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.
15 use metadata::csearch;
16 use middle::subst::VecPerParamSpace;
18 use middle::trans::base::*;
19 use middle::trans::build::*;
20 use middle::trans::callee::*;
21 use middle::trans::callee;
22 use middle::trans::cleanup;
23 use middle::trans::common::*;
24 use middle::trans::datum::*;
25 use middle::trans::expr::{SaveIn, Ignore};
26 use middle::trans::expr;
27 use middle::trans::glue;
28 use middle::trans::monomorphize;
29 use middle::trans::type_::Type;
30 use middle::trans::type_of::*;
33 use middle::typeck::MethodCall;
34 use util::common::indenter;
35 use util::ppaux::Repr;
37 use std::c_str::ToCStr;
39 use syntax::abi::{Rust, RustCall};
40 use syntax::parse::token;
41 use syntax::{ast, ast_map, visit};
42 use syntax::ast_util::PostExpansionMethod;
45 The main "translation" pass for methods. Generates code
46 for non-monomorphized methods only. Other methods will
47 be generated once they are invoked with specific type parameters,
48 see `trans::base::lval_static_fn()` or `trans::base::monomorphic_fn()`.
50 pub fn trans_impl(ccx: &CrateContext,
52 methods: &[Gc<ast::Method>],
53 generics: &ast::Generics,
55 let _icx = push_ctxt("meth::trans_impl");
58 debug!("trans_impl(name={}, id={:?})", name.repr(tcx), id);
60 // Both here and below with generic methods, be sure to recurse and look for
61 // items that we need to translate.
62 if !generics.ty_params.is_empty() {
63 let mut v = TransItemVisitor{ ccx: ccx };
64 for method in methods.iter() {
65 visit::walk_method_helper(&mut v, &**method, ());
69 for method in methods.iter() {
70 if method.pe_generics().ty_params.len() == 0u {
71 let llfn = get_item_val(ccx, method.id);
73 &*method.pe_fn_decl(),
76 ¶m_substs::empty(),
81 let mut v = TransItemVisitor{ ccx: ccx };
82 visit::walk_method_helper(&mut v, &**method, ());
87 pub fn trans_method_callee<'a>(
89 method_call: MethodCall,
90 self_expr: Option<&ast::Expr>,
91 arg_cleanup_scope: cleanup::ScopeId)
93 let _icx = push_ctxt("meth::trans_method_callee");
95 let (origin, method_ty) = match bcx.tcx().method_map
96 .borrow().find(&method_call) {
98 debug!("trans_method_callee({:?}, method={})",
99 method_call, method.repr(bcx.tcx()));
100 (method.origin, method.ty)
103 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
104 "method call expr wasn't in method map")
109 typeck::MethodStatic(did) |
110 typeck::MethodStaticUnboxedClosure(did) => {
113 data: Fn(callee::trans_fn_ref(bcx,
115 MethodCall(method_call))),
118 typeck::MethodParam(typeck::MethodParam {
124 ty::populate_implementations_for_trait_if_necessary(
128 let vtbl = find_vtable(bcx.tcx(), bcx.fcx.param_substs, p, b);
129 trans_monomorphized_callee(bcx, method_call,
133 typeck::MethodObject(ref mt) => {
134 let self_expr = match self_expr {
135 Some(self_expr) => self_expr,
137 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
138 "self expr wasn't provided for trait object \
139 callee (trying to call overloaded op?)")
