rust/src/rustc/middle/trans/impl.rs

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import libc::c_uint;
import base::*;
import common::*;
import type_of::*;
import build::*;
import driver::session::session;
import syntax::{ast, ast_map};
import ast_map::{path, path_mod, path_name, node_id_to_str};
import driver::session::expect;
import syntax::ast_util::local_def;
import metadata::csearch;
import back::{link, abi};
import lib::llvm::llvm;
import lib::llvm::{ValueRef, TypeRef};
import lib::llvm::llvm::LLVMGetParam;
import std::map::hashmap;
import util::ppaux::{ty_to_str, tys_to_str};
import syntax::print::pprust::expr_to_str;
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/**
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()`.
*/
fn trans_impl(ccx: @crate_ctxt, path: path, name: ast::ident,
methods: ~[@ast::method], tps: ~[ast::ty_param]) {
let _icx = ccx.insn_ctxt("impl::trans_impl");
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if tps.len() > 0u { return; }
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let sub_path = vec::append_one(path, path_name(name));
for vec::each(methods) |method| {
if method.tps.len() == 0u {
let llfn = get_item_val(ccx, method.id);
let path = vec::append_one(sub_path, path_name(method.ident));
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trans_method(ccx, path, method, None, llfn);
}
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}
}
/**
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
*/
fn trans_method(ccx: @crate_ctxt,
path: path,
method: &ast::method,
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param_substs: Option<param_substs>,
llfn: ValueRef) {
// figure out how self is being passed
let self_arg = match method.self_ty.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 {
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None => self_ty,
Some({tys: ref tys, _}) => ty::subst_tps(ccx.tcx, *tys, self_ty)
};
match method.self_ty.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);
}
fn trans_self_arg(bcx: block, base: @ast::expr,
mentry: typeck::method_map_entry) -> result {
let _icx = bcx.insn_ctxt("impl::trans_self_arg");
let basety = expr_ty(bcx, base);
let mode = ast::expl(mentry.self_mode);
let mut temp_cleanups = ~[];
let result = trans_arg_expr(bcx, {mode: mode, ty: basety},
T_ptr(type_of::type_of(bcx.ccx(), basety)),
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base, temp_cleanups, None, mentry.derefs);
// by-ref self argument should not require cleanup in the case of
// other arguments failing:
//assert temp_cleanups == ~[];
//do vec::iter(temp_cleanups) |c| {
// revoke_clean(bcx, c)
//}
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return result;
}
fn trans_method_callee(bcx: block, callee_id: ast::node_id,
self: @ast::expr, mentry: typeck::method_map_entry)
-> lval_maybe_callee {
let _icx = bcx.insn_ctxt("impl::trans_method_callee");
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match mentry.origin {
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typeck::method_static(did) => {
let {bcx, val} = trans_self_arg(bcx, self, mentry);
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{env: self_env(val, node_id_type(bcx, self.id), None,
mentry.self_mode)
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with lval_static_fn(bcx, did, callee_id)}
}
typeck::method_param({trait_id:trait_id, method_num:off,
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param_num:p, bound_num:b}) => {
match bcx.fcx.param_substs {
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Some(substs) => {
let vtbl = find_vtable_in_fn_ctxt(substs, p, b);
trans_monomorphized_callee(bcx, callee_id, self, mentry,
trait_id, off, vtbl)
}
// how to get rid of this?
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None => fail ~"trans_method_callee: missing param_substs"
}
}
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typeck::method_trait(_, off) => {
let {bcx, val} = trans_temp_expr(bcx, self);
let fty = node_id_type(bcx, callee_id);
let self_ty = node_id_type(bcx, self.id);
let {bcx, val, _} = autoderef(bcx, self.id, val, self_ty,
uint::max_value);
trans_trait_callee(bcx, val, fty, off)
}
}
}
fn trans_static_method_callee(bcx: block, method_id: ast::def_id,
callee_id: ast::node_id) -> lval_maybe_callee {
let _icx = bcx.insn_ctxt("impl::trans_static_method_callee");
let ccx = bcx.ccx();
let mname = if method_id.crate == ast::local_crate {
match bcx.tcx().items.get(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=%?, \
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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(callee_id));
match vtbls[0] { // is index 0 always the one we want?
