b79a788f8f
... objects For method calls through trait objects, we currently generate the llvm function argument attributes using the non-opaque method signature that still has the trait object fat pointer for the self pointer. This leads to attributes that are plain wrong, e.g. noalias. As we don't know anything about the concrete type of the underlying object, we must replace the self argument with an opaque i8 pointer before applying the attributes.
887 lines
35 KiB
Rust
887 lines
35 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use arena::TypedArena;
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use back::abi;
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use back::link;
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use llvm::{ValueRef, get_param};
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use metadata::csearch;
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use middle::subst::Substs;
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use middle::subst::VecPerParamSpace;
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use middle::subst;
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use middle::traits;
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use trans::base::*;
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use trans::build::*;
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use trans::callee::*;
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use trans::callee;
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use trans::cleanup;
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use trans::common::*;
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use trans::consts;
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use trans::datum::*;
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use trans::debuginfo::DebugLoc;
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use trans::expr::{SaveIn, Ignore};
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use trans::expr;
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use trans::glue;
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use trans::machine;
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use trans::monomorphize;
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use trans::type_::Type;
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use trans::type_of::*;
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use middle::ty::{self, Ty};
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use middle::ty::MethodCall;
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use util::ppaux::Repr;
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use std::rc::Rc;
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use syntax::abi::{Rust, RustCall};
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use syntax::parse::token;
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use syntax::{ast, ast_map, attr, visit};
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use syntax::ast_util::PostExpansionMethod;
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use syntax::codemap::DUMMY_SP;
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// drop_glue pointer, size, align.
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static VTABLE_OFFSET: uint = 3;
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/// The main "translation" pass for methods. Generates code
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/// for non-monomorphized methods only. Other methods will
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/// be generated once they are invoked with specific type parameters,
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/// see `trans::base::lval_static_fn()` or `trans::base::monomorphic_fn()`.
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pub fn trans_impl(ccx: &CrateContext,
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name: ast::Ident,
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impl_items: &[ast::ImplItem],
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generics: &ast::Generics,
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id: ast::NodeId) {
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let _icx = push_ctxt("meth::trans_impl");
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let tcx = ccx.tcx();
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debug!("trans_impl(name={}, id={})", name.repr(tcx), id);
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// Both here and below with generic methods, be sure to recurse and look for
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// items that we need to translate.
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if !generics.ty_params.is_empty() {
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let mut v = TransItemVisitor{ ccx: ccx };
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for impl_item in impl_items {
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match *impl_item {
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ast::MethodImplItem(ref method) => {
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visit::walk_method_helper(&mut v, &**method);
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}
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ast::TypeImplItem(_) => {}
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}
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}
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return;
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}
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for impl_item in impl_items {
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match *impl_item {
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ast::MethodImplItem(ref method) => {
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if method.pe_generics().ty_params.len() == 0 {
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let trans_everywhere = attr::requests_inline(&method.attrs);
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for (ref ccx, is_origin) in ccx.maybe_iter(trans_everywhere) {
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let llfn = get_item_val(ccx, method.id);
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let empty_substs = tcx.mk_substs(Substs::trans_empty());
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trans_fn(ccx,
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method.pe_fn_decl(),
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method.pe_body(),
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llfn,
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empty_substs,
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method.id,
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&[]);
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update_linkage(ccx,
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llfn,
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Some(method.id),
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if is_origin { OriginalTranslation } else { InlinedCopy });
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}
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}
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let mut v = TransItemVisitor {
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ccx: ccx,
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};
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visit::walk_method_helper(&mut v, &**method);
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}
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ast::TypeImplItem(_) => {}
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}
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}
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}
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pub fn trans_method_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
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method_call: MethodCall,
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self_expr: Option<&ast::Expr>,
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arg_cleanup_scope: cleanup::ScopeId)
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-> Callee<'blk, 'tcx> {
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let _icx = push_ctxt("meth::trans_method_callee");
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let (origin, method_ty) =
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bcx.tcx().method_map
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.borrow()
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.get(&method_call)
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.map(|method| (method.origin.clone(), method.ty))
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.unwrap();
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match origin {
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ty::MethodStatic(did) |
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ty::MethodStaticClosure(did) => {
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Callee {
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bcx: bcx,
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data: Fn(callee::trans_fn_ref(bcx.ccx(),
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did,
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MethodCallKey(method_call),
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bcx.fcx.param_substs).val),
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}
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}
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ty::MethodTypeParam(ty::MethodParam {
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ref trait_ref,
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method_num,
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impl_def_id: _
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}) => {
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let trait_ref = ty::Binder(bcx.monomorphize(trait_ref));
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let span = bcx.tcx().map.span(method_call.expr_id);
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debug!("method_call={:?} trait_ref={}",
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method_call,
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trait_ref.repr(bcx.tcx()));
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let origin = fulfill_obligation(bcx.ccx(),
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span,
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trait_ref.clone());
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debug!("origin = {}", origin.repr(bcx.tcx()));
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trans_monomorphized_callee(bcx,
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method_call,
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trait_ref.def_id(),
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method_num,
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origin)
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}
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ty::MethodTraitObject(ref mt) => {
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let self_expr = match self_expr {
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Some(self_expr) => self_expr,
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None => {
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bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
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"self expr wasn't provided for trait object \
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callee (trying to call overloaded op?)")
