// Copyright 2012 The Rust Project Developers. See the COPYRIGHT // file at the top-level directory of this distribution and at // http://rust-lang.org/COPYRIGHT. // // Licensed under the Apache License, Version 2.0 or the MIT license // , at your // option. This file may not be copied, modified, or distributed // except according to those terms. use core::prelude::*; use back::abi; use lib::llvm::llvm; use lib::llvm::ValueRef; use lib; use metadata::csearch; use middle::trans::base::*; use middle::trans::build::*; use middle::trans::callee::*; use middle::trans::callee; use middle::trans::common::*; use middle::trans::expr::{SaveIn, Ignore}; use middle::trans::expr; use middle::trans::glue; use middle::trans::monomorphize; use middle::trans::type_of::*; use middle::ty; use middle::typeck; use util::common::indenter; use util::ppaux::Repr; use middle::trans::type_::Type; use core::vec; use syntax::ast_map::{path, path_mod, path_name}; use syntax::ast_util; use syntax::{ast, ast_map}; /** The main "translation" pass for methods. Generates code for non-monomorphized methods only. Other methods will be generated once they are invoked with specific type parameters, see `trans::base::lval_static_fn()` or `trans::base::monomorphic_fn()`. */ pub fn trans_impl(ccx: @mut CrateContext, path: path, name: ast::ident, methods: &[@ast::method], generics: &ast::Generics, id: ast::node_id) { let _icx = push_ctxt("impl::trans_impl"); let tcx = ccx.tcx; debug!("trans_impl(path=%s, name=%s, id=%?)", path.repr(tcx), name.repr(tcx), id); if !generics.ty_params.is_empty() { return; } let sub_path = vec::append_one(path, path_name(name)); for methods.iter().advance |method| { if method.generics.ty_params.len() == 0u { let llfn = get_item_val(ccx, method.id); let path = vec::append_one(/*bad*/copy sub_path, path_name(method.ident)); trans_method(ccx, path, *method, None, llfn); } } } /** Translates a (possibly monomorphized) method body. # Parameters - `path`: the path to the method - `method`: the AST node for the method - `param_substs`: if this is a generic method, the current values for type parameters and so forth, else none - `llfn`: the LLVM ValueRef for the method - `impl_id`: the node ID of the impl this method is inside */ pub fn trans_method(ccx: @mut CrateContext, path: path, method: &ast::method, param_substs: Option<@param_substs>, llfn: ValueRef) { // figure out how self is being passed let self_arg = match method.explicit_self.node { ast::sty_static => { no_self } _ => { // determine the (monomorphized) type that `self` maps to for // this method let self_ty = ty::node_id_to_type(ccx.tcx, method.self_id); let self_ty = match param_substs { None => self_ty, Some(@param_substs {tys: ref tys, self_ty: ref self_sub, _}) => { ty::subst_tps(ccx.tcx, *tys, *self_sub, self_ty) } }; debug!("calling trans_fn with self_ty %s", self_ty.repr(ccx.tcx)); match method.explicit_self.node { ast::sty_value => impl_owned_self(self_ty), _ => { impl_self(self_ty) } } } }; // generate the actual code trans_fn(ccx, path, &method.decl, &method.body, llfn, self_arg, param_substs, method.id, []); } pub fn trans_self_arg(bcx: block, base: @ast::expr, temp_cleanups: &mut ~[ValueRef], mentry: typeck::method_map_entry) -> Result { let _icx = push_ctxt("impl::trans_self_arg"); // self is passed as an opaque box in the environment slot let self_ty = ty::mk_opaque_box(bcx.tcx()); trans_arg_expr(bcx, self_ty, mentry.self_mode, mentry.explicit_self, base, temp_cleanups, None, DontAutorefArg) } pub fn trans_method_callee(bcx: block, callee_id: ast::node_id, this: @ast::expr, mentry: typeck::method_map_entry) -> Callee { let _icx = push_ctxt("impl::trans_method_callee"); let tcx = bcx.tcx(); debug!