typeck::vtable_static(impl_did, impl_substs, sub_origins) => {
let mth_id = method_with_name(bcx.ccx(), impl_did, mname);
let n_m_tps = method_ty_param_count(ccx, mth_id, impl_did);
let node_substs = node_id_type_params(bcx, callee_id);
let ty_substs
= vec::append(impl_substs,
vec::tailn(node_substs,
node_substs.len() - n_m_tps));
let lval = lval_static_fn_inner(bcx, mth_id, callee_id, ty_substs,
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Some(sub_origins));
{env: null_env,
val: PointerCast(bcx, lval.val, T_ptr(type_of_fn_from_ty(
ccx, node_id_type(bcx, callee_id))))
with lval}
}
_ => {
fail ~"vtable_param left in monomorphized function's vtable substs";
}
}
}
fn method_from_methods(ms: ~[@ast::method], name: ast::ident)
-> ast::def_id {
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local_def(option::get(vec::find(ms, |m| m.ident == name)).id)
}
fn method_with_name(ccx: @crate_ctxt, impl_id: ast::def_id,
name: ast::ident) -> ast::def_id {
if impl_id.crate == ast::local_crate {
match ccx.tcx.items.get(impl_id.node) {
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ast_map::node_item(@{node: ast::item_impl(_, _, _, ms), _}, _) => {
method_from_methods(ms, name)
}
ast_map::node_item(@{node:
ast::item_class(struct_def, _), _}, _) => {
method_from_methods(struct_def.methods, name)
}
_ => fail ~"method_with_name"
}
} else {
csearch::get_impl_method(ccx.sess.cstore, impl_id, name)
}
}
fn method_ty_param_count(ccx: @crate_ctxt, m_id: ast::def_id,
i_id: ast::def_id) -> uint {
if m_id.crate == ast::local_crate {
match ccx.tcx.items.get(m_id.node) {
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ast_map::node_method(m, _, _) => vec::len(m.tps),
_ => fail ~"method_ty_param_count"
}
} else {
csearch::get_type_param_count(ccx.sess.cstore, m_id) -
csearch::get_type_param_count(ccx.sess.cstore, i_id)
}
}
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)
-> lval_maybe_callee {
let _icx = bcx.insn_ctxt("impl::trans_monomorphized_callee");
match vtbl {
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typeck::vtable_static(impl_did, impl_substs, sub_origins) => {
let ccx = bcx.ccx();
let mname = ty::trait_methods(ccx.tcx, trait_id)[n_method].ident;
let mth_id = method_with_name(bcx.ccx(), impl_did, mname);
let n_m_tps = method_ty_param_count(ccx, mth_id, impl_did);
let node_substs = node_id_type_params(bcx, callee_id);
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let ty_substs
= vec::append(impl_substs,
vec::tailn(node_substs,
node_substs.len() - n_m_tps));
let {bcx, val} = trans_self_arg(bcx, base, mentry);
let lval = lval_static_fn_inner(bcx, mth_id, callee_id, ty_substs,
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Some(sub_origins));
{env: self_env(val, node_id_type(bcx, base.id),
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None, mentry.self_mode),
val: PointerCast(bcx, lval.val, T_ptr(type_of_fn_from_ty(
ccx, node_id_type(bcx, callee_id))))
with lval}
}
typeck::vtable_trait(trait_id, tps) => {
let {bcx, val} = trans_temp_expr(bcx, base);
let fty = node_id_type(bcx, callee_id);
trans_trait_callee(bcx, val, fty, n_method)
}
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typeck::vtable_param(n_param, n_bound) => {
fail ~"vtable_param left in monomorphized function's vtable substs";
}
}
}
// Method callee where the vtable comes from a boxed trait
fn trans_trait_callee(bcx: block, val: ValueRef,
callee_ty: ty::t, n_method: uint)
-> lval_maybe_callee {
let _icx = bcx.insn_ctxt("impl::trans_trait_callee");
let ccx = bcx.ccx();
let vtable = Load(bcx, PointerCast(bcx, GEPi(bcx, val, ~[0u, 0u]),
T_ptr(T_ptr(T_vtable()))));
let llbox = Load(bcx, GEPi(bcx, val, ~[0u, 1u]));
// FIXME[impl] I doubt this is alignment-safe (#2534)
let self = GEPi(bcx, llbox, ~[0u, abi::box_field_body]);
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let env = self_env(self, ty::mk_opaque_box(bcx.tcx()), Some(llbox),
// XXX: is this bogosity?
ast::by_ref);
let llfty = type_of::type_of_fn_from_ty(ccx, callee_ty);
let vtable = PointerCast(bcx, vtable,
T_ptr(T_array(T_ptr(llfty), n_method + 1u)));
let mptr = Load(bcx, GEPi(bcx, vtable, ~[0u, n_method]));
{bcx: bcx, val: mptr, kind: lv_owned, env: env}
}
fn find_vtable_in_fn_ctxt(ps: param_substs, n_param: uint, n_bound: uint)
-> typeck::vtable_origin {
let mut vtable_off = n_bound, i = 0u;
// Vtables are stored in a flat array, finding the right one is
// somewhat awkward
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for vec::each(*ps.bounds) |bounds| {
if i >= n_param { break; }
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for vec::each(*bounds) |bound| {
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match bound { ty::bound_trait(_) => vtable_off += 1u, _ => () }
}
i += 1u;
}
option::get(ps.vtables)[vtable_off]
}
fn resolve_vtables_in_fn_ctxt(fcx: fn_ctxt, vts: typeck::vtable_res)
-> typeck::vtable_res {
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@vec::map(*vts, |d| resolve_vtable_in_fn_ctxt(fcx, d))
}
// Apply the typaram substitutions in the fn_ctxt to a vtable. This should
// eliminate any vtable_params.