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}
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};
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trans_trait_callee(bcx,
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monomorphize_type(bcx, method_ty),
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mt.vtable_index,
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self_expr,
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arg_cleanup_scope)
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}
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}
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}
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pub fn trans_static_method_callee<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
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method_id: ast::DefId,
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trait_id: ast::DefId,
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expr_id: ast::NodeId,
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param_substs: &'tcx subst::Substs<'tcx>)
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-> Datum<'tcx, Rvalue>
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{
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let _icx = push_ctxt("meth::trans_static_method_callee");
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let tcx = ccx.tcx();
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debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
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expr_id={})",
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method_id,
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ty::item_path_str(tcx, trait_id),
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expr_id);
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let mname = if method_id.krate == ast::LOCAL_CRATE {
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match tcx.map.get(method_id.node) {
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ast_map::NodeTraitItem(method) => {
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let ident = match *method {
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ast::RequiredMethod(ref m) => m.ident,
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ast::ProvidedMethod(ref m) => m.pe_ident(),
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ast::TypeTraitItem(_) => {
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tcx.sess.bug("trans_static_method_callee() on \
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an associated type?!")
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}
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};
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ident.name
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}
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_ => panic!("callee is not a trait method")
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}
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} else {
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csearch::get_item_path(tcx, method_id).last().unwrap().name()
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};
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debug!("trans_static_method_callee: method_id={:?}, expr_id={}, \
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name={}", method_id, expr_id, token::get_name(mname));
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// Find the substitutions for the fn itself. This includes
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// type parameters that belong to the trait but also some that
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// belong to the method:
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let rcvr_substs = node_id_substs(ccx, ExprId(expr_id), param_substs);
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let subst::SeparateVecsPerParamSpace {
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types: rcvr_type,
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selfs: rcvr_self,
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fns: rcvr_method
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} = rcvr_substs.types.split();
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// Lookup the precise impl being called. To do that, we need to
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// create a trait reference identifying the self type and other
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// input type parameters. To create that trait reference, we have
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// to pick apart the type parameters to identify just those that
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// pertain to the trait. This is easiest to explain by example:
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//
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// trait Convert {
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// fn from<U:Foo>(n: U) -> Option<Self>;
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// }
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// ...
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// let f = <Vec<int> as Convert>::from::<String>(...)
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//
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// Here, in this call, which I've written with explicit UFCS
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// notation, the set of type parameters will be:
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//
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// rcvr_type: [] <-- nothing declared on the trait itself
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// rcvr_self: [Vec<int>] <-- the self type
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// rcvr_method: [String] <-- method type parameter
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//
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// So we create a trait reference using the first two,
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// basically corresponding to `<Vec<int> as Convert>`.
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// The remaining type parameters (`rcvr_method`) will be used below.
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let trait_substs =
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Substs::erased(VecPerParamSpace::new(rcvr_type,
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rcvr_self,
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Vec::new()));
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let trait_substs = tcx.mk_substs(trait_substs);
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debug!("trait_substs={}", trait_substs.repr(tcx));
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let trait_ref = ty::Binder(Rc::new(ty::TraitRef { def_id: trait_id,
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substs: trait_substs }));
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let vtbl = fulfill_obligation(ccx,
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DUMMY_SP,
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trait_ref);
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// Now that we know which impl is being used, we can dispatch to
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// the actual function:
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match vtbl {
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traits::VtableImpl(traits::VtableImplData {
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impl_def_id: impl_did,
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substs: impl_substs,
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nested: _ }) =>
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{
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assert!(impl_substs.types.all(|t| !ty::type_needs_infer(*t)));
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// Create the substitutions that are in scope. This combines
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// the type parameters from the impl with those declared earlier.
