src/librustc_trans/mir/constant.rs

   1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use llvm::{self, ValueRef};
  12 use rustc::middle::const_val::ConstVal;
  13 use rustc_const_eval::{ErrKind, ConstEvalErr, report_const_eval_err};
  14 use rustc_const_math::ConstInt::*;
  15 use rustc_const_math::ConstFloat::*;
  16 use rustc_const_math::{ConstInt, ConstMathErr};
  17 use rustc::hir::def_id::DefId;
  18 use rustc::infer::TransNormalize;
  19 use rustc::mir;
  20 use rustc::mir::tcx::LvalueTy;
  21 use rustc::ty::{self, layout, Ty, TyCtxt, TypeFoldable};
  22 use rustc::ty::cast::{CastTy, IntTy};
  23 use rustc::ty::subst::Substs;
  24 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
  25 use {abi, adt, base, Disr, machine};
  26 use callee::Callee;
  27 use builder::Builder;
  28 use common::{self, CrateContext, const_get_elt, val_ty};
  29 use common::{C_array, C_bool, C_bytes, C_floating_f64, C_integral, C_big_integral};
  30 use common::{C_null, C_struct, C_str_slice, C_undef, C_uint, C_vector, is_undef};
  31 use common::const_to_opt_u128;
  32 use consts;
  33 use monomorphize::{self, Instance};
  34 use type_of;
  35 use type_::Type;
  36 use value::Value;
  37
  38 use syntax_pos::Span;
  39
  40 use std::fmt;
  41 use std::ptr;
  42
  43 use super::lvalue::Alignment;
  44 use super::operand::{OperandRef, OperandValue};
  45 use super::MirContext;
  46
  47 /// A sized constant rvalue.
  48 /// The LLVM type might not be the same for a single Rust type,
  49 /// e.g. each enum variant would have its own LLVM struct type.
  50 #[derive(Copy, Clone)]
  51 pub struct Const<'tcx> {
  52     pub llval: ValueRef,
  53     pub ty: Ty<'tcx>
  54 }
  55
  56 impl<'tcx> Const<'tcx> {
  57     pub fn new(llval: ValueRef, ty: Ty<'tcx>) -> Const<'tcx> {
  58         Const {
  59             llval: llval,
  60             ty: ty
  61         }
  62     }
  63
  64     /// Translate ConstVal into a LLVM constant value.
  65     pub fn from_constval<'a>(ccx: &CrateContext<'a, 'tcx>,
  66                              cv: ConstVal,
  67                              ty: Ty<'tcx>)
  68                              -> Const<'tcx> {
  69         let llty = type_of::type_of(ccx, ty);
  70         let val = match cv {
  71             ConstVal::Float(F32(v)) => C_floating_f64(v as f64, llty),
  72             ConstVal::Float(F64(v)) => C_floating_f64(v, llty),
  73             ConstVal::Float(FInfer {..}) => bug!("MIR must not use `{:?}`", cv),
  74             ConstVal::Bool(v) => C_bool(ccx, v),
  75             ConstVal::Integral(I8(v)) => C_integral(Type::i8(ccx), v as u64, true),
  76             ConstVal::Integral(I16(v)) => C_integral(Type::i16(ccx), v as u64, true),
  77             ConstVal::Integral(I32(v)) => C_integral(Type::i32(ccx), v as u64, true),
  78             ConstVal::Integral(I64(v)) => C_integral(Type::i64(ccx), v as u64, true),
  79             ConstVal::Integral(I128(v)) => C_big_integral(Type::i128(ccx), v as u128),
  80             ConstVal::Integral(Isize(v)) => {
  81                 let i = v.as_i64(ccx.tcx().sess.target.int_type);
  82                 C_integral(Type::int(ccx), i as u64, true)
  83             },
  84             ConstVal::Integral(U8(v)) => C_integral(Type::i8(ccx), v as u64, false),
  85             ConstVal::Integral(U16(v)) => C_integral(Type::i16(ccx), v as u64, false),
  86             ConstVal::Integral(U32(v)) => C_integral(Type::i32(ccx), v as u64, false),
  87             ConstVal::Integral(U64(v)) => C_integral(Type::i64(ccx), v, false),
  88             ConstVal::Integral(U128(v)) => C_big_integral(Type::i128(ccx), v),
  89             ConstVal::Integral(Usize(v)) => {
  90                 let u = v.as_u64(ccx.tcx().sess.target.uint_type);
  91                 C_integral(Type::int(ccx), u, false)
  92             },
  93             ConstVal::Integral(Infer(_)) |
  94             ConstVal::Integral(InferSigned(_)) => bug!("MIR must not use `{:?}`", cv),
  95             ConstVal::Str(ref v) => C_str_slice(ccx, v.clone()),
  96             ConstVal::ByteStr(ref v) => consts::addr_of(ccx, C_bytes(ccx, v), 1, "byte_str"),
  97             ConstVal::Struct(_) | ConstVal::Tuple(_) |
  98             ConstVal::Array(..) | ConstVal::Repeat(..) |
  99             ConstVal::Function(_) => {
 100                 bug!("MIR must not use `{:?}` (which refers to a local ID)", cv)
 101             }
 102             ConstVal::Char(c) => C_integral(Type::char(ccx), c as u64, false),
 103         };
 104
 105         assert!(!ty.has_erasable_regions());
 106
 107         Const::new(val, ty)
 108     }
 109
 110     fn get_pair(&self) -> (ValueRef, ValueRef) {
 111         (const_get_elt(self.llval, &[0]),
 112          const_get_elt(self.llval, &[1]))
 113     }
 114
 115     fn get_fat_ptr(&self) -> (ValueRef, ValueRef) {
 116         assert_eq!(abi::FAT_PTR_ADDR, 0);
 117         assert_eq!(abi::FAT_PTR_EXTRA, 1);
 118         self.get_pair()
 119     }
 120
 121     fn as_lvalue(&self) -> ConstLvalue<'tcx> {
 122         ConstLvalue {
 123             base: Base::Value(self.llval),
 124             llextra: ptr::null_mut(),
 125             ty: self.ty
 126         }
 127     }
 128
 129     pub fn to_operand<'a>(&self, ccx: &CrateContext<'a, 'tcx>) -> OperandRef<'tcx> {
 130         let llty = type_of::immediate_type_of(ccx, self.ty);
 131         let llvalty = val_ty(self.llval);
 132
 133         let val = if llty == llvalty && common::type_is_imm_pair(ccx, self.ty) {
 134             let (a, b) = self.get_pair();
 135             OperandValue::Pair(a, b)
 136         } else if llty == llvalty && common::type_is_immediate(ccx, self.ty) {
 137             // If the types match, we can use the value directly.
