compiler/rustc_passes/src/layout_test.rs

   1 use rustc_ast::Attribute;
   2 use rustc_hir as hir;
   3 use rustc_hir::def_id::LocalDefId;
   4 use rustc_hir::itemlikevisit::ItemLikeVisitor;
   5 use rustc_hir::ItemKind;
   6 use rustc_middle::ty::layout::{HasParamEnv, HasTyCtxt, TyAndLayout};
   7 use rustc_middle::ty::{ParamEnv, Ty, TyCtxt};
   8 use rustc_span::symbol::sym;
   9 use rustc_target::abi::{HasDataLayout, LayoutOf, TargetDataLayout};
  10
  11 pub fn test_layout(tcx: TyCtxt<'_>) {
  12     if tcx.features().rustc_attrs {
  13         // if the `rustc_attrs` feature is not enabled, don't bother testing layout
  14         tcx.hir().krate().visit_all_item_likes(&mut LayoutTest { tcx });
  15     }
  16 }
  17
  18 struct LayoutTest<'tcx> {
  19     tcx: TyCtxt<'tcx>,
  20 }
  21
  22 impl ItemLikeVisitor<'tcx> for LayoutTest<'tcx> {
  23     fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
  24         match item.kind {
  25             ItemKind::TyAlias(..)
  26             | ItemKind::Enum(..)
  27             | ItemKind::Struct(..)
  28             | ItemKind::Union(..) => {
  29                 for attr in self.tcx.get_attrs(item.def_id.to_def_id()).iter() {
  30                     if self.tcx.sess.check_name(attr, sym::rustc_layout) {
  31                         self.dump_layout_of(item.def_id, item, attr);
  32                     }
  33                 }
  34             }
  35             _ => {}
  36         }
  37     }
  38
  39     fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem<'tcx>) {}
  40     fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem<'tcx>) {}
  41     fn visit_foreign_item(&mut self, _: &'tcx hir::ForeignItem<'tcx>) {}
  42 }
  43
  44 impl LayoutTest<'tcx> {
  45     fn dump_layout_of(&self, item_def_id: LocalDefId, item: &hir::Item<'tcx>, attr: &Attribute) {
  46         let tcx = self.tcx;
  47         let param_env = self.tcx.param_env(item_def_id);
  48         let ty = self.tcx.type_of(item_def_id);
  49         match self.tcx.layout_of(param_env.and(ty)) {
  50             Ok(ty_layout) => {
  51                 // Check out the `#[rustc_layout(..)]` attribute to tell what to dump.
  52                 // The `..` are the names of fields to dump.
  53                 let meta_items = attr.meta_item_list().unwrap_or_default();
  54                 for meta_item in meta_items {
  55                     match meta_item.name_or_empty() {
  56                         sym::abi => {
  57                             self.tcx.sess.span_err(item.span, &format!("abi: {:?}", ty_layout.abi));
  58                         }
  59
  60                         sym::align => {
  61                             self.tcx
  62                                 .sess
  63                                 .span_err(item.span, &format!("align: {:?}", ty_layout.align));
  64                         }
  65
  66                         sym::size => {
  67                             self.tcx
  68                                 .sess
  69                                 .span_err(item.span, &format!("size: {:?}", ty_layout.size));
  70                         }
  71
  72                         sym::homogeneous_aggregate => {
  73                             self.tcx.sess.span_err(
  74                                 item.span,
  75                                 &format!(
  76                                     "homogeneous_aggregate: {:?}",
  77                                     ty_layout
  78                                         .homogeneous_aggregate(&UnwrapLayoutCx { tcx, param_env }),
  79                                 ),
  80                             );
  81                         }
  82
  83                         sym::debug => {
  84                             let normalized_ty = self.tcx.normalize_erasing_regions(
  85                                 param_env.with_reveal_all_normalized(self.tcx),
  86                                 ty,
  87                             );
  88                             self.tcx.sess.span_err(
  89                                 item.span,
  90                                 &format!("layout_of({:?}) = {:#?}", normalized_ty, *ty_layout),
  91                             );
  92                         }
  93
  94                         name => {
  95                             self.tcx.sess.span_err(
  96                                 meta_item.span(),
  97                                 &format!("unrecognized field name `{}`", name),
  98                             );
  99                         }
 100                     }
 101                 }
 102             }
 103
 104             Err(layout_error) => {
 105                 self.tcx.sess.span_err(item.span, &format!("layout error: {:?}", layout_error));
 106             }
 107         }
 108     }
 109 }
 110
 111 struct UnwrapLayoutCx<'tcx> {
 112     tcx: TyCtxt<'tcx>,
 113     param_env: ParamEnv<'tcx>,
 114 }
 115
 116 impl LayoutOf for UnwrapLayoutCx<'tcx> {
 117     type Ty = Ty<'tcx>;
 118     type TyAndLayout = TyAndLayout<'tcx>;
 119
 120     fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyAndLayout {
 121         self.tcx.layout_of(self.param_env.and(ty)).unwrap()
 122     }
 123 }
 124
 125 impl HasTyCtxt<'tcx> for UnwrapLayoutCx<'tcx> {
 126     fn tcx(&self) -> TyCtxt<'tcx> {
 127         self.tcx
 128     }
 129 }
 130
 131 impl HasParamEnv<'tcx> for UnwrapLayoutCx<'tcx> {
 132     fn param_env(&self) -> ParamEnv<'tcx> {
 133         self.param_env
 134     }
 135 }
 136
 137 impl HasDataLayout for UnwrapLayoutCx<'tcx> {
 138     fn data_layout(&self) -> &TargetDataLayout {
 139         self.tcx.data_layout()
 140     }
 141 }