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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::codemap::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);
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) => {
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;
}
_ => {}
}
}
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> {
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.resolve_expr(expr) {
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);
}
}