1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

use rustc_ast as ast;
use rustc_data_structures::stable_hasher::{HashStable, HashingControls, StableHasher};
use rustc_data_structures::sync::Lrc;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::definitions::DefPathHash;
use rustc_session::cstore::Untracked;
use rustc_session::Session;
use rustc_span::source_map::SourceMap;
use rustc_span::symbol::Symbol;
use rustc_span::{BytePos, CachingSourceMapView, SourceFile, Span, SpanData, DUMMY_SP};

use crate::ich;

/// This is the context state available during incr. comp. hashing. It contains
/// enough information to transform `DefId`s and `HirId`s into stable `DefPath`s (i.e.,
/// a reference to the `TyCtxt`) and it holds a few caches for speeding up various
/// things (e.g., each `DefId`/`DefPath` is only hashed once).
#[derive(Clone)]
pub struct StableHashingContext<'a> {
    untracked: &'a Untracked,
    // The value of `-Z incremental-ignore-spans`.
    // This field should only be used by `unstable_opts_incremental_ignore_span`
    incremental_ignore_spans: bool,
    // Very often, we are hashing something that does not need the
    // `CachingSourceMapView`, so we initialize it lazily.
    raw_source_map: &'a SourceMap,
    caching_source_map: Option<CachingSourceMapView<'a>>,
    hashing_controls: HashingControls,
}

impl<'a> StableHashingContext<'a> {
    #[inline]
    pub fn new(sess: &'a Session, untracked: &'a Untracked) -> Self {
        let hash_spans_initial = !sess.opts.unstable_opts.incremental_ignore_spans;

        StableHashingContext {
            untracked,
            incremental_ignore_spans: sess.opts.unstable_opts.incremental_ignore_spans,
            caching_source_map: None,
            raw_source_map: sess.source_map(),
            hashing_controls: HashingControls { hash_spans: hash_spans_initial },
        }
    }

    #[inline]
    pub fn while_hashing_spans<F: FnOnce(&mut Self)>(&mut self, hash_spans: bool, f: F) {
        let prev_hash_spans = self.hashing_controls.hash_spans;
        self.hashing_controls.hash_spans = hash_spans;
        f(self);
        self.hashing_controls.hash_spans = prev_hash_spans;
    }

    #[inline]
    pub fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
        if let Some(def_id) = def_id.as_local() {
            self.local_def_path_hash(def_id)
        } else {
            self.untracked.cstore.read().def_path_hash(def_id)
        }
    }

    #[inline]
    pub fn local_def_path_hash(&self, def_id: LocalDefId) -> DefPathHash {
        self.untracked.definitions.read().def_path_hash(def_id)
    }

    #[inline]
    pub fn source_map(&mut self) -> &mut CachingSourceMapView<'a> {
        match self.caching_source_map {
            Some(ref mut sm) => sm,
            ref mut none => {
                *none = Some(CachingSourceMapView::new(self.raw_source_map));
                none.as_mut().unwrap()
            }
        }
    }

    #[inline]
    pub fn is_ignored_attr(&self, name: Symbol) -> bool {
        ich::IGNORED_ATTRIBUTES.contains(&name)
    }

    #[inline]
    pub fn hashing_controls(&self) -> HashingControls {
        self.hashing_controls.clone()
    }
}

impl<'a> HashStable<StableHashingContext<'a>> for ast::NodeId {
    #[inline]
    fn hash_stable(&self, _: &mut StableHashingContext<'a>, _: &mut StableHasher) {
        panic!("Node IDs should not appear in incremental state");
    }
}

impl<'a> rustc_span::HashStableContext for StableHashingContext<'a> {
    #[inline]
    fn hash_spans(&self) -> bool {
        self.hashing_controls.hash_spans
    }

    #[inline]
    fn unstable_opts_incremental_ignore_spans(&self) -> bool {
        self.incremental_ignore_spans
    }

    #[inline]
    fn def_path_hash(&self, def_id: DefId) -> DefPathHash {
        self.def_path_hash(def_id)
    }

    #[inline]
    fn def_span(&self, def_id: LocalDefId) -> Span {
        self.untracked.source_span.get(def_id).unwrap_or(DUMMY_SP)
    }

    #[inline]
    fn span_data_to_lines_and_cols(
        &mut self,
        span: &SpanData,
    ) -> Option<(Lrc<SourceFile>, usize, BytePos, usize, BytePos)> {
        self.source_map().span_data_to_lines_and_cols(span)
    }

    #[inline]
    fn hashing_controls(&self) -> HashingControls {
        self.hashing_controls.clone()
    }
}

impl<'a> rustc_session::HashStableContext for StableHashingContext<'a> {}