src/librustc_codegen_llvm/intrinsic.rs

   1 use crate::abi::{Abi, FnAbi, LlvmType, PassMode};
   2 use crate::builder::Builder;
   3 use crate::context::CodegenCx;
   4 use crate::llvm;
   5 use crate::type_::Type;
   6 use crate::type_of::LayoutLlvmExt;
   7 use crate::va_arg::emit_va_arg;
   8 use crate::value::Value;
   9
  10 use log::debug;
  11
  12 use rustc_ast::ast;
  13 use rustc_codegen_ssa::base::{compare_simd_types, to_immediate, wants_msvc_seh};
  14 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
  15 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
  16 use rustc_codegen_ssa::coverageinfo::CounterOp;
  17 use rustc_codegen_ssa::glue;
  18 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
  19 use rustc_codegen_ssa::mir::place::PlaceRef;
  20 use rustc_codegen_ssa::traits::*;
  21 use rustc_codegen_ssa::MemFlags;
  22 use rustc_hir as hir;
  23 use rustc_middle::mir::coverage;
  24 use rustc_middle::mir::Operand;
  25 use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
  26 use rustc_middle::ty::{self, Ty};
  27 use rustc_middle::{bug, span_bug};
  28 use rustc_span::Span;
  29 use rustc_target::abi::{self, HasDataLayout, LayoutOf, Primitive};
  30 use rustc_target::spec::PanicStrategy;
  31
  32 use std::cmp::Ordering;
  33 use std::iter;
  34
  35 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: &str) -> Option<&'ll Value> {
  36     let llvm_name = match name {
  37         "sqrtf32" => "llvm.sqrt.f32",
  38         "sqrtf64" => "llvm.sqrt.f64",
  39         "powif32" => "llvm.powi.f32",
  40         "powif64" => "llvm.powi.f64",
  41         "sinf32" => "llvm.sin.f32",
  42         "sinf64" => "llvm.sin.f64",
  43         "cosf32" => "llvm.cos.f32",
  44         "cosf64" => "llvm.cos.f64",
  45         "powf32" => "llvm.pow.f32",
  46         "powf64" => "llvm.pow.f64",
  47         "expf32" => "llvm.exp.f32",
  48         "expf64" => "llvm.exp.f64",
  49         "exp2f32" => "llvm.exp2.f32",
  50         "exp2f64" => "llvm.exp2.f64",
  51         "logf32" => "llvm.log.f32",
  52         "logf64" => "llvm.log.f64",
  53         "log10f32" => "llvm.log10.f32",
  54         "log10f64" => "llvm.log10.f64",
  55         "log2f32" => "llvm.log2.f32",
  56         "log2f64" => "llvm.log2.f64",
  57         "fmaf32" => "llvm.fma.f32",
  58         "fmaf64" => "llvm.fma.f64",
  59         "fabsf32" => "llvm.fabs.f32",
  60         "fabsf64" => "llvm.fabs.f64",
  61         "minnumf32" => "llvm.minnum.f32",
  62         "minnumf64" => "llvm.minnum.f64",
  63         "maxnumf32" => "llvm.maxnum.f32",
  64         "maxnumf64" => "llvm.maxnum.f64",
  65         "copysignf32" => "llvm.copysign.f32",
  66         "copysignf64" => "llvm.copysign.f64",
  67         "floorf32" => "llvm.floor.f32",
  68         "floorf64" => "llvm.floor.f64",
  69         "ceilf32" => "llvm.ceil.f32",
  70         "ceilf64" => "llvm.ceil.f64",
  71         "truncf32" => "llvm.trunc.f32",
  72         "truncf64" => "llvm.trunc.f64",
  73         "rintf32" => "llvm.rint.f32",
  74         "rintf64" => "llvm.rint.f64",
  75         "nearbyintf32" => "llvm.nearbyint.f32",
  76         "nearbyintf64" => "llvm.nearbyint.f64",
  77         "roundf32" => "llvm.round.f32",
  78         "roundf64" => "llvm.round.f64",
  79         "assume" => "llvm.assume",
  80         "abort" => "llvm.trap",
  81         _ => return None,
  82     };
  83     Some(cx.get_intrinsic(&llvm_name))
  84 }
  85
  86 impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
  87     fn is_codegen_intrinsic(
  88         &mut self,
  89         intrinsic: &str,
  90         args: &Vec<Operand<'tcx>>,
  91         caller_instance: ty::Instance<'tcx>,
  92     ) -> bool {
  93         match intrinsic {
  94             "count_code_region" => {
  95                 use coverage::count_code_region_args::*;
  96                 self.add_counter_region(
  97                     caller_instance,
  98                     op_to_u32(&args[COUNTER_INDEX]),
  99                     op_to_u32(&args[START_BYTE_POS]),
 100                     op_to_u32(&args[END_BYTE_POS]),
 101                 );
 102                 true // Also inject the counter increment in the backend
 103             }
 104             "coverage_counter_add" | "coverage_counter_subtract" => {
 105                 use coverage::coverage_counter_expression_args::*;
 106                 self.add_counter_expression_region(
 107                     caller_instance,
 108                     op_to_u32(&args[COUNTER_EXPRESSION_INDEX]),
 109                     op_to_u32(&args[LEFT_INDEX]),
 110                     if intrinsic == "coverage_counter_add" {
 111                         CounterOp::Add
 112                     } else {
 113                         CounterOp::Subtract
 114                     },
 115                     op_to_u32(&args[RIGHT_INDEX]),
 116                     op_to_u32(&args[START_BYTE_POS]),
 117                     op_to_u32(&args[END_BYTE_POS]),
 118                 );
 119                 false // Does not inject backend code
 120             }
 121             "coverage_unreachable" => {
 122                 use coverage::coverage_unreachable_args::*;
 123                 self.add_unreachable_region(
 124                     caller_instance,
 125                     op_to_u32(&args[START_BYTE_POS]),
 126                     op_to_u32(&args[END_BYTE_POS]),
 127                 );
 128                 false // Does not inject backend code
 129             }
 130             _ => true, // Unhandled intrinsics should be passed to `codegen_intrinsic_call()`
 131         }
 132     }
 133
 134     fn codegen_intrinsic_call(
 135         &mut self,
 136         instance: ty::Instance<'tcx>,
 137         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
 138         args: &[OperandRef<'tcx, &'ll Value>],
 139         llresult: &'ll Value,
 140         span: Span,
 141         caller_instance: ty::Instance<'tcx>,
 142     ) {
 143         let tcx = self.tcx;
 144         let callee_ty = instance.monomorphic_ty(tcx);
 145
 146         let (def_id, substs) = match callee_ty.kind {
 147             ty::FnDef(def_id, substs) => (def_id, substs),
 148             _ => bug!("expected fn item type, found {}", callee_ty),
 149         };
 150
 151         let sig = callee_ty.fn_sig(tcx);
 152         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &sig);
 153         let arg_tys = sig.inputs();
 154         let ret_ty = sig.output();
 155         let name = &*tcx.item_name(def_id).as_str();
 156
 157         let llret_ty = self.layout_of(ret_ty).llvm_type(self);
 158         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 159
 160         let simple = get_simple_intrinsic(self, name);
 161         let llval = match name {
 162             _ if simple.is_some() => self.call(
 163                 simple.unwrap(),
 164                 &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 165                 None,
 166             ),
 167             "unreachable" => {
 168                 return;
 169             }
 170             "likely" => {
 171                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 172                 self.call(expect, &[args[0].immediate(), self.const_bool(true)], None)
 173             }
 174             "unlikely" => {
 175                 let expect = self.get_intrinsic(&("llvm.expect.i1"));
 176                 self.call(expect, &[args[0].immediate(), self.const_bool(false)], None)
 177             }
 178             "try" => {
 179                 try_intrinsic(
 180                     self,
 181                     args[0].immediate(),
 182                     args[1].immediate(),
 183                     args[2].immediate(),
 184                     llresult,
 185                 );
 186                 return;
 187             }
 188             "breakpoint" => {
 189                 let llfn = self.get_intrinsic(&("llvm.debugtrap"));
 190                 self.call(llfn, &[], None)
 191             }
 192             "count_code_region" => {
 193                 // FIXME(richkadel): The current implementation assumes the MIR for the given
 194                 // caller_instance represents a single function. Validate and/or correct if inlining
 195                 // and/or monomorphization invalidates these assumptions.
 196                 let coverageinfo = tcx.coverageinfo(caller_instance.def_id());
 197                 let mangled_fn = tcx.symbol_name(caller_instance);
 198                 let (mangled_fn_name, _len_val) = self.const_str(mangled_fn.name);
 199                 let hash = self.const_u64(coverageinfo.hash);
 200                 let num_counters = self.const_u32(coverageinfo.num_counters);
 201                 use coverage::count_code_region_args::*;
 202                 let index = args[COUNTER_INDEX].immediate();
 203                 debug!(
 204                     "count_code_region to LLVM intrinsic instrprof.increment(fn_name={}, hash={:?}, num_counters={:?}, index={:?})",
 205                     mangled_fn.name, hash, num_counters, index,
 206                 );
 207                 self.instrprof_increment(mangled_fn_name, hash, num_counters, index)
 208             }
 209             "va_start" => self.va_start(args[0].immediate()),
 210             "va_end" => self.va_end(args[0].immediate()),
 211             "va_copy" => {
 212                 let intrinsic = self.cx().get_intrinsic(&("llvm.va_copy"));
 213                 self.call(intrinsic, &[args[0].immediate(), args[1].immediate()], None)
 214             }
 215             "va_arg" => {
 216                 match fn_abi.ret.layout.abi {
 217                     abi::Abi::Scalar(ref scalar) => {
 218                         match scalar.value {
 219                             Primitive::Int(..) => {
 220                                 if self.cx().size_of(ret_ty).bytes() < 4 {
 221                                     // `va_arg` should not be called on a integer type
 222                                     // less than 4 bytes in length. If it is, promote
 223                                     // the integer to a `i32` and truncate the result
 224                                     // back to the smaller type.
 225                                     let promoted_result = emit_va_arg(self, args[0], tcx.types.i32);
 226                                     self.trunc(promoted_result, llret_ty)
 227                                 } else {
 228                                     emit_va_arg(self, args[0], ret_ty)
 229                                 }
 230                             }
 231                             Primitive::F64 | Primitive::Pointer => {
 232                                 emit_va_arg(self, args[0], ret_ty)
 233                             }
 234                             // `va_arg` should never be used with the return type f32.
