8d27232141
This patch primarily does two things: (1) it prevents lifetimes from
leaking out of unboxed closures; (2) it allows unboxed closure type
notation, call notation, and construction notation to construct closures
matching any of the three traits.
This breaks code that looked like:
let mut f;
{
let x = &5i;
f = |&mut:| *x + 10;
}
Change this code to avoid having a reference escape. For example:
{
let x = &5i;
let mut f; // <-- move here to avoid dangling reference
f = |&mut:| *x + 10;
}
I believe this is enough to consider unboxed closures essentially
implemented. Further issues (for example, higher-rank lifetimes) should
be filed as followups.
Closes #14449.
[breaking-change]
637 lines
24 KiB
Rust
637 lines
24 KiB
Rust
// 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 <LICENSE-APACHE or
|
|
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
|
|
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
|
|
// option. This file may not be copied, modified, or distributed
|
|
// except according to those terms.
|
|
|
|
|
|
use back::abi;
|
|
use llvm;
|
|
use llvm::ValueRef;
|
|
use metadata::csearch;
|
|
use middle::subst::VecPerParamSpace;
|
|
use middle::subst;
|
|
use middle::trans::base::*;
|
|
use middle::trans::build::*;
|
|
use middle::trans::callee::*;
|
|
use middle::trans::callee;
|
|
use middle::trans::cleanup;
|
|
use middle::trans::common::*;
|
|
use middle::trans::datum::*;
|
|
use middle::trans::expr::{SaveIn, Ignore};
|
|
use middle::trans::expr;
|
|
use middle::trans::glue;
|
|
use middle::trans::monomorphize;
|
|
use middle::trans::type_::Type;
|
|
use middle::trans::type_of::*;
|
|
use middle::ty;
|
|
use middle::typeck;
|
|
use middle::typeck::MethodCall;
|
|
use util::common::indenter;
|
|
use util::ppaux::Repr;
|
|
|
|
use std::c_str::ToCStr;
|
|
use std::gc::Gc;
|
|
use syntax::abi::{Rust, RustCall};
|
|
use syntax::parse::token;
|
|
use syntax::{ast, ast_map, visit};
|
|
use syntax::ast_util::PostExpansionMethod;
|
|
|
|
/**
|
|
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: &CrateContext,
|
|
name: ast::Ident,
|
|
methods: &[Gc<ast::Method>],
|
|
generics: &ast::Generics,
|
|
id: ast::NodeId) {
|
|
let _icx = push_ctxt("meth::trans_impl");
|
|
let tcx = ccx.tcx();
|
|
|
|
debug!("trans_impl(name={}, id={:?})", name.repr(tcx), id);
|
|
|
|
// Both here and below with generic methods, be sure to recurse and look for
|
|
// items that we need to translate.
|
|
if !generics.ty_params.is_empty() {
|
|
let mut v = TransItemVisitor{ ccx: ccx };
|
|
for method in methods.iter() {
|
|
visit::walk_method_helper(&mut v, &**method, ());
|
|
}
|
|
return;
|
|
}
|
|
for method in methods.iter() {
|
|
if method.pe_generics().ty_params.len() == 0u {
|
|
let llfn = get_item_val(ccx, method.id);
|
|
trans_fn(ccx,
|
|
&*method.pe_fn_decl(),
|
|
&*method.pe_body(),
|
|
llfn,
|
|
¶m_substs::empty(),
|
|
method.id,
|
|
[]);
|
|
}
|
|
let mut v = TransItemVisitor{ ccx: ccx };
|
|
visit::walk_method_helper(&mut v, &**method, ());
|
|
}
|
|
}
|
|
|
|
pub fn trans_method_callee<'a>(
|
|
bcx: &'a Block<'a>,
|
|
method_call: MethodCall,
|
|
self_expr: Option<&ast::Expr>,
|
|
arg_cleanup_scope: cleanup::ScopeId)
|
|
-> Callee<'a> {
|
|
let _icx = push_ctxt("meth::trans_method_callee");
|
|
|
|