fn resolve_vtable_in_fn_ctxt(fcx: fn_ctxt, vt: typeck::vtable_origin)
-> typeck::vtable_origin {
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match vt {
typeck::vtable_static(trait_id, tys, sub) => {
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let tys = match fcx.param_substs {
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Some(substs) => {
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vec::map(tys, |t| ty::subst_tps(fcx.ccx.tcx, substs.tys, t))
}
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_ => tys
};
typeck::vtable_static(trait_id, tys,
resolve_vtables_in_fn_ctxt(fcx, sub))
}
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typeck::vtable_param(n_param, n_bound) => {
match fcx.param_substs {
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Some(substs) => {
find_vtable_in_fn_ctxt(substs, n_param, n_bound)
}
_ => fail ~"resolve_vtable_in_fn_ctxt: no substs"
}
}
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_ => vt
}
}
fn vtable_id(ccx: @crate_ctxt, origin: typeck::vtable_origin) -> mono_id {
match origin {
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typeck::vtable_static(impl_id, substs, sub_vtables) => {
make_mono_id(ccx, impl_id, substs,
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if (*sub_vtables).len() == 0u { None }
else { Some(sub_vtables) }, None)
}
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typeck::vtable_trait(trait_id, substs) => {
@{def: trait_id,
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params: vec::map(substs, |t| mono_precise(t, None))}
}
// can't this be checked at the callee?
_ => fail ~"vtable_id"
}
}
fn get_vtable(ccx: @crate_ctxt, origin: typeck::vtable_origin)
-> ValueRef {
let hash_id = vtable_id(ccx, origin);
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match ccx.vtables.find(hash_id) {
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Some(val) => val,
None => match origin {
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typeck::vtable_static(id, substs, sub_vtables) => {
make_impl_vtable(ccx, id, substs, sub_vtables)
}
_ => fail ~"get_vtable: expected a static origin"
}
}
}
fn make_vtable(ccx: @crate_ctxt, ptrs: ~[ValueRef]) -> ValueRef {
let _icx = ccx.insn_ctxt("impl::make_vtable");
let tbl = C_struct(ptrs);
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let vt_gvar = str::as_c_str(ccx.sess.str_of(ccx.names(~"vtable")), |buf| {
llvm::LLVMAddGlobal(ccx.llmod, val_ty(tbl), buf)
});
llvm::LLVMSetInitializer(vt_gvar, tbl);
llvm::LLVMSetGlobalConstant(vt_gvar, lib::llvm::True);
lib::llvm::SetLinkage(vt_gvar, lib::llvm::InternalLinkage);
vt_gvar
}
fn make_impl_vtable(ccx: @crate_ctxt, impl_id: ast::def_id, substs: ~[ty::t],
vtables: typeck::vtable_res) -> ValueRef {
let _icx = ccx.insn_ctxt("impl::make_impl_vtable");
let tcx = ccx.tcx;
// XXX: This should support multiple traits.
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let trt_id = expect(ccx.sess,
ty::ty_to_def_id(ty::impl_traits(tcx, impl_id)[0]),
|| ~"make_impl_vtable: non-trait-type implemented");
let has_tps = (*ty::lookup_item_type(ccx.tcx, impl_id).bounds).len() > 0u;
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make_vtable(ccx, vec::map(*ty::trait_methods(tcx, trt_id), |im| {
let fty = ty::subst_tps(tcx, substs, ty::mk_fn(tcx, im.fty));
if (*im.tps).len() > 0u || ty::type_has_self(fty) {
C_null(T_ptr(T_nil()))
} else {
let mut m_id = method_with_name(ccx, impl_id, im.ident);
if has_tps {
// If the method is in another crate, need to make an inlined
// copy first
if m_id.crate != ast::local_crate {
m_id = maybe_instantiate_inline(ccx, m_id);
}
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monomorphic_fn(ccx, m_id, substs, Some(vtables), None).val
} else if m_id.crate == ast::local_crate {
get_item_val(ccx, m_id.node)
} else {
trans_external_path(ccx, m_id, fty)
}
}
}))
}
fn trans_cast(bcx: block, val: @ast::expr, id: ast::node_id, dest: dest)
-> block {
let _icx = bcx.insn_ctxt("impl::trans_cast");
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if dest == ignore { return trans_expr(bcx, val, ignore); }
let ccx = bcx.ccx();
let v_ty = expr_ty(bcx, val);
let {bcx: bcx, box: llbox, body: body} = malloc_boxed(bcx, v_ty);
add_clean_free(bcx, llbox, heap_shared);
let bcx = trans_expr_save_in(bcx, val, body);
revoke_clean(bcx, llbox);
let result = get_dest_addr(dest);
Store(bcx, llbox, PointerCast(bcx, GEPi(bcx, result, ~[0u, 1u]),
T_ptr(val_ty(llbox))));
let orig = ccx.maps.vtable_map.get(id)[0];
let orig = resolve_vtable_in_fn_ctxt(bcx.fcx, orig);
let vtable = get_vtable(bcx.ccx(), orig);
Store(bcx, vtable, PointerCast(bcx, GEPi(bcx, result, ~[0u, 0u]),
T_ptr(val_ty(vtable))));
bcx
}