compiler/rustc_codegen_llvm/src/intrinsic.rs

   1 use crate::abi::{Abi, FnAbi, FnAbiLlvmExt, LlvmType, PassMode};
   2 use crate::builder::Builder;
   3 use crate::context::CodegenCx;
   4 use crate::llvm;
   5 use crate::type_::Type;
   6 use crate::type_of::LayoutLlvmExt;
   7 use crate::va_arg::emit_va_arg;
   8 use crate::value::Value;
   9
  10 use rustc_ast as ast;
  11 use rustc_codegen_ssa::base::{compare_simd_types, wants_msvc_seh};
  12 use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
  13 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
  14 use rustc_codegen_ssa::mir::operand::OperandRef;
  15 use rustc_codegen_ssa::mir::place::PlaceRef;
  16 use rustc_codegen_ssa::traits::*;
  17 use rustc_hir as hir;
  18 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, LayoutOf};
  19 use rustc_middle::ty::{self, Ty};
  20 use rustc_middle::{bug, span_bug};
  21 use rustc_span::{sym, symbol::kw, Span, Symbol};
  22 use rustc_target::abi::{self, HasDataLayout, Primitive};
  23 use rustc_target::spec::{HasTargetSpec, PanicStrategy};
  24
  25 use std::cmp::Ordering;
  26 use std::iter;
  27
  28 fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: Symbol) -> Option<(&'ll Type, &'ll Value)> {
  29     let llvm_name = match name {
  30         sym::sqrtf32 => "llvm.sqrt.f32",
  31         sym::sqrtf64 => "llvm.sqrt.f64",
  32         sym::powif32 => "llvm.powi.f32",
  33         sym::powif64 => "llvm.powi.f64",
  34         sym::sinf32 => "llvm.sin.f32",
  35         sym::sinf64 => "llvm.sin.f64",
  36         sym::cosf32 => "llvm.cos.f32",
  37         sym::cosf64 => "llvm.cos.f64",
  38         sym::powf32 => "llvm.pow.f32",
  39         sym::powf64 => "llvm.pow.f64",
  40         sym::expf32 => "llvm.exp.f32",
  41         sym::expf64 => "llvm.exp.f64",
  42         sym::exp2f32 => "llvm.exp2.f32",
  43         sym::exp2f64 => "llvm.exp2.f64",
  44         sym::logf32 => "llvm.log.f32",
  45         sym::logf64 => "llvm.log.f64",
  46         sym::log10f32 => "llvm.log10.f32",
  47         sym::log10f64 => "llvm.log10.f64",
  48         sym::log2f32 => "llvm.log2.f32",
  49         sym::log2f64 => "llvm.log2.f64",
  50         sym::fmaf32 => "llvm.fma.f32",
  51         sym::fmaf64 => "llvm.fma.f64",
  52         sym::fabsf32 => "llvm.fabs.f32",
  53         sym::fabsf64 => "llvm.fabs.f64",
  54         sym::minnumf32 => "llvm.minnum.f32",
  55         sym::minnumf64 => "llvm.minnum.f64",
  56         sym::maxnumf32 => "llvm.maxnum.f32",
  57         sym::maxnumf64 => "llvm.maxnum.f64",
  58         sym::copysignf32 => "llvm.copysign.f32",
  59         sym::copysignf64 => "llvm.copysign.f64",
  60         sym::floorf32 => "llvm.floor.f32",
  61         sym::floorf64 => "llvm.floor.f64",
  62         sym::ceilf32 => "llvm.ceil.f32",
  63         sym::ceilf64 => "llvm.ceil.f64",
  64         sym::truncf32 => "llvm.trunc.f32",
  65         sym::truncf64 => "llvm.trunc.f64",
  66         sym::rintf32 => "llvm.rint.f32",
  67         sym::rintf64 => "llvm.rint.f64",
  68         sym::nearbyintf32 => "llvm.nearbyint.f32",
  69         sym::nearbyintf64 => "llvm.nearbyint.f64",
  70         sym::roundf32 => "llvm.round.f32",
  71         sym::roundf64 => "llvm.round.f64",
  72         _ => return None,
  73     };
  74     Some(cx.get_intrinsic(llvm_name))
  75 }
  76
  77 impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
  78     fn codegen_intrinsic_call(
  79         &mut self,
  80         instance: ty::Instance<'tcx>,
  81         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
  82         args: &[OperandRef<'tcx, &'ll Value>],
  83         llresult: &'ll Value,
  84         span: Span,
  85     ) {
  86         let tcx = self.tcx;
  87         let callee_ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
  88
  89         let (def_id, substs) = match *callee_ty.kind() {
  90             ty::FnDef(def_id, substs) => (def_id, substs),
  91             _ => bug!("expected fn item type, found {}", callee_ty),
  92         };
  93
  94         let sig = callee_ty.fn_sig(tcx);
  95         let sig = tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig);
  96         let arg_tys = sig.inputs();
  97         let ret_ty = sig.output();
  98         let name = tcx.item_name(def_id);
  99
 100         let llret_ty = self.layout_of(ret_ty).llvm_type(self);
 101         let result = PlaceRef::new_sized(llresult, fn_abi.ret.layout);
 102
 103         let simple = get_simple_intrinsic(self, name);
 104         let llval = match name {
 105             _ if simple.is_some() => {
 106                 let (simple_ty, simple_fn) = simple.unwrap();
 107                 self.call(
 108                     simple_ty,
 109                     simple_fn,
 110                     &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(),
 111                     None,
 112                 )
 113             }
 114             sym::likely => {
 115                 self.call_intrinsic("llvm.expect.i1", &[args[0].immediate(), self.const_bool(true)])
 116             }
 117             sym::unlikely => self
 118                 .call_intrinsic("llvm.expect.i1", &[args[0].immediate(), self.const_bool(false)]),
 119             kw::Try => {
 120                 try_intrinsic(
 121                     self,
 122                     args[0].immediate(),
 123                     args[1].immediate(),
 124                     args[2].immediate(),
 125                     llresult,
 126                 );
 127                 return;
 128             }
 129             sym::breakpoint => self.call_intrinsic("llvm.debugtrap", &[]),
 130             sym::va_copy => {
 131                 self.call_intrinsic("llvm.va_copy", &[args[0].immediate(), args[1].immediate()])
 132             }
 133             sym::va_arg => {
 134                 match fn_abi.ret.layout.abi {
 135                     abi::Abi::Scalar(scalar) => {
 136                         match scalar.value {
 137                             Primitive::Int(..) => {
 138                                 if self.cx().size_of(ret_ty).bytes() < 4 {
 139                                     // `va_arg` should not be called on an integer type
 140                                     // less than 4 bytes in length. If it is, promote
 141                                     // the integer to an `i32` and truncate the result
 142                                     // back to the smaller type.
 143                                     let promoted_result = emit_va_arg(self, args[0], tcx.types.i32);
 144                                     self.trunc(promoted_result, llret_ty)
 145                                 } else {
 146                                     emit_va_arg(self, args[0], ret_ty)
 147                                 }
 148                             }
 149                             Primitive::F64 | Primitive::Pointer => {
 150                                 emit_va_arg(self, args[0], ret_ty)
 151                             }
 152                             // `va_arg` should never be used with the return type f32.
