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 intrinsics::{self, Intrinsic};
  14 use llvm;
  15 use llvm::{ValueRef};
  16 use abi::{Abi, FnType, PassMode};
  17 use mir::place::PlaceRef;
  18 use mir::operand::{OperandRef, OperandValue};
  19 use base::*;
  20 use common::*;
  21 use declare;
  22 use glue;
  23 use type_::Type;
  24 use type_of::LayoutLlvmExt;
  25 use rustc::ty::{self, Ty};
  26 use rustc::ty::layout::{HasDataLayout, LayoutOf};
  27 use rustc::hir;
  28 use syntax::ast;
  29 use syntax::symbol::Symbol;
  30 use builder::Builder;
  31
  32 use rustc::session::Session;
  33 use syntax_pos::Span;
  34
  35 use std::cmp::Ordering;
  36 use std::iter;
  37
  38 fn get_simple_intrinsic(cx: &CodegenCx, name: &str) -> Option<ValueRef> {
  39     let llvm_name = match name {
  40         "sqrtf32" => "llvm.sqrt.f32",
  41         "sqrtf64" => "llvm.sqrt.f64",
  42         "powif32" => "llvm.powi.f32",
  43         "powif64" => "llvm.powi.f64",
  44         "sinf32" => "llvm.sin.f32",
  45         "sinf64" => "llvm.sin.f64",
  46         "cosf32" => "llvm.cos.f32",
  47         "cosf64" => "llvm.cos.f64",
  48         "powf32" => "llvm.pow.f32",
  49         "powf64" => "llvm.pow.f64",
  50         "expf32" => "llvm.exp.f32",
  51         "expf64" => "llvm.exp.f64",
  52         "exp2f32" => "llvm.exp2.f32",
  53         "exp2f64" => "llvm.exp2.f64",
  54         "logf32" => "llvm.log.f32",
  55         "logf64" => "llvm.log.f64",
  56         "log10f32" => "llvm.log10.f32",
  57         "log10f64" => "llvm.log10.f64",
  58         "log2f32" => "llvm.log2.f32",
  59         "log2f64" => "llvm.log2.f64",
  60         "fmaf32" => "llvm.fma.f32",
  61         "fmaf64" => "llvm.fma.f64",
  62         "fabsf32" => "llvm.fabs.f32",
  63         "fabsf64" => "llvm.fabs.f64",
  64         "copysignf32" => "llvm.copysign.f32",
  65         "copysignf64" => "llvm.copysign.f64",
  66         "floorf32" => "llvm.floor.f32",
  67         "floorf64" => "llvm.floor.f64",
  68         "ceilf32" => "llvm.ceil.f32",
  69         "ceilf64" => "llvm.ceil.f64",
  70         "truncf32" => "llvm.trunc.f32",
  71         "truncf64" => "llvm.trunc.f64",
  72         "rintf32" => "llvm.rint.f32",
  73         "rintf64" => "llvm.rint.f64",
  74         "nearbyintf32" => "llvm.nearbyint.f32",
  75         "nearbyintf64" => "llvm.nearbyint.f64",
  76         "roundf32" => "llvm.round.f32",
  77         "roundf64" => "llvm.round.f64",
  78         "assume" => "llvm.assume",
  79         "abort" => "llvm.trap",
  80         _ => return None
  81     };
  82     Some(cx.get_intrinsic(&llvm_name))
  83 }
  84
  85 /// Remember to add all intrinsics here, in librustc_typeck/check/mod.rs,
  86 /// and in libcore/intrinsics.rs; if you need access to any llvm intrinsics,
  87 /// add them to librustc_trans/trans/context.rs
  88 pub fn trans_intrinsic_call<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
  89                                       callee_ty: Ty<'tcx>,
  90                                       fn_ty: &FnType<'tcx>,
  91                                       args: &[OperandRef<'tcx>],
  92                                       llresult: ValueRef,
  93                                       span: Span) {
  94     let cx = bx.cx;
  95     let tcx = cx.tcx;
  96
  97     let (def_id, substs) = match callee_ty.sty {
  98         ty::TyFnDef(def_id, substs) => (def_id, substs),
  99         _ => bug!("expected fn item type, found {}", callee_ty)
 100     };
 101
 102     let sig = callee_ty.fn_sig(tcx);
 103     let sig = tcx.erase_late_bound_regions_and_normalize(&sig);
 104     let arg_tys = sig.inputs();
 105     let ret_ty = sig.output();
 106     let name = &*tcx.item_name(def_id);
 107
 108     let llret_ty = cx.layout_of(ret_ty).llvm_type(cx);
 109     let result = PlaceRef::new_sized(llresult, fn_ty.ret.layout, fn_ty.ret.layout.align);
 110
 111     let simple = get_simple_intrinsic(cx, name);
 112     let llval = match name {
 113         _ if simple.is_some() => {
 114             bx.call(simple.unwrap(),
 115                      &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 116                      None)
 117         }
 118         "unreachable" => {
 119             return;
 120         },
 121         "likely" => {
 122             let expect = cx.get_intrinsic(&("llvm.expect.i1"));
 123             bx.call(expect, &[args[0].immediate(), C_bool(cx, true)], None)
 124         }
 125         "unlikely" => {
 126             let expect = cx.get_intrinsic(&("llvm.expect.i1"));
 127             bx.call(expect, &[args[0].immediate(), C_bool(cx, false)], None)
 128         }
 129         "try" => {
 130             try_intrinsic(bx, cx,
 131                           args[0].immediate(),
 132                           args[1].immediate(),
 133                           args[2].immediate(),
 134                           llresult);
 135             return;
 136         }
 137         "breakpoint" => {
 138             let llfn = cx.get_intrinsic(&("llvm.debugtrap"));
 139             bx.call(llfn, &[], None)
 140         }
 141         "size_of" => {
 142             let tp_ty = substs.type_at(0);
 143             C_usize(cx, cx.size_of(tp_ty).bytes())
 144         }
 145         "size_of_val" => {
 146             let tp_ty = substs.type_at(0);
 147             if let OperandValue::Pair(_, meta) = args[0].val {
 148                 let (llsize, _) =
 149                     glue::size_and_align_of_dst(bx, tp_ty, meta);
 150                 llsize
 151             } else {
 152                 C_usize(cx, cx.size_of(tp_ty).bytes())
 153             }
 154         }
 155         "min_align_of" => {
 156             let tp_ty = substs.type_at(0);
 157             C_usize(cx, cx.align_of(tp_ty).abi())
 158         }
 159         "min_align_of_val" => {
 160             let tp_ty = substs.type_at(0);
 161             if let OperandValue::Pair(_, meta) = args[0].val {
 162                 let (_, llalign) =
 163                     glue::size_and_align_of_dst(bx, tp_ty, meta);
 164                 llalign
 165             } else {
 166                 C_usize(cx, cx.align_of(tp_ty).abi())
 167             }
 168         }
 169         "pref_align_of" => {
 170             let tp_ty = substs.type_at(0);
 171             C_usize(cx, cx.align_of(tp_ty).pref())
 172         }
 173         "type_name" => {
 174             let tp_ty = substs.type_at(0);
 175             let ty_name = Symbol::intern(&tp_ty.to_string()).as_str();
 176             C_str_slice(cx, ty_name)
 177         }
 178         "type_id" => {
 179             C_u64(cx, cx.tcx.type_id_hash(substs.type_at(0)))
 180         }
 181         "init" => {
 182             let ty = substs.type_at(0);
 183             if !cx.layout_of(ty).is_zst() {
 184                 // Just zero out the stack slot.
