src/librustc_codegen_llvm/intrinsic.rs

   1 use crate::abi::{Abi, FnAbi, LlvmType, PassMode};
   2 use crate::builder::Builder;
   3 use crate::context::CodegenCx;
   4 use crate::llvm;
   5 use crate::type_::Type;
   6 use crate::type_of::LayoutLlvmExt;
   7 use crate::va_arg::emit_va_arg;
   8 use crate::value::Value;
   9
  10 use log::debug;
  11
  12 use rustc_ast::ast;
  13 use rustc_codegen_ssa::base::{compare_simd_types, to_immediate, wants_msvc_seh};
  14 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
  15 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
  16 use rustc_codegen_ssa::coverageinfo;
  17 use rustc_codegen_ssa::glue;
  18 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
  19 use rustc_codegen_ssa::mir::place::PlaceRef;
  20 use rustc_codegen_ssa::traits::*;
  21 use rustc_codegen_ssa::MemFlags;
  22 use rustc_hir as hir;
  23 use rustc_middle::mir::coverage;
  24 use rustc_middle::mir::Operand;
  25 use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
  26 use rustc_middle::ty::{self, Ty};
  27 use rustc_middle::{bug, span_bug};
  28 use rustc_span::{sym, symbol::kw, Span, Symbol};
  29 use rustc_target::abi::{self, HasDataLayout, LayoutOf, Primitive};
  30 use rustc_target::spec::PanicStrategy;
  31
  32 use std::cmp::Ordering;
  33 use std::iter;
  34
  35 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: Symbol) -> Option<&'ll Value> {
  36     let llvm_name = match name {
  37         sym::sqrtf32 => "llvm.sqrt.f32",
  38         sym::sqrtf64 => "llvm.sqrt.f64",
  39         sym::powif32 => "llvm.powi.f32",
  40         sym::powif64 => "llvm.powi.f64",
  41         sym::sinf32 => "llvm.sin.f32",
  42         sym::sinf64 => "llvm.sin.f64",
  43         sym::cosf32 => "llvm.cos.f32",
  44         sym::cosf64 => "llvm.cos.f64",
  45         sym::powf32 => "llvm.pow.f32",
  46         sym::powf64 => "llvm.pow.f64",
  47         sym::expf32 => "llvm.exp.f32",
  48         sym::expf64 => "llvm.exp.f64",
  49         sym::exp2f32 => "llvm.exp2.f32",
  50         sym::exp2f64 => "llvm.exp2.f64",
  51         sym::logf32 => "llvm.log.f32",
  52         sym::logf64 => "llvm.log.f64",
  53         sym::log10f32 => "llvm.log10.f32",
  54         sym::log10f64 => "llvm.log10.f64",
  55         sym::log2f32 => "llvm.log2.f32",
  56         sym::log2f64 => "llvm.log2.f64",
  57         sym::fmaf32 => "llvm.fma.f32",
  58         sym::fmaf64 => "llvm.fma.f64",
  59         sym::fabsf32 => "llvm.fabs.f32",
  60         sym::fabsf64 => "llvm.fabs.f64",
  61         sym::minnumf32 => "llvm.minnum.f32",
  62         sym::minnumf64 => "llvm.minnum.f64",
  63         sym::maxnumf32 => "llvm.maxnum.f32",
  64         sym::maxnumf64 => "llvm.maxnum.f64",
  65         sym::copysignf32 => "llvm.copysign.f32",
  66         sym::copysignf64 => "llvm.copysign.f64",
  67         sym::floorf32 => "llvm.floor.f32",
  68         sym::floorf64 => "llvm.floor.f64",
  69         sym::ceilf32 => "llvm.ceil.f32",
  70         sym::ceilf64 => "llvm.ceil.f64",
  71         sym::truncf32 => "llvm.trunc.f32",
  72         sym::truncf64 => "llvm.trunc.f64",
  73         sym::rintf32 => "llvm.rint.f32",
  74         sym::rintf64 => "llvm.rint.f64",
  75         sym::nearbyintf32 => "llvm.nearbyint.f32",
  76         sym::nearbyintf64 => "llvm.nearbyint.f64",
  77         sym::roundf32 => "llvm.round.f32",
  78         sym::roundf64 => "llvm.round.f64",
  79         sym::assume => "llvm.assume",
  80         sym::abort => "llvm.trap",
  81         _ => return None,
  82     };
  83     Some(cx.get_intrinsic(&llvm_name))
  84 }
  85
  86 impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
  87     fn is_codegen_intrinsic(
  88         &mut self,
  89         intrinsic: Symbol,
  90         args: &Vec<Operand<'tcx>>,
  91         caller_instance: ty::Instance<'tcx>,
  92     ) -> bool {
  93         let mut is_codegen_intrinsic = true;
  94         // Set `is_codegen_intrinsic` to `false` to bypass `codegen_intrinsic_call()`.
  95
  96         // FIXME(richkadel): Make sure to add coverage analysis tests on a crate with
  97         // external crate dependencies, where:
  98         //   1. Both binary and dependent crates are compiled with `-Zinstrument-coverage`
  99         //   2. Only binary is compiled with `-Zinstrument-coverage`
 100         //   3. Only dependent crates are compiled with `-Zinstrument-coverage`
 101         match intrinsic {
 102             sym::count_code_region => {
 103                 use coverage::count_code_region_args::*;
 104                 self.add_counter_region(
 105                     caller_instance,
 106                     op_to_u64(&args[FUNCTION_SOURCE_HASH]),
 107                     op_to_u32(&args[COUNTER_ID]),
 108                     coverageinfo::Region::new(
 109                         op_to_str_slice(&args[FILE_NAME]),
 110                         op_to_u32(&args[START_LINE]),
 111                         op_to_u32(&args[START_COL]),
 112                         op_to_u32(&args[END_LINE]),
 113                         op_to_u32(&args[END_COL]),
 114                     ),
 115                 );
 116             }
 117             sym::coverage_counter_add | sym::coverage_counter_subtract => {
 118                 is_codegen_intrinsic = false;
 119                 use coverage::coverage_counter_expression_args::*;
 120                 self.add_counter_expression_region(
 121                     caller_instance,
 122                     op_to_u32(&args[EXPRESSION_ID]),
 123                     op_to_u32(&args[LEFT_ID]),
 124                     if intrinsic == sym::coverage_counter_add {
 125                         coverageinfo::ExprKind::Add
 126                     } else {
 127                         coverageinfo::ExprKind::Subtract
 128                     },
 129                     op_to_u32(&args[RIGHT_ID]),
 130                     coverageinfo::Region::new(
 131                         op_to_str_slice(&args[FILE_NAME]),
 132                         op_to_u32(&args[START_LINE]),
 133                         op_to_u32(&args[START_COL]),
 134                         op_to_u32(&args[END_LINE]),
 135                         op_to_u32(&args[END_COL]),
 136                     ),
 137                 );
 138             }
 139             sym::coverage_unreachable => {
 140                 is_codegen_intrinsic = false;
 141                 use coverage::coverage_unreachable_args::*;
 142                 self.add_unreachable_region(
 143                     caller_instance,
 144                     coverageinfo::Region::new(
 145                         op_to_str_slice(&args[FILE_NAME]),
 146                         op_to_u32(&args[START_LINE]),
 147                         op_to_u32(&args[START_COL]),
 148                         op_to_u32(&args[END_LINE]),
 149                         op_to_u32(&args[END_COL]),
 150                     ),
 151                 );
 152             }
 153             _ => {}
 154         }
 155         is_codegen_intrinsic
 156     }
 157
 158     fn codegen_intrinsic_call(
 159         &mut self,
 160         instance: ty::Instance<'tcx>,
 161         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
 162         args: &[OperandRef<'tcx, &'ll Value>],
 163         llresult: &'ll Value,
 164         span: Span,
 165         caller_instance: ty::Instance<'tcx>,
 166     ) {
 167         let tcx = self.tcx;
 168         let callee_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
 169
 170         let (def_id, substs) = match callee_ty.kind {
 171             ty::FnDef(def_id, substs) => (def_id, substs),
 172             _ => bug!("expected fn item type, found {}", callee_ty),
 173         };
 174
 175         let sig = callee_ty.fn_sig(tcx);
 176         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
 177         let arg_tys = sig.inputs();
 178         let ret_ty = sig.output();
 179         let name = tcx.item_name(def_id);
 180         let name_str = &*name.as_str();
 181
 182         let llret_ty = self.layout_of(ret_ty).llvm_type(self);
 183         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 184
 185         let simple = get_simple_intrinsic(self, name);
 186         let llval = match name {
 187             _ if simple.is_some() => self.call(
 188                 simple.unwrap(),
 189                 &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 190                 None,
 191             ),
 192             sym::unreachable => {
 193                 return;
 194             }
 195             sym::likely => {
 196                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 197                 self.call(expect, &[args[0].immediate(), self.const_bool(true)], None)
 198             }
 199             sym::unlikely => {
 200                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 201                 self.call(expect, &[args[0].immediate(), self.const_bool(false)], None)
 202             }
 203             kw::Try => {
 204                 try_intrinsic(
 205                     self,
 206                     args[0].immediate(),
 207                     args[1].immediate(),
 208                     args[2].immediate(),
 209                     llresult,
 210                 );
 211                 return;
 212             }
 213             sym::breakpoint => {
 214                 let llfn = self.get_intrinsic(&("llvm.debugtrap"));
 215                 self.call(llfn, &[], None)
 216             }
 217             sym::count_code_region => {
 218                 let coverageinfo = tcx.coverageinfo(caller_instance.def_id());
 219                 let mangled_fn = tcx.symbol_name(caller_instance);
 220                 let (mangled_fn_name, _len_val) = self.const_str(Symbol::intern(mangled_fn.name));
 221                 let num_counters = self.const_u32(coverageinfo.num_counters);
 222                 use coverage::count_code_region_args::*;
 223                 let hash = args[FUNCTION_SOURCE_HASH].immediate();
 224                 let index = args[COUNTER_ID].immediate();
 225                 debug!(
 226                     "translating Rust intrinsic `count_code_region()` to LLVM intrinsic: \
 227                     instrprof.increment(fn_name={}, hash={:?}, num_counters={:?}, index={:?})",
 228                     mangled_fn.name, hash, num_counters, index,
 229                 );
 230                 self.instrprof_increment(mangled_fn_name, hash, num_counters, index)
 231             }
 232             sym::va_start => self.va_start(args[0].immediate()),
 233             sym::va_end => self.va_end(args[0].immediate()),
 234             sym::va_copy => {
 235                 let intrinsic = self.cx().get_intrinsic(&("llvm.va_copy"));
 236                 self.call(intrinsic, &[args[0].immediate(), args[1].immediate()], None)
 237             }
 238             sym::va_arg => {
 239                 match fn_abi.ret.layout.abi {
 240                     abi::Abi::Scalar(ref scalar) => {
 241                         match scalar.value {
 242                             Primitive::Int(..) => {
 243                                 if self.cx().size_of(ret_ty).bytes() < 4 {
 244                                     // `va_arg` should not be called on a integer type
 245                                     // less than 4 bytes in length. If it is, promote
 246                                     // the integer to a `i32` and truncate the result
 247                                     // back to the smaller type.