 138             OperandValue::Immediate(self.llval)
 139         } else {
 140             // Otherwise, or if the value is not immediate, we create
 141             // a constant LLVM global and cast its address if necessary.
 142             let align = type_of::align_of(ccx, self.ty);
 143             let ptr = consts::addr_of(ccx, self.llval, align, "const");
 144             OperandValue::Ref(consts::ptrcast(ptr, llty.ptr_to()), Alignment::AbiAligned)
 145         };
 146
 147         OperandRef {
 148             val: val,
 149             ty: self.ty
 150         }
 151     }
 152 }
 153
 154 impl<'tcx> fmt::Debug for Const<'tcx> {
 155     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 156         write!(f, "Const({:?}: {:?})", Value(self.llval), self.ty)
 157     }
 158 }
 159
 160 #[derive(Copy, Clone)]
 161 enum Base {
 162     /// A constant value without an unique address.
 163     Value(ValueRef),
 164
 165     /// String literal base pointer (cast from array).
 166     Str(ValueRef),
 167
 168     /// The address of a static.
 169     Static(ValueRef)
 170 }
 171
 172 /// An lvalue as seen from a constant.
 173 #[derive(Copy, Clone)]
 174 struct ConstLvalue<'tcx> {
 175     base: Base,
 176     llextra: ValueRef,
 177     ty: Ty<'tcx>
 178 }
 179
 180 impl<'tcx> ConstLvalue<'tcx> {
 181     fn to_const(&self, span: Span) -> Const<'tcx> {
 182         match self.base {
 183             Base::Value(val) => Const::new(val, self.ty),
 184             Base::Str(ptr) => {
 185                 span_bug!(span, "loading from `str` ({:?}) in constant",
 186                           Value(ptr))
 187             }
 188             Base::Static(val) => {
 189                 span_bug!(span, "loading from `static` ({:?}) in constant",
 190                           Value(val))
 191             }
 192         }
 193     }
 194
 195     pub fn len<'a>(&self, ccx: &CrateContext<'a, 'tcx>) -> ValueRef {
 196         match self.ty.sty {
 197             ty::TyArray(_, n) => C_uint(ccx, n),
 198             ty::TySlice(_) | ty::TyStr => {
 199                 assert!(self.llextra != ptr::null_mut());
 200                 self.llextra
 201             }
 202             _ => bug!("unexpected type `{}` in ConstLvalue::len", self.ty)
 203         }
 204     }
 205 }
 206
 207 /// Machinery for translating a constant's MIR to LLVM values.
 208 /// FIXME(eddyb) use miri and lower its allocations to LLVM.
 209 struct MirConstContext<'a, 'tcx: 'a> {
 210     ccx: &'a CrateContext<'a, 'tcx>,
 211     mir: &'a mir::Mir<'tcx>,
 212
 213     /// Type parameters for const fn and associated constants.
 214     substs: &'tcx Substs<'tcx>,
 215
 216     /// Values of locals in a constant or const fn.
 217     locals: IndexVec<mir::Local, Option<Const<'tcx>>>
 218 }
 219
 220
 221 impl<'a, 'tcx> MirConstContext<'a, 'tcx> {
 222     fn new(ccx: &'a CrateContext<'a, 'tcx>,
 223            mir: &'a mir::Mir<'tcx>,
 224            substs: &'tcx Substs<'tcx>,
 225            args: IndexVec<mir::Local, Const<'tcx>>)
 226            -> MirConstContext<'a, 'tcx> {
 227         let mut context = MirConstContext {
 228             ccx: ccx,
 229             mir: mir,
 230             substs: substs,
 231             locals: (0..mir.local_decls.len()).map(|_| None).collect(),
 232         };
 233         for (i, arg) in args.into_iter().enumerate() {
 234             // Locals after local 0 are the function arguments
 235             let index = mir::Local::new(i + 1);
 236             context.locals[index] = Some(arg);
 237         }
 238         context
 239     }
 240
 241     fn trans_def(ccx: &'a CrateContext<'a, 'tcx>,
 242                  instance: Instance<'tcx>,
 243                  args: IndexVec<mir::Local, Const<'tcx>>)
 244                  -> Result<Const<'tcx>, ConstEvalErr> {
 245         let instance = instance.resolve_const(ccx.shared());
 246         let mir = ccx.tcx().item_mir(instance.def);
 247         MirConstContext::new(ccx, &mir, instance.substs, args).trans()
 248     }
 249
 250     fn monomorphize<T>(&self, value: &T) -> T
 251         where T: TransNormalize<'tcx>
 252     {
 253         monomorphize::apply_param_substs(self.ccx.shared(),
 254                                          self.substs,
 255                                          value)
 256     }
 257
 258     fn trans(&mut self) -> Result<Const<'tcx>, ConstEvalErr> {
 259         let tcx = self.ccx.tcx();
 260         let mut bb = mir::START_BLOCK;
 261
 262         // Make sure to evaluate all statemenets to
 263         // report as many errors as we possibly can.
 264         let mut failure = Ok(());
 265
 266         loop {
 267             let data = &self.mir[bb];
 268             for statement in &data.statements {
 269                 let span = statement.source_info.span;
 270                 match statement.kind {
 271                     mir::StatementKind::Assign(ref dest, ref rvalue) => {
 272                         let ty = dest.ty(self.mir, tcx);
 273                         let ty = self.monomorphize(&ty).to_ty(tcx);
 274                         match self.const_rvalue(rvalue, ty, span) {
 275                             Ok(value) => self.store(dest, value, span),
 276                             Err(err) => if failure.is_ok() { failure = Err(err); }
 277                         }
 278                     }
 279                     mir::StatementKind::StorageLive(_) |
 280                     mir::StatementKind::StorageDead(_) |
 281                     mir::StatementKind::Nop => {}
 282                     mir::StatementKind::SetDiscriminant{ .. } => {
 283                         span_bug!(span, "SetDiscriminant should not appear in constants?");
 284                     }
 285                 }
 286             }
 287
 288             let terminator = data.terminator();
 289             let span = terminator.source_info.span;
 290             bb = match terminator.kind {
 291                 mir::TerminatorKind::Drop { target, .. } | // No dropping.
