src/librustc/middle/trans/reflect.rs

   1 // Copyright 2012 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 back::link::mangle_internal_name_by_path_and_seq;
  12 use llvm::{ValueRef, get_param};
  13 use middle::trans::adt;
  14 use middle::trans::base::*;
  15 use middle::trans::build::*;
  16 use middle::trans::callee::ArgVals;
  17 use middle::trans::callee;
  18 use middle::trans::common::*;
  19 use middle::trans::datum::*;
  20 use middle::trans::glue;
  21 use middle::trans::machine;
  22 use middle::trans::meth;
  23 use middle::trans::type_::Type;
  24 use middle::trans::type_of::*;
  25 use middle::ty;
  26 use util::ppaux::ty_to_string;
  27
  28 use arena::TypedArena;
  29 use libc::c_uint;
  30 use syntax::ast::DefId;
  31 use syntax::ast;
  32 use syntax::ast_map;
  33 use syntax::parse::token::{InternedString, special_idents};
  34 use syntax::parse::token;
  35
  36 pub struct Reflector<'a, 'b> {
  37     visitor_val: ValueRef,
  38     visitor_items: &'a [ty::ImplOrTraitItem],
  39     final_bcx: &'b Block<'b>,
  40     tydesc_ty: Type,
  41     bcx: &'b Block<'b>
  42 }
  43
  44 impl<'a, 'b> Reflector<'a, 'b> {
  45     pub fn c_uint(&mut self, u: uint) -> ValueRef {
  46         C_uint(self.bcx.ccx(), u)
  47     }
  48
  49     pub fn c_bool(&mut self, b: bool) -> ValueRef {
  50         C_bool(self.bcx.ccx(), b)
  51     }
  52
  53     pub fn c_slice(&mut self, s: InternedString) -> ValueRef {
  54         // We're careful to not use first class aggregates here because that
  55         // will kick us off fast isel. (Issue #4352.)
  56         let bcx = self.bcx;
  57         let str_ty = ty::mk_str_slice(bcx.tcx(), ty::ReStatic, ast::MutImmutable);
  58         let scratch = rvalue_scratch_datum(bcx, str_ty, "");
  59         let len = C_uint(bcx.ccx(), s.get().len());
  60         let c_str = PointerCast(bcx, C_cstr(bcx.ccx(), s, false), Type::i8p(bcx.ccx()));
  61         Store(bcx, c_str, GEPi(bcx, scratch.val, [ 0, 0 ]));
  62         Store(bcx, len, GEPi(bcx, scratch.val, [ 0, 1 ]));
  63         scratch.val
  64     }
  65
  66     pub fn c_size_and_align(&mut self, t: ty::t) -> Vec<ValueRef> {
  67         let tr = type_of(self.bcx.ccx(), t);
  68         let s = machine::llsize_of_real(self.bcx.ccx(), tr);
  69         let a = machine::llalign_of_min(self.bcx.ccx(), tr);
  70         return vec!(self.c_uint(s as uint),
  71              self.c_uint(a as uint));
  72     }
  73
  74     pub fn c_tydesc(&mut self, t: ty::t) -> ValueRef {
  75         let bcx = self.bcx;
  76         let static_ti = get_tydesc(bcx.ccx(), t);
  77         glue::lazily_emit_visit_glue(bcx.ccx(), &*static_ti);
  78         PointerCast(bcx, static_ti.tydesc, self.tydesc_ty.ptr_to())
  79     }
  80
  81     pub fn c_mt(&mut self, mt: &ty::mt) -> Vec<ValueRef> {
  82         vec!(self.c_uint(mt.mutbl as uint),
  83           self.c_tydesc(mt.ty))
  84     }
  85
  86     pub fn visit(&mut self, ty_name: &str, args: &[ValueRef]) {
  87         let fcx = self.bcx.fcx;
  88         let tcx = self.bcx.tcx();
  89         let mth_idx = ty::impl_or_trait_item_idx(token::str_to_ident(format!(
  90                         "visit_{}", ty_name).as_slice()),
  91                                      self.visitor_items.as_slice()).expect(