 248                                     let promoted_result = emit_va_arg(self, args[0], tcx.types.i32);
 249                                     self.trunc(promoted_result, llret_ty)
 250                                 } else {
 251                                     emit_va_arg(self, args[0], ret_ty)
 252                                 }
 253                             }
 254                             Primitive::F64 | Primitive::Pointer => {
 255                                 emit_va_arg(self, args[0], ret_ty)
 256                             }
 257                             // `va_arg` should never be used with the return type f32.
 258                             Primitive::F32 => bug!("the va_arg intrinsic does not work with `f32`"),
 259                         }
 260                     }
 261                     _ => bug!("the va_arg intrinsic does not work with non-scalar types"),
 262                 }
 263             }
 264             sym::size_of_val => {
 265                 let tp_ty = substs.type_at(0);
 266                 if let OperandValue::Pair(_, meta) = args[0].val {
 267                     let (llsize, _) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 268                     llsize
 269                 } else {
 270                     self.const_usize(self.size_of(tp_ty).bytes())
 271                 }
 272             }
 273             sym::min_align_of_val => {
 274                 let tp_ty = substs.type_at(0);
 275                 if let OperandValue::Pair(_, meta) = args[0].val {
 276                     let (_, llalign) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 277                     llalign
 278                 } else {
 279                     self.const_usize(self.align_of(tp_ty).bytes())
 280                 }
 281             }
 282             sym::size_of
 283             | sym::pref_align_of
 284             | sym::min_align_of
 285             | sym::needs_drop
 286             | sym::type_id
 287             | sym::type_name
 288             | sym::variant_count => {
 289                 let value = self
 290                     .tcx
 291                     .const_eval_instance(ty::ParamEnv::reveal_all(), instance, None)
 292                     .unwrap();
 293                 OperandRef::from_const(self, value, ret_ty).immediate_or_packed_pair(self)
 294             }
 295             // Effectively no-op
 296             sym::forget => {
 297                 return;
 298             }
 299             sym::offset => {
 300                 let ptr = args[0].immediate();
 301                 let offset = args[1].immediate();
 302                 self.inbounds_gep(ptr, &[offset])
 303             }
 304             sym::arith_offset => {
 305                 let ptr = args[0].immediate();
 306                 let offset = args[1].immediate();
 307                 self.gep(ptr, &[offset])
 308             }
 309
 310             sym::copy_nonoverlapping => {
 311                 copy_intrinsic(
 312                     self,
 313                     false,
 314                     false,
 315                     substs.type_at(0),
 316                     args[1].immediate(),
 317                     args[0].immediate(),
 318                     args[2].immediate(),
 319                 );
 320                 return;
 321             }
 322             sym::copy => {
 323                 copy_intrinsic(
 324                     self,
 325                     true,
 326                     false,
 327                     substs.type_at(0),
 328                     args[1].immediate(),
 329                     args[0].immediate(),
 330                     args[2].immediate(),
 331                 );
 332                 return;
 333             }
 334             sym::write_bytes => {
 335                 memset_intrinsic(
 336                     self,
 337                     false,
 338                     substs.type_at(0),
 339                     args[0].immediate(),
 340                     args[1].immediate(),
 341                     args[2].immediate(),
 342                 );
 343                 return;
 344             }
 345
 346             sym::volatile_copy_nonoverlapping_memory => {
 347                 copy_intrinsic(
 348                     self,
 349                     false,
 350                     true,
 351                     substs.type_at(0),
 352                     args[0].immediate(),
 353                     args[1].immediate(),
 354                     args[2].immediate(),
 355                 );
 356                 return;
 357             }
 358             sym::volatile_copy_memory => {
 359                 copy_intrinsic(
 360                     self,
 361                     true,
 362                     true,
 363                     substs.type_at(0),
 364                     args[0].immediate(),
 365                     args[1].immediate(),
 366                     args[2].immediate(),
 367                 );
 368                 return;
 369             }
 370             sym::volatile_set_memory => {
 371                 memset_intrinsic(
 372                     self,
 373                     true,
 374                     substs.type_at(0),
 375                     args[0].immediate(),
 376                     args[1].immediate(),
 377                     args[2].immediate(),
 378                 );
 379                 return;
 380             }
 381             sym::volatile_load | sym::unaligned_volatile_load => {
 382                 let tp_ty = substs.type_at(0);
 383                 let mut ptr = args[0].immediate();
 384                 if let PassMode::Cast(ty) = fn_abi.ret.mode {
 385                     ptr = self.pointercast(ptr, self.type_ptr_to(ty.llvm_type(self)));
 386                 }
 387                 let load = self.volatile_load(ptr);
 388                 let align = if name == sym::unaligned_volatile_load {
 389                     1
 390                 } else {
 391                     self.align_of(tp_ty).bytes() as u32
 392                 };
 393                 unsafe {
 394                     llvm::LLVMSetAlignment(load, align);
 395                 }
 396                 to_immediate(self, load, self.layout_of(tp_ty))
 397             }
 398             sym::volatile_store => {
 399                 let dst = args[0].deref(self.cx());
 400                 args[1].val.volatile_store(self, dst);
 401                 return;
 402             }
 403             sym::unaligned_volatile_store => {
 404                 let dst = args[0].deref(self.cx());
 405                 args[1].val.unaligned_volatile_store(self, dst);
 406                 return;
 407             }
 408             sym::prefetch_read_data
 409             | sym::prefetch_write_data
 410             | sym::prefetch_read_instruction
 411             | sym::prefetch_write_instruction => {
 412                 let expect = self.get_intrinsic(&("llvm.prefetch"));
 413                 let (rw, cache_type) = match name {
 414                     sym::prefetch_read_data => (0, 1),
 415                     sym::prefetch_write_data => (1, 1),
 416                     sym::prefetch_read_instruction => (0, 0),
 417                     sym::prefetch_write_instruction => (1, 0),
 418                     _ => bug!(),
 419                 };
 420                 self.call(
 421                     expect,
 422                     &[
 423                         args[0].immediate(),
 424                         self.const_i32(rw),
 425                         args[1].immediate(),
 426                         self.const_i32(cache_type),
 427                     ],
 428                     None,
 429                 )
 430             }
 431             sym::ctlz
 432             | sym::ctlz_nonzero
 433             | sym::cttz
 434             | sym::cttz_nonzero
 435             | sym::ctpop
 436             | sym::bswap
 437             | sym::bitreverse
 438             | sym::add_with_overflow
 439             | sym::sub_with_overflow
 440             | sym::mul_with_overflow
 441             | sym::wrapping_add
 442             | sym::wrapping_sub
 443             | sym::wrapping_mul
 444             | sym::unchecked_div
 445             | sym::unchecked_rem
 446             | sym::unchecked_shl
 447             | sym::unchecked_shr
 448             | sym::unchecked_add
 449             | sym::unchecked_sub
 450             | sym::unchecked_mul
 451             | sym::exact_div
 452             | sym::rotate_left
 453             | sym::rotate_right
 454             | sym::saturating_add
 455             | sym::saturating_sub => {
 456                 let ty = arg_tys[0];
 457                 match int_type_width_signed(ty, self) {
 458                     Some((width, signed)) => match name {
 459                         sym::ctlz | sym::cttz => {
 460                             let y = self.const_bool(false);
 461                             let llfn = self.get_intrinsic(&format!("llvm.{}.i{}", name, width));
 462                             self.call(llfn, &[args[0].immediate(), y], None)
 463                         }
 464                         sym::ctlz_nonzero | sym::cttz_nonzero => {
 465                             let y = self.const_bool(true);
 466                             let llvm_name = &format!("llvm.{}.i{}", &name_str[..4], width);
 467                             let llfn = self.get_intrinsic(llvm_name);
 468                             self.call(llfn, &[args[0].immediate(), y], None)
 469                         }
 470                         sym::ctpop => self.call(
 471                             self.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 472                             &[args[0].immediate()],
 473                             None,
 474                         ),
 475                         sym::bswap => {
 476                             if width == 8 {
 477                                 args[0].immediate() // byte swap a u8/i8 is just a no-op
 478                             } else {
 479                                 self.call(
 480                                     self.get_intrinsic(&format!("llvm.bswap.i{}", width)),
 481                                     &[args[0].immediate()],
 482                                     None,
 483                                 )
 484                             }
 485                         }
 486                         sym::bitreverse => self.call(
 487                             self.get_intrinsic(&format!("llvm.bitreverse.i{}", width)),
 488                             &[args[0].immediate()],
 489                             None,
 490                         ),
 491                         sym::add_with_overflow
 492                         | sym::sub_with_overflow
 493                         | sym::mul_with_overflow => {
 494                             let intrinsic = format!(
 495                                 "llvm.{}{}.with.overflow.i{}",
 496                                 if signed { 's' } else { 'u' },
 497                                 &name_str[..3],
 498                                 width
 499                             );
 500                             let llfn = self.get_intrinsic(&intrinsic);
 501
 502                             // Convert `i1` to a `bool`, and write it to the out parameter
 503                             let pair =
 504                                 self.call(llfn, &[args[0].immediate(), args[1].immediate()], None);
 505                             let val = self.extract_value(pair, 0);
 506                             let overflow = self.extract_value(pair, 1);
 507                             let overflow = self.zext(overflow, self.type_bool());
 508
 509                             let dest = result.project_field(self, 0);
 510                             self.store(val, dest.llval, dest.align);
 511                             let dest = result.project_field(self, 1);
 512                             self.store(overflow, dest.llval, dest.align);
 513
 514                             return;
 515                         }
 516                         sym::wrapping_add => self.add(args[0].immediate(), args[1].immediate()),
 517                         sym::wrapping_sub => self.sub(args[0].immediate(), args[1].immediate()),
 518                         sym::wrapping_mul => self.mul(args[0].immediate(), args[1].immediate()),
 519                         sym::exact_div => {
 520                             if signed {
 521                                 self.exactsdiv(args[0].immediate(), args[1].immediate())
 522                             } else {
 523                                 self.exactudiv(args[0].immediate(), args[1].immediate())
 524                             }
 525                         }
 526                         sym::unchecked_div => {
 527                             if signed {
 528                                 self.sdiv(args[0].immediate(), args[1].immediate())
 529                             } else {
 530                                 self.udiv(args[0].immediate(), args[1].immediate())
 531                             }
 532                         }
 533                         sym::unchecked_rem => {
 534                             if signed {
 535                                 self.srem(args[0].immediate(), args[1].immediate())
 536                             } else {
 537                                 self.urem(args[0].immediate(), args[1].immediate())
 538                             }
 539                         }
 540                         sym::unchecked_shl => self.shl(args[0].immediate(), args[1].immediate()),
 541                         sym::unchecked_shr => {
 542                             if signed {
 543                                 self.ashr(args[0].immediate(), args[1].immediate())
 544                             } else {
 545                                 self.lshr(args[0].immediate(), args[1].immediate())
 546                             }
 547                         }
 548                         sym::unchecked_add => {
 549                             if signed {
 550                                 self.unchecked_sadd(args[0].immediate(), args[1].immediate())
 551                             } else {
 552                                 self.unchecked_uadd(args[0].immediate(), args[1].immediate())
 553                             }
 554                         }
 555                         sym::unchecked_sub => {
 556                             if signed {
