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, sizing_type_of};
35 use util::ppaux::ty_to_short_str;
38 use arena::TypedArena;
39 use std::c_str::ToCStr;
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(cx.ccx()))],
50 Some(expr::Ignore)).bcx
53 fn trans_exchange_free<'a>(cx: &'a Block<'a>, v: ValueRef, size: u64,
54 align: u64) -> &'a Block<'a> {
55 let _icx = push_ctxt("trans_exchange_free");
57 callee::trans_lang_call(cx,
58 langcall(cx, None, "", ExchangeFreeFnLangItem),
59 [PointerCast(cx, v, Type::i8p(ccx)), C_uint(ccx, size as uint), C_uint(ccx, align as uint)],
60 Some(expr::Ignore)).bcx
63 pub fn trans_exchange_free_ty<'a>(bcx: &'a Block<'a>, ptr: ValueRef,
64 content_ty: ty::t) -> &'a Block<'a> {
65 let sizing_type = sizing_type_of(bcx.ccx(), content_ty);
66 let content_size = llsize_of_alloc(bcx.ccx(), sizing_type);
68 // `Box<ZeroSizeType>` does not allocate.
69 if content_size != 0 {
70 let content_align = llalign_of_min(bcx.ccx(), sizing_type);
71 trans_exchange_free(bcx, ptr, content_size, content_align)
77 pub fn take_ty<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
79 // NB: v is an *alias* of type t here, not a direct value.
80 let _icx = push_ctxt("take_ty");
81 match ty::get(t).sty {
82 ty::ty_box(_) => incr_refcnt_of_boxed(bcx, v),
83 _ if ty::type_is_structural(t)
84 && ty::type_needs_drop(bcx.tcx(), t) => {
85 iter_structural_ty(bcx, v, t, take_ty)
91 pub fn get_drop_glue_type(ccx: &CrateContext, t: ty::t) -> ty::t {
93 if !ty::type_needs_drop(tcx, t) {
96 match ty::get(t).sty {
97 ty::ty_box(typ) if !ty::type_needs_drop(tcx, typ) =>
98 ty::mk_box(tcx, ty::mk_i8()),
100 ty::ty_uniq(typ) if !ty::type_needs_drop(tcx, typ) => {
101 match ty::get(typ).sty {
102 ty::ty_vec(_, None) | ty::ty_str => t,
104 let llty = sizing_type_of(ccx, typ);
105 // `Box<ZeroSizeType>` does not allocate.
106 if llsize_of_alloc(ccx, llty) == 0 {
109 ty::mk_uniq(tcx, ty::mk_i8())
118 pub fn drop_ty<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
120 // NB: v is an *alias* of type t here, not a direct value.
121 let _icx = push_ctxt("drop_ty");
123 if ty::type_needs_drop(bcx.tcx(), t) {
124 let glue = get_drop_glue(ccx, t);
125 let glue_type = get_drop_glue_type(ccx, t);
126 let ptr = if glue_type != t {
127 PointerCast(bcx, v, type_of(ccx, glue_type).ptr_to())
131 Call(bcx, glue, [ptr], []);
136 pub fn drop_ty_immediate<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
138 let _icx = push_ctxt("drop_ty_immediate");
139 let vp = alloca(bcx, type_of(bcx.ccx(), t), "");
144 pub fn get_drop_glue(ccx: &CrateContext, t: ty::t) -> ValueRef {
145 let t = get_drop_glue_type(ccx, t);
146 match ccx.drop_glues.borrow().find(&t) {
147 Some(&glue) => return glue,
151 let llfnty = Type::glue_fn(ccx, type_of(ccx, t).ptr_to());
152 let glue = declare_generic_glue(ccx, t, llfnty, "drop");
154 ccx.drop_glues.borrow_mut().insert(t, glue);
156 make_generic_glue(ccx, t, glue, make_drop_glue, "drop");
