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 lib::llvm::{ValueRef, llvm};
  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_str;
  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> {
  37     visitor_val: ValueRef,
  38     visitor_methods: @Vec<@ty::Method> ,
  39     final_bcx: &'a Block<'a>,
  40     tydesc_ty: Type,
  41     bcx: &'a Block<'a>
  42 }
  43
  44 impl<'a> Reflector<'a> {
  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_vstore = ty::VstoreSlice(ty::ReStatic, ());
  58         let str_ty = ty::mk_str(bcx.tcx(), str_vstore);
  59         let scratch = rvalue_scratch_datum(bcx, str_ty, "");
  60         let len = C_uint(bcx.ccx(), s.get().len());
  61         let c_str = PointerCast(bcx, C_cstr(bcx.ccx(), s, false), Type::i8p(bcx.ccx()));
  62         Store(bcx, c_str, GEPi(bcx, scratch.val, [ 0, 0 ]));
  63         Store(bcx, len, GEPi(bcx, scratch.val, [ 0, 1 ]));
  64         scratch.val
  65     }
  66
  67     pub fn c_size_and_align(&mut self, t: ty::t) -> Vec<ValueRef> {
  68         let tr = type_of(self.bcx.ccx(), t);
  69         let s = machine::llsize_of_real(self.bcx.ccx(), tr);
  70         let a = machine::llalign_of_min(self.bcx.ccx(), tr);
  71         return vec!(self.c_uint(s as uint),
  72              self.c_uint(a as uint));
  73     }
  74
  75     pub fn c_tydesc(&mut self, t: ty::t) -> ValueRef {
  76         let bcx = self.bcx;
  77         let static_ti = get_tydesc(bcx.ccx(), t);
  78         glue::lazily_emit_visit_glue(bcx.ccx(), static_ti);
  79         PointerCast(bcx, static_ti.tydesc, self.tydesc_ty.ptr_to())
  80     }
  81
  82     pub fn c_mt(&mut self, mt: &ty::mt) -> Vec<ValueRef> {
  83         vec!(self.c_uint(mt.mutbl as uint),
  84           self.c_tydesc(mt.ty))
  85     }
  86
  87     pub fn visit(&mut self, ty_name: &str, args: &[ValueRef]) {
  88         let fcx = self.bcx.fcx;
  89         let tcx = self.bcx.tcx();
  90         let mth_idx = ty::method_idx(token::str_to_ident("visit_".to_owned() + ty_name),
  91                                      self.visitor_methods.as_slice()).expect(
  92                 format!("couldn't find visit method for {}", ty_name));
  93         let mth_ty =
  94             ty::mk_bare_fn(tcx,
  95                            self.visitor_methods.get(mth_idx).fty.clone());
  96         let v = self.visitor_val;
  97         debug!("passing {} args:", args.len());
  98         let mut bcx = self.bcx;
  99         for (i, a) in args.iter().enumerate() {
 100             debug!("arg {}: {}", i, bcx.val_to_str(*a));
 101         }
 102         let result = unpack_result!(bcx, callee::trans_call_inner(
 103             self.bcx, None, mth_ty,
 104             |bcx, _| meth::trans_trait_callee_from_llval(bcx,
 105                                                          mth_ty,
 106                                                          mth_idx,
 107                                                          v),
 108             ArgVals(args), None));
 109         let result = bool_to_i1(bcx, result);
 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("enter_" + bracket_name, extra);
 120         inner(self);
 121         self.visit("leave_" + bracket_name, extra);
 122     }
 123
 124     pub fn vstore_name_and_extra<M>(&mut self,
 125                                     t: ty::t,
 126                                     vstore: ty::Vstore<M>)
 127                                     -> (~str, Vec<ValueRef> ) {
 128         match vstore {
 129             ty::VstoreFixed(n) => {
 130                 let extra = (vec!(self.c_uint(n))).append(self.c_size_and_align(t).as_slice());
 131                 ("fixed".to_owned(), extra)
 132             }
 133             ty::VstoreSlice(..) => ("slice".to_owned(), Vec::new()),
 134             ty::VstoreUniq => ("uniq".to_owned(), Vec::new()),
 135         }
 136     }
 137
 138     pub fn leaf(&mut self, name: &str) {
 139         self.visit(name, []);
 140     }
 141
 142     // Entrypoint
 143     pub fn visit_ty(&mut self, t: ty::t) {
 144         let bcx = self.bcx;
 145         let tcx = bcx.tcx();
 146         debug!("reflect::visit_ty {}", ty_to_str(bcx.tcx(), t));