  92                 format!("couldn't find visit method for {}", ty_name).as_slice());
  93         let method = match self.visitor_items[mth_idx] {
  94             ty::MethodTraitItem(ref method) => (*method).clone(),
  95         };
  96         let mth_ty = ty::mk_bare_fn(tcx, method.fty.clone());
  97         let v = self.visitor_val;
  98         debug!("passing {} args:", args.len());
  99         let mut bcx = self.bcx;
 100         for (i, a) in args.iter().enumerate() {
 101             debug!("arg {}: {}", i, bcx.val_to_string(*a));
 102         }
 103         let result = unpack_result!(bcx, callee::trans_call_inner(
 104             self.bcx, None, mth_ty,
 105             |bcx, _| meth::trans_trait_callee_from_llval(bcx,
 106                                                          mth_ty,
 107                                                          mth_idx,
 108                                                          v),
 109             ArgVals(args), None));
 110         let next_bcx = fcx.new_temp_block("next");
 111         CondBr(bcx, result, next_bcx.llbb, self.final_bcx.llbb);
 112         self.bcx = next_bcx
 113     }
 114
 115     pub fn bracketed(&mut self,
 116                      bracket_name: &str,
 117                      extra: &[ValueRef],
 118                      inner: |&mut Reflector|) {
 119         self.visit(format!("enter_{}", bracket_name).as_slice(), extra);
 120         inner(self);
 121         self.visit(format!("leave_{}", bracket_name).as_slice(), extra);
 122     }
 123
 124     pub fn leaf(&mut self, name: &str) {
 125         self.visit(name, []);
 126     }
 127
 128     // Entrypoint
 129     pub fn visit_ty(&mut self, t: ty::t) {
 130         let bcx = self.bcx;
 131         let tcx = bcx.tcx();
 132         debug!("reflect::visit_ty {}", ty_to_string(bcx.tcx(), t));
 133
 134         match ty::get(t).sty {
 135           ty::ty_bot => self.leaf("bot"),
 136           ty::ty_nil => self.leaf("nil"),
 137           ty::ty_bool => self.leaf("bool"),
 138           ty::ty_char => self.leaf("char"),
 139           ty::ty_int(ast::TyI) => self.leaf("int"),
 140           ty::ty_int(ast::TyI8) => self.leaf("i8"),
 141           ty::ty_int(ast::TyI16) => self.leaf("i16"),
 142           ty::ty_int(ast::TyI32) => self.leaf("i32"),
 143           ty::ty_int(ast::TyI64) => self.leaf("i64"),
 144           ty::ty_uint(ast::TyU) => self.leaf("uint"),
 145           ty::ty_uint(ast::TyU8) => self.leaf("u8"),
 146           ty::ty_uint(ast::TyU16) => self.leaf("u16"),
 147           ty::ty_uint(ast::TyU32) => self.leaf("u32"),
 148           ty::ty_uint(ast::TyU64) => self.leaf("u64"),
 149           ty::ty_float(ast::TyF32) => self.leaf("f32"),
 150           ty::ty_float(ast::TyF64) => self.leaf("f64"),
 151
 152           // Should rename to vec_*.
 153           ty::ty_vec(ref mt, Some(sz)) => {
 154               let extra = (vec!(self.c_uint(sz))).append(self.c_size_and_align(t).as_slice());
 155               let extra = extra.append(self.c_mt(mt).as_slice());
 156               self.visit("evec_fixed", extra.as_slice())
 157           }
 158           ty::ty_vec(..) | ty::ty_str | ty::ty_trait(..) => fail!("unexpected unsized type"),
 159           // Should remove mt from box and uniq.
