| // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| |
| use build; |
| use hair::cx::Cx; |
| use hair::LintLevel; |
| use rustc::hir; |
| use rustc::hir::def_id::DefId; |
| use rustc::middle::region; |
| use rustc::mir::*; |
| use rustc::mir::transform::MirSource; |
| use rustc::mir::visit::{MutVisitor, Lookup}; |
| use rustc::ty::{self, Ty, TyCtxt}; |
| use rustc::ty::subst::Substs; |
| use rustc::util::nodemap::NodeMap; |
| use rustc_data_structures::indexed_vec::{IndexVec, Idx}; |
| use shim; |
| use std::mem; |
| use std::u32; |
| use syntax::abi::Abi; |
| use syntax::ast; |
| use syntax::symbol::keywords; |
| use syntax_pos::Span; |
| use util as mir_util; |
| |
| /// Construct the MIR for a given def-id. |
| pub fn mir_build<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> Mir<'tcx> { |
| let id = tcx.hir.as_local_node_id(def_id).unwrap(); |
| let unsupported = || { |
| span_bug!(tcx.hir.span(id), "can't build MIR for {:?}", def_id); |
| }; |
| |
| // Figure out what primary body this item has. |
| let body_id = match tcx.hir.get(id) { |
| hir::map::NodeItem(item) => { |
| match item.node { |
| hir::ItemConst(_, body) | |
| hir::ItemStatic(_, _, body) | |
| hir::ItemFn(.., body) => body, |
| _ => unsupported() |
| } |
| } |
| hir::map::NodeTraitItem(item) => { |
| match item.node { |
| hir::TraitItemKind::Const(_, Some(body)) | |
| hir::TraitItemKind::Method(_, |
| hir::TraitMethod::Provided(body)) => body, |
| _ => unsupported() |
| } |
| } |
| hir::map::NodeImplItem(item) => { |
| match item.node { |
| hir::ImplItemKind::Const(_, body) | |
| hir::ImplItemKind::Method(_, body) => body, |
| _ => unsupported() |
| } |
| } |
| hir::map::NodeExpr(expr) => { |
| // FIXME(eddyb) Closures should have separate |
| // function definition IDs and expression IDs. |
| // Type-checking should not let closures get |
| // this far in a constant position. |
| // Assume that everything other than closures |
| // is a constant "initializer" expression. |
| match expr.node { |
| hir::ExprClosure(_, _, body, _, _) => body, |
| _ => hir::BodyId { node_id: expr.id }, |
| } |
| } |
| hir::map::NodeVariant(variant) => |
| return create_constructor_shim(tcx, id, &variant.node.data), |
| hir::map::NodeStructCtor(ctor) => |
| return create_constructor_shim(tcx, id, ctor), |
| _ => unsupported(), |
| }; |
| |
| let src = MirSource::from_node(tcx, id); |
| tcx.infer_ctxt().enter(|infcx| { |
| let cx = Cx::new(&infcx, src); |
| let mut mir = if cx.tables().tainted_by_errors { |
| build::construct_error(cx, body_id) |
| } else if let MirSource::Fn(id) = src { |
| // fetch the fully liberated fn signature (that is, all bound |
| // types/lifetimes replaced) |
| let fn_hir_id = tcx.hir.node_to_hir_id(id); |
| let fn_sig = cx.tables().liberated_fn_sigs()[fn_hir_id].clone(); |
| |
| let ty = tcx.type_of(tcx.hir.local_def_id(id)); |
| let mut abi = fn_sig.abi; |
| let implicit_argument = match ty.sty { |
| ty::TyClosure(..) => { |
| // HACK(eddyb) Avoid having RustCall on closures, |
| // as it adds unnecessary (and wrong) auto-tupling. |
| abi = Abi::Rust; |
| Some((closure_self_ty(tcx, id, body_id), None)) |
| } |
| ty::TyGenerator(..) => { |
| let gen_ty = tcx.body_tables(body_id).node_id_to_type(fn_hir_id); |
| Some((gen_ty, None)) |
| } |
| _ => None, |
| }; |
| |
| // FIXME: safety in closures |
| 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.arguments |
| .iter() |
| .enumerate() |
| .map(|(index, arg)| { |
| (fn_sig.inputs()[index], Some(&*arg.pat)) |
| }); |
| |
| let arguments = implicit_argument.into_iter().chain(explicit_arguments); |
| |
| let (yield_ty, return_ty) = if body.is_generator { |
| let gen_sig = cx.tables().generator_sigs()[fn_hir_id].clone().unwrap(); |
| (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, body) |
| } else { |
| build::construct_const(cx, body_id) |
| }; |
| |
| // Convert the Mir to global types. |