142 trans_trait_callee(bcx,
143 monomorphize_type(bcx, method_ty),
151 pub fn trans_static_method_callee(bcx: &Block,
152 method_id: ast::DefId,
153 trait_id: ast::DefId,
154 expr_id: ast::NodeId)
156 let _icx = push_ctxt("meth::trans_static_method_callee");
159 debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
162 ty::item_path_str(bcx.tcx(), trait_id),
164 let _indenter = indenter();
166 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
168 let mname = if method_id.krate == ast::LOCAL_CRATE {
169 match bcx.tcx().map.get(method_id.node) {
170 ast_map::NodeTraitMethod(method) => {
171 let ident = match *method {
172 ast::Required(ref m) => m.ident,
173 ast::Provided(ref m) => m.pe_ident()
177 _ => fail!("callee is not a trait method")
180 csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
182 debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
183 name={}", method_id, expr_id, token::get_name(mname));
185 let vtable_key = MethodCall::expr(expr_id);
186 let vtbls = resolve_vtables_in_fn_ctxt(
188 ccx.tcx.vtable_map.borrow().get(&vtable_key));
190 match *vtbls.get_self().unwrap().get(0) {
191 typeck::vtable_static(impl_did, ref rcvr_substs, ref rcvr_origins) => {
192 assert!(rcvr_substs.types.all(|t| !ty::type_needs_infer(*t)));
194 let mth_id = method_with_name(ccx, impl_did, mname);
195 let (callee_substs, callee_origins) =
196 combine_impl_and_methods_tps(
197 bcx, ExprId(expr_id),
198 (*rcvr_substs).clone(), (*rcvr_origins).clone());
200 let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
204 let callee_ty = node_id_type(bcx, expr_id);
205 let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
206 PointerCast(bcx, llfn, llty)
208 typeck::vtable_unboxed_closure(_) => {
209 bcx.tcx().sess.bug("can't call a closure vtable in a static way");
212 fail!("vtable_param left in monomorphized \
213 function's vtable substs");
218 fn method_with_name(ccx: &CrateContext,
220 name: ast::Name) -> ast::DefId {
221 match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
226 let methods = ccx.tcx.impl_methods.borrow();
227 let methods = methods.find(&impl_id)
228 .expect("could not find impl while translating");
229 let meth_did = methods.iter().find(|&did| ty::method(&ccx.tcx, *did).ident.name == name)
230 .expect("could not find method while translating");
232 ccx.impl_method_cache.borrow_mut().insert((impl_id, name), *meth_did);
236 fn trans_monomorphized_callee<'a>(
238 method_call: MethodCall,
239 trait_id: ast::DefId,
241 vtbl: typeck::vtable_origin)
243 let _icx = push_ctxt("meth::trans_monomorphized_callee");
245 typeck::vtable_static(impl_did, rcvr_substs, rcvr_origins) => {
247 let mname = ty::trait_method(ccx.tcx(), trait_id, n_method).ident;
248 let mth_id = method_with_name(bcx.ccx(), impl_did, mname.name);
250 // create a concatenated set of substitutions which includes
251 // those from the impl and those from the method:
252 let (callee_substs, callee_origins) =
253 combine_impl_and_methods_tps(
254 bcx, MethodCall(method_call), rcvr_substs, rcvr_origins);
256 // translate the function
257 let llfn = trans_fn_ref_with_vtables(bcx,
259 MethodCall(method_call),
263 Callee { bcx: bcx, data: Fn(llfn) }
265 typeck::vtable_unboxed_closure(closure_def_id) => {
266 // The static region and type parameters are lies, but we're in
267 // trans so it doesn't matter.
269 // FIXME(pcwalton): Is this true in the case of type parameters?
270 let callee_substs = get_callee_substitutions_for_unboxed_closure(
274 let llfn = trans_fn_ref_with_vtables(bcx,
276 MethodCall(method_call),
278 VecPerParamSpace::empty());
285 typeck::vtable_param(..) => {
287 "vtable_param left in monomorphized function's vtable substs");
289 typeck::vtable_error => {
291 "vtable_error left in monomorphized function's vtable substs");
296 fn combine_impl_and_methods_tps(bcx: &Block,
297 node: ExprOrMethodCall,
298 rcvr_substs: subst::Substs,
299 rcvr_origins: typeck::vtable_res)
300 -> (subst::Substs, typeck::vtable_res)
303 * Creates a concatenated set of substitutions which includes
304 * those from the impl and those from the method. This are
305 * some subtle complications here. Statically, we have a list
306 * of type parameters like `[T0, T1, T2, M1, M2, M3]` where
307 * `Tn` are type parameters that appear on the receiver. For
308 * example, if the receiver is a method parameter `A` with a
309 * bound like `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
311 * The weird part is that the type `A` might now be bound to
312 * any other type, such as `foo<X>`. In that case, the vector
313 * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is
314 * to slice off the method type parameters and append them to
315 * the type parameters from the type that the receiver is
321 let vtable_key = match node {
322 ExprId(id) => MethodCall::expr(id),
323 MethodCall(method_call) => method_call
325 let node_substs = node_id_substs(bcx, node);
326 let node_vtables = node_vtables(bcx, vtable_key);
328 debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
329 debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
331 // Break apart the type parameters from the node and type
332 // parameters from the receiver.