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// To see what I mean, consider a possible impl:
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//
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// impl<T> Convert for Vec<T> {
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// fn from<U:Foo>(n: U) { ... }
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// }
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//
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// Recall that we matched `<Vec<int> as Convert>`. Trait
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// resolution will have given us a substitution
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// containing `impl_substs=[[T=int],[],[]]` (the type
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// parameters defined on the impl). We combine
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// that with the `rcvr_method` from before, which tells us
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// the type parameters from the *method*, to yield
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// `callee_substs=[[T=int],[],[U=String]]`.
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let subst::SeparateVecsPerParamSpace {
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types: impl_type,
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selfs: impl_self,
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fns: _
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} = impl_substs.types.split();
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let callee_substs =
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Substs::erased(VecPerParamSpace::new(impl_type,
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impl_self,
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rcvr_method));
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let mth_id = method_with_name(ccx, impl_did, mname);
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trans_fn_ref_with_substs(ccx, mth_id, ExprId(expr_id),
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param_substs,
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callee_substs)
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}
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traits::VtableObject(ref data) => {
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let trait_item_def_ids =
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ty::trait_item_def_ids(ccx.tcx(), trait_id);
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let method_offset_in_trait =
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trait_item_def_ids.iter()
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.position(|item| item.def_id() == method_id)
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.unwrap();
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let (llfn, ty) =
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trans_object_shim(ccx, data.object_ty, trait_id, method_offset_in_trait);
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immediate_rvalue(llfn, ty)
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}
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_ => {
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tcx.sess.bug(&format!("static call to invalid vtable: {}",
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vtbl.repr(tcx)));
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}
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}
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}
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fn method_with_name(ccx: &CrateContext, impl_id: ast::DefId, name: ast::Name)
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-> ast::DefId {
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match ccx.impl_method_cache().borrow().get(&(impl_id, name)).cloned() {
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Some(m) => return m,
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None => {}
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}
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let impl_items = ccx.tcx().impl_items.borrow();
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let impl_items =
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impl_items.get(&impl_id)
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.expect("could not find impl while translating");
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let meth_did = impl_items.iter()
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.find(|&did| {
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ty::impl_or_trait_item(ccx.tcx(), did.def_id()).name() == name
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}).expect("could not find method while \
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translating");
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ccx.impl_method_cache().borrow_mut().insert((impl_id, name),
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meth_did.def_id());
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meth_did.def_id()
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}
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fn trans_monomorphized_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
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method_call: MethodCall,
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trait_id: ast::DefId,
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n_method: uint,
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vtable: traits::Vtable<'tcx, ()>)
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-> Callee<'blk, 'tcx> {
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let _icx = push_ctxt("meth::trans_monomorphized_callee");
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match vtable {
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traits::VtableImpl(vtable_impl) => {
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let ccx = bcx.ccx();
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let impl_did = vtable_impl.impl_def_id;
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let mname = match ty::trait_item(ccx.tcx(), trait_id, n_method) {
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ty::MethodTraitItem(method) => method.name,
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ty::TypeTraitItem(_) => {
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bcx.tcx().sess.bug("can't monomorphize an associated \
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type")
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}
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};
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let mth_id = method_with_name(bcx.ccx(), impl_did, mname);
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// create a concatenated set of substitutions which includes
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// those from the impl and those from the method:
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let callee_substs =
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combine_impl_and_methods_tps(
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bcx, MethodCallKey(method_call), vtable_impl.substs);
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// translate the function
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let llfn = trans_fn_ref_with_substs(bcx.ccx(),
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mth_id,
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MethodCallKey(method_call),
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bcx.fcx.param_substs,
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callee_substs).val;
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Callee { bcx: bcx, data: Fn(llfn) }
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}
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traits::VtableClosure(closure_def_id, substs) => {
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// The substitutions should have no type parameters remaining
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// after passing through fulfill_obligation
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let llfn = trans_fn_ref_with_substs(bcx.ccx(),
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closure_def_id,
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MethodCallKey(method_call),
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bcx.fcx.param_substs,
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substs).val;
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Callee {
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bcx: bcx,
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data: Fn(llfn),
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}
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}
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traits::VtableFnPointer(fn_ty) => {
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let llfn = trans_fn_pointer_shim(bcx.ccx(), fn_ty);
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Callee { bcx: bcx, data: Fn(llfn) }
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}
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traits::VtableObject(ref data) => {
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let (llfn, _) = trans_object_shim(bcx.ccx(), data.object_ty, trait_id, n_method);
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Callee { bcx: bcx, data: Fn(llfn) }
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}
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traits::VtableBuiltin(..) |
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traits::VtableDefaultImpl(..) |
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traits::VtableParam(..) => {
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bcx.sess().bug(
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&format!("resolved vtable bad vtable {} in trans",
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vtable.repr(bcx.tcx())));
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}
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}
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}
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/// Creates a concatenated set of substitutions which includes those from the impl and those from
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/// the method. This are some subtle complications here. Statically, we have a list of type
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/// parameters like `[T0, T1, T2, M1, M2, M3]` where `Tn` are type parameters that appear on the
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/// receiver. For example, if the receiver is a method parameter `A` with a bound like
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/// `trait<B,C,D>` then `Tn` would be `[B,C,D]`.