| let mut globalizer = GlobalizeMir { |
| tcx, |
| span: mir.span |
| }; |
| globalizer.visit_mir(&mut mir); |
| let mir = unsafe { |
| mem::transmute::<Mir, Mir<'tcx>>(mir) |
| }; |
| |
| mir_util::dump_mir(tcx, None, "mir_map", &0, src, &mir, |_, _| Ok(()) ); |
| |
| mir |
| }) |
| } |
| |
| /// A pass to lift all the types and substitutions in a Mir |
| /// to the global tcx. Sadly, we don't have a "folder" that |
| /// can change 'tcx so we have to transmute afterwards. |
| struct GlobalizeMir<'a, 'gcx: 'a> { |
| tcx: TyCtxt<'a, 'gcx, 'gcx>, |
| span: Span |
| } |
| |
| impl<'a, 'gcx: 'tcx, 'tcx> MutVisitor<'tcx> for GlobalizeMir<'a, 'gcx> { |
| fn visit_ty(&mut self, ty: &mut Ty<'tcx>, _: Lookup) { |
| if let Some(lifted) = self.tcx.lift(ty) { |
| *ty = lifted; |
| } else { |
| span_bug!(self.span, |
| "found type `{:?}` with inference types/regions in MIR", |
| ty); |
| } |
| } |
| |
| fn visit_region(&mut self, region: &mut ty::Region<'tcx>, _: Location) { |
| if let Some(lifted) = self.tcx.lift(region) { |
| *region = lifted; |
| } else { |
| span_bug!(self.span, |
| "found region `{:?}` with inference types/regions in MIR", |
| region); |
| } |
| } |
| |
| fn visit_const(&mut self, constant: &mut &'tcx ty::Const<'tcx>, _: Location) { |
| if let Some(lifted) = self.tcx.lift(constant) { |
| *constant = lifted; |
| } else { |
| span_bug!(self.span, |
| "found constant `{:?}` with inference types/regions in MIR", |
| constant); |
| } |
| } |
| |
| fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>, _: Location) { |
| if let Some(lifted) = self.tcx.lift(substs) { |
| *substs = lifted; |
| } else { |
| span_bug!(self.span, |
| "found substs `{:?}` with inference types/regions in MIR", |
| substs); |
| } |
| } |
| } |
| |
| fn create_constructor_shim<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| ctor_id: ast::NodeId, |
| v: &'tcx hir::VariantData) |
| -> Mir<'tcx> |
| { |
| let span = tcx.hir.span(ctor_id); |
| if let hir::VariantData::Tuple(ref fields, ctor_id) = *v { |
| tcx.infer_ctxt().enter(|infcx| { |
| let (mut mir, src) = |
| shim::build_adt_ctor(&infcx, ctor_id, fields, span); |
| |
| // Convert the Mir to global types. |
| let tcx = infcx.tcx.global_tcx(); |
| let mut globalizer = GlobalizeMir { |
| tcx, |
| span: mir.span |
| }; |
| globalizer.visit_mir(&mut mir); |
| let mir = unsafe { |
| mem::transmute::<Mir, Mir<'tcx>>(mir) |
| }; |
| |
| mir_util::dump_mir(tcx, None, "mir_map", &0, src, &mir, |_, _| Ok(()) ); |
| |
| mir |
| }) |
| } else { |
| span_bug!(span, "attempting to create MIR for non-tuple variant {:?}", v); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // BuildMir -- walks a crate, looking for fn items and methods to build MIR from |
| |
| pub fn closure_self_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, |
| closure_expr_id: ast::NodeId, |
| body_id: hir::BodyId) |
| -> Ty<'tcx> { |
| let closure_expr_hir_id = tcx.hir.node_to_hir_id(closure_expr_id); |
| let closure_ty = tcx.body_tables(body_id).node_id_to_type(closure_expr_hir_id); |
| |
| let closure_def_id = tcx.hir.local_def_id(closure_expr_id); |
| let region = ty::ReFree(ty::FreeRegion { |
| scope: closure_def_id, |
| bound_region: ty::BoundRegion::BrEnv, |
| }); |
| let region = tcx.mk_region(region); |
| |
| match tcx.closure_kind(closure_def_id) { |
| ty::ClosureKind::Fn => |
| tcx.mk_ref(region, |
| ty::TypeAndMut { ty: closure_ty, |
| mutbl: hir::MutImmutable }), |
| ty::ClosureKind::FnMut => |
| tcx.mk_ref(region, |
| ty::TypeAndMut { ty: closure_ty, |
| mutbl: hir::MutMutable }), |
| ty::ClosureKind::FnOnce => |
| closure_ty |
| } |
| } |
| |
| struct Builder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { |
| hir: Cx<'a, 'gcx, 'tcx>, |
| cfg: CFG<'tcx>, |
| |
| fn_span: Span, |
| arg_count: usize, |
| |
| /// the current set of scopes, updated as we traverse; |
| /// see the `scope` module for more details |
| scopes: Vec<scope::Scope<'tcx>>, |