333 let (_, _, node_method) = node_substs.types.split();
334 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_substs.types.clone().split();
335 assert!(rcvr_method.is_empty());
336 let ty_substs = subst::Substs {
337 regions: subst::ErasedRegions,
338 types: subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method)
341 // Now do the same work for the vtables.
342 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_origins.split();
343 let (_, _, node_method) = node_vtables.split();
344 assert!(rcvr_method.is_empty());
345 let vtables = subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method);
350 fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
353 self_expr: &ast::Expr,
354 arg_cleanup_scope: cleanup::ScopeId)
357 * Create a method callee where the method is coming from a trait
358 * object (e.g., Box<Trait> type). In this case, we must pull the fn
359 * pointer out of the vtable that is packaged up with the object.
360 * Objects are represented as a pair, so we first evaluate the self
361 * expression and then extract the self data and vtable out of the
365 let _icx = push_ctxt("meth::trans_trait_callee");
368 // Translate self_datum and take ownership of the value by
369 // converting to an rvalue.
370 let self_datum = unpack_datum!(
371 bcx, expr::trans(bcx, self_expr));
373 let llval = if ty::type_needs_drop(bcx.tcx(), self_datum.ty) {
374 let self_datum = unpack_datum!(
375 bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
377 // Convert to by-ref since `trans_trait_callee_from_llval` wants it
379 let self_datum = unpack_datum!(
380 bcx, self_datum.to_ref_datum(bcx));
382 // Arrange cleanup in case something should go wrong before the
383 // actual call occurs.
384 self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
386 // We don't have to do anything about cleanups for &Trait and &mut Trait.
387 assert!(self_datum.kind.is_by_ref());
391 trans_trait_callee_from_llval(bcx, method_ty, n_method, llval)
394 pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
400 * Same as `trans_trait_callee()` above, except that it is given
401 * a by-ref pointer to the object pair.
404 let _icx = push_ctxt("meth::trans_trait_callee");
407 // Load the data pointer from the object.
408 debug!("(translating trait callee) loading second index from pair");
409 let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
410 let llbox = Load(bcx, llboxptr);
411 let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
413 // Load the function from the vtable and cast it to the expected type.
414 debug!("(translating trait callee) loading method");
415 // Replace the self type (&Self or Box<Self>) with an opaque pointer.
416 let llcallee_ty = match ty::get(callee_ty).sty {
417 ty::ty_bare_fn(ref f) if f.abi == Rust || f.abi == RustCall => {
419 Some(Type::i8p(ccx)),
420 f.sig.inputs.slice_from(1),
425 ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
428 let llvtable = Load(bcx,
431 [0u, abi::trt_field_vtable]),
432 Type::vtable(ccx).ptr_to().ptr_to()));
433 let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1]));
434 let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
438 data: TraitMethod(MethodData {
445 /// Creates the self type and (fake) callee substitutions for an unboxed
446 /// closure with the given def ID. The static region and type parameters are
447 /// lies, but we're in trans so it doesn't matter.
448 fn get_callee_substitutions_for_unboxed_closure(bcx: &Block,
451 let self_ty = ty::mk_unboxed_closure(bcx.tcx(), def_id);
452 subst::Substs::erased(
453 VecPerParamSpace::new(Vec::new(),
455 ty::mk_rptr(bcx.tcx(),
459 mutbl: ast::MutMutable,
465 /// Creates a returns a dynamic vtable for the given type and vtable origin.
466 /// This is used only for objects.
467 fn get_vtable(bcx: &Block,
469 origins: typeck::vtable_param_res)
472 debug!("get_vtable(self_ty={}, origins={})",
473 self_ty.repr(bcx.tcx()),
474 origins.repr(bcx.tcx()));
477 let _icx = push_ctxt("meth::get_vtable");
480 let hash_id = (self_ty, monomorphize::make_vtable_id(ccx, origins.get(0)));
481 match ccx.vtables.borrow().find(&hash_id) {
482 Some(&val) => { return val }
486 // Not in the cache. Actually build it.
