flux_metadata/
encoder.rs

1use std::collections::hash_map::Entry;
2
3use flux_middle::global_env::GlobalEnv;
4use rustc_data_structures::fx::FxHashMap;
5use rustc_hir::def_id::{DefId, LOCAL_CRATE};
6use rustc_metadata::errors::FailCreateFileEncoder;
7use rustc_middle::{
8    bug,
9    ty::{self, TyCtxt, codec::TyEncoder},
10};
11use rustc_serialize::{Encodable, Encoder, opaque};
12use rustc_session::config::CrateType;
13use rustc_span::{
14    ExpnId, FileName, SourceFile, Span, SpanEncoder, StableSourceFileId, Symbol, SyntaxContext,
15    def_id::{CrateNum, DefIndex},
16    hygiene::{ExpnIndex, HygieneEncodeContext},
17};
18
19use crate::{CrateMetadata, METADATA_HEADER, SYMBOL_OFFSET, SYMBOL_PREINTERNED, SYMBOL_STR};
20
21struct EncodeContext<'a, 'tcx> {
22    tcx: TyCtxt<'tcx>,
23    opaque: opaque::FileEncoder,
24    type_shorthands: FxHashMap<ty::Ty<'tcx>, usize>,
25    predicate_shorthands: FxHashMap<ty::PredicateKind<'tcx>, usize>,
26    is_proc_macro: bool,
27    hygiene_ctxt: &'a HygieneEncodeContext,
28    symbol_table: FxHashMap<Symbol, usize>, // interpret_allocs: FxIndexSet<interpret::AllocId>,
29}
30
31pub fn encode_metadata(genv: GlobalEnv, path: &std::path::Path) {
32    let mut encoder = opaque::FileEncoder::new(path).unwrap_or_else(|err| {
33        genv.tcx()
34            .sess
35            .dcx()
36            .emit_fatal(FailCreateFileEncoder { err })
37    });
38
39    encoder.emit_raw_bytes(METADATA_HEADER);
40
41    let crate_root = CrateMetadata::new(genv);
42
43    let hygiene_ctxt = HygieneEncodeContext::default();
44    let mut ecx = EncodeContext {
45        tcx: genv.tcx(),
46        opaque: encoder,
47        type_shorthands: Default::default(),
48        predicate_shorthands: Default::default(),
49        is_proc_macro: genv.tcx().crate_types().contains(&CrateType::ProcMacro),
50        hygiene_ctxt: &hygiene_ctxt,
51        symbol_table: Default::default(),
52    };
53
54    crate_root.encode(&mut ecx);
55
56    ecx.opaque.finish().unwrap();
57}
58
59impl SpanEncoder for EncodeContext<'_, '_> {
60    fn encode_crate_num(&mut self, crate_num: CrateNum) {
61        if crate_num != LOCAL_CRATE && self.is_proc_macro {
62            bug!("Attempted to encode non-local CrateNum {crate_num:?} for proc-macro crate");
63        }
64        self.tcx.stable_crate_id(crate_num).encode(self);
65    }
66
67    fn encode_def_index(&mut self, def_index: DefIndex) {
68        self.emit_u32(def_index.as_u32());
69    }
70
71    fn encode_def_id(&mut self, def_id: DefId) {
72        def_id.krate.encode(self);
73        def_id.index.encode(self);
74    }
75
76    fn encode_syntax_context(&mut self, syntax_context: SyntaxContext) {
77        rustc_span::hygiene::raw_encode_syntax_context(syntax_context, self.hygiene_ctxt, self);
78    }
79
80    fn encode_expn_id(&mut self, expn_id: ExpnId) {
81        if expn_id.krate == LOCAL_CRATE {
82            // We will only write details for local expansions. Non-local expansions will fetch
83            // data from the corresponding crate's metadata.
84            // FIXME(#43047) FIXME(#74731) We may eventually want to avoid relying on external
85            // metadata from proc-macro crates.