| |
| /// 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 current set of breakables; see the `scope` module for more |
| /// details |
| breakable_scopes: Vec<scope::BreakableScope<'tcx>>, |
| |
| /// the vector of all scopes that we have created thus far; |
| /// we track this for debuginfo later |
| visibility_scopes: IndexVec<VisibilityScope, VisibilityScopeData>, |
| visibility_scope_info: IndexVec<VisibilityScope, VisibilityScopeInfo>, |
| visibility_scope: VisibilityScope, |
| |
| /// Maps node ids of variable bindings to the `Local`s created for them. |
| var_indices: NodeMap<Local>, |
| local_decls: IndexVec<Local, LocalDecl<'tcx>>, |
| unit_temp: Option<Lvalue<'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>, |
| } |
| |
| struct CFG<'tcx> { |
| basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>, |
| } |
| |
| newtype_index!(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 |
| } |
| }; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| /// the main entry point for building MIR for a function |
| |
| fn construct_fn<'a, 'gcx, 'tcx, A>(hir: Cx<'a, 'gcx, 'tcx>, |
| fn_id: ast::NodeId, |
| arguments: A, |
| safety: Safety, |
| abi: Abi, |
| return_ty: Ty<'gcx>, |
| yield_ty: Option<Ty<'gcx>>, |
| body: &'gcx hir::Body) |
| -> Mir<'tcx> |
| where A: Iterator<Item=(Ty<'gcx>, Option<&'gcx hir::Pat>)> |
| { |
| let arguments: Vec<_> = arguments.collect(); |
| |
| let tcx = hir.tcx(); |
| let span = tcx.hir.span(fn_id); |
| let mut builder = Builder::new(hir.clone(), |
| span, |
| arguments.len(), |
| safety, |
| return_ty); |
| |
| let call_site_scope = region::Scope::CallSite(body.value.hir_id.local_id); |
| let arg_scope = region::Scope::Arguments(body.value.hir_id.local_id); |
| 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, block, |builder| { |
| let arg_scope_s = (arg_scope, source_info); |
| unpack!(block = builder.in_scope(arg_scope_s, LintLevel::Inherited, block, |builder| { |
| builder.args_and_body(block, &arguments, arg_scope, &body.value) |
| })); |
| // Attribute epilogue to function's closing brace |
| let fn_end = span.with_lo(span.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); |
| 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())); |
| } |
| |
| // Gather the upvars of a closure, if any. |
| let upvar_decls: Vec<_> = tcx.with_freevars(fn_id, |freevars| { |
| freevars.iter().map(|fv| { |
| let var_id = fv.var_id(); |
| let var_hir_id = tcx.hir.node_to_hir_id(var_id); |
| let closure_expr_id = tcx.hir.local_def_id(fn_id).index; |
| let capture = hir.tables().upvar_capture(ty::UpvarId { |
| var_id: var_hir_id, |
| closure_expr_id, |
| }); |
| let by_ref = match capture { |
| ty::UpvarCapture::ByValue => false, |
| ty::UpvarCapture::ByRef(..) => true |
| }; |
| let mut decl = UpvarDecl { |
| debug_name: keywords::Invalid.name(), |
| by_ref, |
| }; |
| if let Some(hir::map::NodeBinding(pat)) = tcx.hir.find(var_id) { |
| if let hir::PatKind::Binding(_, _, ref ident, _) = pat.node { |
| decl.debug_name = ident.node; |
| } |
| } |
| decl |
| }).collect() |
| }); |
| |
| let mut mir = builder.finish(upvar_decls, return_ty, yield_ty); |
| mir.spread_arg = spread_arg; |
| mir |
| } |
| |
| fn construct_const<'a, 'gcx, 'tcx>(hir: Cx<'a, 'gcx, 'tcx>, |
| body_id: hir::BodyId) |
| -> Mir<'tcx> { |
| let tcx = hir.tcx(); |
| let ast_expr = &tcx.hir.body(body_id).value; |
| let ty = hir.tables().expr_ty_adjusted(ast_expr); |
| let owner_id = tcx.hir.body_owner(body_id); |
| let span = tcx.hir.span(owner_id); |
| let mut builder = Builder::new(hir.clone(), span, 0, Safety::Safe, ty); |
| |
| let mut block = START_BLOCK; |
| let expr = builder.hir.mirror(ast_expr); |
| unpack!(block = builder.into_expr(&Lvalue::Local(RETURN_POINTER), 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); |
| |
| builder.finish(vec![], ty, None) |
| } |
| |
| fn construct_error<'a, 'gcx, 'tcx>(hir: Cx<'a, 'gcx, 'tcx>, |
