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.
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.
14 use lib::llvm::ValueRef;
16 use metadata::csearch;
17 use middle::trans::base::*;
18 use middle::trans::build::*;
19 use middle::trans::callee::*;
20 use middle::trans::callee;
21 use middle::trans::cleanup;
22 use middle::trans::common::*;
23 use middle::trans::datum::*;
24 use middle::trans::expr::{SaveIn, Ignore};
25 use middle::trans::expr;
26 use middle::trans::glue;
27 use middle::trans::monomorphize;
28 use middle::trans::type_::Type;
29 use middle::trans::type_of::*;
32 use middle::typeck::MethodCall;
33 use util::common::indenter;
34 use util::ppaux::Repr;
36 use std::c_str::ToCStr;
37 use syntax::abi::Rust;
38 use syntax::parse::token;
39 use syntax::{ast, ast_map, visit};
42 The main "translation" pass for methods. Generates code
43 for non-monomorphized methods only. Other methods will
44 be generated once they are invoked with specific type parameters,
45 see `trans::base::lval_static_fn()` or `trans::base::monomorphic_fn()`.
47 pub fn trans_impl(ccx: &CrateContext,
49 methods: &[@ast::Method],
50 generics: &ast::Generics,
52 let _icx = push_ctxt("meth::trans_impl");
55 debug!("trans_impl(name={}, id={:?})", name.repr(tcx), id);
57 // Both here and below with generic methods, be sure to recurse and look for
58 // items that we need to translate.
59 if !generics.ty_params.is_empty() {
60 let mut v = TransItemVisitor{ ccx: ccx };
61 for method in methods.iter() {
62 visit::walk_method_helper(&mut v, *method, ());
66 for method in methods.iter() {
67 if method.generics.ty_params.len() == 0u {
68 let llfn = get_item_val(ccx, method.id);
69 trans_fn(ccx, method.decl, method.body,
70 llfn, None, method.id, []);
72 let mut v = TransItemVisitor{ ccx: ccx };
73 visit::walk_method_helper(&mut v, *method, ());
78 pub fn trans_method_callee<'a>(
80 method_call: MethodCall,
81 self_expr: Option<&ast::Expr>,
82 arg_cleanup_scope: cleanup::ScopeId)
84 let _icx = push_ctxt("meth::trans_method_callee");
86 let (origin, method_ty) = match bcx.tcx().method_map
87 .borrow().find(&method_call) {
89 debug!("trans_method_callee({:?}, method={})",
90 method_call, method.repr(bcx.tcx()));
91 (method.origin, method.ty)
94 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
95 "method call expr wasn't in method map")
100 typeck::MethodStatic(did) => {
103 data: Fn(callee::trans_fn_ref(bcx, did, MethodCall(method_call)))
106 typeck::MethodParam(typeck::MethodParam {
112 match bcx.fcx.param_substs {
114 ty::populate_implementations_for_trait_if_necessary(
118 let vtbl = find_vtable(bcx.tcx(), substs, p, b);
119 trans_monomorphized_callee(bcx, method_call,
122 // how to get rid of this?
123 None => fail!("trans_method_callee: missing param_substs")
127 typeck::MethodObject(ref mt) => {
128 let self_expr = match self_expr {
129 Some(self_expr) => self_expr,
131 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
132 "self expr wasn't provided for trait object \
133 callee (trying to call overloaded op?)")
136 trans_trait_callee(bcx,
137 monomorphize_type(bcx, method_ty),
145 pub fn trans_static_method_callee(bcx: &Block,
146 method_id: ast::DefId,
147 trait_id: ast::DefId,
148 expr_id: ast::NodeId)
150 let _icx = push_ctxt("meth::trans_static_method_callee");
153 debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
156 ty::item_path_str(bcx.tcx(), trait_id),
158 let _indenter = indenter();
160 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
162 // When we translate a static fn defined in a trait like:
164 // trait<T1...Tn> Trait {
165 // fn foo<M1...Mn>(...) {...}
168 // this winds up being translated as something like:
170 // fn foo<T1...Tn,self: Trait<T1...Tn>,M1...Mn>(...) {...}
172 // So when we see a call to this function foo, we have to figure
173 // out which impl the `Trait<T1...Tn>` bound on the type `self` was
175 let bound_index = ty::lookup_trait_def(bcx.tcx(), trait_id).