 235                             Primitive::F32 => bug!("the va_arg intrinsic does not work with `f32`"),
 236                         }
 237                     }
 238                     _ => bug!("the va_arg intrinsic does not work with non-scalar types"),
 239                 }
 240             }
 241             "size_of_val" => {
 242                 let tp_ty = substs.type_at(0);
 243                 if let OperandValue::Pair(_, meta) = args[0].val {
 244                     let (llsize, _) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 245                     llsize
 246                 } else {
 247                     self.const_usize(self.size_of(tp_ty).bytes())
 248                 }
 249             }
 250             "min_align_of_val" => {
 251                 let tp_ty = substs.type_at(0);
 252                 if let OperandValue::Pair(_, meta) = args[0].val {
 253                     let (_, llalign) = glue::size_and_align_of_dst(self, tp_ty, Some(meta));
 254                     llalign
 255                 } else {
 256                     self.const_usize(self.align_of(tp_ty).bytes())
 257                 }
 258             }
 259             "size_of" | "pref_align_of" | "min_align_of" | "needs_drop" | "type_id"
 260             | "type_name" | "variant_count" => {
 261                 let value = self
 262                     .tcx
 263                     .const_eval_instance(ty::ParamEnv::reveal_all(), instance, None)
 264                     .unwrap();
 265                 OperandRef::from_const(self, value, ret_ty).immediate_or_packed_pair(self)
 266             }
 267             // Effectively no-op
 268             "forget" => {
 269                 return;
 270             }
 271             "offset" => {
 272                 let ptr = args[0].immediate();
 273                 let offset = args[1].immediate();
 274                 self.inbounds_gep(ptr, &[offset])
 275             }
 276             "arith_offset" => {
 277                 let ptr = args[0].immediate();
 278                 let offset = args[1].immediate();
 279                 self.gep(ptr, &[offset])
 280             }
 281
 282             "copy_nonoverlapping" => {
 283                 copy_intrinsic(
 284                     self,
 285                     false,
 286                     false,
 287                     substs.type_at(0),
 288                     args[1].immediate(),
 289                     args[0].immediate(),
 290                     args[2].immediate(),
 291                 );
 292                 return;
 293             }
 294             "copy" => {
 295                 copy_intrinsic(
 296                     self,
 297                     true,
 298                     false,
 299                     substs.type_at(0),
 300                     args[1].immediate(),
 301                     args[0].immediate(),
 302                     args[2].immediate(),
 303                 );
 304                 return;
 305             }
 306             "write_bytes" => {
 307                 memset_intrinsic(
 308                     self,
 309                     false,
 310                     substs.type_at(0),
 311                     args[0].immediate(),
 312                     args[1].immediate(),
 313                     args[2].immediate(),
 314                 );
 315                 return;
 316             }
 317
 318             "volatile_copy_nonoverlapping_memory" => {
 319                 copy_intrinsic(
 320                     self,
 321                     false,
 322                     true,
 323                     substs.type_at(0),
 324                     args[0].immediate(),
 325                     args[1].immediate(),
 326                     args[2].immediate(),
 327                 );
 328                 return;
 329             }
 330             "volatile_copy_memory" => {
 331                 copy_intrinsic(
 332                     self,
 333                     true,
 334                     true,
 335                     substs.type_at(0),
 336                     args[0].immediate(),
 337                     args[1].immediate(),
 338                     args[2].immediate(),
 339                 );
 340                 return;
 341             }
 342             "volatile_set_memory" => {
 343                 memset_intrinsic(
 344                     self,
 345                     true,
 346                     substs.type_at(0),
 347                     args[0].immediate(),
 348                     args[1].immediate(),
 349                     args[2].immediate(),
 350                 );
 351                 return;
 352             }
 353             "volatile_load" | "unaligned_volatile_load" => {
 354                 let tp_ty = substs.type_at(0);
 355                 let mut ptr = args[0].immediate();
 356                 if let PassMode::Cast(ty) = fn_abi.ret.mode {
 357                     ptr = self.pointercast(ptr, self.type_ptr_to(ty.llvm_type(self)));
 358                 }
 359                 let load = self.volatile_load(ptr);
 360                 let align = if name == "unaligned_volatile_load" {
 361                     1
 362                 } else {
 363                     self.align_of(tp_ty).bytes() as u32
 364                 };
 365                 unsafe {
 366                     llvm::LLVMSetAlignment(load, align);
 367                 }
 368                 to_immediate(self, load, self.layout_of(tp_ty))
 369             }
 370             "volatile_store" => {
 371                 let dst = args[0].deref(self.cx());
 372                 args[1].val.volatile_store(self, dst);
 373                 return;
 374             }
 375             "unaligned_volatile_store" => {
 376                 let dst = args[0].deref(self.cx());
 377                 args[1].val.unaligned_volatile_store(self, dst);
 378                 return;
 379             }
 380             "prefetch_read_data"
 381             | "prefetch_write_data"
 382             | "prefetch_read_instruction"
 383             | "prefetch_write_instruction" => {
 384                 let expect = self.get_intrinsic(&("llvm.prefetch"));
 385                 let (rw, cache_type) = match name {
 386                     "prefetch_read_data" => (0, 1),
 387                     "prefetch_write_data" => (1, 1),
 388                     "prefetch_read_instruction" => (0, 0),
 389                     "prefetch_write_instruction" => (1, 0),
 390                     _ => bug!(),
 391                 };
 392                 self.call(
 393                     expect,
 394                     &[
 395                         args[0].immediate(),
 396                         self.const_i32(rw),
 397                         args[1].immediate(),
 398                         self.const_i32(cache_type),
 399                     ],
 400                     None,
 401                 )
 402             }
 403             "ctlz" | "ctlz_nonzero" | "cttz" | "cttz_nonzero" | "ctpop" | "bswap"
 404             | "bitreverse" | "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow"
 405             | "wrapping_add" | "wrapping_sub" | "wrapping_mul" | "unchecked_div"
 406             | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" | "unchecked_add"
 407             | "unchecked_sub" | "unchecked_mul" | "exact_div" | "rotate_left" | "rotate_right"
 408             | "saturating_add" | "saturating_sub" => {
 409                 let ty = arg_tys[0];
 410                 match int_type_width_signed(ty, self) {
 411                     Some((width, signed)) => match name {
 412                         "ctlz" | "cttz" => {
 413                             let y = self.const_bool(false);
 414                             let llfn = self.get_intrinsic(&format!("llvm.{}.i{}", name, width));
 415                             self.call(llfn, &[args[0].immediate(), y], None)
 416                         }
 417                         "ctlz_nonzero" | "cttz_nonzero" => {
 418                             let y = self.const_bool(true);
 419                             let llvm_name = &format!("llvm.{}.i{}", &name[..4], width);
 420                             let llfn = self.get_intrinsic(llvm_name);
 421                             self.call(llfn, &[args[0].immediate(), y], None)
 422                         }
 423                         "ctpop" => self.call(
 424                             self.get_intrinsic(&format!("llvm.ctpop.i{}", width)),
 425                             &[args[0].immediate()],
 426                             None,
 427                         ),
 428                         "bswap" => {
 429                             if width == 8 {
 430                                 args[0].immediate() // byte swap a u8/i8 is just a no-op
 431                             } else {
 432                                 self.call(
 433                                     self.get_intrinsic(&format!("llvm.bswap.i{}", width)),
 434                                     &[args[0].immediate()],
 435                                     None,
 436                                 )
 437                             }
 438                         }
 439                         "bitreverse" => self.call(
 440                             self.get_intrinsic(&format!("llvm.bitreverse.i{}", width)),
 441                             &[args[0].immediate()],
 442                             None,
 443                         ),
 444                         "add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" => {
 445                             let intrinsic = format!(
 446                                 "llvm.{}{}.with.overflow.i{}",
 447                                 if signed { 's' } else { 'u' },
 448                                 &name[..3],
 449                                 width
 450                             );
 451                             let llfn = self.get_intrinsic(&intrinsic);
 452
 453                             // Convert `i1` to a `bool`, and write it to the out parameter
 454                             let pair =
 455                                 self.call(llfn, &[args[0].immediate(), args[1].immediate()], None);
 456                             let val = self.extract_value(pair, 0);
 457                             let overflow = self.extract_value(pair, 1);
 458                             let overflow = self.zext(overflow, self.type_bool());
 459
 460                             let dest = result.project_field(self, 0);
 461                             self.store(val, dest.llval, dest.align);
 462                             let dest = result.project_field(self, 1);
 463                             self.store(overflow, dest.llval, dest.align);
 464
 465                             return;
 466                         }
 467                         "wrapping_add" => self.add(args[0].immediate(), args[1].immediate()),
 468                         "wrapping_sub" => self.sub(args[0].immediate(), args[1].immediate()),
 469                         "wrapping_mul" => self.mul(args[0].immediate(), args[1].immediate()),
 470                         "exact_div" => {
 471                             if signed {
 472                                 self.exactsdiv(args[0].immediate(), args[1].immediate())
 473                             } else {
 474                                 self.exactudiv(args[0].immediate(), args[1].immediate())
 475                             }
 476                         }
 477                         "unchecked_div" => {
 478                             if signed {
 479                                 self.sdiv(args[0].immediate(), args[1].immediate())
 480                             } else {
 481                                 self.udiv(args[0].immediate(), args[1].immediate())
 482                             }
 483                         }
 484                         "unchecked_rem" => {
 485                             if signed {
 486                                 self.srem(args[0].immediate(), args[1].immediate())
 487                             } else {
 488                                 self.urem(args[0].immediate(), args[1].immediate())
 489                             }
 490                         }
 491                         "unchecked_shl" => self.shl(args[0].immediate(), args[1].immediate()),
 492                         "unchecked_shr" => {
 493                             if signed {
 494                                 self.ashr(args[0].immediate(), args[1].immediate())
 495                             } else {
 496                                 self.lshr(args[0].immediate(), args[1].immediate())
 497                             }
 498                         }
 499                         "unchecked_add" => {
 500                             if signed {
 501                                 self.unchecked_sadd(args[0].immediate(), args[1].immediate())
 502                             } else {
 503                                 self.unchecked_uadd(args[0].immediate(), args[1].immediate())
 504                             }
 505                         }
 506                         "unchecked_sub" => {
 507                             if signed {
 508                                 self.unchecked_ssub(args[0].immediate(), args[1].immediate())
 509                             } else {
 510                                 self.unchecked_usub(args[0].immediate(), args[1].immediate())
 511                             }
 512                         }
 513                         "unchecked_mul" => {
 514                             if signed {
 515                                 self.unchecked_smul(args[0].immediate(), args[1].immediate())
 516                             } else {
 517                                 self.unchecked_umul(args[0].immediate(), args[1].immediate())
 518                             }
 519                         }
