rust/src/librustc_trans/trans/callee.rs

977 lines
37 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::CalleeData::*;
pub use self::CallArgs::*;
use arena::TypedArena;
use back::link;
use llvm::{self, ValueRef, get_params};
use middle::cstore::LOCAL_CRATE;
use middle::def_id::DefId;
use middle::infer;
use middle::subst;
use middle::subst::{Substs};
use rustc::front::map as hir_map;
use trans::adt;
use trans::base;
use trans::base::*;
use trans::build::*;
use trans::cleanup;
use trans::cleanup::CleanupMethods;
use trans::common::{self, Block, Result, NodeIdAndSpan, ExprId, CrateContext,
ExprOrMethodCall, FunctionContext, MethodCallKey};
use trans::consts;
use trans::datum::*;
use trans::debuginfo::DebugLoc;
use trans::declare;
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 trans::Disr;
use middle::ty::{self, Ty, TyCtxt, TypeFoldable};
use rustc_front::hir;
use syntax::abi::Abi;
use syntax::ast;
use syntax::codemap::DUMMY_SP;
use syntax::errors;
use syntax::ptr::P;
pub enum CalleeData<'tcx> {
/// Constructor for enum variant/tuple-like-struct.
NamedTupleConstructor(Disr),
/// Function pointer.
Fn(ValueRef),
Intrinsic(ast::NodeId, &'tcx subst::Substs<'tcx>),
/// Trait object found in the vtable at that index.
Virtual(usize)
}
pub struct Callee<'tcx> {
pub data: CalleeData<'tcx>,
pub ty: Ty<'tcx>
}
impl<'tcx> Callee<'tcx> {
/// Function pointer.
pub fn ptr(datum: Datum<'tcx, Rvalue>) -> Callee<'tcx> {
Callee {
data: Fn(datum.val),
ty: datum.ty
}
}
/// Trait or impl method call.
pub fn method_call<'blk>(bcx: Block<'blk, 'tcx>,
method_call: ty::MethodCall)
-> Callee<'tcx> {
let method = bcx.tcx().tables.borrow().method_map[&method_call];
Callee::method(bcx, method)
}
/// Trait or impl method.
pub fn method<'blk>(bcx: Block<'blk, 'tcx>,
method: ty::MethodCallee<'tcx>) -> Callee<'tcx> {
let substs = bcx.tcx().mk_substs(bcx.fcx.monomorphize(&method.substs));
let ty = bcx.fcx.monomorphize(&method.ty);
Callee::def(bcx.ccx(), method.def_id, substs, ty)
}
/// Function or method definition.
pub fn def<'a>(ccx: &CrateContext<'a, 'tcx>,
def_id: DefId,
substs: &'tcx subst::Substs<'tcx>,
ty: Ty<'tcx>)
-> Callee<'tcx> {
let tcx = ccx.tcx();
if substs.self_ty().is_some() {
// Only trait methods can have a Self parameter.
let method_item = tcx.impl_or_trait_item(def_id);
let trait_id = method_item.container().id();
let trait_ref = ty::Binder(substs.to_trait_ref(tcx, trait_id));
let vtbl = common::fulfill_obligation(ccx, DUMMY_SP, trait_ref);
return meth::callee_for_trait_impl(ccx, def_id, substs,
trait_id, ty, vtbl);
}
let maybe_node_id = inline::get_local_instance(ccx, def_id)
.and_then(|def_id| tcx.map.as_local_node_id(def_id));
let maybe_ast_node = maybe_node_id.and_then(|node_id| {
tcx.map.find(node_id)
});
match maybe_ast_node {
Some(hir_map::NodeStructCtor(_)) => {
return Callee {
data: NamedTupleConstructor(Disr(0)),
ty: ty
};
}
Some(hir_map::NodeVariant(_)) => {
let vinfo = common::inlined_variant_def(ccx, maybe_node_id.unwrap());
assert_eq!(vinfo.kind(), ty::VariantKind::Tuple);
return Callee {
data: NamedTupleConstructor(Disr::from(vinfo.disr_val)),
ty: ty
};
}
Some(hir_map::NodeForeignItem(fi)) => {
let abi = tcx.map.get_foreign_abi(fi.id);
if abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic {
return Callee {
data: Intrinsic(fi.id, substs),
ty: ty
};
}
}
_ => {}
}
Callee::ptr(trans_fn_ref_with_substs(ccx, def_id, Some(ty), substs))
}
/// 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 call<'a, 'blk>(self, bcx: Block<'blk, 'tcx>,
debug_loc: DebugLoc,
args: CallArgs<'a, 'tcx>,
dest: Option<expr::Dest>)
-> Result<'blk, 'tcx> {
trans_call_inner(bcx, debug_loc, self, args, dest)
}
/// Turn the callee into a function pointer.