161 pub fn lazily_emit_visit_glue(ccx: &CrateContext, ti: &tydesc_info) -> ValueRef {
162 let _icx = push_ctxt("lazily_emit_visit_glue");
164 let llfnty = Type::glue_fn(ccx, type_of(ccx, ti.ty).ptr_to());
166 match ti.visit_glue.get() {
167 Some(visit_glue) => visit_glue,
169 debug!("+++ lazily_emit_tydesc_glue VISIT {}", ppaux::ty_to_str(ccx.tcx(), ti.ty));
170 let glue_fn = declare_generic_glue(ccx, ti.ty, llfnty, "visit");
171 ti.visit_glue.set(Some(glue_fn));
172 make_generic_glue(ccx, ti.ty, glue_fn, make_visit_glue, "visit");
173 debug!("--- lazily_emit_tydesc_glue VISIT {}", ppaux::ty_to_str(ccx.tcx(), ti.ty));
179 // See [Note-arg-mode]
180 pub fn call_visit_glue(bcx: &Block, v: ValueRef, tydesc: ValueRef,
181 static_ti: Option<&tydesc_info>) {
182 let _icx = push_ctxt("call_tydesc_glue_full");
184 // NB: Don't short-circuit even if this block is unreachable because
185 // GC-based cleanup needs to the see that the roots are live.
186 if bcx.unreachable.get() && !ccx.sess().no_landing_pads() { return; }
188 let static_glue_fn = static_ti.map(|sti| lazily_emit_visit_glue(ccx, sti));
190 // When static type info is available, avoid casting to a generic pointer.
191 let llrawptr = if static_glue_fn.is_none() {
192 PointerCast(bcx, v, Type::i8p(ccx))
198 match static_glue_fn {
200 // Select out the glue function to call from the tydesc
201 let llfnptr = GEPi(bcx, tydesc, [0u, abi::tydesc_field_visit_glue]);
208 Call(bcx, llfn, [llrawptr], []);
211 fn make_visit_glue<'a>(bcx: &'a Block<'a>, v: ValueRef, t: ty::t)
213 let _icx = push_ctxt("make_visit_glue");
215 let (visitor_trait, object_ty) = match ty::visitor_object_ty(bcx.tcx(),
219 bcx.tcx().sess.fatal(s.as_slice());
222 let v = PointerCast(bcx, v, type_of(bcx.ccx(), object_ty).ptr_to());
223 bcx = reflect::emit_calls_to_trait_visit_ty(bcx, t, v, visitor_trait.def_id);
227 fn trans_struct_drop_flag<'a>(bcx: &'a Block<'a>,
230 dtor_did: ast::DefId,
231 class_did: ast::DefId,
234 let repr = adt::represent_type(bcx.ccx(), t);
235 let drop_flag = adt::trans_drop_flag_ptr(bcx, &*repr, v0);
236 with_cond(bcx, IsNotNull(bcx, Load(bcx, drop_flag)), |cx| {
237 trans_struct_drop(cx, t, v0, dtor_did, class_did, substs)
241 fn trans_struct_drop<'a>(bcx: &'a Block<'a>,
244 dtor_did: ast::DefId,
245 class_did: ast::DefId,
248 let repr = adt::represent_type(bcx.ccx(), t);
250 // Find and call the actual destructor
251 let dtor_addr = get_res_dtor(bcx.ccx(), dtor_did, t,
254 // The second argument is the "self" argument for drop
255 let params = unsafe {
256 let ty = Type::from_ref(llvm::LLVMTypeOf(dtor_addr));
257 ty.element_type().func_params()
260 // Class dtors have no explicit args, so the params should
261 // just consist of the environment (self)
262 assert_eq!(params.len(), 1);
264 // Be sure to put all of the fields into a scope so we can use an invoke
265 // instruction to call the user destructor but still call the field
266 // destructors if the user destructor fails.