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///
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/// The weird part is that the type `A` might now be bound to any other type, such as `foo<X>`.
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/// In that case, the vector we want is: `[X, M1, M2, M3]`. Therefore, what we do now is to slice
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/// off the method type parameters and append them to the type parameters from the type that the
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/// receiver is mapped to.
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fn combine_impl_and_methods_tps<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
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node: ExprOrMethodCall,
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rcvr_substs: subst::Substs<'tcx>)
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-> subst::Substs<'tcx>
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{
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let ccx = bcx.ccx();
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let node_substs = node_id_substs(ccx, node, bcx.fcx.param_substs);
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debug!("rcvr_substs={}", rcvr_substs.repr(ccx.tcx()));
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debug!("node_substs={}", node_substs.repr(ccx.tcx()));
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// Break apart the type parameters from the node and type
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// parameters from the receiver.
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let node_method = node_substs.types.split().fns;
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let subst::SeparateVecsPerParamSpace {
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types: rcvr_type,
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selfs: rcvr_self,
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fns: rcvr_method
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} = rcvr_substs.types.clone().split();
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assert!(rcvr_method.is_empty());
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subst::Substs {
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regions: subst::ErasedRegions,
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types: subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method)
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}
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}
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/// Create a method callee where the method is coming from a trait object (e.g., Box<Trait> type).
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/// In this case, we must pull the fn pointer out of the vtable that is packaged up with the
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/// object. Objects are represented as a pair, so we first evaluate the self expression and then
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/// extract the self data and vtable out of the pair.
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fn trans_trait_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
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method_ty: Ty<'tcx>,
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vtable_index: uint,
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self_expr: &ast::Expr,
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arg_cleanup_scope: cleanup::ScopeId)
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-> Callee<'blk, 'tcx> {
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let _icx = push_ctxt("meth::trans_trait_callee");
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let mut bcx = bcx;
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// Translate self_datum and take ownership of the value by
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// converting to an rvalue.
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let self_datum = unpack_datum!(
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bcx, expr::trans(bcx, self_expr));
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|
|
let llval = if bcx.fcx.type_needs_drop(self_datum.ty) {
|
|
let self_datum = unpack_datum!(
|
|
bcx, self_datum.to_rvalue_datum(bcx, "trait_callee"));
|
|
|
|
// Convert to by-ref since `trans_trait_callee_from_llval` wants it
|
|
// that way.
|
|
let self_datum = unpack_datum!(
|
|
bcx, self_datum.to_ref_datum(bcx));
|
|
|
|
// Arrange cleanup in case something should go wrong before the
|
|
// actual call occurs.
|
|
self_datum.add_clean(bcx.fcx, arg_cleanup_scope)
|
|
} else {
|
|
// We don't have to do anything about cleanups for &Trait and &mut Trait.
|
|
assert!(self_datum.kind.is_by_ref());
|
|
self_datum.val
|
|
};
|
|
|
|
trans_trait_callee_from_llval(bcx, method_ty, vtable_index, llval)
|
|
}
|
|
|
|
/// Same as `trans_trait_callee()` above, except that it is given a by-ref pointer to the object
|
|
/// pair.
|
|
pub fn trans_trait_callee_from_llval<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
|
|
callee_ty: Ty<'tcx>,
|
|
vtable_index: uint,
|
|
llpair: ValueRef)
|
|
-> Callee<'blk, 'tcx> {
|
|
let _icx = push_ctxt("meth::trans_trait_callee");
|
|
let ccx = bcx.ccx();
|
|
|
|
// Load the data pointer from the object.