 153                             Primitive::F32 => bug!("the va_arg intrinsic does not work with `f32`"),
 154                         }
 155                     }
 156                     _ => bug!("the va_arg intrinsic does not work with non-scalar types"),
 157                 }
 158             }
 159
 160             sym::volatile_load | sym::unaligned_volatile_load => {
 161                 let tp_ty = substs.type_at(0);
 162                 let ptr = args[0].immediate();
 163                 let load = if let PassMode::Cast(ty) = fn_abi.ret.mode {
 164                     let llty = ty.llvm_type(self);
 165                     let ptr = self.pointercast(ptr, self.type_ptr_to(llty));
 166                     self.volatile_load(llty, ptr)
 167                 } else {
 168                     self.volatile_load(self.layout_of(tp_ty).llvm_type(self), ptr)
 169                 };
 170                 let align = if name == sym::unaligned_volatile_load {
 171                     1
 172                 } else {
 173                     self.align_of(tp_ty).bytes() as u32
 174                 };
 175                 unsafe {
 176                     llvm::LLVMSetAlignment(load, align);
 177                 }
 178                 self.to_immediate(load, self.layout_of(tp_ty))
 179             }
 180             sym::volatile_store => {
 181                 let dst = args[0].deref(self.cx());
 182                 args[1].val.volatile_store(self, dst);
 183                 return;
 184             }
 185             sym::unaligned_volatile_store => {
 186                 let dst = args[0].deref(self.cx());
 187                 args[1].val.unaligned_volatile_store(self, dst);
 188                 return;
 189             }
 190             sym::prefetch_read_data
 191             | sym::prefetch_write_data
 192             | sym::prefetch_read_instruction
 193             | sym::prefetch_write_instruction => {
 194                 let (rw, cache_type) = match name {
 195                     sym::prefetch_read_data => (0, 1),
 196                     sym::prefetch_write_data => (1, 1),
 197                     sym::prefetch_read_instruction => (0, 0),
 198                     sym::prefetch_write_instruction => (1, 0),
 199                     _ => bug!(),
 200                 };
 201                 self.call_intrinsic(
 202                     "llvm.prefetch",
 203                     &[
 204                         args[0].immediate(),
 205                         self.const_i32(rw),
 206                         args[1].immediate(),
 207                         self.const_i32(cache_type),
 208                     ],
 209                 )
 210             }
 211             sym::ctlz
 212             | sym::ctlz_nonzero
 213             | sym::cttz
 214             | sym::cttz_nonzero
 215             | sym::ctpop
 216             | sym::bswap
 217             | sym::bitreverse
 218             | sym::rotate_left
 219             | sym::rotate_right
 220             | sym::saturating_add
 221             | sym::saturating_sub => {
 222                 let ty = arg_tys[0];
 223                 match int_type_width_signed(ty, self) {
 224                     Some((width, signed)) => match name {
 225                         sym::ctlz | sym::cttz => {
 226                             let y = self.const_bool(false);
 227                             self.call_intrinsic(
 228                                 &format!("llvm.{}.i{}", name, width),
 229                                 &[args[0].immediate(), y],
 230                             )
 231                         }
 232                         sym::ctlz_nonzero => {
 233                             let y = self.const_bool(true);
 234                             let llvm_name = &format!("llvm.ctlz.i{}", width);
 235                             self.call_intrinsic(llvm_name, &[args[0].immediate(), y])
 236                         }
 237                         sym::cttz_nonzero => {
 238                             let y = self.const_bool(true);
 239                             let llvm_name = &format!("llvm.cttz.i{}", width);
 240                             self.call_intrinsic(llvm_name, &[args[0].immediate(), y])
 241                         }
 242                         sym::ctpop => self.call_intrinsic(
 243                             &format!("llvm.ctpop.i{}", width),
 244                             &[args[0].immediate()],
 245                         ),
 246                         sym::bswap => {
 247                             if width == 8 {
 248                                 args[0].immediate() // byte swap a u8/i8 is just a no-op
 249                             } else {
 250                                 self.call_intrinsic(
 251                                     &format!("llvm.bswap.i{}", width),
 252                                     &[args[0].immediate()],
 253                                 )
 254                             }
 255                         }
 256                         sym::bitreverse => self.call_intrinsic(
 257                             &format!("llvm.bitreverse.i{}", width),
 258                             &[args[0].immediate()],
 259                         ),
 260                         sym::rotate_left | sym::rotate_right => {
 261                             let is_left = name == sym::rotate_left;
 262                             let val = args[0].immediate();
 263                             let raw_shift = args[1].immediate();
 264                             // rotate = funnel shift with first two args the same
 265                             let llvm_name =
 266                                 &format!("llvm.fsh{}.i{}", if is_left { 'l' } else { 'r' }, width);
 267                             self.call_intrinsic(llvm_name, &[val, val, raw_shift])
 268                         }
 269                         sym::saturating_add | sym::saturating_sub => {
 270                             let is_add = name == sym::saturating_add;
 271                             let lhs = args[0].immediate();
 272                             let rhs = args[1].immediate();
 273                             let llvm_name = &format!(
 274                                 "llvm.{}{}.sat.i{}",
 275                                 if signed { 's' } else { 'u' },
 276                                 if is_add { "add" } else { "sub" },
 277                                 width
 278                             );
 279                             self.call_intrinsic(llvm_name, &[lhs, rhs])
 280                         }
 281                         _ => bug!(),
 282                     },
 283                     None => {
 284                         span_invalid_monomorphization_error(
 285                             tcx.sess,
 286                             span,
 287                             &format!(
 288                                 "invalid monomorphization of `{}` intrinsic: \
 289                                       expected basic integer type, found `{}`",
 290                                 name, ty
 291                             ),
 292                         );
 293                         return;
 294                     }
 295                 }
 296             }
 297
 298             sym::raw_eq => {
 299                 use abi::Abi::*;
 300                 let tp_ty = substs.type_at(0);
 301                 let layout = self.layout_of(tp_ty).layout;
 302                 let use_integer_compare = match layout.abi {
 303                     Scalar(_) | ScalarPair(_, _) => true,
 304                     Uninhabited | Vector { .. } => false,
 305                     Aggregate { .. } => {
 306                         // For rusty ABIs, small aggregates are actually passed
 307                         // as `RegKind::Integer` (see `FnAbi::adjust_for_abi`),
 308                         // so we re-use that same threshold here.
 309                         layout.size <= self.data_layout().pointer_size * 2
 310                     }
 311                 };
 312
 313                 let a = args[0].immediate();
 314                 let b = args[1].immediate();
 315                 if layout.size.bytes() == 0 {
 316                     self.const_bool(true)
 317                 } else if use_integer_compare {
 318                     let integer_ty = self.type_ix(layout.size.bits());
 319                     let ptr_ty = self.type_ptr_to(integer_ty);
 320                     let a_ptr = self.bitcast(a, ptr_ty);
 321                     let a_val = self.load(integer_ty, a_ptr, layout.align.abi);
 322                     let b_ptr = self.bitcast(b, ptr_ty);
 323                     let b_val = self.load(integer_ty, b_ptr, layout.align.abi);
 324                     self.icmp(IntPredicate::IntEQ, a_val, b_val)
 325                 } else {
 326                     let i8p_ty = self.type_i8p();
 327                     let a_ptr = self.bitcast(a, i8p_ty);
 328                     let b_ptr = self.bitcast(b, i8p_ty);
 329                     let n = self.const_usize(layout.size.bytes());
 330                     let cmp = self.call_intrinsic("memcmp", &[a_ptr, b_ptr, n]);
 331                     self.icmp(IntPredicate::IntEQ, cmp, self.const_i32(0))
 332                 }
 333             }
 334
 335             sym::black_box => {
 336                 args[0].val.store(self, result);
 337
 338                 // We need to "use" the argument in some way LLVM can't introspect, and on
 339                 // targets that support it we can typically leverage inline assembly to do
 340                 // this. LLVM's interpretation of inline assembly is that it's, well, a black
 341                 // box. This isn't the greatest implementation since it probably deoptimizes
 342                 // more than we want, but it's so far good enough.
 343                 crate::asm::inline_asm_call(
 344                     self,
 345                     "",
 346                     "r,~{memory}",
 347                     &[result.llval],
 348                     self.type_void(),
 349                     true,
 350                     false,
 351                     ast::LlvmAsmDialect::Att,
 352                     &[span],
 353                 )
 354                 .unwrap_or_else(|| bug!("failed to generate inline asm call for `black_box`"));
 355
 356                 // We have copied the value to `result` already.
 357                 return;
 358             }
 359
 360             _ if name.as_str().starts_with("simd_") => {
 361                 match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
 362                     Ok(llval) => llval,
 363                     Err(()) => return,
 364                 }
 365             }
 366
 367             _ => bug!("unknown intrinsic '{}'", name),
 368         };
 369
 370         if !fn_abi.ret.is_ignore() {
 371             if let PassMode::Cast(ty) = fn_abi.ret.mode {
 372                 let ptr_llty = self.type_ptr_to(ty.llvm_type(self));
 373                 let ptr = self.pointercast(result.llval, ptr_llty);
 374                 self.store(llval, ptr, result.align);
 375             } else {
 376                 OperandRef::from_immediate_or_packed_pair(self, llval, result.layout)
 377                     .val
 378                     .store(self, result);
 379             }
 380         }
 381     }
 382
 383     fn abort(&mut self) {
 384         self.call_intrinsic("llvm.trap", &[]);
 385     }
 386
 387     fn assume(&mut self, val: Self::Value) {
 388         self.call_intrinsic("llvm.assume", &[val]);
 389     }
 390
 391     fn expect(&mut self, cond: Self::Value, expected: bool) -> Self::Value {
 392         self.call_intrinsic("llvm.expect.i1", &[cond, self.const_bool(expected)])
 393     }
 394
 395     fn sideeffect(&mut self) {
 396         // This kind of check would make a ton of sense in the caller, but currently the only
 397         // caller of this function is in `rustc_codegen_ssa`, which is agnostic to whether LLVM
 398         // codegen backend being used, and so is unable to check the LLVM version.
 399         if unsafe { llvm::LLVMRustVersionMajor() } < 12 {
 400             self.call_intrinsic("llvm.sideeffect", &[]);
 401         }
 402     }
 403
 404     fn va_start(&mut self, va_list: &'ll Value) -> &'ll Value {
 405         self.call_intrinsic("llvm.va_start", &[va_list])
 406     }
 407
 408     fn va_end(&mut self, va_list: &'ll Value) -> &'ll Value {
 409         self.call_intrinsic("llvm.va_end", &[va_list])
 410     }
 411 }
 412
 413 fn try_intrinsic(
 414     bx: &mut Builder<'a, 'll, 'tcx>,
 415     try_func: &'ll Value,
 416     data: &'ll Value,
 417     catch_func: &'ll Value,
 418     dest: &'ll Value,
 419 ) {
 420     if bx.sess().panic_strategy() == PanicStrategy::Abort {
 421         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
 422         bx.call(try_func_ty, try_func, &[data], None);
 423         // Return 0 unconditionally from the intrinsic call;
 424         // we can never unwind.
 425         let ret_align = bx.tcx().data_layout.i32_align.abi;
 426         bx.store(bx.const_i32(0), dest, ret_align);
 427     } else if wants_msvc_seh(bx.sess()) {
 428         codegen_msvc_try(bx, try_func, data, catch_func, dest);
 429     } else if bx.sess().target.is_like_emscripten {
 430         codegen_emcc_try(bx, try_func, data, catch_func, dest);
 431     } else {
 432         codegen_gnu_try(bx, try_func, data, catch_func, dest);
 433     }
 434 }
 435
 436 // MSVC's definition of the `rust_try` function.
 437 //
 438 // This implementation uses the new exception handling instructions in LLVM
 439 // which have support in LLVM for SEH on MSVC targets. Although these
 440 // instructions are meant to work for all targets, as of the time of this
 441 // writing, however, LLVM does not recommend the usage of these new instructions
 442 // as the old ones are still more optimized.
