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;
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 /// Translates a (possibly monomorphized) method body.
81 /// * `method`: the AST node for the method
82 /// * `param_substs`: if this is a generic method, the current values for
83 /// type parameters and so forth, else None
84 /// * `llfn`: the LLVM ValueRef for the method
86 pub fn trans_method(ccx: &CrateContext, method: &ast::Method,
87 param_substs: Option<@param_substs>,
88 llfn: ValueRef) -> ValueRef {
89 trans_fn(ccx, method.decl, method.body,
90 llfn, param_substs, method.id, []);
94 pub fn trans_method_callee<'a>(
96 method_call: MethodCall,
97 self_expr: Option<&ast::Expr>,
98 arg_cleanup_scope: cleanup::ScopeId)
100 let _icx = push_ctxt("meth::trans_method_callee");
102 let (origin, method_ty) = match bcx.ccx().maps.method_map
103 .borrow().find(&method_call) {
105 debug!("trans_method_callee({:?}, method={})",
106 method_call, method.repr(bcx.tcx()));
107 (method.origin, method.ty)
110 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
111 "method call expr wasn't in method map")
116 typeck::MethodStatic(did) => {
119 data: Fn(callee::trans_fn_ref(bcx, did, MethodCall(method_call)))
122 typeck::MethodParam(typeck::MethodParam {
128 match bcx.fcx.param_substs {
130 ty::populate_implementations_for_trait_if_necessary(
134 let vtbl = find_vtable(bcx.tcx(), substs, p, b);
135 trans_monomorphized_callee(bcx, method_call,
138 // how to get rid of this?
139 None => fail!("trans_method_callee: missing param_substs")
143 typeck::MethodObject(ref mt) => {
144 let self_expr = match self_expr {
145 Some(self_expr) => self_expr,
147 bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
148 "self expr wasn't provided for trait object \
149 callee (trying to call overloaded op?)")
152 trans_trait_callee(bcx,
153 monomorphize_type(bcx, method_ty),
161 pub fn trans_static_method_callee(bcx: &Block,
162 method_id: ast::DefId,
163 trait_id: ast::DefId,
164 expr_id: ast::NodeId)
166 let _icx = push_ctxt("meth::trans_static_method_callee");
169 debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
172 ty::item_path_str(bcx.tcx(), trait_id),
174 let _indenter = indenter();
176 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
178 // When we translate a static fn defined in a trait like:
180 // trait<T1...Tn> Trait {
181 // fn foo<M1...Mn>(...) {...}
184 // this winds up being translated as something like:
186 // fn foo<T1...Tn,self: Trait<T1...Tn>,M1...Mn>(...) {...}
188 // So when we see a call to this function foo, we have to figure
189 // out which impl the `Trait<T1...Tn>` bound on the type `self` was
191 let bound_index = ty::lookup_trait_def(bcx.tcx(), trait_id).
192 generics.type_param_defs().len();
194 let mname = if method_id.krate == ast::LOCAL_CRATE {
195 match bcx.tcx().map.get(method_id.node) {
196 ast_map::NodeTraitMethod(method) => {
197 let ident = match *method {
198 ast::Required(ref m) => m.ident,
199 ast::Provided(ref m) => m.ident
203 _ => fail!("callee is not a trait method")
206 csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
208 debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
209 name={}", method_id, expr_id, token::get_name(mname));
211 let vtable_key = MethodCall::expr(expr_id);
212 let vtbls = ccx.maps.vtable_map.borrow().get_copy(&vtable_key);
213 let vtbls = resolve_vtables_in_fn_ctxt(bcx.fcx, vtbls);
215 match vtbls.get(bound_index).get(0) {
216 &typeck::vtable_static(impl_did, ref rcvr_substs, rcvr_origins) => {
217 assert!(rcvr_substs.iter().all(|t| !ty::type_needs_infer(*t)));
219 let mth_id = method_with_name(ccx, impl_did, mname);
220 let (callee_substs, callee_origins) =
221 combine_impl_and_methods_tps(
222 bcx, mth_id, ExprId(expr_id),
223 rcvr_substs.as_slice(), rcvr_origins);
225 let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
226 callee_substs.as_slice(),
227 Some(callee_origins));
229 let callee_ty = node_id_type(bcx, expr_id);
230 let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
231 PointerCast(bcx, llfn, llty)
234 fail!("vtable_param left in monomorphized \
235 function's vtable substs");
240 pub fn method_with_name(ccx: &CrateContext,
242 name: ast::Name) -> ast::DefId {
243 match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
248 let imp = ccx.tcx.impls.borrow();
249 let imp = imp.find(&impl_id)
250 .expect("could not find impl while translating");
251 let meth = imp.methods.iter().find(|m| m.ident.name == name)
252 .expect("could not find method while translating");
254 ccx.impl_method_cache.borrow_mut().insert((impl_id, name), meth.def_id);
258 fn trans_monomorphized_callee<'a>(bcx: &'a Block<'a>,
259 method_call: MethodCall,
260 trait_id: ast::DefId,
262 vtbl: typeck::vtable_origin)
264 let _icx = push_ctxt("meth::trans_monomorphized_callee");
