be caught by the intrinsicck pass
 171                 assert_eq!(in_type_size, out_type_size);
 172
 173                 let nonpointer_nonaggregate = |llkind: TypeKind| -> bool {
 174                     use llvm::TypeKind::*;
 175                     match llkind {
 176                         Half | Float | Double | X86_FP80 | FP128 |
 177                             PPC_FP128 | Integer | Vector | X86_MMX => true,
 178                         _ => false
 179                     }
 180                 };
 181
 182                 // An approximation to which types can be directly cast via
 183                 // LLVM's bitcast.  This doesn't cover pointer -> pointer casts,
 184                 // but does, importantly, cover SIMD types.
 185                 let in_kind = llintype.kind();
 186                 let ret_kind = llret_ty.kind();
 187                 let bitcast_compatible =
 188                     (nonpointer_nonaggregate(in_kind) && nonpointer_nonaggregate(ret_kind)) || {
 189                         in_kind == TypeKind::Pointer && ret_kind == TypeKind::Pointer
 190                     };
 191
 192                 let dest = if bitcast_compatible {
 193                     // if we're here, the type is scalar-like (a primitive, a
 194                     // SIMD type or a pointer), and so can be handled as a
 195                     // by-value ValueRef and can also be directly bitcast to the
 196                     // target type.  Doing this special case makes conversions
 197                     // like `u32x4` -> `u64x2` much nicer for LLVM and so more
 198                     // efficient (these are done efficiently implicitly in C
 199                     // with the `__m128i` type and so this means Rust doesn't
 200                     // lose out there).
 201                     let expr = &arg_exprs[0];
 202                     let datum = unpack_datum!(bcx, expr::trans(bcx, expr));
 203                     let datum = unpack_datum!(bcx, datum.to_rvalue_datum(bcx, "transmute_temp"));
 204                     let val = if datum.kind.is_by_ref() {
 205                         load_ty(bcx, datum.val, datum.ty)
 206                     } else {
 207                         from_immediate(bcx, datum.val)
 208                     };
 209
 210                     let cast_val = BitCast(bcx, val, llret_ty);
 211
 212                     match dest {
 213                         expr::SaveIn(d) => {
 214                             // this often occurs in a sequence like `Store(val,
 215                             // d); val2 = Load(d)`, so disappears easily.
 216                             Store(bcx, cast_val, d);
 217                         }
 218                         expr::Ignore => {}
 219                     }
 220                     dest
 221                 } else {
 222                     // The types are too complicated to do with a by-value
 223                     // bitcast, so pointer cast instead. We need to cast the
 224                     // dest so the types work out.
 225                     let dest = match dest {
 226                         expr::SaveIn(d) => expr::SaveIn(PointerCast(bcx, d, llintype.ptr_to())),
 227                         expr::Ignore => expr::Ignore
 228                     };
 229                     bcx = expr::trans_into(bcx, &arg_exprs[0], dest);
 230                     dest
 231                 };
 232
 233                 fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
 234                 fcx.pop_and_trans_custom_cleanup_scope(bcx, cleanup_scope);
 235
 236                 return match dest {
 237                     expr::SaveIn(d) => Result::new(bcx, d),
 238                     expr::Ignore => Result::new(bcx, C_undef(llret_ty.ptr_to()))
 239                 };
 240
 241             }
 242
 243             _ => {
 244                 bug!("expected expr as argument for transmute");
 245             }
 246         }
 247     }
 248
 249     // For `move_val_init` we can evaluate the destination address
 250     // (the first argument) and then trans the source value (the
 251     // second argument) directly into the resulting destination
 252     // address.
 253     if name == "move_val_init" {
 254         if let callee::ArgExprs(ref exprs) = args {
 255             let (dest_expr, source_expr) = if exprs.len() != 2 {
 256                 bug!("expected two exprs as arguments for `move_val_init` intrinsic");
 257             } else {
 258                 (&exprs[0], &exprs[1])
 259             };
 260
 261             // evaluate destination address
 262             let dest_datum = unpack_datum!(bcx, expr::trans(bcx, dest_expr));
 263             let dest_datum = unpack_datum!(
 264                 bcx, dest_datum.to_rvalue_datum(bcx, "arg"));
 265             let dest_datum = unpack_datum!(
 266                 bcx, dest_datum.to_appropriate_datum(bcx));
 267
 268             // `expr::trans_into(bcx, expr, dest)` is equiv to
 269             //
 270             //    `trans(bcx, expr).store_to_dest(dest)`,
 271             //
 272             // which for `dest == expr::SaveIn(addr)`, is equivalent to:
 273             //
 274             //    `trans(bcx, expr).store_to(bcx, addr)`.
 275             let lldest = expr::Dest::SaveIn(dest_datum.val);
 276             bcx = expr::trans_into(bcx, source_expr, lldest);
 277
 278             let llresult = C_nil(ccx);
 279             fcx.pop_and_trans_custom_cleanup_scope(bcx, cleanup_scope);
 280
 281             return Result::new(bcx, llresult);
 282         } else {
 283             bug!("expected two exprs as arguments for `move_val_init` intrinsic");
 284         }
 285     }
 286
 287     // save the actual AST arguments for later (some places need to do
 288     // const-evaluation on them)
 289     let expr_arguments = match args {
 290         callee::ArgExprs(args) => Some(args),
 291         _ => None,
 292     };
 293
 294     // Push the arguments.
 295     let mut llargs = Vec::new();
 296     bcx = callee::trans_args(bcx,
 297                              Abi::RustIntrinsic,
 298                              fn_ty,
 299                              &mut callee::Intrinsic,
 300                              args,
 301                              &mut llargs,
 302                              cleanup::CustomScope(cleanup_scope));
 303
 304     fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
 305
 306     // These are the only intrinsic functions that diverge.
