1077 lines
39 KiB
Rust
1077 lines
39 KiB
Rust
use crate::build;
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use crate::build::expr::as_place::PlaceBuilder;
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use crate::build::scope::DropKind;
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use crate::thir::{build_thir, Arena, BindingMode, Expr, LintLevel, Pat, PatKind};
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use rustc_attr::{self as attr, UnwindAttr};
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use rustc_errors::ErrorReported;
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use rustc_hir as hir;
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use rustc_hir::def_id::{DefId, LocalDefId};
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use rustc_hir::lang_items::LangItem;
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use rustc_hir::{GeneratorKind, HirIdMap, Node};
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use rustc_index::vec::{Idx, IndexVec};
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use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
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use rustc_middle::hir::place::PlaceBase as HirPlaceBase;
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use rustc_middle::middle::region;
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use rustc_middle::mir::*;
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use rustc_middle::ty::subst::Subst;
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use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeckResults};
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use rustc_span::symbol::{kw, sym};
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use rustc_span::Span;
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use rustc_target::spec::abi::Abi;
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use rustc_target::spec::PanicStrategy;
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use super::lints;
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crate fn mir_built<'tcx>(
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tcx: TyCtxt<'tcx>,
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def: ty::WithOptConstParam<LocalDefId>,
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) -> &'tcx rustc_data_structures::steal::Steal<Body<'tcx>> {
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if let Some(def) = def.try_upgrade(tcx) {
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return tcx.mir_built(def);
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}
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let mut body = mir_build(tcx, def);
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if def.const_param_did.is_some() {
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assert!(matches!(body.source.instance, ty::InstanceDef::Item(_)));
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body.source = MirSource::from_instance(ty::InstanceDef::Item(def.to_global()));
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}
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tcx.alloc_steal_mir(body)
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}
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/// Construct the MIR for a given `DefId`.
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fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
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let id = tcx.hir().local_def_id_to_hir_id(def.did);
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let body_owner_kind = tcx.hir().body_owner_kind(id);
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let typeck_results = tcx.typeck_opt_const_arg(def);
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// Figure out what primary body this item has.
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let (body_id, return_ty_span, span_with_body) = match tcx.hir().get(id) {
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Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(_, decl, body_id, _, _), .. }) => {
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(*body_id, decl.output.span(), None)
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}
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Node::Item(hir::Item {
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kind: hir::ItemKind::Fn(hir::FnSig { decl, .. }, _, body_id),
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span,
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..
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})
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| Node::ImplItem(hir::ImplItem {
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kind: hir::ImplItemKind::Fn(hir::FnSig { decl, .. }, body_id),
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span,
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..
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})
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| Node::TraitItem(hir::TraitItem {
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kind: hir::TraitItemKind::Fn(hir::FnSig { decl, .. }, hir::TraitFn::Provided(body_id)),
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span,
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..
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}) => {
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// Use the `Span` of the `Item/ImplItem/TraitItem` as the body span,
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// since the def span of a function does not include the body
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(*body_id, decl.output.span(), Some(*span))
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}
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Node::Item(hir::Item {
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kind: hir::ItemKind::Static(ty, _, body_id) | hir::ItemKind::Const(ty, body_id),
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..
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})
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| Node::ImplItem(hir::ImplItem { kind: hir::ImplItemKind::Const(ty, body_id), .. })
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| Node::TraitItem(hir::TraitItem {
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kind: hir::TraitItemKind::Const(ty, Some(body_id)),
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..
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}) => (*body_id, ty.span, None),
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Node::AnonConst(hir::AnonConst { body, hir_id, .. }) => {
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(*body, tcx.hir().span(*hir_id), None)
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}
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_ => span_bug!(tcx.hir().span(id), "can't build MIR for {:?}", def.did),
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};
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// If we don't have a specialized span for the body, just use the
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// normal def span.
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let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
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let arena = Arena::default();
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tcx.infer_ctxt().enter(|infcx| {
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let body = if let Some(ErrorReported) = typeck_results.tainted_by_errors {
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build::construct_error(&infcx, def, id, body_id, body_owner_kind)
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} else if body_owner_kind.is_fn_or_closure() {
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// fetch the fully liberated fn signature (that is, all bound
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// types/lifetimes replaced)
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let fn_sig = typeck_results.liberated_fn_sigs()[id];
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let fn_def_id = tcx.hir().local_def_id(id);
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let safety = match fn_sig.unsafety {
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hir::Unsafety::Normal => Safety::Safe,
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hir::Unsafety::Unsafe => Safety::FnUnsafe,
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};
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let body = tcx.hir().body(body_id);
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let thir = build_thir(tcx, def, &arena, &body.value);
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let ty = tcx.type_of(fn_def_id);
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let mut abi = fn_sig.abi;
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let implicit_argument = match ty.kind() {
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ty::Closure(..) => {
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// HACK(eddyb) Avoid having RustCall on closures,
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// as it adds unnecessary (and wrong) auto-tupling.