266 typeck::vtable_static(impl_did, ref rcvr_substs, rcvr_origins) => {
268 let mname = ty::trait_method(ccx.tcx(), trait_id, n_method).ident;
269 let mth_id = method_with_name(bcx.ccx(), impl_did, mname.name);
271 // create a concatenated set of substitutions which includes
272 // those from the impl and those from the method:
273 let (callee_substs, callee_origins) =
274 combine_impl_and_methods_tps(
275 bcx, mth_id, MethodCall(method_call),
276 rcvr_substs.as_slice(), rcvr_origins);
278 // translate the function
279 let llfn = trans_fn_ref_with_vtables(bcx,
281 MethodCall(method_call),
282 callee_substs.as_slice(),
283 Some(callee_origins));
285 Callee { bcx: bcx, data: Fn(llfn) }
287 typeck::vtable_param(..) => {
288 fail!("vtable_param left in monomorphized function's vtable substs");
293 fn combine_impl_and_methods_tps(bcx: &Block,
295 node: ExprOrMethodCall,
296 rcvr_substs: &[ty::t],
297 rcvr_origins: typeck::vtable_res)
298 -> (Vec<ty::t> , typeck::vtable_res) {
301 * Creates a concatenated set of substitutions which includes
302 * those from the impl and those from the method. This are
303 * some subtle complications here. Statically, we have a list
304 * of type parameters like `[T0, T1, T2, M1, M2, M3]` where
305 * `Tn` are type parameters that appear on the receiver. For
306 * example, if the receiver is a method parameter `A` with a
307 * bound like `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
309 * The weird part is that the type `A` might now be bound to
310 * any other type, such as `foo<X>`. In that case, the vector
311 * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is
312 * to slice off the method type parameters and append them to
313 * the type parameters from the type that the receiver is
317 let method = ty::method(ccx.tcx(), mth_did);
318 let n_m_tps = method.generics.type_param_defs().len();
319 let node_substs = node_id_type_params(bcx, node);
320 debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
322 = vec::append(Vec::from_slice(rcvr_substs),
323 node_substs.tailn(node_substs.len() - n_m_tps));
324 debug!("n_m_tps={:?}", n_m_tps);
325 debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
326 debug!("ty_substs={:?}", ty_substs.repr(ccx.tcx()));
329 // Now, do the same work for the vtables. The vtables might not
330 // exist, in which case we need to make them.
331 let vtable_key = match node {
332 ExprId(id) => MethodCall::expr(id),
333 MethodCall(method_call) => method_call
335 let vtables = node_vtables(bcx, vtable_key);
336 let r_m_origins = match vtables {
338 None => @Vec::from_elem(node_substs.len(), @Vec::new())
341 = @vec::append(Vec::from_slice(rcvr_origins.as_slice()),
342 r_m_origins.tailn(r_m_origins.len() - n_m_tps));
347 fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
350 self_expr: &ast::Expr,
351 arg_cleanup_scope: cleanup::ScopeId)
354 * Create a method callee where the method is coming from a trait
355 * object (e.g., ~Trait type). In this case, we must pull the fn
356 * pointer out of the vtable that is packaged up with the object.
357 * Objects are represented as a pair, so we first evaluate the self
358 * expression and then extract the self data and vtable out of the
362 let _icx = push_ctxt("meth::trans_trait_callee");
365 // Translate self_datum and take ownership of the value by
366 // converting to an rvalue.
367 let self_datum = unpack_datum!(
368 bcx, expr::trans(bcx, self_expr));
370 let llval = if ty::type_needs_drop(bcx.tcx(), self_datum.ty) {
371 let self_datum = unpack_datum!(
372 bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
374 // Convert to by-ref since `trans_trait_callee_from_llval` wants it
376 let self_datum = unpack_datum!(
377 bcx, self_datum.to_ref_datum(bcx));
379 // Arrange cleanup in case something should go wrong before the
380 // actual call occurs.
381 self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
383 // We don't have to do anything about cleanups for &Trait and &mut Trait.
384 assert!(self_datum.kind.is_by_ref());
388 trans_trait_callee_from_llval(bcx, method_ty, n_method, llval)
391 pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
397 * Same as `trans_trait_callee()` above, except that it is given
398 * a by-ref pointer to the object pair.
401 let _icx = push_ctxt("meth::trans_trait_callee");
404 // Load the data pointer from the object.
405 debug!("(translating trait callee) loading second index from pair");
406 let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
407 let llbox = Load(bcx, llboxptr);
408 let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
410 // Load the function from the vtable and cast it to the expected type.
411 debug!("(translating trait callee) loading method");
412 // Replace the self type (&Self or ~Self) with an opaque pointer.