 292                 mir::TerminatorKind::Goto { target } => target,
 293                 mir::TerminatorKind::Return => {
 294                     failure?;
 295                     return Ok(self.locals[mir::RETURN_POINTER].unwrap_or_else(|| {
 296                         span_bug!(span, "no returned value in constant");
 297                     }));
 298                 }
 299
 300                 mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, .. } => {
 301                     let cond = self.const_operand(cond, span)?;
 302                     let cond_bool = common::const_to_uint(cond.llval) != 0;
 303                     if cond_bool != expected {
 304                         let err = match *msg {
 305                             mir::AssertMessage::BoundsCheck { ref len, ref index } => {
 306                                 let len = self.const_operand(len, span)?;
 307                                 let index = self.const_operand(index, span)?;
 308                                 ErrKind::IndexOutOfBounds {
 309                                     len: common::const_to_uint(len.llval),
 310                                     index: common::const_to_uint(index.llval)
 311                                 }
 312                             }
 313                             mir::AssertMessage::Math(ref err) => {
 314                                 ErrKind::Math(err.clone())
 315                             }
 316                         };
 317
 318                         let err = ConstEvalErr{ span: span, kind: err };
 319                         report_const_eval_err(tcx, &err, span, "expression").emit();
 320                         failure = Err(err);
 321                     }
 322                     target
 323                 }
 324
 325                 mir::TerminatorKind::Call { ref func, ref args, ref destination, .. } => {
 326                     let fn_ty = func.ty(self.mir, tcx);
 327                     let fn_ty = self.monomorphize(&fn_ty);
 328                     let instance = match fn_ty.sty {
 329                         ty::TyFnDef(def_id, substs, _) => {
 330                             Instance::new(def_id, substs)
 331                         }
 332                         _ => span_bug!(span, "calling {:?} (of type {}) in constant",
 333                                        func, fn_ty)
 334                     };
 335
 336                     let mut const_args = IndexVec::with_capacity(args.len());
 337                     for arg in args {
 338                         match self.const_operand(arg, span) {
 339                             Ok(arg) => { const_args.push(arg); },
 340                             Err(err) => if failure.is_ok() { failure = Err(err); }
 341                         }
 342                     }
 343                     if let Some((ref dest, target)) = *destination {
 344                         match MirConstContext::trans_def(self.ccx, instance, const_args) {
 345                             Ok(value) => self.store(dest, value, span),
 346                             Err(err) => if failure.is_ok() { failure = Err(err); }
 347                         }
 348                         target
 349                     } else {
 350                         span_bug!(span, "diverging {:?} in constant", terminator.kind);
 351                     }
 352                 }
 353                 _ => span_bug!(span, "{:?} in constant", terminator.kind)
 354             };
 355         }
 356     }
 357
 358     fn store(&mut self, dest: &mir::Lvalue<'tcx>, value: Const<'tcx>, span: Span) {
 359         if let mir::Lvalue::Local(index) = *dest {
 360             self.locals[index] = Some(value);
 361         } else {
 362             span_bug!(span, "assignment to {:?} in constant", dest);
 363         }
 364     }
 365
 366     fn const_lvalue(&self, lvalue: &mir::Lvalue<'tcx>, span: Span)
 367                     -> Result<ConstLvalue<'tcx>, ConstEvalErr> {
 368         let tcx = self.ccx.tcx();
 369
 370         if let mir::Lvalue::Local(index) = *lvalue {
 371             return Ok(self.locals[index].unwrap_or_else(|| {
 372                 span_bug!(span, "{:?} not initialized", lvalue)
 373             }).as_lvalue());
 374         }
 375
 376         let lvalue = match *lvalue {
 377             mir::Lvalue::Local(_)  => bug!(), // handled above
 378             mir::Lvalue::Static(def_id) => {
 379                 ConstLvalue {
 380                     base: Base::Static(consts::get_static(self.ccx, def_id)),
 381                     llextra: ptr::null_mut(),
 382                     ty: lvalue.ty(self.mir, tcx).to_ty(tcx)
 383                 }
 384             }
 385             mir::Lvalue::Projection(ref projection) => {
 386                 let tr_base = self.const_lvalue(&projection.base, span)?;
 387                 let projected_ty = LvalueTy::Ty { ty: tr_base.ty }
 388                     .projection_ty(tcx, &projection.elem);
 389                 let base = tr_base.to_const(span);
 390                 let projected_ty = self.monomorphize(&projected_ty).to_ty(tcx);
 391                 let is_sized = self.ccx.shared().type_is_sized(projected_ty);
 392
 393                 let (projected, llextra) = match projection.elem {
 394                     mir::ProjectionElem::Deref => {
 395                         let (base, extra) = if is_sized {
 396                             (base.llval, ptr::null_mut())
 397                         } else {
 398                             base.get_fat_ptr()
 399                         };
 400                         if self.ccx.statics().borrow().contains_key(&base) {
 401                             (Base::Static(base), extra)
 402                         } else if let ty::TyStr = projected_ty.sty {
 403                             (Base::Str(base), extra)
 404                         } else {
 405                             let v = base;
 406                             let v = self.ccx.const_unsized().borrow().get(&v).map_or(v, |&v| v);
 407                             let mut val = unsafe { llvm::LLVMGetInitializer(v) };
 408                             if val.is_null() {
 409                                 span_bug!(span, "dereference of non-constant pointer `{:?}`",
 410                                           Value(base));
 411                             }
 412                             if projected_ty.is_bool() {
 413                                 unsafe {
 414                                     val = llvm::LLVMConstTrunc(val, Type::i1(self.ccx).to_ref());
 415                                 }
 416                             }
 417                             (Base::Value(val), extra)
 418                         }
 419                     }
 420                     mir::ProjectionElem::Field(ref field, _) => {
 421                         let llprojected = adt::const_get_field(self.ccx, tr_base.ty, base.llval,
 422                                                                Disr(0), field.index());
 423                         let llextra = if is_sized {
 424                             ptr::null_mut()
 425                         } else {
 426                             tr_base.llextra
 427                         };
 428                         (Base::Value(llprojected), llextra)
 429                     }
 430                     mir::ProjectionElem::Index(ref index) => {
 431                         let llindex = self.const_operand(index, span)?.llval;
 432
 433                         let iv = if let Some(iv) = common::const_to_opt_u128(llindex, false) {
 434                             iv
 435                         } else {
 436                             span_bug!(span, "index is not an integer-constant expression")
 437                         };
 438
 439                         // Produce an undef instead of a LLVM assertion on OOB.