 557                                 self.unchecked_ssub(args[0].immediate(), args[1].immediate())
 558                             } else {
 559                                 self.unchecked_usub(args[0].immediate(), args[1].immediate())
 560                             }
 561                         }
 562                         sym::unchecked_mul => {
 563                             if signed {
 564                                 self.unchecked_smul(args[0].immediate(), args[1].immediate())
 565                             } else {
 566                                 self.unchecked_umul(args[0].immediate(), args[1].immediate())
 567                             }
 568                         }
 569                         sym::rotate_left | sym::rotate_right => {
 570                             let is_left = name == sym::rotate_left;
 571                             let val = args[0].immediate();
 572                             let raw_shift = args[1].immediate();
 573                             // rotate = funnel shift with first two args the same
 574                             let llvm_name =
 575                                 &format!("llvm.fsh{}.i{}", if is_left { 'l' } else { 'r' }, width);
 576                             let llfn = self.get_intrinsic(llvm_name);
 577                             self.call(llfn, &[val, val, raw_shift], None)
 578                         }
 579                         sym::saturating_add | sym::saturating_sub => {
 580                             let is_add = name == sym::saturating_add;
 581                             let lhs = args[0].immediate();
 582                             let rhs = args[1].immediate();
 583                             let llvm_name = &format!(
 584                                 "llvm.{}{}.sat.i{}",
 585                                 if signed { 's' } else { 'u' },
 586                                 if is_add { "add" } else { "sub" },
 587                                 width
 588                             );
 589                             let llfn = self.get_intrinsic(llvm_name);
 590                             self.call(llfn, &[lhs, rhs], None)
 591                         }
 592                         _ => bug!(),
 593                     },
 594                     None => {
 595                         span_invalid_monomorphization_error(
 596                             tcx.sess,
 597                             span,
 598                             &format!(
 599                                 "invalid monomorphization of `{}` intrinsic: \
 600                                       expected basic integer type, found `{}`",
 601                                 name, ty
 602                             ),
 603                         );
 604                         return;
 605                     }
 606                 }
 607             }
 608             sym::fadd_fast | sym::fsub_fast | sym::fmul_fast | sym::fdiv_fast | sym::frem_fast => {
 609                 match float_type_width(arg_tys[0]) {
 610                     Some(_width) => match name {
 611                         sym::fadd_fast => self.fadd_fast(args[0].immediate(), args[1].immediate()),
 612                         sym::fsub_fast => self.fsub_fast(args[0].immediate(), args[1].immediate()),
 613                         sym::fmul_fast => self.fmul_fast(args[0].immediate(), args[1].immediate()),
 614                         sym::fdiv_fast => self.fdiv_fast(args[0].immediate(), args[1].immediate()),
 615                         sym::frem_fast => self.frem_fast(args[0].immediate(), args[1].immediate()),
 616                         _ => bug!(),
 617                     },
 618                     None => {
 619                         span_invalid_monomorphization_error(
 620                             tcx.sess,
 621                             span,
 622                             &format!(
 623                                 "invalid monomorphization of `{}` intrinsic: \
 624                                       expected basic float type, found `{}`",
 625                                 name, arg_tys[0]
 626                             ),
 627                         );
 628                         return;
 629                     }
 630                 }
 631             }
 632
 633             sym::float_to_int_unchecked => {
 634                 if float_type_width(arg_tys[0]).is_none() {
 635                     span_invalid_monomorphization_error(
 636                         tcx.sess,
 637                         span,
 638                         &format!(
 639                             "invalid monomorphization of `float_to_int_unchecked` \
 640                                   intrinsic: expected basic float type, \
 641                                   found `{}`",
 642                             arg_tys[0]
 643                         ),
 644                     );
 645                     return;
 646                 }
 647                 let (width, signed) = match int_type_width_signed(ret_ty, self.cx) {
 648                     Some(pair) => pair,
 649                     None => {
 650                         span_invalid_monomorphization_error(
 651                             tcx.sess,
 652                             span,
 653                             &format!(
 654                                 "invalid monomorphization of `float_to_int_unchecked` \
 655                                       intrinsic:  expected basic integer type, \
 656                                       found `{}`",
 657                                 ret_ty
 658                             ),
 659                         );
 660                         return;
 661                     }
 662                 };
 663                 if signed {
 664                     self.fptosi(args[0].immediate(), self.cx.type_ix(width))
 665                 } else {
 666                     self.fptoui(args[0].immediate(), self.cx.type_ix(width))
 667                 }
 668             }
 669
 670             sym::discriminant_value => {
 671                 if ret_ty.is_integral() {
 672                     args[0].deref(self.cx()).codegen_get_discr(self, ret_ty)
 673                 } else {
 674                     span_bug!(span, "Invalid discriminant type for `{:?}`", arg_tys[0])
 675                 }
 676             }
 677
 678             _ if name_str.starts_with("simd_") => {
 679                 match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
 680                     Ok(llval) => llval,
 681                     Err(()) => return,
 682                 }
 683             }
 684             // This requires that atomic intrinsics follow a specific naming pattern:
 685             // "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
 686             name if name_str.starts_with("atomic_") => {
 687                 use rustc_codegen_ssa::common::AtomicOrdering::*;
 688                 use rustc_codegen_ssa::common::{AtomicRmwBinOp, SynchronizationScope};
 689
 690                 let split: Vec<&str> = name_str.split('_').collect();
 691
 692                 let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
 693                 let (order, failorder) = match split.len() {
 694                     2 => (SequentiallyConsistent, SequentiallyConsistent),
 695                     3 => match split[2] {
 696                         "unordered" => (Unordered, Unordered),
 697                         "relaxed" => (Monotonic, Monotonic),
 698                         "acq" => (Acquire, Acquire),
 699                         "rel" => (Release, Monotonic),
 700                         "acqrel" => (AcquireRelease, Acquire),
 701                         "failrelaxed" if is_cxchg => (SequentiallyConsistent, Monotonic),
 702                         "failacq" if is_cxchg => (SequentiallyConsistent, Acquire),
 703                         _ => self.sess().fatal("unknown ordering in atomic intrinsic"),
 704                     },
 705                     4 => match (split[2], split[3]) {
 706                         ("acq", "failrelaxed") if is_cxchg => (Acquire, Monotonic),
 707                         ("acqrel", "failrelaxed") if is_cxchg => (AcquireRelease, Monotonic),
 708                         _ => self.sess().fatal("unknown ordering in atomic intrinsic"),
 709                     },
 710                     _ => self.sess().fatal("Atomic intrinsic not in correct format"),
 711                 };
 712
 713                 let invalid_monomorphization = |ty| {
 714                     span_invalid_monomorphization_error(
 715                         tcx.sess,
 716                         span,
 717                         &format!(
 718                             "invalid monomorphization of `{}` intrinsic: \
 719                                   expected basic integer type, found `{}`",
 720                             name, ty
 721                         ),
 722                     );
 723                 };
 724
 725                 match split[1] {
 726                     "cxchg" | "cxchgweak" => {
 727                         let ty = substs.type_at(0);
 728                         if int_type_width_signed(ty, self).is_some() {
 729                             let weak = split[1] == "cxchgweak";
 730                             let pair = self.atomic_cmpxchg(
 731                                 args[0].immediate(),
 732                                 args[1].immediate(),
 733                                 args[2].immediate(),
 734                                 order,
 735                                 failorder,
 736                                 weak,
 737                             );
 738                             let val = self.extract_value(pair, 0);
 739                             let success = self.extract_value(pair, 1);
 740                             let success = self.zext(success, self.type_bool());
 741
 742                             let dest = result.project_field(self, 0);
 743                             self.store(val, dest.llval, dest.align);
 744                             let dest = result.project_field(self, 1);
 745                             self.store(success, dest.llval, dest.align);
 746                             return;
 747                         } else {
 748                             return invalid_monomorphization(ty);
 749                         }
 750                     }
 751
 752                     "load" => {
 753                         let ty = substs.type_at(0);
 754                         if int_type_width_signed(ty, self).is_some() {
 755                             let size = self.size_of(ty);
 756                             self.atomic_load(args[0].immediate(), order, size)
 757                         } else {
 758                             return invalid_monomorphization(ty);
 759                         }
 760                     }
 761
 762                     "store" => {
 763                         let ty = substs.type_at(0);
 764                         if int_type_width_signed(ty, self).is_some() {
 765                             let size = self.size_of(ty);
 766                             self.atomic_store(
 767                                 args[1].immediate(),
 768                                 args[0].immediate(),
 769                                 order,
 770                                 size,
 771                             );
 772                             return;
 773                         } else {
 774                             return invalid_monomorphization(ty);
 775                         }
 776                     }
 777
 778                     "fence" => {
 779                         self.atomic_fence(order, SynchronizationScope::CrossThread);
 780                         return;
 781                     }
 782
 783                     "singlethreadfence" => {
 784                         self.atomic_fence(order, SynchronizationScope::SingleThread);
 785                         return;
 786                     }
 787
 788                     // These are all AtomicRMW ops
 789                     op => {
 790                         let atom_op = match op {
 791                             "xchg" => AtomicRmwBinOp::AtomicXchg,
 792                             "xadd" => AtomicRmwBinOp::AtomicAdd,
 793                             "xsub" => AtomicRmwBinOp::AtomicSub,
 794                             "and" => AtomicRmwBinOp::AtomicAnd,
 795                             "nand" => AtomicRmwBinOp::AtomicNand,
 796                             "or" => AtomicRmwBinOp::AtomicOr,
 797                             "xor" => AtomicRmwBinOp::AtomicXor,
 798                             "max" => AtomicRmwBinOp::AtomicMax,
 799                             "min" => AtomicRmwBinOp::AtomicMin,
 800                             "umax" => AtomicRmwBinOp::AtomicUMax,
 801                             "umin" => AtomicRmwBinOp::AtomicUMin,
 802                             _ => self.sess().fatal("unknown atomic operation"),
 803                         };
 804
 805                         let ty = substs.type_at(0);
 806                         if int_type_width_signed(ty, self).is_some() {
 807                             self.atomic_rmw(
 808                                 atom_op,
 809                                 args[0].immediate(),
 810                                 args[1].immediate(),
 811                                 order,
 812                             )
 813                         } else {
 814                             return invalid_monomorphization(ty);
 815                         }
 816                     }
 817                 }
 818             }
 819
 820             sym::nontemporal_store => {
 821                 let dst = args[0].deref(self.cx());
 822                 args[1].val.nontemporal_store(self, dst);
 823                 return;
 824             }
 825
 826             sym::ptr_guaranteed_eq | sym::ptr_guaranteed_ne => {
 827                 let a = args[0].immediate();
 828                 let b = args[1].immediate();
 829                 if name == sym::ptr_guaranteed_eq {
 830                     self.icmp(IntPredicate::IntEQ, a, b)
 831                 } else {
 832                     self.icmp(IntPredicate::IntNE, a, b)
 833                 }
 834             }
 835
 836             sym::ptr_offset_from => {
 837                 let ty = substs.type_at(0);
 838                 let pointee_size = self.size_of(ty);
 839
 840                 // This is the same sequence that Clang emits for pointer subtraction.
