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};
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 method.generics.ty_params.len() == 0u {
70 let llfn = get_item_val(ccx, method.id);
71 trans_fn(ccx, &*method.decl, &*method.body,
72 llfn, ¶m_substs::empty(), method.id, []);
74 let mut v = TransItemVisitor{ ccx: ccx };
75 visit::walk_method_helper(&mut v, &**method, ());
80 pub fn trans_method_callee<'a>(
82 method_call: MethodCall,
83 self_expr: Option<&ast::Expr>,
84 arg_cleanup_scope: cleanup::ScopeId)
86 let _icx = push_ctxt("meth::trans_method_callee");
88 let (origin, method_ty) = match bcx.tcx().method_map
89 .borrow().find(&method_call) {
91 debug!("trans_method_callee({:?}, method={})",
92 method_call, method.repr(bcx.tcx()));
93 (method.origin, method.ty)
96 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
97 "method call expr wasn't in method map")
102 typeck::MethodStatic(did) => {
105 data: Fn(callee::trans_fn_ref(bcx, did, MethodCall(method_call)))
108 typeck::MethodParam(typeck::MethodParam {
114 ty::populate_implementations_for_trait_if_necessary(
118 let vtbl = find_vtable(bcx.tcx(), bcx.fcx.param_substs, p, b);
119 trans_monomorphized_callee(bcx, method_call,
123 typeck::MethodObject(ref mt) => {
124 let self_expr = match self_expr {
125 Some(self_expr) => self_expr,
127 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
128 "self expr wasn't provided for trait object \
129 callee (trying to call overloaded op?)")
132 trans_trait_callee(bcx,
133 monomorphize_type(bcx, method_ty),
141 pub fn trans_static_method_callee(bcx: &Block,
142 method_id: ast::DefId,
143 trait_id: ast::DefId,
144 expr_id: ast::NodeId)
146 let _icx = push_ctxt("meth::trans_static_method_callee");
149 debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
152 ty::item_path_str(bcx.tcx(), trait_id),
154 let _indenter = indenter();
156 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
158 let mname = if method_id.krate == ast::LOCAL_CRATE {
159 match bcx.tcx().map.get(method_id.node) {
160 ast_map::NodeTraitMethod(method) => {
161 let ident = match *method {
162 ast::Required(ref m) => m.ident,
163 ast::Provided(ref m) => m.ident
167 _ => fail!("callee is not a trait method")
170 csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
172 debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
173 name={}", method_id, expr_id, token::get_name(mname));
175 let vtable_key = MethodCall::expr(expr_id);
176 let vtbls = resolve_vtables_in_fn_ctxt(
178 ccx.tcx.vtable_map.borrow().get(&vtable_key));
180 match *vtbls.get_self().unwrap().get(0) {
181 typeck::vtable_static(impl_did, ref rcvr_substs, ref rcvr_origins) => {
182 assert!(rcvr_substs.types.all(|t| !ty::type_needs_infer(*t)));
184 let mth_id = method_with_name(ccx, impl_did, mname);
185 let (callee_substs, callee_origins) =
186 combine_impl_and_methods_tps(
187 bcx, ExprId(expr_id),
188 (*rcvr_substs).clone(), (*rcvr_origins).clone());
190 let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
194 let callee_ty = node_id_type(bcx, expr_id);
195 let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
196 PointerCast(bcx, llfn, llty)
199 fail!("vtable_param left in monomorphized \
200 function's vtable substs");
205 fn method_with_name(ccx: &CrateContext,
207 name: ast::Name) -> ast::DefId {
208 match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
213 let methods = ccx.tcx.impl_methods.borrow();
214 let methods = methods.find(&impl_id)
215 .expect("could not find impl while translating");
216 let meth_did = methods.iter().find(|&did| ty::method(&ccx.tcx, *did).ident.name == name)
217 .expect("could not find method while translating");
219 ccx.impl_method_cache.borrow_mut().insert((impl_id, name), *meth_did);
223 fn trans_monomorphized_callee<'a>(bcx: &'a Block<'a>,
224 method_call: MethodCall,
225 trait_id: ast::DefId,
227 vtbl: typeck::vtable_origin)
229 let _icx = push_ctxt("meth::trans_monomorphized_callee");
231 typeck::vtable_static(impl_did, rcvr_substs, rcvr_origins) => {
233 let mname = ty::trait_method(ccx.tcx(), trait_id, n_method).ident;
234 let mth_id = method_with_name(bcx.ccx(), impl_did, mname.name);
236 // create a concatenated set of substitutions which includes
237 // those from the impl and those from the method:
238 let (callee_substs, callee_origins) =
239 combine_impl_and_methods_tps(
240 bcx, MethodCall(method_call), rcvr_substs, rcvr_origins);
242 // translate the function
243 let llfn = trans_fn_ref_with_vtables(bcx,
245 MethodCall(method_call),
249 Callee { bcx: bcx, data: Fn(llfn) }
251 typeck::vtable_param(..) => {
253 "vtable_param left in monomorphized function's vtable substs");
255 typeck::vtable_error => {