 440                         let len = common::const_to_uint(tr_base.len(self.ccx));
 441                         let llelem = if iv < len as u128 {
 442                             const_get_elt(base.llval, &[iv as u32])
 443                         } else {
 444                             C_undef(type_of::type_of(self.ccx, projected_ty))
 445                         };
 446
 447                         (Base::Value(llelem), ptr::null_mut())
 448                     }
 449                     _ => span_bug!(span, "{:?} in constant", projection.elem)
 450                 };
 451                 ConstLvalue {
 452                     base: projected,
 453                     llextra: llextra,
 454                     ty: projected_ty
 455                 }
 456             }
 457         };
 458         Ok(lvalue)
 459     }
 460
 461     fn const_operand(&self, operand: &mir::Operand<'tcx>, span: Span)
 462                      -> Result<Const<'tcx>, ConstEvalErr> {
 463         debug!("const_operand({:?} @ {:?})", operand, span);
 464         let result = match *operand {
 465             mir::Operand::Consume(ref lvalue) => {
 466                 Ok(self.const_lvalue(lvalue, span)?.to_const(span))
 467             }
 468
 469             mir::Operand::Constant(ref constant) => {
 470                 let ty = self.monomorphize(&constant.ty);
 471                 match constant.literal.clone() {
 472                     mir::Literal::Item { def_id, substs } => {
 473                         // Shortcut for zero-sized types, including function item
 474                         // types, which would not work with MirConstContext.
 475                         if common::type_is_zero_size(self.ccx, ty) {
 476                             let llty = type_of::type_of(self.ccx, ty);
 477                             return Ok(Const::new(C_null(llty), ty));
 478                         }
 479
 480                         let substs = self.monomorphize(&substs);
 481                         let instance = Instance::new(def_id, substs);
 482                         MirConstContext::trans_def(self.ccx, instance, IndexVec::new())
 483                     }
 484                     mir::Literal::Promoted { index } => {
 485                         let mir = &self.mir.promoted[index];
 486                         MirConstContext::new(self.ccx, mir, self.substs, IndexVec::new()).trans()
 487                     }
 488                     mir::Literal::Value { value } => {
 489                         Ok(Const::from_constval(self.ccx, value, ty))
 490                     }
 491                 }
 492             }
 493         };
 494         debug!("const_operand({:?} @ {:?}) = {:?}", operand, span,
 495                result.as_ref().ok());
 496         result
 497     }
 498
 499     fn const_array(&self, array_ty: Ty<'tcx>, fields: &[ValueRef])
 500                    -> Const<'tcx>
 501     {
 502         let elem_ty = array_ty.builtin_index().unwrap_or_else(|| {
 503             bug!("bad array type {:?}", array_ty)
 504         });
 505         let llunitty = type_of::type_of(self.ccx, elem_ty);
 506         // If the array contains enums, an LLVM array won't work.
 507         let val = if fields.iter().all(|&f| val_ty(f) == llunitty) {
 508             C_array(llunitty, fields)
 509         } else {
 510             C_struct(self.ccx, fields, false)
 511         };
 512         Const::new(val, array_ty)
 513     }
 514
 515     fn const_rvalue(&self, rvalue: &mir::Rvalue<'tcx>,
 516                     dest_ty: Ty<'tcx>, span: Span)
 517                     -> Result<Const<'tcx>, ConstEvalErr> {
 518         let tcx = self.ccx.tcx();
 519         debug!("const_rvalue({:?}: {:?} @ {:?})", rvalue, dest_ty, span);
 520         let val = match *rvalue {
 521             mir::Rvalue::Use(ref operand) => self.const_operand(operand, span)?,
 522
 523             mir::Rvalue::Repeat(ref elem, ref count) => {
 524                 let elem = self.const_operand(elem, span)?;
 525                 let size = count.value.as_u64(tcx.sess.target.uint_type);
 526                 let fields = vec![elem.llval; size as usize];
 527                 self.const_array(dest_ty, &fields)
 528             }
 529
 530             mir::Rvalue::Aggregate(ref kind, ref operands) => {
 531                 // Make sure to evaluate all operands to
 532                 // report as many errors as we possibly can.
 533                 let mut fields = Vec::with_capacity(operands.len());
 534                 let mut failure = Ok(());
 535                 for operand in operands {
 536                     match self.const_operand(operand, span) {
 537                         Ok(val) => fields.push(val.llval),
 538                         Err(err) => if failure.is_ok() { failure = Err(err); }
 539                     }
 540                 }
 541                 failure?;
 542
 543                 match *kind {
 544                     mir::AggregateKind::Array => {
 545                         self.const_array(dest_ty, &fields)
 546                     }
 547                     mir::AggregateKind::Adt(..) |
 548                     mir::AggregateKind::Closure(..) |
 549                     mir::AggregateKind::Tuple => {
 550                         Const::new(trans_const(self.ccx, dest_ty, kind, &fields), dest_ty)
 551                     }
 552                 }
 553             }
 554
 555             mir::Rvalue::Cast(ref kind, ref source, cast_ty) => {
 556                 let operand = self.const_operand(source, span)?;
 557                 let cast_ty = self.monomorphize(&cast_ty);
 558
 559                 let val = match *kind {
 560                     mir::CastKind::ReifyFnPointer => {
 561                         match operand.ty.sty {
 562                             ty::TyFnDef(def_id, substs, _) => {
 563                                 Callee::def(self.ccx, def_id, substs)
 564                                     .reify(self.ccx)
 565                             }
 566                             _ => {
 567                                 span_bug!(span, "{} cannot be reified to a fn ptr",
 568                                           operand.ty)
 569                             }
 570                         }
 571                     }
 572                     mir::CastKind::UnsafeFnPointer => {
 573                         // this is a no-op at the LLVM level
 574                         operand.llval
 575                     }
 576                     mir::CastKind::Unsize => {
 577                         // unsize targets other than to a fat pointer currently
 578                         // can't be in constants.
