| use crate::build; |
| use crate::build::scope::DropKind; |
| use crate::hair::cx::Cx; |
| use crate::hair::{LintLevel, BindingMode, PatternKind}; |
| use crate::transform::MirSource; |
| use crate::util as mir_util; |
| use rustc::hir; |
| use rustc::hir::Node; |
| use rustc::hir::def_id::DefId; |
| use rustc::middle::region; |
| use rustc::mir::*; |
| use rustc::ty::{self, Ty, TyCtxt}; |
| use rustc::util::nodemap::HirIdMap; |
| use rustc_target::spec::PanicStrategy; |
| use rustc_data_structures::indexed_vec::{IndexVec, Idx}; |
| use std::u32; |
| use rustc_target::spec::abi::Abi; |
| use syntax::attr::{self, UnwindAttr}; |
| use syntax::symbol::kw; |
| use syntax_pos::Span; |
| |
| use super::lints; |
| |
| /// Construct the MIR for a given `DefId`. |
| pub fn mir_build(tcx: TyCtxt<'_>, def_id: DefId) -> Body<'_> { |
| let id = tcx.hir().as_local_hir_id(def_id).unwrap(); |
| |
| // Figure out what primary body this item has. |
| let (body_id, return_ty_span) = match tcx.hir().get(id) { |
| Node::Expr(hir::Expr { node: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) |
| | Node::Item(hir::Item { node: hir::ItemKind::Fn(decl, _, _, body_id), .. }) |
| | Node::ImplItem( |
| hir::ImplItem { |
| node: hir::ImplItemKind::Method(hir::MethodSig { decl, .. }, body_id), |
| .. |
| } |
| ) |
| | Node::TraitItem( |
| hir::TraitItem { |
| node: hir::TraitItemKind::Method( |
| hir::MethodSig { decl, .. }, |
| hir::TraitMethod::Provided(body_id), |
| ), |
| .. |
| } |
| ) => { |
| (*body_id, decl.output.span()) |
| } |
| Node::Item(hir::Item { node: hir::ItemKind::Static(ty, _, body_id), .. }) |
| | Node::Item(hir::Item { node: hir::ItemKind::Const(ty, body_id), .. }) |
| | Node::ImplItem(hir::ImplItem { node: hir::ImplItemKind::Const(ty, body_id), .. }) |
| | Node::TraitItem( |
| hir::TraitItem { node: hir::TraitItemKind::Const(ty, Some(body_id)), .. } |
| ) => { |
| (*body_id, ty.span) |
| } |
| Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => { |
| (*body, tcx.hir().span(*hir_id)) |
| } |
| |
| _ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def_id), |
| }; |
| |
| tcx.infer_ctxt().enter(|infcx| { |
| let cx = Cx::new(&infcx, id); |
| let body = if cx.tables().tainted_by_errors { |
| build::construct_error(cx, body_id) |
| } else if cx.body_owner_kind.is_fn_or_closure() { |
| // fetch the fully liberated fn signature (that is, all bound |
| // types/lifetimes replaced) |
| let fn_sig = cx.tables().liberated_fn_sigs()[id].clone(); |
| let fn_def_id = tcx.hir().local_def_id(id); |
| |
| let ty = tcx.type_of(fn_def_id); |
| let mut abi = fn_sig.abi; |
| let implicit_argument = match ty.sty { |
| ty::Closure(..) => { |
| // HACK(eddyb) Avoid having RustCall on closures, |
| // as it adds unnecessary (and wrong) auto-tupling. |
| abi = Abi::Rust; |
| Some(ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)) |
| } |
| ty::Generator(..) => { |
| let gen_ty = tcx.body_tables(body_id).node_type(id); |
| Some(ArgInfo(gen_ty, None, None, None)) |
| } |
| _ => None, |
| }; |
| |
| let safety = match fn_sig.unsafety { |
| hir::Unsafety::Normal => Safety::Safe, |
| hir::Unsafety::Unsafe => Safety::FnUnsafe, |
| }; |
| |
| let body = tcx.hir().body(body_id); |
| let explicit_arguments = |
| body.params |
| .iter() |
| .enumerate() |
| .map(|(index, arg)| { |
| let owner_id = tcx.hir().body_owner(body_id); |
| let opt_ty_info; |
| let self_arg; |
| if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) { |
| let ty_hir_id = fn_decl.inputs[index].hir_id; |
| let ty_span = tcx.hir().span(ty_hir_id); |
| opt_ty_info = Some(ty_span); |
| self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() { |
| match fn_decl.implicit_self { |
| hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm), |
| hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut), |
| hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef), |
| hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef), |
| _ => None, |
| } |
| } else { |
| None |
| }; |
| } else { |
| opt_ty_info = None; |
| self_arg = None; |
| } |
| |
| ArgInfo(fn_sig.inputs()[index], opt_ty_info, Some(&arg), self_arg) |
| }); |
| |
| let arguments = implicit_argument.into_iter().chain(explicit_arguments); |
| |
| let (yield_ty, return_ty) = if body.generator_kind.is_some() { |
| let gen_sig = match ty.sty { |
| ty::Generator(gen_def_id, gen_substs, ..) => |
| gen_substs.sig(gen_def_id, tcx), |
| _ => |
| span_bug!(tcx.hir().span(id), |
| "generator w/o generator type: {:?}", ty), |
| }; |
| (Some(gen_sig.yield_ty), gen_sig.return_ty) |
| } else { |
| (None, fn_sig.output()) |
| }; |
| |
| build::construct_fn(cx, id, arguments, safety, abi, |
| return_ty, yield_ty, return_ty_span, body) |
| } else { |
| // Get the revealed type of this const. This is *not* the adjusted |
| // type of its body, which may be a subtype of this type. For |
| // example: |
| // |
| // fn foo(_: &()) {} |
| // static X: fn(&'static ()) = foo; |
| // |
| // The adjusted type of the body of X is `for<'a> fn(&'a ())` which |
| // is not the same as the type of X. We need the type of the return |
| // place to be the type of the constant because NLL typeck will |
| // equate them. |
| |
| let return_ty = cx.tables().node_type(id); |
| |
| build::construct_const(cx, body_id, return_ty, return_ty_span) |
| }; |
| |
| mir_util::dump_mir(tcx, None, "mir_map", &0, |
| MirSource::item(def_id), &body, |_, _| Ok(()) ); |
| |
| lints::check(tcx, &body, def_id); |
| |
| body |
| }) |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // BuildMir -- walks a crate, looking for fn items and methods to build MIR from |
| |
| fn liberated_closure_env_ty( |
| tcx: TyCtxt<'_>, |
| closure_expr_id: hir::HirId, |
| body_id: hir::BodyId, |
| ) -> Ty<'_> { |
| let closure_ty = tcx.body_tables(body_id).node_type(closure_expr_id); |
| |
| let (closure_def_id, closure_substs) = match closure_ty.sty { |
| ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs), |
| _ => bug!("closure expr does not have closure type: {:?}", closure_ty) |
| }; |
| |
| let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap(); |
| tcx.liberate_late_bound_regions(closure_def_id, &closure_env_ty) |
| } |
| |
| #[derive(Debug, PartialEq, Eq)] |
| pub enum BlockFrame { |
| /// Evaluation is currently within a statement. |
| /// |
| /// Examples include: |
| /// 1. `EXPR;` |
| /// 2. `let _ = EXPR;` |
| /// 3. `let x = EXPR;` |
| Statement { |
| /// If true, then statement discards result from evaluating |
| /// the expression (such as examples 1 and 2 above). |
| ignores_expr_result: bool |
| }, |
| |
| /// Evaluation is currently within the tail expression of a block. |
| /// |
| /// Example: `{ STMT_1; STMT_2; EXPR }` |
| TailExpr { |
| /// If true, then the surrounding context of the block ignores |
| /// the result of evaluating the block's tail expression. |
| /// |
| /// Example: `let _ = { STMT_1; EXPR };` |
| tail_result_is_ignored: bool |
| }, |
| |
| /// Generic mark meaning that the block occurred as a subexpression |
| /// where the result might be used. |
| /// |
| /// Examples: `foo(EXPR)`, `match EXPR { ... }` |
| SubExpr, |
| } |
| |
| impl BlockFrame { |
| fn is_tail_expr(&self) -> bool { |
| match *self { |
| BlockFrame::TailExpr { .. } => true, |
| |
| BlockFrame::Statement { .. } | |
| BlockFrame::SubExpr => false, |
| } |
| } |
| fn is_statement(&self) -> bool { |
| match *self { |
| BlockFrame::Statement { .. } => true, |