 147
 148         match ty::get(t).sty {
 149           ty::ty_bot => self.leaf("bot"),
 150           ty::ty_nil => self.leaf("nil"),
 151           ty::ty_bool => self.leaf("bool"),
 152           ty::ty_char => self.leaf("char"),
 153           ty::ty_int(ast::TyI) => self.leaf("int"),
 154           ty::ty_int(ast::TyI8) => self.leaf("i8"),
 155           ty::ty_int(ast::TyI16) => self.leaf("i16"),
 156           ty::ty_int(ast::TyI32) => self.leaf("i32"),
 157           ty::ty_int(ast::TyI64) => self.leaf("i64"),
 158           ty::ty_uint(ast::TyU) => self.leaf("uint"),
 159           ty::ty_uint(ast::TyU8) => self.leaf("u8"),
 160           ty::ty_uint(ast::TyU16) => self.leaf("u16"),
 161           ty::ty_uint(ast::TyU32) => self.leaf("u32"),
 162           ty::ty_uint(ast::TyU64) => self.leaf("u64"),
 163           ty::ty_float(ast::TyF32) => self.leaf("f32"),
 164           ty::ty_float(ast::TyF64) => self.leaf("f64"),
 165
 166           // Should rename to str_*/vec_*.
 167           ty::ty_str(vst) => {
 168               let (name, extra) = self.vstore_name_and_extra(t, vst);
 169               self.visit("estr_".to_owned() + name, extra.as_slice())
 170           }
 171           ty::ty_vec(ty, vst) => {
 172               let (name, extra) = self.vstore_name_and_extra(t, vst);
 173               let extra = extra.append(self.c_mt(&ty::mt {
 174                   ty: ty,
 175                   mutbl: match vst {
 176                       ty::VstoreSlice(_, m) => m,
 177                       _ => ast::MutImmutable
 178                   }
 179               }).as_slice());
 180               self.visit("evec_".to_owned() + name, extra.as_slice())
 181           }
 182           // Should remove mt from box and uniq.
 183           ty::ty_box(typ) => {
 184               let extra = self.c_mt(&ty::mt {
 185                   ty: typ,
 186                   mutbl: ast::MutImmutable,
 187               });
 188               self.visit("box", extra.as_slice())
 189           }
 190           ty::ty_uniq(typ) => {
 191               let extra = self.c_mt(&ty::mt {
 192                   ty: typ,
 193                   mutbl: ast::MutImmutable,
 194               });
 195               self.visit("uniq", extra.as_slice())
 196           }
 197           ty::ty_ptr(ref mt) => {
 198               let extra = self.c_mt(mt);
 199               self.visit("ptr", extra.as_slice())
 200           }
 201           ty::ty_rptr(_, ref mt) => {
 202               let extra = self.c_mt(mt);
 203               self.visit("rptr", extra.as_slice())
 204           }
 205
 206           ty::ty_tup(ref tys) => {
 207               let extra = (vec!(self.c_uint(tys.len())))
 208                           .append(self.c_size_and_align(t).as_slice());
 209               self.bracketed("tup", extra.as_slice(), |this| {
 210                   for (i, t) in tys.iter().enumerate() {
 211                       let extra = vec!(this.c_uint(i), this.c_tydesc(*t));
 212                       this.visit("tup_field", extra.as_slice());
 213                   }
 214               })
 215           }
 216
 217           // FIXME (#2594): fetch constants out of intrinsic
 218           // FIXME (#4809): visitor should break out bare fns from other fns
 219           ty::ty_closure(ref fty) => {
 220             let pureval = ast_fn_style_constant(fty.fn_style);
 221             let sigilval = match fty.store {
 222                 ty::UniqTraitStore => 2u,
 223                 ty::RegionTraitStore(..) => 4u,
 224             };
 225             let retval = if ty::type_is_bot(fty.sig.output) {0u} else {1u};
 226             let extra = vec!(self.c_uint(pureval),
 227                           self.c_uint(sigilval),
 228                           self.c_uint(fty.sig.inputs.len()),
 229                           self.c_uint(retval));
 230             self.visit("enter_fn", extra.as_slice());
 231             self.visit_sig(retval, &fty.sig);
 232             self.visit("leave_fn", extra.as_slice());
 233           }
 234
 235           // FIXME (#2594): fetch constants out of intrinsic:: for the
 236           // numbers.
