1 // Copyright 2012-2013 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.
13 // Code relating to taking, dropping, etc as well as type descriptors.
18 use lib::llvm::{llvm, ValueRef, True};
20 use middle::lang_items::{FreeFnLangItem, ExchangeFreeFnLangItem};
21 use middle::trans::adt;
22 use middle::trans::base::*;
23 use middle::trans::build::*;
24 use middle::trans::callee;
25 use middle::trans::cleanup;
26 use middle::trans::cleanup::CleanupMethods;
27 use middle::trans::common::*;
28 use middle::trans::expr;
29 use middle::trans::machine::*;
30 use middle::trans::reflect;
31 use middle::trans::tvec;
32 use middle::trans::type_::Type;
33 use middle::trans::type_of::type_of;
35 use util::ppaux::ty_to_short_str;
38 use arena::TypedArena;
39 use std::c_str::ToCStr;
41 use std::libc::c_uint;
43 use syntax::parse::token;
45 pub fn trans_free<'a>(cx: &'a Block<'a>, v: ValueRef) -> &'a Block<'a> {
46 let _icx = push_ctxt("trans_free");
47 callee::trans_lang_call(cx,
48 langcall(cx, None, "", FreeFnLangItem),
49 [PointerCast(cx, v, Type::i8p())],
50 Some(expr::Ignore)).bcx
53 pub fn trans_exchange_free<'a>(cx: &'a Block<'a>, v: ValueRef)
55 let _icx = push_ctxt("trans_exchange_free");
56 callee::trans_lang_call(cx,
57 langcall(cx, None, "", ExchangeFreeFnLangItem),
58 [PointerCast(cx, v, Type::i8p())],
59 Some(expr::Ignore)).bcx
62 pub fn take_ty<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
64 // NB: v is an *alias* of type t here, not a direct value.
65 let _icx = push_ctxt("take_ty");
66 match ty::get(t).sty {
68 ty::ty_vec(_, ty::vstore_box) | ty::ty_str(ty::vstore_box) => {
69 incr_refcnt_of_boxed(bcx, v)
71 ty::ty_trait(_, _, ty::BoxTraitStore, _, _) => {
72 incr_refcnt_of_boxed(bcx, GEPi(bcx, v, [0u, abi::trt_field_box]))
74 _ if ty::type_is_structural(t)
75 && ty::type_needs_drop(bcx.tcx(), t) => {
76 iter_structural_ty(bcx, v, t, take_ty)
82 pub fn drop_ty<'a>(cx: &'a Block<'a>, v: ValueRef, t: ty::t)
84 // NB: v is an *alias* of type t here, not a direct value.
85 let _icx = push_ctxt("drop_ty");
86 if ty::type_needs_drop(cx.tcx(), t) {
87 return call_tydesc_glue(cx, v, t, abi::tydesc_field_drop_glue);
92 pub fn drop_ty_immediate<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
94 let _icx = push_ctxt("drop_ty_immediate");
95 let vp = alloca(bcx, type_of(bcx.ccx(), t), "");
100 pub fn lazily_emit_all_tydesc_glue(ccx: @CrateContext,
101 static_ti: @tydesc_info) {
102 lazily_emit_tydesc_glue(ccx, abi::tydesc_field_drop_glue, static_ti);
103 lazily_emit_tydesc_glue(ccx, abi::tydesc_field_visit_glue, static_ti);
106 fn simplified_glue_type(tcx: ty::ctxt, field: uint, t: ty::t) -> ty::t {
107 if field == abi::tydesc_field_drop_glue {
108 if !ty::type_needs_drop(tcx, t) {
111 match ty::get(t).sty {
113 if !ty::type_needs_drop(tcx, typ) =>
114 return ty::mk_box(tcx, ty::mk_nil()),
116 ty::ty_vec(mt, ty::vstore_box)
117 if !ty::type_needs_drop(tcx, mt.ty) =>
118 return ty::mk_box(tcx, ty::mk_nil()),
121 if !ty::type_needs_drop(tcx, typ) =>
122 return ty::mk_uniq(tcx, ty::mk_nil()),
124 ty::ty_vec(mt, ty::vstore_uniq)
125 if !ty::type_needs_drop(tcx, mt.ty) =>
126 return ty::mk_uniq(tcx, ty::mk_nil()),
135 pub fn lazily_emit_tydesc_glue(ccx: @CrateContext, field: uint, ti: @tydesc_info) {
136 let _icx = push_ctxt("lazily_emit_tydesc_glue");
138 let simpl = simplified_glue_type(ccx.tcx, field, ti.ty);
140 let _icx = push_ctxt("lazily_emit_simplified_tydesc_glue");
141 let simpl_ti = get_tydesc(ccx, simpl);
142 lazily_emit_tydesc_glue(ccx, field, simpl_ti);
144 if field == abi::tydesc_field_drop_glue {
145 ti.drop_glue.set(simpl_ti.drop_glue.get());
146 } else if field == abi::tydesc_field_visit_glue {
147 ti.visit_glue.set(simpl_ti.visit_glue.get());
153 let llfnty = Type::glue_fn(type_of(ccx, ti.ty).ptr_to());
155 if field == abi::tydesc_field_drop_glue {
