2 use crate::build::scope::DropKind;
3 use crate::thir::cx::Cx;
4 use crate::thir::{BindingMode, LintLevel, PatKind};
5 use rustc_attr::{self as attr, UnwindAttr};
6 use rustc_errors::ErrorReported;
8 use rustc_hir::def_id::{DefId, LocalDefId};
9 use rustc_hir::lang_items::LangItem;
10 use rustc_hir::{GeneratorKind, HirIdMap, Node};
11 use rustc_index::vec::{Idx, IndexVec};
12 use rustc_infer::infer::TyCtxtInferExt;
13 use rustc_middle::middle::region;
14 use rustc_middle::mir::*;
15 use rustc_middle::ty::subst::Subst;
16 use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable};
17 use rustc_span::symbol::kw;
19 use rustc_target::spec::abi::Abi;
20 use rustc_target::spec::PanicStrategy;
24 crate fn mir_built<'tcx>(
26 def: ty::WithOptConstParam<LocalDefId>,
27 ) -> &'tcx rustc_data_structures::steal::Steal<Body<'tcx>> {
28 if let Some(def) = def.try_upgrade(tcx) {
29 return tcx.mir_built(def);
32 let mut body = mir_build(tcx, def);
33 if def.const_param_did.is_some() {
34 assert!(matches!(body.source.instance, ty::InstanceDef::Item(_)));
35 body.source = MirSource::from_instance(ty::InstanceDef::Item(def.to_global()));
38 tcx.alloc_steal_mir(body)
41 /// Construct the MIR for a given `DefId`.
42 fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
43 let id = tcx.hir().local_def_id_to_hir_id(def.did);
45 // Figure out what primary body this item has.
46 let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
47 Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) => {
48 (*body_id, decl.output.span(), None)
50 Node::Item(hir::Item {
51 kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
55 | Node::ImplItem(hir::ImplItem {
56 kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id),
60 | Node::TraitItem(hir::TraitItem {
61 kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)),
65 // Use the `Span` of the `Item/ImplItem/TraitItem` as the body span,
66 // since the def span of a function does not include the body
67 (*body_id, decl.output.span(), Some(*span))
69 Node::Item(hir::Item {
70 kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id),
73 | Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
74 | Node::TraitItem(hir::TraitItem {
75 kind: hir::TraitItemKind::Const(ty, Some(body_id)),
77 }) => (*body_id, ty.span, None),
78 Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
79 (*body, tcx.hir().span(*hir_id), None)
82 _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did),
85 // If we don't have a specialized span for the body, just use the
87 let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
89 tcx.infer_ctxt().enter(|infcx| {
90 let cx = Cx::new(&infcx, def, id);
91 let body = if let Some(ErrorReported) = cx.typeck_results().tainted_by_errors {
92 build::construct_error(cx, body_id)
93 } else if cx.body_owner_kind.is_fn_or_closure() {
94 // fetch the fully liberated fn signature (that is, all bound
95 // types/lifetimes replaced)
96 let fn_sig = cx.typeck_results().liberated_fn_sigs()[id];
97 let fn_def_id = tcx.hir().local_def_id(id);
99 let safety = match fn_sig.unsafety {
100 hir::Unsafety::Normal => Safety::Safe,
101 hir::Unsafety::Unsafe => Safety::FnUnsafe,
104 let body = tcx.hir().body(body_id);
105 let ty = tcx.type_of(fn_def_id);
106 let mut abi = fn_sig.abi;
107 let implicit_argument = match ty.kind() {
109 // HACK(eddyb) Avoid having RustCall on closures,
110 // as it adds unnecessary (and wrong) auto-tupling.
112 vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
114 ty::Generator(..) => {
115 let gen_ty = tcx.typeck_body(body_id).node_type(id);
117 // The resume argument may be missing, in that case we need to provide it here.
118 // It will always be `()` in this case.
119 if body.params.is_empty() {
121 ArgInfo(gen_ty, None, None, None),
122 ArgInfo(tcx.mk_unit(), None, None, None),
125 vec![ArgInfo(gen_ty, None, None, None)]
131 let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
132 let owner_id = tcx.hir().body_owner(body_id);
135 if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
136 opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
137 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
138 match fn_decl.implicit_self {
139 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
140 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
141 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
142 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
153 // C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
154 // (as it's created inside the body itself, not passed in from outside).