267 let field_scope = bcx.fcx.push_custom_cleanup_scope();
269 let self_arg = PointerCast(bcx, v0, *params.get(0));
270 let args = vec!(self_arg);
272 // Add all the fields as a value which needs to be cleaned at the end of
274 let field_tys = ty::struct_fields(bcx.tcx(), class_did, substs);
275 for (i, fld) in field_tys.iter().enumerate() {
276 let llfld_a = adt::trans_field_ptr(bcx, &*repr, v0, 0, i);
277 bcx.fcx.schedule_drop_mem(cleanup::CustomScope(field_scope),
282 let dtor_ty = ty::mk_ctor_fn(bcx.tcx(), ast::DUMMY_NODE_ID,
283 [get_drop_glue_type(bcx.ccx(), t)], ty::mk_nil());
284 let (_, bcx) = invoke(bcx, dtor_addr, args, dtor_ty, None);
286 bcx.fcx.pop_and_trans_custom_cleanup_scope(bcx, field_scope)
289 fn make_drop_glue<'a>(bcx: &'a Block<'a>, v0: ValueRef, t: ty::t) -> &'a Block<'a> {
290 // NB: v0 is an *alias* of type t here, not a direct value.
291 let _icx = push_ctxt("make_drop_glue");
292 match ty::get(t).sty {
293 ty::ty_box(body_ty) => {
294 decr_refcnt_maybe_free(bcx, v0, body_ty)
296 ty::ty_uniq(content_ty) => {
297 let llbox = Load(bcx, v0);
298 let not_null = IsNotNull(bcx, llbox);
299 match ty::get(content_ty).sty {
300 ty::ty_vec(mt, None) => {
301 with_cond(bcx, not_null, |bcx| {
302 let bcx = tvec::make_drop_glue_unboxed(bcx, llbox, mt.ty);
303 // FIXME: #13994: the old `Box<[T]>` will not support sized deallocation
304 trans_exchange_free(bcx, llbox, 0, 8)
308 with_cond(bcx, not_null, |bcx| {
309 let unit_ty = ty::sequence_element_type(bcx.tcx(), t);
310 let bcx = tvec::make_drop_glue_unboxed(bcx, llbox, unit_ty);
311 // FIXME: #13994: the old `Box<str>` will not support sized deallocation
312 trans_exchange_free(bcx, llbox, 0, 8)
316 with_cond(bcx, not_null, |bcx| {
317 let bcx = drop_ty(bcx, llbox, content_ty);
318 trans_exchange_free_ty(bcx, llbox, content_ty)
323 ty::ty_struct(did, ref substs) => {
325 match ty::ty_dtor(tcx, did) {
326 ty::TraitDtor(dtor, true) => {
327 trans_struct_drop_flag(bcx, t, v0, dtor, did, substs)
329 ty::TraitDtor(dtor, false) => {
330 trans_struct_drop(bcx, t, v0, dtor, did, substs)
333 // No dtor? Just the default case
334 iter_structural_ty(bcx, v0, t, drop_ty)
338 ty::ty_trait(box ty::TyTrait { store: ty::UniqTraitStore, .. }) => {
339 let lluniquevalue = GEPi(bcx, v0, [0, abi::trt_field_box]);
340 // Only drop the value when it is non-null
341 with_cond(bcx, IsNotNull(bcx, Load(bcx, lluniquevalue)), |bcx| {