156 match ti.drop_glue.get() {
159 debug!("+++ lazily_emit_tydesc_glue DROP {}",
160 ppaux::ty_to_str(ccx.tcx, ti.ty));
161 let glue_fn = declare_generic_glue(ccx, ti.ty, llfnty, "drop");
162 ti.drop_glue.set(Some(glue_fn));
163 make_generic_glue(ccx, ti.ty, glue_fn, make_drop_glue, "drop");
164 debug!("--- lazily_emit_tydesc_glue DROP {}",
165 ppaux::ty_to_str(ccx.tcx, ti.ty));
168 } else if field == abi::tydesc_field_visit_glue {
169 match ti.visit_glue.get() {
172 debug!("+++ lazily_emit_tydesc_glue VISIT {}",
173 ppaux::ty_to_str(ccx.tcx, ti.ty));
174 let glue_fn = declare_generic_glue(ccx, ti.ty, llfnty, "visit");
175 ti.visit_glue.set(Some(glue_fn));
176 make_generic_glue(ccx, ti.ty, glue_fn, make_visit_glue, "visit");
177 debug!("--- lazily_emit_tydesc_glue VISIT {}",
178 ppaux::ty_to_str(ccx.tcx, ti.ty));
184 // See [Note-arg-mode]
185 pub fn call_tydesc_glue_full(bcx: &Block, v: ValueRef, tydesc: ValueRef,
186 field: uint, static_ti: Option<@tydesc_info>) {
187 let _icx = push_ctxt("call_tydesc_glue_full");
189 // NB: Don't short-circuit even if this block is unreachable because
190 // GC-based cleanup needs to the see that the roots are live.
191 if bcx.unreachable.get() && !ccx.sess.no_landing_pads() { return; }
193 let static_glue_fn = match static_ti {
196 lazily_emit_tydesc_glue(ccx, field, sti);
197 if field == abi::tydesc_field_drop_glue {
199 } else if field == abi::tydesc_field_visit_glue {
207 // When static type info is available, avoid casting parameter unless the
208 // glue is using a simplified type, because the function already has the
209 // right type. Otherwise cast to generic pointer.
210 let llrawptr = if static_glue_fn.is_none() {
211 PointerCast(bcx, v, Type::i8p())
213 let ty = static_ti.unwrap().ty;
214 let simpl = simplified_glue_type(ccx.tcx, field, ty);
216 PointerCast(bcx, v, type_of(ccx, simpl).ptr_to())
223 match static_glue_fn {
225 // Select out the glue function to call from the tydesc
226 let llfnptr = GEPi(bcx, tydesc, [0u, field]);
233 Call(bcx, llfn, [llrawptr], []);
236 // See [Note-arg-mode]
237 fn call_tydesc_glue<'a>(cx: &'a Block<'a>, v: ValueRef, t: ty::t, field: uint)
239 let _icx = push_ctxt("call_tydesc_glue");
240 let ti = get_tydesc(cx.ccx(), t);
241 call_tydesc_glue_full(cx, v, ti.tydesc, field, Some(ti));
245 fn make_visit_glue<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
247 let _icx = push_ctxt("make_visit_glue");
249 let (visitor_trait, object_ty) = match ty::visitor_object_ty(bcx.tcx(),
253 bcx.tcx().sess.fatal(s);
256 let v = PointerCast(bcx, v, type_of(bcx.ccx(), object_ty).ptr_to());
257 bcx = reflect::emit_calls_to_trait_visit_ty(bcx, t, v, visitor_trait.def_id);
261 fn trans_struct_drop_flag<'a>(bcx: &'a Block<'a>,
264 dtor_did: ast::DefId,
265 class_did: ast::DefId,
268 let repr = adt::represent_type(bcx.ccx(), t);
269 let drop_flag = adt::trans_drop_flag_ptr(bcx, repr, v0);
270 with_cond(bcx, IsNotNull(bcx, Load(bcx, drop_flag)), |cx| {
271 trans_struct_drop(cx, t, v0, dtor_did, class_did, substs)
275 fn trans_struct_drop<'a>(bcx: &'a Block<'a>,
278 dtor_did: ast::DefId,
279 class_did: ast::DefId,
282 let repr = adt::represent_type(bcx.ccx(), t);
284 // Find and call the actual destructor
285 let dtor_addr = get_res_dtor(bcx.ccx(), dtor_did,
286 class_did, substs.tps.clone());
288 // The second argument is the "self" argument for drop
289 let params = unsafe {
290 let ty = Type::from_ref(llvm::LLVMTypeOf(dtor_addr));
291 ty.element_type().func_params()
294 // Class dtors have no explicit args, so the params should
295 // just consist of the environment (self)
296 assert_eq!(params.len(), 1);
298 // Be sure to put all of the fields into a scope so we can use an invoke
299 // instruction to call the user destructor but still call the field
300 // destructors if the user destructor fails.