 185                 // If we store a zero constant, LLVM will drown in vreg allocation for large data
 186                 // structures, and the generated code will be awful. (A telltale sign of this is
 187                 // large quantities of `mov [byte ptr foo],0` in the generated code.)
 188                 memset_intrinsic(bx, false, ty, llresult, C_u8(cx, 0), C_usize(cx, 1));
 189             }
 190             return;
 191         }
 192         // Effectively no-ops
 193         "uninit" => {
 194             return;
 195         }
 196         "needs_drop" => {
 197             let tp_ty = substs.type_at(0);
 198
 199             C_bool(cx, bx.cx.type_needs_drop(tp_ty))
 200         }
 201         "offset" => {
 202             let ptr = args[0].immediate();
 203             let offset = args[1].immediate();
 204             bx.inbounds_gep(ptr, &[offset])
 205         }
 206         "arith_offset" => {
 207             let ptr = args[0].immediate();
 208             let offset = args[1].immediate();
 209             bx.gep(ptr, &[offset])
 210         }
 211
 212         "copy_nonoverlapping" => {
 213             copy_intrinsic(bx, false, false, substs.type_at(0),
 214                            args[1].immediate(), args[0].immediate(), args[2].immediate())
 215         }
 216         "copy" => {
 217             copy_intrinsic(bx, true, false, substs.type_at(0),
 218                            args[1].immediate(), args[0].immediate(), args[2].immediate())
 219         }
 220         "write_bytes" => {
 221             memset_intrinsic(bx, false, substs.type_at(0),
 222                              args[0].immediate(), args[1].immediate(), args[2].immediate())
 223         }
 224
 225         "volatile_copy_nonoverlapping_memory" => {
 226             copy_intrinsic(bx, false, true, substs.type_at(0),
 227                            args[0].immediate(), args[1].immediate(), args[2].immediate())
 228         }
 229         "volatile_copy_memory" => {
 230             copy_intrinsic(bx, true, true, substs.type_at(0),
 231                            args[0].immediate(), args[1].immediate(), args[2].immediate())
 232         }
 233         "volatile_set_memory" => {
 234             memset_intrinsic(bx, true, substs.type_at(0),
 235                              args[0].immediate(), args[1].immediate(), args[2].immediate())
 236         }
 237         "volatile_load" => {
 238             let tp_ty = substs.type_at(0);
 239             let mut ptr = args[0].immediate();
 240             if let PassMode::Cast(ty) = fn_ty.ret.mode {
 241                 ptr = bx.pointercast(ptr, ty.llvm_type(cx).ptr_to());
 242             }
 243             let load = bx.volatile_load(ptr);
 244             unsafe {
 245                 llvm::LLVMSetAlignment(load, cx.align_of(tp_ty).abi() as u32);
 246             }
 247             to_immediate(bx, load, cx.layout_of(tp_ty))
 248         },
 249         "volatile_store" => {
 250             let tp_ty = substs.type_at(0);
 251             let dst = args[0].deref(bx.cx);
 252             if let OperandValue::Pair(a, b) = args[1].val {
 253                 bx.volatile_store(a, dst.project_field(bx, 0).llval);
 254                 bx.volatile_store(b, dst.project_field(bx, 1).llval);
 255             } else {
 256                 let val = if let OperandValue::Ref(ptr, align) = args[1].val {
 257                     bx.load(ptr, align)
 258                 } else {
 259                     if dst.layout.is_zst() {
 260                         return;
 261                     }
 262                     from_immediate(bx, args[1].immediate())
 263                 };
 264                 let ptr = bx.pointercast(dst.llval, val_ty(val).ptr_to());
 265                 let store = bx.volatile_store(val, ptr);
 266                 unsafe {
 267                     llvm::LLVMSetAlignment(store, cx.align_of(tp_ty).abi() as u32);
 268                 }
 269             }
 270             return;
 271         },
 272         "prefetch_read_data" | "prefetch_write_data" |
 273         "prefetch_read_instruction" | "prefetch_write_instruction" => {
 274             let expect = cx.get_intrinsic(&("llvm.prefetch"));
 275             let (rw, cache_type) = match name {
 276                 "prefetch_read_data" => (0, 1),
 277                 "prefetch_write_data" => (1, 1),
 278                 "prefetch_read_instruction" => (0, 0),
 279                 "prefetch_write_instruction" => (1, 0),
 280                 _ => bug!()
 281             };
 282             bx.call(expect, &[
 283                 args[0].immediate(),
 284                 C_i32(cx, rw),
 285                 args[1].immediate(),
 286                 C_i32(cx, cache_type)
 287             ], None)
 288         },
 289         "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap" |
 290         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" |
 291         "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
 292         "unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" => {
 293             let ty = arg_tys[0];
 294             match int_type_width_signed(ty, cx) {
 295                 Some((width, signed)) =>
 296                     match name {
 297                         "ctlz" | "cttz" => {
 298                             let y = C_bool(bx.cx, false);
 299                             let llfn = cx.get_intrinsic(&format!("llvm.{}.i{}", name, width));
 300                             bx.call(llfn, &[args[0].immediate(), y], None)
 301                         }
 302                         "ctlz_nonzero" | "cttz_nonzero" => {
 303                             let y = C_bool(bx.cx, true);
 304                             let llvm_name = &format!("llvm.{}.i{}", &name[..4], width);
 305                             let llfn = cx.get_intrinsic(llvm_name);
 306                             bx.call(llfn, &[args[0].immediate(), y], None)
 307                         }
 308                         "ctpop" => bx.call(cx.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 309                                         &[args[0].immediate()], None),
 310                         "bswap" => {
 311                             if width == 8 {
 312                                 args[0].immediate() // byte swap a u8/i8 is just a no-op
 313                             } else {
 314                                 bx.call(cx.get_intrinsic(&format!("llvm.bswap.i{}", width)),
 315                                         &[args[0].immediate()], None)
 316                             }
 317                         }
 318                         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" => {
 319                             let intrinsic = format!("llvm.{}{}.with.overflow.i{}",
 320                                                     if signed { 's' } else { 'u' },
 321                                                     &name[..3], width);
 322                             let llfn = bx.cx.get_intrinsic(&intrinsic);
 323
 324                             // Convert `i1` to a `bool`, and write it to the out parameter
 325                             let pair = bx.call(llfn, &[
 326                                 args[0].immediate(),
 327                                 args[1].immediate()
 328                             ], None);
 329                             let val = bx.extract_value(pair, 0);
 330                             let overflow = bx.zext(bx.extract_value(pair, 1), Type::bool(cx));
 331
 332                             let dest = result.project_field(bx, 0);
 333                             bx.store(val, dest.llval, dest.align);
 334                             let dest = result.project_field(bx, 1);
 335                             bx.store(overflow, dest.llval, dest.align);
 336
 337                             return;