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abi = Abi::Rust;
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vec![ArgInfo(liberated_closure_env_ty(tcx, id, body_id), None, None, None)]
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}
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ty::Generator(..) => {
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let gen_ty = tcx.typeck_body(body_id).node_type(id);
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// The resume argument may be missing, in that case we need to provide it here.
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// It will always be `()` in this case.
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if body.params.is_empty() {
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vec![
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ArgInfo(gen_ty, None, None, None),
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ArgInfo(tcx.mk_unit(), None, None, None),
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]
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} else {
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vec![ArgInfo(gen_ty, None, None, None)]
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}
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}
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_ => vec![],
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};
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let explicit_arguments = body.params.iter().enumerate().map(|(index, arg)| {
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let owner_id = tcx.hir().body_owner(body_id);
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let opt_ty_info;
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let self_arg;
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if let Some(ref fn_decl) = tcx.hir().fn_decl_by_hir_id(owner_id) {
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opt_ty_info = fn_decl.inputs.get(index).map(|ty| ty.span);
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self_arg = if index == 0 && fn_decl.implicit_self.has_implicit_self() {
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match fn_decl.implicit_self {
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hir::ImplicitSelfKind::Imm => Some(ImplicitSelfKind::Imm),
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hir::ImplicitSelfKind::Mut => Some(ImplicitSelfKind::Mut),
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hir::ImplicitSelfKind::ImmRef => Some(ImplicitSelfKind::ImmRef),
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hir::ImplicitSelfKind::MutRef => Some(ImplicitSelfKind::MutRef),
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_ => None,
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}
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} else {
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None
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};
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} else {
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opt_ty_info = None;
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self_arg = None;
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}
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// C-variadic fns also have a `VaList` input that's not listed in `fn_sig`
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// (as it's created inside the body itself, not passed in from outside).
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let ty = if fn_sig.c_variadic && index == fn_sig.inputs().len() {
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let va_list_did = tcx.require_lang_item(LangItem::VaList, Some(arg.span));
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tcx.type_of(va_list_did).subst(tcx, &[tcx.lifetimes.re_erased.into()])
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} else {
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fn_sig.inputs()[index]
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};
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ArgInfo(ty, opt_ty_info, Some(&arg), self_arg)
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});
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let arguments = implicit_argument.into_iter().chain(explicit_arguments);
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let (yield_ty, return_ty) = if body.generator_kind.is_some() {
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let gen_ty = tcx.typeck_body(body_id).node_type(id);
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let gen_sig = match gen_ty.kind() {
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ty::Generator(_, gen_substs, ..) => gen_substs.as_generator().sig(),
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_ => span_bug!(tcx.hir().span(id), "generator w/o generator type: {:?}", ty),
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};
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(Some(gen_sig.yield_ty), gen_sig.return_ty)
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} else {
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(None, fn_sig.output())
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};
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let mut mir = build::construct_fn(
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&infcx,
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def,
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id,
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arguments,
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safety,
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abi,
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return_ty,
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return_ty_span,
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body,
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thir,
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span_with_body,
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);
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if yield_ty.is_some() {
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mir.generator.as_mut().unwrap().yield_ty = yield_ty;
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}
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mir
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} else {
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// Get the revealed type of this const. This is *not* the adjusted
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// type of its body, which may be a subtype of this type. For
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// example:
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//
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// fn foo(_: &()) {}
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// static X: fn(&'static ()) = foo;
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//
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// The adjusted type of the body of X is `for<'a> fn(&'a ())` which
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// is not the same as the type of X. We need the type of the return
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// place to be the type of the constant because NLL typeck will
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// equate them.
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let return_ty = typeck_results.node_type(id);
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let ast_expr = &tcx.hir().body(body_id).value;
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let thir = build_thir(tcx, def, &arena, ast_expr);
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build::construct_const(&infcx, thir, def, id, return_ty, return_ty_span)
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};
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lints::check(tcx, &body);
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// The borrow checker will replace all the regions here with its own
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// inference variables. There's no point having non-erased regions here.
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// The exception is `body.user_type_annotations`, which is used unmodified
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// by borrow checking.
