1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Handles translation of callees as well as other call-related
12 //! things. Callees are a superset of normal rust values and sometimes
13 //! have different representations. In particular, top-level fn items
14 //! and methods are represented as just a fn ptr and not a full
17 pub use self::CalleeData::*;
18 pub use self::CallArgs::*;
20 use arena::TypedArena;
22 use llvm::{self, ValueRef, get_params};
23 use middle::cstore::LOCAL_CRATE;
24 use middle::def_id::DefId;
27 use middle::subst::{Substs};
29 use rustc::front::map as hir_map;
30 use trans::abi::{Abi, FnType};
32 use trans::attributes;
37 use trans::cleanup::CleanupMethods;
39 use trans::common::{self, Block, Result, CrateContext, FunctionContext};
40 use trans::common::{C_uint, C_undef};
43 use trans::debuginfo::DebugLoc;
49 use trans::machine::{llalign_of_min, llsize_of_store};
51 use trans::monomorphize::{self, Instance};
52 use trans::type_::Type;
54 use trans::value::Value;
56 use middle::ty::{self, Ty, TyCtxt, TypeFoldable};
59 use syntax::codemap::DUMMY_SP;
67 /// Constructor for enum variant/tuple-like-struct.
68 NamedTupleConstructor(Disr),
75 /// Trait object found in the vtable at that index.
80 pub struct Callee<'tcx> {
85 impl<'tcx> Callee<'tcx> {
87 pub fn ptr(datum: Datum<'tcx, Rvalue>) -> Callee<'tcx> {
94 /// Trait or impl method call.
95 pub fn method_call<'blk>(bcx: Block<'blk, 'tcx>,
96 method_call: ty::MethodCall)
98 let method = bcx.tcx().tables.borrow().method_map[&method_call];
99 Callee::method(bcx, method)
102 /// Trait or impl method.
103 pub fn method<'blk>(bcx: Block<'blk, 'tcx>,
104 method: ty::MethodCallee<'tcx>) -> Callee<'tcx> {
105 let substs = bcx.tcx().mk_substs(bcx.fcx.monomorphize(&method.substs));
106 Callee::def(bcx.ccx(), method.def_id, substs)
109 /// Function or method definition.
110 pub fn def<'a>(ccx: &CrateContext<'a, 'tcx>,
112 substs: &'tcx subst::Substs<'tcx>)
116 if substs.self_ty().is_some() {
117 // Only trait methods can have a Self parameter.
118 return Callee::trait_method(ccx, def_id, substs);
121 let maybe_node_id = inline::get_local_instance(ccx, def_id)
122 .and_then(|def_id| tcx.map.as_local_node_id(def_id));
123 let maybe_ast_node = maybe_node_id.and_then(|node_id| {
124 tcx.map.find(node_id)
127 let data = match maybe_ast_node {
128 Some(hir_map::NodeStructCtor(_)) => {
129 NamedTupleConstructor(Disr(0))
131 Some(hir_map::NodeVariant(_)) => {
132 let vinfo = common::inlined_variant_def(ccx, maybe_node_id.unwrap());
133 NamedTupleConstructor(Disr::from(vinfo.disr_val))
135 Some(hir_map::NodeForeignItem(fi)) if {
136 let abi = tcx.map.get_foreign_abi(fi.id);
137 abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic
140 _ => return Callee::ptr(get_fn(ccx, def_id, substs))
145 ty: def_ty(tcx, def_id, substs)
149 /// Trait method, which has to be resolved to an impl method.
150 pub fn trait_method<'a>(ccx: &CrateContext<'a, 'tcx>,
152 substs: &'tcx subst::Substs<'tcx>)
156 let method_item = tcx.impl_or_trait_item(def_id);
157 let trait_id = method_item.container().id();
158 let trait_ref = ty::Binder(substs.to_trait_ref(tcx, trait_id));
159 match common::fulfill_obligation(ccx, DUMMY_SP, trait_ref) {
160 traits::VtableImpl(vtable_impl) => {
161 let impl_did = vtable_impl.impl_def_id;
162 let mname = tcx.item_name(def_id);
163 // create a concatenated set of substitutions which includes
164 // those from the impl and those from the method:
165 let impl_substs = vtable_impl.substs.with_method_from(&substs);
166 let substs = tcx.mk_substs(impl_substs);
167 let mth = meth::get_impl_method(tcx, impl_did, substs, mname);
169 // Translate the function, bypassing Callee::def.