| body_id: hir::BodyId) |
| -> Mir<'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); |
| let source_info = builder.source_info(span); |
| builder.cfg.terminate(START_BLOCK, source_info, TerminatorKind::Unreachable); |
| builder.finish(vec![], ty, None) |
| } |
| |
| impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { |
| fn new(hir: Cx<'a, 'gcx, 'tcx>, |
| span: Span, |
| arg_count: usize, |
| safety: Safety, |
| return_ty: Ty<'tcx>) |
| -> Builder<'a, 'gcx, '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, |
| scopes: vec![], |
| visibility_scopes: IndexVec::new(), |
| visibility_scope: ARGUMENT_VISIBILITY_SCOPE, |
| visibility_scope_info: IndexVec::new(), |
| push_unsafe_count: 0, |
| unpushed_unsafe: safety, |
| breakable_scopes: vec![], |
| local_decls: IndexVec::from_elem_n(LocalDecl::new_return_pointer(return_ty, |
| span), 1), |
| var_indices: NodeMap(), |
| unit_temp: None, |
| cached_resume_block: None, |
| cached_return_block: None |
| }; |
| |
| assert_eq!(builder.cfg.start_new_block(), START_BLOCK); |
| assert_eq!( |
| builder.new_visibility_scope(span, lint_level, Some(safety)), |
| ARGUMENT_VISIBILITY_SCOPE); |
| builder.visibility_scopes[ARGUMENT_VISIBILITY_SCOPE].parent_scope = None; |
| |
| builder |
| } |
| |
| fn finish(self, |
| upvar_decls: Vec<UpvarDecl>, |
| return_ty: Ty<'tcx>, |
| yield_ty: Option<Ty<'tcx>>) |
| -> Mir<'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); |
| } |
| } |
| |
| Mir::new(self.cfg.basic_blocks, |
| self.visibility_scopes, |
| ClearOnDecode::Set(self.visibility_scope_info), |
| IndexVec::new(), |
| return_ty, |
| yield_ty, |
| self.local_decls, |
| self.arg_count, |
| upvar_decls, |
| self.fn_span |
| ) |
| } |
| |
| fn args_and_body(&mut self, |
| mut block: BasicBlock, |
| arguments: &[(Ty<'gcx>, Option<&'gcx hir::Pat>)], |
| argument_scope: region::Scope, |
| ast_body: &'gcx hir::Expr) |
| -> BlockAnd<()> |
| { |
| // Allocate locals for the function arguments |
| for &(ty, pattern) in arguments.iter() { |
| // If this is a simple binding pattern, give the local a nice name for debuginfo. |
| let mut name = None; |
| if let Some(pat) = pattern { |
| if let hir::PatKind::Binding(_, _, ref ident, _) = pat.node { |
| name = Some(ident.node); |
| } |
| } |
| |
| self.local_decls.push(LocalDecl { |
| mutability: Mutability::Not, |
| ty, |
| source_info: SourceInfo { |
| scope: ARGUMENT_VISIBILITY_SCOPE, |
| span: pattern.map_or(self.fn_span, |pat| pat.span) |
| }, |
| lexical_scope: ARGUMENT_VISIBILITY_SCOPE, |
| name, |
| internal: false, |
| is_user_variable: false, |
| }); |
| } |
| |
| let mut scope = None; |
| // Bind the argument patterns |
| for (index, &(ty, pattern)) in arguments.iter().enumerate() { |
| // Function arguments always get the first Local indices after the return pointer |
| let lvalue = Lvalue::Local(Local::new(index + 1)); |
| |
| if let Some(pattern) = pattern { |
| let pattern = self.hir.pattern_from_hir(pattern); |
| scope = self.declare_bindings(scope, ast_body.span, |
| LintLevel::Inherited, &pattern); |
| unpack!(block = self.lvalue_into_pattern(block, pattern, &lvalue)); |
| } |
| |
| // Make sure we drop (parts of) the argument even when not matched on. |
| self.schedule_drop(pattern.as_ref().map_or(ast_body.span, |pat| pat.span), |
| argument_scope, &lvalue, ty); |
| |
| } |
| |
| // Enter the argument pattern bindings visibility scope, if it exists. |
| if let Some(visibility_scope) = scope { |
| self.visibility_scope = visibility_scope; |
| } |
| |
| let body = self.hir.mirror(ast_body); |
| self.into(&Lvalue::Local(RETURN_POINTER), block, body) |
| } |
| |
| fn get_unit_temp(&mut self) -> Lvalue<'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 translated. Note that they use the `unpack` macro |
| // above extensively. |
| |
| mod block; |
| mod cfg; |
| mod expr; |
| mod into; |
| mod matches; |
| mod misc; |
| mod scope; |