86            self.hygiene_ctxt.schedule_expn_data_for_encoding(expn_id);
87        }
88        expn_id.krate.encode(self);
89        expn_id.local_id.encode(self);
90    }
91
92    // Code adapted from prusti
93    fn encode_span(&mut self, span: Span) {
94        let sm = self.tcx.sess.source_map();
95        for bp in [span.lo(), span.hi()] {
96            let sf = sm.lookup_source_file(bp);
97            let ssfi = stable_source_file_id_for_export(self.tcx, &sf);
98            ssfi.encode(self);
99            // Not sure if this is the most stable way to encode a BytePos. If it fails
100            // try finding a function in `SourceMap` or `SourceFile` instead. E.g. the
101            // `bytepos_to_file_charpos` fn which returns `CharPos` (though there is
102            // currently no fn mapping back to `BytePos` for decode)
103            (bp - sf.start_pos).encode(self);
104        }
105    }
106
107    fn encode_symbol(&mut self, symbol: Symbol) {
108        // if symbol preinterned, emit tag and symbol index
109        if symbol.is_predefined() {
110            self.opaque.emit_u8(SYMBOL_PREINTERNED);
111            self.opaque.emit_u32(symbol.as_u32());
112        } else {
113            // otherwise write it as string or as offset to it
114            match self.symbol_table.entry(symbol) {
115                Entry::Vacant(o) => {
116                    self.opaque.emit_u8(SYMBOL_STR);
117                    let pos = self.opaque.position();
118                    o.insert(pos);
119                    self.emit_str(symbol.as_str());
120                }
121                Entry::Occupied(o) => {
122                    let x = *o.get();
123                    self.emit_u8(SYMBOL_OFFSET);
124                    self.emit_usize(x);
125                }
126            }
127        }
128    }
129}
130
131impl<'tcx> TyEncoder<'tcx> for EncodeContext<'_, 'tcx> {
132    const CLEAR_CROSS_CRATE: bool = true;
133
134    fn position(&self) -> usize {
135        self.opaque.position()
136    }
137
138    fn type_shorthands(&mut self) -> &mut FxHashMap<ty::Ty<'tcx>, usize> {
139        &mut self.type_shorthands
140    }
141
142    fn predicate_shorthands(&mut self) -> &mut FxHashMap<ty::PredicateKind<'tcx>, usize> {
143        &mut self.predicate_shorthands
144    }
145
146    fn encode_alloc_id(&mut self, _alloc_id: &rustc_middle::mir::interpret::AllocId) {
147        bug!("Encoding `interpret::AllocId` is not supported");
148        // let (index, _) = self.interpret_allocs.insert_full(*alloc_id);
149        // index.encode(self);
150    }
151}
152
153impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for ExpnIndex {
154    fn encode(&self, s: &mut EncodeContext<'a, 'tcx>) {
155        s.emit_u32(self.as_u32());
156    }
157}
158
159macro_rules! encoder_methods {
160    ($($name:ident($ty:ty);)*) => {
161        $(fn $name(&mut self, value: $ty) {
162            self.opaque.$name(value)
163        })*
164    }
165}
166
167impl Encoder for EncodeContext<'_, '_> {
168    encoder_methods! {
169        emit_usize(usize);
170        emit_u128(u128);
171        emit_u64(u64);
172        emit_u32(u32);
173        emit_u16(u16);
174        emit_u8(u8);
175
176        emit_isize(isize);
177        emit_i128(i128);
178        emit_i64(i64);
179        emit_i32(i32);
180        emit_i16(i16);
181        emit_i8(i8);
182
183        emit_bool(bool);
184        emit_char(char);
185        emit_str(&str);
186        emit_raw_bytes(&[u8]);
187    }
188}
189
190fn stable_source_file_id_for_export(tcx: TyCtxt, sf: &SourceFile) -> StableSourceFileId {
191    let working_directory = &tcx.sess.opts.working_dir;
192    let crate_stable_id = tcx.stable_crate_id(sf.cnum);
193    let mut filename = sf.name.clone();
194    if let FileName::Real(original_file_name) = filename {
195        let adapted_file_name = tcx
196            .sess
197            .source_map()
198            .path_mapping()
199            .to_embeddable_absolute_path(original_file_name.clone(), working_directory);
200
201        filename = FileName::Real(adapted_file_name);
202    }
203    StableSourceFileId::from_filename_for_export(&filename, crate_stable_id)
204}
flux_metadata/encoder.rs

flux_metadata/
encoder.rs