170 // That is because default methods have the same ID as the
171 // trait method used to look up the impl method that ended
172 // up here, so calling Callee::def would infinitely recurse.
173 Callee::ptr(get_fn(ccx, mth.method.def_id, mth.substs))
175 traits::VtableClosure(vtable_closure) => {
176 // The substitutions should have no type parameters remaining
177 // after passing through fulfill_obligation
178 let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_id).unwrap();
179 let llfn = closure::trans_closure_method(ccx,
180 vtable_closure.closure_def_id,
181 vtable_closure.substs,
184 let method_ty = def_ty(tcx, def_id, substs);
185 let fn_ptr_ty = match method_ty.sty {
186 ty::TyFnDef(_, _, fty) => tcx.mk_ty(ty::TyFnPtr(fty)),
187 _ => unreachable!("expected fn item type, found {}",
190 Callee::ptr(immediate_rvalue(llfn, fn_ptr_ty))
192 traits::VtableFnPointer(fn_ty) => {
193 let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_id).unwrap();
194 let llfn = trans_fn_pointer_shim(ccx, trait_closure_kind, fn_ty);
196 let method_ty = def_ty(tcx, def_id, substs);
197 let fn_ptr_ty = match method_ty.sty {
198 ty::TyFnDef(_, _, fty) => tcx.mk_ty(ty::TyFnPtr(fty)),
199 _ => unreachable!("expected fn item type, found {}",
202 Callee::ptr(immediate_rvalue(llfn, fn_ptr_ty))
204 traits::VtableObject(ref data) => {
206 data: Virtual(traits::get_vtable_index_of_object_method(
208 ty: def_ty(tcx, def_id, substs)
212 unreachable!("resolved vtable bad vtable {:?} in trans", vtable);
217 /// Get the abi::FnType for a direct call. Mainly deals with the fact
218 /// that a Virtual call doesn't take the vtable, like its shim does.
219 /// The extra argument types are for variadic (extern "C") functions.
220 pub fn direct_fn_type<'a>(&self, ccx: &CrateContext<'a, 'tcx>,
221 extra_args: &[Ty<'tcx>]) -> FnType {
222 let abi = self.ty.fn_abi();
223 let sig = ccx.tcx().erase_late_bound_regions(self.ty.fn_sig());
224 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
225 let mut fn_ty = FnType::unadjusted(ccx, abi, &sig, extra_args);
226 if let Virtual(_) = self.data {
227 // Don't pass the vtable, it's not an argument of the virtual fn.
228 fn_ty.args[1].ignore();
230 fn_ty.adjust_for_abi(ccx, abi, &sig);
234 /// This behemoth of a function translates function calls. Unfortunately, in
235 /// order to generate more efficient LLVM output at -O0, it has quite a complex
236 /// signature (refactoring this into two functions seems like a good idea).
238 /// In particular, for lang items, it is invoked with a dest of None, and in
239 /// that case the return value contains the result of the fn. The lang item must
240 /// not return a structural type or else all heck breaks loose.
242 /// For non-lang items, `dest` is always Some, and hence the result is written
243 /// into memory somewhere. Nonetheless we return the actual return value of the
245 pub fn call<'a, 'blk>(self, bcx: Block<'blk, 'tcx>,
247 args: CallArgs<'a, 'tcx>,
248 dest: Option<expr::Dest>)
249 -> Result<'blk, 'tcx> {
250 trans_call_inner(bcx, debug_loc, self, args, dest)
253 /// Turn the callee into a function pointer.
254 pub fn reify<'a>(self, ccx: &CrateContext<'a, 'tcx>)
255 -> Datum<'tcx, Rvalue> {
256 let fn_ptr_ty = match self.ty.sty {
257 ty::TyFnDef(_, _, f) => ccx.tcx().mk_ty(ty::TyFnPtr(f)),
262 immediate_rvalue(llfn, fn_ptr_ty)
265 let llfn = meth::trans_object_shim(ccx, self.ty, idx);
266 immediate_rvalue(llfn, fn_ptr_ty)
268 NamedTupleConstructor(_) => match self.ty.sty {
269 ty::TyFnDef(def_id, substs, _) => {
270 return get_fn(ccx, def_id, substs);
272 _ => unreachable!("expected fn item type, found {}", self.ty)
274 Intrinsic => unreachable!("intrinsic {} getting reified", self.ty)
279 /// Given a DefId and some Substs, produces the monomorphic item type.