 520                         "rotate_left" | "rotate_right" => {
 521                             let is_left = name == "rotate_left";
 522                             let val = args[0].immediate();
 523                             let raw_shift = args[1].immediate();
 524                             // rotate = funnel shift with first two args the same
 525                             let llvm_name =
 526                                 &format!("llvm.fsh{}.i{}", if is_left { 'l' } else { 'r' }, width);
 527                             let llfn = self.get_intrinsic(llvm_name);
 528                             self.call(llfn, &[val, val, raw_shift], None)
 529                         }
 530                         "saturating_add" | "saturating_sub" => {
 531                             let is_add = name == "saturating_add";
 532                             let lhs = args[0].immediate();
 533                             let rhs = args[1].immediate();
 534                             let llvm_name = &format!(
 535                                 "llvm.{}{}.sat.i{}",
 536                                 if signed { 's' } else { 'u' },
 537                                 if is_add { "add" } else { "sub" },
 538                                 width
 539                             );
 540                             let llfn = self.get_intrinsic(llvm_name);
 541                             self.call(llfn, &[lhs, rhs], None)
 542                         }
 543                         _ => bug!(),
 544                     },
 545                     None => {
 546                         span_invalid_monomorphization_error(
 547                             tcx.sess,
 548                             span,
 549                             &format!(
 550                                 "invalid monomorphization of `{}` intrinsic: \
 551                                       expected basic integer type, found `{}`",
 552                                 name, ty
 553                             ),
 554                         );
 555                         return;
 556                     }
 557                 }
 558             }
 559             "fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" => {
 560                 match float_type_width(arg_tys[0]) {
 561                     Some(_width) => match name {
 562                         "fadd_fast" => self.fadd_fast(args[0].immediate(), args[1].immediate()),
 563                         "fsub_fast" => self.fsub_fast(args[0].immediate(), args[1].immediate()),
 564                         "fmul_fast" => self.fmul_fast(args[0].immediate(), args[1].immediate()),
 565                         "fdiv_fast" => self.fdiv_fast(args[0].immediate(), args[1].immediate()),
 566                         "frem_fast" => self.frem_fast(args[0].immediate(), args[1].immediate()),
 567                         _ => bug!(),
 568                     },
 569                     None => {
 570                         span_invalid_monomorphization_error(
 571                             tcx.sess,
 572                             span,
 573                             &format!(
 574                                 "invalid monomorphization of `{}` intrinsic: \
 575                                       expected basic float type, found `{}`",
 576                                 name, arg_tys[0]
 577                             ),
 578                         );
 579                         return;
 580                     }
 581                 }
 582             }
 583
 584             "float_to_int_unchecked" => {
 585                 if float_type_width(arg_tys[0]).is_none() {
 586                     span_invalid_monomorphization_error(
 587                         tcx.sess,
 588                         span,
 589                         &format!(
 590                             "invalid monomorphization of `float_to_int_unchecked` \
 591                                   intrinsic: expected basic float type, \
 592                                   found `{}`",
 593                             arg_tys[0]
 594                         ),
 595                     );
 596                     return;
 597                 }
 598                 match int_type_width_signed(ret_ty, self.cx) {
 599                     Some((width, signed)) => {
 600                         if signed {
 601                             self.fptosi(args[0].immediate(), self.cx.type_ix(width))
 602                         } else {
 603                             self.fptoui(args[0].immediate(), self.cx.type_ix(width))
 604                         }
 605                     }
 606                     None => {
 607                         span_invalid_monomorphization_error(
 608                             tcx.sess,
 609                             span,
 610                             &format!(
 611                                 "invalid monomorphization of `float_to_int_unchecked` \
 612                                       intrinsic:  expected basic integer type, \
 613                                       found `{}`",
 614                                 ret_ty
 615                             ),
 616                         );
 617                         return;
 618                     }
 619                 }
 620             }
 621
 622             "discriminant_value" => {
 623                 if ret_ty.is_integral() {
 624                     args[0].deref(self.cx()).codegen_get_discr(self, ret_ty)
 625                 } else {
 626                     span_bug!(span, "Invalid discriminant type for `{:?}`", arg_tys[0])
 627                 }
 628             }
 629
 630             name if name.starts_with("simd_") => {
 631                 match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
 632                     Ok(llval) => llval,
 633                     Err(()) => return,
 634                 }
 635             }
 636             // This requires that atomic intrinsics follow a specific naming pattern:
 637             // "atomic_<operation>[_<ordering>]", and no ordering means SeqCst
 638             name if name.starts_with("atomic_") => {
 639                 use rustc_codegen_ssa::common::AtomicOrdering::*;
 640                 use rustc_codegen_ssa::common::{AtomicRmwBinOp, SynchronizationScope};
 641
 642                 let split: Vec<&str> = name.split('_').collect();
 643
 644                 let is_cxchg = split[1] == "cxchg" || split[1] == "cxchgweak";
 645                 let (order, failorder) = match split.len() {
 646                     2 => (SequentiallyConsistent, SequentiallyConsistent),
 647                     3 => match split[2] {
 648                         "unordered" => (Unordered, Unordered),
 649                         "relaxed" => (Monotonic, Monotonic),
 650                         "acq" => (Acquire, Acquire),
 651                         "rel" => (Release, Monotonic),
 652                         "acqrel" => (AcquireRelease, Acquire),
 653                         "failrelaxed" if is_cxchg => (SequentiallyConsistent, Monotonic),
 654                         "failacq" if is_cxchg => (SequentiallyConsistent, Acquire),
 655                         _ => self.sess().fatal("unknown ordering in atomic intrinsic"),
 656                     },
 657                     4 => match (split[2], split[3]) {
 658                         ("acq", "failrelaxed") if is_cxchg => (Acquire, Monotonic),
 659                         ("acqrel", "failrelaxed") if is_cxchg => (AcquireRelease, Monotonic),
 660                         _ => self.sess().fatal("unknown ordering in atomic intrinsic"),
 661                     },
 662                     _ => self.sess().fatal("Atomic intrinsic not in correct format"),
 663                 };
 664
 665                 let invalid_monomorphization = |ty| {
 666                     span_invalid_monomorphization_error(
 667                         tcx.sess,
 668                         span,
 669                         &format!(
 670                             "invalid monomorphization of `{}` intrinsic: \
 671                                   expected basic integer type, found `{}`",
 672                             name, ty
 673                         ),
 674                     );
 675                 };
 676
 677                 match split[1] {
 678                     "cxchg" | "cxchgweak" => {
 679                         let ty = substs.type_at(0);
 680                         if int_type_width_signed(ty, self).is_some() {
 681                             let weak = split[1] == "cxchgweak";
 682                             let pair = self.atomic_cmpxchg(
 683                                 args[0].immediate(),
 684                                 args[1].immediate(),
 685                                 args[2].immediate(),
 686                                 order,
 687                                 failorder,
 688                                 weak,
 689                             );
 690                             let val = self.extract_value(pair, 0);
 691                             let success = self.extract_value(pair, 1);
 692                             let success = self.zext(success, self.type_bool());
 693
 694                             let dest = result.project_field(self, 0);
 695                             self.store(val, dest.llval, dest.align);
 696                             let dest = result.project_field(self, 1);
 697                             self.store(success, dest.llval, dest.align);
 698                             return;
 699                         } else {
 700                             return invalid_monomorphization(ty);
 701                         }
 702                     }
 703
 704                     "load" => {
 705                         let ty = substs.type_at(0);
 706                         if int_type_width_signed(ty, self).is_some() {
 707                             let size = self.size_of(ty);
 708                             self.atomic_load(args[0].immediate(), order, size)
 709                         } else {
 710                             return invalid_monomorphization(ty);
 711                         }
 712                     }
 713
 714                     "store" => {
 715                         let ty = substs.type_at(0);
 716                         if int_type_width_signed(ty, self).is_some() {
 717                             let size = self.size_of(ty);
 718                             self.atomic_store(
 719                                 args[1].immediate(),
 720                                 args[0].immediate(),
 721                                 order,
 722                                 size,
 723                             );
 724                             return;
 725                         } else {
 726                             return invalid_monomorphization(ty);
 727                         }
 728                     }
 729
 730                     "fence" => {
 731                         self.atomic_fence(order, SynchronizationScope::CrossThread);
 732                         return;
 733                     }
 734
 735                     "singlethreadfence" => {
 736                         self.atomic_fence(order, SynchronizationScope::SingleThread);
 737                         return;
 738                     }
 739
 740                     // These are all AtomicRMW ops
 741                     op => {
 742                         let atom_op = match op {
 743                             "xchg" => AtomicRmwBinOp::AtomicXchg,
 744                             "xadd" => AtomicRmwBinOp::AtomicAdd,
 745                             "xsub" => AtomicRmwBinOp::AtomicSub,
 746                             "and" => AtomicRmwBinOp::AtomicAnd,
 747                             "nand" => AtomicRmwBinOp::AtomicNand,
 748                             "or" => AtomicRmwBinOp::AtomicOr,
 749                             "xor" => AtomicRmwBinOp::AtomicXor,
 750                             "max" => AtomicRmwBinOp::AtomicMax,
 751                             "min" => AtomicRmwBinOp::AtomicMin,
 752                             "umax" => AtomicRmwBinOp::AtomicUMax,
 753                             "umin" => AtomicRmwBinOp::AtomicUMin,
 754                             _ => self.sess().fatal("unknown atomic operation"),
 755                         };
 756
 757                         let ty = substs.type_at(0);
 758                         if int_type_width_signed(ty, self).is_some() {
 759                             self.atomic_rmw(
 760                                 atom_op,
 761                                 args[0].immediate(),
 762                                 args[1].immediate(),
 763                                 order,
 764                             )
 765                         } else {
 766                             return invalid_monomorphization(ty);
 767                         }
 768                     }
 769                 }
 770             }
 771
 772             "nontemporal_store" => {
 773                 let dst = args[0].deref(self.cx());
 774                 args[1].val.nontemporal_store(self, dst);
 775                 return;
 776             }
 777
 778             "ptr_guaranteed_eq" | "ptr_guaranteed_ne" => {
 779                 let a = args[0].immediate();
 780                 let b = args[1].immediate();
 781                 if name == "ptr_guaranteed_eq" {
 782                     self.icmp(IntPredicate::IntEQ, a, b)
 783                 } else {
 784                     self.icmp(IntPredicate::IntNE, a, b)
 785                 }
 786             }
 787
 788             "ptr_offset_from" => {
 789                 let ty = substs.type_at(0);
 790                 let pointee_size = self.size_of(ty);
 791
 792                 // This is the same sequence that Clang emits for pointer subtraction.
