1 // Copyright 2012-2014 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 use build::scope::{CachedBlock, DropKind};
15 use hair::{LintLevel, BindingMode, PatternKind};
18 use rustc::hir::def_id::{DefId, LocalDefId};
19 use rustc::middle::region;
21 use rustc::mir::visit::{MutVisitor, TyContext};
22 use rustc::ty::{self, Ty, TyCtxt};
23 use rustc::ty::subst::Substs;
24 use rustc::util::nodemap::NodeMap;
25 use rustc_target::spec::PanicStrategy;
26 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
30 use rustc_target::spec::abi::Abi;
32 use syntax::attr::{self, UnwindAttr};
33 use syntax::symbol::keywords;
35 use transform::MirSource;
38 /// Construct the MIR for a given def-id.
39 pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'tcx> {
40 let id = tcx.hir.as_local_node_id(def_id).unwrap();
42 // Figure out what primary body this item has.
43 let (body_id, return_ty_span) = match tcx.hir.get(id) {
44 Node::Variant(variant) =>
45 return create_constructor_shim(tcx, id, &variant.node.data),
46 Node::StructCtor(ctor) =>
47 return create_constructor_shim(tcx, id, ctor),
49 Node::Expr(hir::Expr { node: hir::ExprKind::Closure(_, decl, body_id, _, _), .. })
50 | Node::Item(hir::Item { node: hir::ItemKind::Fn(decl, _, _, body_id), .. })
53 node: hir::ImplItemKind::Method(hir::MethodSig { decl, .. }, body_id),
59 node: hir::TraitItemKind::Method(
60 hir::MethodSig { decl, .. },
61 hir::TraitMethod::Provided(body_id),
66 (*body_id, decl.output.span())
68 Node::Item(hir::Item { node: hir::ItemKind::Static(ty, _, body_id), .. })
69 | Node::Item(hir::Item { node: hir::ItemKind::Const(ty, body_id), .. })
70 | Node::ImplItem(hir::ImplItem { node: hir::ImplItemKind::Const(ty, body_id), .. })
72 hir::TraitItem { node: hir::TraitItemKind::Const(ty, Some(body_id)), .. }
76 Node::AnonConst(hir::AnonConst { body, id, .. }) => {
77 (*body, tcx.hir.span(*id))
80 _ => span_bug!(tcx.hir.span(id), "can't build MIR for {:?}", def_id),
83 tcx.infer_ctxt().enter(|infcx| {
84 let cx = Cx::new(&infcx, id);
85 let mut mir = if cx.tables().tainted_by_errors {
86 build::construct_error(cx, body_id)
87 } else if let hir::BodyOwnerKind::Fn = cx.body_owner_kind {
88 // fetch the fully liberated fn signature (that is, all bound
89 // types/lifetimes replaced)
90 let fn_hir_id = tcx.hir.node_to_hir_id(id);
91 let fn_sig = cx.tables().liberated_fn_sigs()[fn_hir_id].clone();
93 let ty = tcx.type_of(tcx.hir.local_def_id(id));
94 let mut abi = fn_sig.abi;
95 let implicit_argument = match ty.sty {
97 // HACK(eddyb) Avoid having RustCall on closures,
98 // as it adds unnecessary (and wrong) auto-tupling.