257 "vtable_error left in monomorphized function's vtable substs");
262 fn combine_impl_and_methods_tps(bcx: &Block,
263 node: ExprOrMethodCall,
264 rcvr_substs: subst::Substs,
265 rcvr_origins: typeck::vtable_res)
266 -> (subst::Substs, typeck::vtable_res)
269 * Creates a concatenated set of substitutions which includes
270 * those from the impl and those from the method. This are
271 * some subtle complications here. Statically, we have a list
272 * of type parameters like `[T0, T1, T2, M1, M2, M3]` where
273 * `Tn` are type parameters that appear on the receiver. For
274 * example, if the receiver is a method parameter `A` with a
275 * bound like `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
277 * The weird part is that the type `A` might now be bound to
278 * any other type, such as `foo<X>`. In that case, the vector
279 * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is
280 * to slice off the method type parameters and append them to
281 * the type parameters from the type that the receiver is
287 let vtable_key = match node {
288 ExprId(id) => MethodCall::expr(id),
289 MethodCall(method_call) => method_call
291 let node_substs = node_id_substs(bcx, node);
292 let node_vtables = node_vtables(bcx, vtable_key);
294 debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
295 debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
297 // Break apart the type parameters from the node and type
298 // parameters from the receiver.
299 let (_, _, node_method) = node_substs.types.split();
300 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_substs.types.clone().split();
301 assert!(rcvr_method.is_empty());
302 let ty_substs = subst::Substs {
303 regions: subst::ErasedRegions,
304 types: subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method)
307 // Now do the same work for the vtables.
308 let (rcvr_type, rcvr_self, rcvr_method) = rcvr_origins.split();
309 let (_, _, node_method) = node_vtables.split();
310 assert!(rcvr_method.is_empty());
311 let vtables = subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method);
316 fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
319 self_expr: &ast::Expr,
320 arg_cleanup_scope: cleanup::ScopeId)
323 * Create a method callee where the method is coming from a trait
324 * object (e.g., Box<Trait> type). In this case, we must pull the fn
325 * pointer out of the vtable that is packaged up with the object.
326 * Objects are represented as a pair, so we first evaluate the self
327 * expression and then extract the self data and vtable out of the
331 let _icx = push_ctxt("meth::trans_trait_callee");
334 // Translate self_datum and take ownership of the value by
335 // converting to an rvalue.
336 let self_datum = unpack_datum!(
337 bcx, expr::trans(bcx, self_expr));
339 let llval = if ty::type_needs_drop(bcx.tcx(), self_datum.ty) {
340 let self_datum = unpack_datum!(
341 bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
343 // Convert to by-ref since `trans_trait_callee_from_llval` wants it
345 let self_datum = unpack_datum!(
346 bcx, self_datum.to_ref_datum(bcx));
348 // Arrange cleanup in case something should go wrong before the
349 // actual call occurs.
350 self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
352 // We don't have to do anything about cleanups for &Trait and &mut Trait.
353 assert!(self_datum.kind.is_by_ref());
357 trans_trait_callee_from_llval(bcx, method_ty, n_method, llval)
360 pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
366 * Same as `trans_trait_callee()` above, except that it is given
367 * a by-ref pointer to the object pair.
370 let _icx = push_ctxt("meth::trans_trait_callee");
373 // Load the data pointer from the object.
374 debug!("(translating trait callee) loading second index from pair");
375 let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
376 let llbox = Load(bcx, llboxptr);
377 let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
379 // Load the function from the vtable and cast it to the expected type.
380 debug!("(translating trait callee) loading method");
381 // Replace the self type (&Self or Box<Self>) with an opaque pointer.
382 let llcallee_ty = match ty::get(callee_ty).sty {
383 ty::ty_bare_fn(ref f) if f.abi == Rust => {
384 type_of_rust_fn(ccx, true, f.sig.inputs.slice_from(1), f.sig.output)
387 ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
390 let llvtable = Load(bcx,
393 [0u, abi::trt_field_vtable]),
394 Type::vtable(ccx).ptr_to().ptr_to()));
395 let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1]));
396 let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
400 data: TraitMethod(MethodData {
407 /// Creates a returns a dynamic vtable for the given type and vtable origin.