 793                 // It can be neither `nsw` nor `nuw` because the input is treated as
 794                 // unsigned but then the output is treated as signed, so neither works.
 795                 let a = args[0].immediate();
 796                 let b = args[1].immediate();
 797                 let a = self.ptrtoint(a, self.type_isize());
 798                 let b = self.ptrtoint(b, self.type_isize());
 799                 let d = self.sub(a, b);
 800                 let pointee_size = self.const_usize(pointee_size.bytes());
 801                 // this is where the signed magic happens (notice the `s` in `exactsdiv`)
 802                 self.exactsdiv(d, pointee_size)
 803             }
 804
 805             _ => bug!("unknown intrinsic '{}'", name),
 806         };
 807
 808         if !fn_abi.ret.is_ignore() {
 809             if let PassMode::Cast(ty) = fn_abi.ret.mode {
 810                 let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
 811                 let ptr = self.pointercast(result.llval, ptr_llty);
 812                 self.store(llval, ptr, result.align);
 813             } else {
 814                 OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
 815                     .val
 816                     .store(self, result);
 817             }
 818         }
 819     }
 820
 821     fn abort(&mut self) {
 822         let fnname = self.get_intrinsic(&("llvm.trap"));
 823         self.call(fnname, &[], None);
 824     }
 825
 826     fn assume(&mut self, val: Self::Value) {
 827         let assume_intrinsic = self.get_intrinsic("llvm.assume");
 828         self.call(assume_intrinsic, &[val], None);
 829     }
 830
 831     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value {
 832         let expect = self.get_intrinsic(&"llvm.expect.i1");
 833         self.call(expect, &[cond, self.const_bool(expected)], None)
 834     }
 835
 836     fn sideeffect(&mut self) {
 837         if self.tcx.sess.opts.debugging_opts.insert_sideeffect {
 838             let fnname = self.get_intrinsic(&("llvm.sideeffect"));
 839             self.call(fnname, &[], None);
 840         }
 841     }
 842
 843     fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {
 844         let intrinsic = self.cx().get_intrinsic("llvm.va_start");
 845         self.call(intrinsic, &[va_list], None)
 846     }
 847
 848     fn va_end(&mut self, va_list: &'ll Value) -> &'ll Value {
 849         let intrinsic = self.cx().get_intrinsic("llvm.va_end");
 850         self.call(intrinsic, &[va_list], None)
 851     }
 852 }
 853
 854 fn copy_intrinsic(
 855     bx: &mut Builder<'a, 'll, 'tcx>,
 856     allow_overlap: bool,
 857     volatile: bool,
 858     ty: Ty<'tcx>,
 859     dst: &'ll Value,
 860     src: &'ll Value,
 861     count: &'ll Value,
 862 ) {
 863     let (size, align) = bx.size_and_align_of(ty);
 864     let size = bx.mul(bx.const_usize(size.bytes()), count);
 865     let flags = if volatile { MemFlags::VOLATILE } else { MemFlags::empty() };
 866     if allow_overlap {
 867         bx.memmove(dst, align, src, align, size, flags);
 868     } else {
 869         bx.memcpy(dst, align, src, align, size, flags);
 870     }
 871 }
 872
 873 fn memset_intrinsic(
 874     bx: &mut Builder<'a, 'll, 'tcx>,
 875     volatile: bool,
 876     ty: Ty<'tcx>,
 877     dst: &'ll Value,
 878     val: &'ll Value,
 879     count: &'ll Value,
 880 ) {
 881     let (size, align) = bx.size_and_align_of(ty);
 882     let size = bx.mul(bx.const_usize(size.bytes()), count);
 883     let flags = if volatile { MemFlags::VOLATILE } else { MemFlags::empty() };
 884     bx.memset(dst, val, size, align, flags);
 885 }
 886
 887 fn try_intrinsic(
 888     bx: &mut Builder<'a, 'll, 'tcx>,
 889     try_func: &'ll Value,
 890     data: &'ll Value,
 891     catch_func: &'ll Value,
 892     dest: &'ll Value,
 893 ) {
 894     if bx.sess().panic_strategy() == PanicStrategy::Abort {
 895         bx.call(try_func, &[data], None);
 896         // Return 0 unconditionally from the intrinsic call;
 897         // we can never unwind.
 898         let ret_align = bx.tcx().data_layout.i32_align.abi;
 899         bx.store(bx.const_i32(0), dest, ret_align);
 900     } else if wants_msvc_seh(bx.sess()) {
 901         codegen_msvc_try(bx, try_func, data, catch_func, dest);
 902     } else {
 903         codegen_gnu_try(bx, try_func, data, catch_func, dest);
 904     }
 905 }
 906
 907 // MSVC's definition of the `rust_try` function.
 908 //
 909 // This implementation uses the new exception handling instructions in LLVM
 910 // which have support in LLVM for SEH on MSVC targets. Although these
 911 // instructions are meant to work for all targets, as of the time of this
 912 // writing, however, LLVM does not recommend the usage of these new instructions
 913 // as the old ones are still more optimized.
 914 fn codegen_msvc_try(
 915     bx: &mut Builder<'a, 'll, 'tcx>,
 916     try_func: &'ll Value,
 917     data: &'ll Value,
 918     catch_func: &'ll Value,
 919     dest: &'ll Value,
 920 ) {
 921     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
 922         bx.set_personality_fn(bx.eh_personality());
 923         bx.sideeffect();
 924
 925         let mut normal = bx.build_sibling_block("normal");
 926         let mut catchswitch = bx.build_sibling_block("catchswitch");
 927         let mut catchpad = bx.build_sibling_block("catchpad");
 928         let mut caught = bx.build_sibling_block("caught");
 929
 930         let try_func = llvm::get_param(bx.llfn(), 0);
 931         let data = llvm::get_param(bx.llfn(), 1);
 932         let catch_func = llvm::get_param(bx.llfn(), 2);
 933
 934         // We're generating an IR snippet that looks like:
 935         //
 936         //   declare i32 @rust_try(%try_func, %data, %catch_func) {
 937         //      %slot = alloca u8*
 938         //      invoke %try_func(%data) to label %normal unwind label %catchswitch
 939         //
 940         //   normal:
 941         //      ret i32 0
 942         //
 943         //   catchswitch:
 944         //      %cs = catchswitch within none [%catchpad] unwind to caller
 945         //
 946         //   catchpad:
 947         //      %tok = catchpad within %cs [%type_descriptor, 0, %slot]
 948         //      %ptr = load %slot
 949         //      call %catch_func(%data, %ptr)
 950         //      catchret from %tok to label %caught
 951         //
 952         //   caught:
 953         //      ret i32 1
 954         //   }
 955         //
 956         // This structure follows the basic usage of throw/try/catch in LLVM.
 957         // For example, compile this C++ snippet to see what LLVM generates:
 958         //
 959         //      #include <stdint.h>
 960         //
 961         //      struct rust_panic {
 962         //          rust_panic(const rust_panic&);
 963         //          ~rust_panic();
 964         //
 965         //          uint64_t x[2];
 966         //      };
 967         //
 968         //      int __rust_try(
 969         //          void (*try_func)(void*),
 970         //          void *data,
 971         //          void (*catch_func)(void*, void*) noexcept
 972         //      ) {
 973         //          try {
 974         //              try_func(data);
 975         //              return 0;
 976         //          } catch(rust_panic& a) {
 977         //              catch_func(data, &a);
 978         //              return 1;
 979         //          }
 980         //      }
 981         //
 982         // More information can be found in libstd's seh.rs implementation.
 983         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 984         let slot = bx.alloca(bx.type_i8p(), ptr_align);
 985         bx.invoke(try_func, &[data], normal.llbb(), catchswitch.llbb(), None);
 986
 987         normal.ret(bx.const_i32(0));
 988
 989         let cs = catchswitch.catch_switch(None, None, 1);
 990         catchswitch.add_handler(cs, catchpad.llbb());
 991
 992         // We can't use the TypeDescriptor defined in libpanic_unwind because it
 993         // might be in another DLL and the SEH encoding only supports specifying
 994         // a TypeDescriptor from the current module.
 995         //
 996         // However this isn't an issue since the MSVC runtime uses string
 997         // comparison on the type name to match TypeDescriptors rather than
 998         // pointer equality.
 999         //
1000         // So instead we generate a new TypeDescriptor in each module that uses
1001         // `try` and let the linker merge duplicate definitions in the same
1002         // module.
1003         //
1004         // When modifying, make sure that the type_name string exactly matches
1005         // the one used in src/libpanic_unwind/seh.rs.
1006         let type_info_vtable = bx.declare_global("??_7type_info@@6B@", bx.type_i8p());
1007         let type_name = bx.const_bytes(b"rust_panic\0");
1008         let type_info =
1009             bx.const_struct(&[type_info_vtable, bx.const_null(bx.type_i8p()), type_name], false);
1010         let tydesc = bx.declare_global("__rust_panic_type_info", bx.val_ty(type_info));
1011         unsafe {
1012             llvm::LLVMRustSetLinkage(tydesc, llvm::Linkage::LinkOnceODRLinkage);
1013             llvm::SetUniqueComdat(bx.llmod, tydesc);
1014             llvm::LLVMSetInitializer(tydesc, type_info);
1015         }
1016
1017         // The flag value of 8 indicates that we are catching the exception by
1018         // reference instead of by value. We can't use catch by value because
1019         // that requires copying the exception object, which we don't support
1020         // since our exception object effectively contains a Box.
1021         //
1022         // Source: MicrosoftCXXABI::getAddrOfCXXCatchHandlerType in clang
1023         let flags = bx.const_i32(8);
1024         let funclet = catchpad.catch_pad(cs, &[tydesc, flags, slot]);
1025         let ptr = catchpad.load(slot, ptr_align);
1026         catchpad.call(catch_func, &[data, ptr], Some(&funclet));
1027
1028         catchpad.catch_ret(&funclet, caught.llbb());
1029
1030         caught.ret(bx.const_i32(1));
1031     });
1032
1033     // Note that no invoke is used here because by definition this function
1034     // can't panic (that's what it's catching).
1035     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
1036     let i32_align = bx.tcx().data_layout.i32_align.abi;
1037     bx.store(ret, dest, i32_align);
1038 }
1039
1040 // Definition of the standard `try` function for Rust using the GNU-like model
1041 // of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
1042 // instructions).