280 fn def_ty<'tcx>(tcx: &TyCtxt<'tcx>,
282 substs: &'tcx subst::Substs<'tcx>)
284 let ty = tcx.lookup_item_type(def_id).ty;
285 monomorphize::apply_param_substs(tcx, substs, &ty)
288 /// Translates an adapter that implements the `Fn` trait for a fn
289 /// pointer. This is basically the equivalent of something like:
292 /// impl<'a> Fn(&'a int) -> &'a int for fn(&int) -> &int {
293 /// extern "rust-abi" fn call(&self, args: (&'a int,)) -> &'a int {
299 /// but for the bare function type given.
300 pub fn trans_fn_pointer_shim<'a, 'tcx>(
301 ccx: &'a CrateContext<'a, 'tcx>,
302 closure_kind: ty::ClosureKind,
303 bare_fn_ty: Ty<'tcx>)
306 let _icx = push_ctxt("trans_fn_pointer_shim");
309 // Normalize the type for better caching.
310 let bare_fn_ty = tcx.erase_regions(&bare_fn_ty);
312 // If this is an impl of `Fn` or `FnMut` trait, the receiver is `&self`.
313 let is_by_ref = match closure_kind {
314 ty::ClosureKind::Fn | ty::ClosureKind::FnMut => true,
315 ty::ClosureKind::FnOnce => false,
318 let llfnpointer = match bare_fn_ty.sty {
319 ty::TyFnDef(def_id, substs, _) => {
320 // Function definitions have to be turned into a pointer.
321 let llfn = Callee::def(ccx, def_id, substs).reify(ccx).val;
323 // A by-value fn item is ignored, so the shim has
324 // the same signature as the original function.
332 let bare_fn_ty_maybe_ref = if is_by_ref {
333 tcx.mk_imm_ref(tcx.mk_region(ty::ReStatic), bare_fn_ty)
338 // Check if we already trans'd this shim.
339 match ccx.fn_pointer_shims().borrow().get(&bare_fn_ty_maybe_ref) {
340 Some(&llval) => { return llval; }
344 debug!("trans_fn_pointer_shim(bare_fn_ty={:?})",
347 // Construct the "tuply" version of `bare_fn_ty`. It takes two arguments: `self`,
348 // which is the fn pointer, and `args`, which is the arguments tuple.
349 let sig = match bare_fn_ty.sty {
351 &ty::BareFnTy { unsafety: hir::Unsafety::Normal,
354 ty::TyFnPtr(&ty::BareFnTy { unsafety: hir::Unsafety::Normal,
359 tcx.sess.bug(&format!("trans_fn_pointer_shim invoked on invalid type: {}",
363 let sig = tcx.erase_late_bound_regions(sig);
364 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
365 let tuple_input_ty = tcx.mk_tup(sig.inputs.to_vec());
366 let sig = ty::FnSig {
367 inputs: vec![bare_fn_ty_maybe_ref,
372 let fn_ty = FnType::new(ccx, Abi::RustCall, &sig, &[]);
373 let tuple_fn_ty = tcx.mk_fn_ptr(ty::BareFnTy {
374 unsafety: hir::Unsafety::Normal,
378 debug!("tuple_fn_ty: {:?}", tuple_fn_ty);
381 let function_name = link::mangle_internal_name_by_type_and_seq(ccx, bare_fn_ty,
383 let llfn = declare::define_internal_fn(ccx, &function_name, tuple_fn_ty);
386 let empty_substs = tcx.mk_substs(Substs::trans_empty());
387 let (block_arena, fcx): (TypedArena<_>, FunctionContext);
388 block_arena = TypedArena::new();
389 fcx = FunctionContext::new(ccx, llfn, fn_ty, None, empty_substs, &block_arena);
390 let mut bcx = fcx.init(false, None);
392 let llargs = get_params(fcx.llfn);
394 let self_idx = fcx.fn_ty.ret.is_indirect() as usize;
395 let llfnpointer = llfnpointer.unwrap_or_else(|| {
396 // the first argument (`self`) will be ptr to the fn pointer
398 Load(bcx, llargs[self_idx])
404 assert!(!fcx.needs_ret_allocas);
406 let dest = fcx.llretslotptr.get().map(|_|
407 expr::SaveIn(fcx.get_ret_slot(bcx, "ret_slot"))
410 let callee = Callee {
411 data: Fn(llfnpointer),
414 bcx = callee.call(bcx, DebugLoc::None, ArgVals(&llargs[(self_idx + 1)..]), dest).bcx;
416 fcx.finish(bcx, DebugLoc::None);
418 ccx.fn_pointer_shims().borrow_mut().insert(bare_fn_ty_maybe_ref, llfn);
423 /// Translates a reference to a fn/method item, monomorphizing and
424 /// inlining as it goes.