| |
| BlockFrame::TailExpr { .. } | |
| BlockFrame::SubExpr => false, |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| struct BlockContext(Vec<BlockFrame>); |
| |
| struct Builder<'a, 'tcx> { |
| hir: Cx<'a, 'tcx>, |
| cfg: CFG<'tcx>, |
| |
| fn_span: Span, |
| arg_count: usize, |
| is_generator: bool, |
| |
| /// The current set of scopes, updated as we traverse; |
| /// see the `scope` module for more details. |
| scopes: scope::Scopes<'tcx>, |
| |
| /// The block-context: each time we build the code within an hair::Block, |
| /// we push a frame here tracking whether we are building a statement or |
| /// if we are pushing the tail expression of the block. This is used to |
| /// embed information in generated temps about whether they were created |
| /// for a block tail expression or not. |
| /// |
| /// It would be great if we could fold this into `self.scopes` |
| /// somehow, but right now I think that is very tightly tied to |
| /// the code generation in ways that we cannot (or should not) |
| /// start just throwing new entries onto that vector in order to |
| /// distinguish the context of EXPR1 from the context of EXPR2 in |
| /// `{ STMTS; EXPR1 } + EXPR2`. |
| block_context: BlockContext, |
| |
| /// The current unsafe block in scope, even if it is hidden by |
| /// a `PushUnsafeBlock`. |
| unpushed_unsafe: Safety, |
| |
| /// The number of `push_unsafe_block` levels in scope. |
| push_unsafe_count: usize, |
| |
| /// The vector of all scopes that we have created thus far; |
| /// we track this for debuginfo later. |
| source_scopes: IndexVec<SourceScope, SourceScopeData>, |
| source_scope_local_data: IndexVec<SourceScope, SourceScopeLocalData>, |
| source_scope: SourceScope, |
| |
| /// The guard-context: each time we build the guard expression for |
| /// a match arm, we push onto this stack, and then pop when we |
| /// finish building it. |
| guard_context: Vec<GuardFrame>, |
| |
| /// Maps `HirId`s of variable bindings to the `Local`s created for them. |
| /// (A match binding can have two locals; the 2nd is for the arm's guard.) |
| var_indices: HirIdMap<LocalsForNode>, |
| local_decls: IndexVec<Local, LocalDecl<'tcx>>, |
| canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>, |
| __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>, |
| upvar_mutbls: Vec<Mutability>, |
| unit_temp: Option<Place<'tcx>>, |
| |
| /// Cached block with the `RESUME` terminator; this is created |
| /// when first set of cleanups are built. |
| cached_resume_block: Option<BasicBlock>, |
| /// Cached block with the `RETURN` terminator. |
| cached_return_block: Option<BasicBlock>, |
| /// Cached block with the `UNREACHABLE` terminator. |
| cached_unreachable_block: Option<BasicBlock>, |
| } |
| |
| impl<'a, 'tcx> Builder<'a, 'tcx> { |
| fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool { |
| self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id)) |
| } |
| |
| fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local { |
| self.var_indices[&id].local_id(for_guard) |
| } |
| } |
| |
| impl BlockContext { |
| fn new() -> Self { BlockContext(vec![]) } |
| fn push(&mut self, bf: BlockFrame) { self.0.push(bf); } |
| fn pop(&mut self) -> Option<BlockFrame> { self.0.pop() } |
| |
| /// Traverses the frames on the `BlockContext`, searching for either |
| /// the first block-tail expression frame with no intervening |
| /// statement frame. |
| /// |
| /// Notably, this skips over `SubExpr` frames; this method is |
| /// meant to be used in the context of understanding the |
| /// relationship of a temp (created within some complicated |
| /// expression) with its containing expression, and whether the |
