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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.
4 //
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.
10
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
15 //! closure.
16
17 pub use self::AutorefArg::*;
18 pub use self::CalleeData::*;
19 pub use self::CallArgs::*;
20
21 use arena::TypedArena;
22 use back::link;
23 use llvm::{self, ValueRef, get_params};
24 use middle::cstore::LOCAL_CRATE;
25 use middle::def::Def;
26 use middle::def_id::DefId;
27 use middle::infer;
28 use middle::subst;
29 use middle::subst::{Substs};
30 use rustc::front::map as hir_map;
31 use trans::adt;
32 use trans::base;
33 use trans::base::*;
34 use trans::build::*;
35 use trans::callee;
36 use trans::cleanup;
37 use trans::cleanup::CleanupMethods;
38 use trans::common::{self, Block, Result, NodeIdAndSpan, ExprId, CrateContext,
39 ExprOrMethodCall, FunctionContext, MethodCallKey};
40 use trans::consts;
41 use trans::datum::*;
42 use trans::debuginfo::{DebugLoc, ToDebugLoc};
43 use trans::declare;
44 use trans::expr;
45 use trans::glue;
46 use trans::inline;
47 use trans::foreign;
48 use trans::intrinsic;
49 use trans::meth;
50 use trans::monomorphize;
51 use trans::type_::Type;
52 use trans::type_of;
53 use trans::Disr;
54 use middle::ty::{self, Ty, TypeFoldable};
55 use middle::ty::MethodCall;
56 use rustc_front::hir;
57
58 use syntax::abi::Abi;
59 use syntax::ast;
60 use syntax::errors;
61 use syntax::ptr::P;
62
63 #[derive(Copy, Clone)]
64 pub struct MethodData {
65 pub llfn: ValueRef,
66 pub llself: ValueRef,
67 }
68
69 pub enum CalleeData<'tcx> {
70 // Constructor for enum variant/tuple-like-struct
71 // i.e. Some, Ok
72 NamedTupleConstructor(Disr),
73
74 // Represents a (possibly monomorphized) top-level fn item or method
75 // item. Note that this is just the fn-ptr and is not a Rust closure
76 // value (which is a pair).
77 Fn(/* llfn */ ValueRef),
78
79 Intrinsic(ast::NodeId, subst::Substs<'tcx>),
80
81 TraitItem(MethodData)
82 }
83
84 pub struct Callee<'blk, 'tcx: 'blk> {
85 pub bcx: Block<'blk, 'tcx>,
86 pub data: CalleeData<'tcx>,
87 pub ty: Ty<'tcx>
88 }
89
90 fn trans<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, expr: &hir::Expr)
91 -> Callee<'blk, 'tcx> {
92 let _icx = push_ctxt("trans_callee");
93 debug!("callee::trans(expr={:?})", expr);
94
95 // pick out special kinds of expressions that can be called:
96 match expr.node {
97 hir::ExprPath(..) => {
98 return trans_def(bcx, bcx.def(expr.id), expr);
99 }
100 _ => {}
101 }
102
103 // any other expressions are closures:
104 return datum_callee(bcx, expr);
105
106 fn datum_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, expr: &hir::Expr)
107 -> Callee<'blk, 'tcx> {
108 let DatumBlock { bcx, datum, .. } = expr::trans(bcx, expr);
109 match datum.ty.sty {
110 ty::TyBareFn(..) => {
111 Callee {
112 bcx: bcx,
113 ty: datum.ty,
114 data: Fn(datum.to_llscalarish(bcx))
115 }
116 }
117 _ => {
118 bcx.tcx().sess.span_bug(
119 expr.span,
120 &format!("type of callee is neither bare-fn nor closure: {}",
121 datum.ty));
122 }
123 }
124 }
125
126 fn fn_callee<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, datum: Datum<'tcx, Rvalue>)
127 -> Callee<'blk, 'tcx> {
128 Callee {
129 bcx: bcx,
130 data: Fn(datum.val),
131 ty: datum.ty
132 }
133 }
134
135 fn trans_def<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
136 def: Def,
137 ref_expr: &hir::Expr)
138 -> Callee<'blk, 'tcx> {
139 debug!("trans_def(def={:?}, ref_expr={:?})", def, ref_expr);
140 let expr_ty = common::node_id_type(bcx, ref_expr.id);
141 match def {
142 Def::Fn(did) if {
143 let maybe_def_id = inline::get_local_instance(bcx.ccx(), did);
144 let maybe_ast_node = maybe_def_id.and_then(|def_id| {
145 let node_id = bcx.tcx().map.as_local_node_id(def_id).unwrap();
146 bcx.tcx().map.find(node_id)
147 });
148 match maybe_ast_node {
149 Some(hir_map::NodeStructCtor(_)) => true,
150 _ => false
151 }
152 } => {
153 Callee {
154 bcx: bcx,
155 data: NamedTupleConstructor(Disr(0)),
156 ty: expr_ty
157 }
158 }
159 Def::Fn(did) if match expr_ty.sty {