155 let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
156 let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span));
158 tcx.type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()])
160 fn_sig.inputs()[index]
163 ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
166 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
168 let (yield_ty, return_ty) = if body.generator_kind.is_some() {
169 let gen_ty = tcx.typeck_body(body_id).node_type(id);
170 let gen_sig = match gen_ty.kind() {
171 ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
172 _ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
174 (Some(gen_sig.yield_ty), gen_sig.return_ty)
176 (None, fn_sig.output())
179 let mut mir = build::construct_fn(
190 mir.yield_ty = yield_ty;
193 // Get the revealed type of this const. This is *not* the adjusted
194 // type of its body, which may be a subtype of this type. For
198 // static X: fn(&'static ()) = foo;
200 // The adjusted type of the body of X is `for<'a> fn(&'a ())` which
201 // is not the same as the type of X. We need the type of the return
202 // place to be the type of the constant because NLL typeck will
205 let return_ty = cx.typeck_results().node_type(id);
207 build::construct_const(cx, body_id, return_ty, return_ty_span)
210 lints::check(tcx, &body);
212 // The borrow checker will replace all the regions here with its own
213 // inference variables. There's no point having non-erased regions here.
214 // The exception is `body.user_type_annotations`, which is used unmodified
215 // by borrow checking.
217 !(body.local_decls.has_free_regions()
218 || body.basic_blocks().has_free_regions()
219 || body.var_debug_info.has_free_regions()
220 || body.yield_ty.has_free_regions()),
221 "Unexpected free regions in MIR: {:?}",
229 ///////////////////////////////////////////////////////////////////////////
230 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
232 fn liberated_closure_env_ty(
234 closure_expr_id: hir::HirId,
235 body_id: hir::BodyId,
237 let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id);
239 let (closure_def_id, closure_substs) = match *closure_ty.kind() {
240 ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
241 _ => bug!("closure expr does not have closure type: {:?}", closure_ty),
244 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
245 tcx.erase_late_bound_regions(closure_env_ty)
248 #[derive(Debug, PartialEq, Eq)]
250 /// Evaluation is currently within a statement.
252 /// Examples include:
254 /// 2. `let _ = EXPR;`
255 /// 3. `let x = EXPR;`
257 /// If true, then statement discards result from evaluating
258 /// the expression (such as examples 1 and 2 above).
259 ignores_expr_result: bool,
262 /// Evaluation is currently within the tail expression of a block.
264 /// Example: `{ STMT_1; STMT_2; EXPR }`
266 /// If true, then the surrounding context of the block ignores
267 /// the result of evaluating the block's tail expression.
269 /// Example: `let _ = { STMT_1; EXPR };`
270 tail_result_is_ignored: bool,
272 /// `Span` of the tail expression.
276 /// Generic mark meaning that the block occurred as a subexpression
277 /// where the result might be used.
279 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
284 fn is_tail_expr(&self) -> bool {
286 BlockFrame::TailExpr { .. } => true,
288 BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
291 fn is_statement(&self) -> bool {
293 BlockFrame::Statement { .. } => true,
295 BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
301 struct BlockContext(Vec<BlockFrame>);
303 struct Builder<'a, 'tcx> {
310 generator_kind: Option<GeneratorKind>,
312 /// The current set of scopes, updated as we traverse;
313 /// see the `scope` module for more details.
314 scopes: scope::Scopes<'tcx>,
316 /// The block-context: each time we build the code within an thir::Block,
317 /// we push a frame here tracking whether we are building a statement or
318 /// if we are pushing the tail expression of the block. This is used to
319 /// embed information in generated temps about whether they were created
320 /// for a block tail expression or not.
322 /// It would be great if we could fold this into `self.scopes`
323 /// somehow, but right now I think that is very tightly tied to
324 /// the code generation in ways that we cannot (or should not)
325 /// start just throwing new entries onto that vector in order to
326 /// distinguish the context of EXPR1 from the context of EXPR2 in
327 /// `{ STMTS; EXPR1 } + EXPR2`.
328 block_context: BlockContext,
330 /// The current unsafe block in scope, even if it is hidden by
331 /// a `PushUnsafeBlock`.
332 unpushed_unsafe: Safety,
334 /// The number of `push_unsafe_block` levels in scope.