("trans_method_callee(callee_id=%?, this=%s, mentry=%s)", callee_id, bcx.expr_to_str(this), mentry.repr(bcx.tcx())); // Replace method_self with method_static here. let mut origin = mentry.origin; match origin { typeck::method_super(trait_id, method_index) => { // is the self type for this method call let self_ty = node_id_type(bcx, this.id); // is the ID of the implementation of // trait for type let impl_id = ty::get_impl_id(tcx, trait_id, self_ty); // Get the supertrait's methods let supertrait_method_def_ids = ty::trait_method_def_ids(tcx, trait_id); // Make sure to fail with a readable error message if // there's some internal error here if !(method_index < supertrait_method_def_ids.len()) { tcx.sess.bug("trans_method_callee: supertrait method \ index is out of bounds"); } // Get the method name using the method index in the origin let method_name = ty::method(tcx, supertrait_method_def_ids[method_index]).ident; // Now that we know the impl ID, we can look up the method // ID from its name origin = typeck::method_static( method_with_name_or_default(bcx.ccx(), impl_id, method_name)); } typeck::method_self(*) | typeck::method_static(*) | typeck::method_param(*) | typeck::method_trait(*) => {} } debug!("origin=%?", origin); match origin { typeck::method_static(did) => { let callee_fn = callee::trans_fn_ref(bcx, did, callee_id); let mut temp_cleanups = ~[]; let Result {bcx, val} = trans_self_arg(bcx, this, &mut temp_cleanups, mentry); Callee { bcx: bcx, data: Method(MethodData { llfn: callee_fn.llfn, llself: val, temp_cleanup: temp_cleanups.head_opt().map(|&v| *v), self_ty: node_id_type(bcx, this.id), self_mode: mentry.self_mode, explicit_self: mentry.explicit_self }) } } typeck::method_param(typeck::method_param { trait_id: trait_id, method_num: off, param_num: p, bound_num: b }) => { match bcx.fcx.param_substs { Some(substs) => { let vtbl = find_vtable(bcx.tcx(), substs, p, b); trans_monomorphized_callee(bcx, callee_id, this, mentry, trait_id, off, vtbl) } // how to get rid of this? None => fail!("trans_method_callee: missing param_substs") } } typeck::method_self(trait_id, method_index) => { match bcx.fcx.param_substs { Some(@param_substs {self_vtable: Some(ref vtbl), _}) => { trans_monomorphized_callee(bcx, callee_id, this, mentry, trait_id, method_index, copy *vtbl) } _ => { fail!("trans_method_callee: missing self_vtable") } } } typeck::method_trait(_, off, store) => { trans_trait_callee(bcx, callee_id, off, this, store, mentry.explicit_self) } typeck::method_super(*) => { fail!("method_super should have been handled above") } } } pub fn trans_static_method_callee(bcx: block, method_id: ast::def_id, trait_id: ast::def_id, callee_id: ast::node_id) -> FnData { let _icx = push_ctxt("impl::trans_static_method_callee"); let ccx = bcx.ccx(); debug!("trans_static_method_callee(method_id=%?, trait_id=%s, \ callee_id=%?)", method_id, ty::item_path_str(bcx.tcx(), trait_id), callee_id); let _indenter = indenter(); // When we translate a static fn defined in a trait like: // // trait Trait { // fn foo(...) {...} // } // // this winds up being translated as something like: // // fn foo,M1...Mn>(...) {...