 338                         },
 339                         "overflowing_add" => bx.add(args[0].immediate(), args[1].immediate()),
 340                         "overflowing_sub" => bx.sub(args[0].immediate(), args[1].immediate()),
 341                         "overflowing_mul" => bx.mul(args[0].immediate(), args[1].immediate()),
 342                         "unchecked_div" =>
 343                             if signed {
 344                                 bx.sdiv(args[0].immediate(), args[1].immediate())
 345                             } else {
 346                                 bx.udiv(args[0].immediate(), args[1].immediate())
 347                             },
 348                         "unchecked_rem" =>
 349                             if signed {
 350                                 bx.srem(args[0].immediate(), args[1].immediate())
 351                             } else {
 352                                 bx.urem(args[0].immediate(), args[1].immediate())
 353                             },
 354                         "unchecked_shl" => bx.shl(args[0].immediate(), args[1].immediate()),
 355                         "unchecked_shr" =>
 356                             if signed {
 357                                 bx.ashr(args[0].immediate(), args[1].immediate())
 358                             } else {
 359                                 bx.lshr(args[0].immediate(), args[1].immediate())
 360                             },
 361                         _ => bug!(),
 362                     },
 363                 None => {
 364                     span_invalid_monomorphization_error(
 365                         tcx.sess, span,
 366                         &format!("invalid monomorphization of `{}` intrinsic: \
 367                                   expected basic integer type, found `{}`", name, ty));
 368                     return;
 369                 }
 370             }
 371
 372         },
 373         "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => {
 374             let sty = &arg_tys[0].sty;
 375             match float_type_width(sty) {
 376                 Some(_width) =>
 377                     match name {
 378                         "fadd_fast" => bx.fadd_fast(args[0].immediate(), args[1].immediate()),
 379                         "fsub_fast" => bx.fsub_fast(args[0].immediate(), args[1].immediate()),
 380                         "fmul_fast" => bx.fmul_fast(args[0].immediate(), args[1].immediate()),
 381                         "fdiv_fast" => bx.fdiv_fast(args[0].immediate(), args[1].immediate()),
 382                         "frem_fast" => bx.frem_fast(args[0].immediate(), args[1].immediate()),
 383                         _ => bug!(),
 384                     },
 385                 None => {
 386                     span_invalid_monomorphization_error(
 387                         tcx.sess, span,
 388                         &format!("invalid monomorphization of `{}` intrinsic: \
 389                                   expected basic float type, found `{}`", name, sty));
 390                     return;
 391                 }
 392             }
 393
 394         },
 395
 396         "discriminant_value" => {
 397             args[0].deref(bx.cx).trans_get_discr(bx, ret_ty)
 398         }
 399
 400         "align_offset" => {
 401             // `ptr as usize`
 402             let ptr_val = bx.ptrtoint(args[0].immediate(), bx.cx.isize_ty);
 403             // `ptr_val % align`
 404             let align = args[1].immediate();
 405             let offset = bx.urem(ptr_val, align);
 406             let zero = C_null(bx.cx.isize_ty);
 407             // `offset == 0`
 408             let is_zero = bx.icmp(llvm::IntPredicate::IntEQ, offset, zero);
 409             // `if offset == 0 { 0 } else { align - offset }`
 410             bx.select(is_zero, zero, bx.sub(align, offset))
 411         }
 412         name if name.starts_with("simd_") => {
 413             match generic_simd_intrinsic(bx, name,
 414                                          callee_ty,
 415                                          args,
 416                                          ret_ty, llret_ty,
 417                                          span) {
 418                 Ok(llval) => llval,
 419                 Err(()) => return
 420             }
 421         }
 422         // This requires that atomic intrinsics follow a specific naming pattern:
 423         // "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
 424         name if name.starts_with("atomic_") => {
 425             use llvm::AtomicOrdering::*;
 426
 427             let split: Vec<&str> = name.split('_').collect();
 428
 429             let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
 430             let (order, failorder) = match split.len() {
 431                 2 => (SequentiallyConsistent, SequentiallyConsistent),
 432                 3 => match split[2] {
 433                     "unordered" => (Unordered, Unordered),
 434                     "relaxed" => (Monotonic, Monotonic),
 435                     "acq"     => (Acquire, Acquire),
 436                     "rel"     => (Release, Monotonic),
 437                     "acqrel"  => (AcquireRelease, Acquire),
 438                     "failrelaxed" if is_cxchg =>
 439                         (SequentiallyConsistent, Monotonic),
 440                     "failacq" if is_cxchg =>
 441                         (SequentiallyConsistent, Acquire),
 442                     _ => cx.sess().fatal("unknown ordering in atomic intrinsic")
 443                 },
 444                 4 => match (split[2], split[3]) {
 445                     ("acq", "failrelaxed") if is_cxchg =>
 446                         (Acquire, Monotonic),
 447                     ("acqrel", "failrelaxed") if is_cxchg =>
 448                         (AcquireRelease, Monotonic),
 449                     _ => cx.sess().fatal("unknown ordering in atomic intrinsic")
 450                 },
 451                 _ => cx.sess().fatal("Atomic intrinsic not in correct format"),
 452             };
 453
 454             let invalid_monomorphization = |ty| {
 455                 span_invalid_monomorphization_error(tcx.sess, span,
 456                     &format!("invalid monomorphization of `{}` intrinsic: \
 457                               expected basic integer type, found `{}`", name, ty));
 458             };
 459
 460             match split[1] {
 461                 "cxchg" | "cxchgweak" => {
 462                     let ty = substs.type_at(0);
 463                     if int_type_width_signed(ty, cx).is_some() {
 464                         let weak = if split[1] == "cxchgweak" { llvm::True } else { llvm::False };
 465                         let pair = bx.atomic_cmpxchg(
 466                             args[0].immediate(),
 467                             args[1].immediate(),
 468                             args[2].immediate(),
 469                             order,
 470                             failorder,
 471                             weak);
 472                         let val = bx.extract_value(pair, 0);
 473                         let success = bx.zext(bx.extract_value(pair, 1), Type::bool(bx.cx));
 474
 475                         let dest = result.project_field(bx, 0);
 476                         bx.store(val, dest.llval, dest.align);
 477                         let dest = result.project_field(bx, 1);
 478                         bx.store(success, dest.llval, dest.align);
 479                         return;
 480                     } else {
 481                         return invalid_monomorphization(ty);
 482                     }
 483                 }
 484
 485                 "load" => {
 486                     let ty = substs.type_at(0);
 487                     if int_type_width_signed(ty, cx).is_some() {
 488                         let align = cx.align_of(ty);