428 /// - `ccx`: the crate context
429 /// - `def_id`: def id of the fn or method item being referenced
430 /// - `substs`: values for each of the fn/method's parameters
431 fn get_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
433 substs: &'tcx subst::Substs<'tcx>)
434 -> Datum<'tcx, Rvalue> {
437 debug!("get_fn(def_id={:?}, substs={:?})", def_id, substs);
439 assert!(!substs.types.needs_infer());
440 assert!(!substs.types.has_escaping_regions());
442 // Check whether this fn has an inlined copy and, if so, redirect
443 // def_id to the local id of the inlined copy.
444 let def_id = inline::maybe_instantiate_inline(ccx, def_id);
446 fn is_named_tuple_constructor(tcx: &TyCtxt, def_id: DefId) -> bool {
447 let node_id = match tcx.map.as_local_node_id(def_id) {
449 None => { return false; }
451 let map_node = errors::expect(
452 &tcx.sess.diagnostic(),
453 tcx.map.find(node_id),
454 || "local item should be in ast map".to_string());
457 hir_map::NodeVariant(v) => {
458 v.node.data.is_tuple()
460 hir_map::NodeStructCtor(_) => true,
464 let must_monomorphise =
465 !substs.types.is_empty() || is_named_tuple_constructor(tcx, def_id);
467 debug!("get_fn({:?}) must_monomorphise: {}",
468 def_id, must_monomorphise);
470 // Create a monomorphic version of generic functions
471 if must_monomorphise {
472 // Should be either intra-crate or inlined.
473 assert_eq!(def_id.krate, LOCAL_CRATE);
475 let substs = tcx.mk_substs(substs.clone().erase_regions());
476 let (val, fn_ty) = monomorphize::monomorphic_fn(ccx, def_id, substs);
477 let fn_ptr_ty = match fn_ty.sty {
478 ty::TyFnDef(_, _, fty) => {
479 // Create a fn pointer with the substituted signature.
480 tcx.mk_ty(ty::TyFnPtr(fty))
482 _ => unreachable!("expected fn item type, found {}", fn_ty)
484 assert_eq!(type_of::type_of(ccx, fn_ptr_ty), common::val_ty(val));
485 return immediate_rvalue(val, fn_ptr_ty);
488 // Find the actual function pointer.
489 let ty = ccx.tcx().lookup_item_type(def_id).ty;
490 let fn_ptr_ty = match ty.sty {
491 ty::TyFnDef(_, _, fty) => {
492 // Create a fn pointer with the normalized signature.
493 tcx.mk_fn_ptr(infer::normalize_associated_type(tcx, fty))
495 _ => unreachable!("expected fn item type, found {}", ty)
498 let instance = Instance::mono(ccx.tcx(), def_id);
499 if let Some(&llfn) = ccx.instances().borrow().get(&instance) {
500 return immediate_rvalue(llfn, fn_ptr_ty);
504 let local_id = ccx.tcx().map.as_local_node_id(def_id);
505 let maybe_node = local_id.and_then(|id| tcx.map.find(id));
506 let (sym, attrs, local_item) = match maybe_node {
507 Some(hir_map::NodeItem(&hir::Item {
508 ref attrs, id, span, node: hir::ItemFn(..), ..
510 Some(hir_map::NodeTraitItem(&hir::TraitItem {
511 ref attrs, id, span, node: hir::MethodTraitItem(_, Some(_)), ..