| /// value of that *containing expression* (not the temp!) is |
| /// ignored. |
| fn currently_in_block_tail(&self) -> Option<BlockTailInfo> { |
| for bf in self.0.iter().rev() { |
| match bf { |
| BlockFrame::SubExpr => continue, |
| BlockFrame::Statement { .. } => break, |
| &BlockFrame::TailExpr { tail_result_is_ignored } => |
| return Some(BlockTailInfo { tail_result_is_ignored }) |
| } |
| } |
| |
| return None; |
| } |
| |
| /// Looks at the topmost frame on the BlockContext and reports |
| /// whether its one that would discard a block tail result. |
| /// |
| /// Unlike `currently_within_ignored_tail_expression`, this does |
| /// *not* skip over `SubExpr` frames: here, we want to know |
| /// whether the block result itself is discarded. |
| fn currently_ignores_tail_results(&self) -> bool { |
| match self.0.last() { |
| // no context: conservatively assume result is read |
| None => false, |
| |
| // sub-expression: block result feeds into some computation |
| Some(BlockFrame::SubExpr) => false, |
| |
| // otherwise: use accumulated is_ignored state. |
| Some(BlockFrame::TailExpr { tail_result_is_ignored: ignored }) | |
| Some(BlockFrame::Statement { ignores_expr_result: ignored }) => *ignored, |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| enum LocalsForNode { |
| /// In the usual case, a `HirId` for an identifier maps to at most |
| /// one `Local` declaration. |
| One(Local), |
| |
| /// The exceptional case is identifiers in a match arm's pattern |
| /// that are referenced in a guard of that match arm. For these, |
| /// we have `2` Locals. |
| /// |
| /// * `for_arm_body` is the Local used in the arm body (which is |
| /// just like the `One` case above), |
| /// |
| /// * `ref_for_guard` is the Local used in the arm's guard (which |
| /// is a reference to a temp that is an alias of |
| /// `for_arm_body`). |
| ForGuard { ref_for_guard: Local, for_arm_body: Local }, |
| } |
| |
| #[derive(Debug)] |
| struct GuardFrameLocal { |
| id: hir::HirId, |
| } |
| |
| impl GuardFrameLocal { |
| fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self { |
| GuardFrameLocal { |
| id: id, |
| } |
| } |
| } |
| |
| #[derive(Debug)] |
| struct GuardFrame { |
| /// These are the id's of names that are bound by patterns of the |
| /// arm of *this* guard. |
| /// |
| /// (Frames higher up the stack will have the id's bound in arms |
| /// further out, such as in a case like: |
| /// |
| /// match E1 { |
| /// P1(id1) if (... (match E2 { P2(id2) if ... => B2 })) => B1, |
| /// } |
| /// |
| /// here, when building for FIXME. |
| locals: Vec<GuardFrameLocal>, |
| } |
| |
| /// `ForGuard` indicates whether we are talking about: |
| /// 1. The variable for use outside of guard expressions, or |
| /// 2. The temp that holds reference to (1.), which is actually what the |
| /// guard expressions see. |
| #[derive(Copy, Clone, Debug, PartialEq, Eq)] |
| enum ForGuard { |
| RefWithinGuard, |
| OutsideGuard, |
| } |
| |
| impl LocalsForNode { |
| fn local_id(&self, for_guard: ForGuard) -> Local { |
| match (self, for_guard) { |
| (&LocalsForNode::One(local_id), ForGuard::OutsideGuard) | |
| (&LocalsForNode::ForGuard { ref_for_guard: local_id, .. }, ForGuard::RefWithinGuard) | |
| (&LocalsForNode::ForGuard { for_arm_body: local_id, .. }, ForGuard::OutsideGuard) => |
| local_id, |
| |
| (&LocalsForNode::One(_), ForGuard::RefWithinGuard) => |
| bug!("anything with one local should never be within a guard."), |
| } |
| } |
| } |
| |
| struct CFG<'tcx> { |
| basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, |
| } |
| |
| newtype_index! { |
| pub struct ScopeId { .. } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| /// The `BlockAnd` "monad" packages up the new basic block along with a |