100 Some(ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None))
102 ty::Generator(..) => {
103 let gen_ty = tcx.body_tables(body_id).node_id_to_type(fn_hir_id);
104 Some(ArgInfo(gen_ty, None, None, None))
109 // FIXME: safety in closures
110 let safety = match fn_sig.unsafety {
111 hir::Unsafety::Normal => Safety::Safe,
112 hir::Unsafety::Unsafe => Safety::FnUnsafe,
115 let body = tcx.hir.body(body_id);
116 let explicit_arguments =
120 .map(|(index, arg)| {
121 let owner_id = tcx.hir.body_owner(body_id);
124 if let Some(ref fn_decl) = tcx.hir.fn_decl(owner_id) {
125 let ty_hir_id = fn_decl.inputs[index].hir_id;
126 let ty_span = tcx.hir.span(tcx.hir.hir_to_node_id(ty_hir_id));
127 opt_ty_info = Some(ty_span);
128 self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
129 match fn_decl.implicit_self {
130 hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
131 hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
132 hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
133 hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
143 ArgInfo(fn_sig.inputs()[index], opt_ty_info, Some(&*arg.pat), self_arg)
146 let arguments = implicit_argument.into_iter().chain(explicit_arguments);
148 let (yield_ty, return_ty) = if body.is_generator {
149 let gen_sig = match ty.sty {
150 ty::Generator(gen_def_id, gen_substs, ..) =>
151 gen_substs.sig(gen_def_id, tcx),
153 span_bug!(tcx.hir.span(id), "generator w/o generator type: {:?}", ty),
155 (Some(gen_sig.yield_ty), gen_sig.return_ty)
157 (None, fn_sig.output())
160 build::construct_fn(cx, id, arguments, safety, abi,
161 return_ty, yield_ty, return_ty_span, body)
163 build::construct_const(cx, body_id, return_ty_span)
166 // Convert the Mir to global types.
167 let mut globalizer = GlobalizeMir {
171 globalizer.visit_mir(&mut mir);
173 mem::transmute::<Mir, Mir<'tcx>>(mir)
176 mir_util::dump_mir(tcx, None, "mir_map", &0,
177 MirSource::item(def_id), &mir, |_, _| Ok(()) );
183 /// A pass to lift all the types and substitutions in a Mir
184 /// to the global tcx. Sadly, we don't have a "folder" that
185 /// can change 'tcx so we have to transmute afterwards.
186 struct GlobalizeMir<'a, 'gcx: 'a> {
187 tcx: TyCtxt<'a, 'gcx, 'gcx>,
191 impl<'a, 'gcx: 'tcx, 'tcx> MutVisitor<'tcx> for GlobalizeMir<'a, 'gcx> {
192 fn visit_ty(&mut self, ty: &mut Ty<'tcx>, _: TyContext) {
193 if let Some(lifted) = self.tcx.lift(ty) {
197 "found type `{:?}` with inference types/regions in MIR",
202 fn visit_region(&mut self, region: &mut ty::Region<'tcx>, _: Location) {
203 if let Some(lifted) = self.tcx.lift(region) {
207 "found region `{:?}` with inference types/regions in MIR",
212 fn visit_const(&mut self, constant: &mut &'tcx ty::Const<'tcx>, _: Location) {
213 if let Some(lifted) = self.tcx.lift(constant) {
217 "found constant `{:?}` with inference types/regions in MIR",
222 fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>, _: Location) {
223 if let Some(lifted) = self.tcx.lift(substs) {
227 "found substs `{:?}` with inference types/regions in MIR",
233 fn create_constructor_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
234 ctor_id: ast::NodeId,
235 v: &'tcx hir::VariantData)
238 let span = tcx.hir.span(ctor_id);
239 if let hir::VariantData::Tuple(ref fields, ctor_id) = *v {
240 tcx.infer_ctxt().enter(|infcx| {
241 let mut mir = shim::build_adt_ctor(&infcx, ctor_id, fields, span);
243 // Convert the Mir to global types.
244 let tcx = infcx.tcx.global_tcx();
245 let mut globalizer = GlobalizeMir {
249 globalizer.visit_mir(&mut mir);
251 mem::transmute::<Mir, Mir<'tcx>>(mir)
254 mir_util::dump_mir(tcx, None, "mir_map", &0,
255 MirSource::item(tcx.hir.local_def_id(ctor_id)),
256 &mir, |_, _| Ok(()) );
261 span_bug!(span, "attempting to create MIR for non-tuple variant {:?}", v);
265 ///////////////////////////////////////////////////////////////////////////
266 // BuildMir -- walks a crate, looking for fn items and methods to build MIR from
268 fn liberated_closure_env_ty<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
269 closure_expr_id: ast::NodeId,
270 body_id: hir::BodyId)
272 let closure_expr_hir_id = tcx.hir.node_to_hir_id(closure_expr_id);
273 let closure_ty = tcx.body_tables(body_id).node_id_to_type(closure_expr_hir_id);
275 let (closure_def_id, closure_substs) = match closure_ty.sty {
276 ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
277 _ => bug!("closure expr does not have closure type: {:?}", closure_ty)
280 let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
281 tcx.liberate_late_bound_regions(closure_def_id, &closure_env_ty)
284 #[derive(Debug, PartialEq, Eq)]
285 pub enum BlockFrame {
286 /// Evaluation is currently within a statement.