 237           ty::ty_bare_fn(ref fty) => {
 238             let pureval = ast_fn_style_constant(fty.fn_style);
 239             let sigilval = 0u;
 240             let retval = if ty::type_is_bot(fty.sig.output) {0u} else {1u};
 241             let extra = vec!(self.c_uint(pureval),
 242                           self.c_uint(sigilval),
 243                           self.c_uint(fty.sig.inputs.len()),
 244                           self.c_uint(retval));
 245             self.visit("enter_fn", extra.as_slice());
 246             self.visit_sig(retval, &fty.sig);
 247             self.visit("leave_fn", extra.as_slice());
 248           }
 249
 250           ty::ty_struct(did, ref substs) => {
 251               let fields = ty::struct_fields(tcx, did, substs);
 252               let mut named_fields = false;
 253               if !fields.is_empty() {
 254                   named_fields = fields.get(0).ident.name !=
 255                       special_idents::unnamed_field.name;
 256               }
 257
 258               let extra = (vec!(
 259                   self.c_slice(token::intern_and_get_ident(ty_to_str(tcx,
 260                                                                      t))),
 261                   self.c_bool(named_fields),
 262                   self.c_uint(fields.len())
 263               )).append(self.c_size_and_align(t).as_slice());
 264               self.bracketed("class", extra.as_slice(), |this| {
 265                   for (i, field) in fields.iter().enumerate() {
 266                       let extra = (vec!(
 267                         this.c_uint(i),
 268                         this.c_slice(token::get_ident(field.ident)),
 269                         this.c_bool(named_fields)
 270                       )).append(this.c_mt(&field.mt).as_slice());
 271                       this.visit("class_field", extra.as_slice());
 272                   }
 273               })
 274           }
 275
 276           // FIXME (#2595): visiting all the variants in turn is probably
 277           // not ideal. It'll work but will get costly on big enums. Maybe
 278           // let the visitor tell us if it wants to visit only a particular
 279           // variant?
 280           ty::ty_enum(did, ref substs) => {
 281             let ccx = bcx.ccx();
 282             let repr = adt::represent_type(bcx.ccx(), t);
 283             let variants = ty::substd_enum_variants(ccx.tcx(), did, substs);
 284             let llptrty = type_of(ccx, t).ptr_to();
 285             let opaquety = ty::get_opaque_ty(ccx.tcx()).unwrap();
 286             let opaqueptrty = ty::mk_ptr(ccx.tcx(), ty::mt { ty: opaquety,
 287                                                            mutbl: ast::MutImmutable });
 288
 289             let make_get_disr = || {
 290                 let sym = mangle_internal_name_by_path_and_seq(
 291                     ast_map::Values([].iter()).chain(None), "get_disr");
 292
 293                 let llfdecl = decl_internal_rust_fn(ccx, false, [opaqueptrty], ty::mk_u64(), sym);
 294                 let arena = TypedArena::new();
 295                 let fcx = new_fn_ctxt(ccx, llfdecl, -1, false,
 296                                       ty::mk_u64(), None, None, &arena);
 297                 init_function(&fcx, false, ty::mk_u64(), None);
 298
 299                 let arg = unsafe {
 300                     //
 301                     // we know the return type of llfdecl is an int here, so
 302                     // no need for a special check to see if the return type
 303                     // is immediate.