487 let methods = origins.move_iter().flat_map(|origin| {
489 typeck::vtable_static(id, substs, sub_vtables) => {
490 emit_vtable_methods(bcx, id, substs, sub_vtables).move_iter()
492 typeck::vtable_unboxed_closure(closure_def_id) => {
494 get_callee_substitutions_for_unboxed_closure(
498 let llfn = trans_fn_ref_with_vtables(
503 VecPerParamSpace::empty());
505 (vec!(llfn)).move_iter()
507 _ => ccx.sess().bug("get_vtable: expected a static origin"),
511 // Generate a destructor for the vtable.
512 let drop_glue = glue::get_drop_glue(ccx, self_ty);
513 let vtable = make_vtable(ccx, drop_glue, methods);
515 ccx.vtables.borrow_mut().insert(hash_id, vtable);
519 /// Helper function to declare and initialize the vtable.
520 pub fn make_vtable<I: Iterator<ValueRef>>(ccx: &CrateContext,
524 let _icx = push_ctxt("meth::make_vtable");
526 let components: Vec<_> = Some(drop_glue).move_iter().chain(ptrs).collect();
529 let tbl = C_struct(ccx, components.as_slice(), false);
530 let sym = token::gensym("vtable");
531 let vt_gvar = format!("vtable{}", sym.uint()).with_c_str(|buf| {
532 llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
534 llvm::LLVMSetInitializer(vt_gvar, tbl);
535 llvm::LLVMSetGlobalConstant(vt_gvar, llvm::True);
536 llvm::SetLinkage(vt_gvar, llvm::InternalLinkage);
541 fn emit_vtable_methods(bcx: &Block,
543 substs: subst::Substs,
544 vtables: typeck::vtable_res)
549 let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
550 Some(t_id) => t_id.def_id,
551 None => ccx.sess().bug("make_impl_vtable: don't know how to \
552 make a vtable for a type impl!")
555 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trt_id);
557 let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
558 trait_method_def_ids.iter().map(|method_def_id| {
559 let ident = ty::method(tcx, *method_def_id).ident;
560 // The substitutions we have are on the impl, so we grab
561 // the method type from the impl to substitute into.
562 let m_id = method_with_name(ccx, impl_id, ident.name);
563 let m = ty::method(tcx, m_id);
564 debug!("(making impl vtable) emitting method {} at subst {}",
567 if m.generics.has_type_params(subst::FnSpace) ||
568 ty::type_has_self(ty::mk_bare_fn(tcx, m.fty.clone())) {
569 debug!("(making impl vtable) method has self or type params: {}",
570 token::get_ident(ident));
571 C_null(Type::nil(ccx).ptr_to())
573 let mut fn_ref = trans_fn_ref_with_vtables(bcx,
578 if m.explicit_self == ty::ByValueExplicitSelfCategory {
579 fn_ref = trans_unboxing_shim(bcx,
590 pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
596 * Generates the code to convert from a pointer (`Box<T>`, `&T`, etc)
597 * into an object (`Box<Trait>`, `&Trait`, etc). This means creating a
598 * pair where the first word is the vtable and the second word is
603 let _icx = push_ctxt("meth::trans_cast");
605 let lldest = match dest {
607 return datum.clean(bcx, "trait_cast", id);
614 let llbox_ty = type_of(bcx.ccx(), datum.ty);
616 // Store the pointer into the first half of pair.
617 let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
618 llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
619 bcx = datum.store_to(bcx, llboxdest);
621 // Store the vtable into the second half of pair.
623 let vtable_map = ccx.tcx.vtable_map.borrow();
624 // This trait cast might be because of implicit coercion
625 let method_call = match ccx.tcx.adjustments.borrow().find(&id) {
626 Some(&ty::AutoObject(..)) => MethodCall::autoobject(id),
627 _ => MethodCall::expr(id)
629 let vres = vtable_map.get(&method_call).get_self().unwrap();
630 resolve_param_vtables_under_param_substs(ccx.tcx(), bcx.fcx.param_substs, vres)
632 let vtable = get_vtable(bcx, v_ty, origins);
633 let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
634 let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
635 Store(bcx, vtable, llvtabledest);