 489                         bx.atomic_load(args[0].immediate(), order, align)
 490                     } else {
 491                         return invalid_monomorphization(ty);
 492                     }
 493                 }
 494
 495                 "store" => {
 496                     let ty = substs.type_at(0);
 497                     if int_type_width_signed(ty, cx).is_some() {
 498                         let align = cx.align_of(ty);
 499                         bx.atomic_store(args[1].immediate(), args[0].immediate(), order, align);
 500                         return;
 501                     } else {
 502                         return invalid_monomorphization(ty);
 503                     }
 504                 }
 505
 506                 "fence" => {
 507                     bx.atomic_fence(order, llvm::SynchronizationScope::CrossThread);
 508                     return;
 509                 }
 510
 511                 "singlethreadfence" => {
 512                     bx.atomic_fence(order, llvm::SynchronizationScope::SingleThread);
 513                     return;
 514                 }
 515
 516                 // These are all AtomicRMW ops
 517                 op => {
 518                     let atom_op = match op {
 519                         "xchg"  => llvm::AtomicXchg,
 520                         "xadd"  => llvm::AtomicAdd,
 521                         "xsub"  => llvm::AtomicSub,
 522                         "and"   => llvm::AtomicAnd,
 523                         "nand"  => llvm::AtomicNand,
 524                         "or"    => llvm::AtomicOr,
 525                         "xor"   => llvm::AtomicXor,
 526                         "max"   => llvm::AtomicMax,
 527                         "min"   => llvm::AtomicMin,
 528                         "umax"  => llvm::AtomicUMax,
 529                         "umin"  => llvm::AtomicUMin,
 530                         _ => cx.sess().fatal("unknown atomic operation")
 531                     };
 532
 533                     let ty = substs.type_at(0);
 534                     if int_type_width_signed(ty, cx).is_some() {
 535                         bx.atomic_rmw(atom_op, args[0].immediate(), args[1].immediate(), order)
 536                     } else {
 537                         return invalid_monomorphization(ty);
 538                     }
 539                 }
 540             }
 541         }
 542
 543         "nontemporal_store" => {
 544             let tp_ty = substs.type_at(0);
 545             let dst = args[0].deref(bx.cx);
 546             let val = if let OperandValue::Ref(ptr, align) = args[1].val {
 547                 bx.load(ptr, align)
 548             } else {
 549                 from_immediate(bx, args[1].immediate())
 550             };
 551             let ptr = bx.pointercast(dst.llval, val_ty(val).ptr_to());
 552             let store = bx.nontemporal_store(val, ptr);
 553             unsafe {
 554                 llvm::LLVMSetAlignment(store, cx.align_of(tp_ty).abi() as u32);
 555             }
 556             return
 557         }
 558
 559         _ => {
 560             let intr = match Intrinsic::find(&name) {
 561                 Some(intr) => intr,
 562                 None => bug!("unknown intrinsic '{}'", name),
 563             };
 564             fn one<T>(x: Vec<T>) -> T {
 565                 assert_eq!(x.len(), 1);
 566                 x.into_iter().next().unwrap()
 567             }
 568             fn ty_to_type(cx: &CodegenCx, t: &intrinsics::Type) -> Vec<Type> {
 569                 use intrinsics::Type::*;
 570                 match *t {
 571                     Void => vec![Type::void(cx)],
 572                     Integer(_signed, _width, llvm_width) => {
 573                         vec![Type::ix(cx, llvm_width as u64)]
 574                     }
 575                     Float(x) => {
 576                         match x {
 577                             32 => vec![Type::f32(cx)],
 578                             64 => vec![Type::f64(cx)],
 579                             _ => bug!()
 580                         }
 581                     }
 582                     Pointer(ref t, ref llvm_elem, _const) => {
 583                         let t = llvm_elem.as_ref().unwrap_or(t);
 584                         let elem = one(ty_to_type(cx, t));
 585                         vec![elem.ptr_to()]
 586                     }
 587                     Vector(ref t, ref llvm_elem, length) => {
 588                         let t = llvm_elem.as_ref().unwrap_or(t);
 589                         let elem = one(ty_to_type(cx, t));
 590                         vec![Type::vector(&elem, length as u64)]
 591                     }
 592                     Aggregate(false, ref contents) => {
 593                         let elems = contents.iter()
 594                                             .map(|t| one(ty_to_type(cx, t)))
 595                                             .collect::<Vec<_>>();
 596                         vec![Type::struct_(cx, &elems, false)]
 597                     }
 598                     Aggregate(true, ref contents) => {
 599                         contents.iter()
 600                                 .flat_map(|t| ty_to_type(cx, t))
 601                                 .collect()
 602                     }
 603                 }
 604             }
 605
 606             // This allows an argument list like `foo, (bar, baz),
 607             // qux` to be converted into `foo, bar, baz, qux`, integer
 608             // arguments to be truncated as needed and pointers to be
 609             // cast.
 610             fn modify_as_needed<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
 611                                           t: &intrinsics::Type,
 612                                           arg: &OperandRef<'tcx>)
 613                                           -> Vec<ValueRef>
 614             {
 615                 match *t {
 616                     intrinsics::Type::Aggregate(true, ref contents) => {
 617                         // We found a tuple that needs squishing! So
 618                         // run over the tuple and load each field.
 619                         //
 620                         // This assumes the type is "simple", i.e. no
 621                         // destructors, and the contents are SIMD
 622                         // etc.
 623                         assert!(!bx.cx.type_needs_drop(arg.layout.ty));
 624                         let (ptr, align) = match arg.val {
 625                             OperandValue::Ref(ptr, align) => (ptr, align),
 626                             _ => bug!()
 627                         };
 628                         let arg = PlaceRef::new_sized(ptr, arg.layout, align);
 629                         (0..contents.len()).map(|i| {
 630                             arg.project_field(bx, i).load(bx).immediate()
 631                         }).collect()
 632                     }
 633                     intrinsics::Type::Pointer(_, Some(ref llvm_elem), _) => {
 634                         let llvm_elem = one(ty_to_type(bx.cx, llvm_elem));
 635                         vec![bx.pointercast(arg.immediate(), llvm_elem.ptr_to())]
 636                     }
 637                     intrinsics::Type::Vector(_, Some(ref llvm_elem), length) => {
 638                         let llvm_elem = one(ty_to_type(bx.cx, llvm_elem));
 639                         vec![bx.bitcast(arg.immediate(), Type::vector(&llvm_elem, length as u64))]
 640                     }
 641                     intrinsics::Type::Integer(_, width, llvm_width) if width != llvm_width => {
 642                         // the LLVM intrinsic uses a smaller integer
 643                         // size than the C intrinsic's signature, so
 644                         // we have to trim it down here.