let (origin, method_ty) = match bcx.tcx().method_map
|
|
.borrow().find(&method_call) {
|
|
Some(method) => {
|
|
debug!("trans_method_callee({:?}, method={})",
|
|
method_call, method.repr(bcx.tcx()));
|
|
(method.origin, method.ty)
|
|
}
|
|
None => {
|
|
bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
|
|
"method call expr wasn't in method map")
|
|
}
|
|
};
|
|
|
|
match origin {
|
|
typeck::MethodStatic(did) |
|
|
typeck::MethodStaticUnboxedClosure(did) => {
|
|
Callee {
|
|
bcx: bcx,
|
|
data: Fn(callee::trans_fn_ref(bcx,
|
|
did,
|
|
MethodCall(method_call))),
|
|
}
|
|
}
|
|
typeck::MethodParam(typeck::MethodParam {
|
|
trait_id: trait_id,
|
|
method_num: off,
|
|
param_num: p,
|
|
bound_num: b
|
|
}) => {
|
|
ty::populate_implementations_for_trait_if_necessary(
|
|
bcx.tcx(),
|
|
trait_id);
|
|
|
|
let vtbl = find_vtable(bcx.tcx(), bcx.fcx.param_substs, p, b);
|
|
trans_monomorphized_callee(bcx, method_call,
|
|
trait_id, off, vtbl)
|
|
}
|
|
|
|
typeck::MethodObject(ref mt) => {
|
|
let self_expr = match self_expr {
|
|
Some(self_expr) => self_expr,
|
|
None => {
|
|
bcx.sess().span_bug(bcx.tcx().map.span(method_call.expr_id),
|
|
"self expr wasn't provided for trait object \
|
|
callee (trying to call overloaded op?)")
|
|
}
|
|
};
|
|
trans_trait_callee(bcx,
|
|
monomorphize_type(bcx, method_ty),
|
|
mt.real_index,
|
|
self_expr,
|
|
arg_cleanup_scope)
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn trans_static_method_callee(bcx: &Block,
|
|
method_id: ast::DefId,
|
|
trait_id: ast::DefId,
|
|
expr_id: ast::NodeId)
|
|
-> ValueRef {
|
|
let _icx = push_ctxt("meth::trans_static_method_callee");
|
|
let ccx = bcx.ccx();
|
|
|
|
debug!("trans_static_method_callee(method_id={:?}, trait_id={}, \
|
|
expr_id={:?})",
|
|
method_id,
|
|
ty::item_path_str(bcx.tcx(), trait_id),
|
|
expr_id);
|
|
let _indenter = indenter();
|
|
|
|
ty::populate_implementations_for_trait_if_necessary(bcx.tcx(), trait_id);
|
|
|
|
let mname = if method_id.krate == ast::LOCAL_CRATE {
|
|
match bcx.tcx().map.get(method_id.node) {
|
|
ast_map::NodeTraitMethod(method) => {
|
|
let ident = match *method {
|
|
ast::Required(ref m) => m.ident,
|
|
ast::Provided(ref m) => m.pe_ident()
|
|
};
|
|
ident.name
|
|
}
|
|
_ => fail!("callee is not a trait method")
|
|
}
|
|
} else {
|
|
csearch::get_item_path(bcx.tcx(), method_id).last().unwrap().name()
|
|
};
|
|
debug!("trans_static_method_callee: method_id={:?}, expr_id={:?}, \
|
|
name={}", method_id, expr_id, token::get_name(mname));
|
|
|
|
let vtable_key = MethodCall::expr(expr_id);
|
|
let vtbls = resolve_vtables_in_fn_ctxt(
|
|
bcx.fcx,
|
|
ccx.tcx.vtable_map.borrow().get(&vtable_key));
|
|
|
|
match *vtbls.get_self().unwrap().get(0) {
|
|
typeck::vtable_static(impl_did, ref rcvr_substs, ref rcvr_origins) => {
|
|
assert!(rcvr_substs.types.all(|t| !ty::type_needs_infer(*t)));
|
|
|
|
let mth_id = method_with_name(ccx, impl_did, mname);
|
|
let (callee_substs, callee_origins) =
|
|
combine_impl_and_methods_tps(
|
|
bcx, ExprId(expr_id),
|
|
(*rcvr_substs).clone(), (*rcvr_origins).clone());
|
|
|
|
let llfn = trans_fn_ref_with_vtables(bcx, mth_id, ExprId(expr_id),
|
|
callee_substs,
|
|
callee_origins);
|
|
|
|
let callee_ty = node_id_type(bcx, expr_id);
|
|