1043 //
1044 // This codegen is a little surprising because we always call a shim
1045 // function instead of inlining the call to `invoke` manually here. This is done
1046 // because in LLVM we're only allowed to have one personality per function
1047 // definition. The call to the `try` intrinsic is being inlined into the
1048 // function calling it, and that function may already have other personality
1049 // functions in play. By calling a shim we're guaranteed that our shim will have
1050 // the right personality function.
1051 fn codegen_gnu_try(
1052     bx: &mut Builder<'a, 'll, 'tcx>,
1053     try_func: &'ll Value,
1054     data: &'ll Value,
1055     catch_func: &'ll Value,
1056     dest: &'ll Value,
1057 ) {
1058     let llfn = get_rust_try_fn(bx, &mut |mut bx| {
1059         // Codegens the shims described above:
1060         //
1061         //   bx:
1062         //      invoke %try_func(%data) normal %normal unwind %catch
1063         //
1064         //   normal:
1065         //      ret 0
1066         //
1067         //   catch:
1068         //      (%ptr, _) = landingpad
1069         //      call %catch_func(%data, %ptr)
1070         //      ret 1
1071
1072         bx.sideeffect();
1073
1074         let mut then = bx.build_sibling_block("then");
1075         let mut catch = bx.build_sibling_block("catch");
1076
1077         let try_func = llvm::get_param(bx.llfn(), 0);
1078         let data = llvm::get_param(bx.llfn(), 1);
1079         let catch_func = llvm::get_param(bx.llfn(), 2);
1080         bx.invoke(try_func, &[data], then.llbb(), catch.llbb(), None);
1081         then.ret(bx.const_i32(0));
1082
1083         // Type indicator for the exception being thrown.
1084         //
1085         // The first value in this tuple is a pointer to the exception object
1086         // being thrown.  The second value is a "selector" indicating which of
1087         // the landing pad clauses the exception's type had been matched to.
1088         // rust_try ignores the selector.
1089         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
1090         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 1);
1091         let tydesc = match bx.tcx().lang_items().eh_catch_typeinfo() {
1092             Some(tydesc) => {
1093                 let tydesc = bx.get_static(tydesc);
1094                 bx.bitcast(tydesc, bx.type_i8p())
1095             }
1096             None => bx.const_null(bx.type_i8p()),
1097         };
1098         catch.add_clause(vals, tydesc);
1099         let ptr = catch.extract_value(vals, 0);
1100         catch.call(catch_func, &[data, ptr], None);
1101         catch.ret(bx.const_i32(1));
1102     });
1103
1104     // Note that no invoke is used here because by definition this function
1105     // can't panic (that's what it's catching).
1106     let ret = bx.call(llfn, &[try_func, data, catch_func], None);
1107     let i32_align = bx.tcx().data_layout.i32_align.abi;
1108     bx.store(ret, dest, i32_align);
1109 }
1110
1111 // Helper function to give a Block to a closure to codegen a shim function.
1112 // This is currently primarily used for the `try` intrinsic functions above.
1113 fn gen_fn<'ll, 'tcx>(
1114     cx: &CodegenCx<'ll, 'tcx>,
1115     name: &str,
1116     inputs: Vec<Ty<'tcx>>,
1117     output: Ty<'tcx>,
1118     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1119 ) -> &'ll Value {
1120     let rust_fn_sig = ty::Binder::bind(cx.tcx.mk_fn_sig(
1121         inputs.into_iter(),
1122         output,
1123         false,
1124         hir::Unsafety::Unsafe,
1125         Abi::Rust,
1126     ));
1127     let fn_abi = FnAbi::of_fn_ptr(cx, rust_fn_sig, &[]);
1128     let llfn = cx.declare_fn(name, &fn_abi);
1129     cx.set_frame_pointer_elimination(llfn);
1130     cx.apply_target_cpu_attr(llfn);
1131     // FIXME(eddyb) find a nicer way to do this.
1132     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
1133     let bx = Builder::new_block(cx, llfn, "entry-block");
1134     codegen(bx);
1135     llfn
1136 }
1137
1138 // Helper function used to get a handle to the `__rust_try` function used to
1139 // catch exceptions.
1140 //
1141 // This function is only generated once and is then cached.
1142 fn get_rust_try_fn<'ll, 'tcx>(
1143     cx: &CodegenCx<'ll, 'tcx>,
1144     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
1145 ) -> &'ll Value {
1146     if let Some(llfn) = cx.rust_try_fn.get() {
1147         return llfn;
1148     }
1149
1150     // Define the type up front for the signature of the rust_try function.
1151     let tcx = cx.tcx;
1152     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
1153     let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
1154         iter::once(i8p),
1155         tcx.mk_unit(),
1156         false,
1157         hir::Unsafety::Unsafe,
1158         Abi::Rust,
1159     )));
1160     let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::bind(tcx.mk_fn_sig(
1161         [i8p, i8p].iter().cloned(),
1162         tcx.mk_unit(),
1163         false,
1164         hir::Unsafety::Unsafe,
1165         Abi::Rust,
1166     )));
1167     let output = tcx.types.i32;
1168     let rust_try = gen_fn(cx, "__rust_try", vec![try_fn_ty, i8p, catch_fn_ty], output, codegen);
1169     cx.rust_try_fn.set(Some(rust_try));
1170     rust_try
1171 }
1172
1173 fn generic_simd_intrinsic(
1174     bx: &mut Builder<'a, 'll, 'tcx>,
1175     name: &str,
1176     callee_ty: Ty<'tcx>,
1177     args: &[OperandRef<'tcx, &'ll Value>],
1178     ret_ty: Ty<'tcx>,
1179     llret_ty: &'ll Type,
1180     span: Span,
1181 ) -> Result<&'ll Value, ()> {
1182     // macros for error handling:
1183     macro_rules! emit_error {
1184         ($msg: tt) => {
1185             emit_error!($msg, )
1186         };
1187         ($msg: tt, $($fmt: tt)*) => {
1188             span_invalid_monomorphization_error(
1189                 bx.sess(), span,
1190                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1191                          name, $($fmt)*));
1192         }
1193     }
1194
1195     macro_rules! return_error {
1196         ($($fmt: tt)*) => {
1197             {
1198                 emit_error!($($fmt)*);
1199                 return Err(());
1200             }
1201         }
1202     }
1203
1204     macro_rules! require {
1205         ($cond: expr, $($fmt: tt)*) => {
1206             if !$cond {
1207                 return_error!($($fmt)*);
1208             }
1209         };
1210     }
1211
1212     macro_rules! require_simd {
1213         ($ty: expr, $position: expr) => {
1214             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
1215         };
1216     }
1217
1218     let tcx = bx.tcx();
1219     let sig = tcx
1220         .normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), &callee_ty.fn_sig(tcx));
1221     let arg_tys = sig.inputs();
1222
1223     if name == "simd_select_bitmask" {
1224         let in_ty = arg_tys[0];
1225         let m_len = match in_ty.kind {
1226             // Note that this `.unwrap()` crashes for isize/usize, that's sort
1227             // of intentional as there's not currently a use case for that.
1228             ty::Int(i) => i.bit_width().unwrap(),
1229             ty::Uint(i) => i.bit_width().unwrap(),
1230             _ => return_error!("`{}` is not an integral type", in_ty),
1231         };
1232         require_simd!(arg_tys[1], "argument");
1233         let v_len = arg_tys[1].simd_size(tcx);
1234         require!(
1235             m_len == v_len,
1236             "mismatched lengths: mask length `{}` != other vector length `{}`",
1237             m_len,
1238             v_len
1239         );
1240         let i1 = bx.type_i1();
1241         let i1xn = bx.type_vector(i1, m_len);
1242         let m_i1s = bx.bitcast(args[0].immediate(), i1xn);
1243         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1244     }
1245
1246     // every intrinsic below takes a SIMD vector as its first argument
1247     require_simd!(arg_tys[0], "input");
1248     let in_ty = arg_tys[0];
1249     let in_elem = arg_tys[0].simd_type(tcx);
1250     let in_len = arg_tys[0].simd_size(tcx);
1251
1252     let comparison = match name {
1253         "simd_eq" => Some(hir::BinOpKind::Eq),
1254         "simd_ne" => Some(hir::BinOpKind::Ne),
1255         "simd_lt" => Some(hir::BinOpKind::Lt),
1256         "simd_le" => Some(hir::BinOpKind::Le),
1257         "simd_gt" => Some(hir::BinOpKind::Gt),
1258         "simd_ge" => Some(hir::BinOpKind::Ge),
1259         _ => None,
1260     };
1261
1262     if let Some(cmp_op) = comparison {
1263         require_simd!(ret_ty, "return");
1264
1265         let out_len = ret_ty.simd_size(tcx);
1266         require!(
1267             in_len == out_len,
1268             "expected return type with length {} (same as input type `{}`), \
1269                   found `{}` with length {}",
1270             in_len,
1271             in_ty,
1272             ret_ty,
1273             out_len
1274         );
1275         require!(
1276             bx.type_kind(bx.element_type(llret_ty)) == TypeKind::Integer,
1277             "expected return type with integer elements, found `{}` with non-integer `{}`",
1278             ret_ty,
1279             ret_ty.simd_type(tcx)
1280         );
1281
1282         return Ok(compare_simd_types(
1283             bx,
1284             args[0].immediate(),
1285             args[1].immediate(),
1286             in_elem,
1287             llret_ty,
1288             cmp_op,
1289         ));
1290     }
1291
1292     if name.starts_with("simd_shuffle") {
1293         let n: u64 = name["simd_shuffle".len()..].parse().unwrap_or_else(|_| {
1294             span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
1295         });
1296
1297         require_simd!(ret_ty, "return");
1298
1299         let out_len = ret_ty.simd_size(tcx);
1300         require!(
1301             out_len == n,
1302             "expected return type of length {}, found `{}` with length {}",
1303             n,
1304             ret_ty,
1305             out_len
1306         );
1307         require!(
1308             in_elem == ret_ty.simd_type(tcx),
1309             "expected return element type `{}` (element of input `{}`), \
1310                   found `{}` with element type `{}`",
1311             in_elem,
1312             in_ty,
1313             ret_ty,
1314             ret_ty.simd_type(tcx)
1315         );
1316
1317         let total_len = u128::from(in_len) * 2;
1318
1319         let vector = args[2].immediate();
1320
1321         let indices: Option<Vec<_>> = (0..n)
1322             .map(|i| {
1323                 let arg_idx = i;
1324                 let val = bx.const_get_elt(vector, i as u64);
1325                 match bx.const_to_opt_u128(val, true) {
1326                     None => {
1327                         emit_error!("shuffle index #{} is not a constant", arg_idx);
1328                         None
1329                     }
1330                     Some(idx) if idx >= total_len => {
1331                         emit_error!(
1332                             "shuffle index #{} is out of bounds (limit {})",
1333                             arg_idx,
1334                             total_len
1335                         );
1336                         None
1337                     }
1338                     Some(idx) => Some(bx.const_i32(idx as i32)),
1339                 }
1340             })
1341             .collect();
1342         let indices = match indices {
1343             Some(i) => i,
1344             None => return Ok(bx.const_null(llret_ty)),
1345         };
1346
1347         return Ok(bx.shuffle_vector(
1348             args[0].immediate(),
1349             args[1].immediate(),
1350             bx.const_vector(&indices),
1351         ));
1352     }
1353
1354     if name == "simd_insert" {
1355         require!(
1356             in_elem == arg_tys[2],
1357             "expected inserted type `{}` (element of input `{}`), found `{}`",
1358             in_elem,
1359             in_ty,
1360             arg_tys[2]
1361         );
1362         return Ok(bx.insert_element(
1363             args[0].immediate(),
1364             args[2].immediate(),
1365             args[1].immediate(),
1366         ));
1367     }
1368     if name == "simd_extract" {
1369         require!(
1370             ret_ty == in_elem,
1371             "expected return type `{}` (element of input `{}`), found `{}`",
1372             in_elem,
1373             in_ty,
1374             ret_ty
1375         );
1376         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()));
1377     }
1378
1379     if name == "simd_select" {
1380         let m_elem_ty = in_elem;
1381         let m_len = in_len;
1382         require_simd!(arg_tys[1], "argument");
1383         let v_len = arg_tys[1].simd_size(tcx);
1384         require!(
1385             m_len == v_len,
1386             "mismatched lengths: mask length `{}` != other vector length `{}`",
1387             m_len,
1388             v_len
1389         );
1390         match m_elem_ty.kind {
1391             ty::Int(_) => {}
1392             _ => return_error!("mask element type is `{}`, expected `i_`", m_elem_ty),
1393         }
1394         // truncate the mask to a vector of i1s
1395         let i1 = bx.type_i1();
1396         let i1xn = bx.type_vector(i1, m_len as u64);
1397         let m_i1s = bx.trunc(args[0].immediate(), i1xn);
1398         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1399     }
1400
1401     if name == "simd_bitmask" {
1402         // The `fn simd_bitmask(vector) -> unsigned integer` intrinsic takes a
1403         // vector mask and returns an unsigned integer containing the most
1404         // significant bit (MSB) of each lane.