 645                         vec![bx.trunc(arg.immediate(), Type::ix(bx.cx, llvm_width as u64))]
 646                     }
 647                     _ => vec![arg.immediate()],
 648                 }
 649             }
 650
 651
 652             let inputs = intr.inputs.iter()
 653                                     .flat_map(|t| ty_to_type(cx, t))
 654                                     .collect::<Vec<_>>();
 655
 656             let outputs = one(ty_to_type(cx, &intr.output));
 657
 658             let llargs: Vec<_> = intr.inputs.iter().zip(args).flat_map(|(t, arg)| {
 659                 modify_as_needed(bx, t, arg)
 660             }).collect();
 661             assert_eq!(inputs.len(), llargs.len());
 662
 663             let val = match intr.definition {
 664                 intrinsics::IntrinsicDef::Named(name) => {
 665                     let f = declare::declare_cfn(cx,
 666                                                  name,
 667                                                  Type::func(&inputs, &outputs));
 668                     bx.call(f, &llargs, None)
 669                 }
 670             };
 671
 672             match *intr.output {
 673                 intrinsics::Type::Aggregate(flatten, ref elems) => {
 674                     // the output is a tuple so we need to munge it properly
 675                     assert!(!flatten);
 676
 677                     for i in 0..elems.len() {
 678                         let dest = result.project_field(bx, i);
 679                         let val = bx.extract_value(val, i as u64);
 680                         bx.store(val, dest.llval, dest.align);
 681                     }
 682                     return;
 683                 }
 684                 _ => val,
 685             }
 686         }
 687     };
 688
 689     if !fn_ty.ret.is_ignore() {
 690         if let PassMode::Cast(ty) = fn_ty.ret.mode {
 691             let ptr = bx.pointercast(result.llval, ty.llvm_type(cx).ptr_to());
 692             bx.store(llval, ptr, result.align);
 693         } else {
 694             OperandRef::from_immediate_or_packed_pair(bx, llval, result.layout)
 695                 .val.store(bx, result);
 696         }
 697     }
 698 }
 699
 700 fn copy_intrinsic<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
 701                             allow_overlap: bool,
 702                             volatile: bool,
 703                             ty: Ty<'tcx>,
 704                             dst: ValueRef,
 705                             src: ValueRef,
 706                             count: ValueRef)
 707                             -> ValueRef {
 708     let cx = bx.cx;
 709     let (size, align) = cx.size_and_align_of(ty);
 710     let size = C_usize(cx, size.bytes());
 711     let align = C_i32(cx, align.abi() as i32);
 712
 713     let operation = if allow_overlap {
 714         "memmove"
 715     } else {
 716         "memcpy"
 717     };
 718
 719     let name = format!("llvm.{}.p0i8.p0i8.i{}", operation,
 720                        cx.data_layout().pointer_size.bits());
 721
 722     let dst_ptr = bx.pointercast(dst, Type::i8p(cx));
 723     let src_ptr = bx.pointercast(src, Type::i8p(cx));
 724     let llfn = cx.get_intrinsic(&name);
 725
 726     bx.call(llfn,
 727         &[dst_ptr,
 728         src_ptr,
 729         bx.mul(size, count),
 730         align,
 731         C_bool(cx, volatile)],
 732         None)
 733 }
 734
 735 fn memset_intrinsic<'a, 'tcx>(
 736     bx: &Builder<'a, 'tcx>,
 737     volatile: bool,
 738     ty: Ty<'tcx>,
 739     dst: ValueRef,
 740     val: ValueRef,
 741     count: ValueRef
 742 ) -> ValueRef {
 743     let cx = bx.cx;
 744     let (size, align) = cx.size_and_align_of(ty);
 745     let size = C_usize(cx, size.bytes());
 746     let align = C_i32(cx, align.abi() as i32);
 747     let dst = bx.pointercast(dst, Type::i8p(cx));
 748     call_memset(bx, dst, val, bx.mul(size, count), align, volatile)
 749 }
 750
 751 fn try_intrinsic<'a, 'tcx>(
 752     bx: &Builder<'a, 'tcx>,
 753     cx: &CodegenCx,
 754     func: ValueRef,
 755     data: ValueRef,
 756     local_ptr: ValueRef,
 757     dest: ValueRef,
 758 ) {
 759     if bx.sess().no_landing_pads() {
 760         bx.call(func, &[data], None);
 761         let ptr_align = bx.tcx().data_layout.pointer_align;
 762         bx.store(C_null(Type::i8p(&bx.cx)), dest, ptr_align);
 763     } else if wants_msvc_seh(bx.sess()) {
 764         trans_msvc_try(bx, cx, func, data, local_ptr, dest);
 765     } else {
 766         trans_gnu_try(bx, cx, func, data, local_ptr, dest);
 767     }
 768 }
 769
 770 // MSVC's definition of the `rust_try` function.
 771 //
 772 // This implementation uses the new exception handling instructions in LLVM
 773 // which have support in LLVM for SEH on MSVC targets. Although these
 774 // instructions are meant to work for all targets, as of the time of this
 775 // writing, however, LLVM does not recommend the usage of these new instructions
 776 // as the old ones are still more optimized.
 777 fn trans_msvc_try<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
 778                             cx: &CodegenCx,
 779                             func: ValueRef,
 780                             data: ValueRef,
 781                             local_ptr: ValueRef,
 782                             dest: ValueRef) {
 783     let llfn = get_rust_try_fn(cx, &mut |bx| {
 784         let cx = bx.cx;
 785
 786         bx.set_personality_fn(bx.cx.eh_personality());
 787
 788         let normal = bx.build_sibling_block("normal");
 789         let catchswitch = bx.build_sibling_block("catchswitch");
 790         let catchpad = bx.build_sibling_block("catchpad");
 791         let caught = bx.build_sibling_block("caught");
 792
 793         let func = llvm::get_param(bx.llfn(), 0);
 794         let data = llvm::get_param(bx.llfn(), 1);
 795         let local_ptr = llvm::get_param(bx.llfn(), 2);
 796
 797         // We're generating an IR snippet that looks like:
 798         //
 799         //   declare i32 @rust_try(%func, %data, %ptr) {
 800         //      %slot = alloca i64*
 801         //      invoke %func(%data) to label %normal unwind label %catchswitch
 802         //
 803         //   normal:
 804         //      ret i32 0
 805         //
 806         //   catchswitch:
 807         //      %cs = catchswitch within none [%catchpad] unwind to caller
 808         //
 809         //   catchpad:
 810         //      %tok = catchpad within %cs [%type_descriptor, 0, %slot]
 811         //      %ptr[0] = %slot[0]
 812         //      %ptr[1] = %slot[1]
 813         //      catchret from %tok to label %caught
 814         //
 815         //   caught:
 816         //      ret i32 1
 817         //   }
 818         //
 819         // This structure follows the basic usage of throw/try/catch in LLVM.