335 push_unsafe_count: usize,
337 /// The vector of all scopes that we have created thus far;
338 /// we track this for debuginfo later.
339 source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
340 source_scope: SourceScope,
342 /// The guard-context: each time we build the guard expression for
343 /// a match arm, we push onto this stack, and then pop when we
344 /// finish building it.
345 guard_context: Vec<GuardFrame>,
347 /// Maps `HirId`s of variable bindings to the `Local`s created for them.
348 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
349 var_indices: HirIdMap<LocalsForNode>,
350 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
351 canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
352 upvar_mutbls: Vec<Mutability>,
353 unit_temp: Option<Place<'tcx>>,
355 var_debug_info: Vec<VarDebugInfo<'tcx>>,
358 impl<'a, 'tcx> Builder<'a, 'tcx> {
359 fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
360 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
363 fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
364 self.var_indices[&id].local_id(for_guard)
372 fn push(&mut self, bf: BlockFrame) {
375 fn pop(&mut self) -> Option<BlockFrame> {
379 /// Traverses the frames on the `BlockContext`, searching for either
380 /// the first block-tail expression frame with no intervening
383 /// Notably, this skips over `SubExpr` frames; this method is
384 /// meant to be used in the context of understanding the
385 /// relationship of a temp (created within some complicated
386 /// expression) with its containing expression, and whether the
387 /// value of that *containing expression* (not the temp!) is
389 fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
390 for bf in self.0.iter().rev() {
392 BlockFrame::SubExpr => continue,
393 BlockFrame::Statement { .. } => break,
394 &BlockFrame::TailExpr { tail_result_is_ignored, span } => {
395 return Some(BlockTailInfo { tail_result_is_ignored, span });
403 /// Looks at the topmost frame on the BlockContext and reports
404 /// whether its one that would discard a block tail result.
406 /// Unlike `currently_within_ignored_tail_expression`, this does
407 /// *not* skip over `SubExpr` frames: here, we want to know
408 /// whether the block result itself is discarded.
409 fn currently_ignores_tail_results(&self) -> bool {
410 match self.0.last() {
411 // no context: conservatively assume result is read
414 // sub-expression: block result feeds into some computation
415 Some(BlockFrame::SubExpr) => false,
417 // otherwise: use accumulated is_ignored state.
419 BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. }
420 | BlockFrame::Statement { ignores_expr_result: ignored },
428 /// In the usual case, a `HirId` for an identifier maps to at most
429 /// one `Local` declaration.
432 /// The exceptional case is identifiers in a match arm's pattern
433 /// that are referenced in a guard of that match arm. For these,
434 /// we have `2` Locals.
436 /// * `for_arm_body` is the Local used in the arm body (which is
437 /// just like the `One` case above),
439 /// * `ref_for_guard` is the Local used in the arm's guard (which
440 /// is a reference to a temp that is an alias of
442 ForGuard { ref_for_guard: Local, for_arm_body: Local },
446 struct GuardFrameLocal {
450 impl GuardFrameLocal {
451 fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
452 GuardFrameLocal { id }
458 /// These are the id's of names that are bound by patterns of the
459 /// arm of *this* guard.
461 /// (Frames higher up the stack will have the id's bound in arms
462 /// further out, such as in a case like:
465 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
468 /// here, when building for FIXME.
469 locals: Vec<GuardFrameLocal>,
472 /// `ForGuard` indicates whether we are talking about:
473 /// 1. The variable for use outside of guard expressions, or
474 /// 2. The temp that holds reference to (1.), which is actually what the
475 /// guard expressions see.
476 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
483 fn local_id(&self, for_guard: ForGuard) -> Local {
484 match (self, for_guard) {
485 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard)
487 &LocalsForNode::ForGuard { ref_for_guard: local_id, .. },
488 ForGuard::RefWithinGuard,
490 | (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => {
494 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => {
495 bug!("anything with one local should never be within a guard.")