| /// produced value (sometimes just unit, of course). The `unpack!` |
| /// macro (and methods below) makes working with `BlockAnd` much more |
| /// convenient. |
| |
| #[must_use = "if you don't use one of these results, you're leaving a dangling edge"] |
| struct BlockAnd<T>(BasicBlock, T); |
| |
| trait BlockAndExtension { |
| fn and<T>(self, v: T) -> BlockAnd<T>; |
| fn unit(self) -> BlockAnd<()>; |
| } |
| |
| impl BlockAndExtension for BasicBlock { |
| fn and<T>(self, v: T) -> BlockAnd<T> { |
| BlockAnd(self, v) |
| } |
| |
| fn unit(self) -> BlockAnd<()> { |
| BlockAnd(self, ()) |
| } |
| } |
| |
| /// Update a block pointer and return the value. |
| /// Use it like `let x = unpack!(block = self.foo(block, foo))`. |
| macro_rules! unpack { |
| ($x:ident = $c:expr) => { |
| { |
| let BlockAnd(b, v) = $c; |
| $x = b; |
| v |
| } |
| }; |
| |
| ($c:expr) => { |
| { |
| let BlockAnd(b, ()) = $c; |
| b |
| } |
| }; |
| } |
| |
| fn should_abort_on_panic(tcx: TyCtxt<'_>, fn_def_id: DefId, abi: Abi) -> bool { |
| // Not callable from C, so we can safely unwind through these |
| if abi == Abi::Rust || abi == Abi::RustCall { return false; } |
| |
| // Validate `#[unwind]` syntax regardless of platform-specific panic strategy |
| let attrs = &tcx.get_attrs(fn_def_id); |
| let unwind_attr = attr::find_unwind_attr(Some(tcx.sess.diagnostic()), attrs); |
| |
| // We never unwind, so it's not relevant to stop an unwind |
| if tcx.sess.panic_strategy() != PanicStrategy::Unwind { return false; } |
| |
| // We cannot add landing pads, so don't add one |
| if tcx.sess.no_landing_pads() { return false; } |
| |
| // This is a special case: some functions have a C abi but are meant to |
| // unwind anyway. Don't stop them. |
| match unwind_attr { |
| None => false, // FIXME(#58794) |
| Some(UnwindAttr::Allowed) => false, |
| Some(UnwindAttr::Aborts) => true, |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| /// the main entry point for building MIR for a function |
| |
| struct ArgInfo<'tcx>(Ty<'tcx>, Option<Span>, Option<&'tcx hir::Param>, Option<ImplicitSelfKind>); |
| |
| fn construct_fn<'a, 'tcx, A>( |
| hir: Cx<'a, 'tcx>, |
| fn_id: hir::HirId, |
| arguments: A, |
| safety: Safety, |
| abi: Abi, |
| return_ty: Ty<'tcx>, |
| yield_ty: Option<Ty<'tcx>>, |
| return_ty_span: Span, |
| body: &'tcx hir::Body, |
| ) -> Body<'tcx> |
| where |
| A: Iterator<Item=ArgInfo<'tcx>> |
| { |
| let arguments: Vec<_> = arguments.collect(); |
| |
| let tcx = hir.tcx(); |
| let tcx_hir = tcx.hir(); |
| let span = tcx_hir.span(fn_id); |
| |
| let hir_tables = hir.tables(); |
| let fn_def_id = tcx_hir.local_def_id(fn_id); |
| |
| // Gather the upvars of a closure, if any. |
| let mut upvar_mutbls = vec![]; |
| // In analyze_closure() in upvar.rs we gathered a list of upvars used by a |
| // closure and we stored in a map called upvar_list in TypeckTables indexed |
| // with the closure's DefId. Here, we run through that vec of UpvarIds for |
| // the given closure and use the necessary information to create UpvarDecl. |
| let upvar_debuginfo: Vec<_> = hir_tables |
| .upvar_list |
| .get(&fn_def_id) |
| .into_iter() |
| .flatten() |
| .map(|(&var_hir_id, &upvar_id)| { |
| let capture = hir_tables.upvar_capture(upvar_id); |
| let by_ref = match capture { |
| ty::UpvarCapture::ByValue => false, |
| ty::UpvarCapture::ByRef(..) => true, |
| }; |
| let mut debuginfo = UpvarDebuginfo { |
| debug_name: kw::Invalid, |
| by_ref, |
| }; |
| let mut mutability = Mutability::Not; |
| if let Some(Node::Binding(pat)) = tcx_hir.find(var_hir_id) { |
| if let hir::PatKind::Binding(_, _, ident, _) = pat.node { |
| debuginfo.debug_name = ident.name; |