 841                 // It can be neither `nsw` nor `nuw` because the input is treated as
 842                 // unsigned but then the output is treated as signed, so neither works.
 843                 let a = args[0].immediate();
 844                 let b = args[1].immediate();
 845                 let a = self.ptrtoint(a, self.type_isize());
 846                 let b = self.ptrtoint(b, self.type_isize());
 847                 let d = self.sub(a, b);
 848                 let pointee_size = self.const_usize(pointee_size.bytes());
 849                 // this is where the signed magic happens (notice the `s` in `exactsdiv`)
 850                 self.exactsdiv(d, pointee_size)
 851             }
 852
 853             _ => bug!("unknown intrinsic '{}'", name),
 854         };
 855
 856         if !fn_abi.ret.is_ignore() {
 857             if let PassMode::Cast(ty) = fn_abi.ret.mode {
 858                 let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
 859                 let ptr = self.pointercast(result.llval, ptr_llty);
 860                 self.store(llval, ptr, result.align);
 861             } else {
 862                 OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
 863                     .val
 864                     .store(self, result);
 865             }
 866         }
 867     }
 868
 869     fn abort(&mut self) {
 870         let fnname = self.get_intrinsic(&("llvm.trap"));
 871         self.call(fnname, &[], None);
 872     }
 873
 874     fn assume(&mut self, val: Self::Value) {
 875         let assume_intrinsic = self.get_intrinsic("llvm.assume");
 876         self.call(assume_intrinsic, &[val], None);
 877     }
 878
 879     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value {
 880         let expect = self.get_intrinsic(&"llvm.expect.i1");
 881         self.call(expect, &[cond, self.const_bool(expected)], None)
 882     }
 883
 884     fn sideeffect(&mut self) {
 885         if self.tcx.sess.opts.debugging_opts.insert_sideeffect {
 886             let fnname = self.get_intrinsic(&("llvm.sideeffect"));
 887             self.call(fnname, &[], None);
 888         }
 889     }
 890
 891     fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {
 892         let intrinsic = self.cx().get_intrinsic("llvm.va_start");
 893         self.call(intrinsic, &[va_list], None)
 894     }
 895
 896     fn va_end(&mut self, va_list: &'ll Value) -> &'ll Value {
 897         let intrinsic = self.cx().get_intrinsic("llvm.va_end");
 898         self.call(intrinsic, &[va_list], None)
 899     }
 900 }
 901
 902 fn copy_intrinsic(
 903     bx: &mut Builder<'a, 'll, 'tcx>,
 904     allow_overlap: bool,
 905     volatile: bool,
 906     ty: Ty<'tcx>,
 907     dst: &'ll Value,
 908     src: &'ll Value,
 909     count: &'ll Value,
 910 ) {
 911     let (size, align) = bx.size_and_align_of(ty);
 912     let size = bx.mul(bx.const_usize(size.bytes()), count);
 913     let flags = if volatile { MemFlags::VOLATILE } else { MemFlags::empty() };
 914     if allow_overlap {
 915         bx.memmove(dst, align, src, align, size, flags);
 916     } else {
 917         bx.memcpy(dst, align, src, align, size, flags);
 918     }
 919 }
 920
 921 fn memset_intrinsic(
 922     bx: &mut Builder<'a, 'll, 'tcx>,
 923     volatile: bool,
 924     ty: Ty<'tcx>,
 925     dst: &'ll Value,
 926     val: &'ll Value,
 927     count: &'ll Value,
 928 ) {
 929     let (size, align) = bx.size_and_align_of(ty);
 930     let size = bx.mul(bx.const_usize(size.bytes()), count);
 931     let flags = if volatile { MemFlags::VOLATILE } else { MemFlags::empty() };
 932     bx.memset(dst, val, size, align, flags);
 933 }
 934
 935 fn try_intrinsic(
 936     bx: &mut Builder<'a, 'll, 'tcx>,
 937     try_func: &'ll Value,
 938     data: &'ll Value,
 939     catch_func: &'ll Value,
 940     dest: &'ll Value,
 941 ) {
 942     if bx.sess().panic_strategy() == PanicStrategy::Abort {
 943         bx.call(try_func, &[data], None);
 944         // Return 0 unconditionally from the intrinsic call;
 945         // we can never unwind.
 946         let ret_align = bx.tcx().data_layout.i32_align.abi;
 947         bx.store(bx.const_i32(0), dest, ret_align);
 948     } else if wants_msvc_seh(bx.sess()) {
 949         codegen_msvc_try(bx, try_func, data, catch_func, dest);
 950     } else {
 951         codegen_gnu_try(bx, try_func, data, catch_func, dest);
 952     }
 953 }
 954
 955 // MSVC's definition of the `rust_try` function.
 956 //
 957 // This implementation uses the new exception handling instructions in LLVM
 958 // which have support in LLVM for SEH on MSVC targets. Although these
 959 // instructions are meant to work for all targets, as of the time of this
 960 // writing, however, LLVM does not recommend the usage of these new instructions
 961 // as the old ones are still more optimized.
 962 fn codegen_msvc_try(
 963     bx: &mut Builder<'a, 'll, 'tcx>,
 964     try_func: &'ll Value,
 965     data: &'ll Value,
 966     catch_func: &'ll Value,
 967     dest: &'ll Value,
 968 ) {
 969     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 970         bx.set_personality_fn(bx.eh_personality());
 971         bx.sideeffect();
 972
 973         let mut normal = bx.build_sibling_block("normal");
 974         let mut catchswitch = bx.build_sibling_block("catchswitch");
 975         let mut catchpad = bx.build_sibling_block("catchpad");
 976         let mut caught = bx.build_sibling_block("caught");
 977
 978         let try_func = llvm::get_param(bx.llfn(), 0);
 979         let data = llvm::get_param(bx.llfn(), 1);
 980         let catch_func = llvm::get_param(bx.llfn(), 2);
 981
 982         // We're generating an IR snippet that looks like:
 983         //
 984         //   declare i32 @rust_try(%try_func, %data, %catch_func) {
 985         //      %slot = alloca u8*
 986         //      invoke %try_func(%data) to label %normal unwind label %catchswitch
 987         //
 988         //   normal:
 989         //      ret i32 0
 990         //
 991         //   catchswitch:
 992         //      %cs = catchswitch within none [%catchpad] unwind to caller
 993         //
 994         //   catchpad:
 995         //      %tok = catchpad within %cs [%type_descriptor, 0, %slot]
 996         //      %ptr = load %slot
 997         //      call %catch_func(%data, %ptr)
 998         //      catchret from %tok to label %caught
 999         //
1000         //   caught:
1001         //      ret i32 1
1002         //   }
1003         //
1004         // This structure follows the basic usage of throw/try/catch in LLVM.
1005         // For example, compile this C++ snippet to see what LLVM generates:
1006         //
1007         //      #include <stdint.h>
1008         //
1009         //      struct rust_panic {
1010         //          rust_panic(const rust_panic&);
1011         //          ~rust_panic();
1012         //
1013         //          uint64_t x[2];
1014         //      };
1015         //
1016         //      int __rust_try(
1017         //          void (*try_func)(void*),
1018         //          void *data,
1019         //          void (*catch_func)(void*, void*) noexcept
1020         //      ) {
1021         //          try {
1022         //              try_func(data);
1023         //              return 0;
1024         //          } catch(rust_panic& a) {
1025         //              catch_func(data, &a);
1026         //              return 1;
1027         //          }
1028         //      }
1029         //
1030         // More information can be found in libstd's seh.rs implementation.
1031         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
1032         let slot = bx.alloca(bx.type_i8p(), ptr_align);
1033         bx.invoke(try_func, &[data], normal.llbb(), catchswitch.llbb(), None);
1034
1035         normal.ret(bx.const_i32(0));
1036
1037         let cs = catchswitch.catch_switch(None, None, 1);
1038         catchswitch.add_handler(cs, catchpad.llbb());
1039
1040         // We can't use the TypeDescriptor defined in libpanic_unwind because it
1041         // might be in another DLL and the SEH encoding only supports specifying
1042         // a TypeDescriptor from the current module.
1043         //
1044         // However this isn't an issue since the MSVC runtime uses string
1045         // comparison on the type name to match TypeDescriptors rather than
1046         // pointer equality.
1047         //
1048         // So instead we generate a new TypeDescriptor in each module that uses
1049         // `try` and let the linker merge duplicate definitions in the same
1050         // module.
1051         //
1052         // When modifying, make sure that the type_name string exactly matches
1053         // the one used in src/libpanic_unwind/seh.rs.
1054         let type_info_vtable = bx.declare_global("??_7type_info@@6B@", bx.type_i8p());
1055         let type_name = bx.const_bytes(b"rust_panic\0");
1056         let type_info =
1057             bx.const_struct(&[type_info_vtable, bx.const_null(bx.type_i8p()), type_name], false);
1058         let tydesc = bx.declare_global("__rust_panic_type_info", bx.val_ty(type_info));
1059         unsafe {
1060             llvm::LLVMRustSetLinkage(tydesc, llvm::Linkage::LinkOnceODRLinkage);
1061             llvm::SetUniqueComdat(bx.llmod, tydesc);
1062             llvm::LLVMSetInitializer(tydesc, type_info);
1063         }
1064
1065         // The flag value of 8 indicates that we are catching the exception by
1066         // reference instead of by value. We can't use catch by value because
1067         // that requires copying the exception object, which we don't support
1068         // since our exception object effectively contains a Box.