288 /// Examples include:
290 /// 2. `let _ = EXPR;`
291 /// 3. `let x = EXPR;`
293 /// If true, then statement discards result from evaluating
294 /// the expression (such as examples 1 and 2 above).
295 ignores_expr_result: bool
298 /// Evaluation is currently within the tail expression of a block.
300 /// Example: `{ STMT_1; STMT_2; EXPR }`
302 /// If true, then the surrounding context of the block ignores
303 /// the result of evaluating the block's tail expression.
305 /// Example: `let _ = { STMT_1; EXPR };`
306 tail_result_is_ignored: bool
309 /// Generic mark meaning that the block occurred as a subexpression
310 /// where the result might be used.
312 /// Examples: `foo(EXPR)`, `match EXPR { ... }`
317 fn is_tail_expr(&self) -> bool {
319 BlockFrame::TailExpr { .. } => true,
321 BlockFrame::Statement { .. } |
322 BlockFrame::SubExpr => false,
325 fn is_statement(&self) -> bool {
327 BlockFrame::Statement { .. } => true,
329 BlockFrame::TailExpr { .. } |
330 BlockFrame::SubExpr => false,
335 struct Builder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
336 hir: Cx<'a, 'gcx, 'tcx>,
342 /// the current set of scopes, updated as we traverse;
343 /// see the `scope` module for more details
344 scopes: Vec<scope::Scope<'tcx>>,
346 /// the block-context: each time we build the code within an hair::Block,
347 /// we push a frame here tracking whether we are building a statement or
348 /// if we are pushing the tail expression of the block. This is used to
349 /// embed information in generated temps about whether they were created
350 /// for a block tail expression or not.
352 /// It would be great if we could fold this into `self.scopes`
353 /// somehow; but right now I think that is very tightly tied to
354 /// the code generation in ways that we cannot (or should not)
355 /// start just throwing new entries onto that vector in order to
356 /// distinguish the context of EXPR1 from the context of EXPR2 in
357 /// `{ STMTS; EXPR1 } + EXPR2`
358 block_context: Vec<BlockFrame>,
360 /// The current unsafe block in scope, even if it is hidden by
361 /// a PushUnsafeBlock
362 unpushed_unsafe: Safety,
364 /// The number of `push_unsafe_block` levels in scope
365 push_unsafe_count: usize,
367 /// the current set of breakables; see the `scope` module for more
369 breakable_scopes: Vec<scope::BreakableScope<'tcx>>,
371 /// the vector of all scopes that we have created thus far;
372 /// we track this for debuginfo later
373 source_scopes: IndexVec<SourceScope, SourceScopeData>,
374 source_scope_local_data: IndexVec<SourceScope, SourceScopeLocalData>,
375 source_scope: SourceScope,
377 /// the guard-context: each time we build the guard expression for
378 /// a match arm, we push onto this stack, and then pop when we
379 /// finish building it.
380 guard_context: Vec<GuardFrame>,
382 /// Maps node ids of variable bindings to the `Local`s created for them.
383 /// (A match binding can have two locals; the 2nd is for the arm's guard.)
384 var_indices: NodeMap<LocalsForNode>,
385 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
386 upvar_decls: Vec<UpvarDecl>,
387 unit_temp: Option<Place<'tcx>>,
389 /// cached block with the RESUME terminator; this is created
390 /// when first set of cleanups are built.
391 cached_resume_block: Option<BasicBlock>,
392 /// cached block with the RETURN terminator
393 cached_return_block: Option<BasicBlock>,
394 /// cached block with the UNREACHABLE terminator
395 cached_unreachable_block: Option<BasicBlock>,
398 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
399 fn is_bound_var_in_guard(&self, id: ast::NodeId) -> bool {
400 self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
403 fn var_local_id(&self, id: ast::NodeId, for_guard: ForGuard) -> Local {
404 self.var_indices[&id].local_id(for_guard)
410 /// In the usual case, a node-id for an identifier maps to at most
411 /// one Local declaration.