160 ty::TyBareFn(_, ref f) => f.abi == Abi::RustIntrinsic ||
161 f.abi == Abi::PlatformIntrinsic,
162 _ => false
163 } => {
164 let substs = common::node_id_substs(bcx.ccx(),
165 ExprId(ref_expr.id),
166 bcx.fcx.param_substs);
167 let def_id = inline::maybe_instantiate_inline(bcx.ccx(), did);
168 let node_id = bcx.tcx().map.as_local_node_id(def_id).unwrap();
169 Callee { bcx: bcx, data: Intrinsic(node_id, substs), ty: expr_ty }
170 }
171 Def::Fn(did) => {
172 fn_callee(bcx, trans_fn_ref(bcx.ccx(), did, ExprId(ref_expr.id),
173 bcx.fcx.param_substs))
174 }
175 Def::Method(meth_did) => {
176 let method_item = bcx.tcx().impl_or_trait_item(meth_did);
177 let fn_datum = match method_item.container() {
178 ty::ImplContainer(_) => {
179 trans_fn_ref(bcx.ccx(), meth_did,
180 ExprId(ref_expr.id),
181 bcx.fcx.param_substs)
182 }
183 ty::TraitContainer(trait_did) => {
184 meth::trans_static_method_callee(bcx.ccx(),
185 meth_did,
186 trait_did,
187 ref_expr.id,
188 bcx.fcx.param_substs)
189 }
190 };
191 fn_callee(bcx, fn_datum)
192 }
193 Def::Variant(tid, vid) => {
194 let vinfo = bcx.tcx().lookup_adt_def(tid).variant_with_id(vid);
195 assert_eq!(vinfo.kind(), ty::VariantKind::Tuple);
196
197 Callee {
198 bcx: bcx,
199 data: NamedTupleConstructor(Disr::from(vinfo.disr_val)),
200 ty: expr_ty
201 }
202 }
203 Def::Struct(..) => {
204 Callee {
205 bcx: bcx,
206 data: NamedTupleConstructor(Disr(0)),
207 ty: expr_ty
208 }
209 }
210 Def::Static(..) |
211 Def::Const(..) |
212 Def::AssociatedConst(..) |
213 Def::Local(..) |
214 Def::Upvar(..) => {
215 datum_callee(bcx, ref_expr)
216 }
217 Def::Mod(..) | Def::ForeignMod(..) | Def::Trait(..) |
218 Def::Enum(..) | Def::TyAlias(..) | Def::PrimTy(..) |
219 Def::AssociatedTy(..) | Def::Label(..) | Def::TyParam(..) |
220 Def::SelfTy(..) | Def::Err => {
221 bcx.tcx().sess.span_bug(
222 ref_expr.span,
223 &format!("cannot translate def {:?} \
224 to a callable thing!", def));
225 }
226 }
227 }
228 }
229
230 /// Translates a reference (with id `ref_id`) to the fn/method with id `def_id` into a function
231 /// pointer. This may require monomorphization or inlining.
232 pub fn trans_fn_ref<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
233 def_id: DefId,
234 node: ExprOrMethodCall,
235 param_substs: &'tcx subst::Substs<'tcx>)
236 -> Datum<'tcx, Rvalue> {
237 let _icx = push_ctxt("trans_fn_ref");
238
239 let substs = common::node_id_substs(ccx, node, param_substs);
240 debug!("trans_fn_ref(def_id={:?}, node={:?}, substs={:?})",
241 def_id,
242 node,
243 substs);
244 trans_fn_ref_with_substs(ccx, def_id, node, param_substs, substs)
245 }
246
247 /// Translates an adapter that implements the `Fn` trait for a fn
248 /// pointer. This is basically the equivalent of something like:
249 ///
250 /// ```
251 /// impl<'a> Fn(&'a int) -> &'a int for fn(&int) -> &int {
252 /// extern "rust-abi" fn call(&self, args: (&'a int,)) -> &'a int {
253 /// (*self)(args.0)
254 /// }
255 /// }
256 /// ```
257 ///
258 /// but for the bare function type given.
259 pub fn trans_fn_pointer_shim<'a, 'tcx>(
260 ccx: &'a CrateContext<'a, 'tcx>,
261 closure_kind: ty::ClosureKind,
262 bare_fn_ty: Ty<'tcx>)
263 -> ValueRef
264 {
265 let _icx = push_ctxt("trans_fn_pointer_shim");
266 let tcx = ccx.tcx();
267
268 // Normalize the type for better caching.
269 let bare_fn_ty = tcx.erase_regions(&bare_fn_ty);
270
271 // If this is an impl of `Fn` or `FnMut` trait, the receiver is `&self`.
272 let is_by_ref = match closure_kind {
273 ty::FnClosureKind | ty::FnMutClosureKind => true,
274 ty::FnOnceClosureKind => false,
275 };
276 let bare_fn_ty_maybe_ref = if is_by_ref {
277 tcx.mk_imm_ref(tcx.mk_region(ty::ReStatic), bare_fn_ty)
278 } else {
279 bare_fn_ty
280 };
281
282 // Check if we already trans'd this shim.
283 match ccx.fn_pointer_shims().borrow().get(&bare_fn_ty_maybe_ref) {
284 Some(&llval) => { return llval; }
285 None => { }
286 }
287
288 debug!("trans_fn_pointer_shim(bare_fn_ty={:?})",
289 bare_fn_ty);
290
291 // Construct the "tuply" version of `bare_fn_ty`. It takes two arguments: `self`,
292 // which is the fn pointer, and `args`, which is the arguments tuple.