502 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
505 rustc_index::newtype_index! {
506 struct ScopeId { .. }
509 ///////////////////////////////////////////////////////////////////////////
510 /// The `BlockAnd` "monad" packages up the new basic block along with a
511 /// produced value (sometimes just unit, of course). The `unpack!`
512 /// macro (and methods below) makes working with `BlockAnd` much more
515 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
516 struct BlockAnd<T>(BasicBlock, T);
518 trait BlockAndExtension {
519 fn and<T>(self, v: T) -> BlockAnd<T>;
520 fn unit(self) -> BlockAnd<()>;
523 impl BlockAndExtension for BasicBlock {
524 fn and<T>(self, v: T) -> BlockAnd<T> {
528 fn unit(self) -> BlockAnd<()> {
533 /// Update a block pointer and return the value.
534 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
535 macro_rules! unpack {
536 ($x:ident = $c:expr) => {{
537 let BlockAnd(b, v) = $c;
543 let BlockAnd(b, ()) = $c;
548 fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: LocalDefId, _abi: Abi) -> bool {
549 // Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
550 let attrs = &tcx.get_attrs(fn_def_id.to_def_id());
551 let unwind_attr = attr::find_unwind_attr(&tcx.sess, attrs);
553 // We never unwind, so it's not relevant to stop an unwind.
554 if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
558 // This is a special case: some functions have a C abi but are meant to
559 // unwind anyway. Don't stop them.
561 None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
562 Some(UnwindAttr::Allowed) => false,
563 Some(UnwindAttr::Aborts) => true,
567 ///////////////////////////////////////////////////////////////////////////
568 /// the main entry point for building MIR for a function
570 struct ArgInfo<'tcx>(
573 Option<&'tcx hir::Param<'tcx>>,
574 Option<ImplicitSelfKind>,
577 fn construct_fn<'a, 'tcx, A>(
584 return_ty_span: Span,
585 body: &'tcx hir::Body<'tcx>,
586 span_with_body: Span,
589 A: Iterator<Item = ArgInfo<'tcx>>,
591 let arguments: Vec<_> = arguments.collect();
594 let tcx_hir = tcx.hir();
595 let span = tcx_hir.span(fn_id);
597 let fn_def_id = tcx_hir.local_def_id(fn_id);
599 let mut builder = Builder::new(
601 fn_def_id.to_def_id(),
610 let call_site_scope =
611 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::CallSite };
613 region::Scope { id: body.value.hir_id.local_id, data: region::ScopeData::Arguments };
614 let source_info = builder.source_info(span);
615 let call_site_s = (call_site_scope, source_info);
616 unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
617 let arg_scope_s = (arg_scope, source_info);
618 // Attribute epilogue to function's closing brace
619 let fn_end = span_with_body.shrink_to_hi();
620 let return_block = unpack!(builder.in_breakable_scope(
622 Place::return_place(),
623 Some(call_site_scope),
626 Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
627 builder.args_and_body(
629 fn_def_id.to_def_id(),
637 let source_info = builder.source_info(fn_end);
638 builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
639 let should_abort = should_abort_on_panic(tcx, fn_def_id, abi);
640 builder.build_drop_trees(should_abort);
641 builder.unschedule_return_place_drop();
645 let spread_arg = if abi == Abi::RustCall {
646 // RustCall pseudo-ABI untuples the last argument.
647 Some(Local::new(arguments.len()))
651 debug!("fn_id {:?} has attrs {:?}", fn_def_id, tcx.get_attrs(fn_def_id.to_def_id()));
653 let mut body = builder.finish();
654 body.spread_arg = spread_arg;
658 fn construct_const<'a, 'tcx>(
660 body_id: hir::BodyId,
665 let owner_id = tcx.hir().body_owner(body_id);
666 let def_id = tcx.hir().local_def_id(owner_id);
667 let span = tcx.hir().span(owner_id);
669 Builder::new(hir, def_id.to_def_id(), span, 0, Safety::Safe, const_ty, const_ty_span, None);
671 let mut block = START_BLOCK;
672 let ast_expr = &tcx.hir().body(body_id).value;
673 let expr = builder.hir.mirror(ast_expr);
674 // We don't provide a scope because we can't unwind in constants, so won't
675 // need to drop the return place.
676 unpack!(block = builder.into_expr(Place::return_place(), None, block, expr));
678 let source_info = builder.source_info(span);
679 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
681 builder.build_drop_trees(false);
686 /// Construct MIR for a item that has had errors in type checking.
688 /// This is required because we may still want to run MIR passes on an item
689 /// with type errors, but normal MIR construction can't handle that in general.
