rust/src/librustc_trans/trans/callee.rs

1145 lines
44 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.
//! Handles translation of callees as well as other call-related
//! things. Callees are a superset of normal rust values and sometimes
//! have different representations. In particular, top-level fn items
//! and methods are represented as just a fn ptr and not a full
//! closure.
pub use self::AutorefArg::*;
pub use self::CalleeData::*;
pub use self::CallArgs::*;
use arena::TypedArena;
use back::link;
use session;
use llvm::{ValueRef};
use llvm::get_param;
use llvm;
use metadata::csearch;
use middle::def;
use middle::subst;
use middle::subst::{Subst, Substs};
use trans::adt;
use trans::base;
use trans::base::*;
use trans::build::*;
use trans::callee;
use trans::cleanup;
use trans::cleanup::CleanupMethods;
use trans::closure;
use trans::common::{self, Block, Result, NodeIdAndSpan, ExprId, CrateContext,
ExprOrMethodCall, FunctionContext, MethodCallKey};
use trans::consts;
use trans::datum::*;
use trans::debuginfo::{DebugLoc, ToDebugLoc};
use trans::expr;
use trans::glue;
use trans::inline;
use trans::foreign;
use trans::intrinsic;
use trans::meth;
use trans::monomorphize;
use trans::type_::Type;
use trans::type_of;
use middle::ty::{self, Ty};
use middle::ty::MethodCall;
use util::ppaux::Repr;
use util::ppaux::ty_to_string;
use syntax::abi as synabi;
use syntax::ast;
use syntax::ast_map;
use syntax::ptr::P;
#[derive(Copy)]
pub struct MethodData {
pub llfn: ValueRef,
pub llself: ValueRef,
}
pub enum CalleeData<'tcx> {
// Constructor for enum variant/tuple-like-struct
// i.e. Some, Ok
NamedTupleConstructor(subst::Substs<'tcx>, ty::Disr),
// Represents a (possibly monomorphized) top-level fn item or method
// item. Note that this is just the fn-ptr and is not a Rust closure
// value (which is a pair).
Fn(/* llfn */ ValueRef),
Intrinsic(ast::NodeId, subst::Substs<'tcx>),
TraitItem(MethodData)
}
pub struct Callee<'blk, 'tcx: 'blk> {
pub bcx: Block<'blk, 'tcx>,
pub data: CalleeData<'tcx>,
}
fn trans<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, expr: &ast::Expr)
-> Callee<'blk, 'tcx> {
let _icx = push_ctxt("trans_callee");
debug!("callee::trans(expr={})", expr.repr(bcx.tcx()));
// pick out special kinds of expressions that can be called:
match expr.node {
ast::ExprPath(_) | ast::ExprQPath(_) => {
return trans_def(bcx, bcx.def(expr.id), expr);
}
_ => {}
}
// any other expressions are closures:
return datum_callee(bcx, expr);
fn datum_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, expr: &ast::Expr)
-> Callee<'blk, 'tcx> {
let DatumBlock { bcx, datum, .. } = expr::trans(bcx, expr);
match datum.ty.sty {
ty::ty_bare_fn(..) => {
let llval = datum.to_llscalarish(bcx);
return Callee {
bcx: bcx,
data: Fn(llval),
};
}
_ => {
bcx.tcx().sess.span_bug(
expr.span,
&format!("type of callee is neither bare-fn nor closure: \
{}",
bcx.ty_to_string(datum.ty))[]);
}
}
}
fn fn_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, llfn: ValueRef)
-> Callee<'blk, 'tcx> {
return Callee {
bcx: bcx,
data: Fn(llfn),
};
}
fn trans_def<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
def: def::Def,
ref_expr: &ast::Expr)
-> Callee<'blk, 'tcx> {
debug!("trans_def(def={}, ref_expr={})", def.repr(bcx.tcx()), ref_expr.repr(bcx.tcx()));
let expr_ty = common::node_id_type(bcx, ref_expr.id);
match def {
def::DefFn(did, _) if {
let maybe_def_id = inline::get_local_instance(bcx.ccx(), did);
let maybe_ast_node = maybe_def_id.and_then(|def_id| bcx.tcx().map
.find(def_id.node));
match maybe_ast_node {
Some(ast_map::NodeStructCtor(_)) => true,
_ => false
}
} => {
let substs = common::node_id_substs(bcx.ccx(),