293 let (opt_def_id, sig) =
294 match bare_fn_ty.sty {
295 ty::TyBareFn(opt_def_id,
296 &ty::BareFnTy { unsafety: hir::Unsafety::Normal,
297 abi: Abi::Rust,
298 ref sig }) => {
299 (opt_def_id, sig)
300 }
301
302 _ => {
303 tcx.sess.bug(&format!("trans_fn_pointer_shim invoked on invalid type: {}",
304 bare_fn_ty));
305 }
306 };
307 let sig = tcx.erase_late_bound_regions(sig);
308 let sig = infer::normalize_associated_type(ccx.tcx(), &sig);
309 let tuple_input_ty = tcx.mk_tup(sig.inputs.to_vec());
310 let tuple_fn_ty = tcx.mk_fn(opt_def_id,
311 tcx.mk_bare_fn(ty::BareFnTy {
312 unsafety: hir::Unsafety::Normal,
313 abi: Abi::RustCall,
314 sig: ty::Binder(ty::FnSig {
315 inputs: vec![bare_fn_ty_maybe_ref,
316 tuple_input_ty],
317 output: sig.output,
318 variadic: false
319 })}));
320 debug!("tuple_fn_ty: {:?}", tuple_fn_ty);
321
322 //
323 let function_name = link::mangle_internal_name_by_type_and_seq(ccx, bare_fn_ty,
324 "fn_pointer_shim");
325 let llfn = declare::declare_internal_rust_fn(ccx, &function_name[..], tuple_fn_ty);
326
327 //
328 let empty_substs = tcx.mk_substs(Substs::trans_empty());
329 let (block_arena, fcx): (TypedArena<_>, FunctionContext);
330 block_arena = TypedArena::new();
331 fcx = new_fn_ctxt(ccx,
332 llfn,
333 ast::DUMMY_NODE_ID,
334 false,
335 sig.output,
336 empty_substs,
337 None,
338 &block_arena);
339 let mut bcx = init_function(&fcx, false, sig.output);
340
341 let llargs = get_params(fcx.llfn);
342
343 let self_idx = fcx.arg_offset();
344 // the first argument (`self`) will be ptr to the fn pointer
345 let llfnpointer = if is_by_ref {
346 Load(bcx, llargs[self_idx])
347 } else {
348 llargs[self_idx]
349 };
350
351 assert!(!fcx.needs_ret_allocas);
352
353 let dest = fcx.llretslotptr.get().map(|_|
354 expr::SaveIn(fcx.get_ret_slot(bcx, sig.output, "ret_slot"))
355 );
356
357 bcx = trans_call_inner(bcx, DebugLoc::None, |bcx, _| {
358 Callee {
359 bcx: bcx,
360 data: Fn(llfnpointer),
361 ty: bare_fn_ty
362 }
363 }, ArgVals(&llargs[(self_idx + 1)..]), dest).bcx;
364
365 finish_fn(&fcx, bcx, sig.output, DebugLoc::None);
366
367 ccx.fn_pointer_shims().borrow_mut().insert(bare_fn_ty_maybe_ref, llfn);
368
369 llfn
370 }
371
372 /// Translates a reference to a fn/method item, monomorphizing and
373 /// inlining as it goes.
374 ///
375 /// # Parameters
376 ///
377 /// - `ccx`: the crate context
378 /// - `def_id`: def id of the fn or method item being referenced
379 /// - `node`: node id of the reference to the fn/method, if applicable.
380 /// This parameter may be zero; but, if so, the resulting value may not
381 /// have the right type, so it must be cast before being used.
382 /// - `param_substs`: if the `node` is in a polymorphic function, these
383 /// are the substitutions required to monomorphize its type
384 /// - `substs`: values for each of the fn/method's parameters
385 pub fn trans_fn_ref_with_substs<'a, 'tcx>(
386 ccx: &CrateContext<'a, 'tcx>,
387 def_id: DefId,
388 node: ExprOrMethodCall,
389 param_substs: &'tcx subst::Substs<'tcx>,
390 substs: subst::Substs<'tcx>)
391 -> Datum<'tcx, Rvalue>
392 {
393 let _icx = push_ctxt("trans_fn_ref_with_substs");
394 let tcx = ccx.tcx();
395
396 debug!("trans_fn_ref_with_substs(def_id={:?}, node={:?}, \
397 param_substs={:?}, substs={:?})",
398 def_id,
399 node,
400 param_substs,
401 substs);
402
403 assert!(!substs.types.needs_infer());
404 assert!(!substs.types.has_escaping_regions());
405 let substs = substs.erase_regions();
406
407 // Check whether this fn has an inlined copy and, if so, redirect
408 // def_id to the local id of the inlined copy.
