src/librustc_passes/layout_test.rs

   1 use rustc::ty::layout::HasDataLayout;
   2 use rustc::ty::layout::HasParamEnv;
   3 use rustc::ty::layout::HasTyCtxt;
   4 use rustc::ty::layout::LayoutOf;
   5 use rustc::ty::layout::TargetDataLayout;
   6 use rustc::ty::layout::TyLayout;
   7 use rustc::ty::ParamEnv;
   8 use rustc::ty::Ty;
   9 use rustc::ty::TyCtxt;
  10 use rustc_ast::ast::Attribute;
  11 use rustc_hir as hir;
  12 use rustc_hir::def_id::DefId;
  13 use rustc_hir::itemlikevisit::ItemLikeVisitor;
  14 use rustc_hir::ItemKind;
  15 use rustc_span::symbol::sym;
  16
  17 pub fn test_layout(tcx: TyCtxt<'_>) {
  18     if tcx.features().rustc_attrs {
  19         // if the `rustc_attrs` feature is not enabled, don't bother testing layout
  20         tcx.hir().krate().visit_all_item_likes(&mut VarianceTest { tcx });
  21     }
  22 }
  23
  24 struct VarianceTest<'tcx> {
  25     tcx: TyCtxt<'tcx>,
  26 }
  27
  28 impl ItemLikeVisitor<'tcx> for VarianceTest<'tcx> {
  29     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
  30         let item_def_id = self.tcx.hir().local_def_id(item.hir_id);
  31
  32         if let ItemKind::TyAlias(..) = item.kind {
  33             for attr in self.tcx.get_attrs(item_def_id).iter() {
  34                 if attr.check_name(sym::rustc_layout) {
  35                     self.dump_layout_of(item_def_id, item, attr);
  36                 }
  37             }
  38         }
  39     }
  40
  41     fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem<'tcx>) {}
  42     fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem<'tcx>) {}
  43 }
  44
  45 impl VarianceTest<'tcx> {
  46     fn dump_layout_of(&self, item_def_id: DefId, item: &hir::Item<'tcx>, attr: &Attribute) {
  47         let tcx = self.tcx;
  48         let param_env = self.tcx.param_env(item_def_id);
  49         let ty = self.tcx.type_of(item_def_id);
  50         match self.tcx.layout_of(param_env.and(ty)) {
  51             Ok(ty_layout) => {
  52                 // Check out the `#[rustc_layout(..)]` attribute to tell what to dump.
  53                 // The `..` are the names of fields to dump.
  54                 let meta_items = attr.meta_item_list().unwrap_or_default();
  55                 for meta_item in meta_items {
  56                     match meta_item.name_or_empty() {
  57                         sym::abi => {
  58                             self.tcx.sess.span_err(item.span, &format!("abi: {:?}", ty_layout.abi));
  59                         }
  60
  61                         sym::align => {
  62                             self.tcx
  63                                 .sess
  64                                 .span_err(item.span, &format!("align: {:?}", ty_layout.align));
  65                         }
  66
  67                         sym::size => {
  68                             self.tcx
  69                                 .sess
  70                                 .span_err(item.span, &format!("size: {:?}", ty_layout.size));
  71                         }
  72
  73                         sym::homogeneous_aggregate => {
  74                             self.tcx.sess.span_err(
  75                                 item.span,
  76                                 &format!(
  77                                     "homogeneous_aggregate: {:?}",
  78                                     ty_layout
  79                                         .homogeneous_aggregate(&UnwrapLayoutCx { tcx, param_env }),
  80                                 ),
  81                             );
  82                         }
  83
  84                         name => {
  85                             self.tcx.sess.span_err(
  86                                 meta_item.span(),
  87                                 &format!("unrecognized field name `{}`", name),
  88                             );
  89                         }
  90                     }
  91                 }
  92             }
  93
  94             Err(layout_error) => {
  95                 self.tcx.sess.span_err(item.span, &format!("layout error: {:?}", layout_error));
  96             }
  97         }
  98     }
  99 }
 100
 101 struct UnwrapLayoutCx<'tcx> {
 102     tcx: TyCtxt<'tcx>,
 103     param_env: ParamEnv<'tcx>,
 104 }
 105
 106 impl LayoutOf for UnwrapLayoutCx<'tcx> {
 107     type Ty = Ty<'tcx>;
 108     type TyLayout = TyLayout<'tcx>;
 109
 110     fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
 111         self.tcx.layout_of(self.param_env.and(ty)).unwrap()
 112     }
 113 }
 114
 115 impl HasTyCtxt<'tcx> for UnwrapLayoutCx<'tcx> {
 116     fn tcx(&self) -> TyCtxt<'tcx> {
 117         self.tcx
 118     }
 119 }
 120
 121 impl HasParamEnv<'tcx> for UnwrapLayoutCx<'tcx> {
 122     fn param_env(&self) -> ParamEnv<'tcx> {
 123         self.param_env
 124     }
 125 }
 126
 127 impl HasDataLayout for UnwrapLayoutCx<'tcx> {
 128     fn data_layout(&self) -> &TargetDataLayout {
 129         self.tcx.data_layout()
 130     }
 131 }