ExprId(ref_expr.id),
bcx.fcx.param_substs);
Callee {
bcx: bcx,
data: NamedTupleConstructor(substs, 0)
}
}
def::DefFn(did, _) if match expr_ty.sty {
ty::ty_bare_fn(_, ref f) => f.abi == synabi::RustIntrinsic,
_ => false
} => {
let substs = common::node_id_substs(bcx.ccx(),
ExprId(ref_expr.id),
bcx.fcx.param_substs);
let def_id = inline::maybe_instantiate_inline(bcx.ccx(), did);
Callee { bcx: bcx, data: Intrinsic(def_id.node, substs) }
}
def::DefFn(did, _) | def::DefMethod(did, _, def::FromImpl(_)) |
def::DefStaticMethod(did, def::FromImpl(_)) => {
fn_callee(bcx, trans_fn_ref(bcx.ccx(), did, ExprId(ref_expr.id),
bcx.fcx.param_substs).val)
}
def::DefStaticMethod(meth_did, def::FromTrait(trait_did)) |
def::DefMethod(meth_did, _, def::FromTrait(trait_did)) => {
fn_callee(bcx, meth::trans_static_method_callee(bcx.ccx(),
meth_did,
trait_did,
ref_expr.id,
bcx.fcx.param_substs).val)
}
def::DefVariant(tid, vid, _) => {
let vinfo = ty::enum_variant_with_id(bcx.tcx(), tid, vid);
let substs = common::node_id_substs(bcx.ccx(),
ExprId(ref_expr.id),
bcx.fcx.param_substs);
// Nullary variants are not callable
assert!(vinfo.args.len() > 0);
Callee {
bcx: bcx,
data: NamedTupleConstructor(substs, vinfo.disr_val)
}
}
def::DefStruct(_) => {
let substs = common::node_id_substs(bcx.ccx(),
ExprId(ref_expr.id),
bcx.fcx.param_substs);
Callee {
bcx: bcx,
data: NamedTupleConstructor(substs, 0)
}
}
def::DefStatic(..) |
def::DefConst(..) |
def::DefLocal(..) |
def::DefUpvar(..) => {
datum_callee(bcx, ref_expr)
}
def::DefMod(..) | def::DefForeignMod(..) | def::DefTrait(..) |
def::DefTy(..) | def::DefPrimTy(..) | def::DefAssociatedTy(..) |
def::DefUse(..) | def::DefTyParamBinder(..) |
def::DefRegion(..) | def::DefLabel(..) | def::DefTyParam(..) |
def::DefSelfTy(..) | def::DefAssociatedPath(..) => {
bcx.tcx().sess.span_bug(
ref_expr.span,
&format!("cannot translate def {:?} \
to a callable thing!", def)[]);
}
}
}
}
/// Translates a reference (with id `ref_id`) to the fn/method with id `def_id` into a function
/// pointer. This may require monomorphization or inlining.
pub fn trans_fn_ref<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
def_id: ast::DefId,
node: ExprOrMethodCall,
param_substs: &'tcx subst::Substs<'tcx>)
-> Datum<'tcx, Rvalue> {
let _icx = push_ctxt("trans_fn_ref");
let substs = common::node_id_substs(ccx, node, param_substs);
debug!("trans_fn_ref(def_id={}, node={:?}, substs={})",
def_id.repr(ccx.tcx()),
node,
substs.repr(ccx.tcx()));
trans_fn_ref_with_substs(ccx, def_id, node, param_substs, substs)
}
fn trans_fn_ref_with_substs_to_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
def_id: ast::DefId,
ref_id: ast::NodeId,
substs: subst::Substs<'tcx>)
-> Callee<'blk, 'tcx> {
Callee {
bcx: bcx,
data: Fn(trans_fn_ref_with_substs(bcx.ccx(),
def_id,
ExprId(ref_id),
bcx.fcx.param_substs,
substs).val),
}
}
/// Translates an adapter that implements the `Fn` trait for a fn
/// pointer. This is basically the equivalent of something like:
///
/// ```rust
/// impl<'a> Fn(&'a int) -> &'a int for fn(&int) -> &int {
/// extern "rust-abi" fn call(&self, args: (&'a int,)) -> &'a int {
/// (*self)(args.0)
/// }
/// }
/// ```
///
/// but for the bare function type given.
pub fn trans_fn_pointer_shim<'a, 'tcx>(
ccx: &'a CrateContext<'a, 'tcx>,
bare_fn_ty: Ty<'tcx>)
-> ValueRef
{
let _icx = push_ctxt("trans_fn_pointer_shim");
let tcx = ccx.tcx();
let bare_fn_ty = common::erase_regions(tcx, &bare_fn_ty);
match ccx.fn_pointer_shims().borrow().get(&bare_fn_ty) {
Some(&llval) => { return llval; }
None => { }
}
debug!("trans_fn_pointer_shim(bare_fn_ty={})",
bare_fn_ty.repr(tcx));
// This is an impl of `Fn` trait, so receiver is `&self`.