513 Some(hir_map::NodeImplItem(&hir::ImplItem {
514 ref attrs, id, span, node: hir::ImplItemKind::Method(..), ..
516 let sym = exported_name(ccx, id, ty, attrs);
518 if declare::get_defined_value(ccx, &sym).is_some() {
519 ccx.sess().span_fatal(span,
520 &format!("symbol `{}` is already defined", sym));
523 (sym, &attrs[..], Some(id))
526 Some(hir_map::NodeForeignItem(&hir::ForeignItem {
527 ref attrs, name, node: hir::ForeignItemFn(..), ..
529 (imported_name(name, attrs).to_string(), &attrs[..], None)
533 attrs = ccx.sess().cstore.item_attrs(def_id);
534 (ccx.sess().cstore.item_symbol(def_id), &attrs[..], None)
538 ccx.sess().bug(&format!("get_fn: unexpected variant: {:?}", variant))
542 let llfn = declare::declare_fn(ccx, &sym, ty);
543 attributes::from_fn_attrs(ccx, attrs, llfn);
544 if let Some(id) = local_item {
545 // FIXME(eddyb) Doubt all extern fn should allow unwinding.
546 attributes::unwind(llfn, true);
547 ccx.item_symbols().borrow_mut().insert(id, sym);
550 // This is subtle and surprising, but sometimes we have to bitcast
551 // the resulting fn pointer. The reason has to do with external
552 // functions. If you have two crates that both bind the same C
553 // library, they may not use precisely the same types: for
554 // example, they will probably each declare their own structs,
555 // which are distinct types from LLVM's point of view (nominal
558 // Now, if those two crates are linked into an application, and
559 // they contain inlined code, you can wind up with a situation
560 // where both of those functions wind up being loaded into this
561 // application simultaneously. In that case, the same function
562 // (from LLVM's point of view) requires two types. But of course
563 // LLVM won't allow one function to have two types.
565 // What we currently do, therefore, is declare the function with
566 // one of the two types (whichever happens to come first) and then
567 // bitcast as needed when the function is referenced to make sure
568 // it has the type we expect.
570 // This can occur on either a crate-local or crate-external
571 // reference. It also occurs when testing libcore and in some
572 // other weird situations. Annoying.
573 let llptrty = type_of::type_of(ccx, fn_ptr_ty);
574 let llfn = if common::val_ty(llfn) != llptrty {
575 debug!("get_fn: casting {:?} to {:?}", llfn, llptrty);
576 consts::ptrcast(llfn, llptrty)
578 debug!("get_fn: not casting pointer!");
582 ccx.instances().borrow_mut().insert(instance, llfn);
584 immediate_rvalue(llfn, fn_ptr_ty)
587 // ______________________________________________________________________
590 fn trans_call_inner<'a, 'blk, 'tcx>(mut bcx: Block<'blk, 'tcx>,
592 callee: Callee<'tcx>,
593 args: CallArgs<'a, 'tcx>,
594 dest: Option<expr::Dest>)
595 -> Result<'blk, 'tcx> {
596 // Introduce a temporary cleanup scope that will contain cleanups
597 // for the arguments while they are being evaluated. The purpose
598 // this cleanup is to ensure that, should a panic occur while
599 // evaluating argument N, the values for arguments 0...N-1 are all
600 // cleaned up. If no panic occurs, the values are handed off to
601 // the callee, and hence none of the cleanups in this temporary
602 // scope will ever execute.
606 let abi = callee.ty.fn_abi();
607 let sig = callee.ty.fn_sig();
608 let output = bcx.tcx().erase_late_bound_regions(&sig.output());
609 let output = infer::normalize_associated_type(bcx.tcx(), &output);
611 let extra_args = match args {
612 ArgExprs(args) if abi != Abi::RustCall => {
613 args[sig.0.inputs.len()..].iter().map(|expr| {
614 common::expr_ty_adjusted(bcx, expr)
619 let fn_ty = callee.direct_fn_type(ccx, &extra_args);
621 let mut callee = match callee.data {
623 assert!(abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic);
624 assert!(dest.is_some());
626 return intrinsic::trans_intrinsic_call(bcx, callee.ty, &fn_ty,
630 NamedTupleConstructor(disr) => {
631 assert!(dest.is_some());
633 return base::trans_named_tuple_constructor(bcx,
643 // Generate a location to store the result. If the user does
644 // not care about the result, just make a stack slot.