409 let def_id = inline::maybe_instantiate_inline(ccx, def_id);
410
411 fn is_named_tuple_constructor(tcx: &ty::ctxt, def_id: DefId) -> bool {
412 let node_id = match tcx.map.as_local_node_id(def_id) {
413 Some(n) => n,
414 None => { return false; }
415 };
416 let map_node = errors::expect(
417 &tcx.sess.diagnostic(),
418 tcx.map.find(node_id),
419 || "local item should be in ast map".to_string());
420
421 match map_node {
422 hir_map::NodeVariant(v) => {
423 v.node.data.is_tuple()
424 }
425 hir_map::NodeStructCtor(_) => true,
426 _ => false
427 }
428 }
429 let must_monomorphise =
430 !substs.types.is_empty() || is_named_tuple_constructor(tcx, def_id);
431
432 debug!("trans_fn_ref_with_substs({:?}) must_monomorphise: {}",
433 def_id, must_monomorphise);
434
435 // Create a monomorphic version of generic functions
436 if must_monomorphise {
437 // Should be either intra-crate or inlined.
438 assert_eq!(def_id.krate, LOCAL_CRATE);
439
440 let opt_ref_id = match node {
441 ExprId(id) => if id != 0 { Some(id) } else { None },
442 MethodCallKey(_) => None,
443 };
444
445 let substs = tcx.mk_substs(substs);
446 let (val, fn_ty, must_cast) =
447 monomorphize::monomorphic_fn(ccx, def_id, substs, opt_ref_id);
448 if must_cast && node != ExprId(0) {
449 // Monotype of the REFERENCE to the function (type params
450 // are subst'd)
451 let ref_ty = match node {
452 ExprId(id) => tcx.node_id_to_type(id),
453 MethodCallKey(method_call) => {
454 tcx.tables.borrow().method_map[&method_call].ty
455 }
456 };
457 let ref_ty = monomorphize::apply_param_substs(tcx,
458 param_substs,
459 &ref_ty);
460 let llptrty = type_of::type_of_fn_from_ty(ccx, ref_ty).ptr_to();
461 if llptrty != common::val_ty(val) {
462 let val = consts::ptrcast(val, llptrty);
463 return Datum::new(val, ref_ty, Rvalue::new(ByValue));
464 }
465 }
466 return Datum::new(val, fn_ty, Rvalue::new(ByValue));
467 }
468
469 // Type scheme of the function item (may have type params)
470 let fn_type_scheme = tcx.lookup_item_type(def_id);
471 let fn_type = infer::normalize_associated_type(tcx, &fn_type_scheme.ty);
472
473 // Find the actual function pointer.
474 let mut val = {
475 if let Some(node_id) = ccx.tcx().map.as_local_node_id(def_id) {
476 // Internal reference.
477 get_item_val(ccx, node_id)
478 } else {
479 // External reference.
480 trans_external_path(ccx, def_id, fn_type)
481 }
482 };
483
484 // This is subtle and surprising, but sometimes we have to bitcast
485 // the resulting fn pointer. The reason has to do with external
486 // functions. If you have two crates that both bind the same C
487 // library, they may not use precisely the same types: for
488 // example, they will probably each declare their own structs,
489 // which are distinct types from LLVM's point of view (nominal
490 // types).
491 //
492 // Now, if those two crates are linked into an application, and
493 // they contain inlined code, you can wind up with a situation
494 // where both of those functions wind up being loaded into this
495 // application simultaneously. In that case, the same function
496 // (from LLVM's point of view) requires two types. But of course
497 // LLVM won't allow one function to have two types.
498 //
499 // What we currently do, therefore, is declare the function with
500 // one of the two types (whichever happens to come first) and then
501 // bitcast as needed when the function is referenced to make sure
502 // it has the type we expect.
503 //
504 // This can occur on either a crate-local or crate-external
505 // reference. It also occurs when testing libcore and in some
506 // other weird situations. Annoying.
507 let llty = type_of::type_of_fn_from_ty(ccx, fn_type);
508 let llptrty = llty.ptr_to();
509 if common::val_ty(val) != llptrty {
510 debug!("trans_fn_ref_with_substs(): casting pointer!");
511 val = consts::ptrcast(val, llptrty);
512 } else {
513 debug!("trans_fn_ref_with_substs(): not casting pointer!");
514 }
515
516 Datum::new(val, fn_type, Rvalue::new(ByValue))
517 }
518
519 // ______________________________________________________________________
520 // Translating calls
521
522 pub fn trans_call<'a, 'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
523 call_expr: &hir::Expr,
524 f: &hir::Expr,
525 args: CallArgs<'a, 'tcx>,
526 dest: expr::Dest)
527 -> Block<'blk, 'tcx> {
528 let _icx = push_ctxt("trans_call");
529 trans_call_inner(bcx,
530 call_expr.debug_loc(),
531 |bcx, _| trans(bcx, f),
532 args,
533 Some(dest)).bcx
534 }
535
536 pub fn trans_method_call<'a, 'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
537 call_expr: &hir::Expr,
538 rcvr: &hir::Expr,
539 args: CallArgs<'a, 'tcx>,
540 dest: expr::Dest)
541 -> Block<'blk, 'tcx> {
542 let _icx = push_ctxt("trans_method_call");
543 debug!("trans_method_call(call_expr={:?})", call_expr);
544 let method_call = MethodCall::expr(call_expr.id);
545 trans_call_inner(
546 bcx,
547 call_expr.debug_loc(),
548 |cx, arg_cleanup_scope| {
549 meth::trans_method_callee(cx, method_call, Some(rcvr), arg_cleanup_scope)
550 },
551 args,
552 Some(dest)).bcx
553 }
554
555 pub fn trans_lang_call<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
556 did: DefId,
557 args: &[ValueRef],
558 dest: Option<expr::Dest>,
559 debug_loc: DebugLoc)
560 -> Result<'blk, 'tcx> {
561 callee::trans_call_inner(bcx, debug_loc, |bcx, _| {
562 let datum = trans_fn_ref_with_substs(bcx.ccx(),
563 did,
564 ExprId(0),
565 bcx.fcx.param_substs,
566 subst::Substs::trans_empty());
567 Callee {
568 bcx: bcx,
569 data: Fn(datum.val),
570 ty: datum.ty
571 }
572 }, ArgVals(args), dest)
573 }
574
575 /// This behemoth of a function translates function calls. Unfortunately, in
576 /// order to generate more efficient LLVM output at -O0, it has quite a complex
577 /// signature (refactoring this into two functions seems like a good idea).