176 generics.type_param_defs().len();
178 let mname = if method_id.krate == ast::LOCAL_CRATE {
179 match bcx.tcx().map.get(method_id.node) {
180 ast_map::NodeTraitMethod(method) => {
181 let ident = match *method {
182 ast::Required(ref m) => m.ident,
183 ast::Provided(ref m) => m.ident
187 _ => fail!("callee is not a trait method")
190 csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
192 debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
193 name={}", method_id, expr_id, token::get_name(mname));
195 let vtable_key = MethodCall::expr(expr_id);
196 let vtbls = resolve_vtables_in_fn_ctxt(bcx.fcx, ccx.tcx.vtable_map.borrow()
197 .get(&vtable_key).as_slice());
199 match vtbls.move_iter().nth(bound_index).unwrap().move_iter().nth(0).unwrap() {
200 typeck::vtable_static(impl_did, rcvr_substs, rcvr_origins) => {
201 assert!(rcvr_substs.iter().all(|t| !ty::type_needs_infer(*t)));
203 let mth_id = method_with_name(ccx, impl_did, mname);
204 let (callee_substs, callee_origins) =
205 combine_impl_and_methods_tps(
206 bcx, mth_id, ExprId(expr_id),
207 rcvr_substs, rcvr_origins);
209 let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
211 Some(callee_origins));
213 let callee_ty = node_id_type(bcx, expr_id);
214 let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
215 PointerCast(bcx, llfn, llty)
218 fail!("vtable_param left in monomorphized \
219 function's vtable substs");
224 fn method_with_name(ccx: &CrateContext,
226 name: ast::Name) -> ast::DefId {
227 match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
232 let methods = ccx.tcx.impl_methods.borrow();
233 let methods = methods.find(&impl_id)
234 .expect("could not find impl while translating");
235 let meth_did = methods.iter().find(|&did| ty::method(&ccx.tcx, *did).ident.name == name)
236 .expect("could not find method while translating");
238 ccx.impl_method_cache.borrow_mut().insert((impl_id, name), *meth_did);
242 fn trans_monomorphized_callee<'a>(bcx: &'a Block<'a>,
243 method_call: MethodCall,
244 trait_id: ast::DefId,
246 vtbl: typeck::vtable_origin)
248 let _icx = push_ctxt("meth::trans_monomorphized_callee");
250 typeck::vtable_static(impl_did, rcvr_substs, rcvr_origins) => {
252 let mname = ty::trait_method(ccx.tcx(), trait_id, n_method).ident;
253 let mth_id = method_with_name(bcx.ccx(), impl_did, mname.name);
255 // create a concatenated set of substitutions which includes
256 // those from the impl and those from the method:
257 let (callee_substs, callee_origins) =
258 combine_impl_and_methods_tps(
259 bcx, mth_id, MethodCall(method_call),
260 rcvr_substs, rcvr_origins);
262 // translate the function
263 let llfn = trans_fn_ref_with_vtables(bcx,
265 MethodCall(method_call),
267 Some(callee_origins));
269 Callee { bcx: bcx, data: Fn(llfn) }
271 typeck::vtable_param(..) => {
272 fail!("vtable_param left in monomorphized function's vtable substs");
277 fn combine_impl_and_methods_tps(bcx: &Block,
279 node: ExprOrMethodCall,
280 rcvr_substs: Vec<ty::t>,
281 rcvr_origins: typeck::vtable_res)
282 -> (Vec<ty::t>, typeck::vtable_res) {
285 * Creates a concatenated set of substitutions which includes
286 * those from the impl and those from the method. This are
287 * some subtle complications here. Statically, we have a list
288 * of type parameters like `[T0, T1, T2, M1, M2, M3]` where
289 * `Tn` are type parameters that appear on the receiver. For
290 * example, if the receiver is a method parameter `A` with a
291 * bound like `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
293 * The weird part is that the type `A` might now be bound to
294 * any other type, such as `foo<X>`. In that case, the vector
295 * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is
296 * to slice off the method type parameters and append them to
297 * the type parameters from the type that the receiver is
301 let method = ty::method(ccx.tcx(), mth_did);
302 let n_m_tps = method.generics.type_param_defs().len();
303 let node_substs = node_id_type_params(bcx, node);
304 debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
305 debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
306 let mut ty_substs = rcvr_substs;
308 let start = node_substs.len() - n_m_tps;
309 ty_substs.extend(node_substs.move_iter().skip(start));
311 debug!("n_m_tps={:?}", n_m_tps);
312 debug!("ty_substs={:?}", ty_substs.repr(ccx.tcx()));
315 // Now, do the same work for the vtables. The vtables might not
316 // exist, in which case we need to make them.