301 let field_scope = bcx.fcx.push_custom_cleanup_scope();
303 let self_arg = PointerCast(bcx, v0, params[0]);
304 let args = ~[self_arg];
306 // Add all the fields as a value which needs to be cleaned at the end of
308 let field_tys = ty::struct_fields(bcx.tcx(), class_did, substs);
309 for (i, fld) in field_tys.iter().enumerate() {
310 let llfld_a = adt::trans_field_ptr(bcx, repr, v0, 0, i);
311 bcx.fcx.schedule_drop_mem(cleanup::CustomScope(field_scope),
316 let (_, bcx) = invoke(bcx, dtor_addr, args, [], None);
318 bcx.fcx.pop_and_trans_custom_cleanup_scope(bcx, field_scope)
321 fn make_drop_glue<'a>(bcx: &'a Block<'a>, v0: ValueRef, t: ty::t) -> &'a Block<'a> {
322 // NB: v0 is an *alias* of type t here, not a direct value.
323 let _icx = push_ctxt("make_drop_glue");
325 match ty::get(t).sty {
326 ty::ty_box(body_ty) => {
327 decr_refcnt_maybe_free(bcx, v0, Some(body_ty))
329 ty::ty_str(ty::vstore_box) | ty::ty_vec(_, ty::vstore_box) => {
330 let unit_ty = ty::sequence_element_type(ccx.tcx, t);
331 let unboxed_vec_ty = ty::mk_mut_unboxed_vec(ccx.tcx, unit_ty);
332 decr_refcnt_maybe_free(bcx, v0, Some(unboxed_vec_ty))
334 ty::ty_uniq(content_ty) => {
335 let llbox = Load(bcx, v0);
336 let not_null = IsNotNull(bcx, llbox);
337 with_cond(bcx, not_null, |bcx| {
338 let bcx = drop_ty(bcx, llbox, content_ty);
339 trans_exchange_free(bcx, llbox)
342 ty::ty_vec(_, ty::vstore_uniq) | ty::ty_str(ty::vstore_uniq) => {
343 make_drop_glue(bcx, v0, tvec::expand_boxed_vec_ty(bcx.tcx(), t))
345 ty::ty_unboxed_vec(_) => {
346 tvec::make_drop_glue_unboxed(bcx, v0, t)
348 ty::ty_struct(did, ref substs) => {
350 match ty::ty_dtor(tcx, did) {
351 ty::TraitDtor(dtor, true) => {
352 trans_struct_drop_flag(bcx, t, v0, dtor, did, substs)
354 ty::TraitDtor(dtor, false) => {
355 trans_struct_drop(bcx, t, v0, dtor, did, substs)
358 // No dtor? Just the default case
359 iter_structural_ty(bcx, v0, t, drop_ty)
363 ty::ty_trait(_, _, ty::BoxTraitStore, _, _) => {
364 let llbox_ptr = GEPi(bcx, v0, [0u, abi::trt_field_box]);
365 decr_refcnt_maybe_free(bcx, llbox_ptr, None)
367 ty::ty_trait(_, _, ty::UniqTraitStore, _, _) => {
368 let lluniquevalue = GEPi(bcx, v0, [0, abi::trt_field_box]);
369 // Only drop the value when it is non-null
370 with_cond(bcx, IsNotNull(bcx, Load(bcx, lluniquevalue)), |bcx| {
371 let lldtor_ptr = Load(bcx, GEPi(bcx, v0, [0, abi::trt_field_vtable]));
372 let lldtor = Load(bcx, lldtor_ptr);
373 Call(bcx, lldtor, [PointerCast(bcx, lluniquevalue, Type::i8p())], []);
377 ty::ty_closure(ref f) if f.sigil == ast::OwnedSigil => {