408 /// This is used only for objects.
409 fn get_vtable(bcx: &Block,
411 origins: typeck::vtable_param_res)
414 debug!("get_vtable(self_ty={}, origins={})",
415 self_ty.repr(bcx.tcx()),
416 origins.repr(bcx.tcx()));
419 let _icx = push_ctxt("meth::get_vtable");
422 let hash_id = (self_ty, monomorphize::make_vtable_id(ccx, origins.get(0)));
423 match ccx.vtables.borrow().find(&hash_id) {
424 Some(&val) => { return val }
428 // Not in the cache. Actually build it.
429 let methods = origins.move_iter().flat_map(|origin| {
431 typeck::vtable_static(id, substs, sub_vtables) => {
432 emit_vtable_methods(bcx, id, substs, sub_vtables).move_iter()
434 _ => ccx.sess().bug("get_vtable: expected a static origin"),
438 // Generate a destructor for the vtable.
439 let drop_glue = glue::get_drop_glue(ccx, self_ty);
440 let vtable = make_vtable(ccx, drop_glue, methods);
442 ccx.vtables.borrow_mut().insert(hash_id, vtable);
446 /// Helper function to declare and initialize the vtable.
447 pub fn make_vtable<I: Iterator<ValueRef>>(ccx: &CrateContext,
451 let _icx = push_ctxt("meth::make_vtable");
453 let components: Vec<_> = Some(drop_glue).move_iter().chain(ptrs).collect();
456 let tbl = C_struct(ccx, components.as_slice(), false);
457 let sym = token::gensym("vtable");
458 let vt_gvar = format!("vtable{}", sym).with_c_str(|buf| {
459 llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
461 llvm::LLVMSetInitializer(vt_gvar, tbl);
462 llvm::LLVMSetGlobalConstant(vt_gvar, lib::llvm::True);
463 lib::llvm::SetLinkage(vt_gvar, lib::llvm::InternalLinkage);
468 fn emit_vtable_methods(bcx: &Block,
470 substs: subst::Substs,
471 vtables: typeck::vtable_res)
476 let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
477 Some(t_id) => t_id.def_id,
478 None => ccx.sess().bug("make_impl_vtable: don't know how to \
479 make a vtable for a type impl!")
482 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trt_id);
484 let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
485 trait_method_def_ids.iter().map(|method_def_id| {
486 let ident = ty::method(tcx, *method_def_id).ident;
487 // The substitutions we have are on the impl, so we grab
488 // the method type from the impl to substitute into.
489 let m_id = method_with_name(ccx, impl_id, ident.name);
490 let m = ty::method(tcx, m_id);
491 debug!("(making impl vtable) emitting method {} at subst {}",
494 if m.generics.has_type_params(subst::FnSpace) ||
495 ty::type_has_self(ty::mk_bare_fn(tcx, m.fty.clone())) {
496 debug!("(making impl vtable) method has self or type params: {}",
497 token::get_ident(ident));
498 C_null(Type::nil(ccx).ptr_to())
500 let mut fn_ref = trans_fn_ref_with_vtables(bcx,
505 if m.explicit_self == ast::SelfValue {
506 fn_ref = trans_unboxing_shim(bcx,
517 pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
523 * Generates the code to convert from a pointer (`Box<T>`, `&T`, etc)
524 * into an object (`Box<Trait>`, `&Trait`, etc). This means creating a
525 * pair where the first word is the vtable and the second word is
530 let _icx = push_ctxt("meth::trans_cast");
532 let lldest = match dest {
534 return datum.clean(bcx, "trait_cast", id);
541 let llbox_ty = type_of(bcx.ccx(), datum.ty);
543 // Store the pointer into the first half of pair.
544 let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
545 llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
546 bcx = datum.store_to(bcx, llboxdest);
548 // Store the vtable into the second half of pair.
550 let vtable_map = ccx.tcx.vtable_map.borrow();
551 // This trait cast might be because of implicit coercion
552 let method_call = match ccx.tcx.adjustments.borrow().find(&id) {
553 Some(&ty::AutoObject(..)) => MethodCall::autoobject(id),
554 _ => MethodCall::expr(id)
556 let vres = vtable_map.get(&method_call).get_self().unwrap();
557 resolve_param_vtables_under_param_substs(ccx.tcx(), bcx.fcx.param_substs, vres)
559 let vtable = get_vtable(bcx, v_ty, origins);
560 let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
561 let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
562 Store(bcx, vtable, llvtabledest);