|
|
debug!("trans_trait_callee_from_llval(callee_ty={}, vtable_index={}, llpair={})",
|
|
callee_ty.repr(ccx.tcx()),
|
|
vtable_index,
|
|
bcx.val_to_string(llpair));
|
|
let llboxptr = GEPi(bcx, llpair, &[0, abi::FAT_PTR_ADDR]);
|
|
let llbox = Load(bcx, llboxptr);
|
|
let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
|
|
|
|
// Replace the self type (&Self or Box<Self>) with an opaque pointer.
|
|
let llcallee_ty = match callee_ty.sty {
|
|
ty::ty_bare_fn(_, ref f) if f.abi == Rust || f.abi == RustCall => {
|
|
let fake_sig =
|
|
ty::Binder(ty::FnSig {
|
|
inputs: f.sig.0.inputs[1..].to_vec(),
|
|
output: f.sig.0.output,
|
|
variadic: f.sig.0.variadic,
|
|
});
|
|
type_of_rust_fn(ccx, Some(Type::i8p(ccx)), &fake_sig, f.abi)
|
|
}
|
|
_ => {
|
|
ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
|
|
}
|
|
};
|
|
let llvtable = Load(bcx,
|
|
PointerCast(bcx,
|
|
GEPi(bcx, llpair,
|
|
&[0, abi::FAT_PTR_EXTRA]),
|
|
Type::vtable(ccx).ptr_to().ptr_to()));
|
|
let mptr = Load(bcx, GEPi(bcx, llvtable, &[0, vtable_index + VTABLE_OFFSET]));
|
|
let mptr = PointerCast(bcx, mptr, llcallee_ty.ptr_to());
|
|
|
|
return Callee {
|
|
bcx: bcx,
|
|
data: TraitItem(MethodData {
|
|
llfn: mptr,
|
|
llself: llself,
|
|
})
|
|
};
|
|
}
|
|
|
|
/// Generate a shim function that allows an object type like `SomeTrait` to
|
|
/// implement the type `SomeTrait`. Imagine a trait definition:
|
|
///
|
|
/// trait SomeTrait { fn get(&self) -> int; ... }
|
|
///
|
|
/// And a generic bit of code:
|
|
///
|
|
/// fn foo<T:SomeTrait>(t: &T) {
|
|
/// let x = SomeTrait::get;
|
|
/// x(t)
|
|
/// }
|
|
///
|
|
/// What is the value of `x` when `foo` is invoked with `T=SomeTrait`?
|
|
/// The answer is that it it is a shim function generate by this
|
|
/// routine:
|
|
///
|
|
/// fn shim(t: &SomeTrait) -> int {
|
|
/// // ... call t.get() virtually ...
|
|
/// }
|
|
///
|
|
/// In fact, all virtual calls can be thought of as normal trait calls
|
|
/// that go through this shim function.
|
|
pub fn trans_object_shim<'a, 'tcx>(
|
|
ccx: &'a CrateContext<'a, 'tcx>,
|
|
object_ty: Ty<'tcx>,
|
|
trait_id: ast::DefId,
|
|
method_offset_in_trait: uint)
|
|
-> (ValueRef, Ty<'tcx>)
|
|
{
|
|
let _icx = push_ctxt("trans_object_shim");
|
|
let tcx = ccx.tcx();
|
|
|
|
debug!("trans_object_shim(object_ty={}, trait_id={}, method_offset_in_trait={})",
|
|
object_ty.repr(tcx),
|
|
trait_id.repr(tcx),
|
|
method_offset_in_trait);
|
|
|
|
let object_trait_ref =
|
|
match object_ty.sty {
|
|
ty::ty_trait(ref data) => {
|
|
data.principal_trait_ref_with_self_ty(tcx, object_ty)
|
|
}
|
|
_ => {
|
|
tcx.sess.bug(&format!("trans_object_shim() called on non-object: {}",
|
|
object_ty.repr(tcx)));
|
|
}
|
|
};
|
|
|
|
// Upcast to the trait in question and extract out the substitutions.
|
|
let upcast_trait_ref = traits::upcast(ccx.tcx(), object_trait_ref.clone(), trait_id).unwrap();
|
|
let upcast_trait_ref = ty::erase_late_bound_regions(tcx, &upcast_trait_ref);
|
|
let object_substs = upcast_trait_ref.substs.clone().erase_regions();
|
|
debug!("trans_object_shim: object_substs={}", object_substs.repr(tcx));
|
|
|
|
// Lookup the type of this method as declared in the trait and apply substitutions.