 307     if name == "abort" {
 308         let llfn = ccx.get_intrinsic(&("llvm.trap"));
 309         Call(bcx, llfn, &[], call_debug_location);
 310         fcx.pop_and_trans_custom_cleanup_scope(bcx, cleanup_scope);
 311         Unreachable(bcx);
 312         return Result::new(bcx, C_undef(Type::nil(ccx).ptr_to()));
 313     } else if &name[..] == "unreachable" {
 314         fcx.pop_and_trans_custom_cleanup_scope(bcx, cleanup_scope);
 315         Unreachable(bcx);
 316         return Result::new(bcx, C_nil(ccx));
 317     }
 318
 319     let ret_ty = match ret_ty {
 320         ty::FnConverging(ret_ty) => ret_ty,
 321         ty::FnDiverging => bug!()
 322     };
 323
 324     let llret_ty = type_of::type_of(ccx, ret_ty);
 325
 326     // Get location to store the result. If the user does
 327     // not care about the result, just make a stack slot
 328     let llresult = match dest {
 329         expr::SaveIn(d) => d,
 330         expr::Ignore => {
 331             if !type_is_zero_size(ccx, ret_ty) {
 332                 let llresult = alloc_ty(bcx, ret_ty, "intrinsic_result");
 333                 call_lifetime_start(bcx, llresult);
 334                 llresult
 335             } else {
 336                 C_undef(llret_ty.ptr_to())
 337             }
 338         }
 339     };
 340
 341     let simple = get_simple_intrinsic(ccx, &name);
 342     let llval = match (simple, &name[..]) {
 343         (Some(llfn), _) => {
 344             Call(bcx, llfn, &llargs, call_debug_location)
 345         }
 346         (_, "try") => {
 347             bcx = try_intrinsic(bcx, llargs[0], llargs[1], llargs[2], llresult,
 348                                 call_debug_location);
 349             C_nil(ccx)
 350         }
 351         (_, "breakpoint") => {
 352             let llfn = ccx.get_intrinsic(&("llvm.debugtrap"));
 353             Call(bcx, llfn, &[], call_debug_location)
 354         }
 355         (_, "size_of") => {
 356             let tp_ty = *substs.types.get(FnSpace, 0);
 357             let lltp_ty = type_of::type_of(ccx, tp_ty);
 358             C_uint(ccx, machine::llsize_of_alloc(ccx, lltp_ty))
 359         }
 360         (_, "size_of_val") => {
 361             let tp_ty = *substs.types.get(FnSpace, 0);
 362             if !type_is_sized(tcx, tp_ty) {
 363                 let (llsize, _) =
 364                     glue::size_and_align_of_dst(&bcx.build(), tp_ty, llargs[1]);
 365                 llsize
 366             } else {
 367                 let lltp_ty = type_of::type_of(ccx, tp_ty);
 368                 C_uint(ccx, machine::llsize_of_alloc(ccx, lltp_ty))
 369             }
 370         }
 371         (_, "min_align_of") => {
 372             let tp_ty = *substs.types.get(FnSpace, 0);
 373             C_uint(ccx, type_of::align_of(ccx, tp_ty))
 374         }
 375         (_, "min_align_of_val") => {
 376             let tp_ty = *substs.types.get(FnSpace, 0);
 377             if !type_is_sized(tcx, tp_ty) {
 378                 let (_, llalign) =
 379                     glue::size_and_align_of_dst(&bcx.build(), tp_ty, llargs[1]);
 380                 llalign
 381             } else {
 382                 C_uint(ccx, type_of::align_of(ccx, tp_ty))
 383             }
 384         }
 385         (_, "pref_align_of") => {
 386             let tp_ty = *substs.types.get(FnSpace, 0);
 387             let lltp_ty = type_of::type_of(ccx, tp_ty);
 388             C_uint(ccx, machine::llalign_of_pref(ccx, lltp_ty))
 389         }
 390         (_, "drop_in_place") => {
 391             let tp_ty = *substs.types.get(FnSpace, 0);
 392             let ptr = if type_is_sized(tcx, tp_ty) {
 393                 llargs[0]
 394             } else {
 395                 let scratch = rvalue_scratch_datum(bcx, tp_ty, "tmp");
 396                 Store(bcx, llargs[0], expr::get_dataptr(bcx, scratch.val));
 397                 Store(bcx, llargs[1], expr::get_meta(bcx, scratch.val));
 398                 fcx.schedule_lifetime_end(cleanup::CustomScope(cleanup_scope), scratch.val);
 399                 scratch.val
 400             };
 401             glue::drop_ty(bcx, ptr, tp_ty, call_debug_location);
 402             C_nil(ccx)
 403         }
 404         (_, "type_name") => {
 405             let tp_ty = *substs.types.get(FnSpace, 0);
 406             let ty_name = token::intern_and_get_ident(&tp_ty.to_string());
 407             C_str_slice(ccx, ty_name)
 408         }
 409         (_, "type_id") => {
 410             let hash = ccx.tcx().hash_crate_independent(*substs.types.get(FnSpace, 0),
 411                                                         &ccx.link_meta().crate_hash);
 412             C_u64(ccx, hash)
 413         }
 414         (_, "init_dropped") => {
 415             let tp_ty = *substs.types.get(FnSpace, 0);
 416             if !type_is_zero_size(ccx, tp_ty) {
 417                 drop_done_fill_mem(bcx, llresult, tp_ty);
 418             }
 419             C_nil(ccx)
 420         }
 421         (_, "init") => {
 422             let tp_ty = *substs.types.get(FnSpace, 0);
 423             if !type_is_zero_size(ccx, tp_ty) {
 424                 // Just zero out the stack slot. (See comment on base::memzero for explanation)
 425                 init_zero_mem(bcx, llresult, tp_ty);
 426             }
 427             C_nil(ccx)
 428         }
 429         // Effectively no-ops
 430         (_, "uninit") | (_, "forget") => {
 431             C_nil(ccx)
 432         }
 433         (_, "needs_drop") => {
 434             let tp_ty = *substs.types.get(FnSpace, 0);
 435
 436             C_bool(ccx, bcx.fcx.type_needs_drop(tp_ty))
 437         }
 438         (_, "offset") => {
 439             let ptr = llargs[0];
 440             let offset = llargs[1];
 441             InBoundsGEP(bcx, ptr, &[offset])
 442         }
 443         (_, "arith_offset") => {
 444             let ptr = llargs[0];
 445             let offset = llargs[1];
 446             GEP(bcx, ptr, &[offset])
 447         }
 448
 449         (_, "copy_nonoverlapping") => {
 450             copy_intrinsic(bcx,
 451                            false,
 452                            false,
 453                            *substs.types.get(FnSpace, 0),
 454                            llargs[1],
 455                            llargs[0],
 456                            llargs[2],
 457                            call_debug_location)
 458         }
 459         (_, "copy") => {
 460             copy_intrinsic(bcx,
 461                            true,
 462                            false,
 463                            *substs.types.get(FnSpace, 0),
 464                            llargs[1],
 465                            llargs[0],
 466                            llargs[2],
 467                            call_debug_location)
 468         }
 469         (_, "write_bytes") => {
 470             memset_intrinsic(bcx,
 471                              false,
 472                              *substs.types.get(FnSpace, 0),
 473                              llargs[0],
 474                              llargs[1],
 475                              llargs[2],
 476                              call_debug_location)
 477         }
 478
 479         (_, "volatile_copy_nonoverlapping_memory") => {
 480             copy_intrinsic(bcx,
 481                            false,
 482                            true,
 483                            *substs.types.get(FnSpace, 0),
 484                            llargs[0],
 485                            llargs[1],
 486                            llargs[2],
 487                            call_debug_location)
 488         }
 489         (_, "volatile_copy_memory") => {
 490             copy_intrinsic(bcx,
 491                            true,
 492                            true,
 493                            *substs.types.get(FnSpace, 0),
 494                            llargs[0],
 495                            llargs[1],
 496                            llargs[2],
 497                            call_debug_location)
 498         }
 499         (_, "volatile_set_memory") => {
 500             memset_intrinsic(bcx,
 501                              true,
 502                              *substs.types.get(FnSpace, 0),
 503                              llargs[0],
 504                              llargs[1],
 505                              llargs[2],
 506                              call_debug_location)
 507         }
 508         (_, "volatile_load") => {
 509             let tp_ty = *substs.types.get(FnSpace, 0);
 510             let mut ptr = llargs[0];
 511             if let Some(ty) = fn_ty.ret.cast {
 512                 ptr = PointerCast(bcx, ptr, ty.ptr_to());
 513             }
 514             let load = VolatileLoad(bcx, ptr);
 515             unsafe {
 516                 llvm::LLVMSetAlignment(load, type_of::align_of(ccx, tp_ty));
 517             }
 518             to_immediate(bcx, load, tp_ty)
 519         },
 520         (_, "volatile_store") => {
 521             let tp_ty = *substs.types.get(FnSpace, 0);
 522             if type_is_fat_ptr(bcx.tcx(), tp_ty) {
 523                 VolatileStore(bcx, llargs[1], expr::get_dataptr(bcx, llargs[0]));