let bare_fn_ty_ref = ty::mk_imm_rptr(tcx, tcx.mk_region(ty::ReStatic), bare_fn_ty);
// Construct the "tuply" version of `bare_fn_ty`. It takes two arguments: `self`,
// which is the fn pointer, and `args`, which is the arguments tuple.
let (opt_def_id, sig) =
match bare_fn_ty.sty {
ty::ty_bare_fn(opt_def_id,
&ty::BareFnTy { unsafety: ast::Unsafety::Normal,
abi: synabi::Rust,
ref sig }) => {
(opt_def_id, sig)
}
_ => {
tcx.sess.bug(&format!("trans_fn_pointer_shim invoked on invalid type: {}",
bare_fn_ty.repr(tcx))[]);
}
};
let sig = ty::erase_late_bound_regions(tcx, sig);
let tuple_input_ty = ty::mk_tup(tcx, sig.inputs.to_vec());
let tuple_fn_ty = ty::mk_bare_fn(tcx,
opt_def_id,
tcx.mk_bare_fn(ty::BareFnTy {
unsafety: ast::Unsafety::Normal,
abi: synabi::RustCall,
sig: ty::Binder(ty::FnSig {
inputs: vec![bare_fn_ty_ref,
tuple_input_ty],
output: sig.output,
variadic: false
})}));
debug!("tuple_fn_ty: {}", tuple_fn_ty.repr(tcx));
//
let function_name =
link::mangle_internal_name_by_type_and_seq(ccx, bare_fn_ty,
"fn_pointer_shim");
let llfn =
decl_internal_rust_fn(ccx,
tuple_fn_ty,
&function_name[]);
//
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 ptr to the the fn pointer
let llfnpointer =
Load(bcx, get_param(fcx.llfn, fcx.arg_pos(0) as u32));
// the remaining arguments will be the untupled values
let llargs: Vec<_> =
sig.inputs.iter()
.enumerate()
.map(|(i, _)| get_param(fcx.llfn, fcx.arg_pos(i+1) as u32))
.collect();
assert!(!fcx.needs_ret_allocas);
let dest = fcx.llretslotptr.get().map(|_|
expr::SaveIn(fcx.get_ret_slot(bcx, sig.output, "ret_slot"))
);
bcx = trans_call_inner(bcx,
DebugLoc::None,
bare_fn_ty,
|bcx, _| Callee { bcx: bcx, data: Fn(llfnpointer) },
ArgVals(&llargs[]),
dest).bcx;
finish_fn(&fcx, bcx, sig.output, DebugLoc::None);
ccx.fn_pointer_shims().borrow_mut().insert(bare_fn_ty, llfn);
llfn
}
/// Translates a reference to a fn/method item, monomorphizing and
/// inlining as it goes.
///
/// # Parameters
///
/// - `ccx`: the crate context
/// - `def_id`: def id of the fn or method item being referenced
/// - `node`: node id of the reference to the fn/method, if applicable.
/// This parameter may be zero; but, if so, the resulting value may not
/// have the right type, so it must be cast before being used.
/// - `param_substs`: if the `node` is in a polymorphic function, these
/// are the substitutions required to monomorphize its type
/// - `substs`: values for each of the fn/method's parameters
pub fn trans_fn_ref_with_substs<'a, 'tcx>(
ccx: &CrateContext<'a, 'tcx>,
def_id: ast::DefId,
node: ExprOrMethodCall,
param_substs: &'tcx subst::Substs<'tcx>,
substs: subst::Substs<'tcx>)
-> Datum<'tcx, Rvalue>
{
let _icx = push_ctxt("trans_fn_ref_with_substs");
let tcx = ccx.tcx();
debug!("trans_fn_ref_with_substs(def_id={}, node={:?}, \
param_substs={}, substs={})",
def_id.repr(tcx),
node,
param_substs.repr(tcx),
substs.repr(tcx));
assert!(substs.types.all(|t| !ty::type_needs_infer(*t)));
assert!(substs.types.all(|t| !ty::type_has_escaping_regions(*t)));
let substs = substs.erase_regions();
// Load the info for the appropriate trait if necessary.
match ty::trait_of_item(tcx, def_id) {
None => {}
Some(trait_id) => {
ty::populate_implementations_for_trait_if_necessary(tcx, trait_id)
}
}
// We need to do a bunch of special handling for default methods.
// We need to modify the def_id and our substs in order to monomorphize
// the function.
let (is_default, def_id, substs) = match ty::provided_source(tcx, def_id) {
None => {
(false, def_id, tcx.mk_substs(substs))
}
Some(source_id) => {
// There are two relevant substitutions when compiling
// default methods. First, there is the substitution for
// the type parameters of the impl we are using and the
// method we are calling. This substitution is the substs
// argument we already have.
// In order to compile a default method, though, we need
// to consider another substitution: the substitution for
// the type parameters on trait; the impl we are using
// implements the trait at some particular type
// parameters, and we need to substitute for those first.