 443 fn codegen_msvc_try(
 444     bx: &mut Builder<'a, 'll, 'tcx>,
 445     try_func: &'ll Value,
 446     data: &'ll Value,
 447     catch_func: &'ll Value,
 448     dest: &'ll Value,
 449 ) {
 450     let (llty, llfn) = get_rust_try_fn(bx, &mut |mut bx| {
 451         bx.set_personality_fn(bx.eh_personality());
 452
 453         let mut normal = bx.build_sibling_block("normal");
 454         let mut catchswitch = bx.build_sibling_block("catchswitch");
 455         let mut catchpad_rust = bx.build_sibling_block("catchpad_rust");
 456         let mut catchpad_foreign = bx.build_sibling_block("catchpad_foreign");
 457         let mut caught = bx.build_sibling_block("caught");
 458
 459         let try_func = llvm::get_param(bx.llfn(), 0);
 460         let data = llvm::get_param(bx.llfn(), 1);
 461         let catch_func = llvm::get_param(bx.llfn(), 2);
 462
 463         // We're generating an IR snippet that looks like:
 464         //
 465         //   declare i32 @rust_try(%try_func, %data, %catch_func) {
 466         //      %slot = alloca i8*
 467         //      invoke %try_func(%data) to label %normal unwind label %catchswitch
 468         //
 469         //   normal:
 470         //      ret i32 0
 471         //
 472         //   catchswitch:
 473         //      %cs = catchswitch within none [%catchpad_rust, %catchpad_foreign] unwind to caller
 474         //
 475         //   catchpad_rust:
 476         //      %tok = catchpad within %cs [%type_descriptor, 8, %slot]
 477         //      %ptr = load %slot
 478         //      call %catch_func(%data, %ptr)
 479         //      catchret from %tok to label %caught
 480         //
 481         //   catchpad_foreign:
 482         //      %tok = catchpad within %cs [null, 64, null]
 483         //      call %catch_func(%data, null)
 484         //      catchret from %tok to label %caught
 485         //
 486         //   caught:
 487         //      ret i32 1
 488         //   }
 489         //
 490         // This structure follows the basic usage of throw/try/catch in LLVM.
 491         // For example, compile this C++ snippet to see what LLVM generates:
 492         //
 493         //      struct rust_panic {
 494         //          rust_panic(const rust_panic&);
 495         //          ~rust_panic();
 496         //
 497         //          void* x[2];
 498         //      };
 499         //
 500         //      int __rust_try(
 501         //          void (*try_func)(void*),
 502         //          void *data,
 503         //          void (*catch_func)(void*, void*) noexcept
 504         //      ) {
 505         //          try {
 506         //              try_func(data);
 507         //              return 0;
 508         //          } catch(rust_panic& a) {
 509         //              catch_func(data, &a);
 510         //              return 1;
 511         //          } catch(...) {
 512         //              catch_func(data, NULL);
 513         //              return 1;
 514         //          }
 515         //      }
 516         //
 517         // More information can be found in libstd's seh.rs implementation.
 518         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 519         let slot = bx.alloca(bx.type_i8p(), ptr_align);
 520         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
 521         bx.invoke(try_func_ty, try_func, &[data], normal.llbb(), catchswitch.llbb(), None);
 522
 523         normal.ret(bx.const_i32(0));
 524
 525         let cs = catchswitch.catch_switch(None, None, 2);
 526         catchswitch.add_handler(cs, catchpad_rust.llbb());
 527         catchswitch.add_handler(cs, catchpad_foreign.llbb());
 528
 529         // We can't use the TypeDescriptor defined in libpanic_unwind because it
 530         // might be in another DLL and the SEH encoding only supports specifying
 531         // a TypeDescriptor from the current module.
 532         //
 533         // However this isn't an issue since the MSVC runtime uses string
 534         // comparison on the type name to match TypeDescriptors rather than
 535         // pointer equality.
 536         //
 537         // So instead we generate a new TypeDescriptor in each module that uses
 538         // `try` and let the linker merge duplicate definitions in the same
 539         // module.
 540         //
 541         // When modifying, make sure that the type_name string exactly matches
 542         // the one used in src/libpanic_unwind/seh.rs.
 543         let type_info_vtable = bx.declare_global("??_7type_info@@6B@", bx.type_i8p());
 544         let type_name = bx.const_bytes(b"rust_panic\0");
 545         let type_info =
 546             bx.const_struct(&[type_info_vtable, bx.const_null(bx.type_i8p()), type_name], false);
 547         let tydesc = bx.declare_global("__rust_panic_type_info", bx.val_ty(type_info));
 548         unsafe {
 549             llvm::LLVMRustSetLinkage(tydesc, llvm::Linkage::LinkOnceODRLinkage);
 550             llvm::SetUniqueComdat(bx.llmod, tydesc);
 551             llvm::LLVMSetInitializer(tydesc, type_info);
 552         }
 553
 554         // The flag value of 8 indicates that we are catching the exception by
 555         // reference instead of by value. We can't use catch by value because
 556         // that requires copying the exception object, which we don't support
 557         // since our exception object effectively contains a Box.
 558         //
 559         // Source: MicrosoftCXXABI::getAddrOfCXXCatchHandlerType in clang
 560         let flags = bx.const_i32(8);
 561         let funclet = catchpad_rust.catch_pad(cs, &[tydesc, flags, slot]);
 562         let ptr = catchpad_rust.load(bx.type_i8p(), slot, ptr_align);
 563         let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
 564         catchpad_rust.call(catch_ty, catch_func, &[data, ptr], Some(&funclet));
 565         catchpad_rust.catch_ret(&funclet, caught.llbb());
 566
 567         // The flag value of 64 indicates a "catch-all".
 568         let flags = bx.const_i32(64);
 569         let null = bx.const_null(bx.type_i8p());
 570         let funclet = catchpad_foreign.catch_pad(cs, &[null, flags, null]);
 571         catchpad_foreign.call(catch_ty, catch_func, &[data, null], Some(&funclet));
 572         catchpad_foreign.catch_ret(&funclet, caught.llbb());
 573
 574         caught.ret(bx.const_i32(1));
 575     });
 576
 577     // Note that no invoke is used here because by definition this function
 578     // can't panic (that's what it's catching).
 579     let ret = bx.call(llty, llfn, &[try_func, data, catch_func], None);
 580     let i32_align = bx.tcx().data_layout.i32_align.abi;
 581     bx.store(ret, dest, i32_align);
 582 }
 583
 584 // Definition of the standard `try` function for Rust using the GNU-like model
 585 // of exceptions (e.g., the normal semantics of LLVM's `landingpad` and `invoke`
 586 // instructions).
 587 //
 588 // This codegen is a little surprising because we always call a shim
 589 // function instead of inlining the call to `invoke` manually here. This is done
 590 // because in LLVM we're only allowed to have one personality per function
 591 // definition. The call to the `try` intrinsic is being inlined into the
 592 // function calling it, and that function may already have other personality
 593 // functions in play. By calling a shim we're guaranteed that our shim will have
 594 // the right personality function.
 595 fn codegen_gnu_try(
 596     bx: &mut Builder<'a, 'll, 'tcx>,
 597     try_func: &'ll Value,
 598     data: &'ll Value,
 599     catch_func: &'ll Value,
 600     dest: &'ll Value,
 601 ) {
 602     let (llty, llfn) = get_rust_try_fn(bx, &mut |mut bx| {
 603         // Codegens the shims described above:
 604         //
 605         //   bx:
 606         //      invoke %try_func(%data) normal %normal unwind %catch
 607         //
 608         //   normal:
 609         //      ret 0
 610         //
 611         //   catch:
 612         //      (%ptr, _) = landingpad
 613         //      call %catch_func(%data, %ptr)
 614         //      ret 1
 615         let mut then = bx.build_sibling_block("then");
 616         let mut catch = bx.build_sibling_block("catch");
 617
 618         let try_func = llvm::get_param(bx.llfn(), 0);
 619         let data = llvm::get_param(bx.llfn(), 1);
 620         let catch_func = llvm::get_param(bx.llfn(), 2);
 621         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
 622         bx.invoke(try_func_ty, try_func, &[data], then.llbb(), catch.llbb(), None);
 623         then.ret(bx.const_i32(0));
 624
 625         // Type indicator for the exception being thrown.
 626         //
 627         // The first value in this tuple is a pointer to the exception object
 628         // being thrown.  The second value is a "selector" indicating which of
 629         // the landing pad clauses the exception's type had been matched to.
 630         // rust_try ignores the selector.
 631         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
 632         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 1);
 633         let tydesc = bx.const_null(bx.type_i8p());
 634         catch.add_clause(vals, tydesc);
 635         let ptr = catch.extract_value(vals, 0);
 636         let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
 637         catch.call(catch_ty, catch_func, &[data, ptr], None);
 638         catch.ret(bx.const_i32(1));
 639     });
 640
 641     // Note that no invoke is used here because by definition this function
 642     // can't panic (that's what it's catching).
 643     let ret = bx.call(llty, llfn, &[try_func, data, catch_func], None);
 644     let i32_align = bx.tcx().data_layout.i32_align.abi;
 645     bx.store(ret, dest, i32_align);
 646 }
 647
 648 // Variant of codegen_gnu_try used for emscripten where Rust panics are
 649 // implemented using C++ exceptions. Here we use exceptions of a specific type
 650 // (`struct rust_panic`) to represent Rust panics.