 579                         assert!(common::type_is_fat_ptr(self.ccx, cast_ty));
 580
 581                         let pointee_ty = operand.ty.builtin_deref(true, ty::NoPreference)
 582                             .expect("consts: unsizing got non-pointer type").ty;
 583                         let (base, old_info) = if !self.ccx.shared().type_is_sized(pointee_ty) {
 584                             // Normally, the source is a thin pointer and we are
 585                             // adding extra info to make a fat pointer. The exception
 586                             // is when we are upcasting an existing object fat pointer
 587                             // to use a different vtable. In that case, we want to
 588                             // load out the original data pointer so we can repackage
 589                             // it.
 590                             let (base, extra) = operand.get_fat_ptr();
 591                             (base, Some(extra))
 592                         } else {
 593                             (operand.llval, None)
 594                         };
 595
 596                         let unsized_ty = cast_ty.builtin_deref(true, ty::NoPreference)
 597                             .expect("consts: unsizing got non-pointer target type").ty;
 598                         let ptr_ty = type_of::in_memory_type_of(self.ccx, unsized_ty).ptr_to();
 599                         let base = consts::ptrcast(base, ptr_ty);
 600                         let info = base::unsized_info(self.ccx, pointee_ty,
 601                                                       unsized_ty, old_info);
 602
 603                         if old_info.is_none() {
 604                             let prev_const = self.ccx.const_unsized().borrow_mut()
 605                                                      .insert(base, operand.llval);
 606                             assert!(prev_const.is_none() || prev_const == Some(operand.llval));
 607                         }
 608                         assert_eq!(abi::FAT_PTR_ADDR, 0);
 609                         assert_eq!(abi::FAT_PTR_EXTRA, 1);
 610                         C_struct(self.ccx, &[base, info], false)
 611                     }
 612                     mir::CastKind::Misc if common::type_is_immediate(self.ccx, operand.ty) => {
 613                         debug_assert!(common::type_is_immediate(self.ccx, cast_ty));
 614                         let r_t_in = CastTy::from_ty(operand.ty).expect("bad input type for cast");
 615                         let r_t_out = CastTy::from_ty(cast_ty).expect("bad output type for cast");
 616                         let ll_t_out = type_of::immediate_type_of(self.ccx, cast_ty);
 617                         let llval = operand.llval;
 618                         let signed = if let CastTy::Int(IntTy::CEnum) = r_t_in {
 619                             let l = self.ccx.layout_of(operand.ty);
 620                             adt::is_discr_signed(&l)
 621                         } else {
 622                             operand.ty.is_signed()
 623                         };
 624
 625                         unsafe {
 626                             match (r_t_in, r_t_out) {
 627                                 (CastTy::Int(_), CastTy::Int(_)) => {
 628                                     let s = signed as llvm::Bool;
 629                                     llvm::LLVMConstIntCast(llval, ll_t_out.to_ref(), s)
 630                                 }
 631                                 (CastTy::Int(_), CastTy::Float) => {
 632                                     if signed {
 633                                         llvm::LLVMConstSIToFP(llval, ll_t_out.to_ref())
 634                                     } else {
 635                                         llvm::LLVMConstUIToFP(llval, ll_t_out.to_ref())
 636                                     }
 637                                 }
 638                                 (CastTy::Float, CastTy::Float) => {
 639                                     llvm::LLVMConstFPCast(llval, ll_t_out.to_ref())
 640                                 }
 641                                 (CastTy::Float, CastTy::Int(IntTy::I)) => {
 642                                     llvm::LLVMConstFPToSI(llval, ll_t_out.to_ref())
 643                                 }
 644                                 (CastTy::Float, CastTy::Int(_)) => {
 645                                     llvm::LLVMConstFPToUI(llval, ll_t_out.to_ref())
 646                                 }
 647                                 (CastTy::Ptr(_), CastTy::Ptr(_)) |
 648                                 (CastTy::FnPtr, CastTy::Ptr(_)) |
 649                                 (CastTy::RPtr(_), CastTy::Ptr(_)) => {
 650                                     consts::ptrcast(llval, ll_t_out)
 651                                 }
 652                                 (CastTy::Int(_), CastTy::Ptr(_)) => {
 653                                     llvm::LLVMConstIntToPtr(llval, ll_t_out.to_ref())
 654                                 }
 655                                 (CastTy::Ptr(_), CastTy::Int(_)) |
 656                                 (CastTy::FnPtr, CastTy::Int(_)) => {
 657                                     llvm::LLVMConstPtrToInt(llval, ll_t_out.to_ref())
 658                                 }
 659                                 _ => bug!("unsupported cast: {:?} to {:?}", operand.ty, cast_ty)
 660                             }
 661                         }
 662                     }
 663                     mir::CastKind::Misc => { // Casts from a fat-ptr.
 664                         let ll_cast_ty = type_of::immediate_type_of(self.ccx, cast_ty);
 665                         let ll_from_ty = type_of::immediate_type_of(self.ccx, operand.ty);
 666                         if common::type_is_fat_ptr(self.ccx, operand.ty) {
 667                             let (data_ptr, meta_ptr) = operand.get_fat_ptr();
 668                             if common::type_is_fat_ptr(self.ccx, cast_ty) {
 669                                 let ll_cft = ll_cast_ty.field_types();
 670                                 let ll_fft = ll_from_ty.field_types();
 671                                 let data_cast = consts::ptrcast(data_ptr, ll_cft[0]);
 672                                 assert_eq!(ll_cft[1].kind(), ll_fft[1].kind());
 673                                 C_struct(self.ccx, &[data_cast, meta_ptr], false)
 674                             } else { // cast to thin-ptr
 675                                 // Cast of fat-ptr to thin-ptr is an extraction of data-ptr and
 676                                 // pointer-cast of that pointer to desired pointer type.