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debug_assert!(
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!(body.local_decls.has_free_regions()
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|| body.basic_blocks().has_free_regions()
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|| body.var_debug_info.has_free_regions()
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|| body.yield_ty().has_free_regions()),
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"Unexpected free regions in MIR: {:?}",
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body,
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);
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body
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})
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}
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///////////////////////////////////////////////////////////////////////////
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// BuildMir -- walks a crate, looking for fn items and methods to build MIR from
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fn liberated_closure_env_ty(
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tcx: TyCtxt<'_>,
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closure_expr_id: hir::HirId,
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body_id: hir::BodyId,
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) -> Ty<'_> {
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let closure_ty = tcx.typeck_body(body_id).node_type(closure_expr_id);
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let (closure_def_id, closure_substs) = match *closure_ty.kind() {
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ty::Closure(closure_def_id, closure_substs) => (closure_def_id, closure_substs),
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_ => bug!("closure expr does not have closure type: {:?}", closure_ty),
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};
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let closure_env_ty = tcx.closure_env_ty(closure_def_id, closure_substs).unwrap();
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tcx.erase_late_bound_regions(closure_env_ty)
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}
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#[derive(Debug, PartialEq, Eq)]
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enum BlockFrame {
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/// Evaluation is currently within a statement.
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///
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/// Examples include:
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/// 1. `EXPR;`
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/// 2. `let _ = EXPR;`
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/// 3. `let x = EXPR;`
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Statement {
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/// If true, then statement discards result from evaluating
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/// the expression (such as examples 1 and 2 above).
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ignores_expr_result: bool,
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},
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/// Evaluation is currently within the tail expression of a block.
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///
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/// Example: `{ STMT_1; STMT_2; EXPR }`
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TailExpr {
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/// If true, then the surrounding context of the block ignores
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/// the result of evaluating the block's tail expression.
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///
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/// Example: `let _ = { STMT_1; EXPR };`
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tail_result_is_ignored: bool,
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/// `Span` of the tail expression.
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span: Span,
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},
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/// Generic mark meaning that the block occurred as a subexpression
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/// where the result might be used.
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///
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/// Examples: `foo(EXPR)`, `match EXPR { ... }`
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SubExpr,
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}
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impl BlockFrame {
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fn is_tail_expr(&self) -> bool {
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match *self {
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BlockFrame::TailExpr { .. } => true,
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BlockFrame::Statement { .. } | BlockFrame::SubExpr => false,
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}
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}
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fn is_statement(&self) -> bool {
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match *self {
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BlockFrame::Statement { .. } => true,
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BlockFrame::TailExpr { .. } | BlockFrame::SubExpr => false,
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}
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}
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}
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#[derive(Debug)]
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struct BlockContext(Vec<BlockFrame>);
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struct Builder<'a, 'tcx> {
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tcx: TyCtxt<'tcx>,
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infcx: &'a InferCtxt<'a, 'tcx>,
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typeck_results: &'tcx TypeckResults<'tcx>,
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region_scope_tree: &'tcx region::ScopeTree,
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param_env: ty::ParamEnv<'tcx>,
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cfg: CFG<'tcx>,
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def_id: DefId,
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hir_id: hir::HirId,
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check_overflow: bool,
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fn_span: Span,
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arg_count: usize,
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generator_kind: Option<GeneratorKind>,
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/// The current set of scopes, updated as we traverse;
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/// see the `scope` module for more details.
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scopes: scope::Scopes<'tcx>,
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/// The block-context: each time we build the code within an thir::Block,
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/// we push a frame here tracking whether we are building a statement or
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/// if we are pushing the tail expression of the block. This is used to
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/// embed information in generated temps about whether they were created
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/// for a block tail expression or not.
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///
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/// It would be great if we could fold this into `self.scopes`
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/// somehow, but right now I think that is very tightly tied to
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/// the code generation in ways that we cannot (or should not)
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/// start just throwing new entries onto that vector in order to
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/// distinguish the context of EXPR1 from the context of EXPR2 in
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/// `{ STMTS; EXPR1 } + EXPR2`.
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block_context: BlockContext,
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/// The current unsafe block in scope, even if it is hidden by
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/// a `PushUnsafeBlock`.
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unpushed_unsafe: Safety,
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/// The number of `push_unsafe_block` levels in scope.
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push_unsafe_count: usize,
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/// The vector of all scopes that we have created thus far;
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/// we track this for debuginfo later.
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source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
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source_scope: SourceScope,
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/// The guard-context: each time we build the guard expression for
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/// a match arm, we push onto this stack, and then pop when we
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/// finish building it.