578 ///
579 /// In particular, for lang items, it is invoked with a dest of None, and in
580 /// that case the return value contains the result of the fn. The lang item must
581 /// not return a structural type or else all heck breaks loose.
582 ///
583 /// For non-lang items, `dest` is always Some, and hence the result is written
584 /// into memory somewhere. Nonetheless we return the actual return value of the
585 /// function.
586 pub fn trans_call_inner<'a, 'blk, 'tcx, F>(bcx: Block<'blk, 'tcx>,
587 debug_loc: DebugLoc,
588 get_callee: F,
589 args: CallArgs<'a, 'tcx>,
590 dest: Option<expr::Dest>)
591 -> Result<'blk, 'tcx> where
592 F: FnOnce(Block<'blk, 'tcx>, cleanup::ScopeId) -> Callee<'blk, 'tcx>,
593 {
594 // Introduce a temporary cleanup scope that will contain cleanups
595 // for the arguments while they are being evaluated. The purpose
596 // this cleanup is to ensure that, should a panic occur while
597 // evaluating argument N, the values for arguments 0...N-1 are all
598 // cleaned up. If no panic occurs, the values are handed off to
599 // the callee, and hence none of the cleanups in this temporary
600 // scope will ever execute.
601 let fcx = bcx.fcx;
602 let ccx = fcx.ccx;
603 let arg_cleanup_scope = fcx.push_custom_cleanup_scope();
604
605 let callee = get_callee(bcx, cleanup::CustomScope(arg_cleanup_scope));
606 let mut bcx = callee.bcx;
607
608 let (abi, ret_ty) = match callee.ty.sty {
609 ty::TyBareFn(_, ref f) => {
610 let sig = bcx.tcx().erase_late_bound_regions(&f.sig);
611 let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
612 (f.abi, sig.output)
613 }
614 _ => panic!("expected bare rust fn or closure in trans_call_inner")
615 };
616
617 let (llfn, llself) = match callee.data {
618 Fn(llfn) => {
619 (llfn, None)
620 }
621 TraitItem(d) => {
622 (d.llfn, Some(d.llself))
623 }
624 Intrinsic(node, substs) => {
625 assert!(abi == Abi::RustIntrinsic || abi == Abi::PlatformIntrinsic);
626 assert!(dest.is_some());
627
628 let call_info = match debug_loc {
629 DebugLoc::At(id, span) => NodeIdAndSpan { id: id, span: span },
630 DebugLoc::None => {
631 bcx.sess().bug("No call info for intrinsic call?")
632 }
633 };
634
635 return intrinsic::trans_intrinsic_call(bcx, node, callee.ty,
636 arg_cleanup_scope, args,
637 dest.unwrap(), substs,
638 call_info);
639 }
640 NamedTupleConstructor(disr) => {
641 assert!(dest.is_some());
642 fcx.pop_custom_cleanup_scope(arg_cleanup_scope);
643
644 return base::trans_named_tuple_constructor(bcx,
645 callee.ty,
646 disr,
647 args,
648 dest.unwrap(),
649 debug_loc);
650 }
651 };
652
653 // Intrinsics should not become actual functions.
654 // We trans them in place in `trans_intrinsic_call`
655 assert!(abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic);
656
657 let is_rust_fn = abi == Abi::Rust || abi == Abi::RustCall;
658
659 // Generate a location to store the result. If the user does
660 // not care about the result, just make a stack slot.
661 let opt_llretslot = dest.and_then(|dest| match dest {
662 expr::SaveIn(dst) => Some(dst),
663 expr::Ignore => {
664 let ret_ty = match ret_ty {
665 ty::FnConverging(ret_ty) => ret_ty,
666 ty::FnDiverging => ccx.tcx().mk_nil()
667 };
668 if !is_rust_fn ||
669 type_of::return_uses_outptr(ccx, ret_ty) ||
670 bcx.fcx.type_needs_drop(ret_ty) {
671 // Push the out-pointer if we use an out-pointer for this
672 // return type, otherwise push "undef".
673 if common::type_is_zero_size(ccx, ret_ty) {
674 let llty = type_of::type_of(ccx, ret_ty);
675 Some(common::C_undef(llty.ptr_to()))
676 } else {
677 let llresult = alloc_ty(bcx, ret_ty, "__llret");
678 call_lifetime_start(bcx, llresult);
679 Some(llresult)
680 }
681 } else {
682 None
683 }
684 }
685 });
686
687 let mut llresult = unsafe {
688 llvm::LLVMGetUndef(Type::nil(ccx).ptr_to().to_ref())
689 };
690
691 // The code below invokes the function, using either the Rust
692 // conventions (if it is a rust fn) or the native conventions
693 // (otherwise). The important part is that, when all is said
694 // and done, either the return value of the function will have been
695 // written in opt_llretslot (if it is Some) or `llresult` will be
696 // set appropriately (otherwise).