 651 fn codegen_emcc_try(
 652     bx: &mut Builder<'a, 'll, 'tcx>,
 653     try_func: &'ll Value,
 654     data: &'ll Value,
 655     catch_func: &'ll Value,
 656     dest: &'ll Value,
 657 ) {
 658     let (llty, llfn) = get_rust_try_fn(bx, &mut |mut bx| {
 659         // Codegens the shims described above:
 660         //
 661         //   bx:
 662         //      invoke %try_func(%data) normal %normal unwind %catch
 663         //
 664         //   normal:
 665         //      ret 0
 666         //
 667         //   catch:
 668         //      (%ptr, %selector) = landingpad
 669         //      %rust_typeid = @llvm.eh.typeid.for(@_ZTI10rust_panic)
 670         //      %is_rust_panic = %selector == %rust_typeid
 671         //      %catch_data = alloca { i8*, i8 }
 672         //      %catch_data[0] = %ptr
 673         //      %catch_data[1] = %is_rust_panic
 674         //      call %catch_func(%data, %catch_data)
 675         //      ret 1
 676         let mut then = bx.build_sibling_block("then");
 677         let mut catch = bx.build_sibling_block("catch");
 678
 679         let try_func = llvm::get_param(bx.llfn(), 0);
 680         let data = llvm::get_param(bx.llfn(), 1);
 681         let catch_func = llvm::get_param(bx.llfn(), 2);
 682         let try_func_ty = bx.type_func(&[bx.type_i8p()], bx.type_void());
 683         bx.invoke(try_func_ty, try_func, &[data], then.llbb(), catch.llbb(), None);
 684         then.ret(bx.const_i32(0));
 685
 686         // Type indicator for the exception being thrown.
 687         //
 688         // The first value in this tuple is a pointer to the exception object
 689         // being thrown.  The second value is a "selector" indicating which of
 690         // the landing pad clauses the exception's type had been matched to.
 691         let tydesc = bx.eh_catch_typeinfo();
 692         let lpad_ty = bx.type_struct(&[bx.type_i8p(), bx.type_i32()], false);
 693         let vals = catch.landing_pad(lpad_ty, bx.eh_personality(), 2);
 694         catch.add_clause(vals, tydesc);
 695         catch.add_clause(vals, bx.const_null(bx.type_i8p()));
 696         let ptr = catch.extract_value(vals, 0);
 697         let selector = catch.extract_value(vals, 1);
 698
 699         // Check if the typeid we got is the one for a Rust panic.
 700         let rust_typeid = catch.call_intrinsic("llvm.eh.typeid.for", &[tydesc]);
 701         let is_rust_panic = catch.icmp(IntPredicate::IntEQ, selector, rust_typeid);
 702         let is_rust_panic = catch.zext(is_rust_panic, bx.type_bool());
 703
 704         // We need to pass two values to catch_func (ptr and is_rust_panic), so
 705         // create an alloca and pass a pointer to that.
 706         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
 707         let i8_align = bx.tcx().data_layout.i8_align.abi;
 708         let catch_data_type = bx.type_struct(&[bx.type_i8p(), bx.type_bool()], false);
 709         let catch_data = catch.alloca(catch_data_type, ptr_align);
 710         let catch_data_0 = catch.inbounds_gep(
 711             catch_data_type,
 712             catch_data,
 713             &[bx.const_usize(0), bx.const_usize(0)],
 714         );
 715         catch.store(ptr, catch_data_0, ptr_align);
 716         let catch_data_1 = catch.inbounds_gep(
 717             catch_data_type,
 718             catch_data,
 719             &[bx.const_usize(0), bx.const_usize(1)],
 720         );
 721         catch.store(is_rust_panic, catch_data_1, i8_align);
 722         let catch_data = catch.bitcast(catch_data, bx.type_i8p());
 723
 724         let catch_ty = bx.type_func(&[bx.type_i8p(), bx.type_i8p()], bx.type_void());
 725         catch.call(catch_ty, catch_func, &[data, catch_data], None);
 726         catch.ret(bx.const_i32(1));
 727     });
 728
 729     // Note that no invoke is used here because by definition this function
 730     // can't panic (that's what it's catching).
 731     let ret = bx.call(llty, llfn, &[try_func, data, catch_func], None);
 732     let i32_align = bx.tcx().data_layout.i32_align.abi;
 733     bx.store(ret, dest, i32_align);
 734 }
 735
 736 // Helper function to give a Block to a closure to codegen a shim function.
 737 // This is currently primarily used for the `try` intrinsic functions above.
 738 fn gen_fn<'ll, 'tcx>(
 739     cx: &CodegenCx<'ll, 'tcx>,
 740     name: &str,
 741     rust_fn_sig: ty::PolyFnSig<'tcx>,
 742     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 743 ) -> (&'ll Type, &'ll Value) {
 744     let fn_abi = cx.fn_abi_of_fn_ptr(rust_fn_sig, ty::List::empty());
 745     let llty = fn_abi.llvm_type(cx);
 746     let llfn = cx.declare_fn(name, fn_abi);
 747     cx.set_frame_pointer_type(llfn);
 748     cx.apply_target_cpu_attr(llfn);
 749     // FIXME(eddyb) find a nicer way to do this.
 750     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
 751     let llbb = Builder::append_block(cx, llfn, "entry-block");
 752     let bx = Builder::build(cx, llbb);
 753     codegen(bx);
 754     (llty, llfn)
 755 }
 756
 757 // Helper function used to get a handle to the `__rust_try` function used to
 758 // catch exceptions.
 759 //
 760 // This function is only generated once and is then cached.
 761 fn get_rust_try_fn<'ll, 'tcx>(
 762     cx: &CodegenCx<'ll, 'tcx>,
 763     codegen: &mut dyn FnMut(Builder<'_, 'll, 'tcx>),
 764 ) -> (&'ll Type, &'ll Value) {
 765     if let Some(llfn) = cx.rust_try_fn.get() {
 766         return llfn;
 767     }
 768
 769     // Define the type up front for the signature of the rust_try function.
 770     let tcx = cx.tcx;
 771     let i8p = tcx.mk_mut_ptr(tcx.types.i8);
 772     // `unsafe fn(*mut i8) -> ()`
 773     let try_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
 774         iter::once(i8p),
 775         tcx.mk_unit(),
 776         false,
 777         hir::Unsafety::Unsafe,
 778         Abi::Rust,
 779     )));
 780     // `unsafe fn(*mut i8, *mut i8) -> ()`
 781     let catch_fn_ty = tcx.mk_fn_ptr(ty::Binder::dummy(tcx.mk_fn_sig(
 782         [i8p, i8p].iter().cloned(),
 783         tcx.mk_unit(),
 784         false,
 785         hir::Unsafety::Unsafe,
 786         Abi::Rust,
 787     )));
 788     // `unsafe fn(unsafe fn(*mut i8) -> (), *mut i8, unsafe fn(*mut i8, *mut i8) -> ()) -> i32`
 789     let rust_fn_sig = ty::Binder::dummy(cx.tcx.mk_fn_sig(
 790         vec![try_fn_ty, i8p, catch_fn_ty].into_iter(),
 791         tcx.types.i32,
 792         false,
 793         hir::Unsafety::Unsafe,
 794         Abi::Rust,
 795     ));
 796     let rust_try = gen_fn(cx, "__rust_try", rust_fn_sig, codegen);
 797     cx.rust_try_fn.set(Some(rust_try));
 798     rust_try
 799 }
 800
 801 fn generic_simd_intrinsic(
 802     bx: &mut Builder<'a, 'll, 'tcx>,
 803     name: Symbol,
 804     callee_ty: Ty<'tcx>,
 805     args: &[OperandRef<'tcx, &'ll Value>],
 806     ret_ty: Ty<'tcx>,
 807     llret_ty: &'ll Type,
 808     span: Span,
 809 ) -> Result<&'ll Value, ()> {
 810     // macros for error handling:
 811     macro_rules! emit_error {
 812         ($msg: tt) => {
 813             emit_error!($msg, )
 814         };
 815         ($msg: tt, $($fmt: tt)*) => {
 816             span_invalid_monomorphization_error(
 817                 bx.sess(), span,
 818                 &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
 819                          name, $($fmt)*));
 820         }
 821     }
 822
 823     macro_rules! return_error {
 824         ($($fmt: tt)*) => {
 825             {
 826                 emit_error!($($fmt)*);
 827                 return Err(());
 828             }
 829         }
 830     }
 831
 832     macro_rules! require {
 833         ($cond: expr, $($fmt: tt)*) => {
 834             if !$cond {
 835                 return_error!($($fmt)*);
 836             }
 837         };
 838     }
 839
 840     macro_rules! require_simd {
 841         ($ty: expr, $position: expr) => {
 842             require!($ty.is_simd(), "expected SIMD {} type, found non-SIMD `{}`", $position, $ty)
 843         };
 844     }
 845
 846     let tcx = bx.tcx();
 847     let sig =
 848         tcx.normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), callee_ty.fn_sig(tcx));
 849     let arg_tys = sig.inputs();
 850
 851     if name == sym::simd_select_bitmask {
 852         let in_ty = arg_tys[0];
 853         let m_len = match in_ty.kind() {
 854             // Note that this `.unwrap()` crashes for isize/usize, that's sort
 855             // of intentional as there's not currently a use case for that.
 856             ty::Int(i) => i.bit_width().unwrap(),
 857             ty::Uint(i) => i.bit_width().unwrap(),
 858             _ => return_error!("`{}` is not an integral type", in_ty),
 859         };
 860         require_simd!(arg_tys[1], "argument");
 861         let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
 862         require!(
 863             // Allow masks for vectors with fewer than 8 elements to be
 864             // represented with a u8 or i8.