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guard_context: Vec<GuardFrame>,
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/// Maps `HirId`s of variable bindings to the `Local`s created for them.
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/// (A match binding can have two locals; the 2nd is for the arm's guard.)
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var_indices: HirIdMap<LocalsForNode>,
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local_decls: IndexVec<Local, LocalDecl<'tcx>>,
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canonical_user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
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upvar_mutbls: Vec<Mutability>,
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unit_temp: Option<Place<'tcx>>,
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var_debug_info: Vec<VarDebugInfo<'tcx>>,
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}
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impl<'a, 'tcx> Builder<'a, 'tcx> {
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fn is_bound_var_in_guard(&self, id: hir::HirId) -> bool {
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self.guard_context.iter().any(|frame| frame.locals.iter().any(|local| local.id == id))
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}
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fn var_local_id(&self, id: hir::HirId, for_guard: ForGuard) -> Local {
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self.var_indices[&id].local_id(for_guard)
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}
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}
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impl BlockContext {
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fn new() -> Self {
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BlockContext(vec![])
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}
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fn push(&mut self, bf: BlockFrame) {
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self.0.push(bf);
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}
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fn pop(&mut self) -> Option<BlockFrame> {
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self.0.pop()
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}
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/// Traverses the frames on the `BlockContext`, searching for either
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/// the first block-tail expression frame with no intervening
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/// statement frame.
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///
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/// Notably, this skips over `SubExpr` frames; this method is
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/// meant to be used in the context of understanding the
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/// relationship of a temp (created within some complicated
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/// expression) with its containing expression, and whether the
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/// value of that *containing expression* (not the temp!) is
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/// ignored.
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fn currently_in_block_tail(&self) -> Option<BlockTailInfo> {
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for bf in self.0.iter().rev() {
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match bf {
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BlockFrame::SubExpr => continue,
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BlockFrame::Statement { .. } => break,
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&BlockFrame::TailExpr { tail_result_is_ignored, span } => {
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return Some(BlockTailInfo { tail_result_is_ignored, span });
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}
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}
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}
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None
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}
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|
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/// Looks at the topmost frame on the BlockContext and reports
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/// whether its one that would discard a block tail result.
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///
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/// Unlike `currently_within_ignored_tail_expression`, this does
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/// *not* skip over `SubExpr` frames: here, we want to know
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/// whether the block result itself is discarded.
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fn currently_ignores_tail_results(&self) -> bool {
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match self.0.last() {
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// no context: conservatively assume result is read
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None => false,
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// sub-expression: block result feeds into some computation
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Some(BlockFrame::SubExpr) => false,
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// otherwise: use accumulated is_ignored state.
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Some(
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BlockFrame::TailExpr { tail_result_is_ignored: ignored, .. }
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| BlockFrame::Statement { ignores_expr_result: ignored },
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) => *ignored,
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}
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}
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}
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|
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#[derive(Debug)]
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enum LocalsForNode {
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|
/// In the usual case, a `HirId` for an identifier maps to at most
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/// one `Local` declaration.
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One(Local),
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/// The exceptional case is identifiers in a match arm's pattern
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|
/// that are referenced in a guard of that match arm. For these,
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/// we have `2` Locals.
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///
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|
/// * `for_arm_body` is the Local used in the arm body (which is
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/// just like the `One` case above),
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///
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/// * `ref_for_guard` is the Local used in the arm's guard (which
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/// is a reference to a temp that is an alias of
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/// `for_arm_body`).
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ForGuard { ref_for_guard: Local, for_arm_body: Local },
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}
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|
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#[derive(Debug)]
|
|
struct GuardFrameLocal {
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id: hir::HirId,
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}
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|
|
impl GuardFrameLocal {
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|
fn new(id: hir::HirId, _binding_mode: BindingMode) -> Self {
|
|
GuardFrameLocal { 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>>,
|
|
}
|
|
|
|
rustc_index::newtype_index! {
|
|
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: LocalDefId, abi: Abi) -> bool {
|
|
// Validate `#[unwind]` syntax regardless of platform-specific panic strategy.
|
|
let attrs = &tcx.get_attrs(fn_def_id.to_def_id());
|
|
let unwind_attr = attr::find_unwind_attr(&tcx.sess, attrs);
|
|
|
|
// We never unwind, so it's not relevant to stop an unwind.
|
|
if tcx.sess.panic_strategy() != PanicStrategy::Unwind {
|
|
return false;
|
|
}
|
|
|
|
match unwind_attr {
|
|
// If an `#[unwind]` attribute was found, we should adhere to it.