1405
1406         // If the vector has less than 8 lanes, an u8 is returned with zeroed
1407         // trailing bits.
1408         let expected_int_bits = in_len.max(8);
1409         match ret_ty.kind {
1410             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => (),
1411             _ => return_error!("bitmask `{}`, expected `u{}`", ret_ty, expected_int_bits),
1412         }
1413
1414         // Integer vector <i{in_bitwidth} x in_len>:
1415         let (i_xn, in_elem_bitwidth) = match in_elem.kind {
1416             ty::Int(i) => {
1417                 (args[0].immediate(), i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits()))
1418             }
1419             ty::Uint(i) => {
1420                 (args[0].immediate(), i.bit_width().unwrap_or(bx.data_layout().pointer_size.bits()))
1421             }
1422             _ => return_error!(
1423                 "vector argument `{}`'s element type `{}`, expected integer element type",
1424                 in_ty,
1425                 in_elem
1426             ),
1427         };
1428
1429         // Shift the MSB to the right by "in_elem_bitwidth - 1" into the first bit position.
1430         let shift_indices =
1431             vec![
1432                 bx.cx.const_int(bx.type_ix(in_elem_bitwidth), (in_elem_bitwidth - 1) as _);
1433                 in_len as _
1434             ];
1435         let i_xn_msb = bx.lshr(i_xn, bx.const_vector(shift_indices.as_slice()));
1436         // Truncate vector to an <i1 x N>
1437         let i1xn = bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len));
1438         // Bitcast <i1 x N> to iN:
1439         let i_ = bx.bitcast(i1xn, bx.type_ix(in_len));
1440         // Zero-extend iN to the bitmask type:
1441         return Ok(bx.zext(i_, bx.type_ix(expected_int_bits)));
1442     }
1443
1444     fn simd_simple_float_intrinsic(
1445         name: &str,
1446         in_elem: &::rustc_middle::ty::TyS<'_>,
1447         in_ty: &::rustc_middle::ty::TyS<'_>,
1448         in_len: u64,
1449         bx: &mut Builder<'a, 'll, 'tcx>,
1450         span: Span,
1451         args: &[OperandRef<'tcx, &'ll Value>],
1452     ) -> Result<&'ll Value, ()> {
1453         macro_rules! emit_error {
1454             ($msg: tt) => {
1455                 emit_error!($msg, )
1456             };
1457             ($msg: tt, $($fmt: tt)*) => {
1458                 span_invalid_monomorphization_error(
1459                     bx.sess(), span,
1460                     &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1461                              name, $($fmt)*));
1462             }
1463         }
1464         macro_rules! return_error {
1465             ($($fmt: tt)*) => {
1466                 {
1467                     emit_error!($($fmt)*);
1468                     return Err(());
1469                 }
1470             }
1471         }
1472         let ety = match in_elem.kind {
1473             ty::Float(f) if f.bit_width() == 32 => {
1474                 if in_len < 2 || in_len > 16 {
1475                     return_error!(
1476                         "unsupported floating-point vector `{}` with length `{}` \
1477                          out-of-range [2, 16]",
1478                         in_ty,
1479                         in_len
1480                     );
1481                 }
1482                 "f32"
1483             }
1484             ty::Float(f) if f.bit_width() == 64 => {
1485                 if in_len < 2 || in_len > 8 {
1486                     return_error!(
1487                         "unsupported floating-point vector `{}` with length `{}` \
1488                                    out-of-range [2, 8]",
1489                         in_ty,
1490                         in_len
1491                     );
1492                 }
1493                 "f64"
1494             }
1495             ty::Float(f) => {
1496                 return_error!(
1497                     "unsupported element type `{}` of floating-point vector `{}`",
1498                     f.name_str(),
1499                     in_ty
1500                 );
1501             }
1502             _ => {
1503                 return_error!("`{}` is not a floating-point type", in_ty);
1504             }
1505         };
1506
1507         let llvm_name = &format!("llvm.{0}.v{1}{2}", name, in_len, ety);
1508         let intrinsic = bx.get_intrinsic(&llvm_name);
1509         let c =
1510             bx.call(intrinsic, &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(), None);
1511         unsafe { llvm::LLVMRustSetHasUnsafeAlgebra(c) };
1512         Ok(c)
1513     }
1514
1515     match name {
1516         "simd_fsqrt" => {
1517             return simd_simple_float_intrinsic("sqrt", in_elem, in_ty, in_len, bx, span, args);
1518         }
1519         "simd_fsin" => {
1520             return simd_simple_float_intrinsic("sin", in_elem, in_ty, in_len, bx, span, args);
1521         }
1522         "simd_fcos" => {
1523             return simd_simple_float_intrinsic("cos", in_elem, in_ty, in_len, bx, span, args);
1524         }
1525         "simd_fabs" => {
1526             return simd_simple_float_intrinsic("fabs", in_elem, in_ty, in_len, bx, span, args);
1527         }
1528         "simd_floor" => {
1529             return simd_simple_float_intrinsic("floor", in_elem, in_ty, in_len, bx, span, args);
1530         }
1531         "simd_ceil" => {
1532             return simd_simple_float_intrinsic("ceil", in_elem, in_ty, in_len, bx, span, args);
1533         }
1534         "simd_fexp" => {
1535             return simd_simple_float_intrinsic("exp", in_elem, in_ty, in_len, bx, span, args);
1536         }
1537         "simd_fexp2" => {
1538             return simd_simple_float_intrinsic("exp2", in_elem, in_ty, in_len, bx, span, args);
1539         }
1540         "simd_flog10" => {
1541             return simd_simple_float_intrinsic("log10", in_elem, in_ty, in_len, bx, span, args);
1542         }
1543         "simd_flog2" => {
1544             return simd_simple_float_intrinsic("log2", in_elem, in_ty, in_len, bx, span, args);
1545         }
1546         "simd_flog" => {
1547             return simd_simple_float_intrinsic("log", in_elem, in_ty, in_len, bx, span, args);
1548         }
1549         "simd_fpowi" => {
1550             return simd_simple_float_intrinsic("powi", in_elem, in_ty, in_len, bx, span, args);
1551         }
1552         "simd_fpow" => {
1553             return simd_simple_float_intrinsic("pow", in_elem, in_ty, in_len, bx, span, args);
1554         }
1555         "simd_fma" => {
1556             return simd_simple_float_intrinsic("fma", in_elem, in_ty, in_len, bx, span, args);
1557         }
1558         _ => { /* fallthrough */ }
1559     }
1560
1561     // FIXME: use:
1562     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Function.h#L182
1563     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Intrinsics.h#L81
1564     fn llvm_vector_str(elem_ty: Ty<'_>, vec_len: u64, no_pointers: usize) -> String {
1565         let p0s: String = "p0".repeat(no_pointers);
1566         match elem_ty.kind {
1567             ty::Int(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1568             ty::Uint(v) => format!("v{}{}i{}", vec_len, p0s, v.bit_width().unwrap()),
1569             ty::Float(v) => format!("v{}{}f{}", vec_len, p0s, v.bit_width()),
1570             _ => unreachable!(),
1571         }
1572     }
1573
1574     fn llvm_vector_ty(
1575         cx: &CodegenCx<'ll, '_>,
1576         elem_ty: Ty<'_>,
1577         vec_len: u64,
1578         mut no_pointers: usize,
1579     ) -> &'ll Type {
1580         // FIXME: use cx.layout_of(ty).llvm_type() ?