 820         // For example, compile this C++ snippet to see what LLVM generates:
 821         //
 822         //      #include <stdint.h>
 823         //
 824         //      int bar(void (*foo)(void), uint64_t *ret) {
 825         //          try {
 826         //              foo();
 827         //              return 0;
 828         //          } catch(uint64_t a[2]) {
 829         //              ret[0] = a[0];
 830         //              ret[1] = a[1];
 831         //              return 1;
 832         //          }
 833         //      }
 834         //
 835         // More information can be found in libstd's seh.rs implementation.
 836         let i64p = Type::i64(cx).ptr_to();
 837         let ptr_align = bx.tcx().data_layout.pointer_align;
 838         let slot = bx.alloca(i64p, "slot", ptr_align);
 839         bx.invoke(func, &[data], normal.llbb(), catchswitch.llbb(),
 840             None);
 841
 842         normal.ret(C_i32(cx, 0));
 843
 844         let cs = catchswitch.catch_switch(None, None, 1);
 845         catchswitch.add_handler(cs, catchpad.llbb());
 846
 847         let tcx = cx.tcx;
 848         let tydesc = match tcx.lang_items().msvc_try_filter() {
 849             Some(did) => ::consts::get_static(cx, did),
 850             None => bug!("msvc_try_filter not defined"),
 851         };
 852         let tok = catchpad.catch_pad(cs, &[tydesc, C_i32(cx, 0), slot]);
 853         let addr = catchpad.load(slot, ptr_align);
 854
 855         let i64_align = bx.tcx().data_layout.i64_align;
 856         let arg1 = catchpad.load(addr, i64_align);
 857         let val1 = C_i32(cx, 1);
 858         let arg2 = catchpad.load(catchpad.inbounds_gep(addr, &[val1]), i64_align);
 859         let local_ptr = catchpad.bitcast(local_ptr, i64p);
 860         catchpad.store(arg1, local_ptr, i64_align);
 861         catchpad.store(arg2, catchpad.inbounds_gep(local_ptr, &[val1]), i64_align);
 862         catchpad.catch_ret(tok, caught.llbb());
 863
 864         caught.ret(C_i32(cx, 1));
 865     });
 866
 867     // Note that no invoke is used here because by definition this function
 868     // can't panic (that's what it's catching).
 869     let ret = bx.call(llfn, &[func, data, local_ptr], None);
 870     let i32_align = bx.tcx().data_layout.i32_align;
 871     bx.store(ret, dest, i32_align);
 872 }
 873
 874 // Definition of the standard "try" function for Rust using the GNU-like model
 875 // of exceptions (e.g. the normal semantics of LLVM's landingpad and invoke
 876 // instructions).
 877 //
 878 // This translation is a little surprising because we always call a shim
 879 // function instead of inlining the call to `invoke` manually here. This is done
 880 // because in LLVM we're only allowed to have one personality per function
 881 // definition. The call to the `try` intrinsic is being inlined into the
 882 // function calling it, and that function may already have other personality
 883 // functions in play. By calling a shim we're guaranteed that our shim will have
 884 // the right personality function.
 885 fn trans_gnu_try<'a, 'tcx>(bx: &Builder<'a, 'tcx>,
 886                            cx: &CodegenCx,
 887                            func: ValueRef,
 888                            data: ValueRef,
 889                            local_ptr: ValueRef,
 890                            dest: ValueRef) {
 891     let llfn = get_rust_try_fn(cx, &mut |bx| {
 892         let cx = bx.cx;
 893
 894         // Translates the shims described above:
 895         //
 896         //   bx:
 897         //      invoke %func(%args...) normal %normal unwind %catch
 898         //
 899         //   normal:
 900         //      ret 0
 901         //
 902         //   catch:
 903         //      (ptr, _) = landingpad
 904         //      store ptr, %local_ptr
 905         //      ret 1
 906         //
 907         // Note that the `local_ptr` data passed into the `try` intrinsic is
 908         // expected to be `*mut *mut u8` for this to actually work, but that's
 909         // managed by the standard library.
 910
 911         let then = bx.build_sibling_block("then");
 912         let catch = bx.build_sibling_block("catch");
 913
 914         let func = llvm::get_param(bx.llfn(), 0);
 915         let data = llvm::get_param(bx.llfn(), 1);
 916         let local_ptr = llvm::get_param(bx.llfn(), 2);
 917         bx.invoke(func, &[data], then.llbb(), catch.llbb(), None);
 918         then.ret(C_i32(cx, 0));
 919
 920         // Type indicator for the exception being thrown.
 921         //
 922         // The first value in this tuple is a pointer to the exception object
 923         // being thrown.  The second value is a "selector" indicating which of
 924         // the landing pad clauses the exception's type had been matched to.
 925         // rust_try ignores the selector.
 926         let lpad_ty = Type::struct_(cx, &[Type::i8p(cx), Type::i32(cx)],
 927                                     false);
 928         let vals = catch.landing_pad(lpad_ty, bx.cx.eh_personality(), 1);
 929         catch.add_clause(vals, C_null(Type::i8p(cx)));
 930         let ptr = catch.extract_value(vals, 0);
 931         let ptr_align = bx.tcx().data_layout.pointer_align;
 932         catch.store(ptr, catch.bitcast(local_ptr, Type::i8p(cx).ptr_to()), ptr_align);
 933         catch.ret(C_i32(cx, 1));
 934     });
 935
 936     // Note that no invoke is used here because by definition this function
 937     // can't panic (that's what it's catching).
 938     let ret = bx.call(llfn, &[func, data, local_ptr], None);
 939     let i32_align = bx.tcx().data_layout.i32_align;
 940     bx.store(ret, dest, i32_align);
 941 }
 942
 943 // Helper function to give a Block to a closure to translate a shim function.
 944 // This is currently primarily used for the `try` intrinsic functions above.