414 /// The exceptional case is identifiers in a match arm's pattern
415 /// that are referenced in a guard of that match arm. For these,
416 /// we can have `2+k` Locals, where `k` is the number of candidate
417 /// patterns (separated by `|`) in the arm.
419 /// * `for_arm_body` is the Local used in the arm body (which is
420 /// just like the `One` case above),
422 /// * `ref_for_guard` is the Local used in the arm's guard (which
423 /// is a reference to a temp that is an alias of
426 /// * `vals_for_guard` is the `k` Locals; at most one of them will
427 /// get initialized by the arm's execution, and after it is
428 /// initialized, `ref_for_guard` will be assigned a reference to
431 /// There reason we have `k` Locals rather than just 1 is to
432 /// accommodate some restrictions imposed by two-phase borrows,
433 /// which apply when we have a `ref mut` pattern.
434 ForGuard { vals_for_guard: Vec<Local>, ref_for_guard: Local, for_arm_body: Local },
438 struct GuardFrameLocal {
442 impl GuardFrameLocal {
443 fn new(id: ast::NodeId, _binding_mode: BindingMode) -> Self {
452 /// These are the id's of names that are bound by patterns of the
453 /// arm of *this* guard.
455 /// (Frames higher up the stack will have the id's bound in arms
456 /// further out, such as in a case like:
459 /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1,
462 /// here, when building for FIXME
463 locals: Vec<GuardFrameLocal>,
466 /// ForGuard indicates whether we are talking about:
467 /// 1. the temp for a local binding used solely within guard expressions,
468 /// 2. the temp that holds reference to (1.), which is actually what the
469 /// guard expressions see, or
470 /// 3. the temp for use outside of guard expressions.
471 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
473 /// The `usize` identifies for which candidate pattern we want the
474 /// local binding. We keep a temp per-candidate to accommodate
475 /// two-phase borrows (see `LocalsForNode` documentation).
476 ValWithinGuard(usize),
482 fn local_id(&self, for_guard: ForGuard) -> Local {
483 match (self, for_guard) {
484 (&LocalsForNode::One(local_id), ForGuard::OutsideGuard) |
485 (&LocalsForNode::ForGuard { ref_for_guard: local_id, .. }, ForGuard::RefWithinGuard) |
486 (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) =>
489 (&LocalsForNode::ForGuard { ref vals_for_guard, .. },
490 ForGuard::ValWithinGuard(pat_idx)) =>
491 vals_for_guard[pat_idx],
493 (&LocalsForNode::One(_), ForGuard::ValWithinGuard(_)) |
494 (&LocalsForNode::One(_), ForGuard::RefWithinGuard) =>
495 bug!("anything with one local should never be within a guard."),
501 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
505 pub struct ScopeId { .. }
508 ///////////////////////////////////////////////////////////////////////////
509 /// The `BlockAnd` "monad" packages up the new basic block along with a
510 /// produced value (sometimes just unit, of course). The `unpack!`
511 /// macro (and methods below) makes working with `BlockAnd` much more
514 #[must_use = "if you don't use one of these results, you're leaving a dangling edge"]
515 struct BlockAnd<T>(BasicBlock, T);
517 trait BlockAndExtension {
518 fn and<T>(self, v: T) -> BlockAnd<T>;
519 fn unit(self) -> BlockAnd<()>;
522 impl BlockAndExtension for BasicBlock {
523 fn and<T>(self, v: T) -> BlockAnd<T> {
527 fn unit(self) -> BlockAnd<()> {
532 /// Update a block pointer and return the value.
533 /// Use it like `let x = unpack!(block = self.foo(block, foo))`.