1581         let mut elem_ty = match elem_ty.kind {
1582             ty::Int(v) => cx.type_int_from_ty(v),
1583             ty::Uint(v) => cx.type_uint_from_ty(v),
1584             ty::Float(v) => cx.type_float_from_ty(v),
1585             _ => unreachable!(),
1586         };
1587         while no_pointers > 0 {
1588             elem_ty = cx.type_ptr_to(elem_ty);
1589             no_pointers -= 1;
1590         }
1591         cx.type_vector(elem_ty, vec_len)
1592     }
1593
1594     if name == "simd_gather" {
1595         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
1596         //             mask: <N x i{M}>) -> <N x T>
1597         // * N: number of elements in the input vectors
1598         // * T: type of the element to load
1599         // * M: any integer width is supported, will be truncated to i1
1600
1601         // All types must be simd vector types
1602         require_simd!(in_ty, "first");
1603         require_simd!(arg_tys[1], "second");
1604         require_simd!(arg_tys[2], "third");
1605         require_simd!(ret_ty, "return");
1606
1607         // Of the same length:
1608         require!(
1609             in_len == arg_tys[1].simd_size(tcx),
1610             "expected {} argument with length {} (same as input type `{}`), \
1611                   found `{}` with length {}",
1612             "second",
1613             in_len,
1614             in_ty,
1615             arg_tys[1],
1616             arg_tys[1].simd_size(tcx)
1617         );
1618         require!(
1619             in_len == arg_tys[2].simd_size(tcx),
1620             "expected {} argument with length {} (same as input type `{}`), \
1621                   found `{}` with length {}",
1622             "third",
1623             in_len,
1624             in_ty,
1625             arg_tys[2],
1626             arg_tys[2].simd_size(tcx)
1627         );
1628
1629         // The return type must match the first argument type
1630         require!(ret_ty == in_ty, "expected return type `{}`, found `{}`", in_ty, ret_ty);
1631
1632         // This counts how many pointers
1633         fn ptr_count(t: Ty<'_>) -> usize {
1634             match t.kind {
1635                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1636                 _ => 0,
1637             }
1638         }
1639
1640         // Non-ptr type
1641         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1642             match t.kind {
1643                 ty::RawPtr(p) => non_ptr(p.ty),
1644                 _ => t,
1645             }
1646         }
1647
1648         // The second argument must be a simd vector with an element type that's a pointer
1649         // to the element type of the first argument
1650         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).kind {
1651             ty::RawPtr(p) if p.ty == in_elem => {
1652                 (ptr_count(arg_tys[1].simd_type(tcx)), non_ptr(arg_tys[1].simd_type(tcx)))
1653             }
1654             _ => {
1655                 require!(
1656                     false,
1657                     "expected element type `{}` of second argument `{}` \
1658                                  to be a pointer to the element type `{}` of the first \
1659                                  argument `{}`, found `{}` != `*_ {}`",
1660                     arg_tys[1].simd_type(tcx),
1661                     arg_tys[1],
1662                     in_elem,
1663                     in_ty,
1664                     arg_tys[1].simd_type(tcx),
1665                     in_elem
1666                 );
1667                 unreachable!();
1668             }
1669         };
1670         assert!(pointer_count > 0);
1671         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1672         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1673
1674         // The element type of the third argument must be a signed integer type of any width:
1675         match arg_tys[2].simd_type(tcx).kind {
1676             ty::Int(_) => (),
1677             _ => {
1678                 require!(
1679                     false,
1680                     "expected element type `{}` of third argument `{}` \
1681                                  to be a signed integer type",
1682                     arg_tys[2].simd_type(tcx),
1683                     arg_tys[2]
1684                 );
1685             }
1686         }
1687
1688         // Alignment of T, must be a constant integer value:
1689         let alignment_ty = bx.type_i32();
1690         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1691
1692         // Truncate the mask vector to a vector of i1s:
1693         let (mask, mask_ty) = {
1694             let i1 = bx.type_i1();
1695             let i1xn = bx.type_vector(i1, in_len);
1696             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1697         };
1698
1699         // Type of the vector of pointers:
1700         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1701         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1702
1703         // Type of the vector of elements:
1704         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1705         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1706
1707         let llvm_intrinsic =
1708             format!("llvm.masked.gather.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1709         let f = bx.declare_cfn(
1710             &llvm_intrinsic,
1711             bx.type_func(
1712                 &[llvm_pointer_vec_ty, alignment_ty, mask_ty, llvm_elem_vec_ty],
1713                 llvm_elem_vec_ty,
1714             ),
1715         );
1716         llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
1717         let v = bx.call(f, &[args[1].immediate(), alignment, mask, args[0].immediate()], None);
1718         return Ok(v);
1719     }
1720
1721     if name == "simd_scatter" {
1722         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
1723         //             mask: <N x i{M}>) -> ()
1724         // * N: number of elements in the input vectors
1725         // * T: type of the element to load
1726         // * M: any integer width is supported, will be truncated to i1
1727
1728         // All types must be simd vector types
1729         require_simd!(in_ty, "first");
1730         require_simd!(arg_tys[1], "second");
1731         require_simd!(arg_tys[2], "third");
1732
1733         // Of the same length:
1734         require!(
1735             in_len == arg_tys[1].simd_size(tcx),
1736             "expected {} argument with length {} (same as input type `{}`), \
1737                   found `{}` with length {}",
1738             "second",
1739             in_len,
1740             in_ty,
1741             arg_tys[1],
1742             arg_tys[1].simd_size(tcx)
1743         );
1744         require!(
1745             in_len == arg_tys[2].simd_size(tcx),
1746             "expected {} argument with length {} (same as input type `{}`), \
1747                   found `{}` with length {}",
1748             "third",
1749             in_len,
1750             in_ty,
1751             arg_tys[2],
1752             arg_tys[2].simd_size(tcx)
1753         );
1754
1755         // This counts how many pointers
1756         fn ptr_count(t: Ty<'_>) -> usize {
1757             match t.kind {
1758                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1759                 _ => 0,
1760             }
1761         }
1762
1763         // Non-ptr type
1764         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1765             match t.kind {
1766                 ty::RawPtr(p) => non_ptr(p.ty),
1767                 _ => t,
1768             }
1769         }
1770
1771         // The second argument must be a simd vector with an element type that's a pointer
1772         // to the element type of the first argument
1773         let (pointer_count, underlying_ty) = match arg_tys[1].simd_type(tcx).kind {
1774             ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::Mutability::Mut => {
1775                 (ptr_count(arg_tys[1].simd_type(tcx)), non_ptr(arg_tys[1].simd_type(tcx)))
1776             }
1777             _ => {
1778                 require!(
1779                     false,
1780                     "expected element type `{}` of second argument `{}` \
1781                                  to be a pointer to the element type `{}` of the first \
1782                                  argument `{}`, found `{}` != `*mut {}`",
1783                     arg_tys[1].simd_type(tcx),
1784                     arg_tys[1],
1785                     in_elem,
1786                     in_ty,
1787                     arg_tys[1].simd_type(tcx),
1788                     in_elem
1789                 );
1790                 unreachable!();
1791             }
1792         };
1793         assert!(pointer_count > 0);
1794         assert_eq!(pointer_count - 1, ptr_count(arg_tys[0].simd_type(tcx)));
1795         assert_eq!(underlying_ty, non_ptr(arg_tys[0].simd_type(tcx)));
1796
1797         // The element type of the third argument must be a signed integer type of any width:
1798         match arg_tys[2].simd_type(tcx).kind {
1799             ty::Int(_) => (),
1800             _ => {
1801                 require!(
1802                     false,
1803                     "expected element type `{}` of third argument `{}` \
1804                                  to be a signed integer type",
1805                     arg_tys[2].simd_type(tcx),
1806                     arg_tys[2]
1807                 );
1808             }
1809         }
1810
1811         // Alignment of T, must be a constant integer value:
1812         let alignment_ty = bx.type_i32();
1813         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1814
1815         // Truncate the mask vector to a vector of i1s:
1816         let (mask, mask_ty) = {
1817             let i1 = bx.type_i1();
1818             let i1xn = bx.type_vector(i1, in_len);
1819             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1820         };
1821
1822         let ret_t = bx.type_void();
1823
1824         // Type of the vector of pointers:
1825         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1826         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count);
1827
1828         // Type of the vector of elements:
1829         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1830         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1);
1831
1832         let llvm_intrinsic =
1833             format!("llvm.masked.scatter.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1834         let f = bx.declare_cfn(
1835             &llvm_intrinsic,
1836             bx.type_func(&[llvm_elem_vec_ty, llvm_pointer_vec_ty, alignment_ty, mask_ty], ret_t),
1837         );
1838         llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
1839         let v = bx.call(f, &[args[0].immediate(), args[1].immediate(), alignment, mask], None);
1840         return Ok(v);
1841     }
1842
1843     macro_rules! arith_red {
1844         ($name:tt : $integer_reduce:ident, $float_reduce:ident, $ordered:expr) => {
1845             if name == $name {
1846                 require!(
1847                     ret_ty == in_elem,
1848                     "expected return type `{}` (element of input `{}`), found `{}`",
1849                     in_elem,
1850                     in_ty,
1851                     ret_ty
1852                 );
1853                 return match in_elem.kind {
1854                     ty::Int(_) | ty::Uint(_) => {
1855                         let r = bx.$integer_reduce(args[0].immediate());
1856                         if $ordered {
1857                             // if overflow occurs, the result is the
1858                             // mathematical result modulo 2^n:
1859                             if name.contains("mul") {
1860                                 Ok(bx.mul(args[1].immediate(), r))
1861                             } else {
1862                                 Ok(bx.add(args[1].immediate(), r))
1863                             }
1864                         } else {
1865                             Ok(bx.$integer_reduce(args[0].immediate()))
1866                         }
1867                     }
1868                     ty::Float(f) => {
1869                         let acc = if $ordered {
1870                             // ordered arithmetic reductions take an accumulator
1871                             args[1].immediate()
1872                         } else {
1873                             // unordered arithmetic reductions use the identity accumulator
1874                             let identity_acc = if $name.contains("mul") { 1.0 } else { 0.0 };
1875                             match f.bit_width() {
1876                                 32 => bx.const_real(bx.type_f32(), identity_acc),
1877                                 64 => bx.const_real(bx.type_f64(), identity_acc),
1878                                 v => return_error!(
1879                                     r#"
1880 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