697 if is_rust_fn {
698 let mut llargs = Vec::new();
699
700 if let (ty::FnConverging(ret_ty), Some(mut llretslot)) = (ret_ty, opt_llretslot) {
701 if type_of::return_uses_outptr(ccx, ret_ty) {
702 let llformal_ret_ty = type_of::type_of(ccx, ret_ty).ptr_to();
703 let llret_ty = common::val_ty(llretslot);
704 if llformal_ret_ty != llret_ty {
705 // this could happen due to e.g. subtyping
706 debug!("casting actual return type ({}) to match formal ({})",
707 bcx.llty_str(llret_ty), bcx.llty_str(llformal_ret_ty));
708 llretslot = PointerCast(bcx, llretslot, llformal_ret_ty);
709 }
710 llargs.push(llretslot);
711 }
712 }
713
714 // Push a trait object's self.
715 if let Some(llself) = llself {
716 llargs.push(llself);
717 }
718
719 // Push the arguments.
720 bcx = trans_args(bcx,
721 args,
722 callee.ty,
723 &mut llargs,
724 cleanup::CustomScope(arg_cleanup_scope),
725 llself.is_some(),
726 abi);
727
728 fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
729
730 // Invoke the actual rust fn and update bcx/llresult.
731 let (llret, b) = base::invoke(bcx,
732 llfn,
733 &llargs[..],
734 callee.ty,
735 debug_loc);
736 bcx = b;
737 llresult = llret;
738
739 // If the Rust convention for this type is return via
740 // the return value, copy it into llretslot.
741 match (opt_llretslot, ret_ty) {
742 (Some(llretslot), ty::FnConverging(ret_ty)) => {
743 if !type_of::return_uses_outptr(bcx.ccx(), ret_ty) &&
744 !common::type_is_zero_size(bcx.ccx(), ret_ty)
745 {
746 store_ty(bcx, llret, llretslot, ret_ty)
747 }
748 }
749 (_, _) => {}
750 }
751 } else {
752 // Lang items are the only case where dest is None, and
753 // they are always Rust fns.
754 assert!(dest.is_some());
755
756 let mut llargs = Vec::new();
757 let arg_tys = match args {
758 ArgExprs(a) => a.iter().map(|x| common::expr_ty_adjusted(bcx, &x)).collect(),
759 _ => panic!("expected arg exprs.")
760 };
761 bcx = trans_args(bcx,
762 args,
763 callee.ty,
764 &mut llargs,
765 cleanup::CustomScope(arg_cleanup_scope),
766 false,
767 abi);
768 fcx.scopes.borrow_mut().last_mut().unwrap().drop_non_lifetime_clean();
769
770 bcx = foreign::trans_native_call(bcx,
771 callee.ty,
772 llfn,
773 opt_llretslot.unwrap(),
774 &llargs[..],
775 arg_tys,
776 debug_loc);
777 }
778
779 fcx.pop_and_trans_custom_cleanup_scope(bcx, arg_cleanup_scope);
780
781 // If the caller doesn't care about the result of this fn call,
782 // drop the temporary slot we made.
783 match (dest, opt_llretslot, ret_ty) {
784 (Some(expr::Ignore), Some(llretslot), ty::FnConverging(ret_ty)) => {
785 // drop the value if it is not being saved.
786 bcx = glue::drop_ty(bcx,
787 llretslot,
788 ret_ty,
789 debug_loc);
790 call_lifetime_end(bcx, llretslot);
791 }
792 _ => {}
793 }
794
795 if ret_ty == ty::FnDiverging {
796 Unreachable(bcx);
797 }
798
799 Result::new(bcx, llresult)
800 }
801
802 pub enum CallArgs<'a, 'tcx> {
803 // Supply value of arguments as a list of expressions that must be
804 // translated. This is used in the common case of `foo(bar, qux)`.
805 ArgExprs(&'a [P<hir::Expr>]),
806
807 // Supply value of arguments as a list of LLVM value refs; frequently
808 // used with lang items and so forth, when the argument is an internal
809 // value.
810 ArgVals(&'a [ValueRef]),
811
812 // For overloaded operators: `(lhs, Option(rhs, rhs_id), autoref)`. `lhs`
813 // is the left-hand-side and `rhs/rhs_id` is the datum/expr-id of
814 // the right-hand-side argument (if any). `autoref` indicates whether the `rhs`
815 // arguments should be auto-referenced
816 ArgOverloadedOp(Datum<'tcx, Expr>, Option<(Datum<'tcx, Expr>, ast::NodeId)>, bool),
817
818 // Supply value of arguments as a list of expressions that must be
819 // translated, for overloaded call operators.