645 let opt_llretslot = dest.and_then(|dest| match dest {
646 expr::SaveIn(dst) => Some(dst),
648 let needs_drop = || match output {
649 ty::FnConverging(ret_ty) => bcx.fcx.type_needs_drop(ret_ty),
650 ty::FnDiverging => false
652 if fn_ty.ret.is_indirect() || fn_ty.ret.cast.is_some() || needs_drop() {
653 // Push the out-pointer if we use an out-pointer for this
654 // return type, otherwise push "undef".
655 if fn_ty.ret.is_ignore() {
656 Some(C_undef(fn_ty.ret.original_ty.ptr_to()))
658 let llresult = alloca(bcx, fn_ty.ret.original_ty, "__llret");
659 call_lifetime_start(bcx, llresult);
668 // If there no destination, return must be direct, with no cast.
669 if opt_llretslot.is_none() {
670 assert!(!fn_ty.ret.is_indirect() && fn_ty.ret.cast.is_none());
673 let mut llargs = Vec::new();
675 if fn_ty.ret.is_indirect() {
676 let mut llretslot = opt_llretslot.unwrap();
677 if let Some(ty) = fn_ty.ret.cast {
678 llretslot = PointerCast(bcx, llretslot, ty.ptr_to());
680 llargs.push(llretslot);
683 let arg_cleanup_scope = fcx.push_custom_cleanup_scope();
684 bcx = trans_args(bcx, abi, &fn_ty, &mut callee, args, &mut llargs,
685 cleanup::CustomScope(arg_cleanup_scope));
686 fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
688 let llfn = match callee {
690 _ => unreachable!("expected fn pointer callee, found {:?}", callee)
693 let (llret, mut bcx) = base::invoke(bcx, llfn, &llargs, debug_loc);
694 if !bcx.unreachable.get() {
695 fn_ty.apply_attrs_callsite(llret);
698 // If the function we just called does not use an outpointer,
699 // store the result into the rust outpointer. Cast the outpointer
700 // type to match because some ABIs will use a different type than
701 // the Rust type. e.g., a {u32,u32} struct could be returned as
703 if !fn_ty.ret.is_ignore() && !fn_ty.ret.is_indirect() {
704 if let Some(llforeign_ret_ty) = fn_ty.ret.cast {
705 let llrust_ret_ty = fn_ty.ret.original_ty;
706 let llretslot = opt_llretslot.unwrap();
708 // The actual return type is a struct, but the ABI
709 // adaptation code has cast it into some scalar type. The
710 // code that follows is the only reliable way I have
711 // found to do a transform like i64 -> {i32,i32}.
712 // Basically we dump the data onto the stack then memcpy it.
714 // Other approaches I tried:
715 // - Casting rust ret pointer to the foreign type and using Store
716 // is (a) unsafe if size of foreign type > size of rust type and
717 // (b) runs afoul of strict aliasing rules, yielding invalid
718 // assembly under -O (specifically, the store gets removed).
719 // - Truncating foreign type to correct integral type and then
720 // bitcasting to the struct type yields invalid cast errors.
721 let llscratch = base::alloca(bcx, llforeign_ret_ty, "__cast");
722 base::call_lifetime_start(bcx, llscratch);
723 Store(bcx, llret, llscratch);
724 let llscratch_i8 = PointerCast(bcx, llscratch, Type::i8(ccx).ptr_to());
725 let llretptr_i8 = PointerCast(bcx, llretslot, Type::i8(ccx).ptr_to());
726 let llrust_size = llsize_of_store(ccx, llrust_ret_ty);
727 let llforeign_align = llalign_of_min(ccx, llforeign_ret_ty);
728 let llrust_align = llalign_of_min(ccx, llrust_ret_ty);
729 let llalign = cmp::min(llforeign_align, llrust_align);
730 debug!("llrust_size={}", llrust_size);
732 if !bcx.unreachable.get() {
733 base::call_memcpy(&B(bcx), llretptr_i8, llscratch_i8,
734 C_uint(ccx, llrust_size), llalign as u32);
736 base::call_lifetime_end(bcx, llscratch);
737 } else if let Some(llretslot) = opt_llretslot {
738 base::store_ty(bcx, llret, llretslot, output.unwrap());
742 fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_cleanup_scope);
744 // If the caller doesn't care about the result of this fn call,
745 // drop the temporary slot we made.
