| // 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 dep_graph::DepNode; |
| use hir::def::Def; |
| use hir::def_id::DefId; |
| use infer::InferCtxt; |
| use traits::ProjectionMode; |
| use ty::{self, Ty, TyCtxt}; |
| use ty::layout::{LayoutError, Pointer, SizeSkeleton}; |
| |
| use syntax::abi::Abi::RustIntrinsic; |
| use syntax::ast; |
| use syntax_pos::Span; |
| use hir::intravisit::{self, Visitor, FnKind}; |
| use hir; |
| |
| pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) { |
| let mut visitor = ItemVisitor { |
| tcx: tcx |
| }; |
| tcx.visit_all_items_in_krate(DepNode::IntrinsicCheck, &mut visitor); |
| } |
| |
| struct ItemVisitor<'a, 'tcx: 'a> { |
| tcx: TyCtxt<'a, 'tcx, 'tcx> |
| } |
| |
| impl<'a, 'tcx> ItemVisitor<'a, 'tcx> { |
| fn visit_const(&mut self, item_id: ast::NodeId, expr: &hir::Expr) { |
| let param_env = ty::ParameterEnvironment::for_item(self.tcx, item_id); |
| self.tcx.infer_ctxt(None, Some(param_env), ProjectionMode::Any).enter(|infcx| { |
| let mut visitor = ExprVisitor { |
| infcx: &infcx |
| }; |
| visitor.visit_expr(expr); |
| }); |
| } |
| } |
| |
| struct ExprVisitor<'a, 'gcx: 'a+'tcx, 'tcx: 'a> { |
| infcx: &'a InferCtxt<'a, 'gcx, 'tcx> |
| } |
| |
| impl<'a, 'gcx, 'tcx> ExprVisitor<'a, 'gcx, 'tcx> { |
| fn def_id_is_transmute(&self, def_id: DefId) -> bool { |
| let intrinsic = match self.infcx.tcx.lookup_item_type(def_id).ty.sty { |
| ty::TyFnDef(_, _, ref bfty) => bfty.abi == RustIntrinsic, |
| _ => return false |
| }; |
| intrinsic && self.infcx.tcx.item_name(def_id).as_str() == "transmute" |
| } |
| |
| fn check_transmute(&self, span: Span, from: Ty<'gcx>, to: Ty<'gcx>, id: ast::NodeId) { |
| let sk_from = SizeSkeleton::compute(from, self.infcx); |
| let sk_to = SizeSkeleton::compute(to, self.infcx); |
| |
| // Check for same size using the skeletons. |
| if let (Ok(sk_from), Ok(sk_to)) = (sk_from, sk_to) { |
| if sk_from.same_size(sk_to) { |
| return; |
| } |
| |
| match (&from.sty, sk_to) { |
| (&ty::TyFnDef(..), SizeSkeleton::Known(size_to)) |
| if size_to == Pointer.size(&self.infcx.tcx.data_layout) => { |
| // FIXME #19925 Remove this warning after a release cycle. |
| let msg = format!("`{}` is now zero-sized and has to be cast \ |
| to a pointer before transmuting to `{}`", |
| from, to); |
| self.infcx.tcx.sess.add_lint( |
| ::lint::builtin::TRANSMUTE_FROM_FN_ITEM_TYPES, id, span, msg); |
| return; |
| } |
| _ => {} |
| } |
| } |
| |
| // Try to display a sensible error with as much information as possible. |
| let skeleton_string = |ty: Ty<'gcx>, sk| { |
| match sk { |
| Ok(SizeSkeleton::Known(size)) => { |
| format!("{} bits", size.bits()) |
| } |
| Ok(SizeSkeleton::Pointer { tail, .. }) => { |
| format!("pointer to {}", tail) |
| } |
| Err(LayoutError::Unknown(bad)) => { |
| if bad == ty { |
| format!("size can vary") |
| } else { |
| format!("size can vary because of {}", bad) |
| } |
| } |
| Err(err) => err.to_string() |
| } |
| }; |
| |
| span_err!(self.infcx.tcx.sess, span, E0512, |
| "transmute called with differently sized types: \ |
| {} ({}) to {} ({})", |
| from, skeleton_string(from, sk_from), |
| to, skeleton_string(to, sk_to)); |
| } |
| } |
| |
| impl<'a, 'tcx, 'v> Visitor<'v> for ItemVisitor<'a, 'tcx> { |
| // const, static and N in [T; N]. |
| fn visit_expr(&mut self, expr: &hir::Expr) { |
| self.tcx.infer_ctxt(None, None, ProjectionMode::Any).enter(|infcx| { |
| let mut visitor = ExprVisitor { |
| infcx: &infcx |
| }; |
| visitor.visit_expr(expr); |
| }); |
| } |
| |
| fn visit_trait_item(&mut self, item: &hir::TraitItem) { |
| if let hir::ConstTraitItem(_, Some(ref expr)) = item.node { |
| self.visit_const(item.id, expr); |
| } else { |
| intravisit::walk_trait_item(self, item); |
| } |
| } |
| |
| fn visit_impl_item(&mut self, item: &hir::ImplItem) { |
| if let hir::ImplItemKind::Const(_, ref expr) = item.node { |
| self.visit_const(item.id, expr); |
| } else { |
| intravisit::walk_impl_item(self, item); |
| } |
| } |
| |
| fn visit_fn(&mut self, fk: FnKind<'v>, fd: &'v hir::FnDecl, |
| b: &'v hir::Block, s: Span, id: ast::NodeId) { |
| if let FnKind::Closure(..) = fk { |
| span_bug!(s, "intrinsicck: closure outside of function") |
| } |
| let param_env = ty::ParameterEnvironment::for_item(self.tcx, id); |
| self.tcx.infer_ctxt(None, Some(param_env), ProjectionMode::Any).enter(|infcx| { |
| let mut visitor = ExprVisitor { |
| infcx: &infcx |
| }; |
| visitor.visit_fn(fk, fd, b, s, id); |
| }); |
| } |
| } |
| |
| impl<'a, 'gcx, 'tcx, 'v> Visitor<'v> for ExprVisitor<'a, 'gcx, 'tcx> { |
| fn visit_expr(&mut self, expr: &hir::Expr) { |
| if let hir::ExprPath(..) = expr.node { |
| match self.infcx.tcx.expect_def(expr.id) { |
| Def::Fn(did) if self.def_id_is_transmute(did) => { |
| let typ = self.infcx.tcx.node_id_to_type(expr.id); |
| match typ.sty { |
| ty::TyFnDef(_, _, ref bare_fn_ty) if bare_fn_ty.abi == RustIntrinsic => { |
| if let ty::FnConverging(to) = bare_fn_ty.sig.0.output { |
| let from = bare_fn_ty.sig.0.inputs[0]; |
| self.check_transmute(expr.span, from, to, expr.id); |
| } |
| } |
| _ => { |
| span_bug!(expr.span, "transmute wasn't a bare fn?!"); |
| } |
| } |
| } |
| _ => {} |
| } |
| } |
| |
| intravisit::walk_expr(self, expr); |
| } |
| } |