|
|
Some(UnwindAttr::Allowed) => false,
|
|
Some(UnwindAttr::Aborts) => true,
|
|
// If no attribute was found and the panic strategy is `unwind`, then we should examine
|
|
// the function's ABI string to determine whether it should abort upon panic.
|
|
None if tcx.features().c_unwind => {
|
|
use Abi::*;
|
|
match abi {
|
|
// In the case of ABI's that have an `-unwind` equivalent, check whether the ABI
|
|
// permits unwinding. If so, we should not abort. Otherwise, we should.
|
|
C { unwind } | Stdcall { unwind } | System { unwind } | Thiscall { unwind } => {
|
|
!unwind
|
|
}
|
|
// Rust and `rust-call` functions are allowed to unwind, and should not abort.
|
|
Rust | RustCall => false,
|
|
// Other ABI's should abort.
|
|
Cdecl
|
|
| Fastcall
|
|
| Vectorcall
|
|
| Aapcs
|
|
| Win64
|
|
| SysV64
|
|
| PtxKernel
|
|
| Msp430Interrupt
|
|
| X86Interrupt
|
|
| AmdGpuKernel
|
|
| EfiApi
|
|
| AvrInterrupt
|
|
| AvrNonBlockingInterrupt
|
|
| CCmseNonSecureCall
|
|
| RustIntrinsic
|
|
| PlatformIntrinsic
|
|
| Unadjusted => true,
|
|
}
|
|
}
|
|
// If the `c_unwind` feature gate is not active, follow the behavior that was in place
|
|
// prior to #76570. This is a special case: some functions have a C ABI but are meant to
|
|
// unwind anyway. Don't stop them.
|
|
None => false, // FIXME(#58794); should be `!(abi == Abi::Rust || abi == Abi::RustCall)`
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
/// the main entry point for building MIR for a function
|
|
|
|
struct ArgInfo<'tcx>(
|
|
Ty<'tcx>,
|
|
Option<Span>,
|
|
Option<&'tcx hir::Param<'tcx>>,
|
|
Option<ImplicitSelfKind>,
|
|
);
|
|
|
|
fn construct_fn<'tcx, A>(
|
|
infcx: &InferCtxt<'_, 'tcx>,
|
|
fn_def: ty::WithOptConstParam<LocalDefId>,
|
|
fn_id: hir::HirId,
|
|
arguments: A,
|
|
safety: Safety,
|
|
abi: Abi,
|
|
return_ty: Ty<'tcx>,
|
|
return_ty_span: Span,
|
|
body: &'tcx hir::Body<'tcx>,
|
|
expr: &Expr<'_, 'tcx>,
|
|
span_with_body: Span,
|
|
) -> Body<'tcx>
|
|
where
|
|
A: Iterator<Item = ArgInfo<'tcx>>,
|
|
{
|
|
let arguments: Vec<_> = arguments.collect();
|
|
|
|
let tcx = infcx.tcx;
|
|
let span = tcx.hir().span(fn_id);
|
|
|
|
let mut builder = Builder::new(
|
|
infcx,
|
|
fn_def,
|
|
fn_id,
|
|
span_with_body,
|
|
arguments.len(),
|
|
safety,
|
|
return_ty,
|
|
return_ty_span,
|
|
body.generator_kind,
|
|
);
|
|
|
|
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 source_info = builder.source_info(span);
|
|
let call_site_s = (call_site_scope, source_info);
|
|
unpack!(builder.in_scope(call_site_s, LintLevel::Inherited, |builder| {
|
|
let arg_scope_s = (arg_scope, source_info);
|
|
// Attribute epilogue to function's closing brace
|
|
let fn_end = span_with_body.shrink_to_hi();
|
|
let return_block =
|
|
unpack!(builder.in_breakable_scope(None, Place::return_place(), fn_end, |builder| {
|
|
Some(builder.in_scope(arg_scope_s, LintLevel::Inherited, |builder| {
|
|
builder.args_and_body(
|
|
START_BLOCK,
|
|
fn_def.did.to_def_id(),
|
|
&arguments,
|
|
arg_scope,
|
|
expr,
|
|
)
|
|
}))
|
|
}));
|
|
let source_info = builder.source_info(fn_end);
|
|
builder.cfg.terminate(return_block, source_info, TerminatorKind::Return);
|
|
let should_abort = should_abort_on_panic(tcx, fn_def.did, abi);
|
|
builder.build_drop_trees(should_abort);
|
|
return_block.unit()
|
|
}));
|
|
|
|
let spread_arg = if abi == Abi::RustCall {
|
|
// RustCall pseudo-ABI untuples the last argument.