 945 fn gen_fn<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
 946                     name: &str,
 947                     inputs: Vec<Ty<'tcx>>,
 948                     output: Ty<'tcx>,
 949                     trans: &mut for<'b> FnMut(Builder<'b, 'tcx>))
 950                     -> ValueRef {
 951     let rust_fn_ty = cx.tcx.mk_fn_ptr(ty::Binder(cx.tcx.mk_fn_sig(
 952         inputs.into_iter(),
 953         output,
 954         false,
 955         hir::Unsafety::Unsafe,
 956         Abi::Rust
 957     )));
 958     let llfn = declare::define_internal_fn(cx, name, rust_fn_ty);
 959     let bx = Builder::new_block(cx, llfn, "entry-block");
 960     trans(bx);
 961     llfn
 962 }
 963
 964 // Helper function used to get a handle to the `__rust_try` function used to
 965 // catch exceptions.
 966 //
 967 // This function is only generated once and is then cached.
 968 fn get_rust_try_fn<'a, 'tcx>(cx: &CodegenCx<'a, 'tcx>,
 969                              trans: &mut for<'b> FnMut(Builder<'b, 'tcx>))
 970                              -> ValueRef {
 971     if let Some(llfn) = cx.rust_try_fn.get() {
 972         return llfn;
 973     }
 974
 975     // Define the type up front for the signature of the rust_try function.
 976     let tcx = cx.tcx;
 977     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
 978     let fn_ty = tcx.mk_fn_ptr(ty::Binder(tcx.mk_fn_sig(
 979         iter::once(i8p),
 980         tcx.mk_nil(),
 981         false,
 982         hir::Unsafety::Unsafe,
 983         Abi::Rust
 984     )));
 985     let output = tcx.types.i32;
 986     let rust_try = gen_fn(cx, "__rust_try", vec![fn_ty, i8p, i8p], output, trans);
 987     cx.rust_try_fn.set(Some(rust_try));
 988     return rust_try
 989 }
 990
 991 fn span_invalid_monomorphization_error(a: &Session, b: Span, c: &str) {
 992     span_err!(a, b, E0511, "{}", c);
 993 }
 994
 995 fn generic_simd_intrinsic<'a, 'tcx>(
 996     bx: &Builder<'a, 'tcx>,
 997     name: &str,
 998     callee_ty: Ty<'tcx>,
 999     args: &[OperandRef<'tcx>],
1000     ret_ty: Ty<'tcx>,
1001     llret_ty: Type,
1002     span: Span
1003 ) -> Result<ValueRef, ()> {
1004     // macros for error handling:
1005     macro_rules! emit_error {
1006         ($msg: tt) => {
1007             emit_error!($msg, )
1008         };
1009         ($msg: tt, $($fmt: tt)*) => {
1010             span_invalid_monomorphization_error(
1011                 bx.sess(), span,
1012                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ",
1013                                  $msg),
1014                          name, $($fmt)*));
1015         }
1016     }
1017     macro_rules! require {
1018         ($cond: expr, $($fmt: tt)*) => {
1019             if !$cond {
1020                 emit_error!($($fmt)*);
1021                 return Err(());
1022             }
1023         }
1024     }
1025     macro_rules! require_simd {
1026         ($ty: expr, $position: expr) => {
1027             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
1028         }
1029     }
1030
1031
1032
1033     let tcx = bx.tcx();
1034     let sig = tcx.erase_late_bound_regions_and_normalize(&callee_ty.fn_sig(tcx));
1035     let arg_tys = sig.inputs();
1036
1037     // every intrinsic takes a SIMD vector as its first argument
1038     require_simd!(arg_tys[0], "input");
1039     let in_ty = arg_tys[0];
1040     let in_elem = arg_tys[0].simd_type(tcx);
1041     let in_len = arg_tys[0].simd_size(tcx);
1042
1043     let comparison = match name {
1044         "simd_eq" => Some(hir::BiEq),
1045         "simd_ne" => Some(hir::BiNe),
1046         "simd_lt" => Some(hir::BiLt),
1047         "simd_le" => Some(hir::BiLe),
1048         "simd_gt" => Some(hir::BiGt),
1049         "simd_ge" => Some(hir::BiGe),
1050         _ => None
1051     };
1052
1053     if let Some(cmp_op) = comparison {
1054         require_simd!(ret_ty, "return");
1055
1056         let out_len = ret_ty.simd_size(tcx);
1057         require!(in_len == out_len,
1058                  "expected return type with length {} (same as input type `{}`), \
1059                   found `{}` with length {}",
1060                  in_len, in_ty,
1061                  ret_ty, out_len);
1062         require!(llret_ty.element_type().kind() == llvm::Integer,
1063                  "expected return type with integer elements, found `{}` with non-integer `{}`",
1064                  ret_ty,
1065                  ret_ty.simd_type(tcx));
1066
1067         return Ok(compare_simd_types(bx,
1068                                      args[0].immediate(),
1069                                      args[1].immediate(),
1070                                      in_elem,
1071                                      llret_ty,
1072                                      cmp_op))
1073     }
1074
1075     if name.starts_with("simd_shuffle") {
1076         let n: usize = match name["simd_shuffle".len()..].parse() {
1077             Ok(n) => n,
1078             Err(_) => span_bug!(span,
1079                                 "bad `simd_shuffle` instruction only caught in trans?")
1080         };
1081
1082         require_simd!(ret_ty, "return");
1083
1084         let out_len = ret_ty.simd_size(tcx);
1085         require!(out_len == n,
1086                  "expected return type of length {}, found `{}` with length {}",
1087                  n, ret_ty, out_len);
1088         require!(in_elem == ret_ty.simd_type(tcx),
1089                  "expected return element type `{}` (element of input `{}`), \
1090                   found `{}` with element type `{}`",
1091                  in_elem, in_ty,
1092                  ret_ty, ret_ty.simd_type(tcx));
1093
1094         let total_len = in_len as u128 * 2;
1095
1096         let vector = args[2].immediate();
1097
1098         let indices: Option<Vec<_>> = (0..n)
1099             .map(|i| {
1100                 let arg_idx = i;
1101                 let val = const_get_elt(vector, i as u64);
1102                 match const_to_opt_u128(val, true) {
1103                     None => {
1104                         emit_error!("shuffle index #{} is not a constant", arg_idx);
1105                         None
1106                     }
1107                     Some(idx) if idx >= total_len => {
1108                         emit_error!("shuffle index #{} is out of bounds (limit {})",
1109                                     arg_idx, total_len);
1110                         None
1111                     }
1112                     Some(idx) => Some(C_i32(bx.cx, idx as i32)),
1113                 }
1114             })
1115             .collect();
1116         let indices = match indices {
1117             Some(i) => i,
1118             None => return Ok(C_null(llret_ty))
1119         };
1120
1121         return Ok(bx.shuffle_vector(args[0].immediate(),
1122                                      args[1].immediate(),
1123                                      C_vector(&indices)))
1124     }
1125
1126     if name == "simd_insert" {
1127         require!(in_elem == arg_tys[2],
1128                  "expected inserted type `{}` (element of input `{}`), found `{}`",
1129                  in_elem, in_ty, arg_tys[2]);
1130         return Ok(bx.insert_element(args[0].immediate(),
1131                                      args[2].immediate(),
1132                                      args[1].immediate()))
1133     }
1134     if name == "simd_extract" {
1135         require!(ret_ty == in_elem,
1136                  "expected return type `{}` (element of input `{}`), found `{}`",
1137                  in_elem, in_ty, ret_ty);
1138         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()))
1139     }
1140
1141     if name == "simd_cast" {
1142         require_simd!(ret_ty, "return");
1143         let out_len = ret_ty.simd_size(tcx);
1144         require!(in_len == out_len,
1145                  "expected return type with length {} (same as input type `{}`), \
1146                   found `{}` with length {}",
1147                  in_len, in_ty,
1148                  ret_ty, out_len);
1149         // casting cares about nominal type, not just structural type
1150         let out_elem = ret_ty.simd_type(tcx);
1151
1152         if in_elem == out_elem { return Ok(args[0].immediate()); }
1153
1154         enum Style { Float, Int(/* is signed? */ bool), Unsupported }
1155
1156         let (in_style, in_width) = match in_elem.sty {
1157             // vectors of pointer-sized integers should've been
1158             // disallowed before here, so this unwrap is safe.
