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(),
80 let mut v = TransItemVisitor{ ccx: ccx };
81 visit::walk_method_helper(&mut v, &**method, ());
86 pub fn trans_method_callee<'a>(
88 method_call: MethodCall,
89 self_expr: Option<&ast::Expr>,
90 arg_cleanup_scope: cleanup::ScopeId)
92 let _icx = push_ctxt("meth::trans_method_callee");
94 let (origin, method_ty) = match bcx.tcx().method_map
95 .borrow().find(&method_call) {
97 debug!("trans_method_callee({:?}, method={})",
98 method_call, method.repr(bcx.tcx()));
99 (method.origin, method.ty)
102 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
103 "method call expr wasn't in method map")
108 typeck::MethodStatic(did) |
109 typeck::MethodStaticUnboxedClosure(did) => {
112 data: Fn(callee::trans_fn_ref(bcx,
114 MethodCall(method_call))),
117 typeck::MethodParam(typeck::MethodParam {
123 ty::populate_implementations_for_trait_if_necessary(
127 let vtbl = find_vtable(bcx.tcx(), bcx.fcx.param_substs, p, b);
128 trans_monomorphized_callee(bcx, method_call,
132 typeck::MethodObject(ref mt) => {
133 let self_expr = match self_expr {
134 Some(self_expr) => self_expr,
136 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
137 "self expr wasn't provided for trait object \
138 callee (trying to call overloaded op?)")
141 trans_trait_callee(bcx,
142 monomorphize_type(bcx, method_ty),
150 pub fn trans_static_method_callee(bcx: &Block,
151 method_id: ast::DefId,
152 trait_id: ast::DefId,
153 expr_id: ast::NodeId)
155 let _icx = push_ctxt("meth::trans_static_method_callee");
158 debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
161 ty::item_path_str(bcx.tcx(), trait_id),
163 let _indenter = indenter();
165 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
167 let mname = if method_id.krate == ast::LOCAL_CRATE {
168 match bcx.tcx().map.get(method_id.node) {
169 ast_map::NodeTraitMethod(method) => {
170 let ident = match *method {
171 ast::Required(ref m) => m.ident,
172 ast::Provided(ref m) => m.pe_ident()
176 _ => fail!("callee is not a trait method")
179 csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
181 debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
182 name={}", method_id, expr_id, token::get_name(mname));
184 let vtable_key = MethodCall::expr(expr_id);
185 let vtbls = resolve_vtables_in_fn_ctxt(
187 ccx.tcx.vtable_map.borrow().get(&vtable_key));
189 match *vtbls.get_self().unwrap().get(0) {
190 typeck::vtable_static(impl_did, ref rcvr_substs, ref rcvr_origins) => {
191 assert!(rcvr_substs.types.all(|t| !ty::type_needs_infer(*t)));
193 let mth_id = method_with_name(ccx, impl_did, mname);
194 let (callee_substs, callee_origins) =
195 combine_impl_and_methods_tps(
196 bcx, ExprId(expr_id),
197 (*rcvr_substs).clone(), (*rcvr_origins).clone());
199 let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
203 let callee_ty = node_id_type(bcx, expr_id);
204 let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
205 PointerCast(bcx, llfn, llty)
207 typeck::vtable_unboxed_closure(_) => {
208 bcx.tcx().sess.bug("can't call a closure vtable in a static way");
211 fail!("vtable_param left in monomorphized \
212 function's vtable substs");
217 fn method_with_name(ccx: &CrateContext,
219 name: ast::Name) -> ast::DefId {
220 match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
225 let methods = ccx.tcx.impl_methods.borrow();
226 let methods = methods.find(&impl_id)
227 .expect("could not find impl while translating");
228 let meth_did = methods.iter().find(|&did| ty::method(&ccx.tcx, *did).ident.name == name)
229 .expect("could not find method while translating");
231 ccx.impl_method_cache.borrow_mut().insert((impl_id, name), *meth_did);
235 fn trans_monomorphized_callee<'a>(
237 method_call: MethodCall,
238 trait_id: ast::DefId,
240 vtbl: typeck::vtable_origin)
242 let _icx = push_ctxt("meth::trans_monomorphized_callee");
244 typeck::vtable_static(impl_did, rcvr_substs, rcvr_origins) => {
246 let mname = ty::trait_method(ccx.tcx(), trait_id, n_method).ident;
247 let mth_id = method_with_name(bcx.ccx(), impl_did, mname.name);
249 // create a concatenated set of substitutions which includes
250 // those from the impl and those from the method:
251 let (callee_substs, callee_origins) =
252 combine_impl_and_methods_tps(
253 bcx, MethodCall(method_call), rcvr_substs, rcvr_origins);
255 // translate the function
256 let llfn = trans_fn_ref_with_vtables(bcx,
258 MethodCall(method_call),
262 Callee { bcx: bcx, data: Fn(llfn) }
264 typeck::vtable_unboxed_closure(closure_def_id) => {
265 // The static region and type parameters are lies, but we're in
266 // trans so it doesn't matter.