// So, what we need to do is find this substitution and
// compose it with the one we already have.
let impl_id = ty::impl_or_trait_item(tcx, def_id).container()
.id();
let impl_or_trait_item = ty::impl_or_trait_item(tcx, source_id);
match impl_or_trait_item {
ty::MethodTraitItem(method) => {
let trait_ref = ty::impl_trait_ref(tcx, impl_id).unwrap();
// Compute the first substitution
let first_subst =
ty::make_substs_for_receiver_types(tcx, &*trait_ref, &*method)
.erase_regions();
// And compose them
let new_substs = tcx.mk_substs(first_subst.subst(tcx, &substs));
debug!("trans_fn_with_vtables - default method: \
substs = {}, trait_subst = {}, \
first_subst = {}, new_subst = {}",
substs.repr(tcx), trait_ref.substs.repr(tcx),
first_subst.repr(tcx), new_substs.repr(tcx));
(true, source_id, new_substs)
}
ty::TypeTraitItem(_) => {
tcx.sess.bug("trans_fn_ref_with_vtables() tried \
to translate an associated type?!")
}
}
}
};
// If this is a closure, redirect to it.
match closure::get_or_create_declaration_if_closure(ccx, def_id, substs) {
None => {}
Some(llfn) => return llfn,
}
// Check whether this fn has an inlined copy and, if so, redirect
// def_id to the local id of the inlined copy.
let def_id = inline::maybe_instantiate_inline(ccx, def_id);
// We must monomorphise if the fn has type parameters, is a default method,
// or is a named tuple constructor.
let must_monomorphise = if !substs.types.is_empty() || is_default {
true
} else if def_id.krate == ast::LOCAL_CRATE {
let map_node = session::expect(
ccx.sess(),
tcx.map.find(def_id.node),
|| "local item should be in ast map".to_string());
match map_node {
ast_map::NodeVariant(v) => match v.node.kind {
ast::TupleVariantKind(ref args) => args.len() > 0,
_ => false
},
ast_map::NodeStructCtor(_) => true,
_ => false
}
} else {
false
};
// Create a monomorphic version of generic functions
if must_monomorphise {
// Should be either intra-crate or inlined.
assert_eq!(def_id.krate, ast::LOCAL_CRATE);
let opt_ref_id = match node {
ExprId(id) => if id != 0 { Some(id) } else { None },
MethodCallKey(_) => None,
};
let (val, fn_ty, must_cast) =
monomorphize::monomorphic_fn(ccx, def_id, substs, opt_ref_id);
if must_cast && node != ExprId(0) {
// Monotype of the REFERENCE to the function (type params
// are subst'd)
let ref_ty = match node {
ExprId(id) => ty::node_id_to_type(tcx, id),
MethodCallKey(method_call) => {
(*tcx.method_map.borrow())[method_call].ty
}
};
let ref_ty = monomorphize::apply_param_substs(tcx,
param_substs,
&ref_ty);
let llptrty = type_of::type_of_fn_from_ty(ccx, ref_ty).ptr_to();
if llptrty != common::val_ty(val) {
let val = consts::ptrcast(val, llptrty);
return Datum::new(val, ref_ty, Rvalue::new(ByValue));
}
}
return Datum::new(val, fn_ty, Rvalue::new(ByValue));
}
// Type scheme of the function item (may have type params)
let fn_type_scheme = ty::lookup_item_type(tcx, def_id);
let fn_type = monomorphize::normalize_associated_type(tcx, &fn_type_scheme.ty);
// Find the actual function pointer.
let mut val = {
if def_id.krate == ast::LOCAL_CRATE {
// Internal reference.
get_item_val(ccx, def_id.node)
} else {
// External reference.
trans_external_path(ccx, def_id, fn_type)
}
};
// This is subtle and surprising, but sometimes we have to bitcast
// the resulting fn pointer. The reason has to do with external
// functions. If you have two crates that both bind the same C
// library, they may not use precisely the same types: for
// example, they will probably each declare their own structs,
// which are distinct types from LLVM's point of view (nominal
// types).
//
// Now, if those two crates are linked into an application, and
// they contain inlined code, you can wind up with a situation
// where both of those functions wind up being loaded into this
// application simultaneously. In that case, the same function
// (from LLVM's point of view) requires two types. But of course
// LLVM won't allow one function to have two types.
//
// What we currently do, therefore, is declare the function with
// one of the two types (whichever happens to come first) and then
// bitcast as needed when the function is referenced to make sure
// it has the type we expect.