1069         //
1070         // Source: MicrosoftCXXABI::getAddrOfCXXCatchHandlerType in clang
1071         let flags = bx.const_i32(8);
1072         let funclet = catchpad.catch_pad(cs, &[tydesc, flags, slot]);
1073         let ptr = catchpad.load(slot, ptr_align);
1074         catchpad.call(catch_func, &[data, ptr], Some(&funclet));
1075
1076         catchpad.catch_ret(&funclet, caught.llbb());
1077
1078         caught.ret(bx.const_i32(1));
1079     });
1080
1081     // Note that no invoke is used here because by definition this function
1082     // can't panic (that's what it's catching).
1083     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
1084     let i32_align = bx.tcx().data_layout.i32_align.abi;
1085     bx.store(ret, dest, i32_align);
1086 }
1087
1088 // Definition of the standard `try` function for Rust using the GNU-like model
1089 // of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
1090 // instructions).
1091 //
1092 // This codegen is a little surprising because we always call a shim
1093 // function instead of inlining the call to `invoke` manually here. This is done
1094 // because in LLVM we're only allowed to have one personality per function
1095 // definition. The call to the `try` intrinsic is being inlined into the
1096 // function calling it, and that function may already have other personality
1097 // functions in play. By calling a shim we're guaranteed that our shim will have
1098 // the right personality function.
1099 fn codegen_gnu_try(
1100     bx: &mut Builder<'a, 'll, 'tcx>,
1101     try_func: &'ll Value,
1102     data: &'ll Value,
1103     catch_func: &'ll Value,
1104     dest: &'ll Value,
1105 ) {
1106     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
1107         // Codegens the shims described above:
1108         //
1109         //   bx:
1110         //      invoke %try_func(%data) normal %normal unwind %catch
1111         //
1112         //   normal:
1113         //      ret 0
1114         //
1115         //   catch:
1116         //      (%ptr, _) = landingpad
1117         //      call %catch_func(%data, %ptr)
1118         //      ret 1
1119
1120         bx.sideeffect();
1121
1122         let mut then = bx.build_sibling_block("then");
1123         let mut catch = bx.build_sibling_block("catch");
1124
1125         let try_func = llvm::get_param(bx.llfn(), 0);
1126         let data = llvm::get_param(bx.llfn(), 1);
1127         let catch_func = llvm::get_param(bx.llfn(), 2);
1128         bx.invoke(try_func, &[data], then.llbb(), catch.llbb(), None);
1129         then.ret(bx.const_i32(0));
1130
1131         // Type indicator for the exception being thrown.
1132         //
1133         // The first value in this tuple is a pointer to the exception object
1134         // being thrown.  The second value is a "selector" indicating which of
1135         // the landing pad clauses the exception's type had been matched to.
1136         // rust_try ignores the selector.
1137         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
1138         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 1);
1139         let tydesc = match bx.tcx().lang_items().eh_catch_typeinfo() {
1140             Some(tydesc) => {
1141                 let tydesc = bx.get_static(tydesc);
1142                 bx.bitcast(tydesc, bx.type_i8p())
1143             }
1144             None => bx.const_null(bx.type_i8p()),
1145         };
1146         catch.add_clause(vals, tydesc);
1147         let ptr = catch.extract_value(vals, 0);
1148         catch.call(catch_func, &[data, ptr], None);
1149         catch.ret(bx.const_i32(1));
1150     });
1151
1152     // Note that no invoke is used here because by definition this function
1153     // can't panic (that's what it's catching).
1154     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
1155     let i32_align = bx.tcx().data_layout.i32_align.abi;
1156     bx.store(ret, dest, i32_align);
1157 }
1158
1159 // Helper function to give a Block to a closure to codegen a shim function.
1160 // This is currently primarily used for the `try` intrinsic functions above.
1161 fn gen_fn<'ll, 'tcx>(
1162     cx: &CodegenCx<'ll, 'tcx>,
1163     name: &str,
1164     inputs: Vec<Ty<'tcx>>,
1165     output: Ty<'tcx>,
1166     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1167 ) -> &'ll Value {
1168     let rust_fn_sig = ty::Binder::bind(cx.tcx.mk_fn_sig(
1169         inputs.into_iter(),
1170         output,
1171         false,
1172         hir::Unsafety::Unsafe,
1173         Abi::Rust,
1174     ));
1175     let fn_abi = FnAbi::of_fn_ptr(cx, rust_fn_sig, &[]);
1176     let llfn = cx.declare_fn(name, &fn_abi);
1177     cx.set_frame_pointer_elimination(llfn);
1178     cx.apply_target_cpu_attr(llfn);
1179     // FIXME(eddyb) find a nicer way to do this.
1180     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
1181     let bx = Builder::new_block(cx, llfn, "entry-block");
1182     codegen(bx);
1183     llfn
1184 }
1185
1186 // Helper function used to get a handle to the `__rust_try` function used to
1187 // catch exceptions.
1188 //
1189 // This function is only generated once and is then cached.
1190 fn get_rust_try_fn<'ll, 'tcx>(
1191     cx: &CodegenCx<'ll, 'tcx>,
1192     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1193 ) -> &'ll Value {
1194     if let Some(llfn) = cx.rust_try_fn.get() {
1195         return llfn;
1196     }
1197
1198     // Define the type up front for the signature of the rust_try function.
1199     let tcx = cx.tcx;
1200     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
1201     let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
1202         iter::once(i8p),
1203         tcx.mk_unit(),
1204         false,
1205         hir::Unsafety::Unsafe,
1206         Abi::Rust,
1207     )));
1208     let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
1209         [i8p, i8p].iter().cloned(),
1210         tcx.mk_unit(),
1211         false,
1212         hir::Unsafety::Unsafe,
1213         Abi::Rust,
1214     )));
1215     let output = tcx.types.i32;
1216     let rust_try = gen_fn(cx, "__rust_try", vec![try_fn_ty, i8p, catch_fn_ty], output, codegen);
1217     cx.rust_try_fn.set(Some(rust_try));
1218     rust_try
1219 }
1220
1221 fn generic_simd_intrinsic(
1222     bx: &mut Builder<'a, 'll, 'tcx>,
1223     name: Symbol,
1224     callee_ty: Ty<'tcx>,
1225     args: &[OperandRef<'tcx, &'ll Value>],
1226     ret_ty: Ty<'tcx>,
1227     llret_ty: &'ll Type,
1228     span: Span,
1229 ) -> Result<&'ll Value, ()> {
1230     // macros for error handling:
1231     macro_rules! emit_error {
1232         ($msg: tt) => {
1233             emit_error!($msg, )
1234         };
1235         ($msg: tt, $($fmt: tt)*) => {
1236             span_invalid_monomorphization_error(
1237                 bx.sess(), span,
1238                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1239                          name, $($fmt)*));
1240         }
1241     }
1242
1243     macro_rules! return_error {
1244         ($($fmt: tt)*) => {
1245             {
1246                 emit_error!($($fmt)*);
1247                 return Err(());
1248             }
1249         }
1250     }
1251
1252     macro_rules! require {
1253         ($cond: expr, $($fmt: tt)*) => {
1254             if !$cond {
1255                 return_error!($($fmt)*);
1256             }
1257         };
1258     }
1259
1260     macro_rules! require_simd {
1261         ($ty: expr, $position: expr) => {
1262             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
1263         };
1264     }
1265
1266     let tcx = bx.tcx();
1267     let sig = tcx
1268         .normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &callee_ty.fn_sig(tcx));
1269     let arg_tys = sig.inputs();
1270     let name_str = &*name.as_str();
1271
1272     if name == sym::simd_select_bitmask {
1273         let in_ty = arg_tys[0];
1274         let m_len = match in_ty.kind {
1275             // Note that this `.unwrap()` crashes for isize/usize, that's sort
1276             // of intentional as there's not currently a use case for that.
1277             ty::Int(i) => i.bit_width().unwrap(),
1278             ty::Uint(i) => i.bit_width().unwrap(),
1279             _ => return_error!("`{}` is not an integral type", in_ty),
1280         };
1281         require_simd!(arg_tys[1], "argument");
1282         let v_len = arg_tys[1].simd_size(tcx);
1283         require!(
1284             m_len == v_len,
1285             "mismatched lengths: mask length `{}` != other vector length `{}`",
1286             m_len,
1287             v_len
1288         );
1289         let i1 = bx.type_i1();
1290         let i1xn = bx.type_vector(i1, m_len);
1291         let m_i1s = bx.bitcast(args[0].immediate(), i1xn);
1292         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1293     }
1294
1295     // every intrinsic below takes a SIMD vector as its first argument
1296     require_simd!(arg_tys[0], "input");
1297     let in_ty = arg_tys[0];
1298     let in_elem = arg_tys[0].simd_type(tcx);
1299     let in_len = arg_tys[0].simd_size(tcx);
1300
1301     let comparison = match name {
1302         sym::simd_eq => Some(hir::BinOpKind::Eq),
1303         sym::simd_ne => Some(hir::BinOpKind::Ne),
1304         sym::simd_lt => Some(hir::BinOpKind::Lt),
1305         sym::simd_le => Some(hir::BinOpKind::Le),
1306         sym::simd_gt => Some(hir::BinOpKind::Gt),
1307         sym::simd_ge => Some(hir::BinOpKind::Ge),
1308         _ => None,
1309     };
1310
1311     if let Some(cmp_op) = comparison {
1312         require_simd!(ret_ty, "return");
1313
1314         let out_len = ret_ty.simd_size(tcx);
1315         require!(
1316             in_len == out_len,
1317             "expected return type with length {} (same as input type `{}`), \
1318                   found `{}` with length {}",
1319             in_len,
1320             in_ty,
1321             ret_ty,
1322             out_len
1323         );
1324         require!(
1325             bx.type_kind(bx.element_type(llret_ty)) == TypeKind::Integer,
1326             "expected return type with integer elements, found `{}` with non-integer `{}`",
1327             ret_ty,
1328             ret_ty.simd_type(tcx)
1329         );
1330
1331         return Ok(compare_simd_types(
1332             bx,
1333             args[0].immediate(),
1334             args[1].immediate(),
1335             in_elem,
1336             llret_ty,
1337             cmp_op,
1338         ));
1339     }
1340
1341     if name_str.starts_with("simd_shuffle") {
1342         let n: u64 = name_str["simd_shuffle".len()..].parse().unwrap_or_else(|_| {
1343             span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
1344         });
1345
1346         require_simd!(ret_ty, "return");
1347
1348         let out_len = ret_ty.simd_size(tcx);
1349         require!(
1350             out_len == n,
1351             "expected return type of length {}, found `{}` with length {}",
1352             n,
1353             ret_ty,
1354             out_len
1355         );
1356         require!(
1357             in_elem == ret_ty.simd_type(tcx),
1358             "expected return element type `{}` (element of input `{}`), \
1359                   found `{}` with element type `{}`",
1360             in_elem,
1361             in_ty,
1362             ret_ty,
1363             ret_ty.simd_type(tcx)
1364         );
1365
1366         let total_len = u128::from(in_len) * 2;
1367
1368         let vector = args[2].immediate();
1369
1370         let indices: Option<Vec<_>> = (0..n)
1371             .map(|i| {
1372                 let arg_idx = i;
1373                 let val = bx.const_get_elt(vector, i as u64);
1374                 match bx.const_to_opt_u128(val, true) {
1375                     None => {
1376                         emit_error!("shuffle index #{} is not a constant", arg_idx);
1377                         None
1378                     }
1379                     Some(idx) if idx >= total_len => {
1380                         emit_error!(
1381                             "shuffle index #{} is out of bounds (limit {})",
1382                             arg_idx,
1383                             total_len
1384                         );
1385                         None
1386                     }
1387                     Some(idx) => Some(bx.const_i32(idx as i32)),
1388                 }
1389             })
1390             .collect();
1391         let indices = match indices {
1392             Some(i) => i,
1393             None => return Ok(bx.const_null(llret_ty)),
1394         };
1395
1396         return Ok(bx.shuffle_vector(
1397             args[0].immediate(),
1398             args[1].immediate(),
1399             bx.const_vector(&indices),
1400         ));
1401     }
1402
1403     if name == sym::simd_insert {
1404         require!(
1405             in_elem == arg_tys[2],
1406             "expected inserted type `{}` (element of input `{}`), found `{}`",
1407             in_elem,
1408             in_ty,
1409             arg_tys[2]
1410         );
1411         return Ok(bx.insert_element(
1412             args[0].immediate(),
1413             args[2].immediate(),
1414             args[1].immediate(),
1415         ));
1416     }
1417     if name == sym::simd_extract {
1418         require!(
1419             ret_ty == in_elem,
1420             "expected return type `{}` (element of input `{}`), found `{}`",
1421             in_elem,
1422             in_ty,
1423             ret_ty
1424         );
1425         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()));
1426     }
1427
1428     if name == sym::simd_select {
1429         let m_elem_ty = in_elem;
1430         let m_len = in_len;
1431         require_simd!(arg_tys[1], "argument");
1432         let v_len = arg_tys[1].simd_size(tcx);
1433         require!(
1434             m_len == v_len,
1435             "mismatched lengths: mask length `{}` != other vector length `{}`",
1436             m_len,
1437             v_len
1438         );
1439         match m_elem_ty.kind {
1440             ty::Int(_) => {}
1441             _ => return_error!("mask element type is `{}`, expected `i_`", m_elem_ty),
1442         }
1443         // truncate the mask to a vector of i1s
1444         let i1 = bx.type_i1();
1445         let i1xn = bx.type_vector(i1, m_len as u64);
1446         let m_i1s = bx.trunc(args[0].immediate(), i1xn);
1447         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1448     }
1449
1450     if name == sym::simd_bitmask {
1451         // The `fn simd_bitmask(vector) -> unsigned integer` intrinsic takes a
1452         // vector mask and returns an unsigned integer containing the most
1453         // significant bit (MSB) of each lane.