| if let Some(&bm) = hir.tables.pat_binding_modes().get(pat.hir_id) { |
| if bm == ty::BindByValue(hir::MutMutable) { |
| mutability = Mutability::Mut; |
| } else { |
| mutability = Mutability::Not; |
| } |
| } else { |
| tcx.sess.delay_span_bug(pat.span, "missing binding mode"); |
| } |
| } |
| } |
| upvar_mutbls.push(mutability); |
| debuginfo |
| }) |
| .collect(); |
| |
| let mut builder = Builder::new(hir, |
| span, |
| arguments.len(), |
| safety, |
| return_ty, |
| return_ty_span, |
| upvar_debuginfo, |
| upvar_mutbls, |
| body.generator_kind.is_some()); |
| |
| let call_site_scope = region::Scope { |
| id: body.value.hir_id.local_id, |
| data: region::ScopeData::CallSite |
| }; |
| let arg_scope = region::Scope { |
| id: body.value.hir_id.local_id, |
| data: region::ScopeData::Arguments |
| }; |
| let mut block = START_BLOCK; |
| let source_info = builder.source_info(span); |
| let call_site_s = (call_site_scope, source_info); |
| unpack!(block = builder.in_scope(call_site_s, LintLevel::Inherited, |builder| { |
| if should_abort_on_panic(tcx, fn_def_id, abi) { |
| builder.schedule_abort(); |
| } |
| |
| let arg_scope_s = (arg_scope, source_info); |
| // `return_block` is called when we evaluate a `return` expression, so |
| // we just use `START_BLOCK` here. |
| unpack!(block = builder.in_breakable_scope( |
| None, |
| START_BLOCK, |
| Place::return_place(), |
| |builder| { |
| builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| { |
| builder.args_and_body(block, &arguments, arg_scope, &body.value) |
| }) |
| }, |
| )); |
| // Attribute epilogue to function's closing brace |
| let fn_end = span.shrink_to_hi(); |
| let source_info = builder.source_info(fn_end); |
| let return_block = builder.return_block(); |
| builder.cfg.terminate(block, source_info, |
| TerminatorKind::Goto { target: return_block }); |
| builder.cfg.terminate(return_block, source_info, |
| TerminatorKind::Return); |
| // Attribute any unreachable codepaths to the function's closing brace |
| if let Some(unreachable_block) = builder.cached_unreachable_block { |
| builder.cfg.terminate(unreachable_block, source_info, |
| TerminatorKind::Unreachable); |
| } |
| return_block.unit() |
| })); |
| assert_eq!(block, builder.return_block()); |
| |
| let mut spread_arg = None; |
| if abi == Abi::RustCall { |
| // RustCall pseudo-ABI untuples the last argument. |
| spread_arg = Some(Local::new(arguments.len())); |
| } |
| info!("fn_id {:?} has attrs {:?}", fn_def_id, |
| tcx.get_attrs(fn_def_id)); |
| |
| let mut body = builder.finish(yield_ty); |
| body.spread_arg = spread_arg; |
| body |
| } |
| |
| fn construct_const<'a, 'tcx>( |
| hir: Cx<'a, 'tcx>, |
| body_id: hir::BodyId, |
| const_ty: Ty<'tcx>, |
| const_ty_span: Span, |
| ) -> Body<'tcx> { |
| let tcx = hir.tcx(); |
| let owner_id = tcx.hir().body_owner(body_id); |
| let span = tcx.hir().span(owner_id); |
| let mut builder = Builder::new( |
| hir, |
| span, |
| 0, |
| Safety::Safe, |
| const_ty, |
| const_ty_span, |
| vec![], |
| vec![], |
| false, |
| ); |
| |
| let mut block = START_BLOCK; |
| let ast_expr = &tcx.hir().body(body_id).value; |
| let expr = builder.hir.mirror(ast_expr); |
| unpack!(block = builder.into_expr(&Place::return_place(), block, expr)); |
| |
| let source_info = builder.source_info(span); |
| builder.cfg.terminate(block, source_info, TerminatorKind::Return); |
| |
| // Constants can't `return` so a return block should not be created. |
| assert_eq!(builder.cached_return_block, None); |
| |
| // Constants may be match expressions in which case an unreachable block may |
| // be created, so terminate it properly. |
| if let Some(unreachable_block) = builder.cached_unreachable_block { |