317 let vtable_key = match node {
318 ExprId(id) => MethodCall::expr(id),
319 MethodCall(method_call) => method_call
321 let mut vtables = rcvr_origins;
322 match node_vtables(bcx, vtable_key) {
324 let start = vt.len() - n_m_tps;
325 vtables.extend(vt.move_iter().skip(start));
328 vtables.extend(range(0, n_m_tps).map(
329 |_| -> typeck::vtable_param_res {
339 fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
342 self_expr: &ast::Expr,
343 arg_cleanup_scope: cleanup::ScopeId)
346 * Create a method callee where the method is coming from a trait
347 * object (e.g., Box<Trait> type). In this case, we must pull the fn
348 * pointer out of the vtable that is packaged up with the object.
349 * Objects are represented as a pair, so we first evaluate the self
350 * expression and then extract the self data and vtable out of the
354 let _icx = push_ctxt("meth::trans_trait_callee");
357 // Translate self_datum and take ownership of the value by
358 // converting to an rvalue.
359 let self_datum = unpack_datum!(
360 bcx, expr::trans(bcx, self_expr));
362 let llval = if ty::type_needs_drop(bcx.tcx(), self_datum.ty) {
363 let self_datum = unpack_datum!(
364 bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
366 // Convert to by-ref since `trans_trait_callee_from_llval` wants it
368 let self_datum = unpack_datum!(
369 bcx, self_datum.to_ref_datum(bcx));
371 // Arrange cleanup in case something should go wrong before the
372 // actual call occurs.
373 self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
375 // We don't have to do anything about cleanups for &Trait and &mut Trait.
376 assert!(self_datum.kind.is_by_ref());
380 trans_trait_callee_from_llval(bcx, method_ty, n_method, llval)
383 pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
389 * Same as `trans_trait_callee()` above, except that it is given
390 * a by-ref pointer to the object pair.
393 let _icx = push_ctxt("meth::trans_trait_callee");
396 // Load the data pointer from the object.
397 debug!("(translating trait callee) loading second index from pair");
398 let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
399 let llbox = Load(bcx, llboxptr);
400 let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
402 // Load the function from the vtable and cast it to the expected type.
403 debug!("(translating trait callee) loading method");
404 // Replace the self type (&Self or Box<Self>) with an opaque pointer.
405 let llcallee_ty = match ty::get(callee_ty).sty {
406 ty::ty_bare_fn(ref f) if f.abi == Rust => {
407 type_of_rust_fn(ccx, true, f.sig.inputs.slice_from(1), f.sig.output)
410 ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
413 let llvtable = Load(bcx,
416 [0u, abi::trt_field_vtable]),
417 Type::vtable(ccx).ptr_to().ptr_to()));
418 let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1]));
419 let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
423 data: TraitMethod(MethodData {
430 /// Creates a returns a dynamic vtable for the given type and vtable origin.