|
|
let method_ty = match ty::trait_item(tcx, trait_id, method_offset_in_trait) {
|
|
ty::MethodTraitItem(method) => method,
|
|
ty::TypeTraitItem(_) => {
|
|
tcx.sess.bug("can't create a method shim for an associated type")
|
|
}
|
|
};
|
|
let fty = monomorphize::apply_param_substs(tcx, &object_substs, &method_ty.fty);
|
|
let fty = tcx.mk_bare_fn(fty);
|
|
let method_ty = opaque_method_ty(tcx, fty);
|
|
debug!("trans_object_shim: fty={} method_ty={}", fty.repr(tcx), method_ty.repr(tcx));
|
|
|
|
//
|
|
let shim_fn_ty = ty::mk_bare_fn(tcx, None, fty);
|
|
let method_bare_fn_ty = ty::mk_bare_fn(tcx, None, method_ty);
|
|
let function_name =
|
|
link::mangle_internal_name_by_type_and_seq(ccx, shim_fn_ty, "object_shim");
|
|
let llfn =
|
|
decl_internal_rust_fn(ccx, shim_fn_ty, &function_name);
|
|
|
|
let sig = ty::erase_late_bound_regions(ccx.tcx(), &fty.sig);
|
|
|
|
let empty_substs = tcx.mk_substs(Substs::trans_empty());
|
|
let (block_arena, fcx): (TypedArena<_>, FunctionContext);
|
|
block_arena = TypedArena::new();
|
|
fcx = new_fn_ctxt(ccx,
|
|
llfn,
|
|
ast::DUMMY_NODE_ID,
|
|
false,
|
|
sig.output,
|
|
empty_substs,
|
|
None,
|
|
&block_arena);
|
|
let mut bcx = init_function(&fcx, false, sig.output);
|
|
|
|
// the first argument (`self`) will be a trait object
|
|
let llobject = get_param(fcx.llfn, fcx.arg_pos(0) as u32);
|
|
|
|
debug!("trans_object_shim: llobject={}",
|
|
bcx.val_to_string(llobject));
|
|
|
|
// the remaining arguments will be, well, whatever they are
|
|
let input_tys =
|
|
match fty.abi {
|
|
RustCall => {
|
|
// unpack the tuple to extract the input type arguments:
|
|
match sig.inputs[1].sty {
|
|
ty::ty_tup(ref tys) => &**tys,
|
|
_ => {
|
|
bcx.sess().bug(
|
|
&format!("rust-call expects a tuple not {}",
|
|
sig.inputs[1].repr(tcx)));
|
|
}
|
|
}
|
|
}
|
|
_ => {
|
|
// skip the self parameter:
|
|
&sig.inputs[1..]
|
|
}
|
|
};
|
|
|
|
let llargs: Vec<_> =
|
|
input_tys.iter()
|
|
.enumerate()
|
|
.map(|(i, _)| {
|
|
let llarg = get_param(fcx.llfn, fcx.arg_pos(i+1) as u32);
|
|
debug!("trans_object_shim: input #{} == {}",
|
|
i, bcx.val_to_string(llarg));
|
|
llarg
|
|
})
|
|
.collect();
|
|
|
|
assert!(!fcx.needs_ret_allocas);
|
|
|
|
let sig =
|
|
ty::erase_late_bound_regions(bcx.tcx(), &fty.sig);
|
|
|
|
let dest =
|
|
fcx.llretslotptr.get().map(
|
|
|_| expr::SaveIn(fcx.get_ret_slot(bcx, sig.output, "ret_slot")));
|
|
|
|
let method_offset_in_vtable =
|
|
traits::get_vtable_index_of_object_method(bcx.tcx(),
|
|
object_trait_ref.clone(),
|
|
trait_id,
|
|
method_offset_in_trait);
|
|
debug!("trans_object_shim: method_offset_in_vtable={}",
|
|
method_offset_in_vtable);
|
|
|
|
bcx = trans_call_inner(bcx,
|
|
DebugLoc::None,
|
|
method_bare_fn_ty,
|
|
|bcx, _| trans_trait_callee_from_llval(bcx,
|
|
method_bare_fn_ty,
|
|
method_offset_in_vtable,
|
|
llobject),
|
|
ArgVals(&llargs),
|
|
dest).bcx;
|
|
|
|
finish_fn(&fcx, bcx, sig.output, DebugLoc::None);
|
|
|
|
(llfn, method_bare_fn_ty)
|
|
}
|
|
|
|
/// Creates a returns a dynamic vtable for the given type and vtable origin.
