compiler/rustc_codegen_llvm/src/intrinsic.rs

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