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