746 match (dest, opt_llretslot, output) {
747 (Some(expr::Ignore), Some(llretslot), ty::FnConverging(ret_ty)) => {
748 // drop the value if it is not being saved.
749 bcx = glue::drop_ty(bcx, llretslot, ret_ty, debug_loc);
750 call_lifetime_end(bcx, llretslot);
755 if output == ty::FnDiverging {
759 Result::new(bcx, llret)
762 pub enum CallArgs<'a, 'tcx> {
763 /// Supply value of arguments as a list of expressions that must be
764 /// translated. This is used in the common case of `foo(bar, qux)`.
765 ArgExprs(&'a [P<hir::Expr>]),
767 /// Supply value of arguments as a list of LLVM value refs; frequently
768 /// used with lang items and so forth, when the argument is an internal
770 ArgVals(&'a [ValueRef]),
772 /// For overloaded operators: `(lhs, Option(rhs))`.
773 /// `lhs` is the left-hand-side and `rhs` is the datum
774 /// of the right-hand-side argument (if any).
775 ArgOverloadedOp(Datum<'tcx, Expr>, Option<Datum<'tcx, Expr>>),
777 /// Supply value of arguments as a list of expressions that must be
778 /// translated, for overloaded call operators.
779 ArgOverloadedCall(Vec<&'a hir::Expr>),
782 fn trans_args_under_call_abi<'blk, 'tcx>(
783 mut bcx: Block<'blk, 'tcx>,
784 arg_exprs: &[P<hir::Expr>],
785 callee: &mut CalleeData,
787 llargs: &mut Vec<ValueRef>,
788 arg_cleanup_scope: cleanup::ScopeId)
793 // Translate the `self` argument first.
794 let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &arg_exprs[0]));
795 bcx = trans_arg_datum(bcx,
797 callee, fn_ty, &mut arg_idx,
801 // Now untuple the rest of the arguments.
802 let tuple_expr = &arg_exprs[1];
803 let tuple_type = common::node_id_type(bcx, tuple_expr.id);
805 match tuple_type.sty {
806 ty::TyTuple(ref field_types) => {
807 let tuple_datum = unpack_datum!(bcx,
808 expr::trans(bcx, &tuple_expr));
809 let tuple_lvalue_datum =
811 tuple_datum.to_lvalue_datum(bcx,
814 let repr = adt::represent_type(bcx.ccx(), tuple_type);
815 let repr_ptr = &repr;
816 for (i, field_type) in field_types.iter().enumerate() {
817 let arg_datum = tuple_lvalue_datum.get_element(
821 adt::trans_field_ptr(bcx, repr_ptr, srcval, Disr(0), i)
823 bcx = trans_arg_datum(bcx,
825 callee, fn_ty, &mut arg_idx,
831 bcx.sess().span_bug(tuple_expr.span,
832 "argument to `.call()` wasn't a tuple?!")
839 pub fn trans_args<'a, 'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
842 callee: &mut CalleeData,
843 args: CallArgs<'a, 'tcx>,
844 llargs: &mut Vec<ValueRef>,
845 arg_cleanup_scope: cleanup::ScopeId)
846 -> Block<'blk, 'tcx> {
847 debug!("trans_args(abi={})", abi);
849 let _icx = push_ctxt("trans_args");
854 // First we figure out the caller's view of the types of the arguments.
855 // This will be needed if this is a generic call, because the callee has
856 // to cast her view of the arguments to the caller's view.
858 ArgExprs(arg_exprs) => {
859 if abi == Abi::RustCall {
860 // This is only used for direct calls to the `call`,
861 // `call_mut` or `call_once` functions.
