src/librustc_passes/layout_test.rs

   1 use rustc_ast::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         let item_def_id = self.tcx.hir().local_def_id(item.hir_id);
  25
  26         match item.kind {
  27             ItemKind::TyAlias(..)
  28             | ItemKind::Enum(..)
  29             | ItemKind::Struct(..)
  30             | ItemKind::Union(..)
  31             | ItemKind::OpaqueTy(..) => {
  32                 for attr in self.tcx.get_attrs(item_def_id.to_def_id()).iter() {
  33                     if attr.check_name(sym::rustc_layout) {
  34                         self.dump_layout_of(item_def_id, item, attr);
  35                     }
  36                 }
  37             }
  38             _ => {}
  39         }
  40     }
  41
  42     fn visit_trait_item(&mut self, _: &'tcx hir::TraitItem<'tcx>) {}
  43     fn visit_impl_item(&mut self, _: &'tcx hir::ImplItem<'tcx>) {}
  44 }
  45
  46 impl LayoutTest<'tcx> {
  47     fn dump_layout_of(&self, item_def_id: LocalDefId, item: &hir::Item<'tcx>, attr: &Attribute) {
  48         let tcx = self.tcx;
  49         let param_env = self.tcx.param_env(item_def_id);
  50         let ty = self.tcx.type_of(item_def_id);
  51         match self.tcx.layout_of(param_env.and(ty)) {
  52             Ok(ty_layout) => {
  53                 // Check out the `#[rustc_layout(..)]` attribute to tell what to dump.
  54                 // The `..` are the names of fields to dump.
  55                 let meta_items = attr.meta_item_list().unwrap_or_default();
  56                 for meta_item in meta_items {
  57                     match meta_item.name_or_empty() {
  58                         sym::abi => {
  59                             self.tcx.sess.span_err(item.span, &format!("abi: {:?}", ty_layout.abi));
  60                         }
  61
  62                         sym::align => {
  63                             self.tcx
  64                                 .sess
  65                                 .span_err(item.span, &format!("align: {:?}", ty_layout.align));
  66                         }
  67
  68                         sym::size => {
  69                             self.tcx
  70                                 .sess
  71                                 .span_err(item.span, &format!("size: {:?}", ty_layout.size));
  72                         }
  73
  74                         sym::homogeneous_aggregate => {
  75                             self.tcx.sess.span_err(
  76                                 item.span,
  77                                 &format!(
  78                                     "homogeneous_aggregate: {:?}",
  79                                     ty_layout
  80                                         .homogeneous_aggregate(&UnwrapLayoutCx { tcx, param_env }),
  81                                 ),
  82                             );
  83                         }
  84
  85                         sym::debug => {
  86                             self.tcx.sess.span_err(
  87                                 item.span,
  88                                 &format!("layout_of({:?}) = {:#?}", ty, *ty_layout),
  89                             );
  90                         }
  91
  92                         name => {
  93                             self.tcx.sess.span_err(
  94                                 meta_item.span(),
  95                                 &format!("unrecognized field name `{}`", name),
  96                             );
  97                         }
  98                     }
  99                 }
 100             }
 101
 102             Err(layout_error) => {
 103                 self.tcx.sess.span_err(item.span, &format!("layout error: {:?}", layout_error));
 104             }
 105         }
 106     }
 107 }
 108
 109 struct UnwrapLayoutCx<'tcx> {
 110     tcx: TyCtxt<'tcx>,
 111     param_env: ParamEnv<'tcx>,
 112 }
 113
 114 impl LayoutOf for UnwrapLayoutCx<'tcx> {
 115     type Ty = Ty<'tcx>;
 116     type TyAndLayout = TyAndLayout<'tcx>;
 117
 118     fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyAndLayout {
 119         self.tcx.layout_of(self.param_env.and(ty)).unwrap()
 120     }
 121 }
 122
 123 impl HasTyCtxt<'tcx> for UnwrapLayoutCx<'tcx> {
 124     fn tcx(&self) -> TyCtxt<'tcx> {
 125         self.tcx
 126     }
 127 }
 128
 129 impl HasParamEnv<'tcx> for UnwrapLayoutCx<'tcx> {
 130     fn param_env(&self) -> ParamEnv<'tcx> {
 131         self.param_env
 132     }
 133 }
 134
 135 impl HasDataLayout for UnwrapLayoutCx<'tcx> {
 136     fn data_layout(&self) -> &TargetDataLayout {
 137         self.tcx.data_layout()
 138     }
 139 }