 524                 VolatileStore(bcx, llargs[2], expr::get_meta(bcx, llargs[0]));
 525             } else {
 526                 let val = if fn_ty.args[1].is_indirect() {
 527                     Load(bcx, llargs[1])
 528                 } else {
 529                     from_immediate(bcx, llargs[1])
 530                 };
 531                 let ptr = PointerCast(bcx, llargs[0], val_ty(val).ptr_to());
 532                 let store = VolatileStore(bcx, val, ptr);
 533                 unsafe {
 534                     llvm::LLVMSetAlignment(store, type_of::align_of(ccx, tp_ty));
 535                 }
 536             }
 537             C_nil(ccx)
 538         },
 539
 540         (_, "ctlz") | (_, "cttz") | (_, "ctpop") | (_, "bswap") |
 541         (_, "add_with_overflow") | (_, "sub_with_overflow") | (_, "mul_with_overflow") |
 542         (_, "overflowing_add") | (_, "overflowing_sub") | (_, "overflowing_mul") |
 543         (_, "unchecked_div") | (_, "unchecked_rem") => {
 544             let sty = &arg_tys[0].sty;
 545             match int_type_width_signed(sty, ccx) {
 546                 Some((width, signed)) =>
 547                     match &*name {
 548                         "ctlz" => count_zeros_intrinsic(bcx, &format!("llvm.ctlz.i{}", width),
 549                                                         llargs[0], call_debug_location),
 550                         "cttz" => count_zeros_intrinsic(bcx, &format!("llvm.cttz.i{}", width),
 551                                                         llargs[0], call_debug_location),
 552                         "ctpop" => Call(bcx, ccx.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 553                                         &llargs, call_debug_location),
 554                         "bswap" => {
 555                             if width == 8 {
 556                                 llargs[0] // byte swap a u8/i8 is just a no-op
 557                             } else {
 558                                 Call(bcx, ccx.get_intrinsic(&format!("llvm.bswap.i{}", width)),
 559                                         &llargs, call_debug_location)
 560                             }
 561                         }
 562                         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" => {
 563                             let intrinsic = format!("llvm.{}{}.with.overflow.i{}",
 564                                                     if signed { 's' } else { 'u' },
 565                                                     &name[..3], width);
 566                             with_overflow_intrinsic(bcx, &intrinsic, llargs[0], llargs[1], llresult,
 567                                                     call_debug_location)
 568                         },
 569                         "overflowing_add" => Add(bcx, llargs[0], llargs[1], call_debug_location),
 570                         "overflowing_sub" => Sub(bcx, llargs[0], llargs[1], call_debug_location),
 571                         "overflowing_mul" => Mul(bcx, llargs[0], llargs[1], call_debug_location),
 572                         "unchecked_div" =>
 573                             if signed {
 574                                 SDiv(bcx, llargs[0], llargs[1], call_debug_location)
 575                             } else {
 576                                 UDiv(bcx, llargs[0], llargs[1], call_debug_location)
 577                             },
 578                         "unchecked_rem" =>
 579                             if signed {
 580                                 SRem(bcx, llargs[0], llargs[1], call_debug_location)
 581                             } else {
 582                                 URem(bcx, llargs[0], llargs[1], call_debug_location)
 583                             },
 584                         _ => bug!(),
 585                     },
 586                 None => {
 587                     span_invalid_monomorphization_error(
 588                         tcx.sess, span,
 589                         &format!("invalid monomorphization of `{}` intrinsic: \
 590                                   expected basic integer type, found `{}`", name, sty));
 591                         C_nil(ccx)
 592                 }
 593             }
 594
 595         },
 596         (_, "fadd_fast") | (_, "fsub_fast") | (_, "fmul_fast") | (_, "fdiv_fast") |
 597         (_, "frem_fast") => {
 598             let sty = &arg_tys[0].sty;
 599             match float_type_width(sty) {
 600                 Some(_width) =>
 601                     match &*name {
 602                         "fadd_fast" => FAddFast(bcx, llargs[0], llargs[1], call_debug_location),
 603                         "fsub_fast" => FSubFast(bcx, llargs[0], llargs[1], call_debug_location),
 604                         "fmul_fast" => FMulFast(bcx, llargs[0], llargs[1], call_debug_location),
 605                         "fdiv_fast" => FDivFast(bcx, llargs[0], llargs[1], call_debug_location),
 606                         "frem_fast" => FRemFast(bcx, llargs[0], llargs[1], call_debug_location),
 607                         _ => bug!(),
 608                     },
 609                 None => {
 610                     span_invalid_monomorphization_error(
 611                         tcx.sess, span,
 612                         &format!("invalid monomorphization of `{}` intrinsic: \
 613                                   expected basic float type, found `{}`", name, sty));
 614                         C_nil(ccx)
 615                 }
 616             }
 617
 618         },
 619
 620         (_, "discriminant_value") => {
 621             let val_ty = substs.types.get(FnSpace, 0);
 622             match val_ty.sty {
 623                 ty::TyEnum(..) => {
 624                     let repr = adt::represent_type(ccx, *val_ty);
 625                     adt::trans_get_discr(bcx, &repr, llargs[0],
 626                                          Some(llret_ty), true)
 627                 }
 628                 _ => C_null(llret_ty)
 629             }
 630         }
 631         (_, name) if name.starts_with("simd_") => {
 632             generic_simd_intrinsic(bcx, name,
 633                                    substs,
 634                                    callee_ty,
 635                                    expr_arguments,
 636                                    &llargs,
 637                                    ret_ty, llret_ty,
 638                                    call_debug_location,
 639                                    span)
 640         }
 641         // This requires that atomic intrinsics follow a specific naming pattern:
 642         // "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
 643         (_, name) if name.starts_with("atomic_") => {
 644             let split: Vec<&str> = name.split('_').collect();
 645
 646             let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
 647             let (order, failorder) = match split.len() {
 648                 2 => (llvm::SequentiallyConsistent, llvm::SequentiallyConsistent),
 649                 3 => match split[2] {
 650                     "unordered" => (llvm::Unordered, llvm::Unordered),
 651                     "relaxed" => (llvm::Monotonic, llvm::Monotonic),
 652                     "acq"     => (llvm::Acquire, llvm::Acquire),
 653                     "rel"     => (llvm::Release, llvm::Monotonic),
 654                     "acqrel"  => (llvm::AcquireRelease, llvm::Acquire),
 655                     "failrelaxed" if is_cxchg =>
 656                         (llvm::SequentiallyConsistent, llvm::Monotonic),
 657                     "failacq" if is_cxchg =>
 658                         (llvm::SequentiallyConsistent, llvm::Acquire),
 659                     _ => ccx.sess().fatal("unknown ordering in atomic intrinsic")
 660                 },
 661                 4 => match (split[2], split[3]) {
 662                     ("acq", "failrelaxed") if is_cxchg =>
 663                         (llvm::Acquire, llvm::Monotonic),
 664                     ("acqrel", "failrelaxed") if is_cxchg =>
 665                         (llvm::AcquireRelease, llvm::Monotonic),
 666                     _ => ccx.sess().fatal("unknown ordering in atomic intrinsic")
 667                 },
 668                 _ => ccx.sess().fatal("Atomic intrinsic not in correct format"),
 669             };
 670
 671             match split[1] {
 672                 "cxchg" | "cxchgweak" => {
 673                     let sty = &substs.types.get(FnSpace, 0).sty;
 674                     if int_type_width_signed(sty, ccx).is_some() {
 675                         let weak = if split[1] == "cxchgweak" { llvm::True } else { llvm::False };
 676                         let val = AtomicCmpXchg(bcx, llargs[0], llargs[1], llargs[2],
 677                                                 order, failorder, weak);
 678                         let result = ExtractValue(bcx, val, 0);
 679                         let success = ZExt(bcx, ExtractValue(bcx, val, 1), Type::bool(bcx.ccx()));
 680                         Store(bcx, result, StructGEP(bcx, llresult, 0));
 681                         Store(bcx, success, StructGEP(bcx, llresult, 1));
 682                     } else {