862 return trans_args_under_call_abi(bcx,
863 arg_exprs, callee, fn_ty,
868 for arg_expr in arg_exprs {
869 let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &arg_expr));
870 bcx = trans_arg_datum(bcx,
872 callee, fn_ty, &mut arg_idx,
877 ArgOverloadedCall(arg_exprs) => {
878 for expr in arg_exprs {
880 unpack_datum!(bcx, expr::trans(bcx, expr));
881 bcx = trans_arg_datum(bcx,
883 callee, fn_ty, &mut arg_idx,
888 ArgOverloadedOp(lhs, rhs) => {
889 bcx = trans_arg_datum(bcx, lhs,
890 callee, fn_ty, &mut arg_idx,
894 if let Some(rhs) = rhs {
895 bcx = trans_arg_datum(bcx, rhs,
896 callee, fn_ty, &mut arg_idx,
906 let fn_ptr = meth::get_virtual_method(bcx, vs[1], idx);
907 let llty = fn_ty.llvm_type(bcx.ccx()).ptr_to();
908 *callee = Fn(PointerCast(bcx, fn_ptr, llty));
909 llargs.extend_from_slice(&vs[2..]);
911 _ => llargs.extend_from_slice(vs)
919 fn trans_arg_datum<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
920 arg_datum: Datum<'tcx, Expr>,
921 callee: &mut CalleeData,
923 next_idx: &mut usize,
924 arg_cleanup_scope: cleanup::ScopeId,
925 llargs: &mut Vec<ValueRef>)
926 -> Block<'blk, 'tcx> {
927 let _icx = push_ctxt("trans_arg_datum");
930 debug!("trans_arg_datum({:?})", arg_datum);
932 let arg = &fn_ty.args[*next_idx];
935 // Fill padding with undef value, where applicable.
936 if let Some(ty) = arg.pad {
937 llargs.push(C_undef(ty));
940 // Determine whether we want a by-ref datum even if not appropriate.
941 let want_by_ref = arg.is_indirect() || arg.cast.is_some();
943 let fat_ptr = common::type_is_fat_ptr(bcx.tcx(), arg_datum.ty);
944 let (by_ref, val) = if fat_ptr && !bcx.fcx.type_needs_drop(arg_datum.ty) {
945 (true, arg_datum.val)
947 // Make this an rvalue, since we are going to be
948 // passing ownership.
949 let arg_datum = unpack_datum!(
950 bcx, arg_datum.to_rvalue_datum(bcx, "arg"));
952 // Now that arg_datum is owned, get it into the appropriate
953 // mode (ref vs value).
954 let arg_datum = unpack_datum!(bcx, if want_by_ref {
955 arg_datum.to_ref_datum(bcx)
957 arg_datum.to_appropriate_datum(bcx)
960 // Technically, ownership of val passes to the callee.
961 // However, we must cleanup should we panic before the
962 // callee is actually invoked.
963 (arg_datum.kind.is_by_ref(),
964 arg_datum.add_clean(bcx.fcx, arg_cleanup_scope))
971 debug!("--- trans_arg_datum passing {:?}", Value(val));
974 // Fat pointers should be passed without any transformations.
975 assert!(!arg.is_indirect() && arg.cast.is_none());
976 llargs.push(Load(bcx, expr::get_dataptr(bcx, val)));
978 let info_arg = &fn_ty.args[*next_idx];
980 assert!(!info_arg.is_indirect() && info_arg.cast.is_none());
981 let info = Load(bcx, expr::get_meta(bcx, val));
983 if let Virtual(idx) = *callee {
984 // We have to grab the fn pointer from the vtable when
985 // handling the first argument, ensure that here.
986 assert_eq!(*next_idx, 2);
987 assert!(info_arg.is_ignore());
988 let fn_ptr = meth::get_virtual_method(bcx, info, idx);
989 let llty = fn_ty.llvm_type(bcx.ccx()).ptr_to();
990 *callee = Fn(PointerCast(bcx, fn_ptr, llty));
992 assert!(!info_arg.is_ignore());
999 if by_ref && !arg.is_indirect() {
1000 // Have to load the argument, maybe while casting it.
1001 if arg.original_ty == Type::i1(bcx.ccx()) {
1002 // We store bools as i8 so we need to truncate to i1.
1003 val = LoadRangeAssert(bcx, val, 0, 2, llvm::False);
1004 val = Trunc(bcx, val, arg.original_ty);
1005 } else if let Some(ty) = arg.cast {
1006 val = Load(bcx, PointerCast(bcx, val, ty.ptr_to()));
1007 if !bcx.unreachable.get() {
1008 let llalign = llalign_of_min(bcx.ccx(), arg.ty);
1010 llvm::LLVMSetAlignment(val, llalign);
1014 val = Load(bcx, val);