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;
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;
40 use syntax::parse::token;
41 use syntax::{ast, ast_map, visit, ast_util};
44 The main "translation" pass for methods. Generates code
45 for non-monomorphized methods only. Other methods will
46 be generated once they are invoked with specific type parameters,
47 see `trans::base::lval_static_fn()` or `trans::base::monomorphic_fn()`.
49 pub fn trans_impl(ccx: &CrateContext,
51 methods: &[Gc<ast::Method>],
52 generics: &ast::Generics,
54 let _icx = push_ctxt("meth::trans_impl");
57 debug!("trans_impl(name={}, id={:?})", name.repr(tcx), id);
59 // Both here and below with generic methods, be sure to recurse and look for
60 // items that we need to translate.
61 if !generics.ty_params.is_empty() {
62 let mut v = TransItemVisitor{ ccx: ccx };
63 for method in methods.iter() {
64 visit::walk_method_helper(&mut v, &**method, ());
68 for method in methods.iter() {
69 if ast_util::method_generics(&**method).ty_params.len() == 0u {
70 let llfn = get_item_val(ccx, method.id);
71 trans_fn(ccx, ast_util::method_fn_decl(&**method),
72 ast_util::method_body(&**method),
73 llfn, ¶m_substs::empty(), method.id, []);
75 let mut v = TransItemVisitor{ ccx: ccx };
76 visit::walk_method_helper(&mut v, &**method, ());
81 pub fn trans_method_callee<'a>(
83 method_call: MethodCall,
84 self_expr: Option<&ast::Expr>,
85 arg_cleanup_scope: cleanup::ScopeId)
87 let _icx = push_ctxt("meth::trans_method_callee");
89 let (origin, method_ty) = match bcx.tcx().method_map
90 .borrow().find(&method_call) {
92 debug!("trans_method_callee({:?}, method={})",
93 method_call, method.repr(bcx.tcx()));
94 (method.origin, method.ty)
97 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
98 "method call expr wasn't in method map")
103 typeck::MethodStatic(did) => {
106 data: Fn(callee::trans_fn_ref(bcx, did, MethodCall(method_call)))
109 typeck::MethodParam(typeck::MethodParam {
115 ty::populate_implementations_for_trait_if_necessary(
119 let vtbl = find_vtable(bcx.tcx(), bcx.fcx.param_substs, p, b);
120 trans_monomorphized_callee(bcx, method_call,
124 typeck::MethodObject(ref mt) => {
125 let self_expr = match self_expr {
126 Some(self_expr) => self_expr,
128 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
129 "self expr wasn't provided for trait object \
130 callee (trying to call overloaded op?)")
133 trans_trait_callee(bcx,
134 monomorphize_type(bcx, method_ty),
142 pub fn trans_static_method_callee(bcx: &Block,
143 method_id: ast::DefId,
144 trait_id: ast::DefId,
145 expr_id: ast::NodeId)
147 let _icx = push_ctxt("meth::trans_static_method_callee");
150 debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
153 ty::item_path_str(bcx.tcx(), trait_id),
155 let _indenter = indenter();
157 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
159 let mname = if method_id.krate == ast::LOCAL_CRATE {
160 match bcx.tcx().map.get(method_id.node) {
161 ast_map::NodeTraitMethod(method) => {
162 let ident = match *method {
163 ast::Required(ref m) => m.ident,
164 ast::Provided(ref m) => ast_util::method_ident(&**m)
168 _ => fail!("callee is not a trait method")
171 csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
173 debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
174 name={}", method_id, expr_id, token::get_name(mname));
176 let vtable_key = MethodCall::expr(expr_id);
177 let vtbls = resolve_vtables_in_fn_ctxt(
179 ccx.tcx.vtable_map.borrow().get(&vtable_key));
181 match *vtbls.get_self().unwrap().get(0) {
182 typeck::vtable_static(impl_did, ref rcvr_substs, ref rcvr_origins) => {
183 assert!(rcvr_substs.types.all(|t| !ty::type_needs_infer(*t)));
185 let mth_id = method_with_name(ccx, impl_did, mname);
186 let (callee_substs, callee_origins) =
187 combine_impl_and_methods_tps(
188 bcx, ExprId(expr_id),
189 (*rcvr_substs).clone(), (*rcvr_origins).clone());
191 let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
195 let callee_ty = node_id_type(bcx, expr_id);
196 let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
197 PointerCast(bcx, llfn, llty)
200 fail!("vtable_param left in monomorphized \
201 function's vtable substs");
206 fn method_with_name(ccx: &CrateContext,
208 name: ast::Name) -> ast::DefId {
209 match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
214 let methods = ccx.tcx.impl_methods.borrow();
215 let methods = methods.find(&impl_id)
216 .expect("could not find impl while translating");
217 let meth_did = methods.iter().find(|&did| ty::method(&ccx.tcx, *did).ident.name == name)
218 .expect("could not find method while translating");
220 ccx.impl_method_cache.borrow_mut().insert((impl_id, name), *meth_did);
224 fn trans_monomorphized_callee<'a>(bcx: &'a Block<'a>,
225 method_call: MethodCall,
226 trait_id: ast::DefId,
228 vtbl: typeck::vtable_origin)
230 let _icx = push_ctxt("meth::trans_monomorphized_callee");