 160           ty::ty_box(typ) => {
 161               let extra = self.c_mt(&ty::mt {
 162                   ty: typ,
 163                   mutbl: ast::MutImmutable,
 164               });
 165               self.visit("box", extra.as_slice())
 166           }
 167           ty::ty_uniq(typ) => {
 168               match ty::get(typ).sty {
 169                   ty::ty_vec(ref mt, None) => {
 170                       let extra = Vec::new();
 171                       let extra = extra.append(self.c_mt(mt).as_slice());
 172                       self.visit("evec_uniq", extra.as_slice())
 173                   }
 174                   ty::ty_str => self.visit("estr_uniq", &[]),
 175                   ty::ty_trait(..) => {
 176                       let extra = [
 177                           self.c_slice(token::intern_and_get_ident(
 178                                   ty_to_string(tcx, t).as_slice()))
 179                       ];
 180                       self.visit("trait", extra);
 181                   }
 182                   _ => {
 183                       let extra = self.c_mt(&ty::mt {
 184                           ty: typ,
 185                           mutbl: ast::MutImmutable,
 186                       });
 187                       self.visit("uniq", extra.as_slice())
 188                   }
 189               }
 190           }
 191           ty::ty_ptr(ref mt) => {
 192               let extra = self.c_mt(mt);
 193               self.visit("ptr", extra.as_slice())
 194           }
 195           ty::ty_rptr(_, ref mt) => {
 196               match ty::get(mt.ty).sty {
 197                   ty::ty_vec(ref mt, None) => {
 198                       let (name, extra) = ("slice".to_string(), Vec::new());
 199                       let extra = extra.append(self.c_mt(mt).as_slice());
 200                       self.visit(format!("evec_{}", name).as_slice(),
 201                                  extra.as_slice())
 202                   }
 203                   ty::ty_str => self.visit("estr_slice", &[]),
 204                   ty::ty_trait(..) => {
 205                       let extra = [
 206                           self.c_slice(token::intern_and_get_ident(
 207                                   ty_to_string(tcx, t).as_slice()))
 208                       ];
 209                       self.visit("trait", extra);
 210                   }
 211                   _ => {
 212                       let extra = self.c_mt(mt);
 213                       self.visit("rptr", extra.as_slice())
 214                   }
 215               }
 216           }
 217
 218           ty::ty_tup(ref tys) => {
 219               let extra = (vec!(self.c_uint(tys.len())))
 220                           .append(self.c_size_and_align(t).as_slice());
 221               self.bracketed("tup", extra.as_slice(), |this| {
 222                   for (i, t) in tys.iter().enumerate() {
 223                       let extra = vec!(this.c_uint(i), this.c_tydesc(*t));
 224                       this.visit("tup_field", extra.as_slice());
 225                   }
 226               })
 227           }
 228
 229           // FIXME (#2594): fetch constants out of intrinsic
 230           // FIXME (#4809): visitor should break out bare fns from other fns
 231           ty::ty_closure(ref fty) => {
 232             let pureval = ast_fn_style_constant(fty.fn_style);
 233             let sigilval = match fty.store {
 234                 ty::UniqTraitStore => 2u,
 235                 ty::RegionTraitStore(..) => 4u,
 236             };
 237             let retval = if ty::type_is_bot(fty.sig.output) {0u} else {1u};
 238             let extra = vec!(self.c_uint(pureval),
 239                           self.c_uint(sigilval),
 240                           self.c_uint(fty.sig.inputs.len()),
 241                           self.c_uint(retval));
 242             self.visit("enter_fn", extra.as_slice());
 243             self.visit_sig(retval, &fty.sig);
 244             self.visit("leave_fn", extra.as_slice());
 245           }
 246
 247           // FIXME (#2594): fetch constants out of intrinsic:: for the
 248           // numbers.