1454
1455         // If the vector has less than 8 lanes, an u8 is returned with zeroed
1456         // trailing bits.
1457         let expected_int_bits = in_len.max(8);
1458         match ret_ty.kind {
1459             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => (),
1460             _ => return_error!("bitmask `{}`, expected `u{}`", ret_ty, expected_int_bits),
1461         }
1462
1463         // Integer vector <i{in_bitwidth} x in_len>:
1464         let (i_xn, in_elem_bitwidth) = match in_elem.kind {
1465             ty::Int(i) => {
1466                 (args[0].immediate(), i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits()))
1467             }
1468             ty::Uint(i) => {
1469                 (args[0].immediate(), i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits()))
1470             }
1471             _ => return_error!(
1472                 "vector argument `{}`'s element type `{}`, expected integer element type",
1473                 in_ty,
1474                 in_elem
1475             ),
1476         };
1477
1478         // Shift the MSB to the right by "in_elem_bitwidth - 1" into the first bit position.
1479         let shift_indices =
1480             vec![
1481                 bx.cx.const_int(bx.type_ix(in_elem_bitwidth), (in_elem_bitwidth - 1) as _);
1482                 in_len as _
1483             ];
1484         let i_xn_msb = bx.lshr(i_xn, bx.const_vector(shift_indices.as_slice()));
1485         // Truncate vector to an <i1 x N>
1486         let i1xn = bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len));
1487         // Bitcast <i1 x N> to iN:
1488         let i_ = bx.bitcast(i1xn, bx.type_ix(in_len));
1489         // Zero-extend iN to the bitmask type:
1490         return Ok(bx.zext(i_, bx.type_ix(expected_int_bits)));
1491     }
1492
1493     fn simd_simple_float_intrinsic(
1494         name: &str,
1495         in_elem: &::rustc_middle::ty::TyS<'_>,
1496         in_ty: &::rustc_middle::ty::TyS<'_>,
1497         in_len: u64,
1498         bx: &mut Builder<'a, 'll, 'tcx>,
1499         span: Span,
1500         args: &[OperandRef<'tcx, &'ll Value>],
1501     ) -> Result<&'ll Value, ()> {
1502         macro_rules! emit_error {
1503             ($msg: tt) => {
1504                 emit_error!($msg, )
1505             };
1506             ($msg: tt, $($fmt: tt)*) => {
1507                 span_invalid_monomorphization_error(
1508                     bx.sess(), span,
1509                     &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1510                              name, $($fmt)*));
1511             }
1512         }
1513         macro_rules! return_error {
1514             ($($fmt: tt)*) => {
1515                 {
1516                     emit_error!($($fmt)*);
1517                     return Err(());
1518                 }
1519             }
1520         }
1521         let ety = match in_elem.kind {
1522             ty::Float(f) if f.bit_width() == 32 => {
1523                 if in_len < 2 || in_len > 16 {
1524                     return_error!(
1525                         "unsupported floating-point vector `{}` with length `{}` \
1526                          out-of-range [2, 16]",
1527                         in_ty,
1528                         in_len
1529                     );
1530                 }
1531                 "f32"
1532             }
1533             ty::Float(f) if f.bit_width() == 64 => {
1534                 if in_len < 2 || in_len > 8 {
1535                     return_error!(
1536                         "unsupported floating-point vector `{}` with length `{}` \
1537                                    out-of-range [2, 8]",
1538                         in_ty,
1539                         in_len
1540                     );
1541                 }
1542                 "f64"
1543             }
1544             ty::Float(f) => {
1545                 return_error!(
1546                     "unsupported element type `{}` of floating-point vector `{}`",
1547                     f.name_str(),
1548                     in_ty
1549                 );
1550             }
1551             _ => {
1552                 return_error!("`{}` is not a floating-point type", in_ty);
1553             }
1554         };
1555
1556         let llvm_name = &format!("llvm.{0}.v{1}{2}", name, in_len, ety);
1557         let intrinsic = bx.get_intrinsic(&llvm_name);
1558         let c =
1559             bx.call(intrinsic, &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(), None);
1560         unsafe { llvm::LLVMRustSetHasUnsafeAlgebra(c) };
1561         Ok(c)
1562     }
1563
1564     match name {
1565         sym::simd_fsqrt => {
1566             return simd_simple_float_intrinsic("sqrt", in_elem, in_ty, in_len, bx, span, args);
1567         }
1568         sym::simd_fsin => {
1569             return simd_simple_float_intrinsic("sin", in_elem, in_ty, in_len, bx, span, args);
1570         }
1571         sym::simd_fcos => {
1572             return simd_simple_float_intrinsic("cos", in_elem, in_ty, in_len, bx, span, args);
1573         }
1574         sym::simd_fabs => {
1575             return simd_simple_float_intrinsic("fabs", in_elem, in_ty, in_len, bx, span, args);
1576         }
1577         sym::simd_floor => {
1578             return simd_simple_float_intrinsic("floor", in_elem, in_ty, in_len, bx, span, args);
1579         }
1580         sym::simd_ceil => {
1581             return simd_simple_float_intrinsic("ceil", in_elem, in_ty, in_len, bx, span, args);
1582         }
1583         sym::simd_fexp => {
1584             return simd_simple_float_intrinsic("exp", in_elem, in_ty, in_len, bx, span, args);
1585         }
1586         sym::simd_fexp2 => {
1587             return simd_simple_float_intrinsic("exp2", in_elem, in_ty, in_len, bx, span, args);
1588         }
1589         sym::simd_flog10 => {
1590             return simd_simple_float_intrinsic("log10", in_elem, in_ty, in_len, bx, span, args);
1591         }
1592         sym::simd_flog2 => {
1593             return simd_simple_float_intrinsic("log2", in_elem, in_ty, in_len, bx, span, args);
1594         }
1595         sym::simd_flog => {
1596             return simd_simple_float_intrinsic("log", in_elem, in_ty, in_len, bx, span, args);
1597         }
1598         sym::simd_fpowi => {
1599             return simd_simple_float_intrinsic("powi", in_elem, in_ty, in_len, bx, span, args);
1600         }
1601         sym::simd_fpow => {
1602             return simd_simple_float_intrinsic("pow", in_elem, in_ty, in_len, bx, span, args);
1603         }
1604         sym::simd_fma => {
1605             return simd_simple_float_intrinsic("fma", in_elem, in_ty, in_len, bx, span, args);
1606         }
1607         _ => { /* fallthrough */ }
1608     }
1609
1610     // FIXME: use:
1611     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Function.h#L182
1612     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Intrinsics.h#L81
1613     fn llvm_vector_str(elem_ty: Ty<'_>, vec_len: u64, no_pointers: usize) -> String {
1614         let p0s: String = "p0".repeat(no_pointers);
1615         match elem_ty.kind {
1616             ty::Int(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1617             ty::Uint(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1618             ty::Float(v) => format!("v{}{}f{}", vec_len, p0s, v.bit_width()),
1619             _ => unreachable!(),
1620         }
1621     }
1622
1623     fn llvm_vector_ty(
1624         cx: &CodegenCx<'ll, '_>,
1625         elem_ty: Ty<'_>,
1626         vec_len: u64,
1627         mut no_pointers: usize,
1628     ) -> &'ll Type {
1629         // FIXME: use cx.layout_of(ty).llvm_type() ?