534 macro_rules! unpack {
535 ($x:ident = $c:expr) => {
537 let BlockAnd(b, v) = $c;
545 let BlockAnd(b, ()) = $c;
551 fn should_abort_on_panic<'a, 'gcx, 'tcx>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
555 // Not callable from C, so we can safely unwind through these
556 if abi == Abi::Rust || abi == Abi::RustCall { return false; }
558 // We never unwind, so it's not relevant to stop an unwind
559 if tcx.sess.panic_strategy() != PanicStrategy::Unwind { return false; }
561 // We cannot add landing pads, so don't add one
562 if tcx.sess.no_landing_pads() { return false; }
564 // This is a special case: some functions have a C abi but are meant to
565 // unwind anyway. Don't stop them.
566 let attrs = &tcx.get_attrs(fn_def_id);
567 match attr::find_unwind_attr(Some(tcx.sess.diagnostic()), attrs) {
569 // FIXME(rust-lang/rust#48251) -- Had to disable
570 // abort-on-panic for backwards compatibility reasons.
574 Some(UnwindAttr::Allowed) => false,
575 Some(UnwindAttr::Aborts) => true,
579 ///////////////////////////////////////////////////////////////////////////
580 /// the main entry point for building MIR for a function
582 struct ArgInfo<'gcx>(Ty<'gcx>,
584 Option<&'gcx hir::Pat>,
585 Option<ImplicitSelfKind>);
587 fn construct_fn<'a, 'gcx, 'tcx, A>(hir: Cx<'a, 'gcx, 'tcx>,
593 yield_ty: Option<Ty<'gcx>>,
594 return_ty_span: Span,
595 body: &'gcx hir::Body)
597 where A: Iterator<Item=ArgInfo<'gcx>>
599 let arguments: Vec<_> = arguments.collect();
602 let span = tcx.hir.span(fn_id);
604 // Gather the upvars of a closure, if any.
605 let upvar_decls: Vec<_> = tcx.with_freevars(fn_id, |freevars| {
606 freevars.iter().map(|fv| {
607 let var_id = fv.var_id();
608 let var_hir_id = tcx.hir.node_to_hir_id(var_id);
609 let closure_expr_id = tcx.hir.local_def_id(fn_id);
610 let capture = hir.tables().upvar_capture(ty::UpvarId {
612 closure_expr_id: LocalDefId::from_def_id(closure_expr_id),
614 let by_ref = match capture {
615 ty::UpvarCapture::ByValue => false,
616 ty::UpvarCapture::ByRef(..) => true
618 let mut decl = UpvarDecl {
619 debug_name: keywords::Invalid.name(),
620 var_hir_id: ClearCrossCrate::Set(var_hir_id),
622 mutability: Mutability::Not,
624 if let Some(Node::Binding(pat)) = tcx.hir.find(var_id) {
625 if let hir::PatKind::Binding(_, _, ident, _) = pat.node {
626 decl.debug_name = ident.name;
628 if let Some(&bm) = hir.tables.pat_binding_modes().get(pat.hir_id) {
629 if bm == ty::BindByValue(hir::MutMutable) {
630 decl.mutability = Mutability::Mut;
632 decl.mutability = Mutability::Not;
635 tcx.sess.delay_span_bug(pat.span, "missing binding mode");
643 let mut builder = Builder::new(hir.clone(),
651 let fn_def_id = tcx.hir.local_def_id(fn_id);
652 let call_site_scope = region::Scope {
653 id: body.value.hir_id.local_id,
654 data: region::ScopeData::CallSite
656 let arg_scope = region::Scope {
657 id: body.value.hir_id.local_id,
658 data: region::ScopeData::Arguments
660 let mut block = START_BLOCK;
661 let source_info = builder.source_info(span);
662 let call_site_s = (call_site_scope, source_info);
663 unpack!(block = builder.in_scope(call_site_s, LintLevel::Inherited, block, |builder| {
664 if should_abort_on_panic(tcx, fn_def_id, abi) {
665 builder.schedule_abort();
668 let arg_scope_s = (arg_scope, source_info);
669 unpack!(block = builder.in_scope(arg_scope_s, LintLevel::Inherited, block, |builder| {
670 builder.args_and_body(block, &arguments, arg_scope, &body.value)
672 // Attribute epilogue to function's closing brace
673 let fn_end = span.shrink_to_hi();
674 let source_info = builder.source_info(fn_end);
675 let return_block = builder.return_block();
676 builder.cfg.terminate(block, source_info,
677 TerminatorKind::Goto { target: return_block });
678 builder.cfg.terminate(return_block, source_info,
679 TerminatorKind::Return);
680 // Attribute any unreachable codepaths to the function's closing brace
681 if let Some(unreachable_block) = builder.cached_unreachable_block {
682 builder.cfg.terminate(unreachable_block, source_info,
683 TerminatorKind::Unreachable);
687 assert_eq!(block, builder.return_block());
689 let mut spread_arg = None;
690 if abi == Abi::RustCall {
691 // RustCall pseudo-ABI untuples the last argument.