 249           ty::ty_bare_fn(ref fty) => {
 250             let pureval = ast_fn_style_constant(fty.fn_style);
 251             let sigilval = 0u;
 252             let retval = if ty::type_is_bot(fty.sig.output) {0u} else {1u};
 253             let extra = vec!(self.c_uint(pureval),
 254                           self.c_uint(sigilval),
 255                           self.c_uint(fty.sig.inputs.len()),
 256                           self.c_uint(retval));
 257             self.visit("enter_fn", extra.as_slice());
 258             self.visit_sig(retval, &fty.sig);
 259             self.visit("leave_fn", extra.as_slice());
 260           }
 261
 262           ty::ty_struct(did, ref substs) => {
 263               let fields = ty::struct_fields(tcx, did, substs);
 264               let mut named_fields = false;
 265               if !fields.is_empty() {
 266                   named_fields = fields.get(0).ident.name !=
 267                       special_idents::unnamed_field.name;
 268               }
 269
 270               let extra = (vec!(
 271                   self.c_slice(
 272                       token::intern_and_get_ident(ty_to_string(tcx,
 273                                                             t).as_slice())),
 274                   self.c_bool(named_fields),
 275                   self.c_uint(fields.len())
 276               )).append(self.c_size_and_align(t).as_slice());
 277               self.bracketed("class", extra.as_slice(), |this| {
 278                   for (i, field) in fields.iter().enumerate() {
 279                       let extra = (vec!(
 280                         this.c_uint(i),
 281                         this.c_slice(token::get_ident(field.ident)),
 282                         this.c_bool(named_fields)
 283                       )).append(this.c_mt(&field.mt).as_slice());
 284                       this.visit("class_field", extra.as_slice());
 285                   }
 286               })
 287           }
 288
 289           // FIXME (#2595): visiting all the variants in turn is probably
 290           // not ideal. It'll work but will get costly on big enums. Maybe
 291           // let the visitor tell us if it wants to visit only a particular
 292           // variant?
 293           ty::ty_enum(did, ref substs) => {
 294             let ccx = bcx.ccx();
 295             let repr = adt::represent_type(bcx.ccx(), t);
 296             let variants = ty::substd_enum_variants(ccx.tcx(), did, substs);
 297             let llptrty = type_of(ccx, t).ptr_to();
 298             let opaquety = ty::get_opaque_ty(ccx.tcx()).unwrap();
 299             let opaqueptrty = ty::mk_ptr(ccx.tcx(), ty::mt { ty: opaquety,
 300                                                            mutbl: ast::MutImmutable });
 301
 302             let make_get_disr = || {
 303                 let sym = mangle_internal_name_by_path_and_seq(
 304                     ast_map::Values([].iter()).chain(None), "get_disr");
 305
 306                 let fn_ty = ty::mk_ctor_fn(&ccx.tcx, ast::DUMMY_NODE_ID,
 307                                            [opaqueptrty], ty::mk_u64());
 308                 let llfdecl = decl_internal_rust_fn(ccx,
 309                                                     fn_ty,
 310                                                     sym.as_slice());
 311                 let arena = TypedArena::new();
 312                 let empty_param_substs = param_substs::empty();
 313                 let fcx = new_fn_ctxt(ccx, llfdecl, ast::DUMMY_NODE_ID, false,
 314                                       ty::mk_u64(), &empty_param_substs,
 315                                       None, &arena);
 316                 let bcx = init_function(&fcx, false, ty::mk_u64());
 317
 318                 // we know the return type of llfdecl is an int here, so
 319                 // no need for a special check to see if the return type
 320                 // is immediate.