|
|
Some(Local::new(arguments.len()))
|
|
} else {
|
|
None
|
|
};
|
|
debug!("fn_id {:?} has attrs {:?}", fn_def, tcx.get_attrs(fn_def.did.to_def_id()));
|
|
|
|
let mut body = builder.finish();
|
|
body.spread_arg = spread_arg;
|
|
body
|
|
}
|
|
|
|
fn construct_const<'a, 'tcx>(
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
expr: &Expr<'_, 'tcx>,
|
|
def: ty::WithOptConstParam<LocalDefId>,
|
|
hir_id: hir::HirId,
|
|
const_ty: Ty<'tcx>,
|
|
const_ty_span: Span,
|
|
) -> Body<'tcx> {
|
|
let tcx = infcx.tcx;
|
|
let span = tcx.hir().span(hir_id);
|
|
let mut builder =
|
|
Builder::new(infcx, def, hir_id, span, 0, Safety::Safe, const_ty, const_ty_span, None);
|
|
|
|
let mut block = START_BLOCK;
|
|
unpack!(block = builder.expr_into_dest(Place::return_place(), block, &expr));
|
|
|
|
let source_info = builder.source_info(span);
|
|
builder.cfg.terminate(block, source_info, TerminatorKind::Return);
|
|
|
|
builder.build_drop_trees(false);
|
|
|
|
builder.finish()
|
|
}
|
|
|
|
/// Construct MIR for a item that has had errors in type checking.
|
|
///
|
|
/// This is required because we may still want to run MIR passes on an item
|
|
/// with type errors, but normal MIR construction can't handle that in general.
|
|
fn construct_error<'a, 'tcx>(
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
def: ty::WithOptConstParam<LocalDefId>,
|
|
hir_id: hir::HirId,
|
|
body_id: hir::BodyId,
|
|
body_owner_kind: hir::BodyOwnerKind,
|
|
) -> Body<'tcx> {
|
|
let tcx = infcx.tcx;
|
|
let span = tcx.hir().span(hir_id);
|
|
let ty = tcx.ty_error();
|
|
let generator_kind = tcx.hir().body(body_id).generator_kind;
|
|
let num_params = match body_owner_kind {
|
|
hir::BodyOwnerKind::Fn => tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len(),
|
|
hir::BodyOwnerKind::Closure => {
|
|
if generator_kind.is_some() {
|
|
// Generators have an implicit `self` parameter *and* a possibly
|
|
// implicit resume parameter.
|
|
2
|
|
} else {
|
|
// The implicit self parameter adds another local in MIR.
|
|
1 + tcx.hir().fn_decl_by_hir_id(hir_id).unwrap().inputs.len()
|
|
}
|
|
}
|
|
hir::BodyOwnerKind::Const => 0,
|
|
hir::BodyOwnerKind::Static(_) => 0,
|
|
};
|
|
let mut builder =
|
|
Builder::new(infcx, def, hir_id, span, num_params, Safety::Safe, ty, span, generator_kind);
|
|
let source_info = builder.source_info(span);
|
|
// Some MIR passes will expect the number of parameters to match the
|
|
// function declaration.
|
|
for _ in 0..num_params {
|
|
builder.local_decls.push(LocalDecl::with_source_info(ty, source_info));
|
|
}
|
|
builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable);
|
|
let mut body = builder.finish();
|
|
body.generator.as_mut().map(|gen| gen.yield_ty = Some(ty));
|
|
body
|
|
}
|
|
|
|
impl<'a, 'tcx> Builder<'a, 'tcx> {
|
|
fn new(
|
|
infcx: &'a InferCtxt<'a, 'tcx>,
|
|
def: ty::WithOptConstParam<LocalDefId>,
|
|
hir_id: hir::HirId,
|
|
span: Span,
|
|
arg_count: usize,
|
|
safety: Safety,
|
|
return_ty: Ty<'tcx>,
|
|
return_span: Span,
|
|
generator_kind: Option<GeneratorKind>,
|
|
) -> Builder<'a, 'tcx> {
|
|
let tcx = infcx.tcx;
|
|
let attrs = tcx.hir().attrs(hir_id);
|
|
// Some functions always have overflow checks enabled,
|
|
// however, they may not get codegen'd, depending on
|
|
// the settings for the crate they are codegened in.
|
|
let mut check_overflow = tcx.sess.contains_name(attrs, sym::rustc_inherit_overflow_checks);
|
|
// Respect -C overflow-checks.
|
|
check_overflow |= tcx.sess.overflow_checks();
|
|
// Constants always need overflow checks.
