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