 683                         span_invalid_monomorphization_error(
 684                             tcx.sess, span,
 685                             &format!("invalid monomorphization of `{}` intrinsic: \
 686                                       expected basic integer type, found `{}`", name, sty));
 687                     }
 688                     C_nil(ccx)
 689                 }
 690
 691                 "load" => {
 692                     let sty = &substs.types.get(FnSpace, 0).sty;
 693                     if int_type_width_signed(sty, ccx).is_some() {
 694                         AtomicLoad(bcx, llargs[0], order)
 695                     } else {
 696                         span_invalid_monomorphization_error(
 697                             tcx.sess, span,
 698                             &format!("invalid monomorphization of `{}` intrinsic: \
 699                                       expected basic integer type, found `{}`", name, sty));
 700                         C_nil(ccx)
 701                     }
 702                 }
 703
 704                 "store" => {
 705                     let sty = &substs.types.get(FnSpace, 0).sty;
 706                     if int_type_width_signed(sty, ccx).is_some() {
 707                         AtomicStore(bcx, llargs[1], llargs[0], order);
 708                     } else {
 709                         span_invalid_monomorphization_error(
 710                             tcx.sess, span,
 711                             &format!("invalid monomorphization of `{}` intrinsic: \
 712                                       expected basic integer type, found `{}`", name, sty));
 713                     }
 714                     C_nil(ccx)
 715                 }
 716
 717                 "fence" => {
 718                     AtomicFence(bcx, order, llvm::CrossThread);
 719                     C_nil(ccx)
 720                 }
 721
 722                 "singlethreadfence" => {
 723                     AtomicFence(bcx, order, llvm::SingleThread);
 724                     C_nil(ccx)
 725                 }
 726
 727                 // These are all AtomicRMW ops
 728                 op => {
 729                     let atom_op = match op {
 730                         "xchg"  => llvm::AtomicXchg,
 731                         "xadd"  => llvm::AtomicAdd,
 732                         "xsub"  => llvm::AtomicSub,
 733                         "and"   => llvm::AtomicAnd,
 734                         "nand"  => llvm::AtomicNand,
 735                         "or"    => llvm::AtomicOr,
 736                         "xor"   => llvm::AtomicXor,
 737                         "max"   => llvm::AtomicMax,
 738                         "min"   => llvm::AtomicMin,
 739                         "umax"  => llvm::AtomicUMax,
 740                         "umin"  => llvm::AtomicUMin,
 741                         _ => ccx.sess().fatal("unknown atomic operation")
 742                     };
 743
 744                     let sty = &substs.types.get(FnSpace, 0).sty;
 745                     if int_type_width_signed(sty, ccx).is_some() {
 746                         AtomicRMW(bcx, atom_op, llargs[0], llargs[1], order)
 747                     } else {
 748                         span_invalid_monomorphization_error(
 749                             tcx.sess, span,
 750                             &format!("invalid monomorphization of `{}` intrinsic: \
 751                                       expected basic integer type, found `{}`", name, sty));
 752                         C_nil(ccx)
 753                     }
 754                 }
 755             }
 756
 757         }
 758
 759         (_, _) => {
 760             let intr = match Intrinsic::find(&name) {
 761                 Some(intr) => intr,
 762                 None => bug!("unknown intrinsic '{}'", name),
 763             };
 764             fn one<T>(x: Vec<T>) -> T {
 765                 assert_eq!(x.len(), 1);
 766                 x.into_iter().next().unwrap()
 767             }
 768             fn ty_to_type(ccx: &CrateContext, t: &intrinsics::Type,
 769                           any_changes_needed: &mut bool) -> Vec<Type> {
 770                 use intrinsics::Type::*;
 771                 match *t {
 772                     Void => vec![Type::void(ccx)],
 773                     Integer(_signed, width, llvm_width) => {
 774                         *any_changes_needed |= width != llvm_width;
 775                         vec![Type::ix(ccx, llvm_width as u64)]
 776                     }
 777                     Float(x) => {
 778                         match x {
 779                             32 => vec![Type::f32(ccx)],
 780                             64 => vec![Type::f64(ccx)],
 781                             _ => bug!()
 782                         }
 783                     }
 784                     Pointer(ref t, ref llvm_elem, _const) => {
 785                         *any_changes_needed |= llvm_elem.is_some();
 786
 787                         let t = llvm_elem.as_ref().unwrap_or(t);
 788                         let elem = one(ty_to_type(ccx, t,
 789                                                   any_changes_needed));
 790                         vec![elem.ptr_to()]
 791                     }
 792                     Vector(ref t, ref llvm_elem, length) => {
 793                         *any_changes_needed |= llvm_elem.is_some();
 794
 795                         let t = llvm_elem.as_ref().unwrap_or(t);
 796                         let elem = one(ty_to_type(ccx, t,
 797                                                   any_changes_needed));
 798                         vec![Type::vector(&elem,
 799                                           length as u64)]
 800                     }
 801                     Aggregate(false, ref contents) => {
 802                         let elems = contents.iter()
 803                                             .map(|t| one(ty_to_type(ccx, t, any_changes_needed)))
 804                                             .collect::<Vec<_>>();
 805                         vec![Type::struct_(ccx, &elems, false)]
 806                     }
 807                     Aggregate(true, ref contents) => {
 808                         *any_changes_needed = true;
 809                         contents.iter()
 810                                 .flat_map(|t| ty_to_type(ccx, t, any_changes_needed))
 811                                 .collect()
 812                     }
 813                 }
 814             }
 815
 816             // This allows an argument list like `foo, (bar, baz),
 817             // qux` to be converted into `foo, bar, baz, qux`, integer
 818             // arguments to be truncated as needed and pointers to be
 819             // cast.
 820             fn modify_as_needed<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
 821                                             t: &intrinsics::Type,
 822                                             arg_type: Ty<'tcx>,
 823                                             llarg: ValueRef)
 824                                             -> Vec<ValueRef>
 825             {
 826                 match *t {
 827                     intrinsics::Type::Aggregate(true, ref contents) => {
 828                         // We found a tuple that needs squishing! So
 829                         // run over the tuple and load each field.
 830                         //
 831                         // This assumes the type is "simple", i.e. no
 832                         // destructors, and the contents are SIMD
 833                         // etc.
 834                         assert!(!bcx.fcx.type_needs_drop(arg_type));
 835
 836                         let repr = adt::represent_type(bcx.ccx(), arg_type);
 837                         let repr_ptr = &repr;
 838                         let arg = adt::MaybeSizedValue::sized(llarg);
 839                         (0..contents.len())
 840                             .map(|i| {
 841                                 Load(bcx, adt::trans_field_ptr(bcx, repr_ptr, arg, Disr(0), i))
 842                             })
 843                             .collect()
 844                     }
 845                     intrinsics::Type::Pointer(_, Some(ref llvm_elem), _) => {
 846                         let llvm_elem = one(ty_to_type(bcx.ccx(), llvm_elem, &mut false));
 847                         vec![PointerCast(bcx, llarg,
 848                                          llvm_elem.ptr_to())]
 849                     }
 850                     intrinsics::Type::Vector(_, Some(ref llvm_elem), length) => {
 851                         let llvm_elem = one(ty_to_type(bcx.ccx(), llvm_elem, &mut false));
 852                         vec![BitCast(bcx, llarg,
 853                                      Type::vector(&llvm_elem, length as u64))]
 854                     }
 855                     intrinsics::Type::Integer(_, width, llvm_width) if width != llvm_width => {
 856                         // the LLVM intrinsic uses a smaller integer
 857                         // size than the C intrinsic's signature, so
 858                         // we have to trim it down here.