820 ArgOverloadedCall(Vec<&'a hir::Expr>),
821 }
822
823 fn trans_args_under_call_abi<'blk, 'tcx>(
824 mut bcx: Block<'blk, 'tcx>,
825 arg_exprs: &[P<hir::Expr>],
826 fn_ty: Ty<'tcx>,
827 llargs: &mut Vec<ValueRef>,
828 arg_cleanup_scope: cleanup::ScopeId,
829 ignore_self: bool)
830 -> Block<'blk, 'tcx>
831 {
832 let sig = bcx.tcx().erase_late_bound_regions(&fn_ty.fn_sig());
833 let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
834 let args = sig.inputs;
835
836 // Translate the `self` argument first.
837 if !ignore_self {
838 let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &arg_exprs[0]));
839 bcx = trans_arg_datum(bcx,
840 args[0],
841 arg_datum,
842 arg_cleanup_scope,
843 DontAutorefArg,
844 llargs);
845 }
846
847 // Now untuple the rest of the arguments.
848 let tuple_expr = &arg_exprs[1];
849 let tuple_type = common::node_id_type(bcx, tuple_expr.id);
850
851 match tuple_type.sty {
852 ty::TyTuple(ref field_types) => {
853 let tuple_datum = unpack_datum!(bcx,
854 expr::trans(bcx, &tuple_expr));
855 let tuple_lvalue_datum =
856 unpack_datum!(bcx,
857 tuple_datum.to_lvalue_datum(bcx,
858 "args",
859 tuple_expr.id));
860 let repr = adt::represent_type(bcx.ccx(), tuple_type);
861 let repr_ptr = &repr;
862 for (i, field_type) in field_types.iter().enumerate() {
863 let arg_datum = tuple_lvalue_datum.get_element(
864 bcx,
865 field_type,
866 |srcval| {
867 adt::trans_field_ptr(bcx, repr_ptr, srcval, Disr(0), i)
868 }).to_expr_datum();
869 bcx = trans_arg_datum(bcx,
870 field_type,
871 arg_datum,
872 arg_cleanup_scope,
873 DontAutorefArg,
874 llargs);
875 }
876 }
877 _ => {
878 bcx.sess().span_bug(tuple_expr.span,
879 "argument to `.call()` wasn't a tuple?!")
880 }
881 };
882
883 bcx
884 }
885
886 fn trans_overloaded_call_args<'blk, 'tcx>(
887 mut bcx: Block<'blk, 'tcx>,
888 arg_exprs: Vec<&hir::Expr>,
889 fn_ty: Ty<'tcx>,
890 llargs: &mut Vec<ValueRef>,
891 arg_cleanup_scope: cleanup::ScopeId,
892 ignore_self: bool)
893 -> Block<'blk, 'tcx> {
894 // Translate the `self` argument first.
895 let sig = bcx.tcx().erase_late_bound_regions(&fn_ty.fn_sig());
896 let sig = infer::normalize_associated_type(bcx.tcx(), &sig);
897 let arg_tys = sig.inputs;
898
899 if !ignore_self {
900 let arg_datum = unpack_datum!(bcx, expr::trans(bcx, arg_exprs[0]));
901 bcx = trans_arg_datum(bcx,
902 arg_tys[0],
903 arg_datum,
904 arg_cleanup_scope,
905 DontAutorefArg,
906 llargs);
907 }
908
909 // Now untuple the rest of the arguments.
910 let tuple_type = arg_tys[1];
911 match tuple_type.sty {
912 ty::TyTuple(ref field_types) => {
913 for (i, &field_type) in field_types.iter().enumerate() {
914 let arg_datum =
915 unpack_datum!(bcx, expr::trans(bcx, arg_exprs[i + 1]));
916 bcx = trans_arg_datum(bcx,
917 field_type,
918 arg_datum,
919 arg_cleanup_scope,
920 DontAutorefArg,
921 llargs);
922 }
923 }
924 _ => {
925 bcx.sess().span_bug(arg_exprs[0].span,
926 "argument to `.call()` wasn't a tuple?!")
927 }
928 };
929
930 bcx
931 }
932
933 pub fn trans_args<'a, 'blk, 'tcx>(cx: Block<'blk, 'tcx>,
934 args: CallArgs<'a, 'tcx>,
935 fn_ty: Ty<'tcx>,
936 llargs: &mut Vec<ValueRef>,
937 arg_cleanup_scope: cleanup::ScopeId,
938 ignore_self: bool,
939 abi: Abi)
940 -> Block<'blk, 'tcx> {
941 debug!("trans_args(abi={})", abi);
942
943 let _icx = push_ctxt("trans_args");
944 let sig = cx.tcx().erase_late_bound_regions(&fn_ty.fn_sig());
945 let sig = infer::normalize_associated_type(cx.tcx(), &sig);
946 let arg_tys = sig.inputs;
947 let variadic = sig.variadic;
948
949 let mut bcx = cx;
950
951 // First we figure out the caller's view of the types of the arguments.
952 // This will be needed if this is a generic call, because the callee has
953 // to cast her view of the arguments to the caller's view.
954 match args {
955 ArgExprs(arg_exprs) => {
956 if abi == Abi::RustCall {
957 // This is only used for direct calls to the `call`,
958 // `call_mut` or `call_once` functions.