1630         let mut elem_ty = match elem_ty.kind {
1631             ty::Int(v) => cx.type_int_from_ty(v),
1632             ty::Uint(v) => cx.type_uint_from_ty(v),
1633             ty::Float(v) => cx.type_float_from_ty(v),
1634             _ => unreachable!(),
1635         };
1636         while no_pointers > 0 {
1637             elem_ty = cx.type_ptr_to(elem_ty);
1638             no_pointers -= 1;
1639         }
1640         cx.type_vector(elem_ty, vec_len)
1641     }
1642
1643     if name == sym::simd_gather {
1644         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
1645         //             mask: <N x i{M}>) -> <N x T>
1646         // * N: number of elements in the input vectors
1647         // * T: type of the element to load
1648         // * M: any integer width is supported, will be truncated to i1
1649
1650         // All types must be simd vector types
1651         require_simd!(in_ty, "first");
1652         require_simd!(arg_tys[1], "second");
1653         require_simd!(arg_tys[2], "third");
1654         require_simd!(ret_ty, "return");
1655
1656         // Of the same length:
1657         require!(
1658             in_len == arg_tys[1].simd_size(tcx),
1659             "expected {} argument with length {} (same as input type `{}`), \
1660                   found `{}` with length {}",
1661             "second",
1662             in_len,
1663             in_ty,
1664             arg_tys[1],
1665             arg_tys[1].simd_size(tcx)
1666         );
1667         require!(
1668             in_len == arg_tys[2].simd_size(tcx),
1669             "expected {} argument with length {} (same as input type `{}`), \
1670                   found `{}` with length {}",
1671             "third",
1672             in_len,
1673             in_ty,
1674             arg_tys[2],
1675             arg_tys[2].simd_size(tcx)
1676         );
1677
1678         // The return type must match the first argument type
1679         require!(ret_ty == in_ty, "expected return type `{}`, found `{}`", in_ty, ret_ty);
1680
1681         // This counts how many pointers
1682         fn ptr_count(t: Ty<'_>) -> usize {
1683             match t.kind {
1684                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1685                 _ => 0,
1686             }
1687         }
1688
1689         // Non-ptr type
1690         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1691             match t.kind {
1692                 ty::RawPtr(p) => non_ptr(p.ty),
1693                 _ => t,
1694             }
1695         }
1696
1697         // The second argument must be a simd vector with an element type that's a pointer
1698         // to the element type of the first argument
1699         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).kind {
1700             ty::RawPtr(p) if p.ty == in_elem => {
1701                 (ptr_count(arg_tys[1].simd_type(tcx)), non_ptr(arg_tys[1].simd_type(tcx)))
1702             }
1703             _ => {
1704                 require!(
1705                     false,
1706                     "expected element type `{}` of second argument `{}` \
1707                                  to be a pointer to the element type `{}` of the first \
1708                                  argument `{}`, found `{}` != `*_ {}`",
1709                     arg_tys[1].simd_type(tcx),
1710                     arg_tys[1],
1711                     in_elem,
1712                     in_ty,
1713                     arg_tys[1].simd_type(tcx),
1714                     in_elem
1715                 );
1716                 unreachable!();
1717             }
1718         };
1719         assert!(pointer_count > 0);
1720         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1721         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1722
1723         // The element type of the third argument must be a signed integer type of any width:
1724         match arg_tys[2].simd_type(tcx).kind {
1725             ty::Int(_) => (),
1726             _ => {
1727                 require!(
1728                     false,
1729                     "expected element type `{}` of third argument `{}` \
1730                                  to be a signed integer type",
1731                     arg_tys[2].simd_type(tcx),
1732                     arg_tys[2]
1733                 );
1734             }
1735         }
1736
1737         // Alignment of T, must be a constant integer value:
1738         let alignment_ty = bx.type_i32();
1739         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1740
1741         // Truncate the mask vector to a vector of i1s:
1742         let (mask, mask_ty) = {
1743             let i1 = bx.type_i1();
1744             let i1xn = bx.type_vector(i1, in_len);
1745             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1746         };
1747
1748         // Type of the vector of pointers:
1749         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1750         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1751
1752         // Type of the vector of elements:
1753         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1754         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1755
1756         let llvm_intrinsic =
1757             format!("llvm.masked.gather.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1758         let f = bx.declare_cfn(
1759             &llvm_intrinsic,
1760             bx.type_func(
1761                 &[llvm_pointer_vec_ty, alignment_ty, mask_ty, llvm_elem_vec_ty],
1762                 llvm_elem_vec_ty,
1763             ),
1764         );
1765         llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
1766         let v = bx.call(f, &[args[1].immediate(), alignment, mask, args[0].immediate()], None);
1767         return Ok(v);
1768     }
1769
1770     if name == sym::simd_scatter {
1771         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
1772         //             mask: <N x i{M}>) -> ()
1773         // * N: number of elements in the input vectors
1774         // * T: type of the element to load
1775         // * M: any integer width is supported, will be truncated to i1
1776
1777         // All types must be simd vector types
1778         require_simd!(in_ty, "first");
1779         require_simd!(arg_tys[1], "second");
1780         require_simd!(arg_tys[2], "third");
1781
1782         // Of the same length:
1783         require!(
1784             in_len == arg_tys[1].simd_size(tcx),
1785             "expected {} argument with length {} (same as input type `{}`), \
1786                   found `{}` with length {}",
1787             "second",
1788             in_len,
1789             in_ty,
1790             arg_tys[1],
1791             arg_tys[1].simd_size(tcx)
1792         );
1793         require!(
1794             in_len == arg_tys[2].simd_size(tcx),
1795             "expected {} argument with length {} (same as input type `{}`), \
1796                   found `{}` with length {}",
1797             "third",
1798             in_len,
1799             in_ty,
1800             arg_tys[2],
1801             arg_tys[2].simd_size(tcx)
1802         );
1803
1804         // This counts how many pointers
1805         fn ptr_count(t: Ty<'_>) -> usize {
1806             match t.kind {
1807                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1808                 _ => 0,
1809             }
1810         }
1811
1812         // Non-ptr type
1813         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1814             match t.kind {
1815                 ty::RawPtr(p) => non_ptr(p.ty),
1816                 _ => t,
1817             }
1818         }
1819
1820         // The second argument must be a simd vector with an element type that's a pointer
1821         // to the element type of the first argument
1822         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).kind {
1823             ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::Mutability::Mut => {
1824                 (ptr_count(arg_tys[1].simd_type(tcx)), non_ptr(arg_tys[1].simd_type(tcx)))
1825             }
1826             _ => {
1827                 require!(
1828                     false,
1829                     "expected element type `{}` of second argument `{}` \
1830                                  to be a pointer to the element type `{}` of the first \
1831                                  argument `{}`, found `{}` != `*mut {}`",
1832                     arg_tys[1].simd_type(tcx),
1833                     arg_tys[1],
1834                     in_elem,
1835                     in_ty,
1836                     arg_tys[1].simd_type(tcx),
1837                     in_elem
1838                 );
1839                 unreachable!();
1840             }
1841         };
1842         assert!(pointer_count > 0);
1843         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1844         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1845
1846         // The element type of the third argument must be a signed integer type of any width:
1847         match arg_tys[2].simd_type(tcx).kind {
1848             ty::Int(_) => (),
1849             _ => {
1850                 require!(
1851                     false,
1852                     "expected element type `{}` of third argument `{}` \
1853                                  to be a signed integer type",
1854                     arg_tys[2].simd_type(tcx),
1855                     arg_tys[2]
1856                 );
1857             }
1858         }
1859
1860         // Alignment of T, must be a constant integer value:
1861         let alignment_ty = bx.type_i32();
1862         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1863
1864         // Truncate the mask vector to a vector of i1s:
1865         let (mask, mask_ty) = {
1866             let i1 = bx.type_i1();
1867             let i1xn = bx.type_vector(i1, in_len);
1868             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1869         };
1870
1871         let ret_t = bx.type_void();
1872
1873         // Type of the vector of pointers:
1874         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1875         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1876
1877         // Type of the vector of elements:
1878         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1879         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1880
1881         let llvm_intrinsic =
1882             format!("llvm.masked.scatter.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1883         let f = bx.declare_cfn(
1884             &llvm_intrinsic,
1885             bx.type_func(&[llvm_elem_vec_ty, llvm_pointer_vec_ty, alignment_ty, mask_ty], ret_t),
1886         );
1887         llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
1888         let v = bx.call(f, &[args[0].immediate(), args[1].immediate(), alignment, mask], None);
1889         return Ok(v);
1890     }
1891
1892     macro_rules! arith_red {
1893         ($name:ident : $integer_reduce:ident, $float_reduce:ident, $ordered:expr, $op:ident,
1894          $identity:expr) => {
1895             if name == sym::$name {
1896                 require!(
1897                     ret_ty == in_elem,
1898                     "expected return type `{}` (element of input `{}`), found `{}`",
1899                     in_elem,
1900                     in_ty,
1901                     ret_ty
1902                 );
1903                 return match in_elem.kind {
1904                     ty::Int(_) | ty::Uint(_) => {
1905                         let r = bx.$integer_reduce(args[0].immediate());
1906                         if $ordered {
1907                             // if overflow occurs, the result is the
1908                             // mathematical result modulo 2^n:
1909                             Ok(bx.$op(args[1].immediate(), r))
1910                         } else {
1911                             Ok(bx.$integer_reduce(args[0].immediate()))
1912                         }
1913                     }
1914                     ty::Float(f) => {
1915                         let acc = if $ordered {
1916                             // ordered arithmetic reductions take an accumulator
1917                             args[1].immediate()
1918                         } else {
1919                             // unordered arithmetic reductions use the identity accumulator
1920                             match f.bit_width() {
1921                                 32 => bx.const_real(bx.type_f32(), $identity),
1922                                 64 => bx.const_real(bx.type_f64(), $identity),
1923                                 v => return_error!(
1924                                     r#"
1925 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
1926                                     sym::$name,
1927                                     in_ty,
1928                                     in_elem,
1929                                     v,
1930                                     ret_ty
1931                                 ),
1932                             }
1933                         };
1934                         Ok(bx.$float_reduce(acc, args[0].immediate()))