378 let box_cell_v = GEPi(bcx, v0, [0u, abi::fn_field_box]);
379 let env = Load(bcx, box_cell_v);
380 let env_ptr_ty = Type::at_box(ccx, Type::i8()).ptr_to();
381 let env = PointerCast(bcx, env, env_ptr_ty);
382 with_cond(bcx, IsNotNull(bcx, env), |bcx| {
383 // Load the type descr found in the env
384 let lltydescty = ccx.tydesc_type.ptr_to();
385 let tydescptr = GEPi(bcx, env, [0u, abi::box_field_tydesc]);
386 let tydesc = Load(bcx, tydescptr);
387 let tydesc = PointerCast(bcx, tydesc, lltydescty);
389 // Drop the tuple data then free the descriptor
390 let cdata = GEPi(bcx, env, [0u, abi::box_field_body]);
391 call_tydesc_glue_full(bcx, cdata, tydesc,
392 abi::tydesc_field_drop_glue, None);
394 // Free the ty descr (if necc) and the env itself
395 trans_exchange_free(bcx, env)
399 if ty::type_needs_drop(ccx.tcx, t) &&
400 ty::type_is_structural(t) {
401 iter_structural_ty(bcx, v0, t, drop_ty)
409 fn decr_refcnt_maybe_free<'a>(bcx: &'a Block<'a>, box_ptr_ptr: ValueRef,
410 t: Option<ty::t>) -> &'a Block<'a> {
411 let _icx = push_ctxt("decr_refcnt_maybe_free");
415 let decr_bcx = fcx.new_temp_block("decr");
416 let free_bcx = fcx.new_temp_block("free");
417 let next_bcx = fcx.new_temp_block("next");
419 let box_ptr = Load(bcx, box_ptr_ptr);
420 let llnotnull = IsNotNull(bcx, box_ptr);
421 CondBr(bcx, llnotnull, decr_bcx.llbb, next_bcx.llbb);
423 let rc_ptr = GEPi(decr_bcx, box_ptr, [0u, abi::box_field_refcnt]);
424 let rc = Sub(decr_bcx, Load(decr_bcx, rc_ptr), C_int(ccx, 1));
425 Store(decr_bcx, rc, rc_ptr);
426 CondBr(decr_bcx, IsNull(decr_bcx, rc), free_bcx.llbb, next_bcx.llbb);
428 let v = Load(free_bcx, box_ptr_ptr);
429 let body = GEPi(free_bcx, v, [0u, abi::box_field_body]);
430 let free_bcx = match t {
431 Some(t) => drop_ty(free_bcx, body, t),
433 // Generate code that, dynamically, indexes into the
434 // tydesc and calls the drop glue that got set dynamically
435 let td = Load(free_bcx, GEPi(free_bcx, v, [0u, abi::box_field_tydesc]));
436 call_tydesc_glue_full(free_bcx, body, td, abi::tydesc_field_drop_glue, None);
440 let free_bcx = trans_free(free_bcx, v);
441 Br(free_bcx, next_bcx.llbb);
446 fn incr_refcnt_of_boxed<'a>(bcx: &'a Block<'a>,
447 box_ptr_ptr: ValueRef) -> &'a Block<'a> {
448 let _icx = push_ctxt("incr_refcnt_of_boxed");
450 let box_ptr = Load(bcx, box_ptr_ptr);
451 let rc_ptr = GEPi(bcx, box_ptr, [0u, abi::box_field_refcnt]);
452 let rc = Load(bcx, rc_ptr);
453 let rc = Add(bcx, rc, C_int(ccx, 1));
454 Store(bcx, rc, rc_ptr);
459 // Generates the declaration for (but doesn't emit) a type descriptor.