let llty = type_of_fn_from_ty(ccx, callee_ty).ptr_to();
|
|
PointerCast(bcx, llfn, llty)
|
|
}
|
|
typeck::vtable_unboxed_closure(_) => {
|
|
bcx.tcx().sess.bug("can't call a closure vtable in a static way");
|
|
}
|
|
_ => {
|
|
fail!("vtable_param left in monomorphized \
|
|
function's vtable substs");
|
|
}
|
|
}
|
|
}
|
|
|
|
fn method_with_name(ccx: &CrateContext,
|
|
impl_id: ast::DefId,
|
|
name: ast::Name) -> ast::DefId {
|
|
match ccx.impl_method_cache.borrow().find_copy(&(impl_id, name)) {
|
|
Some(m) => return m,
|
|
None => {}
|
|
}
|
|
|
|
let methods = ccx.tcx.impl_methods.borrow();
|
|
let methods = methods.find(&impl_id)
|
|
.expect("could not find impl while translating");
|
|
let meth_did = methods.iter().find(|&did| ty::method(&ccx.tcx, *did).ident.name == name)
|
|
.expect("could not find method while translating");
|
|
|
|
ccx.impl_method_cache.borrow_mut().insert((impl_id, name), *meth_did);
|
|
*meth_did
|
|
}
|
|
|
|
fn trans_monomorphized_callee<'a>(
|
|
bcx: &'a Block<'a>,
|
|
method_call: MethodCall,
|
|
trait_id: ast::DefId,
|
|
n_method: uint,
|
|
vtbl: typeck::vtable_origin)
|
|
-> Callee<'a> {
|
|
let _icx = push_ctxt("meth::trans_monomorphized_callee");
|
|
match vtbl {
|
|
typeck::vtable_static(impl_did, 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(bcx.ccx(), impl_did, mname.name);
|
|
|
|
// 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, MethodCall(method_call), rcvr_substs, rcvr_origins);
|
|
|
|
// translate the function
|
|
let llfn = trans_fn_ref_with_vtables(bcx,
|
|
mth_id,
|
|
MethodCall(method_call),
|
|
callee_substs,
|
|
callee_origins);
|
|
|
|
Callee { bcx: bcx, data: Fn(llfn) }
|
|
}
|
|
typeck::vtable_unboxed_closure(closure_def_id) => {
|
|
// The static region and type parameters are lies, but we're in
|
|
// trans so it doesn't matter.
|
|
//
|
|
// FIXME(pcwalton): Is this true in the case of type parameters?
|
|
let callee_substs = get_callee_substitutions_for_unboxed_closure(
|
|
bcx,
|
|
closure_def_id);
|
|
|
|
let llfn = trans_fn_ref_with_vtables(bcx,
|
|
closure_def_id,
|
|
MethodCall(method_call),
|
|
callee_substs,
|
|
VecPerParamSpace::empty());
|
|
|
|
Callee {
|
|
bcx: bcx,
|
|
data: Fn(llfn),
|
|
}
|
|
}
|
|
typeck::vtable_param(..) => {
|
|
bcx.tcx().sess.bug(
|
|
"vtable_param left in monomorphized function's vtable substs");
|
|
}
|
|
typeck::vtable_error => {
|
|
bcx.tcx().sess.bug(
|
|
"vtable_error left in monomorphized function's vtable substs");
|
|
}
|
|
}
|
|
}
|
|
|
|
fn combine_impl_and_methods_tps(bcx: &Block,
|
|
node: ExprOrMethodCall,
|
|
rcvr_substs: subst::Substs,
|
|
rcvr_origins: typeck::vtable_res)
|
|
-> (subst::Substs, 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<B,C,D>` 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<X>`. 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 vtable_key = match node {
|
|
ExprId(id) => MethodCall::expr(id),
|
|
MethodCall(method_call) => method_call
|
|
};
|
|
let node_substs = node_id_substs(bcx, node);
|
|
let node_vtables = node_vtables(bcx, vtable_key);
|
|
|
|
debug!("rcvr_substs={:?}", rcvr_substs.repr(ccx.tcx()));
|
|
debug!("node_substs={:?}", node_substs.repr(ccx.tcx()));
|
|
|
|
// Break apart the type parameters from the node and type
|
|
// parameters from the receiver.