//
// This can occur on either a crate-local or crate-external
// reference. It also occurs when testing libcore and in some
// other weird situations. Annoying.
let llty = type_of::type_of_fn_from_ty(ccx, fn_type);
let llptrty = llty.ptr_to();
if common::val_ty(val) != llptrty {
debug!("trans_fn_ref_with_vtables(): casting pointer!");
val = consts::ptrcast(val, llptrty);
} else {
debug!("trans_fn_ref_with_vtables(): not casting pointer!");
}
Datum::new(val, fn_type, Rvalue::new(ByValue))
}
// ______________________________________________________________________
// Translating calls
pub fn trans_call<'a, 'blk, 'tcx>(in_cx: Block<'blk, 'tcx>,
call_expr: &ast::Expr,
f: &ast::Expr,
args: CallArgs<'a, 'tcx>,
dest: expr::Dest)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_call");
trans_call_inner(in_cx,
call_expr.debug_loc(),
common::expr_ty_adjusted(in_cx, f),
|cx, _| trans(cx, f),
args,
Some(dest)).bcx
}
pub fn trans_method_call<'a, 'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
call_expr: &ast::Expr,
rcvr: &ast::Expr,
args: CallArgs<'a, 'tcx>,
dest: expr::Dest)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_method_call");
debug!("trans_method_call(call_expr={})", call_expr.repr(bcx.tcx()));
let method_call = MethodCall::expr(call_expr.id);
let method_ty = (*bcx.tcx().method_map.borrow())[method_call].ty;
trans_call_inner(
bcx,
call_expr.debug_loc(),
common::monomorphize_type(bcx, method_ty),
|cx, arg_cleanup_scope| {
meth::trans_method_callee(cx, method_call, Some(rcvr), arg_cleanup_scope)
},
args,
Some(dest)).bcx
}
pub fn trans_lang_call<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
did: ast::DefId,
args: &[ValueRef],
dest: Option<expr::Dest>,
debug_loc: DebugLoc)
-> Result<'blk, 'tcx> {
let fty = if did.krate == ast::LOCAL_CRATE {
ty::node_id_to_type(bcx.tcx(), did.node)
} else {
csearch::get_type(bcx.tcx(), did).ty
};
callee::trans_call_inner(bcx,
debug_loc,
fty,
|bcx, _| {
trans_fn_ref_with_substs_to_callee(bcx,
did,
0,
subst::Substs::trans_empty())
},
ArgVals(args),
dest)
}
/// This behemoth of a function translates function calls. Unfortunately, in order to generate more
/// efficient LLVM output at -O0, it has quite a complex signature (refactoring this into two
/// functions seems like a good idea).
///
/// In particular, for lang items, it is invoked with a dest of None, and in that case the return
/// value contains the result of the fn. The lang item must not return a structural type or else
/// all heck breaks loose.
///
/// For non-lang items, `dest` is always Some, and hence the result is written into memory
/// somewhere. Nonetheless we return the actual return value of the function.
pub fn trans_call_inner<'a, 'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>,
debug_loc: DebugLoc,
callee_ty: Ty<'tcx>,
get_callee: F,
args: CallArgs<'a, 'tcx>,
dest: Option<expr::Dest>)
-> Result<'blk, 'tcx> where
F: FnOnce(Block<'blk, 'tcx>, cleanup::ScopeId) -> Callee<'blk, 'tcx>,
{
// Introduce a temporary cleanup scope that will contain cleanups
// for the arguments while they are being evaluated. The purpose
// this cleanup is to ensure that, should a panic occur while
// evaluating argument N, the values for arguments 0...N-1 are all
// cleaned up. If no panic occurs, the values are handed off to
// the callee, and hence none of the cleanups in this temporary
// scope will ever execute.
let fcx = bcx.fcx;
let ccx = fcx.ccx;
let arg_cleanup_scope = fcx.push_custom_cleanup_scope();
let callee = get_callee(bcx, cleanup::CustomScope(arg_cleanup_scope));
let mut bcx = callee.bcx;
let (abi, ret_ty) = match callee_ty.sty {
ty::ty_bare_fn(_, ref f) => {
let output = ty::erase_late_bound_regions(bcx.tcx(), &f.sig.output());
(f.abi, output)
}
_ => panic!("expected bare rust fn or closure in trans_call_inner")
};
let (llfn, llenv, llself) = match callee.data {
Fn(llfn) => {
(llfn, None, None)
}
TraitItem(d) => {
(d.llfn, None, Some(d.llself))
}
Intrinsic(node, substs) => {
assert!(abi == synabi::RustIntrinsic);
assert!(dest.is_some());
let call_info = match debug_loc {
DebugLoc::At(id, span) => NodeIdAndSpan { id: id, span: span },
DebugLoc::None => {
bcx.sess().bug("No call info for intrinsic call?")