1881                                     $name,
1882                                     in_ty,
1883                                     in_elem,
1884                                     v,
1885                                     ret_ty
1886                                 ),
1887                             }
1888                         };
1889                         Ok(bx.$float_reduce(acc, args[0].immediate()))
1890                     }
1891                     _ => return_error!(
1892                         "unsupported {} from `{}` with element `{}` to `{}`",
1893                         $name,
1894                         in_ty,
1895                         in_elem,
1896                         ret_ty
1897                     ),
1898                 };
1899             }
1900         };
1901     }
1902
1903     arith_red!("simd_reduce_add_ordered": vector_reduce_add, vector_reduce_fadd, true);
1904     arith_red!("simd_reduce_mul_ordered": vector_reduce_mul, vector_reduce_fmul, true);
1905     arith_red!("simd_reduce_add_unordered": vector_reduce_add, vector_reduce_fadd_fast, false);
1906     arith_red!("simd_reduce_mul_unordered": vector_reduce_mul, vector_reduce_fmul_fast, false);
1907
1908     macro_rules! minmax_red {
1909         ($name:tt: $int_red:ident, $float_red:ident) => {
1910             if name == $name {
1911                 require!(
1912                     ret_ty == in_elem,
1913                     "expected return type `{}` (element of input `{}`), found `{}`",
1914                     in_elem,
1915                     in_ty,
1916                     ret_ty
1917                 );
1918                 return match in_elem.kind {
1919                     ty::Int(_i) => Ok(bx.$int_red(args[0].immediate(), true)),
1920                     ty::Uint(_u) => Ok(bx.$int_red(args[0].immediate(), false)),
1921                     ty::Float(_f) => Ok(bx.$float_red(args[0].immediate())),
1922                     _ => return_error!(
1923                         "unsupported {} from `{}` with element `{}` to `{}`",
1924                         $name,
1925                         in_ty,
1926                         in_elem,
1927                         ret_ty
1928                     ),
1929                 };
1930             }
1931         };
1932     }
1933
1934     minmax_red!("simd_reduce_min": vector_reduce_min, vector_reduce_fmin);
1935     minmax_red!("simd_reduce_max": vector_reduce_max, vector_reduce_fmax);
1936
1937     minmax_red!("simd_reduce_min_nanless": vector_reduce_min, vector_reduce_fmin_fast);
1938     minmax_red!("simd_reduce_max_nanless": vector_reduce_max, vector_reduce_fmax_fast);
1939
1940     macro_rules! bitwise_red {
1941         ($name:tt : $red:ident, $boolean:expr) => {
1942             if name == $name {
1943                 let input = if !$boolean {
1944                     require!(
1945                         ret_ty == in_elem,
1946                         "expected return type `{}` (element of input `{}`), found `{}`",
1947                         in_elem,
1948                         in_ty,
1949                         ret_ty
1950                     );
1951                     args[0].immediate()
1952                 } else {
1953                     match in_elem.kind {
1954                         ty::Int(_) | ty::Uint(_) => {}
1955                         _ => return_error!(
1956                             "unsupported {} from `{}` with element `{}` to `{}`",
1957                             $name,
1958                             in_ty,
1959                             in_elem,
1960                             ret_ty
1961                         ),
1962                     }
1963
1964                     // boolean reductions operate on vectors of i1s:
1965                     let i1 = bx.type_i1();
1966                     let i1xn = bx.type_vector(i1, in_len as u64);
1967                     bx.trunc(args[0].immediate(), i1xn)
1968                 };
1969                 return match in_elem.kind {
1970                     ty::Int(_) | ty::Uint(_) => {
1971                         let r = bx.$red(input);
1972                         Ok(if !$boolean { r } else { bx.zext(r, bx.type_bool()) })
1973                     }
1974                     _ => return_error!(
1975                         "unsupported {} from `{}` with element `{}` to `{}`",
1976                         $name,
1977                         in_ty,
1978                         in_elem,
1979                         ret_ty
1980                     ),
1981                 };
1982             }
1983         };
1984     }
1985
1986     bitwise_red!("simd_reduce_and": vector_reduce_and, false);
1987     bitwise_red!("simd_reduce_or": vector_reduce_or, false);
1988     bitwise_red!("simd_reduce_xor": vector_reduce_xor, false);
1989     bitwise_red!("simd_reduce_all": vector_reduce_and, true);
1990     bitwise_red!("simd_reduce_any": vector_reduce_or, true);
1991
1992     if name == "simd_cast" {
1993         require_simd!(ret_ty, "return");
1994         let out_len = ret_ty.simd_size(tcx);
1995         require!(
1996             in_len == out_len,
1997             "expected return type with length {} (same as input type `{}`), \
1998                   found `{}` with length {}",
1999             in_len,
2000             in_ty,
2001             ret_ty,
2002             out_len
2003         );
2004         // casting cares about nominal type, not just structural type
2005         let out_elem = ret_ty.simd_type(tcx);
2006
2007         if in_elem == out_elem {
2008             return Ok(args[0].immediate());
2009         }
2010
2011         enum Style {
2012             Float,
2013             Int(/* is signed? */ bool),
2014             Unsupported,
2015         }
2016
2017         let (in_style, in_width) = match in_elem.kind {
2018             // vectors of pointer-sized integers should've been
2019             // disallowed before here, so this unwrap is safe.
2020             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
2021             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
2022             ty::Float(f) => (Style::Float, f.bit_width()),
2023             _ => (Style::Unsupported, 0),
2024         };
2025         let (out_style, out_width) = match out_elem.kind {
2026             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
2027             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
2028             ty::Float(f) => (Style::Float, f.bit_width()),
2029             _ => (Style::Unsupported, 0),
2030         };
2031
2032         match (in_style, out_style) {
2033             (Style::Int(in_is_signed), Style::Int(_)) => {
2034                 return Ok(match in_width.cmp(&out_width) {
2035                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
2036                     Ordering::Equal => args[0].immediate(),
2037                     Ordering::Less => {
2038                         if in_is_signed {
2039                             bx.sext(args[0].immediate(), llret_ty)
2040                         } else {
2041                             bx.zext(args[0].immediate(), llret_ty)
2042                         }
2043                     }
2044                 });
2045             }
2046             (Style::Int(in_is_signed), Style::Float) => {
2047                 return Ok(if in_is_signed {
2048                     bx.sitofp(args[0].immediate(), llret_ty)
2049                 } else {
2050                     bx.uitofp(args[0].immediate(), llret_ty)
2051                 });
2052             }
2053             (Style::Float, Style::Int(out_is_signed)) => {
2054                 return Ok(if out_is_signed {
2055                     bx.fptosi(args[0].immediate(), llret_ty)
2056                 } else {
2057                     bx.fptoui(args[0].immediate(), llret_ty)
2058                 });
2059             }
2060             (Style::Float, Style::Float) => {
2061                 return Ok(match in_width.cmp(&out_width) {
2062                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
2063                     Ordering::Equal => args[0].immediate(),
2064                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty),
2065                 });
2066             }
2067             _ => { /* Unsupported. Fallthrough. */ }
2068         }
2069         require!(
2070             false,
2071             "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
2072             in_ty,
2073             in_elem,
2074             ret_ty,
2075             out_elem
2076         );
2077     }
2078     macro_rules! arith {
2079         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
2080             $(if name == stringify!($name) {
2081                 match in_elem.kind {
2082                     $($(ty::$p(_))|* => {
2083                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
2084                     })*
2085                     _ => {},
2086                 }
2087                 require!(false,
2088                          "unsupported operation on `{}` with element `{}`",
2089                          in_ty,
2090                          in_elem)
2091             })*
2092         }
2093     }
2094     arith! {
2095         simd_add: Uint, Int => add, Float => fadd;
2096         simd_sub: Uint, Int => sub, Float => fsub;
2097         simd_mul: Uint, Int => mul, Float => fmul;
2098         simd_div: Uint => udiv, Int => sdiv, Float => fdiv;
2099         simd_rem: Uint => urem, Int => srem, Float => frem;
2100         simd_shl: Uint, Int => shl;
2101         simd_shr: Uint => lshr, Int => ashr;
2102         simd_and: Uint, Int => and;
2103         simd_or: Uint, Int => or;
2104         simd_xor: Uint, Int => xor;
2105         simd_fmax: Float => maxnum;
2106         simd_fmin: Float => minnum;
2107
2108     }
2109
2110     if name == "simd_saturating_add" || name == "simd_saturating_sub" {
2111         let lhs = args[0].immediate();
2112         let rhs = args[1].immediate();
2113         let is_add = name == "simd_saturating_add";
2114         let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
2115         let (signed, elem_width, elem_ty) = match in_elem.kind {
2116             ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_int_from_ty(i)),
2117             ty::Uint(i) => (false, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_uint_from_ty(i)),
2118             _ => {
2119                 return_error!(
2120                     "expected element type `{}` of vector type `{}` \
2121                      to be a signed or unsigned integer type",
2122                     arg_tys[0].simd_type(tcx),
2123                     arg_tys[0]
2124                 );
2125             }
2126         };
2127         let llvm_intrinsic = &format!(
2128             "llvm.{}{}.sat.v{}i{}",
2129             if signed { 's' } else { 'u' },
2130             if is_add { "add" } else { "sub" },
2131             in_len,
2132             elem_width
2133         );
2134         let vec_ty = bx.cx.type_vector(elem_ty, in_len as u64);
2135
2136         let f = bx.declare_cfn(&llvm_intrinsic, bx.type_func(&[vec_ty, vec_ty], vec_ty));
2137         llvm::SetUnnamedAddress(f, llvm::UnnamedAddr::No);
2138         let v = bx.call(f, &[lhs, rhs], None);
2139         return Ok(v);
2140     }
2141
2142     span_bug!(span, "unknown SIMD intrinsic");
2143 }
2144
2145 // Returns the width of an int Ty, and if it's signed or not
2146 // Returns None if the type is not an integer
2147 // FIXME: there’s multiple of this functions, investigate using some of the already existing
2148 // stuffs.
2149 fn int_type_width_signed(ty: Ty<'_>, cx: &CodegenCx<'_, '_>) -> Option<(u64, bool)> {
2150     match ty.kind {
2151         ty::Int(t) => Some((
2152             match t {
2153                 ast::IntTy::Isize => u64::from(cx.tcx.sess.target.ptr_width),
2154                 ast::IntTy::I8 => 8,
2155                 ast::IntTy::I16 => 16,
2156                 ast::IntTy::I32 => 32,
2157                 ast::IntTy::I64 => 64,
2158                 ast::IntTy::I128 => 128,
2159             },
2160             true,
2161         )),
2162         ty::Uint(t) => Some((
2163             match t {
2164                 ast::UintTy::Usize => u64::from(cx.tcx.sess.target.ptr_width),
2165                 ast::UintTy::U8 => 8,
2166                 ast::UintTy::U16 => 16,
2167                 ast::UintTy::U32 => 32,
2168                 ast::UintTy::U64 => 64,
2169                 ast::UintTy::U128 => 128,
2170             },
2171             false,
2172         )),
2173         _ => None,
2174     }
2175 }
2176
2177 // Returns the width of a float Ty
2178 // Returns None if the type is not a float
2179 fn float_type_width(ty: Ty<'_>) -> Option<u64> {
2180     match ty.kind {
2181         ty::Float(t) => Some(t.bit_width()),
2182         _ => None,
2183     }
2184 }
2185
2186 fn op_to_u32<'tcx>(op: &Operand<'tcx>) -> u32 {
2187     Operand::scalar_from_const(op).to_u32().expect("Scalar is u32")
2188 }