232 typeck::vtable_static(impl_did, rcvr_substs, rcvr_origins) => {
234 let mname = ty::trait_method(ccx.tcx(), trait_id, n_method).ident;
235 let mth_id = method_with_name(bcx.ccx(), impl_did, mname.name);
237 // create a concatenated set of substitutions which includes
238 // those from the impl and those from the method:
239 let (callee_substs, callee_origins) =
240 combine_impl_and_methods_tps(
241 bcx, MethodCall(method_call), rcvr_substs, rcvr_origins);
243 // translate the function
244 let llfn = trans_fn_ref_with_vtables(bcx,
246 MethodCall(method_call),
250 Callee { bcx: bcx, data: Fn(llfn) }
252 typeck::vtable_param(..) => {
254 "vtable_param left in monomorphized function's vtable substs");
256 typeck::vtable_error => {
258 "vtable_error left in monomorphized function's vtable substs");
263 fn combine_impl_and_methods_tps(bcx: &Block,
264 node: ExprOrMethodCall,
265 rcvr_substs: subst::Substs,
266 rcvr_origins: typeck::vtable_res)
267 -> (subst::Substs, typeck::vtable_res)
270 * Creates a concatenated set of substitutions which includes
271 * those from the impl and those from the method. This are
272 * some subtle complications here. Statically, we have a list
273 * of type parameters like `[T0, T1, T2, M1, M2, M3]` where
274 * `Tn` are type parameters that appear on the receiver. For
275 * example, if the receiver is a method parameter `A` with a
276 * bound like `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
278 * The weird part is that the type `A` might now be bound to
279 * any other type, such as `foo<X>`. In that case, the vector
280 * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is
281 * to slice off the method type parameters and append them to
282 * the type parameters from the type that the receiver is
288 let vtable_key = match node {
289 ExprId(id) => MethodCall::expr(id),
290 MethodCall(method_call) => method_call
292 let node_substs = node_id_substs(bcx, node);
293 let node_vtables = node_vtables(bcx, vtable_key);
295 debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
296 debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
298 // Break apart the type parameters from the node and type
299 // parameters from the receiver.
300 let (_, _, node_method) = node_substs.types.split();
301 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_substs.types.clone().split();
302 assert!(rcvr_method.is_empty());
303 let ty_substs = subst::Substs {
304 regions: subst::ErasedRegions,
305 types: subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method)
308 // Now do the same work for the vtables.
309 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_origins.split();
310 let (_, _, node_method) = node_vtables.split();
311 assert!(rcvr_method.is_empty());
312 let vtables = subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method);
317 fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
320 self_expr: &ast::Expr,
321 arg_cleanup_scope: cleanup::ScopeId)
324 * Create a method callee where the method is coming from a trait
325 * object (e.g., Box<Trait> type). In this case, we must pull the fn
326 * pointer out of the vtable that is packaged up with the object.
327 * Objects are represented as a pair, so we first evaluate the self
328 * expression and then extract the self data and vtable out of the
332 let _icx = push_ctxt("meth::trans_trait_callee");
335 // Translate self_datum and take ownership of the value by
336 // converting to an rvalue.
337 let self_datum = unpack_datum!(
338 bcx, expr::trans(bcx, self_expr));
340 let llval = if ty::type_needs_drop(bcx.tcx(), self_datum.ty) {
341 let self_datum = unpack_datum!(
342 bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
344 // Convert to by-ref since `trans_trait_callee_from_llval` wants it
346 let self_datum = unpack_datum!(
347 bcx, self_datum.to_ref_datum(bcx));
349 // Arrange cleanup in case something should go wrong before the
350 // actual call occurs.
351 self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
353 // We don't have to do anything about cleanups for &Trait and &mut Trait.
354 assert!(self_datum.kind.is_by_ref());
358 trans_trait_callee_from_llval(bcx, method_ty, n_method, llval)
361 pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
367 * Same as `trans_trait_callee()` above, except that it is given
368 * a by-ref pointer to the object pair.
371 let _icx = push_ctxt("meth::trans_trait_callee");
374 // Load the data pointer from the object.
375 debug!("(translating trait callee) loading second index from pair");
376 let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
377 let llbox = Load(bcx, llboxptr);
378 let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
380 // Load the function from the vtable and cast it to the expected type.
381 debug!("(translating trait callee) loading method");
382 // Replace the self type (&Self or Box<Self>) with an opaque pointer.