959 return trans_args_under_call_abi(cx,
960 arg_exprs,
961 fn_ty,
962 llargs,
963 arg_cleanup_scope,
964 ignore_self)
965 }
966
967 let num_formal_args = arg_tys.len();
968 for (i, arg_expr) in arg_exprs.iter().enumerate() {
969 if i == 0 && ignore_self {
970 continue;
971 }
972 let arg_ty = if i >= num_formal_args {
973 assert!(variadic);
974 common::expr_ty_adjusted(cx, &arg_expr)
975 } else {
976 arg_tys[i]
977 };
978
979 let arg_datum = unpack_datum!(bcx, expr::trans(bcx, &arg_expr));
980 bcx = trans_arg_datum(bcx, arg_ty, arg_datum,
981 arg_cleanup_scope,
982 DontAutorefArg,
983 llargs);
984 }
985 }
986 ArgOverloadedCall(arg_exprs) => {
987 return trans_overloaded_call_args(cx,
988 arg_exprs,
989 fn_ty,
990 llargs,
991 arg_cleanup_scope,
992 ignore_self)
993 }
994 ArgOverloadedOp(lhs, rhs, autoref) => {
995 assert!(!variadic);
996
997 bcx = trans_arg_datum(bcx, arg_tys[0], lhs,
998 arg_cleanup_scope,
999 DontAutorefArg,
1000 llargs);
1001
1002 if let Some((rhs, rhs_id)) = rhs {
1003 assert_eq!(arg_tys.len(), 2);
1004 bcx = trans_arg_datum(bcx, arg_tys[1], rhs,
1005 arg_cleanup_scope,
1006 if autoref { DoAutorefArg(rhs_id) } else { DontAutorefArg },
1007 llargs);
1008 } else {
1009 assert_eq!(arg_tys.len(), 1);
1010 }
1011 }
1012 ArgVals(vs) => {
1013 llargs.extend_from_slice(vs);
1014 }
1015 }
1016
1017 bcx
1018 }
1019
1020 #[derive(Copy, Clone)]
1021 pub enum AutorefArg {
1022 DontAutorefArg,
1023 DoAutorefArg(ast::NodeId)
1024 }
1025
1026 pub fn trans_arg_datum<'blk, 'tcx>(bcx: Block<'blk, 'tcx>,
1027 formal_arg_ty: Ty<'tcx>,
1028 arg_datum: Datum<'tcx, Expr>,
1029 arg_cleanup_scope: cleanup::ScopeId,
1030 autoref_arg: AutorefArg,
1031 llargs: &mut Vec<ValueRef>)
1032 -> Block<'blk, 'tcx> {
1033 let _icx = push_ctxt("trans_arg_datum");
1034 let mut bcx = bcx;
1035 let ccx = bcx.ccx();
1036
1037 debug!("trans_arg_datum({:?})",
1038 formal_arg_ty);
1039
1040 let arg_datum_ty = arg_datum.ty;
1041
1042 debug!(" arg datum: {}", arg_datum.to_string(bcx.ccx()));
1043
1044 let mut val;
1045 // FIXME(#3548) use the adjustments table
1046 match autoref_arg {
1047 DoAutorefArg(arg_id) => {
1048 // We will pass argument by reference
1049 // We want an lvalue, so that we can pass by reference and
1050 let arg_datum = unpack_datum!(
1051 bcx, arg_datum.to_lvalue_datum(bcx, "arg", arg_id));
1052 val = arg_datum.val;
1053 }
1054 DontAutorefArg if common::type_is_fat_ptr(bcx.tcx(), arg_datum_ty) &&
1055 !bcx.fcx.type_needs_drop(arg_datum_ty) => {
1056 val = arg_datum.val
1057 }
1058 DontAutorefArg => {
1059 // Make this an rvalue, since we are going to be
1060 // passing ownership.
1061 let arg_datum = unpack_datum!(
1062 bcx, arg_datum.to_rvalue_datum(bcx, "arg"));
1063
1064 // Now that arg_datum is owned, get it into the appropriate
1065 // mode (ref vs value).
1066 let arg_datum = unpack_datum!(
1067 bcx, arg_datum.to_appropriate_datum(bcx));
1068
1069 // Technically, ownership of val passes to the callee.
1070 // However, we must cleanup should we panic before the
1071 // callee is actually invoked.
1072 val = arg_datum.add_clean(bcx.fcx, arg_cleanup_scope);
1073 }
1074 }
1075
1076 if type_of::arg_is_indirect(ccx, formal_arg_ty) && formal_arg_ty != arg_datum_ty {
1077 // this could happen due to e.g. subtyping
1078 let llformal_arg_ty = type_of::type_of_explicit_arg(ccx, formal_arg_ty);
1079 debug!("casting actual type ({}) to match formal ({})",
1080 bcx.val_to_string(val), bcx.llty_str(llformal_arg_ty));
1081 debug!("Rust types: {:?}; {:?}", arg_datum_ty,
1082 formal_arg_ty);
1083 val = PointerCast(bcx, val, llformal_arg_ty);
1084 }
1085
1086 debug!("--- trans_arg_datum passing {}", bcx.val_to_string(val));
1087
1088 if common::type_is_fat_ptr(bcx.tcx(), formal_arg_ty) {
1089 llargs.push(Load(bcx, expr::get_dataptr(bcx, val)));
1090 llargs.push(Load(bcx, expr::get_meta(bcx, val)));
1091 } else {
1092 llargs.push(val);
1093 }
1094
1095 bcx
1096 }