690 fn construct_error<'a, 'tcx>(hir: Cx<'a, 'tcx>, body_id: hir::BodyId) -> Body<'tcx> {
692 let owner_id = tcx.hir().body_owner(body_id);
693 let def_id = tcx.hir().local_def_id(owner_id);
694 let span = tcx.hir().span(owner_id);
695 let ty = tcx.ty_error();
696 let num_params = match hir.body_owner_kind {
697 hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len(),
698 hir::BodyOwnerKind::Closure => {
699 if tcx.hir().body(body_id).generator_kind().is_some() {
700 // Generators have an implicit `self` parameter *and* a possibly
701 // implicit resume parameter.
704 // The implicit self parameter adds another local in MIR.
705 1 + tcx.hir().fn_decl_by_hir_id(owner_id).unwrap().inputs.len()
708 hir::BodyOwnerKind::Const => 0,
709 hir::BodyOwnerKind::Static(_) => 0,
712 Builder::new(hir, def_id.to_def_id(), span, num_params, Safety::Safe, ty, span, None);
713 let source_info = builder.source_info(span);
714 // Some MIR passes will expect the number of parameters to match the
715 // function declaration.
716 for _ in 0..num_params {
717 builder.local_decls.push(LocalDecl::with_source_info(ty, source_info));
719 builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
720 let mut body = builder.finish();
721 if tcx.hir().body(body_id).generator_kind.is_some() {
722 body.yield_ty = Some(ty);
727 impl<'a, 'tcx> Builder<'a, 'tcx> {
736 generator_kind: Option<GeneratorKind>,
737 ) -> Builder<'a, 'tcx> {
738 let lint_level = LintLevel::Explicit(hir.root_lint_level);
739 let mut builder = Builder {
742 cfg: CFG { basic_blocks: IndexVec::new() },
746 scopes: scope::Scopes::new(),
747 block_context: BlockContext::new(),
748 source_scopes: IndexVec::new(),
749 source_scope: OUTERMOST_SOURCE_SCOPE,
750 guard_context: vec![],
751 push_unsafe_count: 0,
752 unpushed_unsafe: safety,
753 local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1),
754 canonical_user_type_annotations: IndexVec::new(),
755 upvar_mutbls: vec![],
756 var_indices: Default::default(),
758 var_debug_info: vec![],
761 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
763 builder.new_source_scope(span, lint_level, Some(safety)),
764 OUTERMOST_SOURCE_SCOPE
766 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
771 fn finish(self) -> Body<'tcx> {
772 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
773 if block.terminator.is_none() {
774 span_bug!(self.fn_span, "no terminator on block {:?}", index);
779 MirSource::item(self.def_id),
780 self.cfg.basic_blocks,
783 self.canonical_user_type_annotations,
793 mut block: BasicBlock,
795 arguments: &[ArgInfo<'tcx>],
796 argument_scope: region::Scope,
797 ast_body: &'tcx hir::Expr<'tcx>,
799 // Allocate locals for the function arguments
800 for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
802 SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span));
803 let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info));
805 // If this is a simple binding pattern, give debuginfo a nice name.
806 if let Some(arg) = arg_opt {
807 if let Some(ident) = arg.pat.simple_ident() {
808 self.var_debug_info.push(VarDebugInfo {
811 place: arg_local.into(),
817 let tcx = self.hir.tcx();
818 let tcx_hir = tcx.hir();
819 let hir_typeck_results = self.hir.typeck_results();
821 // In analyze_closure() in upvar.rs we gathered a list of upvars used by a
822 // indexed closure and we stored in a map called closure_captures in TypeckResults
823 // with the closure's DefId. Here, we run through that vec of UpvarIds for
824 // the given closure and use the necessary information to create upvar
825 // debuginfo and to fill `self.upvar_mutbls`.