 677                                 consts::ptrcast(data_ptr, ll_cast_ty)
 678                             }
 679                         } else {
 680                             bug!("Unexpected non-fat-pointer operand")
 681                         }
 682                     }
 683                 };
 684                 Const::new(val, cast_ty)
 685             }
 686
 687             mir::Rvalue::Ref(_, bk, ref lvalue) => {
 688                 let tr_lvalue = self.const_lvalue(lvalue, span)?;
 689
 690                 let ty = tr_lvalue.ty;
 691                 let ref_ty = tcx.mk_ref(tcx.mk_region(ty::ReErased),
 692                     ty::TypeAndMut { ty: ty, mutbl: bk.to_mutbl_lossy() });
 693
 694                 let base = match tr_lvalue.base {
 695                     Base::Value(llval) => {
 696                         // FIXME: may be wrong for &*(&simd_vec as &fmt::Debug)
 697                         let align = if self.ccx.shared().type_is_sized(ty) {
 698                             type_of::align_of(self.ccx, ty)
 699                         } else {
 700                             self.ccx.tcx().data_layout.pointer_align.abi() as machine::llalign
 701                         };
 702                         if bk == mir::BorrowKind::Mut {
 703                             consts::addr_of_mut(self.ccx, llval, align, "ref_mut")
 704                         } else {
 705                             consts::addr_of(self.ccx, llval, align, "ref")
 706                         }
 707                     }
 708                     Base::Str(llval) |
 709                     Base::Static(llval) => llval
 710                 };
 711
 712                 let ptr = if self.ccx.shared().type_is_sized(ty) {
 713                     base
 714                 } else {
 715                     C_struct(self.ccx, &[base, tr_lvalue.llextra], false)
 716                 };
 717                 Const::new(ptr, ref_ty)
 718             }
 719
 720             mir::Rvalue::Len(ref lvalue) => {
 721                 let tr_lvalue = self.const_lvalue(lvalue, span)?;
 722                 Const::new(tr_lvalue.len(self.ccx), tcx.types.usize)
 723             }
 724
 725             mir::Rvalue::BinaryOp(op, ref lhs, ref rhs) => {
 726                 let lhs = self.const_operand(lhs, span)?;
 727                 let rhs = self.const_operand(rhs, span)?;
 728                 let ty = lhs.ty;
 729                 let binop_ty = op.ty(tcx, lhs.ty, rhs.ty);
 730                 let (lhs, rhs) = (lhs.llval, rhs.llval);
 731                 Const::new(const_scalar_binop(op, lhs, rhs, ty), binop_ty)
 732             }
 733
 734             mir::Rvalue::CheckedBinaryOp(op, ref lhs, ref rhs) => {
 735                 let lhs = self.const_operand(lhs, span)?;
 736                 let rhs = self.const_operand(rhs, span)?;
 737                 let ty = lhs.ty;
 738                 let val_ty = op.ty(tcx, lhs.ty, rhs.ty);
 739                 let binop_ty = tcx.intern_tup(&[val_ty, tcx.types.bool], false);
 740                 let (lhs, rhs) = (lhs.llval, rhs.llval);
 741                 assert!(!ty.is_fp());
 742
 743                 match const_scalar_checked_binop(tcx, op, lhs, rhs, ty) {
 744                     Some((llval, of)) => {
 745                         let llof = C_bool(self.ccx, of);
 746                         Const::new(C_struct(self.ccx, &[llval, llof], false), binop_ty)
 747                     }
 748                     None => {
 749                         span_bug!(span, "{:?} got non-integer operands: {:?} and {:?}",
 750                                   rvalue, Value(lhs), Value(rhs));
 751                     }
 752                 }
 753             }
 754
 755             mir::Rvalue::UnaryOp(op, ref operand) => {
 756                 let operand = self.const_operand(operand, span)?;
 757                 let lloperand = operand.llval;
 758                 let llval = match op {
 759                     mir::UnOp::Not => {
 760                         unsafe {
 761                             llvm::LLVMConstNot(lloperand)
 762                         }
 763                     }
 764                     mir::UnOp::Neg => {
 765                         let is_float = operand.ty.is_fp();
 766                         unsafe {
 767                             if is_float {
 768                                 llvm::LLVMConstFNeg(lloperand)
 769                             } else {
 770                                 llvm::LLVMConstNeg(lloperand)
 771                             }
 772                         }
 773                     }
 774                 };
 775                 Const::new(llval, operand.ty)
 776             }
 777
 778             _ => span_bug!(span, "{:?} in constant", rvalue)
 779         };
 780
 781         debug!("const_rvalue({:?}: {:?} @ {:?}) = {:?}", rvalue, dest_ty, span, val);
 782
 783         Ok(val)
 784     }
 785
 786 }
 787
 788 fn to_const_int(value: ValueRef, t: Ty, tcx: TyCtxt) -> Option<ConstInt> {
 789     match t.sty {
 790         ty::TyInt(int_type) => const_to_opt_u128(value, true)
 791             .and_then(|input| ConstInt::new_signed(input as i128, int_type,
 792                                                    tcx.sess.target.int_type)),
 793         ty::TyUint(uint_type) => const_to_opt_u128(value, false)
 794             .and_then(|input| ConstInt::new_unsigned(input, uint_type,
 795                                                      tcx.sess.target.uint_type)),
 796         _ => None
 797
 798     }
 799 }
 800
 801 pub fn const_scalar_binop(op: mir::BinOp,
 802                           lhs: ValueRef,
 803                           rhs: ValueRef,
 804                           input_ty: Ty) -> ValueRef {
 805     assert!(!input_ty.is_simd());
 806     let is_float = input_ty.is_fp();
 807     let signed = input_ty.is_signed();
 808
 809     unsafe {
 810         match op {
 811             mir::BinOp::Add if is_float => llvm::LLVMConstFAdd(lhs, rhs),
 812             mir::BinOp::Add             => llvm::LLVMConstAdd(lhs, rhs),
 813
 814             mir::BinOp::Sub if is_float => llvm::LLVMConstFSub(lhs, rhs),
 815             mir::BinOp::Sub             => llvm::LLVMConstSub(lhs, rhs),
 816