431 /// This is used only for objects.
432 fn get_vtable(bcx: &Block,
434 origins: typeck::vtable_param_res)
437 let _icx = push_ctxt("meth::get_vtable");
440 let hash_id = (self_ty, monomorphize::make_vtable_id(ccx, origins.get(0)));
441 match ccx.vtables.borrow().find(&hash_id) {
442 Some(&val) => { return val }
446 // Not in the cache. Actually build it.
447 let methods = origins.move_iter().flat_map(|origin| {
449 typeck::vtable_static(id, substs, sub_vtables) => {
450 emit_vtable_methods(bcx, id, substs, sub_vtables).move_iter()
452 _ => ccx.sess().bug("get_vtable: expected a static origin"),
456 // Generate a destructor for the vtable.
457 let drop_glue = glue::get_drop_glue(ccx, self_ty);
458 let vtable = make_vtable(ccx, drop_glue, methods);
460 ccx.vtables.borrow_mut().insert(hash_id, vtable);
464 /// Helper function to declare and initialize the vtable.
465 pub fn make_vtable<I: Iterator<ValueRef>>(ccx: &CrateContext,
469 let _icx = push_ctxt("meth::make_vtable");
471 let components: Vec<_> = Some(drop_glue).move_iter().chain(ptrs).collect();
474 let tbl = C_struct(ccx, components.as_slice(), false);
475 let sym = token::gensym("vtable");
476 let vt_gvar = format!("vtable{}", sym).with_c_str(|buf| {
477 llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
479 llvm::LLVMSetInitializer(vt_gvar, tbl);
480 llvm::LLVMSetGlobalConstant(vt_gvar, lib::llvm::True);
481 lib::llvm::SetLinkage(vt_gvar, lib::llvm::InternalLinkage);
486 fn emit_vtable_methods(bcx: &Block,
489 vtables: typeck::vtable_res)
494 let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
495 Some(t_id) => t_id.def_id,
496 None => ccx.sess().bug("make_impl_vtable: don't know how to \
497 make a vtable for a type impl!")
500 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trt_id);
502 let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
503 trait_method_def_ids.iter().map(|method_def_id| {
504 let ident = ty::method(tcx, *method_def_id).ident;
505 // The substitutions we have are on the impl, so we grab
506 // the method type from the impl to substitute into.
507 let m_id = method_with_name(ccx, impl_id, ident.name);
508 let m = ty::method(tcx, m_id);
509 debug!("(making impl vtable) emitting method {} at subst {}",
512 if m.generics.has_type_params() ||
513 ty::type_has_self(ty::mk_bare_fn(tcx, m.fty.clone())) {
514 debug!("(making impl vtable) method has self or type params: {}",
515 token::get_ident(ident));
516 C_null(Type::nil(ccx).ptr_to())
518 trans_fn_ref_with_vtables(bcx, m_id, ExprId(0),
519 substs.clone(), Some(vtables.clone()))
524 pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
530 * Generates the code to convert from a pointer (`Box<T>`, `&T`, etc)
531 * into an object (`Box<Trait>`, `&Trait`, etc). This means creating a
532 * pair where the first word is the vtable and the second word is
537 let _icx = push_ctxt("meth::trans_cast");
539 let lldest = match dest {
541 return datum.clean(bcx, "trait_cast", id);
548 let llbox_ty = type_of(bcx.ccx(), datum.ty);
550 // Store the pointer into the first half of pair.
551 let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
552 llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
553 bcx = datum.store_to(bcx, llboxdest);
555 // Store the vtable into the second half of pair.
557 let vtable_map = ccx.tcx.vtable_map.borrow();
558 resolve_param_vtables_under_param_substs(ccx.tcx(),
559 bcx.fcx.param_substs,
560 vtable_map.get(&MethodCall::expr(id)).get(0).as_slice())
562 let vtable = get_vtable(bcx, v_ty, origins);
563 let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
564 let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
565 Store(bcx, vtable, llvtabledest);