pub fn reify<'a>(self, ccx: &CrateContext<'a, 'tcx>)
-> Datum<'tcx, Rvalue> {
match self.data {
Fn(llfn) => {
let fn_ptr_ty = match self.ty.sty {
ty::TyFnDef(_, _, f) => ccx.tcx().mk_ty(ty::TyFnPtr(f)),
_ => self.ty
};
immediate_rvalue(llfn, fn_ptr_ty)
}
Virtual(idx) => meth::trans_object_shim(ccx, self.ty, idx),
NamedTupleConstructor(_) => match self.ty.sty {
ty::TyFnDef(def_id, substs, _) => {
return trans_fn_ref_with_substs(ccx, def_id, Some(self.ty), substs);
}
_ => unreachable!("expected fn item type, found {}", self.ty)
},
Intrinsic(..) => unreachable!("intrinsic {} getting reified", self.ty)
}
}
}
/// 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: 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,
node,
substs);
let ref_ty = match node {
ExprId(0) => return trans_fn_ref_with_substs(ccx, def_id, None, substs),
ExprId(id) => ccx.tcx().node_id_to_type(id),
MethodCallKey(method_call) => {
ccx.tcx().tables.borrow().method_map[&method_call].ty
}
};
let ref_ty = monomorphize::apply_param_substs(ccx.tcx(),
param_substs,
&ref_ty);
trans_fn_ref_with_substs(ccx, def_id, Some(ref_ty), substs)
}
/// Translates an adapter that implements the `Fn` trait for a fn
/// pointer. This is basically the equivalent of something like:
///
/// ```
/// 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>,
closure_kind: ty::ClosureKind,
bare_fn_ty: Ty<'tcx>)
-> ValueRef
{
let _icx = push_ctxt("trans_fn_pointer_shim");
let tcx = ccx.tcx();
// Normalize the type for better caching.
let bare_fn_ty = tcx.erase_regions(&bare_fn_ty);
// If this is an impl of `Fn` or `FnMut` trait, the receiver is `&self`.
let is_by_ref = match closure_kind {
ty::ClosureKind::Fn | ty::ClosureKind::FnMut => true,
ty::ClosureKind::FnOnce => false,
};
let bare_fn_ty_maybe_ref = if is_by_ref {
tcx.mk_imm_ref(tcx.mk_region(ty::ReStatic), bare_fn_ty)
} else {
bare_fn_ty
};
// Check if we already trans'd this shim.
match ccx.fn_pointer_shims().borrow().get(&bare_fn_ty_maybe_ref) {
Some(&llval) => { return llval; }
None => { }
}
debug!("trans_fn_pointer_shim(bare_fn_ty={:?})",
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 sig = match bare_fn_ty.sty {
ty::TyFnDef(_, _,
&ty::BareFnTy { unsafety: hir::Unsafety::Normal,
abi: Abi::Rust,
ref sig }) |
ty::TyFnPtr(&ty::BareFnTy { unsafety: hir::Unsafety::Normal,
abi: Abi::Rust,
ref sig }) => sig,
_ => {
tcx.sess.bug(&format!("trans_fn_pointer_shim invoked on invalid type: {}",
bare_fn_ty));
}
};
let sig = tcx.erase_late_bound_regions(sig);
let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
let tuple_input_ty = tcx.mk_tup(sig.inputs.to_vec());
let tuple_fn_ty = tcx.mk_fn_ptr(ty::BareFnTy {
unsafety: hir::Unsafety::Normal,
abi: Abi::RustCall,
sig: ty::Binder(ty::FnSig {
inputs: vec![bare_fn_ty_maybe_ref,
tuple_input_ty],
output: sig.output,
variadic: false
})
});
debug!("tuple_fn_ty: {:?}", tuple_fn_ty);
//
let function_name = link::mangle_internal_name_by_type_and_seq(ccx, bare_fn_ty,
"fn_pointer_shim");
let llfn = declare::declare_internal_rust_fn(ccx, &function_name[..], tuple_fn_ty);
//
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);
let llargs = get_params(fcx.llfn);
let self_idx = fcx.arg_offset();
let llfnpointer = match bare_fn_ty.sty {
ty::TyFnDef(def_id, substs, _) => {
// Function definitions have to be turned into a pointer.