383 let llcallee_ty = match ty::get(callee_ty).sty {
384 ty::ty_bare_fn(ref f) if f.abi == Rust => {
385 type_of_rust_fn(ccx, true, f.sig.inputs.slice_from(1), f.sig.output)
388 ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
391 let llvtable = Load(bcx,
394 [0u, abi::trt_field_vtable]),
395 Type::vtable(ccx).ptr_to().ptr_to()));
396 let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1]));
397 let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
401 data: TraitMethod(MethodData {
408 /// Creates a returns a dynamic vtable for the given type and vtable origin.
409 /// This is used only for objects.
410 fn get_vtable(bcx: &Block,
412 origins: typeck::vtable_param_res)
415 debug!("get_vtable(self_ty={}, origins={})",
416 self_ty.repr(bcx.tcx()),
417 origins.repr(bcx.tcx()));
420 let _icx = push_ctxt("meth::get_vtable");
423 let hash_id = (self_ty, monomorphize::make_vtable_id(ccx, origins.get(0)));
424 match ccx.vtables.borrow().find(&hash_id) {
425 Some(&val) => { return val }
429 // Not in the cache. Actually build it.
430 let methods = origins.move_iter().flat_map(|origin| {
432 typeck::vtable_static(id, substs, sub_vtables) => {
433 emit_vtable_methods(bcx, id, substs, sub_vtables).move_iter()
435 _ => ccx.sess().bug("get_vtable: expected a static origin"),
439 // Generate a destructor for the vtable.
440 let drop_glue = glue::get_drop_glue(ccx, self_ty);
441 let vtable = make_vtable(ccx, drop_glue, methods);
443 ccx.vtables.borrow_mut().insert(hash_id, vtable);
447 /// Helper function to declare and initialize the vtable.
448 pub fn make_vtable<I: Iterator<ValueRef>>(ccx: &CrateContext,
452 let _icx = push_ctxt("meth::make_vtable");
454 let components: Vec<_> = Some(drop_glue).move_iter().chain(ptrs).collect();
457 let tbl = C_struct(ccx, components.as_slice(), false);
458 let sym = token::gensym("vtable");
459 let vt_gvar = format!("vtable{}", sym).with_c_str(|buf| {
460 llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
462 llvm::LLVMSetInitializer(vt_gvar, tbl);
463 llvm::LLVMSetGlobalConstant(vt_gvar, lib::llvm::True);
464 lib::llvm::SetLinkage(vt_gvar, lib::llvm::InternalLinkage);
469 fn emit_vtable_methods(bcx: &Block,
471 substs: subst::Substs,
472 vtables: typeck::vtable_res)
477 let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
478 Some(t_id) => t_id.def_id,
479 None => ccx.sess().bug("make_impl_vtable: don't know how to \
480 make a vtable for a type impl!")
483 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trt_id);
485 let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
486 trait_method_def_ids.iter().map(|method_def_id| {
487 let ident = ty::method(tcx, *method_def_id).ident;
488 // The substitutions we have are on the impl, so we grab
489 // the method type from the impl to substitute into.
490 let m_id = method_with_name(ccx, impl_id, ident.name);
491 let m = ty::method(tcx, m_id);
492 debug!("(making impl vtable) emitting method {} at subst {}",
495 if m.generics.has_type_params(subst::FnSpace) ||
496 ty::type_has_self(ty::mk_bare_fn(tcx, m.fty.clone())) {
497 debug!("(making impl vtable) method has self or type params: {}",
498 token::get_ident(ident));
499 C_null(Type::nil(ccx).ptr_to())
501 let mut fn_ref = trans_fn_ref_with_vtables(bcx,
506 match m.explicit_self {
507 ast::SelfValue(_) => {
508 fn_ref = trans_unboxing_shim(bcx,
521 pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
527 * Generates the code to convert from a pointer (`Box<T>`, `&T`, etc)
528 * into an object (`Box<Trait>`, `&Trait`, etc). This means creating a
529 * pair where the first word is the vtable and the second word is
534 let _icx = push_ctxt("meth::trans_cast");
536 let lldest = match dest {
538 return datum.clean(bcx, "trait_cast", id);
545 let llbox_ty = type_of(bcx.ccx(), datum.ty);
547 // Store the pointer into the first half of pair.
548 let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
549 llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
550 bcx = datum.store_to(bcx, llboxdest);
552 // Store the vtable into the second half of pair.
554 let vtable_map = ccx.tcx.vtable_map.borrow();
555 // This trait cast might be because of implicit coercion
556 let method_call = match ccx.tcx.adjustments.borrow().find(&id) {
557 Some(&ty::AutoObject(..)) => MethodCall::autoobject(id),
558 _ => MethodCall::expr(id)
560 let vres = vtable_map.get(&method_call).get_self().unwrap();
561 resolve_param_vtables_under_param_substs(ccx.tcx(), bcx.fcx.param_substs, vres)
563 let vtable = get_vtable(bcx, v_ty, origins);
564 let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
565 let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
566 Store(bcx, vtable, llvtabledest);