 859                         vec![Trunc(bcx, llarg, Type::ix(bcx.ccx(), llvm_width as u64))]
 860                     }
 861                     _ => vec![llarg],
 862                 }
 863             }
 864
 865
 866             let mut any_changes_needed = false;
 867             let inputs = intr.inputs.iter()
 868                                     .flat_map(|t| ty_to_type(ccx, t, &mut any_changes_needed))
 869                                     .collect::<Vec<_>>();
 870
 871             let mut out_changes = false;
 872             let outputs = one(ty_to_type(ccx, &intr.output, &mut out_changes));
 873             // outputting a flattened aggregate is nonsense
 874             assert!(!out_changes);
 875
 876             let llargs = if !any_changes_needed {
 877                 // no aggregates to flatten, so no change needed
 878                 llargs
 879             } else {
 880                 // there are some aggregates that need to be flattened
 881                 // in the LLVM call, so we need to run over the types
 882                 // again to find them and extract the arguments
 883                 intr.inputs.iter()
 884                            .zip(&llargs)
 885                            .zip(&arg_tys)
 886                            .flat_map(|((t, llarg), ty)| modify_as_needed(bcx, t, ty, *llarg))
 887                            .collect()
 888             };
 889             assert_eq!(inputs.len(), llargs.len());
 890
 891             let val = match intr.definition {
 892                 intrinsics::IntrinsicDef::Named(name) => {
 893                     let f = declare::declare_cfn(ccx,
 894                                                  name,
 895                                                  Type::func(&inputs, &outputs));
 896                     Call(bcx, f, &llargs, call_debug_location)
 897                 }
 898             };
 899
 900             match *intr.output {
 901                 intrinsics::Type::Aggregate(flatten, ref elems) => {
 902                     // the output is a tuple so we need to munge it properly
 903                     assert!(!flatten);
 904
 905                     for i in 0..elems.len() {
 906                         let val = ExtractValue(bcx, val, i);
 907                         Store(bcx, val, StructGEP(bcx, llresult, i));
 908                     }
 909                     C_nil(ccx)
 910                 }
 911                 _ => val,
 912             }
 913         }
 914     };
 915
 916     if val_ty(llval) != Type::void(ccx) &&
 917        machine::llsize_of_alloc(ccx, val_ty(llval)) != 0 {
 918         if let Some(ty) = fn_ty.ret.cast {
 919             let ptr = PointerCast(bcx, llresult, ty.ptr_to());
 920             let store = Store(bcx, llval, ptr);
 921             unsafe {
 922                 llvm::LLVMSetAlignment(store, type_of::align_of(ccx, ret_ty));
 923             }
 924         } else {
 925             store_ty(bcx, llval, llresult, ret_ty);
 926         }
 927     }
 928
 929     // If we made a temporary stack slot, let's clean it up
 930     match dest {
 931         expr::Ignore => {
 932             bcx = glue::drop_ty(bcx, llresult, ret_ty, call_debug_location);
 933             call_lifetime_end(bcx, llresult);
 934         }
 935         expr::SaveIn(_) => {}
 936     }
 937
 938     fcx.pop_and_trans_custom_cleanup_scope(bcx, cleanup_scope);
 939
 940     Result::new(bcx, llresult)
 941 }
 942
 943 fn copy_intrinsic<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
 944                               allow_overlap: bool,
 945                               volatile: bool,
 946                               tp_ty: Ty<'tcx>,
 947                               dst: ValueRef,
 948                               src: ValueRef,
 949                               count: ValueRef,
 950                               call_debug_location: DebugLoc)
 951                               -> ValueRef {
 952     let ccx = bcx.ccx();
 953     let lltp_ty = type_of::type_of(ccx, tp_ty);
 954     let align = C_i32(ccx, type_of::align_of(ccx, tp_ty) as i32);
 955     let size = machine::llsize_of(ccx, lltp_ty);
 956     let int_size = machine::llbitsize_of_real(ccx, ccx.int_type());
 957
 958     let operation = if allow_overlap {
 959         "memmove"
 960     } else {
 961         "memcpy"
 962     };
 963
 964     let name = format!("llvm.{}.p0i8.p0i8.i{}", operation, int_size);
 965
 966     let dst_ptr = PointerCast(bcx, dst, Type::i8p(ccx));
 967     let src_ptr = PointerCast(bcx, src, Type::i8p(ccx));
 968     let llfn = ccx.get_intrinsic(&name);
 969
 970     Call(bcx,
 971          llfn,
 972          &[dst_ptr,
 973            src_ptr,
 974            Mul(bcx, size, count, DebugLoc::None),
 975            align,
 976            C_bool(ccx, volatile)],
 977          call_debug_location)
 978 }
 979
 980 fn memset_intrinsic<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
 981                                 volatile: bool,
 982                                 tp_ty: Ty<'tcx>,
 983                                 dst: ValueRef,
 984                                 val: ValueRef,
 985                                 count: ValueRef,
 986                                 call_debug_location: DebugLoc)
 987                                 -> ValueRef {
 988     let ccx = bcx.ccx();
 989     let lltp_ty = type_of::type_of(ccx, tp_ty);
 990     let align = C_i32(ccx, type_of::align_of(ccx, tp_ty) as i32);
 991     let size = machine::llsize_of(ccx, lltp_ty);
 992     let int_size = machine::llbitsize_of_real(ccx, ccx.int_type());
 993
 994     let name = format!("llvm.memset.p0i8.i{}", int_size);
 995
 996     let dst_ptr = PointerCast(bcx, dst, Type::i8p(ccx));
 997     let llfn = ccx.get_intrinsic(&name);
 998
 999     Call(bcx,
1000          llfn,
1001          &[dst_ptr,
1002            val,
1003            Mul(bcx, size, count, DebugLoc::None),
1004            align,
1005            C_bool(ccx, volatile)],
1006          call_debug_location)
1007 }
1008
1009 fn count_zeros_intrinsic(bcx: Block,
1010                          name: &str,
1011                          val: ValueRef,
1012                          call_debug_location: DebugLoc)
1013                          -> ValueRef {
1014     let y = C_bool(bcx.ccx(), false);
1015     let llfn = bcx.ccx().get_intrinsic(&name);
1016     Call(bcx, llfn, &[val, y], call_debug_location)
1017 }
1018
1019 fn with_overflow_intrinsic<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1020                                        name: &str,
1021                                        a: ValueRef,
1022                                        b: ValueRef,
1023                                        out: ValueRef,
1024                                        call_debug_location: DebugLoc)
1025                                        -> ValueRef {
1026     let llfn = bcx.ccx().get_intrinsic(&name);
1027
1028     // Convert `i1` to a `bool`, and write it to the out parameter
1029     let val = Call(bcx, llfn, &[a, b], call_debug_location);
1030     let result = ExtractValue(bcx, val, 0);
1031     let overflow = ZExt(bcx, ExtractValue(bcx, val, 1), Type::bool(bcx.ccx()));
1032     Store(bcx, result, StructGEP(bcx, out, 0));
1033     Store(bcx, overflow, StructGEP(bcx, out, 1));
1034
1035     C_nil(bcx.ccx())
1036 }
1037
1038 fn try_intrinsic<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1039                              func: ValueRef,
1040                              data: ValueRef,
1041                              local_ptr: ValueRef,
1042                              dest: ValueRef,
1043                              dloc: DebugLoc) -> Block<'blk, 'tcx> {
1044     if bcx.sess().no_landing_pads() {
1045         Call(bcx, func, &[data], dloc);
1046         Store(bcx, C_null(Type::i8p(bcx.ccx())), dest);
1047         bcx
1048     } else if wants_msvc_seh(bcx.sess()) {
1049         trans_msvc_try(bcx, func, data, local_ptr, dest, dloc)
1050     } else {
1051         trans_gnu_try(bcx, func, data, local_ptr, dest, dloc)
1052     }
1053 }
1054
1055 // MSVC's definition of the `rust_try` function.
1056 //
1057 // This implementation uses the new exception handling instructions in LLVM
1058 // which have support in LLVM for SEH on MSVC targets. Although these
1059 // instructions are meant to work for all targets, as of the time of this
1060 // writing, however, LLVM does not recommend the usage of these new instructions
1061 // as the old ones are still more optimized.