460 pub fn declare_tydesc(ccx: &CrateContext, t: ty::t) -> @tydesc_info {
461 // If emit_tydescs already ran, then we shouldn't be creating any new
463 assert!(!ccx.finished_tydescs.get());
465 let llty = type_of(ccx, t);
467 if ccx.sess.count_type_sizes() {
468 println!("{}\t{}", llsize_of_real(ccx, llty),
469 ppaux::ty_to_str(ccx.tcx, t));
472 let llsize = llsize_of(ccx, llty);
473 let llalign = llalign_of(ccx, llty);
474 let name = mangle_internal_name_by_type_and_seq(ccx, t, "tydesc").to_managed();
475 note_unique_llvm_symbol(ccx, name);
476 debug!("+++ declare_tydesc {} {}", ppaux::ty_to_str(ccx.tcx, t), name);
477 let gvar = name.with_c_str(|buf| {
479 llvm::LLVMAddGlobal(ccx.llmod, ccx.tydesc_type.to_ref(), buf)
483 let ty_name = token::intern_and_get_ident(ppaux::ty_to_str(ccx.tcx, t));
484 let ty_name = C_str_slice(ccx, ty_name);
486 let inf = @tydesc_info {
492 drop_glue: Cell::new(None),
493 visit_glue: Cell::new(None),
495 debug!("--- declare_tydesc {}", ppaux::ty_to_str(ccx.tcx, t));
499 fn declare_generic_glue(ccx: &CrateContext, t: ty::t, llfnty: Type,
500 name: &str) -> ValueRef {
501 let _icx = push_ctxt("declare_generic_glue");
502 let fn_nm = mangle_internal_name_by_type_and_seq(ccx, t, (~"glue_" + name)).to_managed();
503 debug!("{} is for type {}", fn_nm, ppaux::ty_to_str(ccx.tcx, t));
504 note_unique_llvm_symbol(ccx, fn_nm);
505 let llfn = decl_cdecl_fn(ccx.llmod, fn_nm, llfnty, ty::mk_nil());
509 fn make_generic_glue(ccx: @CrateContext,
512 helper: <'a> |&'a Block<'a>, ValueRef, ty::t|
516 let _icx = push_ctxt("make_generic_glue");
517 let glue_name = format!("glue {} {}", name, ty_to_short_str(ccx.tcx, t));
518 let _s = StatRecorder::new(ccx, glue_name);
520 let arena = TypedArena::new();
521 let fcx = new_fn_ctxt(ccx, ~[], llfn, -1, false, ty::mk_nil(), None, None,
524 init_function(&fcx, false, ty::mk_nil(), None);
526 lib::llvm::SetLinkage(llfn, lib::llvm::InternalLinkage);
527 ccx.stats.n_glues_created.set(ccx.stats.n_glues_created.get() + 1u);
528 // All glue functions take values passed *by alias*; this is a
529 // requirement since in many contexts glue is invoked indirectly and
530 // the caller has no idea if it's dealing with something that can be
533 // llfn is expected be declared to take a parameter of the appropriate
534 // type, so we don't need to explicitly cast the function parameter.
536 let bcx = fcx.entry_bcx.get().unwrap();
537 let llrawptr0 = unsafe { llvm::LLVMGetParam(llfn, fcx.arg_pos(0) as c_uint) };
538 let bcx = helper(bcx, llrawptr0, t);
539 finish_fn(&fcx, bcx);
544 pub fn emit_tydescs(ccx: &CrateContext) {
545 let _icx = push_ctxt("emit_tydescs");
546 // As of this point, allow no more tydescs to be created.
547 ccx.finished_tydescs.set(true);
548 let glue_fn_ty = Type::generic_glue_fn(ccx).ptr_to();
549 let mut tyds = ccx.tydescs.borrow_mut();
550 for (_, &val) in tyds.get().iter() {
553 // Each of the glue functions needs to be cast to a generic type
554 // before being put into the tydesc because we only have a singleton
555 // tydesc type. Then we'll recast each function to its real type when
558 match ti.drop_glue.get() {
560 ccx.stats.n_null_glues.set(ccx.stats.n_null_glues.get() +
566 ccx.stats.n_real_glues.set(ccx.stats.n_real_glues.get() +
568 llvm::LLVMConstPointerCast(v, glue_fn_ty.to_ref())
573 match ti.visit_glue.get() {
575 ccx.stats.n_null_glues.set(ccx.stats.n_null_glues.get() +
581 ccx.stats.n_real_glues.set(ccx.stats.n_real_glues.get() +
583 llvm::LLVMConstPointerCast(v, glue_fn_ty.to_ref())
588 let tydesc = C_named_struct(ccx.tydesc_type,
591 drop_glue, // drop_glue
592 visit_glue, // visit_glue
596 let gvar = ti.tydesc;
597 llvm::LLVMSetInitializer(gvar, tydesc);
598 llvm::LLVMSetGlobalConstant(gvar, True);
599 lib::llvm::SetLinkage(gvar, lib::llvm::InternalLinkage);