 865             m_len == v_len || (m_len == 8 && v_len < 8),
 866             "mismatched lengths: mask length `{}` != other vector length `{}`",
 867             m_len,
 868             v_len
 869         );
 870         let i1 = bx.type_i1();
 871         let im = bx.type_ix(v_len);
 872         let i1xn = bx.type_vector(i1, v_len);
 873         let m_im = bx.trunc(args[0].immediate(), im);
 874         let m_i1s = bx.bitcast(m_im, i1xn);
 875         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
 876     }
 877
 878     // every intrinsic below takes a SIMD vector as its first argument
 879     require_simd!(arg_tys[0], "input");
 880     let in_ty = arg_tys[0];
 881
 882     let comparison = match name {
 883         sym::simd_eq => Some(hir::BinOpKind::Eq),
 884         sym::simd_ne => Some(hir::BinOpKind::Ne),
 885         sym::simd_lt => Some(hir::BinOpKind::Lt),
 886         sym::simd_le => Some(hir::BinOpKind::Le),
 887         sym::simd_gt => Some(hir::BinOpKind::Gt),
 888         sym::simd_ge => Some(hir::BinOpKind::Ge),
 889         _ => None,
 890     };
 891
 892     let (in_len, in_elem) = arg_tys[0].simd_size_and_type(bx.tcx());
 893     if let Some(cmp_op) = comparison {
 894         require_simd!(ret_ty, "return");
 895
 896         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
 897         require!(
 898             in_len == out_len,
 899             "expected return type with length {} (same as input type `{}`), \
 900              found `{}` with length {}",
 901             in_len,
 902             in_ty,
 903             ret_ty,
 904             out_len
 905         );
 906         require!(
 907             bx.type_kind(bx.element_type(llret_ty)) == TypeKind::Integer,
 908             "expected return type with integer elements, found `{}` with non-integer `{}`",
 909             ret_ty,
 910             out_ty
 911         );
 912
 913         return Ok(compare_simd_types(
 914             bx,
 915             args[0].immediate(),
 916             args[1].immediate(),
 917             in_elem,
 918             llret_ty,
 919             cmp_op,
 920         ));
 921     }
 922
 923     if let Some(stripped) = name.as_str().strip_prefix("simd_shuffle") {
 924         // If this intrinsic is the older "simd_shuffleN" form, simply parse the integer.
 925         // If there is no suffix, use the index array length.
 926         let n: u64 = if stripped.is_empty() {
 927             // Make sure this is actually an array, since typeck only checks the length-suffixed
 928             // version of this intrinsic.
 929             match args[2].layout.ty.kind() {
 930                 ty::Array(ty, len) if matches!(ty.kind(), ty::Uint(ty::UintTy::U32)) => {
 931                     len.try_eval_usize(bx.cx.tcx, ty::ParamEnv::reveal_all()).unwrap_or_else(|| {
 932                         span_bug!(span, "could not evaluate shuffle index array length")
 933                     })
 934                 }
 935                 _ => return_error!(
 936                     "simd_shuffle index must be an array of `u32`, got `{}`",
 937                     args[2].layout.ty
 938                 ),
 939             }
 940         } else {
 941             stripped.parse().unwrap_or_else(|_| {
 942                 span_bug!(span, "bad `simd_shuffle` instruction only caught in codegen?")
 943             })
 944         };
 945
 946         require_simd!(ret_ty, "return");
 947         let (out_len, out_ty) = ret_ty.simd_size_and_type(bx.tcx());
 948         require!(
 949             out_len == n,
 950             "expected return type of length {}, found `{}` with length {}",
 951             n,
 952             ret_ty,
 953             out_len
 954         );
 955         require!(
 956             in_elem == out_ty,
 957             "expected return element type `{}` (element of input `{}`), \
 958              found `{}` with element type `{}`",
 959             in_elem,
 960             in_ty,
 961             ret_ty,
 962             out_ty
 963         );
 964
 965         let total_len = u128::from(in_len) * 2;
 966
 967         let vector = args[2].immediate();
 968
 969         let indices: Option<Vec<_>> = (0..n)
 970             .map(|i| {
 971                 let arg_idx = i;
 972                 let val = bx.const_get_elt(vector, i as u64);
 973                 match bx.const_to_opt_u128(val, true) {
 974                     None => {
 975                         emit_error!("shuffle index #{} is not a constant", arg_idx);
 976                         None
 977                     }
 978                     Some(idx) if idx >= total_len => {
 979                         emit_error!(
 980                             "shuffle index #{} is out of bounds (limit {})",
 981                             arg_idx,
 982                             total_len
 983                         );
 984                         None
 985                     }
 986                     Some(idx) => Some(bx.const_i32(idx as i32)),
 987                 }
 988             })
 989             .collect();
 990         let indices = match indices {
 991             Some(i) => i,
 992             None => return Ok(bx.const_null(llret_ty)),
 993         };
 994
 995         return Ok(bx.shuffle_vector(
 996             args[0].immediate(),
 997             args[1].immediate(),
 998             bx.const_vector(&indices),
 999         ));
1000     }
1001
1002     if name == sym::simd_insert {
1003         require!(
1004             in_elem == arg_tys[2],
1005             "expected inserted type `{}` (element of input `{}`), found `{}`",
1006             in_elem,
1007             in_ty,
1008             arg_tys[2]
1009         );
1010         return Ok(bx.insert_element(
1011             args[0].immediate(),
1012             args[2].immediate(),
1013             args[1].immediate(),
1014         ));
1015     }
1016     if name == sym::simd_extract {
1017         require!(
1018             ret_ty == in_elem,
1019             "expected return type `{}` (element of input `{}`), found `{}`",
1020             in_elem,
1021             in_ty,
1022             ret_ty
1023         );
1024         return Ok(bx.extract_element(args[0].immediate(), args[1].immediate()));
1025     }
1026
1027     if name == sym::simd_select {
1028         let m_elem_ty = in_elem;
1029         let m_len = in_len;
1030         require_simd!(arg_tys[1], "argument");
1031         let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
1032         require!(
1033             m_len == v_len,
1034             "mismatched lengths: mask length `{}` != other vector length `{}`",
1035             m_len,
1036             v_len
1037         );
1038         match m_elem_ty.kind() {
1039             ty::Int(_) => {}
1040             _ => return_error!("mask element type is `{}`, expected `i_`", m_elem_ty),
1041         }
1042         // truncate the mask to a vector of i1s
1043         let i1 = bx.type_i1();
1044         let i1xn = bx.type_vector(i1, m_len as u64);
1045         let m_i1s = bx.trunc(args[0].immediate(), i1xn);
1046         return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
1047     }
1048
1049     if name == sym::simd_bitmask {
1050         // The `fn simd_bitmask(vector) -> unsigned integer` intrinsic takes a
1051         // vector mask and returns an unsigned integer containing the most
1052         // significant bit (MSB) of each lane.
1053
1054         // If the vector has less than 8 lanes, a u8 is returned with zeroed
1055         // trailing bits.
1056         let expected_int_bits = in_len.max(8);
1057         match ret_ty.kind() {
1058             ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => (),
1059             _ => return_error!("bitmask `{}`, expected `u{}`", ret_ty, expected_int_bits),
1060         }
1061
1062         // Integer vector <i{in_bitwidth} x in_len>:
1063         let (i_xn, in_elem_bitwidth) = match in_elem.kind() {
1064             ty::Int(i) => (
1065                 args[0].immediate(),
1066                 i.bit_width().unwrap_or_else(|| bx.data_layout().pointer_size.bits()),
1067             ),
1068             ty::Uint(i) => (
1069                 args[0].immediate(),
1070                 i.bit_width().unwrap_or_else(|| bx.data_layout().pointer_size.bits()),
1071             ),
1072             _ => return_error!(
1073                 "vector argument `{}`'s element type `{}`, expected integer element type",
1074                 in_ty,
1075                 in_elem
1076             ),
1077         };
1078
1079         // Shift the MSB to the right by "in_elem_bitwidth - 1" into the first bit position.