}
};
return intrinsic::trans_intrinsic_call(bcx, node, callee_ty,
arg_cleanup_scope, args,
dest.unwrap(), substs,
call_info);
}
NamedTupleConstructor(substs, disr) => {
assert!(dest.is_some());
fcx.pop_custom_cleanup_scope(arg_cleanup_scope);
let ctor_ty = callee_ty.subst(bcx.tcx(), &substs);
return base::trans_named_tuple_constructor(bcx,
ctor_ty,
disr,
args,
dest.unwrap(),
debug_loc);
}
};
// Intrinsics should not become actual functions.
// We trans them in place in `trans_intrinsic_call`
assert!(abi != synabi::RustIntrinsic);
let is_rust_fn = abi == synabi::Rust || abi == synabi::RustCall;
// Generate a location to store the result. If the user does
// not care about the result, just make a stack slot.
let opt_llretslot = dest.and_then(|dest| match dest {
expr::SaveIn(dst) => Some(dst),
expr::Ignore => {
let ret_ty = match ret_ty {
ty::FnConverging(ret_ty) => ret_ty,
ty::FnDiverging => ty::mk_nil(ccx.tcx())
};
if !is_rust_fn ||
type_of::return_uses_outptr(ccx, ret_ty) ||
common::type_needs_drop(bcx.tcx(), ret_ty) {
// Push the out-pointer if we use an out-pointer for this
// return type, otherwise push "undef".
if common::type_is_zero_size(ccx, ret_ty) {
let llty = type_of::type_of(ccx, ret_ty);
Some(common::C_undef(llty.ptr_to()))
} else {
Some(alloc_ty(bcx, ret_ty, "__llret"))
}
} else {
None
}
}
});
let mut llresult = unsafe {
llvm::LLVMGetUndef(Type::nil(ccx).ptr_to().to_ref())
};
// The code below invokes the function, using either the Rust
// conventions (if it is a rust fn) or the native conventions
// (otherwise). The important part is that, when all is said
// and done, either the return value of the function will have been
// written in opt_llretslot (if it is Some) or `llresult` will be
// set appropriately (otherwise).
if is_rust_fn {
let mut llargs = Vec::new();
if let (ty::FnConverging(ret_ty), Some(llretslot)) = (ret_ty, opt_llretslot) {
if type_of::return_uses_outptr(ccx, ret_ty) {
llargs.push(llretslot);
}
}
// Push the environment (or a trait object's self).
match (llenv, llself) {
(Some(llenv), None) => llargs.push(llenv),
(None, Some(llself)) => llargs.push(llself),
_ => {}
}
// Push the arguments.
bcx = trans_args(bcx,
args,
callee_ty,
&mut llargs,
cleanup::CustomScope(arg_cleanup_scope),
llself.is_some(),
abi);
fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
// Invoke the actual rust fn and update bcx/llresult.
let (llret, b) = base::invoke(bcx,
llfn,
&llargs[],
callee_ty,
debug_loc);
bcx = b;
llresult = llret;
// If the Rust convention for this type is return via
// the return value, copy it into llretslot.
match (opt_llretslot, ret_ty) {
(Some(llretslot), ty::FnConverging(ret_ty)) => {
if !type_of::return_uses_outptr(bcx.ccx(), ret_ty) &&
!common::type_is_zero_size(bcx.ccx(), ret_ty)
{
store_ty(bcx, llret, llretslot, ret_ty)
}
}
(_, _) => {}
}
} else {
// Lang items are the only case where dest is None, and
// they are always Rust fns.
assert!(dest.is_some());
let mut llargs = Vec::new();
let arg_tys = match args {
ArgExprs(a) => a.iter().map(|x| common::expr_ty(bcx, &**x)).collect(),
_ => panic!("expected arg exprs.")
};
bcx = trans_args(bcx,
args,
callee_ty,
&mut llargs,
cleanup::CustomScope(arg_cleanup_scope),
false,
abi);
fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
bcx = foreign::trans_native_call(bcx,
callee_ty,
llfn,
opt_llretslot.unwrap(),
&llargs[],
arg_tys,
debug_loc);
}
fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_cleanup_scope);
// If the caller doesn't care about the result of this fn call,
// drop the temporary slot we made.
match (dest, opt_llretslot, ret_ty) {
(Some(expr::Ignore), Some(llretslot), ty::FnConverging(ret_ty)) => {
// drop the value if it is not being saved.
bcx = glue::drop_ty(bcx,
llretslot,
ret_ty,
debug_loc);
call_lifetime_end(bcx, llretslot);
}
_ => {}
}
if ret_ty == ty::FnDiverging {
Unreachable(bcx);
}
Result::new(bcx, llresult)
}
pub enum CallArgs<'a, 'tcx> {
// Supply value of arguments as a list of expressions that must be
// translated. This is used in the common case of `foo(bar, qux)`.