 321                 let arg = get_param(llfdecl, fcx.arg_pos(0u) as c_uint);
 322                 let arg = BitCast(bcx, arg, llptrty);
 323                 let ret = adt::trans_get_discr(bcx, &*repr, arg, Some(Type::i64(ccx)));
 324                 assert!(!fcx.needs_ret_allocas);
 325                 let ret_slot = fcx.get_ret_slot(bcx, ty::mk_u64(), "ret_slot");
 326                 Store(bcx, ret, ret_slot);
 327                 match fcx.llreturn.get() {
 328                     Some(llreturn) => Br(bcx, llreturn),
 329                     None => {}
 330                 };
 331                 finish_fn(&fcx, bcx, ty::mk_u64());
 332                 llfdecl
 333             };
 334
 335             let enum_args = (vec!(self.c_uint(variants.len()), make_get_disr()))
 336                             .append(self.c_size_and_align(t).as_slice());
 337             self.bracketed("enum", enum_args.as_slice(), |this| {
 338                 for (i, v) in variants.iter().enumerate() {
 339                     let name = token::get_ident(v.name);
 340                     let variant_args = [this.c_uint(i),
 341                                          C_u64(ccx, v.disr_val),
 342                                          this.c_uint(v.args.len()),
 343                                          this.c_slice(name)];
 344                     this.bracketed("enum_variant",
 345                                    variant_args,
 346                                    |this| {
 347                         for (j, a) in v.args.iter().enumerate() {
 348                             let bcx = this.bcx;
 349                             let null = C_null(llptrty);
 350                             let ptr = adt::trans_field_ptr(bcx, &*repr, null, v.disr_val, j);
 351                             let offset = p2i(ccx, ptr);
 352                             let field_args = [this.c_uint(j),
 353                                                offset,
 354                                                this.c_tydesc(*a)];
 355                             this.visit("enum_variant_field",
 356                                        field_args);
 357                         }
 358                     })
 359                 }
 360             })
 361           }
 362
 363           // Miscellaneous extra types
 364           ty::ty_infer(_) => self.leaf("infer"),
 365           ty::ty_err => self.leaf("err"),
 366           ty::ty_unboxed_closure(..) => self.leaf("err"),
 367           ty::ty_param(ref p) => {
 368               let extra = vec!(self.c_uint(p.idx));
 369               self.visit("param", extra.as_slice())
 370           }
 371         }
 372     }
 373
 374     pub fn visit_sig(&mut self, retval: uint, sig: &ty::FnSig) {
 375         for (i, arg) in sig.inputs.iter().enumerate() {
 376             let modeval = 5u;   // "by copy"
 377             let extra = vec!(self.c_uint(i),
 378                          self.c_uint(modeval),
 379                          self.c_tydesc(*arg));
 380             self.visit("fn_input", extra.as_slice());
 381         }
 382         let extra = vec!(self.c_uint(retval),
 383                       self.c_bool(sig.variadic),
 384                       self.c_tydesc(sig.output));
 385         self.visit("fn_output", extra.as_slice());
 386     }
 387 }
 388
 389 // Emit a sequence of calls to visit_ty::visit_foo
 390 pub fn emit_calls_to_trait_visit_ty<'a>(
 391                                     bcx: &'a Block<'a>,
 392                                     t: ty::t,
 393                                     visitor_val: ValueRef,
 394                                     visitor_trait_id: DefId)
 395                                     -> &'a Block<'a> {
 396     let fcx = bcx.fcx;
 397     let final = fcx.new_temp_block("final");
 398     let tydesc_ty = ty::get_tydesc_ty(bcx.tcx()).unwrap();
 399     let tydesc_ty = type_of(bcx.ccx(), tydesc_ty);
 400     let visitor_items = ty::trait_items(bcx.tcx(), visitor_trait_id);
 401     let mut r = Reflector {
 402         visitor_val: visitor_val,
 403         visitor_items: visitor_items.as_slice(),
 404         final_bcx: final,
 405         tydesc_ty: tydesc_ty,
 406         bcx: bcx
 407     };
 408     r.visit_ty(t);
 409     Br(r.bcx, final.llbb);
 410     return final;
 411 }
 412
 413 pub fn ast_fn_style_constant(fn_style: ast::FnStyle) -> uint {
 414     match fn_style {
 415         ast::UnsafeFn => 1u,
 416         ast::NormalFn => 2u,
 417     }
 418 }