342 let dtor_ptr = Load(bcx, GEPi(bcx, v0, [0, abi::trt_field_vtable]));
343 let dtor = Load(bcx, dtor_ptr);
344 Call(bcx, dtor, [PointerCast(bcx, lluniquevalue, Type::i8p(bcx.ccx()))], []);
348 ty::ty_closure(ref f) if f.store == ty::UniqTraitStore => {
349 let box_cell_v = GEPi(bcx, v0, [0u, abi::fn_field_box]);
350 let env = Load(bcx, box_cell_v);
351 let env_ptr_ty = Type::at_box(bcx.ccx(), Type::i8(bcx.ccx())).ptr_to();
352 let env = PointerCast(bcx, env, env_ptr_ty);
353 with_cond(bcx, IsNotNull(bcx, env), |bcx| {
354 let dtor_ptr = GEPi(bcx, env, [0u, abi::box_field_tydesc]);
355 let dtor = Load(bcx, dtor_ptr);
356 let cdata = GEPi(bcx, env, [0u, abi::box_field_body]);
357 Call(bcx, dtor, [PointerCast(bcx, cdata, Type::i8p(bcx.ccx()))], []);
359 // Free the environment itself
360 // FIXME: #13994: pass align and size here
361 trans_exchange_free(bcx, env, 0, 8)
365 if ty::type_needs_drop(bcx.tcx(), t) &&
366 ty::type_is_structural(t) {
367 iter_structural_ty(bcx, v0, t, drop_ty)
375 fn decr_refcnt_maybe_free<'a>(bcx: &'a Block<'a>,
376 box_ptr_ptr: ValueRef,
377 t: ty::t) -> &'a Block<'a> {
378 let _icx = push_ctxt("decr_refcnt_maybe_free");
382 let decr_bcx = fcx.new_temp_block("decr");
383 let free_bcx = fcx.new_temp_block("free");
384 let next_bcx = fcx.new_temp_block("next");
386 let box_ptr = Load(bcx, box_ptr_ptr);
387 let llnotnull = IsNotNull(bcx, box_ptr);
388 CondBr(bcx, llnotnull, decr_bcx.llbb, next_bcx.llbb);
390 let rc_ptr = GEPi(decr_bcx, box_ptr, [0u, abi::box_field_refcnt]);
391 let rc = Sub(decr_bcx, Load(decr_bcx, rc_ptr), C_int(ccx, 1));
392 Store(decr_bcx, rc, rc_ptr);
393 CondBr(decr_bcx, IsNull(decr_bcx, rc), free_bcx.llbb, next_bcx.llbb);
395 let v = Load(free_bcx, box_ptr_ptr);
396 let body = GEPi(free_bcx, v, [0u, abi::box_field_body]);
397 let free_bcx = drop_ty(free_bcx, body, t);
398 let free_bcx = trans_free(free_bcx, v);
399 Br(free_bcx, next_bcx.llbb);
404 fn incr_refcnt_of_boxed<'a>(bcx: &'a Block<'a>,
405 box_ptr_ptr: ValueRef) -> &'a Block<'a> {
406 let _icx = push_ctxt("incr_refcnt_of_boxed");
408 let box_ptr = Load(bcx, box_ptr_ptr);
409 let rc_ptr = GEPi(bcx, box_ptr, [0u, abi::box_field_refcnt]);
410 let rc = Load(bcx, rc_ptr);
411 let rc = Add(bcx, rc, C_int(ccx, 1));
412 Store(bcx, rc, rc_ptr);
417 // Generates the declaration for (but doesn't emit) a type descriptor.