268 // FIXME(pcwalton): Is this true in the case of type parameters?
269 let callee_substs = get_callee_substitutions_for_unboxed_closure(
273 let llfn = trans_fn_ref_with_vtables(bcx,
275 MethodCall(method_call),
277 VecPerParamSpace::empty());
284 typeck::vtable_param(..) => {
286 "vtable_param left in monomorphized function's vtable substs");
288 typeck::vtable_error => {
290 "vtable_error left in monomorphized function's vtable substs");
295 fn combine_impl_and_methods_tps(bcx: &Block,
296 node: ExprOrMethodCall,
297 rcvr_substs: subst::Substs,
298 rcvr_origins: typeck::vtable_res)
299 -> (subst::Substs, typeck::vtable_res)
302 * Creates a concatenated set of substitutions which includes
303 * those from the impl and those from the method. This are
304 * some subtle complications here. Statically, we have a list
305 * of type parameters like `[T0, T1, T2, M1, M2, M3]` where
306 * `Tn` are type parameters that appear on the receiver. For
307 * example, if the receiver is a method parameter `A` with a
308 * bound like `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
310 * The weird part is that the type `A` might now be bound to
311 * any other type, such as `foo<X>`. In that case, the vector
312 * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is
313 * to slice off the method type parameters and append them to
314 * the type parameters from the type that the receiver is
320 let vtable_key = match node {
321 ExprId(id) => MethodCall::expr(id),
322 MethodCall(method_call) => method_call
324 let node_substs = node_id_substs(bcx, node);
325 let node_vtables = node_vtables(bcx, vtable_key);
327 debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
328 debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
330 // Break apart the type parameters from the node and type
331 // parameters from the receiver.
332 let (_, _, node_method) = node_substs.types.split();
333 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_substs.types.clone().split();
334 assert!(rcvr_method.is_empty());
335 let ty_substs = subst::Substs {
336 regions: subst::ErasedRegions,
337 types: subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method)
340 // Now do the same work for the vtables.
341 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_origins.split();
342 let (_, _, node_method) = node_vtables.split();
343 assert!(rcvr_method.is_empty());
344 let vtables = subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method);
349 fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
352 self_expr: &ast::Expr,
353 arg_cleanup_scope: cleanup::ScopeId)
356 * Create a method callee where the method is coming from a trait
357 * object (e.g., Box<Trait> type). In this case, we must pull the fn
358 * pointer out of the vtable that is packaged up with the object.
359 * Objects are represented as a pair, so we first evaluate the self
360 * expression and then extract the self data and vtable out of the
364 let _icx = push_ctxt("meth::trans_trait_callee");
367 // Translate self_datum and take ownership of the value by
368 // converting to an rvalue.
369 let self_datum = unpack_datum!(
370 bcx, expr::trans(bcx, self_expr));
372 let llval = if ty::type_needs_drop(bcx.tcx(), self_datum.ty) {
373 let self_datum = unpack_datum!(
374 bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
376 // Convert to by-ref since `trans_trait_callee_from_llval` wants it
378 let self_datum = unpack_datum!(
379 bcx, self_datum.to_ref_datum(bcx));
381 // Arrange cleanup in case something should go wrong before the
382 // actual call occurs.
383 self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
385 // We don't have to do anything about cleanups for &Trait and &mut Trait.
386 assert!(self_datum.kind.is_by_ref());
390 trans_trait_callee_from_llval(bcx, method_ty, n_method, llval)
393 pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
399 * Same as `trans_trait_callee()` above, except that it is given
400 * a by-ref pointer to the object pair.
403 let _icx = push_ctxt("meth::trans_trait_callee");
406 // Load the data pointer from the object.
407 debug!("(translating trait callee) loading second index from pair");
408 let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
409 let llbox = Load(bcx, llboxptr);
410 let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
412 // Load the function from the vtable and cast it to the expected type.
413 debug!("(translating trait callee) loading method");
414 // Replace the self type (&Self or Box<Self>) with an opaque pointer.
415 let llcallee_ty = match ty::get(callee_ty).sty {
416 ty::ty_bare_fn(ref f) if f.abi == Rust || f.abi == RustCall => {
418 Some(Type::i8p(ccx)),
419 f.sig.inputs.slice_from(1),
424 ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
427 let llvtable = Load(bcx,
430 [0u, abi::trt_field_vtable]),
431 Type::vtable(ccx).ptr_to().ptr_to()));
432 let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1]));
433 let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
437 data: TraitMethod(MethodData {
444 /// Creates the self type and (fake) callee substitutions for an unboxed
445 /// closure with the given def ID. The static region and type parameters are
446 /// lies, but we're in trans so it doesn't matter.