|
|
/// This is used only for objects.
|
|
///
|
|
/// The `trait_ref` encodes the erased self type. Hence if we are
|
|
/// making an object `Foo<Trait>` from a value of type `Foo<T>`, then
|
|
/// `trait_ref` would map `T:Trait`, but `box_ty` would be
|
|
/// `Foo<T>`. This `box_ty` is primarily used to encode the destructor.
|
|
/// This will hopefully change now that DST is underway.
|
|
pub fn get_vtable<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
|
|
box_ty: Ty<'tcx>,
|
|
trait_ref: ty::PolyTraitRef<'tcx>,
|
|
param_substs: &'tcx subst::Substs<'tcx>)
|
|
-> ValueRef
|
|
{
|
|
let tcx = ccx.tcx();
|
|
let _icx = push_ctxt("meth::get_vtable");
|
|
|
|
debug!("get_vtable(box_ty={}, trait_ref={})",
|
|
box_ty.repr(tcx),
|
|
trait_ref.repr(tcx));
|
|
|
|
// Check the cache.
|
|
let cache_key = (box_ty, trait_ref.clone());
|
|
match ccx.vtables().borrow().get(&cache_key) {
|
|
Some(&val) => { return val }
|
|
None => { }
|
|
}
|
|
|
|
// Not in the cache. Build it.
|
|
let methods = traits::supertraits(tcx, trait_ref.clone()).flat_map(|trait_ref| {
|
|
let vtable = fulfill_obligation(ccx, DUMMY_SP, trait_ref.clone());
|
|
match vtable {
|
|
// Should default trait error here?
|
|
traits::VtableDefaultImpl(_) |
|
|
traits::VtableBuiltin(_) => {
|
|
Vec::new().into_iter()
|
|
}
|
|
traits::VtableImpl(
|
|
traits::VtableImplData {
|
|
impl_def_id: id,
|
|
substs,
|
|
nested: _ }) => {
|
|
emit_vtable_methods(ccx, id, substs, param_substs).into_iter()
|
|
}
|
|
traits::VtableClosure(closure_def_id, substs) => {
|
|
let llfn = trans_fn_ref_with_substs(
|
|
ccx,
|
|
closure_def_id,
|
|
ExprId(0),
|
|
param_substs,
|
|
substs).val;
|
|
|
|
vec![llfn].into_iter()
|
|
}
|
|
traits::VtableFnPointer(bare_fn_ty) => {
|
|
vec![trans_fn_pointer_shim(ccx, bare_fn_ty)].into_iter()
|
|
}
|
|
traits::VtableObject(ref data) => {
|
|
// this would imply that the Self type being erased is
|
|
// an object type; this cannot happen because we
|
|
// cannot cast an unsized type into a trait object
|
|
tcx.sess.bug(
|
|
&format!("cannot get vtable for an object type: {}",
|
|
data.repr(tcx)));
|
|
}
|
|
traits::VtableParam(..) => {
|
|
tcx.sess.bug(
|
|
&format!("resolved vtable for {} to bad vtable {} in trans",
|
|
trait_ref.repr(tcx),
|
|
vtable.repr(tcx)));
|
|
}
|
|
}
|
|
});
|
|
|
|
let size_ty = sizing_type_of(ccx, trait_ref.self_ty());
|
|
let size = machine::llsize_of_alloc(ccx, size_ty);
|
|
let align = align_of(ccx, trait_ref.self_ty());
|
|
|
|
let components: Vec<_> = vec![
|
|
// Generate a destructor for the vtable.
|
|
glue::get_drop_glue(ccx, box_ty),
|
|
C_uint(ccx, size),
|
|
C_uint(ccx, align)
|
|
].into_iter().chain(methods).collect();
|
|
|
|
let vtable = consts::addr_of(ccx, C_struct(ccx, &components, false),
|
|
"vtable", trait_ref.def_id().node);
|
|
|
|
ccx.vtables().borrow_mut().insert(cache_key, vtable);
|
|
vtable
|
|
}
|
|
|
|
fn emit_vtable_methods<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
|
|
impl_id: ast::DefId,
|
|
substs: subst::Substs<'tcx>,
|
|
param_substs: &'tcx subst::Substs<'tcx>)
|
|
-> Vec<ValueRef> {
|
|
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!")
