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