} // // So when we see a call to this function foo, we have to figure // out which impl the `Trait` bound on the type `self` was // bound to. let bound_index = ty::lookup_trait_def(bcx.tcx(), trait_id). generics.type_param_defs.len(); let mname = if method_id.crate == ast::local_crate { match bcx.tcx().items.get_copy(&method_id.node) { ast_map::node_trait_method(trait_method, _, _) => { ast_util::trait_method_to_ty_method(trait_method).ident } _ => fail!("callee is not a trait method") } } else { let path = csearch::get_item_path(bcx.tcx(), method_id); match path[path.len()-1] { path_name(s) => { s } path_mod(_) => { fail!("path doesn't have a name?") } } }; debug!("trans_static_method_callee: method_id=%?, callee_id=%?, \ name=%s", method_id, callee_id, ccx.sess.str_of(mname)); let vtbls = resolve_vtables_in_fn_ctxt( bcx.fcx, ccx.maps.vtable_map.get_copy(&callee_id)); match vtbls[bound_index][0] { typeck::vtable_static(impl_did, ref rcvr_substs, rcvr_origins) => { assert!(rcvr_substs.iter().all(|t| !ty::type_needs_infer(*t))); let mth_id = method_with_name_or_default(bcx.ccx(), impl_did, mname); let (callee_substs, callee_origins) = combine_impl_and_methods_tps( bcx, mth_id, impl_did, callee_id, *rcvr_substs, rcvr_origins); let FnData {llfn: lval} = trans_fn_ref_with_vtables(bcx, mth_id, callee_id, callee_substs, Some(callee_origins)); let callee_ty = node_id_type(bcx, callee_id); let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to(); FnData {llfn: PointerCast(bcx, lval, llty)} } _ => { fail!("vtable_param left in monomorphized \ function's vtable substs"); } } } pub fn method_from_methods(ms: &[@ast::method], name: ast::ident) -> Option { ms.iter().find_(|m| m.ident == name).map(|m| ast_util::local_def(m.id)) } pub fn method_with_name_or_default(ccx: &mut CrateContext, impl_id: ast::def_id, name: ast::ident) -> ast::def_id { let imp = ccx.impl_method_cache.find_copy(&(impl_id, name)); match imp { Some(m) => return m, None => {} } // None of this feels like it should be the best way to do this. let mut did = if impl_id.crate == ast::local_crate { match ccx.tcx.items.get_copy(&impl_id.node) { ast_map::node_item(@ast::item { node: ast::item_impl(_, _, _, ref ms), _ }, _) => { method_from_methods(*ms, name) }, _ => fail!("method_with_name") } } else { csearch::get_impl_method(ccx.sess.cstore, impl_id, name) }; if did.is_none() { // Look for a default method let pmm = ccx.tcx.provided_methods; match pmm.find(&impl_id) { Some(pmis) => { for pmis.iter().advance |pmi| { if pmi.method_info.ident == name { debug!("pmi.method_info.did = %?", pmi.method_info.did); did = Some(pmi.method_info.did); } } } None => {} } } let imp = did.expect("could not find method while translating"); ccx.impl_method_cache.insert((impl_id, name), imp); imp } pub fn method_ty_param_count(ccx: &CrateContext, m_id: ast::def_id, i_id: ast::def_id) -> uint { debug!("method_ty_param_count: m_id: %?, i_id: %?", m_id, i_id); ty::method(ccx.tcx, m_id).generics.type_param_defs.len() } pub fn trans_monomorphized_callee(bcx: block, callee_id: ast::node_id, base: @ast::expr, mentry: typeck::method_map_entry, trait_id: ast::def_id, n_method: uint, vtbl: typeck::vtable_origin) -> Callee { let _icx = push_ctxt("impl::trans_monomorphized_callee"); return match vtbl { typeck::vtable_static(impl_did, ref rcvr_substs, rcvr_origins) => { let ccx = bcx.ccx(); let mname = ty::trait_method(ccx.tcx, trait_id, n_method).ident; let mth_id = method_with_name_or_default( bcx.ccx(), impl_did, mname); // obtain the `self` value: let mut temp_cleanups = ~[]; let Result {bcx, val: llself_val} = trans_self_arg(bcx, base, &mut temp_cleanups, mentry); // create a concatenated set of substitutions which includes // those from the impl and those from the method: let (callee_substs, callee_origins) = combine_impl_and_methods_tps( bcx, mth_id, impl_did, callee_id, *rcvr_substs, rcvr_origins); // translate the function let callee = trans_fn_ref_with_vtables(bcx, mth_id, callee_id, callee_substs, Some(callee_origins)); // create a llvalue that represents the fn ptr let fn_ty = node_id_type(bcx, callee_id); let llfn_ty = type_of_fn_from_ty(ccx, fn_ty).ptr_to(); let llfn_val = PointerCast(bcx, callee.llfn, llfn_ty); // combine the self environment with the rest Callee { bcx: bcx, data: Method(MethodData { llfn: llfn_val, llself: llself_val, temp_cleanup: temp_cleanups.head_opt().map(|&v| *v), self_ty: node_id_type(bcx, base.id), self_mode: mentry.self_mode, explicit_self: mentry.explicit_self }) } } typeck::vtable_param(*) => { fail!("vtable_param left in monomorphized function's vtable substs"); } typeck::vtable_self(*) => { fail!("vtable_self left in monomorphized function's vtable substs"); } }; } pub fn combine_impl_and_methods_tps(bcx: block, mth_did: ast::def_id, impl_did: ast::def_id, callee_id: ast::node_id, rcvr_substs: &[ty::t], rcvr_origins: typeck::vtable_res) -> (~[ty::t], typeck::vtable_res) { /*! * * Creates a concatenated set of substitutions which includes * those from the impl and those from the method. This are * some subtle complications here. Statically, we have a list * of type parameters like `[T0, T1, T2, M1, M2, M3]` where * `Tn` are type parameters that appear on the receiver. For * example, if the receiver is a method parameter `A` with a * bound like `trait` then `Tn` would be `[B,C,D]`. * * The weird part is that the type `A` might now be bound to * any other type, such as `foo`. In that case, the vector * we want is: `[X, M1, M2, M3]`. Therefore, what we do now is * to slice off the method type parameters and append them to * the type parameters from the type that the receiver is * mapped to. */ let ccx = bcx.ccx(); let n_m_tps = method_ty_param_count(ccx, mth_did, impl_did); let node_substs = node_id_type_params(bcx, callee_id); debug!("rcvr_substs=%?", rcvr_substs.map(|t| bcx.ty_to_str(*t))); let ty_substs = vec::append(rcvr_substs.to_owned(), node_substs.tailn(node_substs.len() - n_m_tps)); debug!("n_m_tps=%?", n_m_tps); debug!("node_substs=%?", node_substs.map(|t| bcx.ty_to_str(*t))); debug!("ty_substs=%?", ty_substs.map(|t| bcx.ty_to_str(*t))); // Now, do the same work for the vtables. The vtables might not // exist, in which case we need to make them. let r_m_origins = match node_vtables(bcx, callee_id) { Some(vt) => vt, None => @vec::from_elem(node_substs.len(), @~[]) }; let vtables = @vec::append(rcvr_origins.to_owned(), r_m_origins.tailn(r_m_origins.len() - n_m_tps)); return (ty_substs, vtables); } pub fn trans_trait_callee(bcx: block, callee_id: ast::node_id, n_method: uint, self_expr: @ast::expr, store: ty::TraitStore, explicit_self: ast::explicit_self_) -> Callee { //! // // Create a method callee where the method is coming from a trait // instance (e.g., @Trait type). In this case, we must pull the // fn pointer out of the vtable that is packaged up with the // @/~/&Trait instance. @/~/&Traits are represented as a pair, so we // first evaluate the self expression (expected a by-ref result) and then // extract the self data and vtable out of the pair. let _icx = push_ctxt("impl::trans_trait_callee"); let mut bcx = bcx; let self_datum = unpack_datum!