692 spread_arg = Some(Local::new(arguments.len()));
694 let closure_expr_id = tcx.hir.local_def_id(fn_id);
695 info!("fn_id {:?} has attrs {:?}", closure_expr_id,
696 tcx.get_attrs(closure_expr_id));
698 let mut mir = builder.finish(yield_ty);
699 mir.spread_arg = spread_arg;
703 fn construct_const<'a, 'gcx, 'tcx>(
704 hir: Cx<'a, 'gcx, 'tcx>,
705 body_id: hir::BodyId,
709 let ast_expr = &tcx.hir.body(body_id).value;
710 let ty = hir.tables().expr_ty_adjusted(ast_expr);
711 let owner_id = tcx.hir.body_owner(body_id);
712 let span = tcx.hir.span(owner_id);
713 let mut builder = Builder::new(hir.clone(), span, 0, Safety::Safe, ty, ty_span,vec![]);
715 let mut block = START_BLOCK;
716 let expr = builder.hir.mirror(ast_expr);
717 unpack!(block = builder.into_expr(&Place::Local(RETURN_PLACE), block, expr));
719 let source_info = builder.source_info(span);
720 builder.cfg.terminate(block, source_info, TerminatorKind::Return);
722 // Constants can't `return` so a return block should not be created.
723 assert_eq!(builder.cached_return_block, None);
725 // Constants may be match expressions in which case an unreachable block may
726 // be created, so terminate it properly.
727 if let Some(unreachable_block) = builder.cached_unreachable_block {
728 builder.cfg.terminate(unreachable_block, source_info,
729 TerminatorKind::Unreachable);
735 fn construct_error<'a, 'gcx, 'tcx>(hir: Cx<'a, 'gcx, 'tcx>,
736 body_id: hir::BodyId)
738 let owner_id = hir.tcx().hir.body_owner(body_id);
739 let span = hir.tcx().hir.span(owner_id);
740 let ty = hir.tcx().types.err;
741 let mut builder = Builder::new(hir, span, 0, Safety::Safe, ty, span, vec![]);
742 let source_info = builder.source_info(span);
743 builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
747 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
748 fn new(hir: Cx<'a, 'gcx, 'tcx>,
754 upvar_decls: Vec<UpvarDecl>)
755 -> Builder<'a, 'gcx, 'tcx> {
756 let lint_level = LintLevel::Explicit(hir.root_lint_level);
757 let mut builder = Builder {
759 cfg: CFG { basic_blocks: IndexVec::new() },
763 block_context: vec![],
764 source_scopes: IndexVec::new(),
765 source_scope: OUTERMOST_SOURCE_SCOPE,
766 source_scope_local_data: IndexVec::new(),
767 guard_context: vec![],
768 push_unsafe_count: 0,
769 unpushed_unsafe: safety,
770 breakable_scopes: vec![],
771 local_decls: IndexVec::from_elem_n(
772 LocalDecl::new_return_place(return_ty, return_span),
776 var_indices: NodeMap(),
778 cached_resume_block: None,
779 cached_return_block: None,
780 cached_unreachable_block: None,
783 assert_eq!(builder.cfg.start_new_block(), START_BLOCK);
785 builder.new_source_scope(span, lint_level, Some(safety)),
786 OUTERMOST_SOURCE_SCOPE);
787 builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None;
793 yield_ty: Option<Ty<'tcx>>)
795 for (index, block) in self.cfg.basic_blocks.iter().enumerate() {
796 if block.terminator.is_none() {
797 span_bug!(self.fn_span, "no terminator on block {:?}", index);
801 Mir::new(self.cfg.basic_blocks,
803 ClearCrossCrate::Set(self.source_scope_local_data),
813 fn args_and_body(&mut self,
814 mut block: BasicBlock,
815 arguments: &[ArgInfo<'gcx>],
816 argument_scope: region::Scope,
817 ast_body: &'gcx hir::Expr)
820 // Allocate locals for the function arguments
821 for &ArgInfo(ty, _, pattern, _) in arguments.iter() {
822 // If this is a simple binding pattern, give the local a name for
823 // debuginfo and so that error reporting knows that this is a user
824 // variable. For any other pattern the pattern introduces new
825 // variables which will be named instead.