1062 fn trans_msvc_try<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1063                               func: ValueRef,
1064                               data: ValueRef,
1065                               local_ptr: ValueRef,
1066                               dest: ValueRef,
1067                               dloc: DebugLoc) -> Block<'blk, 'tcx> {
1068     let llfn = get_rust_try_fn(bcx.fcx, &mut |bcx| {
1069         let ccx = bcx.ccx();
1070         let dloc = DebugLoc::None;
1071
1072         SetPersonalityFn(bcx, bcx.fcx.eh_personality());
1073
1074         let normal = bcx.fcx.new_temp_block("normal");
1075         let catchswitch = bcx.fcx.new_temp_block("catchswitch");
1076         let catchpad = bcx.fcx.new_temp_block("catchpad");
1077         let caught = bcx.fcx.new_temp_block("caught");
1078
1079         let func = llvm::get_param(bcx.fcx.llfn, 0);
1080         let data = llvm::get_param(bcx.fcx.llfn, 1);
1081         let local_ptr = llvm::get_param(bcx.fcx.llfn, 2);
1082
1083         // We're generating an IR snippet that looks like:
1084         //
1085         //   declare i32 @rust_try(%func, %data, %ptr) {
1086         //      %slot = alloca i64*
1087         //      invoke %func(%data) to label %normal unwind label %catchswitch
1088         //
1089         //   normal:
1090         //      ret i32 0
1091         //
1092         //   catchswitch:
1093         //      %cs = catchswitch within none [%catchpad] unwind to caller
1094         //
1095         //   catchpad:
1096         //      %tok = catchpad within %cs [%type_descriptor, 0, %slot]
1097         //      %ptr[0] = %slot[0]
1098         //      %ptr[1] = %slot[1]
1099         //      catchret from %tok to label %caught
1100         //
1101         //   caught:
1102         //      ret i32 1
1103         //   }
1104         //
1105         // This structure follows the basic usage of throw/try/catch in LLVM.
1106         // For example, compile this C++ snippet to see what LLVM generates:
1107         //
1108         //      #include <stdint.h>
1109         //
1110         //      int bar(void (*foo)(void), uint64_t *ret) {
1111         //          try {
1112         //              foo();
1113         //              return 0;
1114         //          } catch(uint64_t a[2]) {
1115         //              ret[0] = a[0];
1116         //              ret[1] = a[1];
1117         //              return 1;
1118         //          }
1119         //      }
1120         //
1121         // More information can be found in libstd's seh.rs implementation.
1122         let i64p = Type::i64(ccx).ptr_to();
1123         let slot = Alloca(bcx, i64p, "slot");
1124         Invoke(bcx, func, &[data], normal.llbb, catchswitch.llbb, dloc);
1125
1126         Ret(normal, C_i32(ccx, 0), dloc);
1127
1128         let cs = CatchSwitch(catchswitch, None, None, 1);
1129         AddHandler(catchswitch, cs, catchpad.llbb);
1130
1131         let tcx = ccx.tcx();
1132         let tydesc = match tcx.lang_items.msvc_try_filter() {
1133             Some(did) => ::consts::get_static(ccx, did).to_llref(),
1134             None => bug!("msvc_try_filter not defined"),
1135         };
1136         let tok = CatchPad(catchpad, cs, &[tydesc, C_i32(ccx, 0), slot]);
1137         let addr = Load(catchpad, slot);
1138         let arg1 = Load(catchpad, addr);
1139         let val1 = C_i32(ccx, 1);
1140         let arg2 = Load(catchpad, InBoundsGEP(catchpad, addr, &[val1]));
1141         let local_ptr = BitCast(catchpad, local_ptr, i64p);
1142         Store(catchpad, arg1, local_ptr);
1143         Store(catchpad, arg2, InBoundsGEP(catchpad, local_ptr, &[val1]));
1144         CatchRet(catchpad, tok, caught.llbb);
1145
1146         Ret(caught, C_i32(ccx, 1), dloc);
1147     });
1148
1149     // Note that no invoke is used here because by definition this function
1150     // can't panic (that's what it's catching).
1151     let ret = Call(bcx, llfn, &[func, data, local_ptr], dloc);
1152     Store(bcx, ret, dest);
1153     return bcx
1154 }
1155
1156 // Definition of the standard "try" function for Rust using the GNU-like model
1157 // of exceptions (e.g. the normal semantics of LLVM's landingpad and invoke
1158 // instructions).
1159 //
1160 // This translation is a little surprising because we always call a shim
1161 // function instead of inlining the call to `invoke` manually here. This is done
1162 // because in LLVM we're only allowed to have one personality per function
1163 // definition. The call to the `try` intrinsic is being inlined into the
1164 // function calling it, and that function may already have other personality
1165 // functions in play. By calling a shim we're guaranteed that our shim will have
1166 // the right personality function.
1167 fn trans_gnu_try<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1168                              func: ValueRef,
1169                              data: ValueRef,
1170                              local_ptr: ValueRef,
1171                              dest: ValueRef,
1172                              dloc: DebugLoc) -> Block<'blk, 'tcx> {
1173     let llfn = get_rust_try_fn(bcx.fcx, &mut |bcx| {
1174         let ccx = bcx.ccx();
1175         let tcx = ccx.tcx();
1176         let dloc = DebugLoc::None;
1177
1178         // Translates the shims described above:
1179         //
1180         //   bcx:
1181         //      invoke %func(%args...) normal %normal unwind %catch
1182         //
1183         //   normal:
1184         //      ret 0
1185         //
1186         //   catch:
1187         //      (ptr, _) = landingpad
1188         //      store ptr, %local_ptr
1189         //      ret 1
1190         //
1191         // Note that the `local_ptr` data passed into the `try` intrinsic is
1192         // expected to be `*mut *mut u8` for this to actually work, but that's
1193         // managed by the standard library.
1194
1195         attributes::emit_uwtable(bcx.fcx.llfn, true);
1196         let catch_pers = match tcx.lang_items.eh_personality_catch() {
1197             Some(did) => {
1198                 Callee::def(ccx, did, tcx.mk_substs(Substs::empty())).reify(ccx).val
1199             }
1200             None => bug!("eh_personality_catch not defined"),
1201         };
1202
1203         let then = bcx.fcx.new_temp_block("then");
1204         let catch = bcx.fcx.new_temp_block("catch");
1205
1206         let func = llvm::get_param(bcx.fcx.llfn, 0);
1207         let data = llvm::get_param(bcx.fcx.llfn, 1);
1208         let local_ptr = llvm::get_param(bcx.fcx.llfn, 2);
1209         Invoke(bcx, func, &[data], then.llbb, catch.llbb, dloc);
1210         Ret(then, C_i32(ccx, 0), dloc);
1211
1212         // Type indicator for the exception being thrown.
1213         //
1214         // The first value in this tuple is a pointer to the exception object
1215         // being thrown.  The second value is a "selector" indicating which of
1216         // the landing pad clauses the exception's type had been matched to.
1217         // rust_try ignores the selector.
1218         let lpad_ty = Type::struct_(ccx, &[Type::i8p(ccx), Type::i32(ccx)],
1219                                     false);
1220         let vals = LandingPad(catch, lpad_ty, catch_pers, 1);
1221         AddClause(catch, vals, C_null(Type::i8p(ccx)));
1222         let ptr = ExtractValue(catch, vals, 0);
1223         Store(catch, ptr, BitCast(catch, local_ptr, Type::i8p(ccx).ptr_to()));
1224         Ret(catch, C_i32(ccx, 1), dloc);
1225     });
1226
1227     // Note that no invoke is used here because by definition this function
1228     // can't panic (that's what it's catching).
1229     let ret = Call(bcx, llfn, &[func, data, local_ptr], dloc);
1230     Store(bcx, ret, dest);
1231     return bcx;
1232 }
1233
1234 // Helper function to give a Block to a closure to translate a shim function.