1080         let shift_indices =
1081             vec![
1082                 bx.cx.const_int(bx.type_ix(in_elem_bitwidth), (in_elem_bitwidth - 1) as _);
1083                 in_len as _
1084             ];
1085         let i_xn_msb = bx.lshr(i_xn, bx.const_vector(shift_indices.as_slice()));
1086         // Truncate vector to an <i1 x N>
1087         let i1xn = bx.trunc(i_xn_msb, bx.type_vector(bx.type_i1(), in_len));
1088         // Bitcast <i1 x N> to iN:
1089         let i_ = bx.bitcast(i1xn, bx.type_ix(in_len));
1090         // Zero-extend iN to the bitmask type:
1091         return Ok(bx.zext(i_, bx.type_ix(expected_int_bits)));
1092     }
1093
1094     fn simd_simple_float_intrinsic(
1095         name: Symbol,
1096         in_elem: &::rustc_middle::ty::TyS<'_>,
1097         in_ty: &::rustc_middle::ty::TyS<'_>,
1098         in_len: u64,
1099         bx: &mut Builder<'a, 'll, 'tcx>,
1100         span: Span,
1101         args: &[OperandRef<'tcx, &'ll Value>],
1102     ) -> Result<&'ll Value, ()> {
1103         macro_rules! emit_error {
1104             ($msg: tt) => {
1105                 emit_error!($msg, )
1106             };
1107             ($msg: tt, $($fmt: tt)*) => {
1108                 span_invalid_monomorphization_error(
1109                     bx.sess(), span,
1110                     &format!(concat!("invalid monomorphization of `{}` intrinsic: ", $msg),
1111                              name, $($fmt)*));
1112             }
1113         }
1114         macro_rules! return_error {
1115             ($($fmt: tt)*) => {
1116                 {
1117                     emit_error!($($fmt)*);
1118                     return Err(());
1119                 }
1120             }
1121         }
1122
1123         let (elem_ty_str, elem_ty) = if let ty::Float(f) = in_elem.kind() {
1124             let elem_ty = bx.cx.type_float_from_ty(*f);
1125             match f.bit_width() {
1126                 32 => ("f32", elem_ty),
1127                 64 => ("f64", elem_ty),
1128                 _ => {
1129                     return_error!(
1130                         "unsupported element type `{}` of floating-point vector `{}`",
1131                         f.name_str(),
1132                         in_ty
1133                     );
1134                 }
1135             }
1136         } else {
1137             return_error!("`{}` is not a floating-point type", in_ty);
1138         };
1139
1140         let vec_ty = bx.type_vector(elem_ty, in_len);
1141
1142         let (intr_name, fn_ty) = match name {
1143             sym::simd_ceil => ("ceil", bx.type_func(&[vec_ty], vec_ty)),
1144             sym::simd_fabs => ("fabs", bx.type_func(&[vec_ty], vec_ty)),
1145             sym::simd_fcos => ("cos", bx.type_func(&[vec_ty], vec_ty)),
1146             sym::simd_fexp2 => ("exp2", bx.type_func(&[vec_ty], vec_ty)),
1147             sym::simd_fexp => ("exp", bx.type_func(&[vec_ty], vec_ty)),
1148             sym::simd_flog10 => ("log10", bx.type_func(&[vec_ty], vec_ty)),
1149             sym::simd_flog2 => ("log2", bx.type_func(&[vec_ty], vec_ty)),
1150             sym::simd_flog => ("log", bx.type_func(&[vec_ty], vec_ty)),
1151             sym::simd_floor => ("floor", bx.type_func(&[vec_ty], vec_ty)),
1152             sym::simd_fma => ("fma", bx.type_func(&[vec_ty, vec_ty, vec_ty], vec_ty)),
1153             sym::simd_fpowi => ("powi", bx.type_func(&[vec_ty, bx.type_i32()], vec_ty)),
1154             sym::simd_fpow => ("pow", bx.type_func(&[vec_ty, vec_ty], vec_ty)),
1155             sym::simd_fsin => ("sin", bx.type_func(&[vec_ty], vec_ty)),
1156             sym::simd_fsqrt => ("sqrt", bx.type_func(&[vec_ty], vec_ty)),
1157             sym::simd_round => ("round", bx.type_func(&[vec_ty], vec_ty)),
1158             sym::simd_trunc => ("trunc", bx.type_func(&[vec_ty], vec_ty)),
1159             _ => return_error!("unrecognized intrinsic `{}`", name),
1160         };
1161         let llvm_name = &format!("llvm.{0}.v{1}{2}", intr_name, in_len, elem_ty_str);
1162         let f = bx.declare_cfn(llvm_name, llvm::UnnamedAddr::No, fn_ty);
1163         let c =
1164             bx.call(fn_ty, f, &args.iter().map(|arg| arg.immediate()).collect::<Vec<_>>(), None);
1165         Ok(c)
1166     }
1167
1168     if std::matches!(
1169         name,
1170         sym::simd_ceil
1171             | sym::simd_fabs
1172             | sym::simd_fcos
1173             | sym::simd_fexp2
1174             | sym::simd_fexp
1175             | sym::simd_flog10
1176             | sym::simd_flog2
1177             | sym::simd_flog
1178             | sym::simd_floor
1179             | sym::simd_fma
1180             | sym::simd_fpow
1181             | sym::simd_fpowi
1182             | sym::simd_fsin
1183             | sym::simd_fsqrt
1184             | sym::simd_round
1185             | sym::simd_trunc
1186     ) {
1187         return simd_simple_float_intrinsic(name, in_elem, in_ty, in_len, bx, span, args);
1188     }
1189
1190     // FIXME: use:
1191     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Function.h#L182
1192     //  https://github.com/llvm-mirror/llvm/blob/master/include/llvm/IR/Intrinsics.h#L81
1193     fn llvm_vector_str(
1194         elem_ty: Ty<'_>,
1195         vec_len: u64,
1196         no_pointers: usize,
1197         bx: &Builder<'a, 'll, 'tcx>,
1198     ) -> String {
1199         let p0s: String = "p0".repeat(no_pointers);
1200         match *elem_ty.kind() {
1201             ty::Int(v) => format!(
1202                 "v{}{}i{}",
1203                 vec_len,
1204                 p0s,
1205                 // Normalize to prevent crash if v: IntTy::Isize
1206                 v.normalize(bx.target_spec().pointer_width).bit_width().unwrap()
1207             ),
1208             ty::Uint(v) => format!(
1209                 "v{}{}i{}",
1210                 vec_len,
1211                 p0s,
1212                 // Normalize to prevent crash if v: UIntTy::Usize
1213                 v.normalize(bx.target_spec().pointer_width).bit_width().unwrap()
1214             ),
1215             ty::Float(v) => format!("v{}{}f{}", vec_len, p0s, v.bit_width()),
1216             _ => unreachable!(),
1217         }
1218     }
1219
1220     fn llvm_vector_ty(
1221         cx: &CodegenCx<'ll, '_>,
1222         elem_ty: Ty<'_>,
1223         vec_len: u64,
1224         mut no_pointers: usize,
1225     ) -> &'ll Type {
1226         // FIXME: use cx.layout_of(ty).llvm_type() ?
1227         let mut elem_ty = match *elem_ty.kind() {
1228             ty::Int(v) => cx.type_int_from_ty(v),
1229             ty::Uint(v) => cx.type_uint_from_ty(v),
1230             ty::Float(v) => cx.type_float_from_ty(v),
1231             _ => unreachable!(),
1232         };
1233         while no_pointers > 0 {
1234             elem_ty = cx.type_ptr_to(elem_ty);
1235             no_pointers -= 1;
1236         }
1237         cx.type_vector(elem_ty, vec_len)
1238     }
1239
1240     if name == sym::simd_gather {
1241         // simd_gather(values: <N x T>, pointers: <N x *_ T>,
1242         //             mask: <N x i{M}>) -> <N x T>
1243         // * N: number of elements in the input vectors
1244         // * T: type of the element to load
1245         // * M: any integer width is supported, will be truncated to i1
1246
1247         // All types must be simd vector types
1248         require_simd!(in_ty, "first");
1249         require_simd!(arg_tys[1], "second");
1250         require_simd!(arg_tys[2], "third");
1251         require_simd!(ret_ty, "return");
1252
1253         // Of the same length:
1254         let (out_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
1255         let (out_len2, _) = arg_tys[2].simd_size_and_type(bx.tcx());
1256         require!(
1257             in_len == out_len,
1258             "expected {} argument with length {} (same as input type `{}`), \
1259              found `{}` with length {}",
1260             "second",
1261             in_len,
1262             in_ty,
1263             arg_tys[1],
1264             out_len
1265         );
1266         require!(
1267             in_len == out_len2,
1268             "expected {} argument with length {} (same as input type `{}`), \
1269              found `{}` with length {}",
1270             "third",
1271             in_len,
1272             in_ty,
1273             arg_tys[2],
1274             out_len2
1275         );
1276
1277         // The return type must match the first argument type
1278         require!(ret_ty == in_ty, "expected return type `{}`, found `{}`", in_ty, ret_ty);
1279
1280         // This counts how many pointers
1281         fn ptr_count(t: Ty<'_>) -> usize {
1282             match t.kind() {
1283                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1284                 _ => 0,
1285             }
1286         }
1287
1288         // Non-ptr type
1289         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1290             match t.kind() {
1291                 ty::RawPtr(p) => non_ptr(p.ty),
1292                 _ => t,
1293             }
1294         }
1295
1296         // The second argument must be a simd vector with an element type that's a pointer
1297         // to the element type of the first argument
1298         let (_, element_ty0) = arg_tys[0].simd_size_and_type(bx.tcx());
1299         let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
1300         let (pointer_count, underlying_ty) = match element_ty1.kind() {
1301             ty::RawPtr(p) if p.ty == in_elem => (ptr_count(element_ty1), non_ptr(element_ty1)),
1302             _ => {
1303                 require!(
1304                     false,
1305                     "expected element type `{}` of second argument `{}` \
1306                         to be a pointer to the element type `{}` of the first \
1307                         argument `{}`, found `{}` != `*_ {}`",
1308                     element_ty1,
1309                     arg_tys[1],
1310                     in_elem,
1311                     in_ty,
1312                     element_ty1,
1313                     in_elem
1314                 );
1315                 unreachable!();
1316             }
1317         };
1318         assert!(pointer_count > 0);
1319         assert_eq!(pointer_count - 1, ptr_count(element_ty0));
1320         assert_eq!(underlying_ty, non_ptr(element_ty0));
1321
1322         // The element type of the third argument must be a signed integer type of any width:
1323         let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
1324         match element_ty2.kind() {
1325             ty::Int(_) => (),
1326             _ => {
1327                 require!(
1328                     false,
1329                     "expected element type `{}` of third argument `{}` \
1330                                  to be a signed integer type",
1331                     element_ty2,
1332                     arg_tys[2]
1333                 );
1334             }