413 let llcallee_ty = match ty::get(callee_ty).sty {
414 ty::ty_bare_fn(ref f) if f.abis.is_rust() => {
415 type_of_rust_fn(ccx, true, f.sig.inputs.slice_from(1), f.sig.output)
418 ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
421 let llvtable = Load(bcx,
424 [0u, abi::trt_field_vtable]),
425 Type::vtable(ccx).ptr_to().ptr_to()));
426 let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1]));
427 let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
431 data: TraitMethod(MethodData {
438 pub fn vtable_id(ccx: &CrateContext,
439 origin: &typeck::vtable_origin)
442 &typeck::vtable_static(impl_id, ref substs, sub_vtables) => {
443 let psubsts = param_substs {
444 tys: (*substs).clone(),
445 vtables: Some(sub_vtables),
450 monomorphize::make_mono_id(
456 // can't this be checked at the callee?
457 _ => fail!("vtable_id")
461 /// Creates a returns a dynamic vtable for the given type and vtable origin.
462 /// This is used only for objects.
463 pub fn get_vtable(bcx: &Block,
465 origins: typeck::vtable_param_res)
468 let _icx = push_ctxt("meth::get_vtable");
471 let hash_id = (self_ty, vtable_id(ccx, origins.get(0)));
472 match ccx.vtables.borrow().find(&hash_id) {
473 Some(&val) => { return val }
477 // Not in the cache. Actually build it.
478 let mut methods = Vec::new();
479 for origin in origins.iter() {
481 typeck::vtable_static(id, ref substs, sub_vtables) => {
482 let vtable_methods = emit_vtable_methods(bcx,
486 for vtable_method in vtable_methods.move_iter() {
487 methods.push(vtable_method)
490 _ => ccx.sess().bug("get_vtable: expected a static origin"),
494 // Generate a destructor for the vtable.
495 let drop_glue = glue::get_drop_glue(ccx, self_ty);
496 let vtable = make_vtable(ccx, drop_glue, methods.as_slice());
498 ccx.vtables.borrow_mut().insert(hash_id, vtable);
502 /// Helper function to declare and initialize the vtable.
503 pub fn make_vtable(ccx: &CrateContext,
508 let _icx = push_ctxt("meth::make_vtable");
510 let mut components = vec!(drop_glue);
511 for &ptr in ptrs.iter() {
515 let tbl = C_struct(ccx, components.as_slice(), false);
516 let sym = token::gensym("vtable");
517 let vt_gvar = format!("vtable{}", sym).with_c_str(|buf| {
518 llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
520 llvm::LLVMSetInitializer(vt_gvar, tbl);
521 llvm::LLVMSetGlobalConstant(vt_gvar, lib::llvm::True);
522 lib::llvm::SetLinkage(vt_gvar, lib::llvm::InternalLinkage);
527 fn emit_vtable_methods(bcx: &Block,
530 vtables: typeck::vtable_res)
535 let trt_id = match ty::impl_trait_ref(tcx, impl_id) {
536 Some(t_id) => t_id.def_id,
537 None => ccx.sess().bug("make_impl_vtable: don't know how to \
538 make a vtable for a type impl!")
541 ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trt_id);
543 let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
544 trait_method_def_ids.map(|method_def_id| {
545 let ident = ty::method(tcx, *method_def_id).ident;
546 // The substitutions we have are on the impl, so we grab
547 // the method type from the impl to substitute into.
548 let m_id = method_with_name(ccx, impl_id, ident.name);
549 let m = ty::method(tcx, m_id);
550 debug!("(making impl vtable) emitting method {} at subst {}",
553 if m.generics.has_type_params() ||
554 ty::type_has_self(ty::mk_bare_fn(tcx, m.fty.clone())) {
555 debug!("(making impl vtable) method has self or type params: {}",
556 token::get_ident(ident));
557 C_null(Type::nil(ccx).ptr_to())
559 trans_fn_ref_with_vtables(bcx, m_id, ExprId(0), substs, Some(vtables))
564 pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
570 * Generates the code to convert from a pointer (`~T`, `&T`, etc)
571 * into an object (`~Trait`, `&Trait`, etc). This means creating a
572 * pair where the first word is the vtable and the second word is
577 let _icx = push_ctxt("meth::trans_cast");
579 let lldest = match dest {
581 return datum.clean(bcx, "trait_cast", id);
588 let llbox_ty = type_of(bcx.ccx(), datum.ty);
590 // Store the pointer into the first half of pair.
591 let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
592 llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
593 bcx = datum.store_to(bcx, llboxdest);
595 // Store the vtable into the second half of pair.
596 let res = *ccx.maps.vtable_map.borrow().get(&MethodCall::expr(id));
597 let origins = *resolve_vtables_in_fn_ctxt(bcx.fcx, res).get(0);
598 let vtable = get_vtable(bcx, v_ty, origins);
599 let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
600 let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
601 Store(bcx, vtable, llvtabledest);