| builder.cfg.terminate(unreachable_block, source_info, |
| TerminatorKind::Unreachable); |
| } |
| |
| builder.finish(None) |
| } |
| |
| fn construct_error<'a, 'tcx>( |
| hir: Cx<'a, 'tcx>, |
| body_id: hir::BodyId |
| ) -> Body<'tcx> { |
| let owner_id = hir.tcx().hir().body_owner(body_id); |
| let span = hir.tcx().hir().span(owner_id); |
| let ty = hir.tcx().types.err; |
| let mut builder = Builder::new(hir, span, 0, Safety::Safe, ty, span, vec![], vec![], false); |
| let source_info = builder.source_info(span); |
| builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable); |
| builder.finish(None) |
| } |
| |
| impl<'a, 'tcx> Builder<'a, 'tcx> { |
| fn new(hir: Cx<'a, 'tcx>, |
| span: Span, |
| arg_count: usize, |
| safety: Safety, |
| return_ty: Ty<'tcx>, |
| return_span: Span, |
| __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>, |
| upvar_mutbls: Vec<Mutability>, |
| is_generator: bool) |
| -> Builder<'a, 'tcx> { |
| let lint_level = LintLevel::Explicit(hir.root_lint_level); |
| let mut builder = Builder { |
| hir, |
| cfg: CFG { basic_blocks: IndexVec::new() }, |
| fn_span: span, |
| arg_count, |
| is_generator, |
| scopes: Default::default(), |
| block_context: BlockContext::new(), |
| source_scopes: IndexVec::new(), |
| source_scope: OUTERMOST_SOURCE_SCOPE, |
| source_scope_local_data: IndexVec::new(), |
| guard_context: vec![], |
| push_unsafe_count: 0, |
| unpushed_unsafe: safety, |
| local_decls: IndexVec::from_elem_n( |
| LocalDecl::new_return_place(return_ty, return_span), |
| 1, |
| ), |
| canonical_user_type_annotations: IndexVec::new(), |
| __upvar_debuginfo_codegen_only_do_not_use, |
| upvar_mutbls, |
| var_indices: Default::default(), |
| unit_temp: None, |
| cached_resume_block: None, |
| cached_return_block: None, |
| cached_unreachable_block: None, |
| }; |
| |
| assert_eq!(builder.cfg.start_new_block(), START_BLOCK); |
| assert_eq!( |
| builder.new_source_scope(span, lint_level, Some(safety)), |
| OUTERMOST_SOURCE_SCOPE); |
| builder.source_scopes[OUTERMOST_SOURCE_SCOPE].parent_scope = None; |
| |
| builder |
| } |
| |
| fn finish(self, |
| yield_ty: Option<Ty<'tcx>>) |
| -> Body<'tcx> { |
| for (index, block) in self.cfg.basic_blocks.iter().enumerate() { |
| if block.terminator.is_none() { |
| span_bug!(self.fn_span, "no terminator on block {:?}", index); |
| } |
| } |
| |
| Body::new( |
| self.cfg.basic_blocks, |
| self.source_scopes, |
| ClearCrossCrate::Set(self.source_scope_local_data), |
| yield_ty, |
| self.local_decls, |
| self.canonical_user_type_annotations, |
| self.arg_count, |
| self.__upvar_debuginfo_codegen_only_do_not_use, |
| self.fn_span, |
| self.hir.control_flow_destroyed(), |
| ) |
| } |
| |
| fn args_and_body(&mut self, |
| mut block: BasicBlock, |
| arguments: &[ArgInfo<'tcx>], |
| argument_scope: region::Scope, |
| ast_body: &'tcx hir::Expr) |
| -> BlockAnd<()> |
| { |
| // Allocate locals for the function arguments |
| for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() { |
| // If this is a simple binding pattern, give the local a name for |
| // debuginfo and so that error reporting knows that this is a user |
| // variable. For any other pattern the pattern introduces new |
| // variables which will be named instead. |
| let (name, span) = if let Some(arg) = arg_opt { |
| (arg.pat.simple_ident().map(|ident| ident.name), arg.pat.span) |
| } else { |
| (None, self.fn_span) |
| }; |
| |
| let source_info = SourceInfo { scope: OUTERMOST_SOURCE_SCOPE, span, }; |
| self.local_decls.push(LocalDecl { |
| mutability: Mutability::Mut, |
| ty, |
| user_ty: UserTypeProjections::none(), |
| source_info, |
| visibility_scope: source_info.scope, |
| name, |
| internal: false, |
| is_user_variable: None, |