(bcx, expr::trans_to_datum(bcx, self_expr)); let llpair = self_datum.to_ref_llval(bcx); let llpair = match explicit_self { ast::sty_region(*) => Load(bcx, llpair), ast::sty_static | ast::sty_value | ast::sty_box(_) | ast::sty_uniq(_) => llpair }; let callee_ty = node_id_type(bcx, callee_id); trans_trait_callee_from_llval(bcx, callee_ty, n_method, llpair, store, explicit_self) } pub fn trans_trait_callee_from_llval(bcx: block, callee_ty: ty::t, n_method: uint, llpair: ValueRef, store: ty::TraitStore, explicit_self: ast::explicit_self_) -> Callee { //! // // Same as `trans_trait_callee()` above, except that it is given // a by-ref pointer to the @Trait pair. let _icx = push_ctxt("impl::trans_trait_callee"); let ccx = bcx.ccx(); let mut bcx = bcx; // Load the vtable from the @Trait pair debug!("(translating trait callee) loading vtable from pair %s", bcx.val_to_str(llpair)); let llvtable = Load(bcx, PointerCast(bcx, GEPi(bcx, llpair, [0u, abi::trt_field_vtable]), Type::vtable().ptr_to().ptr_to())); // Load the box from the @Trait pair and GEP over the box header if // necessary: let mut llself; debug!("(translating trait callee) loading second index from pair"); let llbox = Load(bcx, GEPi(bcx, llpair, [0u, abi::trt_field_box])); // Munge `llself` appropriately for the type of `self` in the method. match explicit_self { ast::sty_static => { bcx.tcx().sess.bug("shouldn't see static method here"); } ast::sty_value => { bcx.tcx().sess.bug("methods with by-value self should not be \ called on objects"); } ast::sty_region(*) => { // As before, we need to pass a pointer to a pointer to the // payload. match store { ty::BoxTraitStore | ty::UniqTraitStore => { llself = GEPi(bcx, llbox, [0u, abi::box_field_body]); } ty::RegionTraitStore(_) => { llself = llbox; } } } ast::sty_box(_) => { // Bump the reference count on the box. debug!("(translating trait callee) callee type is `%s`", bcx.ty_to_str(callee_ty)); bcx = glue::take_ty(bcx, llbox, callee_ty); // Pass a pointer to the box. match store { ty::BoxTraitStore => llself = llbox, _ => bcx.tcx().sess.bug("@self receiver with non-@Trait") } } ast::sty_uniq(_) => { // Pass the unique pointer. match store { ty::UniqTraitStore => llself = llbox, _ => bcx.tcx().sess.bug("~self receiver with non-~Trait") } } } let llscratch = alloca(bcx, val_ty(llself)); Store(bcx, llself, llscratch); llself = PointerCast(bcx, llscratch, Type::opaque_box(ccx).ptr_to()); // Load the function from the vtable and cast it to the expected type. debug!("(translating trait callee) loading method"); let llcallee_ty = type_of_fn_from_ty(ccx, callee_ty); // Plus one in order to skip past the type descriptor. let mptr = Load(bcx, GEPi(bcx, llvtable, [0u, n_method + 1])); let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to()); return Callee { bcx: bcx, data: Method(MethodData { llfn: mptr, llself: llself, temp_cleanup: None, self_ty: ty::mk_opaque_box(bcx.tcx()), self_mode: ty::ByRef, explicit_self: explicit_self /* XXX: Some(llbox) */ }) }; } pub fn vtable_id(ccx: @mut CrateContext, origin: &typeck::vtable_origin) -> mono_id { match origin { &typeck::vtable_static(impl_id, ref substs, sub_vtables) => { monomorphize::make_mono_id( ccx, impl_id, *substs, if sub_vtables.is_empty() { None } else { Some(sub_vtables) }, None, None) } // can't this be checked at the callee? _ => fail!