1335         }
1336
1337         // Alignment of T, must be a constant integer value:
1338         let alignment_ty = bx.type_i32();
1339         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1340
1341         // Truncate the mask vector to a vector of i1s:
1342         let (mask, mask_ty) = {
1343             let i1 = bx.type_i1();
1344             let i1xn = bx.type_vector(i1, in_len);
1345             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1346         };
1347
1348         // Type of the vector of pointers:
1349         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1350         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count, bx);
1351
1352         // Type of the vector of elements:
1353         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1354         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1, bx);
1355
1356         let llvm_intrinsic =
1357             format!("llvm.masked.gather.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1358         let fn_ty = bx.type_func(
1359             &[llvm_pointer_vec_ty, alignment_ty, mask_ty, llvm_elem_vec_ty],
1360             llvm_elem_vec_ty,
1361         );
1362         let f = bx.declare_cfn(&llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
1363         let v =
1364             bx.call(fn_ty, f, &[args[1].immediate(), alignment, mask, args[0].immediate()], None);
1365         return Ok(v);
1366     }
1367
1368     if name == sym::simd_scatter {
1369         // simd_scatter(values: <N x T>, pointers: <N x *mut T>,
1370         //             mask: <N x i{M}>) -> ()
1371         // * N: number of elements in the input vectors
1372         // * T: type of the element to load
1373         // * M: any integer width is supported, will be truncated to i1
1374
1375         // All types must be simd vector types
1376         require_simd!(in_ty, "first");
1377         require_simd!(arg_tys[1], "second");
1378         require_simd!(arg_tys[2], "third");
1379
1380         // Of the same length:
1381         let (element_len1, _) = arg_tys[1].simd_size_and_type(bx.tcx());
1382         let (element_len2, _) = arg_tys[2].simd_size_and_type(bx.tcx());
1383         require!(
1384             in_len == element_len1,
1385             "expected {} argument with length {} (same as input type `{}`), \
1386             found `{}` with length {}",
1387             "second",
1388             in_len,
1389             in_ty,
1390             arg_tys[1],
1391             element_len1
1392         );
1393         require!(
1394             in_len == element_len2,
1395             "expected {} argument with length {} (same as input type `{}`), \
1396             found `{}` with length {}",
1397             "third",
1398             in_len,
1399             in_ty,
1400             arg_tys[2],
1401             element_len2
1402         );
1403
1404         // This counts how many pointers
1405         fn ptr_count(t: Ty<'_>) -> usize {
1406             match t.kind() {
1407                 ty::RawPtr(p) => 1 + ptr_count(p.ty),
1408                 _ => 0,
1409             }
1410         }
1411
1412         // Non-ptr type
1413         fn non_ptr(t: Ty<'_>) -> Ty<'_> {
1414             match t.kind() {
1415                 ty::RawPtr(p) => non_ptr(p.ty),
1416                 _ => t,
1417             }
1418         }
1419
1420         // The second argument must be a simd vector with an element type that's a pointer
1421         // to the element type of the first argument
1422         let (_, element_ty0) = arg_tys[0].simd_size_and_type(bx.tcx());
1423         let (_, element_ty1) = arg_tys[1].simd_size_and_type(bx.tcx());
1424         let (_, element_ty2) = arg_tys[2].simd_size_and_type(bx.tcx());
1425         let (pointer_count, underlying_ty) = match element_ty1.kind() {
1426             ty::RawPtr(p) if p.ty == in_elem && p.mutbl == hir::Mutability::Mut => {
1427                 (ptr_count(element_ty1), non_ptr(element_ty1))
1428             }
1429             _ => {
1430                 require!(
1431                     false,
1432                     "expected element type `{}` of second argument `{}` \
1433                         to be a pointer to the element type `{}` of the first \
1434                         argument `{}`, found `{}` != `*mut {}`",
1435                     element_ty1,
1436                     arg_tys[1],
1437                     in_elem,
1438                     in_ty,
1439                     element_ty1,
1440                     in_elem
1441                 );
1442                 unreachable!();
1443             }
1444         };
1445         assert!(pointer_count > 0);
1446         assert_eq!(pointer_count - 1, ptr_count(element_ty0));
1447         assert_eq!(underlying_ty, non_ptr(element_ty0));
1448
1449         // The element type of the third argument must be a signed integer type of any width:
1450         match element_ty2.kind() {
1451             ty::Int(_) => (),
1452             _ => {
1453                 require!(
1454                     false,
1455                     "expected element type `{}` of third argument `{}` \
1456                          be a signed integer type",
1457                     element_ty2,
1458                     arg_tys[2]
1459                 );
1460             }
1461         }
1462
1463         // Alignment of T, must be a constant integer value:
1464         let alignment_ty = bx.type_i32();
1465         let alignment = bx.const_i32(bx.align_of(in_elem).bytes() as i32);
1466
1467         // Truncate the mask vector to a vector of i1s:
1468         let (mask, mask_ty) = {
1469             let i1 = bx.type_i1();
1470             let i1xn = bx.type_vector(i1, in_len);
1471             (bx.trunc(args[2].immediate(), i1xn), i1xn)
1472         };
1473
1474         let ret_t = bx.type_void();
1475
1476         // Type of the vector of pointers:
1477         let llvm_pointer_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count);
1478         let llvm_pointer_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count, bx);
1479
1480         // Type of the vector of elements:
1481         let llvm_elem_vec_ty = llvm_vector_ty(bx, underlying_ty, in_len, pointer_count - 1);
1482         let llvm_elem_vec_str = llvm_vector_str(underlying_ty, in_len, pointer_count - 1, bx);
1483
1484         let llvm_intrinsic =
1485             format!("llvm.masked.scatter.{}.{}", llvm_elem_vec_str, llvm_pointer_vec_str);
1486         let fn_ty =
1487             bx.type_func(&[llvm_elem_vec_ty, llvm_pointer_vec_ty, alignment_ty, mask_ty], ret_t);
1488         let f = bx.declare_cfn(&llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
1489         let v =
1490             bx.call(fn_ty, f, &[args[0].immediate(), args[1].immediate(), alignment, mask], None);
1491         return Ok(v);
1492     }
1493
1494     macro_rules! arith_red {
1495         ($name:ident : $integer_reduce:ident, $float_reduce:ident, $ordered:expr, $op:ident,
1496          $identity:expr) => {
1497             if name == sym::$name {
1498                 require!(
1499                     ret_ty == in_elem,
1500                     "expected return type `{}` (element of input `{}`), found `{}`",
1501                     in_elem,
1502                     in_ty,
1503                     ret_ty
1504                 );
1505                 return match in_elem.kind() {
1506                     ty::Int(_) | ty::Uint(_) => {
1507                         let r = bx.$integer_reduce(args[0].immediate());
1508                         if $ordered {
1509                             // if overflow occurs, the result is the
1510                             // mathematical result modulo 2^n:
1511                             Ok(bx.$op(args[1].immediate(), r))
1512                         } else {
1513                             Ok(bx.$integer_reduce(args[0].immediate()))
1514                         }
1515                     }
1516                     ty::Float(f) => {
1517                         let acc = if $ordered {
1518                             // ordered arithmetic reductions take an accumulator
1519                             args[1].immediate()
1520                         } else {
1521                             // unordered arithmetic reductions use the identity accumulator
1522                             match f.bit_width() {
1523                                 32 => bx.const_real(bx.type_f32(), $identity),
1524                                 64 => bx.const_real(bx.type_f64(), $identity),
1525                                 v => return_error!(
1526                                     r#"
1527 unsupported {} from `{}` with element `{}` of size `{}` to `{}`"#,
1528                                     sym::$name,
1529                                     in_ty,
1530                                     in_elem,
1531                                     v,
1532                                     ret_ty
1533                                 ),
1534                             }
1535                         };
1536                         Ok(bx.$float_reduce(acc, args[0].immediate()))
1537                     }
1538                     _ => return_error!(
1539                         "unsupported {} from `{}` with element `{}` to `{}`",
1540                         sym::$name,
1541                         in_ty,
1542                         in_elem,
1543                         ret_ty
1544                     ),
1545                 };
1546             }
1547         };
1548     }
1549
1550     arith_red!(simd_reduce_add_ordered: vector_reduce_add, vector_reduce_fadd, true, add, 0.0);
1551     arith_red!(simd_reduce_mul_ordered: vector_reduce_mul, vector_reduce_fmul, true, mul, 1.0);
1552     arith_red!(
1553         simd_reduce_add_unordered: vector_reduce_add,
1554         vector_reduce_fadd_fast,
1555         false,
1556         add,
1557         0.0
1558     );
1559     arith_red!(
1560         simd_reduce_mul_unordered: vector_reduce_mul,
1561         vector_reduce_fmul_fast,
1562         false,
1563         mul,
1564         1.0
1565     );
1566
1567     macro_rules! minmax_red {
1568         ($name:ident: $int_red:ident, $float_red:ident) => {
1569             if name == sym::$name {
1570                 require!(
1571                     ret_ty == in_elem,
1572                     "expected return type `{}` (element of input `{}`), found `{}`",
1573                     in_elem,
1574                     in_ty,
1575                     ret_ty
1576                 );
1577                 return match in_elem.kind() {
1578                     ty::Int(_i) => Ok(bx.$int_red(args[0].immediate(), true)),
1579                     ty::Uint(_u) => Ok(bx.$int_red(args[0].immediate(), false)),
1580                     ty::Float(_f) => Ok(bx.$float_red(args[0].immediate())),
1581                     _ => return_error!(