827 if let Some(pat) = pattern {
829 hir::PatKind::Binding(hir::BindingAnnotation::Unannotated, _, ident, _)
830 | hir::PatKind::Binding(hir::BindingAnnotation::Mutable, _, ident, _) => {
831 name = Some(ident.name);
837 let source_info = SourceInfo {
838 scope: OUTERMOST_SOURCE_SCOPE,
839 span: pattern.map_or(self.fn_span, |pat| pat.span)
841 self.local_decls.push(LocalDecl {
842 mutability: Mutability::Mut,
846 visibility_scope: source_info.scope,
849 is_user_variable: None,
854 let mut scope = None;
855 // Bind the argument patterns
856 for (index, arg_info) in arguments.iter().enumerate() {
857 // Function arguments always get the first Local indices after the return place
858 let local = Local::new(index + 1);
859 let place = Place::Local(local);
860 let &ArgInfo(ty, opt_ty_info, pattern, ref self_binding) = arg_info;
862 if let Some(pattern) = pattern {
863 let pattern = self.hir.pattern_from_hir(pattern);
864 let span = pattern.span;
866 match *pattern.kind {
867 // Don't introduce extra copies for simple bindings
868 PatternKind::Binding { mutability, var, mode: BindingMode::ByValue, .. } => {
869 self.local_decls[local].mutability = mutability;
870 self.local_decls[local].is_user_variable =
871 if let Some(kind) = self_binding {
872 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind)))
874 let binding_mode = ty::BindingMode::BindByValue(mutability.into());
875 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
878 opt_match_place: Some((Some(place.clone()), span)),
882 self.var_indices.insert(var, LocalsForNode::One(local));
885 scope = self.declare_bindings(scope, ast_body.span,
886 LintLevel::Inherited, &[pattern.clone()],
887 matches::ArmHasGuard(false),
888 Some((Some(&place), span)));
889 unpack!(block = self.place_into_pattern(block, pattern, &place, false));
894 // Make sure we drop (parts of) the argument even when not matched on.
896 pattern.as_ref().map_or(ast_body.span, |pat| pat.span),
897 argument_scope, &place, ty,
898 DropKind::Value { cached_block: CachedBlock::default() },
902 // Enter the argument pattern bindings source scope, if it exists.
903 if let Some(source_scope) = scope {
904 self.source_scope = source_scope;
907 let body = self.hir.mirror(ast_body);
908 self.into(&Place::Local(RETURN_PLACE), block, body)
911 fn get_unit_temp(&mut self) -> Place<'tcx> {
912 match self.unit_temp {
913 Some(ref tmp) => tmp.clone(),
915 let ty = self.hir.unit_ty();
916 let fn_span = self.fn_span;
917 let tmp = self.temp(ty, fn_span);
918 self.unit_temp = Some(tmp.clone());
924 fn return_block(&mut self) -> BasicBlock {
925 match self.cached_return_block {
928 let rb = self.cfg.start_new_block();
929 self.cached_return_block = Some(rb);
935 fn unreachable_block(&mut self) -> BasicBlock {
936 match self.cached_unreachable_block {
939 let ub = self.cfg.start_new_block();
940 self.cached_unreachable_block = Some(ub);
947 ///////////////////////////////////////////////////////////////////////////
948 // Builder methods are broken up into modules, depending on what kind
949 // of thing is being lowered. Note that they use the `unpack` macro
950 // above extensively.