Callee::def(ccx, def_id, substs, bare_fn_ty).reify(ccx).val
}
// the first argument (`self`) will be ptr to the fn pointer
_ => if is_by_ref {
Load(bcx, llargs[self_idx])
} else {
llargs[self_idx]
}
};
assert!(!fcx.needs_ret_allocas);
let dest = fcx.llretslotptr.get().map(|_|
expr::SaveIn(fcx.get_ret_slot(bcx, sig.output, "ret_slot"))
);
let callee = Callee {
data: Fn(llfnpointer),
ty: bare_fn_ty
};
bcx = callee.call(bcx, DebugLoc::None, ArgVals(&llargs[(self_idx + 1)..]), dest).bcx;
finish_fn(&fcx, bcx, sig.output, DebugLoc::None);
ccx.fn_pointer_shims().borrow_mut().insert(bare_fn_ty_maybe_ref, 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.
/// - `ref_ty`: monotype of the reference to the fn/method, if applicable.
/// This parameter may be None; but, if so, the resulting value may not
/// have the right type, so it must be cast before being used.
/// - `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: DefId,
ref_ty: Option<Ty<'tcx>>,
substs: &'tcx 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={:?}, ref_ty={:?}, substs={:?})",
def_id, ref_ty, substs);
assert!(!substs.types.needs_infer());
assert!(!substs.types.has_escaping_regions());
// 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);
fn is_named_tuple_constructor(tcx: &TyCtxt, def_id: DefId) -> bool {
let node_id = match tcx.map.as_local_node_id(def_id) {
Some(n) => n,
None => { return false; }
};
let map_node = errors::expect(
&tcx.sess.diagnostic(),
tcx.map.find(node_id),
|| "local item should be in ast map".to_string());
match map_node {
hir_map::NodeVariant(v) => {
v.node.data.is_tuple()
}
hir_map::NodeStructCtor(_) => true,
_ => false
}
}
let must_monomorphise =
!substs.types.is_empty() || is_named_tuple_constructor(tcx, def_id);
debug!("trans_fn_ref_with_substs({:?}) must_monomorphise: {}",
def_id, must_monomorphise);
// Create a monomorphic version of generic functions
if must_monomorphise {
// Should be either intra-crate or inlined.
assert_eq!(def_id.krate, LOCAL_CRATE);
let substs = tcx.mk_substs(substs.clone().erase_regions());
let (mut val, fn_ty, must_cast) =
monomorphize::monomorphic_fn(ccx, def_id, substs);
let fn_ty = ref_ty.unwrap_or(fn_ty);
let fn_ptr_ty = match fn_ty.sty {
ty::TyFnDef(_, _, fty) => {
// Create a fn pointer with the substituted signature.
tcx.mk_ty(ty::TyFnPtr(fty))
}
_ => unreachable!("expected fn item type, found {}", fn_ty)
};
if must_cast && ref_ty.is_some() {
let llptrty = type_of::type_of(ccx, fn_ptr_ty);
if llptrty != common::val_ty(val) {
val = consts::ptrcast(val, llptrty);
}
}
return immediate_rvalue(val, fn_ptr_ty);
}
// Find the actual function pointer.
let local_node = ccx.tcx().map.as_local_node_id(def_id);
let mut datum = if let Some(node_id) = local_node {
// Type scheme of the function item (may have type params)
let fn_type_scheme = tcx.lookup_item_type(def_id);
let fn_type = match fn_type_scheme.ty.sty {
ty::TyFnDef(_, _, fty) => {
// Create a fn pointer with the normalized signature.
tcx.mk_fn_ptr(infer::normalize_associated_type(tcx, fty))
}
_ => unreachable!("expected fn item type, found {}",
fn_type_scheme.ty)
};
// Internal reference.
immediate_rvalue(get_item_val(ccx, node_id), fn_type)
} else {
// External reference.