447 fn get_callee_substitutions_for_unboxed_closure(bcx: &Block,
450 let self_ty = ty::mk_unboxed_closure(bcx.tcx(), def_id);
451 subst::Substs::erased(
452 VecPerParamSpace::new(Vec::new(),
454 ty::mk_rptr(bcx.tcx(),
458 mutbl: ast::MutMutable,
464 /// Creates a returns a dynamic vtable for the given type and vtable origin.
465 /// This is used only for objects.
466 fn get_vtable(bcx: &Block,
468 origins: typeck::vtable_param_res)
471 debug!("get_vtable(self_ty={}, origins={})",
472 self_ty.repr(bcx.tcx()),
473 origins.repr(bcx.tcx()));
476 let _icx = push_ctxt("meth::get_vtable");
479 let hash_id = (self_ty, monomorphize::make_vtable_id(ccx, origins.get(0)));
480 match ccx.vtables.borrow().find(&hash_id) {
481 Some(&val) => { return val }
485 // Not in the cache. Actually build it.
486 let methods = origins.move_iter().flat_map(|origin| {
488 typeck::vtable_static(id, substs, sub_vtables) => {
489 emit_vtable_methods(bcx, id, substs, sub_vtables).move_iter()
491 typeck::vtable_unboxed_closure(closure_def_id) => {
493 get_callee_substitutions_for_unboxed_closure(
497 let llfn = trans_fn_ref_with_vtables(
502 VecPerParamSpace::empty());
504 (vec!(llfn)).move_iter()
506 _ => ccx.sess().bug("get_vtable: expected a static origin"),
510 // Generate a destructor for the vtable.
511 let drop_glue = glue::get_drop_glue(ccx, self_ty);
512 let vtable = make_vtable(ccx, drop_glue, methods);
514 ccx.vtables.borrow_mut().insert(hash_id, vtable);
518 /// Helper function to declare and initialize the vtable.
519 pub fn make_vtable<I: Iterator<ValueRef>>(ccx: &CrateContext,
523 let _icx = push_ctxt("meth::make_vtable");
525 let components: Vec<_> = Some(drop_glue).move_iter().chain(ptrs).collect();
528 let tbl = C_struct(ccx, components.as_slice(), false);
529 let sym = token::gensym("vtable");
530 let vt_gvar = format!("vtable{}", sym).with_c_str(|buf| {
531 llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
533 llvm::LLVMSetInitializer(vt_gvar, tbl);
534 llvm::LLVMSetGlobalConstant(vt_gvar, llvm::True);
535 llvm::SetLinkage(vt_gvar, llvm::InternalLinkage);
540 fn emit_vtable_methods(bcx: &Block,
542 substs: subst::Substs,
543 vtables: typeck::vtable_res)
548 let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
549 Some(t_id) => t_id.def_id,
550 None => ccx.sess().bug("make_impl_vtable: don't know how to \
551 make a vtable for a type impl!")
554 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trt_id);
556 let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
557 trait_method_def_ids.iter().map(|method_def_id| {
558 let ident = ty::method(tcx, *method_def_id).ident;
559 // The substitutions we have are on the impl, so we grab
560 // the method type from the impl to substitute into.
561 let m_id = method_with_name(ccx, impl_id, ident.name);
562 let m = ty::method(tcx, m_id);
563 debug!("(making impl vtable) emitting method {} at subst {}",
566 if m.generics.has_type_params(subst::FnSpace) ||
567 ty::type_has_self(ty::mk_bare_fn(tcx, m.fty.clone())) {
568 debug!("(making impl vtable) method has self or type params: {}",
569 token::get_ident(ident));
570 C_null(Type::nil(ccx).ptr_to())
572 let mut fn_ref = trans_fn_ref_with_vtables(bcx,
577 if m.explicit_self == ty::ByValueExplicitSelfCategory {
578 fn_ref = trans_unboxing_shim(bcx,
589 pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
595 * Generates the code to convert from a pointer (`Box<T>`, `&T`, etc)
596 * into an object (`Box<Trait>`, `&Trait`, etc). This means creating a
597 * pair where the first word is the vtable and the second word is
602 let _icx = push_ctxt("meth::trans_cast");
604 let lldest = match dest {
606 return datum.clean(bcx, "trait_cast", id);
613 let llbox_ty = type_of(bcx.ccx(), datum.ty);
615 // Store the pointer into the first half of pair.
616 let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
617 llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
618 bcx = datum.store_to(bcx, llboxdest);
620 // Store the vtable into the second half of pair.
622 let vtable_map = ccx.tcx.vtable_map.borrow();
623 // This trait cast might be because of implicit coercion
624 let method_call = match ccx.tcx.adjustments.borrow().find(&id) {
625 Some(&ty::AutoObject(..)) => MethodCall::autoobject(id),
626 _ => MethodCall::expr(id)
628 let vres = vtable_map.get(&method_call).get_self().unwrap();
629 resolve_param_vtables_under_param_substs(ccx.tcx(), bcx.fcx.param_substs, vres)
631 let vtable = get_vtable(bcx, v_ty, origins);
632 let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
633 let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
634 Store(bcx, vtable, llvtabledest);