1235 // This is currently primarily used for the `try` intrinsic functions above.
1236 fn gen_fn<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
1237                     name: &str,
1238                     inputs: Vec<Ty<'tcx>>,
1239                     output: ty::FnOutput<'tcx>,
1240                     trans: &mut for<'b> FnMut(Block<'b, 'tcx>))
1241                     -> ValueRef {
1242     let ccx = fcx.ccx;
1243     let sig = ty::FnSig {
1244         inputs: inputs,
1245         output: output,
1246         variadic: false,
1247     };
1248     let fn_ty = FnType::new(ccx, Abi::Rust, &sig, &[]);
1249
1250     let rust_fn_ty = ccx.tcx().mk_fn_ptr(ccx.tcx().mk_bare_fn(ty::BareFnTy {
1251         unsafety: hir::Unsafety::Unsafe,
1252         abi: Abi::Rust,
1253         sig: ty::Binder(sig)
1254     }));
1255     let llfn = declare::define_internal_fn(ccx, name, rust_fn_ty);
1256     let (fcx, block_arena);
1257     block_arena = TypedArena::new();
1258     fcx = FunctionContext::new(ccx, llfn, fn_ty, None, &block_arena);
1259     let bcx = fcx.init(true, None);
1260     trans(bcx);
1261     fcx.cleanup();
1262     llfn
1263 }
1264
1265 // Helper function used to get a handle to the `__rust_try` function used to
1266 // catch exceptions.
1267 //
1268 // This function is only generated once and is then cached.
1269 fn get_rust_try_fn<'a, 'tcx>(fcx: &FunctionContext<'a, 'tcx>,
1270                              trans: &mut for<'b> FnMut(Block<'b, 'tcx>))
1271                              -> ValueRef {
1272     let ccx = fcx.ccx;
1273     if let Some(llfn) = ccx.rust_try_fn().get() {
1274         return llfn;
1275     }
1276
1277     // Define the type up front for the signature of the rust_try function.
1278     let tcx = ccx.tcx();
1279     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
1280     let fn_ty = tcx.mk_fn_ptr(tcx.mk_bare_fn(ty::BareFnTy {
1281         unsafety: hir::Unsafety::Unsafe,
1282         abi: Abi::Rust,
1283         sig: ty::Binder(ty::FnSig {
1284             inputs: vec![i8p],
1285             output: ty::FnOutput::FnConverging(tcx.mk_nil()),
1286             variadic: false,
1287         }),
1288     }));
1289     let output = ty::FnOutput::FnConverging(tcx.types.i32);
1290     let rust_try = gen_fn(fcx, "__rust_try", vec![fn_ty, i8p, i8p], output, trans);
1291     ccx.rust_try_fn().set(Some(rust_try));
1292     return rust_try
1293 }
1294
1295 fn span_invalid_monomorphization_error(a: &Session, b: Span, c: &str) {
1296     span_err!(a, b, E0511, "{}", c);
1297 }
1298
1299 fn generic_simd_intrinsic<'blk, 'tcx, 'a>
1300     (bcx: Block<'blk, 'tcx>,
1301      name: &str,
1302      substs: &'tcx subst::Substs<'tcx>,
1303      callee_ty: Ty<'tcx>,
1304      args: Option<&[P<hir::Expr>]>,
1305      llargs: &[ValueRef],
1306      ret_ty: Ty<'tcx>,
1307      llret_ty: Type,
1308      call_debug_location: DebugLoc,
1309      span: Span) -> ValueRef
1310 {
1311     // macros for error handling:
1312     macro_rules! emit_error {
1313         ($msg: tt) => {
1314             emit_error!($msg, )
1315         };
1316         ($msg: tt, $($fmt: tt)*) => {
1317             span_invalid_monomorphization_error(
1318                 bcx.sess(), span,
1319                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ",
1320                                  $msg),
1321                          name, $($fmt)*));
1322         }
1323     }
1324     macro_rules! require {
1325         ($cond: expr, $($fmt: tt)*) => {
1326             if !$cond {
1327                 emit_error!($($fmt)*);
1328                 return C_nil(bcx.ccx())
1329             }
1330         }
1331     }
1332     macro_rules! require_simd {
1333         ($ty: expr, $position: expr) => {
1334             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
1335         }
1336     }
1337
1338
1339
1340     let tcx = bcx.tcx();
1341     let sig = tcx.erase_late_bound_regions(callee_ty.fn_sig());
1342     let sig = tcx.normalize_associated_type(&sig);
1343     let arg_tys = sig.inputs;
1344
1345     // every intrinsic takes a SIMD vector as its first argument
1346     require_simd!(arg_tys[0], "input");
1347     let in_ty = arg_tys[0];
1348     let in_elem = arg_tys[0].simd_type(tcx);
1349     let in_len = arg_tys[0].simd_size(tcx);
1350
1351     let comparison = match name {
1352         "simd_eq" => Some(hir::BiEq),
1353         "simd_ne" => Some(hir::BiNe),
1354         "simd_lt" => Some(hir::BiLt),
1355         "simd_le" => Some(hir::BiLe),
1356         "simd_gt" => Some(hir::BiGt),
1357         "simd_ge" => Some(hir::BiGe),
1358         _ => None
1359     };
1360
1361     if let Some(cmp_op) = comparison {
1362         require_simd!(ret_ty, "return");
1363
1364         let out_len = ret_ty.simd_size(tcx);
1365         require!(in_len == out_len,
1366                  "expected return type with length {} (same as input type `{}`), \
1367                   found `{}` with length {}",
1368                  in_len, in_ty,
1369                  ret_ty, out_len);
1370         require!(llret_ty.element_type().kind() == llvm::Integer,
1371                  "expected return type with integer elements, found `{}` with non-integer `{}`",
1372                  ret_ty,
1373                  ret_ty.simd_type(tcx));
1374
1375         return compare_simd_types(bcx,
1376                                   llargs[0],
1377                                   llargs[1],
1378                                   in_elem,
1379                                   llret_ty,
1380                                   cmp_op,
1381                                   call_debug_location)
1382     }
1383
1384     if name.starts_with("simd_shuffle") {
1385         let n: usize = match name["simd_shuffle".len()..].parse() {
1386             Ok(n) => n,
1387             Err(_) => span_bug!(span,
1388                                 "bad `simd_shuffle` instruction only caught in trans?")