("vtable_id") } } /// Creates a returns a dynamic vtable for the given type and vtable origin. /// This is used only for objects. pub fn get_vtable(bcx: block, self_ty: ty::t, origin: typeck::vtable_origin) -> ValueRef { let hash_id = vtable_id(bcx.ccx(), &origin); match bcx.ccx().vtables.find(&hash_id) { Some(&val) => val, None => { match origin { typeck::vtable_static(id, substs, sub_vtables) => { make_impl_vtable(bcx, id, self_ty, substs, sub_vtables) } _ => fail!("get_vtable: expected a static origin"), } } } } /// Helper function to declare and initialize the vtable. pub fn make_vtable(ccx: &mut CrateContext, tydesc: &tydesc_info, ptrs: &[ValueRef]) -> ValueRef { unsafe { let _icx = push_ctxt("impl::make_vtable"); let mut components = ~[ tydesc.tydesc ]; for ptrs.iter().advance |&ptr| { components.push(ptr) } let tbl = C_struct(components); let vtable = ccx.sess.str_of(gensym_name("vtable")); let vt_gvar = do vtable.as_c_str |buf| { llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf) }; llvm::LLVMSetInitializer(vt_gvar, tbl); llvm::LLVMSetGlobalConstant(vt_gvar, lib::llvm::True); lib::llvm::SetLinkage(vt_gvar, lib::llvm::InternalLinkage); vt_gvar } } /// Generates a dynamic vtable for objects. pub fn make_impl_vtable(bcx: block, impl_id: ast::def_id, self_ty: ty::t, substs: &[ty::t], vtables: typeck::vtable_res) -> ValueRef { let ccx = bcx.ccx(); let _icx = push_ctxt("impl::make_impl_vtable"); let tcx = ccx.tcx; let trt_id = match ty::impl_trait_ref(tcx, impl_id) { Some(t_id) => t_id.def_id, None => ccx.sess.bug("make_impl_vtable: don't know how to \ make a vtable for a type impl!") }; let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id); let methods = do trait_method_def_ids.map |method_def_id| { let im = ty::method(tcx, *method_def_id); let fty = ty::subst_tps(tcx, substs, None, ty::mk_bare_fn(tcx, copy im.fty)); if im.generics.has_type_params() || ty::type_has_self(fty) { debug!("(making impl vtable) method has self or type params: %s", tcx.sess.str_of(im.ident)); C_null(Type::nil().ptr_to()) } else { debug!("(making impl vtable) adding method to vtable: %s", tcx.sess.str_of(im.ident)); let m_id = method_with_name_or_default(ccx, impl_id, im.ident); trans_fn_ref_with_vtables(bcx, m_id, 0, substs, Some(vtables)).llfn } }; // Generate a type descriptor for the vtable. let tydesc = get_tydesc(ccx, self_ty); glue::lazily_emit_all_tydesc_glue(ccx, tydesc); make_vtable(ccx, tydesc, methods) } pub fn trans_trait_cast(bcx: block, val: @ast::expr, id: ast::node_id, dest: expr::Dest, _store: ty::TraitStore) -> block { let mut bcx = bcx; let _icx = push_ctxt("impl::trans_cast"); let lldest = match dest { Ignore => { return expr::trans_into(bcx, val, Ignore); } SaveIn(dest) => dest }; let ccx = bcx.ccx(); let v_ty = expr_ty(bcx, val); let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]); // Just store the pointer into the pair. (Region/borrowed // and boxed trait objects are represented as pairs, and // have no type descriptor field.) llboxdest = PointerCast(bcx, llboxdest, type_of(bcx.ccx(), v_ty).ptr_to()); bcx = expr::trans_into(bcx, val, SaveIn(llboxdest)); // Store the vtable into the pair or triple. let orig = /*bad*/copy ccx.maps.vtable_map.get(&id)[0][0]; let orig = resolve_vtable_in_fn_ctxt(bcx.fcx, orig); let vtable = get_vtable(bcx, v_ty, orig); Store(bcx, vtable, PointerCast(bcx, GEPi(bcx, lldest, [0u, abi::trt_field_vtable]), val_ty(vtable).ptr_to())); bcx }