compiler/rustc_middle/src/ich/impls_syntax.rs

   1 //! This module contains `HashStable` implementations for various data types
   2 //! from librustc_ast in no particular order.
   3
   4 use crate::ich::StableHashingContext;
   5
   6 use rustc_ast as ast;
   7 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
   8 use rustc_span::{BytePos, NormalizedPos, SourceFile};
   9
  10 use smallvec::SmallVec;
  11
  12 impl<'ctx> rustc_target::HashStableContext for StableHashingContext<'ctx> {}
  13
  14 impl<'a> HashStable<StableHashingContext<'a>> for [ast::Attribute] {
  15     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
  16         if self.is_empty() {
  17             self.len().hash_stable(hcx, hasher);
  18             return;
  19         }
  20
  21         // Some attributes are always ignored during hashing.
  22         let filtered: SmallVec<[&ast::Attribute; 8]> = self
  23             .iter()
  24             .filter(|attr| {
  25                 !attr.is_doc_comment()
  26                     && !attr.ident().map_or(false, |ident| hcx.is_ignored_attr(ident.name))
  27             })
  28             .collect();
  29
  30         filtered.len().hash_stable(hcx, hasher);
  31         for attr in filtered {
  32             attr.hash_stable(hcx, hasher);
  33         }
  34     }
  35 }
  36
  37 impl<'ctx> rustc_ast::HashStableContext for StableHashingContext<'ctx> {
  38     fn hash_attr(&mut self, attr: &ast::Attribute, hasher: &mut StableHasher) {
  39         // Make sure that these have been filtered out.
  40         debug_assert!(!attr.ident().map_or(false, |ident| self.is_ignored_attr(ident.name)));
  41         debug_assert!(!attr.is_doc_comment());
  42
  43         let ast::Attribute { kind, id: _, style, span } = attr;
  44         if let ast::AttrKind::Normal(item, tokens) = kind {
  45             item.hash_stable(self, hasher);
  46             style.hash_stable(self, hasher);
  47             span.hash_stable(self, hasher);
  48             assert_matches!(
  49                 tokens.as_ref(),
  50                 None,
  51                 "Tokens should have been removed during lowering!"
  52             );
  53         } else {
  54             unreachable!();
  55         }
  56     }
  57 }
  58
  59 impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
  60     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
  61         let SourceFile {
  62             name: _, // We hash the smaller name_hash instead of this
  63             name_hash,
  64             name_was_remapped,
  65             unmapped_path: _,
  66             cnum,
  67             // Do not hash the source as it is not encoded
  68             src: _,
  69             ref src_hash,
  70             external_src: _,
  71             start_pos,
  72             end_pos: _,
  73             ref lines,
  74             ref multibyte_chars,
  75             ref non_narrow_chars,
  76             ref normalized_pos,
  77         } = *self;
  78
  79         (name_hash as u64).hash_stable(hcx, hasher);
  80         name_was_remapped.hash_stable(hcx, hasher);
  81
  82         src_hash.hash_stable(hcx, hasher);
  83
  84         // We only hash the relative position within this source_file
  85         lines.len().hash_stable(hcx, hasher);
  86         for &line in lines.iter() {
  87             stable_byte_pos(line, start_pos).hash_stable(hcx, hasher);
  88         }
  89
  90         // We only hash the relative position within this source_file
  91         multibyte_chars.len().hash_stable(hcx, hasher);
  92         for &char_pos in multibyte_chars.iter() {
  93             stable_multibyte_char(char_pos, start_pos).hash_stable(hcx, hasher);
  94         }
  95
  96         non_narrow_chars.len().hash_stable(hcx, hasher);
  97         for &char_pos in non_narrow_chars.iter() {
  98             stable_non_narrow_char(char_pos, start_pos).hash_stable(hcx, hasher);
  99         }
 100
 101         normalized_pos.len().hash_stable(hcx, hasher);
 102         for &char_pos in normalized_pos.iter() {
 103             stable_normalized_pos(char_pos, start_pos).hash_stable(hcx, hasher);
 104         }
 105
 106         cnum.hash_stable(hcx, hasher);
 107     }
 108 }
 109
 110 fn stable_byte_pos(pos: BytePos, source_file_start: BytePos) -> u32 {
 111     pos.0 - source_file_start.0
 112 }
 113
 114 fn stable_multibyte_char(mbc: rustc_span::MultiByteChar, source_file_start: BytePos) -> (u32, u32) {
 115     let rustc_span::MultiByteChar { pos, bytes } = mbc;
 116
 117     (pos.0 - source_file_start.0, bytes as u32)
 118 }
 119
 120 fn stable_non_narrow_char(
 121     swc: rustc_span::NonNarrowChar,
 122     source_file_start: BytePos,
 123 ) -> (u32, u32) {
 124     let pos = swc.pos();
 125     let width = swc.width();
 126
 127     (pos.0 - source_file_start.0, width as u32)
 128 }
 129
 130 fn stable_normalized_pos(np: NormalizedPos, source_file_start: BytePos) -> (u32, u32) {
 131     let NormalizedPos { pos, diff } = np;
 132
 133     (pos.0 - source_file_start.0, diff)
 134 }
 135
 136 impl<'tcx> HashStable<StableHashingContext<'tcx>> for rustc_feature::Features {
 137     fn hash_stable(&self, hcx: &mut StableHashingContext<'tcx>, hasher: &mut StableHasher) {
 138         // Unfortunately we cannot exhaustively list fields here, since the
 139         // struct is macro generated.
 140         self.declared_lang_features.hash_stable(hcx, hasher);
 141         self.declared_lib_features.hash_stable(hcx, hasher);
 142
 143         self.walk_feature_fields(|feature_name, value| {
 144             feature_name.hash_stable(hcx, hasher);
 145             value.hash_stable(hcx, hasher);
 146         });
 147     }
 148 }