1389         };
1390
1391         require_simd!(ret_ty, "return");
1392
1393         let out_len = ret_ty.simd_size(tcx);
1394         require!(out_len == n,
1395                  "expected return type of length {}, found `{}` with length {}",
1396                  n, ret_ty, out_len);
1397         require!(in_elem == ret_ty.simd_type(tcx),
1398                  "expected return element type `{}` (element of input `{}`), \
1399                   found `{}` with element type `{}`",
1400                  in_elem, in_ty,
1401                  ret_ty, ret_ty.simd_type(tcx));
1402
1403         let total_len = in_len as u64 * 2;
1404
1405         let vector = match args {
1406             Some(args) => {
1407                 match consts::const_expr(bcx.ccx(), &args[2], substs, None,
1408                                          // this should probably help simd error reporting
1409                                          consts::TrueConst::Yes) {
1410                     Ok((vector, _)) => vector,
1411                     Err(err) => bcx.sess().span_fatal(span, &err.description()),
1412                 }
1413             }
1414             None => llargs[2]
1415         };
1416
1417         let indices: Option<Vec<_>> = (0..n)
1418             .map(|i| {
1419                 let arg_idx = i;
1420                 let val = const_get_elt(vector, &[i as libc::c_uint]);
1421                 match const_to_opt_uint(val) {
1422                     None => {
1423                         emit_error!("shuffle index #{} is not a constant", arg_idx);
1424                         None
1425                     }
1426                     Some(idx) if idx >= total_len => {
1427                         emit_error!("shuffle index #{} is out of bounds (limit {})",
1428                                     arg_idx, total_len);
1429                         None
1430                     }
1431                     Some(idx) => Some(C_i32(bcx.ccx(), idx as i32)),
1432                 }
1433             })
1434             .collect();
1435         let indices = match indices {
1436             Some(i) => i,
1437             None => return C_null(llret_ty)
1438         };
1439
1440         return ShuffleVector(bcx, llargs[0], llargs[1], C_vector(&indices))
1441     }
1442
1443     if name == "simd_insert" {
1444         require!(in_elem == arg_tys[2],
1445                  "expected inserted type `{}` (element of input `{}`), found `{}`",
1446                  in_elem, in_ty, arg_tys[2]);
1447         return InsertElement(bcx, llargs[0], llargs[2], llargs[1])
1448     }
1449     if name == "simd_extract" {
1450         require!(ret_ty == in_elem,
1451                  "expected return type `{}` (element of input `{}`), found `{}`",
1452                  in_elem, in_ty, ret_ty);
1453         return ExtractElement(bcx, llargs[0], llargs[1])
1454     }
1455
1456     if name == "simd_cast" {
1457         require_simd!(ret_ty, "return");
1458         let out_len = ret_ty.simd_size(tcx);
1459         require!(in_len == out_len,
1460                  "expected return type with length {} (same as input type `{}`), \
1461                   found `{}` with length {}",
1462                  in_len, in_ty,
1463                  ret_ty, out_len);
1464         // casting cares about nominal type, not just structural type
1465         let out_elem = ret_ty.simd_type(tcx);
1466
1467         if in_elem == out_elem { return llargs[0]; }
1468
1469         enum Style { Float, Int(/* is signed? */ bool), Unsupported }
1470
1471         let (in_style, in_width) = match in_elem.sty {
1472             // vectors of pointer-sized integers should've been
1473             // disallowed before here, so this unwrap is safe.
1474             ty::TyInt(i) => (Style::Int(true), i.bit_width().unwrap()),
1475             ty::TyUint(u) => (Style::Int(false), u.bit_width().unwrap()),
1476             ty::TyFloat(f) => (Style::Float, f.bit_width()),
1477             _ => (Style::Unsupported, 0)
1478         };
1479         let (out_style, out_width) = match out_elem.sty {
1480             ty::TyInt(i) => (Style::Int(true), i.bit_width().unwrap()),
1481             ty::TyUint(u) => (Style::Int(false), u.bit_width().unwrap()),
1482             ty::TyFloat(f) => (Style::Float, f.bit_width()),
1483             _ => (Style::Unsupported, 0)
1484         };
1485
1486         match (in_style, out_style) {
1487             (Style::Int(in_is_signed), Style::Int(_)) => {
1488                 return match in_width.cmp(&out_width) {
1489                     Ordering::Greater => Trunc(bcx, llargs[0], llret_ty),
1490                     Ordering::Equal => llargs[0],
1491                     Ordering::Less => if in_is_signed {
1492                         SExt(bcx, llargs[0], llret_ty)
1493                     } else {
1494                         ZExt(bcx, llargs[0], llret_ty)
1495                     }
1496                 }
1497             }
1498             (Style::Int(in_is_signed), Style::Float) => {
1499                 return if in_is_signed {
1500                     SIToFP(bcx, llargs[0], llret_ty)
1501                 } else {
1502                     UIToFP(bcx, llargs[0], llret_ty)
1503                 }
1504             }
1505             (Style::Float, Style::Int(out_is_signed)) => {
1506                 return if out_is_signed {
1507                     FPToSI(bcx, llargs[0], llret_ty)
1508                 } else {
1509                     FPToUI(bcx, llargs[0], llret_ty)
1510                 }
1511             }
1512             (Style::Float, Style::Float) => {
1513                 return match in_width.cmp(&out_width) {
1514                     Ordering::Greater => FPTrunc(bcx, llargs[0], llret_ty),
1515                     Ordering::Equal => llargs[0],
1516                     Ordering::Less => FPExt(bcx, llargs[0], llret_ty)
1517                 }
1518             }
1519             _ => {/* Unsupported. Fallthrough. */}
1520         }
1521         require!(false,
1522                  "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
1523                  in_ty, in_elem,
1524                  ret_ty, out_elem);
1525     }
1526     macro_rules! arith {
1527         ($($name: ident: $($($p: ident),* => $call: expr),*;)*) => {
1528             $(
1529                 if name == stringify!($name) {
1530                     match in_elem.sty {
1531                         $(
1532                             $(ty::$p(_))|* => {
1533                                 return $call(bcx, llargs[0], llargs[1], call_debug_location)
1534                             }
1535                             )*
1536                         _ => {},
1537                     }
1538                     require!(false,
1539                              "unsupported operation on `{}` with element `{}`",
1540                              in_ty,
1541                              in_elem)
1542                 })*
1543         }
1544     }
1545     arith! {
1546         simd_add: TyUint, TyInt => Add, TyFloat => FAdd;
1547         simd_sub: TyUint, TyInt => Sub, TyFloat => FSub;
1548         simd_mul: TyUint, TyInt => Mul, TyFloat => FMul;
1549         simd_div: TyFloat => FDiv;
1550         simd_shl: TyUint, TyInt => Shl;
1551         simd_shr: TyUint => LShr, TyInt => AShr;
1552         simd_and: TyUint, TyInt => And;
1553         simd_or: TyUint, TyInt => Or;
1554         simd_xor: TyUint, TyInt => Xor;
1555     }
1556     span_bug!(span, "unknown SIMD intrinsic");
1557 }
1558
1559 // Returns the width of an int TypeVariant, and if it's signed or not
1560 // Returns None if the type is not an integer
1561 fn int_type_width_signed<'tcx>(sty: &ty::TypeVariants<'tcx>, ccx: &CrateContext)
1562         -> Option<(u64, bool)> {
1563     use rustc::ty::{TyInt, TyUint};
1564     match *sty {
1565         TyInt(t) => Some((match t {
1566             ast::IntTy::Is => {
1567                 match &ccx.tcx().sess.target.target.target_pointer_width[..] {
1568                     "16" => 16,
1569                     "32" => 32,
1570                     "64" => 64,
1571                     tws => bug!("Unsupported target word size for isize: {}", tws),
1572                 }
1573             },
1574             ast::IntTy::I8 => 8,
1575             ast::IntTy::I16 => 16,
1576             ast::IntTy::I32 => 32,
1577             ast::IntTy::I64 => 64,
1578         }, true)),
1579         TyUint(t) => Some((match t {
1580             ast::UintTy::Us => {
1581                 match &ccx.tcx().sess.target.target.target_pointer_width[..] {
1582                     "16" => 16,
1583                     "32" => 32,
1584                     "64" => 64,
1585                     tws => bug!("Unsupported target word size for usize: {}", tws),
1586                 }
1587             },
1588             ast::UintTy::U8 => 8,
1589             ast::UintTy::U16 => 16,
1590             ast::UintTy::U32 => 32,
1591             ast::UintTy::U64 => 64,
1592         }, false)),
1593         _ => None,
1594     }
1595 }
1596
1597 // Returns the width of a float TypeVariant
1598 // Returns None if the type is not a float
1599 fn float_type_width<'tcx>(sty: &ty::TypeVariants<'tcx>)
1600         -> Option<u64> {
1601     use rustc::ty::TyFloat;
1602     match *sty {
1603         TyFloat(t) => Some(match t {
1604             ast::FloatTy::F32 => 32,
1605             ast::FloatTy::F64 => 64,
1606         }),
1607         _ => None,
1608     }
1609 }