get_extern_fn(ccx, def_id)
};
// 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 llptrty = type_of::type_of(ccx, datum.ty);
if common::val_ty(datum.val) != llptrty {
debug!("trans_fn_ref_with_substs(): casting pointer!");
datum.val = consts::ptrcast(datum.val, llptrty);
} else {
debug!("trans_fn_ref_with_substs(): not casting pointer!");
}
datum
}
// ______________________________________________________________________
// Translating calls
pub fn trans_lang_call<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
did: DefId,
args: &[ValueRef],
dest: Option<expr::Dest>,
debug_loc: DebugLoc)
-> Result<'blk, 'tcx> {
let datum = trans_fn_ref(bcx.ccx(), did, ExprId(0), bcx.fcx.param_substs);
Callee::ptr(datum).call(bcx, debug_loc, ArgVals(args), dest)
}
fn trans_call_inner<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
debug_loc: DebugLoc,
callee: Callee<'tcx>,
args: CallArgs<'a, 'tcx>,
dest: Option<expr::Dest>)
-> Result<'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 (abi, ret_ty) = match callee.ty.sty {
ty::TyFnDef(_, _, ref f) | ty::TyFnPtr(ref f) => {
let sig = bcx.tcx().erase_late_bound_regions(&f.sig);
let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
(f.abi, sig.output)
}
_ => panic!("expected fn item or ptr in Callee::call")
};
match callee.data {
Intrinsic(node, substs) => {
assert!(abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic);
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?")
}
};
let arg_cleanup_scope = fcx.push_custom_cleanup_scope();
return intrinsic::trans_intrinsic_call(bcx, node, callee.ty,
arg_cleanup_scope, args,
dest.unwrap(),
substs,
call_info);
}
NamedTupleConstructor(disr) => {
assert!(dest.is_some());
return base::trans_named_tuple_constructor(bcx,
callee.ty,
disr,
args,
dest.unwrap(),
debug_loc);
}
_ => {}
}
// Intrinsics should not become actual functions.
// We trans them in place in `trans_intrinsic_call`
assert!(abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic);
let is_rust_fn = abi == Abi::Rust || abi == Abi::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 => ccx.tcx().mk_nil()
};
if !is_rust_fn ||
type_of::return_uses_outptr(ccx, ret_ty) ||
bcx.fcx.type_needs_drop(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 {
let llresult = alloc_ty(bcx, ret_ty, "__llret");
call_lifetime_start(bcx, llresult);
Some(llresult)
}
} else {
None
}
}
});
let mut llresult = unsafe {
llvm::LLVMGetUndef(Type::nil(ccx).ptr_to().to_ref())
};
let arg_cleanup_scope = fcx.push_custom_cleanup_scope();
// 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(mut llretslot)) = (ret_ty, opt_llretslot) {
if type_of::return_uses_outptr(ccx, ret_ty) {
let llformal_ret_ty = type_of::type_of(ccx, ret_ty).ptr_to();
let llret_ty = common::val_ty(llretslot);
if llformal_ret_ty != llret_ty {
// this could happen due to e.g. subtyping
debug!("casting actual return type ({}) to match formal ({})",
bcx.llty_str(llret_ty), bcx.llty_str(llformal_ret_ty));
llretslot = PointerCast(bcx, llretslot, llformal_ret_ty);
}
llargs.push(llretslot);
}
}
let arg_start = llargs.len();
// Push the arguments.
bcx = trans_args(bcx,
args,
callee.ty,
&mut llargs,
cleanup::CustomScope(arg_cleanup_scope),
abi);
fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
let datum = match callee.data {
Fn(f) => immediate_rvalue(f, callee.ty),
Virtual(idx) => {
// The data and vtable pointers were split by trans_arg_datum.
let vtable = llargs.remove(arg_start + 1);
meth::get_virtual_method(bcx, vtable, idx, callee.ty)
}
_ => unreachable!()
};
// Invoke the actual rust fn and update bcx/llresult.
let (llret, b) = base::invoke(bcx,
datum.val,
&llargs[..],
datum.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 (llfn, arg_tys) = match (callee.data, &args) {
(Fn(f), &ArgExprs(a)) => {
(f, a.iter().map(|x| common::expr_ty_adjusted(bcx, &x)).collect())
}
_ => panic!("expected fn ptr and arg exprs.")
};
bcx = trans_args(bcx,
args,
callee.ty,
&mut llargs,
cleanup::CustomScope(arg_cleanup_scope),
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<hir::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, Option(rhs))`.
/// `lhs` is the left-hand-side and `rhs` is the datum
/// of the right-hand-side argument (if any).
ArgOverloadedOp(Datum<'tcx, Expr>, Option<Datum<'tcx, Expr>>),
/// Supply value of arguments as a list of expressions that must be
/// translated, for overloaded call operators.