ArgExprs(&'a [P<ast::Expr>]),
// Supply value of arguments as a list of LLVM value refs; frequently
// used with lang items and so forth, when the argument is an internal
// value.
ArgVals(&'a [ValueRef]),
// For overloaded operators: `(lhs, Vec(rhs, rhs_id), autoref)`. `lhs`
// is the left-hand-side and `rhs/rhs_id` is the datum/expr-id of
// the right-hand-side arguments (if any). `autoref` indicates whether the `rhs`
// arguments should be auto-referenced
ArgOverloadedOp(Datum<'tcx, Expr>, Vec<(Datum<'tcx, Expr>, ast::NodeId)>, bool),
// Supply value of arguments as a list of expressions that must be
// translated, for overloaded call operators.
ArgOverloadedCall(Vec<&'a ast::Expr>),
}
fn trans_args_under_call_abi<'blk, 'tcx>(
mut bcx: Block<'blk, 'tcx>,
arg_exprs: &[P<ast::Expr>],
fn_ty: Ty<'tcx>,
llargs: &mut Vec<ValueRef>,
arg_cleanup_scope: cleanup::ScopeId,
ignore_self: bool)
-> Block<'blk, 'tcx>
{
let args =
ty::erase_late_bound_regions(
bcx.tcx(), &ty::ty_fn_args(fn_ty));
// Translate the `self` argument first.
if !ignore_self {
let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &*arg_exprs[0]));
llargs.push(unpack_result!(bcx, {
trans_arg_datum(bcx,
args[0],
arg_datum,
arg_cleanup_scope,
DontAutorefArg)
}))
}
// Now untuple the rest of the arguments.
let tuple_expr = &arg_exprs[1];
let tuple_type = common::node_id_type(bcx, tuple_expr.id);
match tuple_type.sty {
ty::ty_tup(ref field_types) => {
let tuple_datum = unpack_datum!(bcx,
expr::trans(bcx, &**tuple_expr));
let tuple_lvalue_datum =
unpack_datum!(bcx,
tuple_datum.to_lvalue_datum(bcx,
"args",
tuple_expr.id));
let repr = adt::represent_type(bcx.ccx(), tuple_type);
let repr_ptr = &*repr;
for i in 0..field_types.len() {
let arg_datum = tuple_lvalue_datum.get_element(
bcx,
field_types[i],
|srcval| {
adt::trans_field_ptr(bcx, repr_ptr, srcval, 0, i)
});
let arg_datum = arg_datum.to_expr_datum();
let arg_datum =
unpack_datum!(bcx, arg_datum.to_rvalue_datum(bcx, "arg"));
let arg_datum =
unpack_datum!(bcx, arg_datum.to_appropriate_datum(bcx));
llargs.push(arg_datum.add_clean(bcx.fcx, arg_cleanup_scope));
}
}
_ => {
bcx.sess().span_bug(tuple_expr.span,
"argument to `.call()` wasn't a tuple?!")
}
};
bcx
}
fn trans_overloaded_call_args<'blk, 'tcx>(
mut bcx: Block<'blk, 'tcx>,
arg_exprs: Vec<&ast::Expr>,
fn_ty: Ty<'tcx>,
llargs: &mut Vec<ValueRef>,
arg_cleanup_scope: cleanup::ScopeId,
ignore_self: bool)
-> Block<'blk, 'tcx> {
// Translate the `self` argument first.
let arg_tys = ty::erase_late_bound_regions(bcx.tcx(), &ty::ty_fn_args(fn_ty));
if !ignore_self {
let arg_datum = unpack_datum!(bcx, expr::trans(bcx, arg_exprs[0]));
llargs.push(unpack_result!(bcx, {
trans_arg_datum(bcx,
arg_tys[0],
arg_datum,
arg_cleanup_scope,
DontAutorefArg)
}))
}
// Now untuple the rest of the arguments.
let tuple_type = arg_tys[1];
match tuple_type.sty {
ty::ty_tup(ref field_types) => {
for (i, &field_type) in field_types.iter().enumerate() {
let arg_datum =
unpack_datum!(bcx, expr::trans(bcx, arg_exprs[i + 1]));
llargs.push(unpack_result!(bcx, {
trans_arg_datum(bcx,
field_type,
arg_datum,
arg_cleanup_scope,
DontAutorefArg)
}))
}
}
_ => {
bcx.sess().span_bug(arg_exprs[0].span,
"argument to `.call()` wasn't a tuple?!")