|
|
let (_, _, node_method) = node_substs.types.split();
|
|
let (rcvr_type, rcvr_self, rcvr_method) = rcvr_substs.types.clone().split();
|
|
assert!(rcvr_method.is_empty());
|
|
let ty_substs = subst::Substs {
|
|
regions: subst::ErasedRegions,
|
|
types: subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method)
|
|
};
|
|
|
|
// Now do the same work for the vtables.
|
|
let (rcvr_type, rcvr_self, rcvr_method) = rcvr_origins.split();
|
|
let (_, _, node_method) = node_vtables.split();
|
|
assert!(rcvr_method.is_empty());
|
|
let vtables = subst::VecPerParamSpace::new(rcvr_type, rcvr_self, node_method);
|
|
|
|
(ty_substs, vtables)
|
|
}
|
|
|
|
fn trans_trait_callee<'a>(bcx: &'a Block<'a>,
|
|
method_ty: ty::t,
|
|
n_method: uint,
|
|
self_expr: &ast::Expr,
|
|
arg_cleanup_scope: cleanup::ScopeId)
|
|
-> Callee<'a> {
|
|
/*!
|
|
* Create a method callee where the method is coming from a trait
|
|
* object (e.g., Box<Trait> type). In this case, we must pull the fn
|
|
* pointer out of the vtable that is packaged up with the object.
|
|
* Objects are represented as a pair, so we first evaluate the self
|
|
* expression and then extract the self data and vtable out of the
|
|
* pair.
|
|
*/
|
|
|
|
let _icx = push_ctxt("meth::trans_trait_callee");
|
|
let mut bcx = bcx;
|
|
|
|
// Translate self_datum and take ownership of the value by
|
|
// converting to an rvalue.
|
|
let self_datum = unpack_datum!(
|
|
bcx, expr::trans(bcx, self_expr));
|
|
|
|
let llval = if ty::type_needs_drop(bcx.tcx(), 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, n_method, llval)
|
|
}
|
|
|
|
pub fn trans_trait_callee_from_llval<'a>(bcx: &'a Block<'a>,
|
|
callee_ty: ty::t,
|
|
n_method: uint,
|
|
llpair: ValueRef)
|
|
-> Callee<'a> {
|
|
/*!
|
|
* Same as `trans_trait_callee()` above, except that it is given
|
|
* a by-ref pointer to the object pair.
|
|
*/
|
|
|
|
let _icx = push_ctxt("meth::trans_trait_callee");
|
|
let ccx = bcx.ccx();
|
|
|
|
// Load the data pointer from the object.
|
|
debug!("(translating trait callee) loading second index from pair");
|
|
let llboxptr = GEPi(bcx, llpair, [0u, abi::trt_field_box]);
|
|
let llbox = Load(bcx, llboxptr);
|
|
let llself = PointerCast(bcx, llbox, Type::i8p(ccx));
|
|
|
|
// Load the function from the vtable and cast it to the expected type.
|
|
debug!("(translating trait callee) loading method");
|
|
// Replace the self type (&Self or Box<Self>) with an opaque pointer.