 304                     //
 305                     llvm::LLVMGetParam(llfdecl, fcx.arg_pos(0u) as c_uint)
 306                 };
 307                 let bcx = fcx.entry_bcx.borrow().clone().unwrap();
 308                 let arg = BitCast(bcx, arg, llptrty);
 309                 let ret = adt::trans_get_discr(bcx, repr, arg, Some(Type::i64(ccx)));
 310                 Store(bcx, ret, fcx.llretptr.get().unwrap());
 311                 match fcx.llreturn.get() {
 312                     Some(llreturn) => Br(bcx, llreturn),
 313                     None => {}
 314                 };
 315                 finish_fn(&fcx, bcx);
 316                 llfdecl
 317             };
 318
 319             let enum_args = (vec!(self.c_uint(variants.len()), make_get_disr()))
 320                             .append(self.c_size_and_align(t).as_slice());
 321             self.bracketed("enum", enum_args.as_slice(), |this| {
 322                 for (i, v) in variants.iter().enumerate() {
 323                     let name = token::get_ident(v.name);
 324                     let variant_args = [this.c_uint(i),
 325                                          C_u64(ccx, v.disr_val),
 326                                          this.c_uint(v.args.len()),
 327                                          this.c_slice(name)];
 328                     this.bracketed("enum_variant",
 329                                    variant_args,
 330                                    |this| {
 331                         for (j, a) in v.args.iter().enumerate() {
 332                             let bcx = this.bcx;
 333                             let null = C_null(llptrty);
 334                             let ptr = adt::trans_field_ptr(bcx, repr, null, v.disr_val, j);
 335                             let offset = p2i(ccx, ptr);
 336                             let field_args = [this.c_uint(j),
 337                                                offset,
 338                                                this.c_tydesc(*a)];
 339                             this.visit("enum_variant_field",
 340                                        field_args);
 341                         }
 342                     })
 343                 }
 344             })
 345           }
 346
 347           ty::ty_trait(..) => {
 348               let extra = [
 349                   self.c_slice(token::intern_and_get_ident(ty_to_str(tcx, t)))
 350               ];
 351               self.visit("trait", extra);
 352           }
 353
 354           // Miscellaneous extra types
 355           ty::ty_infer(_) => self.leaf("infer"),
 356           ty::ty_err => self.leaf("err"),
 357           ty::ty_param(ref p) => {
 358               let extra = vec!(self.c_uint(p.idx));
 359               self.visit("param", extra.as_slice())
 360           }
 361           ty::ty_self(..) => self.leaf("self")
 362         }
 363     }
 364
 365     pub fn visit_sig(&mut self, retval: uint, sig: &ty::FnSig) {
 366         for (i, arg) in sig.inputs.iter().enumerate() {
 367             let modeval = 5u;   // "by copy"
 368             let extra = vec!(self.c_uint(i),
 369                          self.c_uint(modeval),
 370                          self.c_tydesc(*arg));
 371             self.visit("fn_input", extra.as_slice());
 372         }
 373         let extra = vec!(self.c_uint(retval),
 374                       self.c_bool(sig.variadic),
 375                       self.c_tydesc(sig.output));
 376         self.visit("fn_output", extra.as_slice());
 377     }
 378 }
 379
 380 // Emit a sequence of calls to visit_ty::visit_foo
 381 pub fn emit_calls_to_trait_visit_ty<'a>(
 382                                     bcx: &'a Block<'a>,
 383                                     t: ty::t,
 384                                     visitor_val: ValueRef,
 385                                     visitor_trait_id: DefId)
 386                                     -> &'a Block<'a> {
 387     let fcx = bcx.fcx;
 388     let final = fcx.new_temp_block("final");
 389     let tydesc_ty = ty::get_tydesc_ty(bcx.tcx()).unwrap();
 390     let tydesc_ty = type_of(bcx.ccx(), tydesc_ty);
 391     let mut r = Reflector {
 392         visitor_val: visitor_val,
 393         visitor_methods: ty::trait_methods(bcx.tcx(), visitor_trait_id),
 394         final_bcx: final,
 395         tydesc_ty: tydesc_ty,
 396         bcx: bcx
 397     };
 398     r.visit_ty(t);
 399     Br(r.bcx, final.llbb);
 400     return final;
 401 }
 402
 403 pub fn ast_fn_style_constant(fn_style: ast::FnStyle) -> uint {
 404     match fn_style {
 405         ast::UnsafeFn => 1u,
 406         ast::NormalFn => 2u,
 407         ast::ExternFn => 3u
 408     }
 409 }