|
|
};
|
|
|
|
ty::populate_implementations_for_trait_if_necessary(tcx, trt_id);
|
|
|
|
let trait_item_def_ids = ty::trait_item_def_ids(tcx, trt_id);
|
|
trait_item_def_ids.iter().flat_map(|method_def_id| {
|
|
let method_def_id = method_def_id.def_id();
|
|
let name = ty::impl_or_trait_item(tcx, method_def_id).name();
|
|
// The substitutions we have are on the impl, so we grab
|
|
// the method type from the impl to substitute into.
|
|
let m_id = method_with_name(ccx, impl_id, name);
|
|
let ti = ty::impl_or_trait_item(tcx, m_id);
|
|
match ti {
|
|
ty::MethodTraitItem(m) => {
|
|
debug!("(making impl vtable) emitting method {} at subst {}",
|
|
m.repr(tcx),
|
|
substs.repr(tcx));
|
|
if m.generics.has_type_params(subst::FnSpace) ||
|
|
ty::type_has_self(ty::mk_bare_fn(tcx, None, tcx.mk_bare_fn(m.fty.clone())))
|
|
{
|
|
debug!("(making impl vtable) method has self or type \
|
|
params: {}",
|
|
token::get_name(name));
|
|
Some(C_null(Type::nil(ccx).ptr_to())).into_iter()
|
|
} else {
|
|
let fn_ref = trans_fn_ref_with_substs(
|
|
ccx,
|
|
m_id,
|
|
ExprId(0),
|
|
param_substs,
|
|
substs.clone()).val;
|
|
|
|
Some(fn_ref).into_iter()
|
|
}
|
|
}
|
|
ty::TypeTraitItem(_) => {
|
|
None.into_iter()
|
|
}
|
|
}
|
|
}).collect()
|
|
}
|
|
|
|
/// Generates the code to convert from a pointer (`Box<T>`, `&T`, etc) into an object
|
|
/// (`Box<Trait>`, `&Trait`, etc). This means creating a pair where the first word is the vtable
|
|
/// and the second word is the pointer.
|
|
pub fn trans_trait_cast<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
|
|
datum: Datum<'tcx, Expr>,
|
|
id: ast::NodeId,
|
|
trait_ref: ty::PolyTraitRef<'tcx>,
|
|
dest: expr::Dest)
|
|
-> Block<'blk, 'tcx> {
|
|
let mut bcx = bcx;
|
|
let _icx = push_ctxt("meth::trans_trait_cast");
|
|
|
|
let lldest = match dest {
|
|
Ignore => {
|
|
return datum.clean(bcx, "trait_trait_cast", id);
|
|
}
|
|
SaveIn(dest) => dest
|
|
};
|
|
|
|
debug!("trans_trait_cast: trait_ref={}",
|
|
trait_ref.repr(bcx.tcx()));
|
|
|
|
let datum_ty = datum.ty;
|
|
let llbox_ty = type_of(bcx.ccx(), datum_ty);
|
|
|
|
// Store the pointer into the first half of pair.
|
|
let llboxdest = GEPi(bcx, lldest, &[0, abi::FAT_PTR_ADDR]);
|
|
let llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
|
|
bcx = datum.store_to(bcx, llboxdest);
|
|
|
|
// Store the vtable into the second half of pair.
|
|
let vtable = get_vtable(bcx.ccx(), datum_ty, trait_ref, bcx.fcx.param_substs);
|
|
let llvtabledest = GEPi(bcx, lldest, &[0, abi::FAT_PTR_EXTRA]);
|
|
let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
|
|
Store(bcx, vtable, llvtabledest);
|
|
|
|
bcx
|
|
}
|
|
|
|
/// Replace the self type (&Self or Box<Self>) with an opaque pointer.
|
|
pub fn opaque_method_ty<'tcx>(tcx: &ty::ctxt<'tcx>, method_ty: &ty::BareFnTy<'tcx>)
|
|
-> &'tcx ty::BareFnTy<'tcx> {
|
|
let mut inputs = method_ty.sig.0.inputs.clone();
|
|
inputs[0] = ty::mk_mut_ptr(tcx, ty::mk_mach_int(tcx, ast::TyI8));
|
|
|
|
tcx.mk_bare_fn(ty::BareFnTy {
|
|
unsafety: method_ty.unsafety,
|
|
abi: method_ty.abi,
|
|
sig: ty::Binder(ty::FnSig {
|
|
inputs: inputs,
|
|
output: method_ty.sig.0.output,
|
|
variadic: method_ty.sig.0.variadic,
|
|
}),
|
|
})
|
|
}
|