|
|
let llcallee_ty = match ty::get(callee_ty).sty {
|
|
ty::ty_bare_fn(ref f) if f.abi == Rust || f.abi == RustCall => {
|
|
type_of_rust_fn(ccx,
|
|
Some(Type::i8p(ccx)),
|
|
f.sig.inputs.slice_from(1),
|
|
f.sig.output,
|
|
f.abi)
|
|
}
|
|
_ => {
|
|
ccx.sess().bug("meth::trans_trait_callee given non-bare-rust-fn");
|
|
}
|
|
};
|
|
let llvtable = Load(bcx,
|
|
PointerCast(bcx,
|
|
GEPi(bcx, llpair,
|
|
[0u, abi::trt_field_vtable]),
|
|
Type::vtable(ccx).ptr_to().ptr_to()));
|
|
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: TraitMethod(MethodData {
|
|
llfn: mptr,
|
|
llself: llself,
|
|
})
|
|
};
|
|
}
|
|
|
|
/// Creates the self type and (fake) callee substitutions for an unboxed
|
|
/// closure with the given def ID. The static region and type parameters are
|
|
/// lies, but we're in trans so it doesn't matter.
|
|
fn get_callee_substitutions_for_unboxed_closure(bcx: &Block,
|
|
def_id: ast::DefId)
|
|
-> subst::Substs {
|
|
let self_ty = ty::mk_unboxed_closure(bcx.tcx(), def_id, ty::ReStatic);
|
|
subst::Substs::erased(
|
|
VecPerParamSpace::new(Vec::new(),
|
|
vec![
|
|
ty::mk_rptr(bcx.tcx(),
|
|
ty::ReStatic,
|
|
ty::mt {
|
|
ty: self_ty,
|
|
mutbl: ast::MutMutable,
|
|
})
|
|
],
|
|
Vec::new()))
|
|
}
|
|
|
|
/// Creates a returns a dynamic vtable for the given type and vtable origin.
|
|
/// This is used only for objects.
|
|
fn get_vtable(bcx: &Block,
|
|
self_ty: ty::t,
|
|
origins: typeck::vtable_param_res)
|
|
-> ValueRef
|
|
{
|
|
debug!("get_vtable(self_ty={}, origins={})",
|
|
self_ty.repr(bcx.tcx()),
|
|
origins.repr(bcx.tcx()));
|
|
|
|
let ccx = bcx.ccx();
|
|
let _icx = push_ctxt("meth::get_vtable");
|
|
|
|
// Check the cache.
|
|
let hash_id = (self_ty, monomorphize::make_vtable_id(ccx, origins.get(0)));
|
|
match ccx.vtables.borrow().find(&hash_id) {
|
|
Some(&val) => { return val }
|
|
None => { }
|
|
}
|
|
|
|
// Not in the cache. Actually build it.
|
|
let methods = origins.move_iter().flat_map(|origin| {
|
|
match origin {
|
|
typeck::vtable_static(id, substs, sub_vtables) => {
|
|
emit_vtable_methods(bcx, id, substs, sub_vtables).move_iter()
|
|
}
|
|
typeck::vtable_unboxed_closure(closure_def_id) => {
|
|
let callee_substs =
|
|
get_callee_substitutions_for_unboxed_closure(
|
|
bcx,
|
|
closure_def_id);
|
|
|
|
let llfn = trans_fn_ref_with_vtables(
|
|
bcx,
|
|
closure_def_id,
|
|
ExprId(0),
|
|
callee_substs,
|
|
VecPerParamSpace::empty());
|
|
|
|
(vec!(llfn)).move_iter()
|
|
}
|
|
_ => ccx.sess().bug("get_vtable: expected a static origin"),
|
|
}
|
|
});
|
|
|
|
// Generate a destructor for the vtable.
|
|
let drop_glue = glue::get_drop_glue(ccx, self_ty);
|
|
let vtable = make_vtable(ccx, drop_glue, methods);
|
|
|
|
ccx.vtables.borrow_mut().insert(hash_id, vtable);
|
|
vtable
|
|
}
|
|
|
|
/// Helper function to declare and initialize the vtable.