1159             ty::TyInt(i) => (Style::Int(true), i.bit_width().unwrap()),
1160             ty::TyUint(u) => (Style::Int(false), u.bit_width().unwrap()),
1161             ty::TyFloat(f) => (Style::Float, f.bit_width()),
1162             _ => (Style::Unsupported, 0)
1163         };
1164         let (out_style, out_width) = match out_elem.sty {
1165             ty::TyInt(i) => (Style::Int(true), i.bit_width().unwrap()),
1166             ty::TyUint(u) => (Style::Int(false), u.bit_width().unwrap()),
1167             ty::TyFloat(f) => (Style::Float, f.bit_width()),
1168             _ => (Style::Unsupported, 0)
1169         };
1170
1171         match (in_style, out_style) {
1172             (Style::Int(in_is_signed), Style::Int(_)) => {
1173                 return Ok(match in_width.cmp(&out_width) {
1174                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
1175                     Ordering::Equal => args[0].immediate(),
1176                     Ordering::Less => if in_is_signed {
1177                         bx.sext(args[0].immediate(), llret_ty)
1178                     } else {
1179                         bx.zext(args[0].immediate(), llret_ty)
1180                     }
1181                 })
1182             }
1183             (Style::Int(in_is_signed), Style::Float) => {
1184                 return Ok(if in_is_signed {
1185                     bx.sitofp(args[0].immediate(), llret_ty)
1186                 } else {
1187                     bx.uitofp(args[0].immediate(), llret_ty)
1188                 })
1189             }
1190             (Style::Float, Style::Int(out_is_signed)) => {
1191                 return Ok(if out_is_signed {
1192                     bx.fptosi(args[0].immediate(), llret_ty)
1193                 } else {
1194                     bx.fptoui(args[0].immediate(), llret_ty)
1195                 })
1196             }
1197             (Style::Float, Style::Float) => {
1198                 return Ok(match in_width.cmp(&out_width) {
1199                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
1200                     Ordering::Equal => args[0].immediate(),
1201                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty)
1202                 })
1203             }
1204             _ => {/* Unsupported. Fallthrough. */}
1205         }
1206         require!(false,
1207                  "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
1208                  in_ty, in_elem,
1209                  ret_ty, out_elem);
1210     }
1211     macro_rules! arith {
1212         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1213             $(if name == stringify!($name) {
1214                 match in_elem.sty {
1215                     $($(ty::$p(_))|* => {
1216                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
1217                     })*
1218                     _ => {},
1219                 }
1220                 require!(false,
1221                             "unsupported operation on `{}` with element `{}`",
1222                             in_ty,
1223                             in_elem)
1224             })*
1225         }
1226     }
1227     arith! {
1228         simd_add: TyUint, TyInt => add, TyFloat => fadd;
1229         simd_sub: TyUint, TyInt => sub, TyFloat => fsub;
1230         simd_mul: TyUint, TyInt => mul, TyFloat => fmul;
1231         simd_div: TyUint => udiv, TyInt => sdiv, TyFloat => fdiv;
1232         simd_rem: TyUint => urem, TyInt => srem, TyFloat => frem;
1233         simd_shl: TyUint, TyInt => shl;
1234         simd_shr: TyUint => lshr, TyInt => ashr;
1235         simd_and: TyUint, TyInt => and;
1236         simd_or: TyUint, TyInt => or;
1237         simd_xor: TyUint, TyInt => xor;
1238     }
1239     span_bug!(span, "unknown SIMD intrinsic");
1240 }
1241
1242 // Returns the width of an int Ty, and if it's signed or not
1243 // Returns None if the type is not an integer
1244 // FIXME: there’s multiple of this functions, investigate using some of the already existing
1245 // stuffs.
1246 fn int_type_width_signed(ty: Ty, cx: &CodegenCx) -> Option<(u64, bool)> {
1247     match ty.sty {
1248         ty::TyInt(t) => Some((match t {
1249             ast::IntTy::Isize => {
1250                 match &cx.tcx.sess.target.target.target_pointer_width[..] {
1251                     "16" => 16,
1252                     "32" => 32,
1253                     "64" => 64,
1254                     tws => bug!("Unsupported target word size for isize: {}", tws),
1255                 }
1256             },
1257             ast::IntTy::I8 => 8,
1258             ast::IntTy::I16 => 16,
1259             ast::IntTy::I32 => 32,
1260             ast::IntTy::I64 => 64,
1261             ast::IntTy::I128 => 128,
1262         }, true)),
1263         ty::TyUint(t) => Some((match t {
1264             ast::UintTy::Usize => {
1265                 match &cx.tcx.sess.target.target.target_pointer_width[..] {
1266                     "16" => 16,
1267                     "32" => 32,
1268                     "64" => 64,
1269                     tws => bug!("Unsupported target word size for usize: {}", tws),
1270                 }
1271             },
1272             ast::UintTy::U8 => 8,
1273             ast::UintTy::U16 => 16,
1274             ast::UintTy::U32 => 32,
1275             ast::UintTy::U64 => 64,
1276             ast::UintTy::U128 => 128,
1277         }, false)),
1278         _ => None,
1279     }
1280 }
1281
1282 // Returns the width of a float TypeVariant
1283 // Returns None if the type is not a float
1284 fn float_type_width<'tcx>(sty: &ty::TypeVariants<'tcx>)
1285         -> Option<u64> {
1286     use rustc::ty::TyFloat;
1287     match *sty {
1288         TyFloat(t) => Some(match t {
1289             ast::FloatTy::F32 => 32,
1290             ast::FloatTy::F64 => 64,
1291         }),
1292         _ => None,
1293     }
1294 }