 817             mir::BinOp::Mul if is_float => llvm::LLVMConstFMul(lhs, rhs),
 818             mir::BinOp::Mul             => llvm::LLVMConstMul(lhs, rhs),
 819
 820             mir::BinOp::Div if is_float => llvm::LLVMConstFDiv(lhs, rhs),
 821             mir::BinOp::Div if signed   => llvm::LLVMConstSDiv(lhs, rhs),
 822             mir::BinOp::Div             => llvm::LLVMConstUDiv(lhs, rhs),
 823
 824             mir::BinOp::Rem if is_float => llvm::LLVMConstFRem(lhs, rhs),
 825             mir::BinOp::Rem if signed   => llvm::LLVMConstSRem(lhs, rhs),
 826             mir::BinOp::Rem             => llvm::LLVMConstURem(lhs, rhs),
 827
 828             mir::BinOp::BitXor => llvm::LLVMConstXor(lhs, rhs),
 829             mir::BinOp::BitAnd => llvm::LLVMConstAnd(lhs, rhs),
 830             mir::BinOp::BitOr  => llvm::LLVMConstOr(lhs, rhs),
 831             mir::BinOp::Shl    => {
 832                 let rhs = base::cast_shift_const_rhs(op.to_hir_binop(), lhs, rhs);
 833                 llvm::LLVMConstShl(lhs, rhs)
 834             }
 835             mir::BinOp::Shr    => {
 836                 let rhs = base::cast_shift_const_rhs(op.to_hir_binop(), lhs, rhs);
 837                 if signed { llvm::LLVMConstAShr(lhs, rhs) }
 838                 else      { llvm::LLVMConstLShr(lhs, rhs) }
 839             }
 840             mir::BinOp::Eq | mir::BinOp::Ne |
 841             mir::BinOp::Lt | mir::BinOp::Le |
 842             mir::BinOp::Gt | mir::BinOp::Ge => {
 843                 if is_float {
 844                     let cmp = base::bin_op_to_fcmp_predicate(op.to_hir_binop());
 845                     llvm::LLVMConstFCmp(cmp, lhs, rhs)
 846                 } else {
 847                     let cmp = base::bin_op_to_icmp_predicate(op.to_hir_binop(),
 848                                                                 signed);
 849                     llvm::LLVMConstICmp(cmp, lhs, rhs)
 850                 }
 851             }
 852         }
 853     }
 854 }
 855
 856 pub fn const_scalar_checked_binop<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
 857                                             op: mir::BinOp,
 858                                             lllhs: ValueRef,
 859                                             llrhs: ValueRef,
 860                                             input_ty: Ty<'tcx>)
 861                                             -> Option<(ValueRef, bool)> {
 862     if let (Some(lhs), Some(rhs)) = (to_const_int(lllhs, input_ty, tcx),
 863                                      to_const_int(llrhs, input_ty, tcx)) {
 864         let result = match op {
 865             mir::BinOp::Add => lhs + rhs,
 866             mir::BinOp::Sub => lhs - rhs,
 867             mir::BinOp::Mul => lhs * rhs,
 868             mir::BinOp::Shl => lhs << rhs,
 869             mir::BinOp::Shr => lhs >> rhs,
 870             _ => {
 871                 bug!("Operator `{:?}` is not a checkable operator", op)
 872             }
 873         };
 874
 875         let of = match result {
 876             Ok(_) => false,
 877             Err(ConstMathErr::Overflow(_)) |
 878             Err(ConstMathErr::ShiftNegative) => true,
 879             Err(err) => {
 880                 bug!("Operator `{:?}` on `{:?}` and `{:?}` errored: {}",
 881                      op, lhs, rhs, err.description());
 882             }
 883         };
 884
 885         Some((const_scalar_binop(op, lllhs, llrhs, input_ty), of))
 886     } else {
 887         None
 888     }
 889 }
 890
 891 impl<'a, 'tcx> MirContext<'a, 'tcx> {
 892     pub fn trans_constant(&mut self,
 893                           bcx: &Builder<'a, 'tcx>,
 894                           constant: &mir::Constant<'tcx>)
 895                           -> Const<'tcx>
 896     {
 897         debug!("trans_constant({:?})", constant);
 898         let ty = self.monomorphize(&constant.ty);
 899         let result = match constant.literal.clone() {
 900             mir::Literal::Item { def_id, substs } => {
 901                 // Shortcut for zero-sized types, including function item
 902                 // types, which would not work with MirConstContext.
 903                 if common::type_is_zero_size(bcx.ccx, ty) {
 904                     let llty = type_of::type_of(bcx.ccx, ty);
 905                     return Const::new(C_null(llty), ty);
 906                 }
 907
 908                 let substs = self.monomorphize(&substs);
 909                 let instance = Instance::new(def_id, substs);
 910                 MirConstContext::trans_def(bcx.ccx, instance, IndexVec::new())
 911             }
 912             mir::Literal::Promoted { index } => {
 913                 let mir = &self.mir.promoted[index];
 914                 MirConstContext::new(bcx.ccx, mir, self.param_substs, IndexVec::new()).trans()
 915             }
 916             mir::Literal::Value { value } => {
 917                 Ok(Const::from_constval(bcx.ccx, value, ty))
 918             }
 919         };
 920
 921         let result = result.unwrap_or_else(|_| {
 922             // We've errored, so we don't have to produce working code.
 923             let llty = type_of::type_of(bcx.ccx, ty);
 924             Const::new(C_undef(llty), ty)
 925         });
 926
 927         debug!("trans_constant({:?}) = {:?}", constant, result);
 928         result
 929     }
 930 }
 931
 932
 933 pub fn trans_static_initializer(ccx: &CrateContext, def_id: DefId)
 934                                 -> Result<ValueRef, ConstEvalErr> {
 935     let instance = Instance::mono(ccx.shared(), def_id);
 936     MirConstContext::trans_def(ccx, instance, IndexVec::new()).map(|c| c.llval)
 937 }
 938
 939 /// Construct a constant value, suitable for initializing a
 940 /// GlobalVariable, given a case and constant values for its fields.
 941 /// Note that this may have a different LLVM type (and different
 942 /// alignment!) from the representation's `type_of`, so it needs a
 943 /// pointer cast before use.
 944 ///
 945 /// The LLVM type system does not directly support unions, and only
 946 /// pointers can be bitcast, so a constant (and, by extension, the
 947 /// GlobalVariable initialized by it) will have a type that can vary
 948 /// depending on which case of an enum it is.