ArgOverloadedCall(Vec<&'a hir::Expr>),
}
fn trans_args_under_call_abi<'blk, 'tcx>(
mut bcx: Block<'blk, 'tcx>,
arg_exprs: &[P<hir::Expr>],
fn_ty: Ty<'tcx>,
llargs: &mut Vec<ValueRef>,
arg_cleanup_scope: cleanup::ScopeId)
-> Block<'blk, 'tcx>
{
let sig = bcx.tcx().erase_late_bound_regions(&fn_ty.fn_sig());
let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
let args = sig.inputs;
// Translate the `self` argument first.
let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &arg_exprs[0]));
bcx = trans_arg_datum(bcx,
args[0],
arg_datum,
arg_cleanup_scope,
llargs);
// 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::TyTuple(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, field_type) in field_types.iter().enumerate() {
let arg_datum = tuple_lvalue_datum.get_element(
bcx,
field_type,
|srcval| {
adt::trans_field_ptr(bcx, repr_ptr, srcval, Disr(0), i)
}).to_expr_datum();
bcx = trans_arg_datum(bcx,
field_type,
arg_datum,
arg_cleanup_scope,
llargs);
}
}
_ => {
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<&hir::Expr>,
fn_ty: Ty<'tcx>,
llargs: &mut Vec<ValueRef>,
arg_cleanup_scope: cleanup::ScopeId)
-> Block<'blk, 'tcx> {
// Translate the `self` argument first.
let sig = bcx.tcx().erase_late_bound_regions(&fn_ty.fn_sig());
let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
let arg_tys = sig.inputs;
let arg_datum = unpack_datum!(bcx, expr::trans(bcx, arg_exprs[0]));
bcx = trans_arg_datum(bcx,
arg_tys[0],
arg_datum,
arg_cleanup_scope,
llargs);
// Now untuple the rest of the arguments.
let tuple_type = arg_tys[1];
match tuple_type.sty {
ty::TyTuple(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]));
bcx = trans_arg_datum(bcx,
field_type,
arg_datum,
arg_cleanup_scope,
llargs);
}
}
_ => {
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,
abi: Abi)
-> Block<'blk, 'tcx> {
debug!("trans_args(abi={})", abi);
let _icx = push_ctxt("trans_args");
let sig = cx.tcx().erase_late_bound_regions(&fn_ty.fn_sig());
let sig = infer::normalize_associated_type(cx.tcx(), &sig);
let arg_tys = sig.inputs;
let variadic = sig.variadic;
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 == Abi::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)
}
let num_formal_args = arg_tys.len();
for (i, arg_expr) in arg_exprs.iter().enumerate() {
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));
bcx = trans_arg_datum(bcx, arg_ty, arg_datum,
arg_cleanup_scope,
llargs);
}
}
ArgOverloadedCall(arg_exprs) => {
return trans_overloaded_call_args(cx,
arg_exprs,
fn_ty,
llargs,
arg_cleanup_scope)
}
ArgOverloadedOp(lhs, rhs) => {
assert!(!variadic);
bcx = trans_arg_datum(bcx, arg_tys[0], lhs,
arg_cleanup_scope,
llargs);
if let Some(rhs) = rhs {
assert_eq!(arg_tys.len(), 2);
bcx = trans_arg_datum(bcx, arg_tys[1], rhs,
arg_cleanup_scope,
llargs);
} else {
assert_eq!(arg_tys.len(), 1);
}
}
ArgVals(vs) => {
llargs.extend_from_slice(vs);
}
}
bcx
}
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,
llargs: &mut Vec<ValueRef>)
-> Block<'blk, 'tcx> {
let _icx = push_ctxt("trans_arg_datum");
let mut bcx = bcx;
let ccx = bcx.ccx();
debug!("trans_arg_datum({:?})",
formal_arg_ty);
let arg_datum_ty = arg_datum.ty;
debug!(" arg datum: {}", arg_datum.to_string(bcx.ccx()));
let mut val = if common::type_is_fat_ptr(bcx.tcx(), arg_datum_ty) &&
!bcx.fcx.type_needs_drop(arg_datum_ty) {
arg_datum.val
} else {
// 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.
arg_datum.add_clean(bcx.fcx, arg_cleanup_scope)
};
if type_of::arg_is_indirect(ccx, formal_arg_ty) && 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: {:?}; {:?}", arg_datum_ty,
formal_arg_ty);
val = PointerCast(bcx, val, llformal_arg_ty);
}
debug!("--- trans_arg_datum passing {}", bcx.val_to_string(val));
if common::type_is_fat_ptr(bcx.tcx(), formal_arg_ty) {
llargs.push(Load(bcx, expr::get_dataptr(bcx, val)));
llargs.push(Load(bcx, expr::get_meta(bcx, val)));
} else {
llargs.push(val);
}
bcx
}