|
|
pub fn make_vtable<I: Iterator<ValueRef>>(ccx: &CrateContext,
|
|
drop_glue: ValueRef,
|
|
ptrs: I)
|
|
-> ValueRef {
|
|
let _icx = push_ctxt("meth::make_vtable");
|
|
|
|
let components: Vec<_> = Some(drop_glue).move_iter().chain(ptrs).collect();
|
|
|
|
unsafe {
|
|
let tbl = C_struct(ccx, components.as_slice(), false);
|
|
let sym = token::gensym("vtable");
|
|
let vt_gvar = format!("vtable{}", sym.uint()).with_c_str(|buf| {
|
|
llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl).to_ref(), buf)
|
|
});
|
|
llvm::LLVMSetInitializer(vt_gvar, tbl);
|
|
llvm::LLVMSetGlobalConstant(vt_gvar, llvm::True);
|
|
llvm::SetLinkage(vt_gvar, llvm::InternalLinkage);
|
|
vt_gvar
|
|
}
|
|
}
|
|
|
|
fn emit_vtable_methods(bcx: &Block,
|
|
impl_id: ast::DefId,
|
|
substs: subst::Substs,
|
|
vtables: typeck::vtable_res)
|
|
-> Vec<ValueRef> {
|
|
let ccx = bcx.ccx();
|
|
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(bcx.tcx(), trt_id);
|
|
|
|
let trait_method_def_ids = ty::trait_method_def_ids(tcx, trt_id);
|
|
trait_method_def_ids.iter().map(|method_def_id| {
|
|
let ident = ty::method(tcx, *method_def_id).ident;
|
|
// 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, ident.name);
|
|
let m = ty::method(tcx, m_id);
|
|
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, m.fty.clone())) {
|
|
debug!("(making impl vtable) method has self or type params: {}",
|
|
token::get_ident(ident));
|
|
C_null(Type::nil(ccx).ptr_to())
|
|
} else {
|
|
let mut fn_ref = trans_fn_ref_with_vtables(bcx,
|
|
m_id,
|
|
ExprId(0),
|
|
substs.clone(),
|
|
vtables.clone());
|
|
if m.explicit_self == ty::ByValueExplicitSelfCategory {
|
|
fn_ref = trans_unboxing_shim(bcx,
|
|
fn_ref,
|
|
&*m,
|
|
m_id,
|
|
substs.clone());
|
|
}
|
|
fn_ref
|
|
}
|
|
}).collect()
|
|
}
|
|
|
|
pub fn trans_trait_cast<'a>(bcx: &'a Block<'a>,
|
|
datum: Datum<Expr>,
|
|
id: ast::NodeId,
|
|
dest: expr::Dest)
|
|
-> &'a Block<'a> {
|
|
/*!
|
|
* 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.
|
|
*/
|
|
|
|
let mut bcx = bcx;
|
|
let _icx = push_ctxt("meth::trans_cast");
|
|
|
|
let lldest = match dest {
|
|
Ignore => {
|
|
return datum.clean(bcx, "trait_cast", id);
|
|
}
|
|
SaveIn(dest) => dest
|
|
};
|
|
|
|
let ccx = bcx.ccx();
|
|
let v_ty = datum.ty;
|
|
let llbox_ty = type_of(bcx.ccx(), datum.ty);
|
|
|
|
// Store the pointer into the first half of pair.
|
|
let mut llboxdest = GEPi(bcx, lldest, [0u, abi::trt_field_box]);
|
|
llboxdest = PointerCast(bcx, llboxdest, llbox_ty.ptr_to());
|
|
bcx = datum.store_to(bcx, llboxdest);
|
|
|
|
// Store the vtable into the second half of pair.
|
|
let origins = {
|
|
let vtable_map = ccx.tcx.vtable_map.borrow();
|
|
// This trait cast might be because of implicit coercion
|
|
let method_call = match ccx.tcx.adjustments.borrow().find(&id) {
|
|
Some(&ty::AutoObject(..)) => MethodCall::autoobject(id),
|
|
_ => MethodCall::expr(id)
|
|
};
|
|
let vres = vtable_map.get(&method_call).get_self().unwrap();
|
|
resolve_param_vtables_under_param_substs(ccx.tcx(), bcx.fcx.param_substs, vres)
|
|
};
|
|
let vtable = get_vtable(bcx, v_ty, origins);
|
|
let llvtabledest = GEPi(bcx, lldest, [0u, abi::trt_field_vtable]);
|
|
let llvtabledest = PointerCast(bcx, llvtabledest, val_ty(vtable).ptr_to());
|
|
Store(bcx, vtable, llvtabledest);
|
|
|
|
bcx
|
|
}
|