 949 ///
 950 /// To understand the alignment situation, consider `enum E { V64(u64),
 951 /// V32(u32, u32) }` on Windows.  The type has 8-byte alignment to
 952 /// accommodate the u64, but `V32(x, y)` would have LLVM type `{i32,
 953 /// i32, i32}`, which is 4-byte aligned.
 954 ///
 955 /// Currently the returned value has the same size as the type, but
 956 /// this could be changed in the future to avoid allocating unnecessary
 957 /// space after values of shorter-than-maximum cases.
 958 fn trans_const<'a, 'tcx>(
 959     ccx: &CrateContext<'a, 'tcx>,
 960     t: Ty<'tcx>,
 961     kind: &mir::AggregateKind,
 962     vals: &[ValueRef]
 963 ) -> ValueRef {
 964     let l = ccx.layout_of(t);
 965     let dl = &ccx.tcx().data_layout;
 966     let variant_index = match *kind {
 967         mir::AggregateKind::Adt(_, index, _, _) => index,
 968         _ => 0,
 969     };
 970     match *l {
 971         layout::CEnum { discr: d, min, max, .. } => {
 972             let discr = match *kind {
 973                 mir::AggregateKind::Adt(adt_def, _, _, _) => {
 974                     Disr::from(adt_def.variants[variant_index].disr_val)
 975                 },
 976                 _ => Disr(0),
 977             };
 978             assert_eq!(vals.len(), 0);
 979             adt::assert_discr_in_range(Disr(min), Disr(max), discr);
 980             C_integral(Type::from_integer(ccx, d), discr.0, true)
 981         }
 982         layout::General { discr: d, ref variants, .. } => {
 983             let variant = &variants[variant_index];
 984             let lldiscr = C_integral(Type::from_integer(ccx, d), variant_index as u64, true);
 985             let mut vals_with_discr = vec![lldiscr];
 986             vals_with_discr.extend_from_slice(vals);
 987             let mut contents = build_const_struct(ccx, &variant, &vals_with_discr[..]);
 988             let needed_padding = l.size(dl).bytes() - variant.stride().bytes();
 989             if needed_padding > 0 {
 990                 contents.push(padding(ccx, needed_padding));
 991             }
 992             C_struct(ccx, &contents[..], false)
 993         }
 994         layout::UntaggedUnion { ref variants, .. }=> {
 995             assert_eq!(variant_index, 0);
 996             let contents = build_const_union(ccx, variants, vals[0]);
 997             C_struct(ccx, &contents, variants.packed)
 998         }
 999         layout::Univariant { ref variant, .. } => {
1000             assert_eq!(variant_index, 0);
1001             let contents = build_const_struct(ccx, &variant, vals);
1002             C_struct(ccx, &contents[..], variant.packed)
1003         }
1004         layout::Vector { .. } => {
1005             C_vector(vals)
1006         }
1007         layout::RawNullablePointer { nndiscr, .. } => {
1008             let nnty = adt::compute_fields(ccx, t, nndiscr as usize, false)[0];
1009             if variant_index as u64 == nndiscr {
1010                 assert_eq!(vals.len(), 1);
1011                 vals[0]
1012             } else {
1013                 C_null(type_of::sizing_type_of(ccx, nnty))
1014             }
1015         }
1016         layout::StructWrappedNullablePointer { ref nonnull, nndiscr, .. } => {
1017             if variant_index as u64 == nndiscr {
1018                 C_struct(ccx, &build_const_struct(ccx, &nonnull, vals), false)
1019             } else {
1020                 let fields = adt::compute_fields(ccx, t, nndiscr as usize, false);
1021                 let vals = fields.iter().map(|&ty| {
1022                     // Always use null even if it's not the `discrfield`th
1023                     // field; see #8506.
1024                     C_null(type_of::sizing_type_of(ccx, ty))
1025                 }).collect::<Vec<ValueRef>>();
1026                 C_struct(ccx, &build_const_struct(ccx, &nonnull, &vals[..]), false)
1027             }
1028         }
1029         _ => bug!("trans_const: cannot handle type {} repreented as {:#?}", t, l)
1030     }
1031 }
1032
1033 /// Building structs is a little complicated, because we might need to
1034 /// insert padding if a field's value is less aligned than its type.
1035 ///
1036 /// Continuing the example from `trans_const`, a value of type `(u32,
1037 /// E)` should have the `E` at offset 8, but if that field's
1038 /// initializer is 4-byte aligned then simply translating the tuple as
1039 /// a two-element struct will locate it at offset 4, and accesses to it
1040 /// will read the wrong memory.
1041 fn build_const_struct<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1042                                 st: &layout::Struct,
1043                                 vals: &[ValueRef])
1044                                 -> Vec<ValueRef> {
1045     assert_eq!(vals.len(), st.offsets.len());
1046
1047     if vals.len() == 0 {
1048         return Vec::new();
1049     }
1050
1051     // offset of current value
1052     let mut offset = 0;
1053     let mut cfields = Vec::new();
1054     cfields.reserve(st.offsets.len()*2);
1055
1056     let parts = st.field_index_by_increasing_offset().map(|i| {
1057         (&vals[i], st.offsets[i].bytes())
1058     });
1059     for (&val, target_offset) in parts {
1060         if offset < target_offset {
1061             cfields.push(padding(ccx, target_offset - offset));
1062             offset = target_offset;
1063         }
1064         assert!(!is_undef(val));
1065         cfields.push(val);
1066         offset += machine::llsize_of_alloc(ccx, val_ty(val));
1067     }
1068
1069     if offset < st.stride().bytes() {
1070         cfields.push(padding(ccx, st.stride().bytes() - offset));
1071     }
1072
1073     cfields
1074 }
1075
1076 fn build_const_union<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
1077                                un: &layout::Union,
1078                                field_val: ValueRef)
1079                                -> Vec<ValueRef> {
1080     let mut cfields = vec![field_val];
1081
1082     let offset = machine::llsize_of_alloc(ccx, val_ty(field_val));
1083     let size = un.stride().bytes();
1084     if offset != size {
1085         cfields.push(padding(ccx, size - offset));
1086     }
1087
1088     cfields
1089 }
1090
1091 fn padding(ccx: &CrateContext, size: u64) -> ValueRef {
1092     C_undef(Type::array(&Type::i8(ccx), size))
1093 }