}
};
bcx
}
pub fn trans_args<'a, 'blk, 'tcx>(cx: Block<'blk, 'tcx>,
args: CallArgs<'a, 'tcx>,
fn_ty: Ty<'tcx>,
llargs: &mut Vec<ValueRef>,
arg_cleanup_scope: cleanup::ScopeId,
ignore_self: bool,
abi: synabi::Abi)
-> Block<'blk, 'tcx> {
debug!("trans_args(abi={})", abi);
let _icx = push_ctxt("trans_args");
let arg_tys = ty::erase_late_bound_regions(cx.tcx(), &ty::ty_fn_args(fn_ty));
let variadic = ty::fn_is_variadic(fn_ty);
let mut bcx = cx;
// First we figure out the caller's view of the types of the arguments.
// This will be needed if this is a generic call, because the callee has
// to cast her view of the arguments to the caller's view.
match args {
ArgExprs(arg_exprs) => {
if abi == synabi::RustCall {
// This is only used for direct calls to the `call`,
// `call_mut` or `call_once` functions.
return trans_args_under_call_abi(cx,
arg_exprs,
fn_ty,
llargs,
arg_cleanup_scope,
ignore_self)
}
let num_formal_args = arg_tys.len();
for (i, arg_expr) in arg_exprs.iter().enumerate() {
if i == 0 && ignore_self {
continue;
}
let arg_ty = if i >= num_formal_args {
assert!(variadic);
common::expr_ty_adjusted(cx, &**arg_expr)
} else {
arg_tys[i]
};
let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &**arg_expr));
llargs.push(unpack_result!(bcx, {
trans_arg_datum(bcx, arg_ty, arg_datum,
arg_cleanup_scope,
DontAutorefArg)
}));
}
}
ArgOverloadedCall(arg_exprs) => {
return trans_overloaded_call_args(cx,
arg_exprs,
fn_ty,
llargs,
arg_cleanup_scope,
ignore_self)
}
ArgOverloadedOp(lhs, rhs, autoref) => {
assert!(!variadic);
llargs.push(unpack_result!(bcx, {
trans_arg_datum(bcx, arg_tys[0], lhs,
arg_cleanup_scope,
DontAutorefArg)
}));
assert_eq!(arg_tys.len(), 1 + rhs.len());
for (rhs, rhs_id) in rhs {
llargs.push(unpack_result!(bcx, {
trans_arg_datum(bcx, arg_tys[1], rhs,
arg_cleanup_scope,
if autoref { DoAutorefArg(rhs_id) } else { DontAutorefArg })
}));
}
}
ArgVals(vs) => {
llargs.push_all(vs);
}
}
bcx
}
#[derive(Copy)]
pub enum AutorefArg {
DontAutorefArg,
DoAutorefArg(ast::NodeId)
}
pub fn trans_arg_datum<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
formal_arg_ty: Ty<'tcx>,
arg_datum: Datum<'tcx, Expr>,
arg_cleanup_scope: cleanup::ScopeId,
autoref_arg: AutorefArg)
-> Result<'blk, 'tcx> {
let _icx = push_ctxt("trans_arg_datum");
let mut bcx = bcx;
let ccx = bcx.ccx();
debug!("trans_arg_datum({})",
formal_arg_ty.repr(bcx.tcx()));
let arg_datum_ty = arg_datum.ty;
debug!(" arg datum: {}", arg_datum.to_string(bcx.ccx()));
let mut val;
// FIXME(#3548) use the adjustments table
match autoref_arg {
DoAutorefArg(arg_id) => {
// We will pass argument by reference
// We want an lvalue, so that we can pass by reference and
let arg_datum = unpack_datum!(
bcx, arg_datum.to_lvalue_datum(bcx, "arg", arg_id));
val = arg_datum.val;
}
DontAutorefArg => {
// Make this an rvalue, since we are going to be
// passing ownership.
let arg_datum = unpack_datum!(
bcx, arg_datum.to_rvalue_datum(bcx, "arg"));
// Now that arg_datum is owned, get it into the appropriate
// mode (ref vs value).
let arg_datum = unpack_datum!(
bcx, arg_datum.to_appropriate_datum(bcx));
// Technically, ownership of val passes to the callee.
// However, we must cleanup should we panic before the
// callee is actually invoked.
val = arg_datum.add_clean(bcx.fcx, arg_cleanup_scope);
}
}
if formal_arg_ty != arg_datum_ty {
// this could happen due to e.g. subtyping
let llformal_arg_ty = type_of::type_of_explicit_arg(ccx, formal_arg_ty);
debug!("casting actual type ({}) to match formal ({})",
bcx.val_to_string(val), bcx.llty_str(llformal_arg_ty));
debug!("Rust types: {}; {}", ty_to_string(bcx.tcx(), arg_datum_ty),
ty_to_string(bcx.tcx(), formal_arg_ty));
val = PointerCast(bcx, val, llformal_arg_ty);
}
debug!("--- trans_arg_datum passing {}", bcx.val_to_string(val));
Result::new(bcx, val)
}