1935                     }
1936                     _ => return_error!(
1937                         "unsupported {} from `{}` with element `{}` to `{}`",
1938                         sym::$name,
1939                         in_ty,
1940                         in_elem,
1941                         ret_ty
1942                     ),
1943                 };
1944             }
1945         };
1946     }
1947
1948     arith_red!(simd_reduce_add_ordered: vector_reduce_add, vector_reduce_fadd, true, add, 0.0);
1949     arith_red!(simd_reduce_mul_ordered: vector_reduce_mul, vector_reduce_fmul, true, mul, 1.0);
1950     arith_red!(
1951         simd_reduce_add_unordered: vector_reduce_add,
1952         vector_reduce_fadd_fast,
1953         false,
1954         add,
1955         0.0
1956     );
1957     arith_red!(
1958         simd_reduce_mul_unordered: vector_reduce_mul,
1959         vector_reduce_fmul_fast,
1960         false,
1961         mul,
1962         1.0
1963     );
1964
1965     macro_rules! minmax_red {
1966         ($name:ident: $int_red:ident, $float_red:ident) => {
1967             if name == sym::$name {
1968                 require!(
1969                     ret_ty == in_elem,
1970                     "expected return type `{}` (element of input `{}`), found `{}`",
1971                     in_elem,
1972                     in_ty,
1973                     ret_ty
1974                 );
1975                 return match in_elem.kind {
1976                     ty::Int(_i) => Ok(bx.$int_red(args[0].immediate(), true)),
1977                     ty::Uint(_u) => Ok(bx.$int_red(args[0].immediate(), false)),
1978                     ty::Float(_f) => Ok(bx.$float_red(args[0].immediate())),
1979                     _ => return_error!(
1980                         "unsupported {} from `{}` with element `{}` to `{}`",
1981                         sym::$name,
1982                         in_ty,
1983                         in_elem,
1984                         ret_ty
1985                     ),
1986                 };
1987             }
1988         };
1989     }
1990
1991     minmax_red!(simd_reduce_min: vector_reduce_min, vector_reduce_fmin);
1992     minmax_red!(simd_reduce_max: vector_reduce_max, vector_reduce_fmax);
1993
1994     minmax_red!(simd_reduce_min_nanless: vector_reduce_min, vector_reduce_fmin_fast);
1995     minmax_red!(simd_reduce_max_nanless: vector_reduce_max, vector_reduce_fmax_fast);
1996
1997     macro_rules! bitwise_red {
1998         ($name:ident : $red:ident, $boolean:expr) => {
1999             if name == sym::$name {
2000                 let input = if !$boolean {
2001                     require!(
2002                         ret_ty == in_elem,
2003                         "expected return type `{}` (element of input `{}`), found `{}`",
2004                         in_elem,
2005                         in_ty,
2006                         ret_ty
2007                     );
2008                     args[0].immediate()
2009                 } else {
2010                     match in_elem.kind {
2011                         ty::Int(_) | ty::Uint(_) => {}
2012                         _ => return_error!(
2013                             "unsupported {} from `{}` with element `{}` to `{}`",
2014                             sym::$name,
2015                             in_ty,
2016                             in_elem,
2017                             ret_ty
2018                         ),
2019                     }
2020
2021                     // boolean reductions operate on vectors of i1s:
2022                     let i1 = bx.type_i1();
2023                     let i1xn = bx.type_vector(i1, in_len as u64);
2024                     bx.trunc(args[0].immediate(), i1xn)
2025                 };
2026                 return match in_elem.kind {
2027                     ty::Int(_) | ty::Uint(_) => {
2028                         let r = bx.$red(input);
2029                         Ok(if !$boolean { r } else { bx.zext(r, bx.type_bool()) })
2030                     }
2031                     _ => return_error!(
2032                         "unsupported {} from `{}` with element `{}` to `{}`",
2033                         sym::$name,
2034                         in_ty,
2035                         in_elem,
2036                         ret_ty
2037                     ),
2038                 };
2039             }
2040         };
2041     }
2042
2043     bitwise_red!(simd_reduce_and: vector_reduce_and, false);
2044     bitwise_red!(simd_reduce_or: vector_reduce_or, false);
2045     bitwise_red!(simd_reduce_xor: vector_reduce_xor, false);
2046     bitwise_red!(simd_reduce_all: vector_reduce_and, true);
2047     bitwise_red!(simd_reduce_any: vector_reduce_or, true);
2048
2049     if name == sym::simd_cast {
2050         require_simd!(ret_ty, "return");
2051         let out_len = ret_ty.simd_size(tcx);
2052         require!(
2053             in_len == out_len,
2054             "expected return type with length {} (same as input type `{}`), \
2055                   found `{}` with length {}",
2056             in_len,
2057             in_ty,
2058             ret_ty,
2059             out_len
2060         );
2061         // casting cares about nominal type, not just structural type
2062         let out_elem = ret_ty.simd_type(tcx);
2063
2064         if in_elem == out_elem {
2065             return Ok(args[0].immediate());
2066         }
2067
2068         enum Style {
2069             Float,
2070             Int(/* is signed? */ bool),
2071             Unsupported,
2072         }
2073
2074         let (in_style, in_width) = match in_elem.kind {
2075             // vectors of pointer-sized integers should've been
2076             // disallowed before here, so this unwrap is safe.
2077             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
2078             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
2079             ty::Float(f) => (Style::Float, f.bit_width()),
2080             _ => (Style::Unsupported, 0),
2081         };
2082         let (out_style, out_width) = match out_elem.kind {
2083             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
2084             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
2085             ty::Float(f) => (Style::Float, f.bit_width()),
2086             _ => (Style::Unsupported, 0),
2087         };
2088
2089         match (in_style, out_style) {
2090             (Style::Int(in_is_signed), Style::Int(_)) => {
2091                 return Ok(match in_width.cmp(&out_width) {
2092                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
2093                     Ordering::Equal => args[0].immediate(),
2094                     Ordering::Less => {
2095                         if in_is_signed {
2096                             bx.sext(args[0].immediate(), llret_ty)
2097                         } else {
2098                             bx.zext(args[0].immediate(), llret_ty)
2099                         }
2100                     }
2101                 });
2102             }
2103             (Style::Int(in_is_signed), Style::Float) => {
2104                 return Ok(if in_is_signed {
2105                     bx.sitofp(args[0].immediate(), llret_ty)
2106                 } else {
2107                     bx.uitofp(args[0].immediate(), llret_ty)
2108                 });
2109             }
2110             (Style::Float, Style::Int(out_is_signed)) => {
2111                 return Ok(if out_is_signed {
2112                     bx.fptosi(args[0].immediate(), llret_ty)
2113                 } else {
2114                     bx.fptoui(args[0].immediate(), llret_ty)
2115                 });
2116             }
2117             (Style::Float, Style::Float) => {
2118                 return Ok(match in_width.cmp(&out_width) {
2119                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
2120                     Ordering::Equal => args[0].immediate(),
2121                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty),
2122                 });
2123             }
2124             _ => { /* Unsupported. Fallthrough. */ }
2125         }
2126         require!(
2127             false,
2128             "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
2129             in_ty,
2130             in_elem,
2131             ret_ty,
2132             out_elem
2133         );
2134     }
2135     macro_rules! arith {
2136         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
2137             $(if name == sym::$name {
2138                 match in_elem.kind {
2139                     $($(ty::$p(_))|* => {
2140                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
2141                     })*
2142                     _ => {},
2143                 }
2144                 require!(false,
2145                          "unsupported operation on `{}` with element `{}`",
2146                          in_ty,
2147                          in_elem)
2148             })*
2149         }
2150     }
2151     arith! {
2152         simd_add: Uint, Int => add, Float => fadd;
2153         simd_sub: Uint, Int => sub, Float => fsub;
2154         simd_mul: Uint, Int => mul, Float => fmul;
2155         simd_div: Uint => udiv, Int => sdiv, Float => fdiv;
2156         simd_rem: Uint => urem, Int => srem, Float => frem;
2157         simd_shl: Uint, Int => shl;
2158         simd_shr: Uint => lshr, Int => ashr;
2159         simd_and: Uint, Int => and;
2160         simd_or: Uint, Int => or;
2161         simd_xor: Uint, Int => xor;
2162         simd_fmax: Float => maxnum;
2163         simd_fmin: Float => minnum;
2164
2165     }
2166
2167     if name == sym::simd_saturating_add || name == sym::simd_saturating_sub {
2168         let lhs = args[0].immediate();
2169         let rhs = args[1].immediate();
2170         let is_add = name == sym::simd_saturating_add;
2171         let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
2172         let (signed, elem_width, elem_ty) = match in_elem.kind {
2173             ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_int_from_ty(i)),
2174             ty::Uint(i) => (false, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_uint_from_ty(i)),
2175             _ => {
2176                 return_error!(
2177                     "expected element type `{}` of vector type `{}` \
2178                      to be a signed or unsigned integer type",
2179                     arg_tys[0].simd_type(tcx),
2180                     arg_tys[0]
2181                 );
2182             }
2183         };
2184         let llvm_intrinsic = &format!(
2185             "llvm.{}{}.sat.v{}i{}",
2186             if signed { 's' } else { 'u' },
2187             if is_add { "add" } else { "sub" },
2188             in_len,
2189             elem_width
2190         );
2191         let vec_ty = bx.cx.type_vector(elem_ty, in_len as u64);
2192
2193         let f = bx.declare_cfn(&llvm_intrinsic, bx.type_func(&[vec_ty, vec_ty], vec_ty));
2194         llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
2195         let v = bx.call(f, &[lhs, rhs], None);
2196         return Ok(v);
2197     }
2198
2199     span_bug!(span, "unknown SIMD intrinsic");
2200 }
2201
2202 // Returns the width of an int Ty, and if it's signed or not
2203 // Returns None if the type is not an integer
2204 // FIXME: there’s multiple of this functions, investigate using some of the already existing
2205 // stuffs.
2206 fn int_type_width_signed(ty: Ty<'_>, cx: &CodegenCx<'_, '_>) -> Option<(u64, bool)> {
2207     match ty.kind {
2208         ty::Int(t) => Some((
2209             match t {
2210                 ast::IntTy::Isize => u64::from(cx.tcx.sess.target.ptr_width),
2211                 ast::IntTy::I8 => 8,
2212                 ast::IntTy::I16 => 16,
2213                 ast::IntTy::I32 => 32,
2214                 ast::IntTy::I64 => 64,
2215                 ast::IntTy::I128 => 128,
2216             },
2217             true,
2218         )),
2219         ty::Uint(t) => Some((
2220             match t {
2221                 ast::UintTy::Usize => u64::from(cx.tcx.sess.target.ptr_width),
2222                 ast::UintTy::U8 => 8,
2223                 ast::UintTy::U16 => 16,
2224                 ast::UintTy::U32 => 32,
2225                 ast::UintTy::U64 => 64,
2226                 ast::UintTy::U128 => 128,
2227             },
2228             false,
2229         )),
2230         _ => None,
2231     }
2232 }
2233
2234 // Returns the width of a float Ty
2235 // Returns None if the type is not a float
2236 fn float_type_width(ty: Ty<'_>) -> Option<u64> {
2237     match ty.kind {
2238         ty::Float(t) => Some(t.bit_width()),
2239         _ => None,
2240     }
2241 }
2242
2243 fn op_to_str_slice<'tcx>(op: &Operand<'tcx>) -> &'tcx str {
2244     Operand::value_from_const(op).try_to_str_slice().expect("Value is &str")
2245 }
2246
2247 fn op_to_u32<'tcx>(op: &Operand<'tcx>) -> u32 {
2248     Operand::scalar_from_const(op).to_u32().expect("Scalar is u32")
2249 }
2250
2251 fn op_to_u64<'tcx>(op: &Operand<'tcx>) -> u64 {
2252     Operand::scalar_from_const(op).to_u64().expect("Scalar is u64")
2253 }