|
|
check_overflow |= matches!(
|
|
tcx.hir().body_owner_kind(hir_id),
|
|
hir::BodyOwnerKind::Const | hir::BodyOwnerKind::Static(_)
|
|
);
|
|
|
|
let lint_level = LintLevel::Explicit(hir_id);
|
|
let mut builder = Builder {
|
|
tcx,
|
|
infcx,
|
|
typeck_results: tcx.typeck_opt_const_arg(def),
|
|
region_scope_tree: tcx.region_scope_tree(def.did),
|
|
param_env: tcx.param_env(def.did),
|
|
def_id: def.did.to_def_id(),
|
|
hir_id,
|
|
check_overflow,
|
|
cfg: CFG { basic_blocks: IndexVec::new() },
|
|
fn_span: span,
|
|
arg_count,
|
|
generator_kind,
|
|
scopes: scope::Scopes::new(),
|
|
block_context: BlockContext::new(),
|
|
source_scopes: IndexVec::new(),
|
|
source_scope: OUTERMOST_SOURCE_SCOPE,
|
|
guard_context: vec![],
|
|
push_unsafe_count: 0,
|
|
unpushed_unsafe: safety,
|
|
local_decls: IndexVec::from_elem_n(LocalDecl::new(return_ty, return_span), 1),
|
|
canonical_user_type_annotations: IndexVec::new(),
|
|
upvar_mutbls: vec![],
|
|
var_indices: Default::default(),
|
|
unit_temp: None,
|
|
var_debug_info: vec![],
|
|
};
|
|
|
|
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) -> 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(
|
|
MirSource::item(self.def_id),
|
|
self.cfg.basic_blocks,
|
|
self.source_scopes,
|
|
self.local_decls,
|
|
self.canonical_user_type_annotations,
|
|
self.arg_count,
|
|
self.var_debug_info,
|
|
self.fn_span,
|
|
self.generator_kind,
|
|
)
|
|
}
|
|
|
|
fn args_and_body(
|
|
&mut self,
|
|
mut block: BasicBlock,
|
|
fn_def_id: DefId,
|
|
arguments: &[ArgInfo<'tcx>],
|
|
argument_scope: region::Scope,
|
|
expr: &Expr<'_, 'tcx>,
|
|
) -> BlockAnd<()> {
|
|
// Allocate locals for the function arguments
|
|
for &ArgInfo(ty, _, arg_opt, _) in arguments.iter() {
|
|
let source_info =
|
|
SourceInfo::outermost(arg_opt.map_or(self.fn_span, |arg| arg.pat.span));
|
|
let arg_local = self.local_decls.push(LocalDecl::with_source_info(ty, source_info));
|
|
|
|
// If this is a simple binding pattern, give debuginfo a nice name.
|
|
if let Some(arg) = arg_opt {
|
|
if let Some(ident) = arg.pat.simple_ident() {
|
|
self.var_debug_info.push(VarDebugInfo {
|
|
name: ident.name,
|
|
source_info,
|
|
value: VarDebugInfoContents::Place(arg_local.into()),
|
|
});
|
|
}
|
|
}
|
|
}
|
|
|
|
let tcx = self.tcx;
|
|
let tcx_hir = tcx.hir();
|
|
let hir_typeck_results = self.typeck_results;
|
|
|
|
// In analyze_closure() in upvar.rs we gathered a list of upvars used by a
|
|
// indexed closure and we stored in a map called closure_min_captures in TypeckResults
|
|
// with the closure's DefId. Here, we run through that vec of UpvarIds for
|
|
// the given closure and use the necessary information to create upvar
|
|
// debuginfo and to fill `self.upvar_mutbls`.