826 if let Some(upvars) = hir_typeck_results.closure_captures.get(&fn_def_id) {
827 let closure_env_arg = Local::new(1);
828 let mut closure_env_projs = vec![];
829 let mut closure_ty = self.local_decls[closure_env_arg].ty;
830 if let ty::Ref(_, ty, _) = closure_ty.kind() {
831 closure_env_projs.push(ProjectionElem::Deref);
834 let upvar_substs = match closure_ty.kind() {
835 ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
836 ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
837 _ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
839 let upvar_tys = upvar_substs.upvar_tys();
840 let upvars_with_tys = upvars.iter().zip(upvar_tys);
841 self.upvar_mutbls = upvars_with_tys
843 .map(|(i, ((&var_id, &upvar_id), ty))| {
844 let capture = hir_typeck_results.upvar_capture(upvar_id);
846 let mut mutability = Mutability::Not;
847 let mut name = kw::Invalid;
848 if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
849 if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
851 match hir_typeck_results
852 .extract_binding_mode(tcx.sess, pat.hir_id, pat.span)
854 Some(ty::BindByValue(hir::Mutability::Mut)) => {
855 mutability = Mutability::Mut;
857 Some(_) => mutability = Mutability::Not,
863 let mut projs = closure_env_projs.clone();
864 projs.push(ProjectionElem::Field(Field::new(i), ty));
866 ty::UpvarCapture::ByValue(_) => {}
867 ty::UpvarCapture::ByRef(..) => {
868 projs.push(ProjectionElem::Deref);
872 self.var_debug_info.push(VarDebugInfo {
874 source_info: SourceInfo::outermost(tcx_hir.span(var_id)),
876 local: closure_env_arg,
877 projection: tcx.intern_place_elems(&projs),
886 let mut scope = None;
887 // Bind the argument patterns
888 for (index, arg_info) in arguments.iter().enumerate() {
889 // Function arguments always get the first Local indices after the return place
890 let local = Local::new(index + 1);
891 let place = Place::from(local);
892 let &ArgInfo(_, opt_ty_info, arg_opt, ref self_binding) = arg_info;
894 // Make sure we drop (parts of) the argument even when not matched on.
896 arg_opt.as_ref().map_or(ast_body.span, |arg| arg.pat.span),
902 if let Some(arg) = arg_opt {
903 let pattern = self.hir.pattern_from_hir(&arg.pat);
904 let original_source_scope = self.source_scope;
905 let span = pattern.span;
906 self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span);
907 match *pattern.kind {
908 // Don't introduce extra copies for simple bindings
912 mode: BindingMode::ByValue,
916 self.local_decls[local].mutability = mutability;
917 self.local_decls[local].source_info.scope = self.source_scope;
918 self.local_decls[local].local_info = if let Some(kind) = self_binding {
919 Some(box LocalInfo::User(ClearCrossCrate::Set(
920 BindingForm::ImplicitSelf(*kind),
923 let binding_mode = ty::BindingMode::BindByValue(mutability);
924 Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
928 opt_match_place: Some((Some(place), span)),
933 self.var_indices.insert(var, LocalsForNode::One(local));
936 scope = self.declare_bindings(
940 matches::ArmHasGuard(false),
941 Some((Some(&place), span)),
943 unpack!(block = self.place_into_pattern(block, pattern, place, false));
946 self.source_scope = original_source_scope;
950 // Enter the argument pattern bindings source scope, if it exists.
951 if let Some(source_scope) = scope {
952 self.source_scope = source_scope;
955 let body = self.hir.mirror(ast_body);
957 region::Scope { id: ast_body.hir_id.local_id, data: region::ScopeData::CallSite };
958 self.into(Place::return_place(), Some(call_site), block, body)
961 fn set_correct_source_scope_for_arg(
963 arg_hir_id: hir::HirId,
964 original_source_scope: SourceScope,
967 let tcx = self.hir.tcx();
968 let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir.root_lint_level);
969 let parent_root = tcx.maybe_lint_level_root_bounded(
970 self.source_scopes[original_source_scope]
973 .assert_crate_local()
975 self.hir.root_lint_level,
977 if current_root != parent_root {
979 self.new_source_scope(pattern_span, LintLevel::Explicit(current_root), None);
983 fn get_unit_temp(&mut self) -> Place<'tcx> {
984 match self.unit_temp {
987 let ty = self.hir.unit_ty();
988 let fn_span = self.fn_span;
989 let tmp = self.temp(ty, fn_span);
990 self.unit_temp = Some(tmp);
997 ///////////////////////////////////////////////////////////////////////////
998 // Builder methods are broken up into modules, depending on what kind
999 // of thing is being lowered. Note that they use the `unpack` macro
1000 // above extensively.