1582                         "unsupported {} from `{}` with element `{}` to `{}`",
1583                         sym::$name,
1584                         in_ty,
1585                         in_elem,
1586                         ret_ty
1587                     ),
1588                 };
1589             }
1590         };
1591     }
1592
1593     minmax_red!(simd_reduce_min: vector_reduce_min, vector_reduce_fmin);
1594     minmax_red!(simd_reduce_max: vector_reduce_max, vector_reduce_fmax);
1595
1596     minmax_red!(simd_reduce_min_nanless: vector_reduce_min, vector_reduce_fmin_fast);
1597     minmax_red!(simd_reduce_max_nanless: vector_reduce_max, vector_reduce_fmax_fast);
1598
1599     macro_rules! bitwise_red {
1600         ($name:ident : $red:ident, $boolean:expr) => {
1601             if name == sym::$name {
1602                 let input = if !$boolean {
1603                     require!(
1604                         ret_ty == in_elem,
1605                         "expected return type `{}` (element of input `{}`), found `{}`",
1606                         in_elem,
1607                         in_ty,
1608                         ret_ty
1609                     );
1610                     args[0].immediate()
1611                 } else {
1612                     match in_elem.kind() {
1613                         ty::Int(_) | ty::Uint(_) => {}
1614                         _ => return_error!(
1615                             "unsupported {} from `{}` with element `{}` to `{}`",
1616                             sym::$name,
1617                             in_ty,
1618                             in_elem,
1619                             ret_ty
1620                         ),
1621                     }
1622
1623                     // boolean reductions operate on vectors of i1s:
1624                     let i1 = bx.type_i1();
1625                     let i1xn = bx.type_vector(i1, in_len as u64);
1626                     bx.trunc(args[0].immediate(), i1xn)
1627                 };
1628                 return match in_elem.kind() {
1629                     ty::Int(_) | ty::Uint(_) => {
1630                         let r = bx.$red(input);
1631                         Ok(if !$boolean { r } else { bx.zext(r, bx.type_bool()) })
1632                     }
1633                     _ => return_error!(
1634                         "unsupported {} from `{}` with element `{}` to `{}`",
1635                         sym::$name,
1636                         in_ty,
1637                         in_elem,
1638                         ret_ty
1639                     ),
1640                 };
1641             }
1642         };
1643     }
1644
1645     bitwise_red!(simd_reduce_and: vector_reduce_and, false);
1646     bitwise_red!(simd_reduce_or: vector_reduce_or, false);
1647     bitwise_red!(simd_reduce_xor: vector_reduce_xor, false);
1648     bitwise_red!(simd_reduce_all: vector_reduce_and, true);
1649     bitwise_red!(simd_reduce_any: vector_reduce_or, true);
1650
1651     if name == sym::simd_cast {
1652         require_simd!(ret_ty, "return");
1653         let (out_len, out_elem) = ret_ty.simd_size_and_type(bx.tcx());
1654         require!(
1655             in_len == out_len,
1656             "expected return type with length {} (same as input type `{}`), \
1657                   found `{}` with length {}",
1658             in_len,
1659             in_ty,
1660             ret_ty,
1661             out_len
1662         );
1663         // casting cares about nominal type, not just structural type
1664         if in_elem == out_elem {
1665             return Ok(args[0].immediate());
1666         }
1667
1668         enum Style {
1669             Float,
1670             Int(/* is signed? */ bool),
1671             Unsupported,
1672         }
1673
1674         let (in_style, in_width) = match in_elem.kind() {
1675             // vectors of pointer-sized integers should've been
1676             // disallowed before here, so this unwrap is safe.
1677             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1678             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1679             ty::Float(f) => (Style::Float, f.bit_width()),
1680             _ => (Style::Unsupported, 0),
1681         };
1682         let (out_style, out_width) = match out_elem.kind() {
1683             ty::Int(i) => (Style::Int(true), i.bit_width().unwrap()),
1684             ty::Uint(u) => (Style::Int(false), u.bit_width().unwrap()),
1685             ty::Float(f) => (Style::Float, f.bit_width()),
1686             _ => (Style::Unsupported, 0),
1687         };
1688
1689         match (in_style, out_style) {
1690             (Style::Int(in_is_signed), Style::Int(_)) => {
1691                 return Ok(match in_width.cmp(&out_width) {
1692                     Ordering::Greater => bx.trunc(args[0].immediate(), llret_ty),
1693                     Ordering::Equal => args[0].immediate(),
1694                     Ordering::Less => {
1695                         if in_is_signed {
1696                             bx.sext(args[0].immediate(), llret_ty)
1697                         } else {
1698                             bx.zext(args[0].immediate(), llret_ty)
1699                         }
1700                     }
1701                 });
1702             }
1703             (Style::Int(in_is_signed), Style::Float) => {
1704                 return Ok(if in_is_signed {
1705                     bx.sitofp(args[0].immediate(), llret_ty)
1706                 } else {
1707                     bx.uitofp(args[0].immediate(), llret_ty)
1708                 });
1709             }
1710             (Style::Float, Style::Int(out_is_signed)) => {
1711                 return Ok(if out_is_signed {
1712                     bx.fptosi(args[0].immediate(), llret_ty)
1713                 } else {
1714                     bx.fptoui(args[0].immediate(), llret_ty)
1715                 });
1716             }
1717             (Style::Float, Style::Float) => {
1718                 return Ok(match in_width.cmp(&out_width) {
1719                     Ordering::Greater => bx.fptrunc(args[0].immediate(), llret_ty),
1720                     Ordering::Equal => args[0].immediate(),
1721                     Ordering::Less => bx.fpext(args[0].immediate(), llret_ty),
1722                 });
1723             }
1724             _ => { /* Unsupported. Fallthrough. */ }
1725         }
1726         require!(
1727             false,
1728             "unsupported cast from `{}` with element `{}` to `{}` with element `{}`",
1729             in_ty,
1730             in_elem,
1731             ret_ty,
1732             out_elem
1733         );
1734     }
1735     macro_rules! arith_binary {
1736         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1737             $(if name == sym::$name {
1738                 match in_elem.kind() {
1739                     $($(ty::$p(_))|* => {
1740                         return Ok(bx.$call(args[0].immediate(), args[1].immediate()))
1741                     })*
1742                     _ => {},
1743                 }
1744                 require!(false,
1745                          "unsupported operation on `{}` with element `{}`",
1746                          in_ty,
1747                          in_elem)
1748             })*
1749         }
1750     }
1751     arith_binary! {
1752         simd_add: Uint, Int => add, Float => fadd;
1753         simd_sub: Uint, Int => sub, Float => fsub;
1754         simd_mul: Uint, Int => mul, Float => fmul;
1755         simd_div: Uint => udiv, Int => sdiv, Float => fdiv;
1756         simd_rem: Uint => urem, Int => srem, Float => frem;
1757         simd_shl: Uint, Int => shl;
1758         simd_shr: Uint => lshr, Int => ashr;
1759         simd_and: Uint, Int => and;
1760         simd_or: Uint, Int => or;
1761         simd_xor: Uint, Int => xor;
1762         simd_fmax: Float => maxnum;
1763         simd_fmin: Float => minnum;
1764
1765     }
1766     macro_rules! arith_unary {
1767         ($($name: ident: $($($p: ident),* => $call: ident),*;)*) => {
1768             $(if name == sym::$name {
1769                 match in_elem.kind() {
1770                     $($(ty::$p(_))|* => {
1771                         return Ok(bx.$call(args[0].immediate()))
1772                     })*
1773                     _ => {},
1774                 }
1775                 require!(false,
1776                          "unsupported operation on `{}` with element `{}`",
1777                          in_ty,
1778                          in_elem)
1779             })*
1780         }
1781     }
1782     arith_unary! {
1783         simd_neg: Int => neg, Float => fneg;
1784     }
1785
1786     if name == sym::simd_saturating_add || name == sym::simd_saturating_sub {
1787         let lhs = args[0].immediate();
1788         let rhs = args[1].immediate();
1789         let is_add = name == sym::simd_saturating_add;
1790         let ptr_bits = bx.tcx().data_layout.pointer_size.bits() as _;
1791         let (signed, elem_width, elem_ty) = match *in_elem.kind() {
1792             ty::Int(i) => (true, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_int_from_ty(i)),
1793             ty::Uint(i) => (false, i.bit_width().unwrap_or(ptr_bits), bx.cx.type_uint_from_ty(i)),
1794             _ => {
1795                 return_error!(
1796                     "expected element type `{}` of vector type `{}` \
1797                      to be a signed or unsigned integer type",
1798                     arg_tys[0].simd_size_and_type(bx.tcx()).1,
1799                     arg_tys[0]
1800                 );
1801             }
1802         };
1803         let llvm_intrinsic = &format!(
1804             "llvm.{}{}.sat.v{}i{}",
1805             if signed { 's' } else { 'u' },
1806             if is_add { "add" } else { "sub" },
1807             in_len,
1808             elem_width
1809         );
1810         let vec_ty = bx.cx.type_vector(elem_ty, in_len as u64);
1811
1812         let fn_ty = bx.type_func(&[vec_ty, vec_ty], vec_ty);
1813         let f = bx.declare_cfn(llvm_intrinsic, llvm::UnnamedAddr::No, fn_ty);
1814         let v = bx.call(fn_ty, f, &[lhs, rhs], None);
1815         return Ok(v);
1816     }
1817
1818     span_bug!(span, "unknown SIMD intrinsic");
1819 }
1820
1821 // Returns the width of an int Ty, and if it's signed or not
1822 // Returns None if the type is not an integer
1823 // FIXME: there’s multiple of this functions, investigate using some of the already existing
1824 // stuffs.
1825 fn int_type_width_signed(ty: Ty<'_>, cx: &CodegenCx<'_, '_>) -> Option<(u64, bool)> {
1826     match ty.kind() {
1827         ty::Int(t) => {
1828             Some((t.bit_width().unwrap_or(u64::from(cx.tcx.sess.target.pointer_width)), true))
1829         }
1830         ty::Uint(t) => {
1831             Some((t.bit_width().unwrap_or(u64::from(cx.tcx.sess.target.pointer_width)), false))
1832         }
1833         _ => None,
1834     }
1835 }