| is_block_tail: None, |
| }); |
| } |
| |
| let mut scope = None; |
| // Bind the argument patterns |
| for (index, arg_info) in arguments.iter().enumerate() { |
| // Function arguments always get the first Local indices after the return place |
| let local = Local::new(index + 1); |
| let place = Place::from(local); |
| let &ArgInfo(ty, opt_ty_info, arg_opt, ref self_binding) = arg_info; |
| |
| // Make sure we drop (parts of) the argument even when not matched on. |
| self.schedule_drop( |
| arg_opt.as_ref().map_or(ast_body.span, |arg| arg.pat.span), |
| argument_scope, local, ty, DropKind::Value, |
| ); |
| |
| if let Some(arg) = arg_opt { |
| let pattern = self.hir.pattern_from_hir(&arg.pat); |
| let original_source_scope = self.source_scope; |
| let span = pattern.span; |
| self.set_correct_source_scope_for_arg(arg.hir_id, original_source_scope, span); |
| match *pattern.kind { |
| // Don't introduce extra copies for simple bindings |
| PatternKind::Binding { |
| mutability, |
| var, |
| mode: BindingMode::ByValue, |
| subpattern: None, |
| .. |
| } => { |
| self.local_decls[local].mutability = mutability; |
| self.local_decls[local].source_info.scope = self.source_scope; |
| self.local_decls[local].is_user_variable = |
| if let Some(kind) = self_binding { |
| Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(*kind))) |
| } else { |
| let binding_mode = ty::BindingMode::BindByValue(mutability.into()); |
| Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm { |
| binding_mode, |
| opt_ty_info, |
| opt_match_place: Some((Some(place.clone()), span)), |
| pat_span: span, |
| }))) |
| }; |
| self.var_indices.insert(var, LocalsForNode::One(local)); |
| } |
| _ => { |
| scope = self.declare_bindings( |
| scope, |
| ast_body.span, |
| &pattern, |
| matches::ArmHasGuard(false), |
| Some((Some(&place), span)), |
| ); |
| unpack!(block = self.place_into_pattern(block, pattern, &place, false)); |
| } |
| } |
| self.source_scope = original_source_scope; |
| } |
| } |
| |
| // Enter the argument pattern bindings source scope, if it exists. |
| if let Some(source_scope) = scope { |
| self.source_scope = source_scope; |
| } |
| |
| let body = self.hir.mirror(ast_body); |
| self.into(&Place::return_place(), block, body) |
| } |
| |
| fn set_correct_source_scope_for_arg( |
| &mut self, |
| arg_hir_id: hir::HirId, |
| original_source_scope: SourceScope, |
| pattern_span: Span |
| ) { |
| let tcx = self.hir.tcx(); |
| let current_root = tcx.maybe_lint_level_root_bounded( |
| arg_hir_id, |
| self.hir.root_lint_level |
| ); |
| let parent_root = tcx.maybe_lint_level_root_bounded( |
| self.source_scope_local_data[original_source_scope].lint_root, |
| self.hir.root_lint_level, |
| ); |
| if current_root != parent_root { |
| self.source_scope = self.new_source_scope( |
| pattern_span, |
| LintLevel::Explicit(current_root), |
| None |
| ); |
| } |
| } |
| |
| fn get_unit_temp(&mut self) -> Place<'tcx> { |
| match self.unit_temp { |
| Some(ref tmp) => tmp.clone(), |
| None => { |
| let ty = self.hir.unit_ty(); |
| let fn_span = self.fn_span; |
| let tmp = self.temp(ty, fn_span); |
| self.unit_temp = Some(tmp.clone()); |
| tmp |
| } |
| } |
| } |
| |
| fn return_block(&mut self) -> BasicBlock { |
| match self.cached_return_block { |
| Some(rb) => rb, |
| None => { |
| let rb = self.cfg.start_new_block(); |
| self.cached_return_block = Some(rb); |
| rb |
| } |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Builder methods are broken up into modules, depending on what kind |
| // of thing is being lowered. Note that they use the `unpack` macro |
| // above extensively. |
| |
| mod block; |
| mod cfg; |
| mod expr; |
| mod into; |
| mod matches; |
| mod misc; |
| mod scope; |