418 pub fn declare_tydesc(ccx: &CrateContext, t: ty::t) -> tydesc_info {
419 // If emit_tydescs already ran, then we shouldn't be creating any new
421 assert!(!ccx.finished_tydescs.get());
423 let llty = type_of(ccx, t);
425 if ccx.sess().count_type_sizes() {
426 println!("{}\t{}", llsize_of_real(ccx, llty),
427 ppaux::ty_to_str(ccx.tcx(), t));
430 let llsize = llsize_of(ccx, llty);
431 let llalign = llalign_of(ccx, llty);
432 let name = mangle_internal_name_by_type_and_seq(ccx, t, "tydesc");
433 debug!("+++ declare_tydesc {} {}", ppaux::ty_to_str(ccx.tcx(), t), name);
434 let gvar = name.as_slice().with_c_str(|buf| {
436 llvm::LLVMAddGlobal(ccx.llmod, ccx.tydesc_type().to_ref(), buf)
439 note_unique_llvm_symbol(ccx, name);
441 let ty_name = token::intern_and_get_ident(
442 ppaux::ty_to_str(ccx.tcx(), t).as_slice());
443 let ty_name = C_str_slice(ccx, ty_name);
445 debug!("--- declare_tydesc {}", ppaux::ty_to_str(ccx.tcx(), t));
452 visit_glue: Cell::new(None),
456 fn declare_generic_glue(ccx: &CrateContext, t: ty::t, llfnty: Type,
457 name: &str) -> ValueRef {
458 let _icx = push_ctxt("declare_generic_glue");
459 let fn_nm = mangle_internal_name_by_type_and_seq(
462 format!("glue_{}", name).as_slice());
463 debug!("{} is for type {}", fn_nm, ppaux::ty_to_str(ccx.tcx(), t));
464 let llfn = decl_cdecl_fn(ccx.llmod, fn_nm.as_slice(), llfnty, ty::mk_nil());
465 note_unique_llvm_symbol(ccx, fn_nm);
469 fn make_generic_glue(ccx: &CrateContext,
472 helper: <'a> |&'a Block<'a>, ValueRef, ty::t|
476 let _icx = push_ctxt("make_generic_glue");
477 let glue_name = format_strbuf!("glue {} {}",
479 ty_to_short_str(ccx.tcx(), t));
480 let _s = StatRecorder::new(ccx, glue_name);
482 let arena = TypedArena::new();
483 let fcx = new_fn_ctxt(ccx, llfn, -1, false, ty::mk_nil(), None, None, &arena);
485 init_function(&fcx, false, ty::mk_nil());
487 lib::llvm::SetLinkage(llfn, lib::llvm::InternalLinkage);
488 ccx.stats.n_glues_created.set(ccx.stats.n_glues_created.get() + 1u);
489 // All glue functions take values passed *by alias*; this is a
490 // requirement since in many contexts glue is invoked indirectly and
491 // the caller has no idea if it's dealing with something that can be
494 // llfn is expected be declared to take a parameter of the appropriate
495 // type, so we don't need to explicitly cast the function parameter.
497 let bcx = fcx.entry_bcx.borrow().clone().unwrap();
498 let llrawptr0 = unsafe { llvm::LLVMGetParam(llfn, fcx.arg_pos(0) as c_uint) };
499 let bcx = helper(bcx, llrawptr0, t);
500 finish_fn(&fcx, bcx);
505 pub fn emit_tydescs(ccx: &CrateContext) {
506 let _icx = push_ctxt("emit_tydescs");
507 // As of this point, allow no more tydescs to be created.
508 ccx.finished_tydescs.set(true);
509 let glue_fn_ty = Type::generic_glue_fn(ccx).ptr_to();
510 for (_, ti) in ccx.tydescs.borrow().iter() {
511 // Each of the glue functions needs to be cast to a generic type
512 // before being put into the tydesc because we only have a singleton
513 // tydesc type. Then we'll recast each function to its real type when
515 let drop_glue = unsafe {
516 llvm::LLVMConstPointerCast(get_drop_glue(ccx, ti.ty), glue_fn_ty.to_ref())
518 ccx.stats.n_real_glues.set(ccx.stats.n_real_glues.get() + 1);
520 match ti.visit_glue.get() {
522 ccx.stats.n_null_glues.set(ccx.stats.n_null_glues.get() +
528 ccx.stats.n_real_glues.set(ccx.stats.n_real_glues.get() +
530 llvm::LLVMConstPointerCast(v, glue_fn_ty.to_ref())
535 let tydesc = C_named_struct(ccx.tydesc_type(),
538 drop_glue, // drop_glue
539 visit_glue, // visit_glue
543 let gvar = ti.tydesc;
544 llvm::LLVMSetInitializer(gvar, tydesc);
545 llvm::LLVMSetGlobalConstant(gvar, True);
546 lib::llvm::SetLinkage(gvar, lib::llvm::InternalLinkage);