|
|
if hir_typeck_results.closure_min_captures.get(&fn_def_id).is_some() {
|
|
let closure_env_arg = Local::new(1);
|
|
let mut closure_env_projs = vec![];
|
|
let mut closure_ty = self.local_decls[closure_env_arg].ty;
|
|
if let ty::Ref(_, ty, _) = closure_ty.kind() {
|
|
closure_env_projs.push(ProjectionElem::Deref);
|
|
closure_ty = ty;
|
|
}
|
|
let upvar_substs = match closure_ty.kind() {
|
|
ty::Closure(_, substs) => ty::UpvarSubsts::Closure(substs),
|
|
ty::Generator(_, substs, _) => ty::UpvarSubsts::Generator(substs),
|
|
_ => span_bug!(self.fn_span, "upvars with non-closure env ty {:?}", closure_ty),
|
|
};
|
|
let capture_tys = upvar_substs.upvar_tys();
|
|
let captures_with_tys =
|
|
hir_typeck_results.closure_min_captures_flattened(fn_def_id).zip(capture_tys);
|
|
|
|
self.upvar_mutbls = captures_with_tys
|
|
.enumerate()
|
|
.map(|(i, (captured_place, ty))| {
|
|
let capture = captured_place.info.capture_kind;
|
|
let var_id = match captured_place.place.base {
|
|
HirPlaceBase::Upvar(upvar_id) => upvar_id.var_path.hir_id,
|
|
_ => bug!("Expected an upvar"),
|
|
};
|
|
|
|
let mutability = captured_place.mutability;
|
|
|
|
// FIXME(project-rfc-2229#8): Store more precise information
|
|
let mut name = kw::Empty;
|
|
if let Some(Node::Binding(pat)) = tcx_hir.find(var_id) {
|
|
if let hir::PatKind::Binding(_, _, ident, _) = pat.kind {
|
|
name = ident.name;
|
|
}
|
|
}
|
|
|
|
let mut projs = closure_env_projs.clone();
|
|
projs.push(ProjectionElem::Field(Field::new(i), ty));
|
|
match capture {
|
|
ty::UpvarCapture::ByValue(_) => {}
|
|
ty::UpvarCapture::ByRef(..) => {
|
|
projs.push(ProjectionElem::Deref);
|
|
}
|
|
};
|
|
|
|
self.var_debug_info.push(VarDebugInfo {
|
|
name,
|
|
source_info: SourceInfo::outermost(tcx_hir.span(var_id)),
|
|
value: VarDebugInfoContents::Place(Place {
|
|
local: closure_env_arg,
|
|
projection: tcx.intern_place_elems(&projs),
|
|
}),
|
|
});
|
|
|
|
mutability
|
|
})
|
|
.collect();
|
|
}
|
|
|
|
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(_, 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(expr.span, |arg| arg.pat.span),
|
|
argument_scope,
|
|
local,
|
|
DropKind::Value,
|
|
);
|
|
|
|
if let Some(arg) = arg_opt {
|
|
let pat = match tcx.hir().get(arg.pat.hir_id) {
|
|
Node::Pat(pat) | Node::Binding(pat) => pat,
|
|
node => bug!("pattern became {:?}", node),
|
|
};
|
|
let pattern = Pat::from_hir(tcx, self.param_env, self.typeck_results, 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
|
|
PatKind::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].local_info = if let Some(kind) = self_binding {
|
|
Some(box LocalInfo::User(ClearCrossCrate::Set(
|
|
BindingForm::ImplicitSelf(*kind),
|
|
)))
|
|
} else {
|
|
let binding_mode = ty::BindingMode::BindByValue(mutability);
|
|
Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(
|
|
VarBindingForm {
|
|
binding_mode,
|
|
opt_ty_info,
|
|
opt_match_place: Some((Some(place), span)),
|
|
pat_span: span,
|
|
},
|
|
))))
|
|
};
|
|
self.var_indices.insert(var, LocalsForNode::One(local));
|
|
}
|
|
_ => {
|
|
scope = self.declare_bindings(
|
|
scope,
|
|
expr.span,
|
|
&pattern,
|
|
matches::ArmHasGuard(false),
|
|
Some((Some(&place), span)),
|
|
);
|
|
let place_builder = PlaceBuilder::from(local);
|
|
unpack!(
|
|
block = self.place_into_pattern(block, pattern, place_builder, 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;
|
|
}
|
|
|
|
self.expr_into_dest(Place::return_place(), block, &expr)
|
|
}
|
|
|
|
fn set_correct_source_scope_for_arg(
|
|
&mut self,
|
|
arg_hir_id: hir::HirId,
|
|
original_source_scope: SourceScope,
|
|
pattern_span: Span,
|
|
) {
|
|
let tcx = self.tcx;
|
|
let current_root = tcx.maybe_lint_level_root_bounded(arg_hir_id, self.hir_id);
|
|
let parent_root = tcx.maybe_lint_level_root_bounded(
|
|
self.source_scopes[original_source_scope]
|
|
.local_data
|
|
.as_ref()
|
|
.assert_crate_local()
|
|
.lint_root,
|
|
self.hir_id,
|
|
);
|
|
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(tmp) => tmp,
|
|
None => {
|
|
let ty = self.tcx.mk_unit();
|
|
let fn_span = self.fn_span;
|
|
let tmp = self.temp(ty, fn_span);
|
|
self.unit_temp = Some(tmp);
|
|
tmp
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// 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 matches;
|
|
mod misc;
|
|
mod scope;
|