Make the CrateNum part of the ExpnId.

compiler/rustc_metadata/src/rmeta/decoder.rs

@@ -30,9 +30,10 @@ use rustc_middle::ty::codec::TyDecoder;
 use rustc_middle::ty::{self, Ty, TyCtxt, Visibility};
 use rustc_serialize::{opaque, Decodable, Decoder};
 use rustc_session::Session;
+use rustc_span::hygiene::{ExpnIndex, MacroKind};
 use rustc_span::source_map::{respan, Spanned};
 use rustc_span::symbol::{sym, Ident, Symbol};
-use rustc_span::{self, hygiene::MacroKind, BytePos, ExpnId, Pos, Span, SyntaxContext, DUMMY_SP};
+use rustc_span::{self, BytePos, ExpnId, Pos, Span, SyntaxContext, DUMMY_SP};
 
 use proc_macro::bridge::client::ProcMacro;
 use std::io;
@@ -348,6 +349,12 @@ impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for DefIndex {
     }
 }
 
+impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for ExpnIndex {
+    fn decode(d: &mut DecodeContext<'a, 'tcx>) -> Result<ExpnIndex, String> {
+        Ok(ExpnIndex::from_u32(d.read_u32()?))
+    }
+}
+
 impl<'a, 'tcx> Decodable<DecodeContext<'a, 'tcx>> for SyntaxContext {
     fn decode(decoder: &mut DecodeContext<'a, 'tcx>) -> Result<SyntaxContext, String> {
         let cdata = decoder.cdata();

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -18,11 +18,11 @@ use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, Visibility};
 use rustc_session::utils::NativeLibKind;
 use rustc_session::{Session, StableCrateId};
+use rustc_span::hygiene::{ExpnData, ExpnHash, ExpnId};
 use rustc_span::source_map::{Span, Spanned};
 use rustc_span::symbol::Symbol;
 
 use rustc_data_structures::sync::Lrc;
-use rustc_span::ExpnId;
 use smallvec::SmallVec;
 use std::any::Any;
 
@@ -494,6 +494,23 @@ impl CrateStore for CStore {
     fn as_any(&self) -> &dyn Any {
         self
     }
+    fn decode_expn_data(&self, sess: &Session, expn_id: ExpnId) -> (ExpnData, ExpnHash) {
+        let crate_data = self.get_crate_data(expn_id.krate);
+        (
+            crate_data
+                .root
+                .expn_data
+                .get(&crate_data, expn_id.local_id)
+                .unwrap()
+                .decode((&crate_data, sess)),
+            crate_data
+                .root
+                .expn_hashes
+                .get(&crate_data, expn_id.local_id)
+                .unwrap()
+                .decode((&crate_data, sess)),
+        )
+    }
 
     fn crate_name(&self, cnum: CrateNum) -> Symbol {
         self.get_crate_data(cnum).root.name

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -31,7 +31,7 @@ use rustc_session::config::CrateType;
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::{self, ExternalSource, FileName, SourceFile, Span, SyntaxContext};
 use rustc_span::{
-    hygiene::{HygieneEncodeContext, MacroKind},
+    hygiene::{ExpnIndex, HygieneEncodeContext, MacroKind},
     RealFileName,
 };
 use rustc_target::abi::VariantIdx;
@@ -168,6 +168,12 @@ impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for DefIndex {
     }
 }
 
+impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for ExpnIndex {
+    fn encode(&self, s: &mut EncodeContext<'a, 'tcx>) -> opaque::EncodeResult {
+        s.emit_u32(self.as_u32())
+    }
+}
+
 impl<'a, 'tcx> Encodable<EncodeContext<'a, 'tcx>> for SyntaxContext {
     fn encode(&self, s: &mut EncodeContext<'a, 'tcx>) -> opaque::EncodeResult {
         rustc_span::hygiene::raw_encode_syntax_context(*self, &s.hygiene_ctxt, s)
@@ -1588,8 +1594,10 @@ impl EncodeContext<'a, 'tcx> {
                 Ok(())
             },
             |(this, _, expn_data_table, expn_hash_table), index, expn_data, hash| {
-                expn_data_table.set(index, this.lazy(expn_data));
-                expn_hash_table.set(index, this.lazy(hash));
+                if let Some(index) = index.as_local() {
+                    expn_data_table.set(index.as_raw(), this.lazy(expn_data));
+                    expn_hash_table.set(index.as_raw(), this.lazy(hash));
+                }
                 Ok(())
             },
         );

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -19,7 +19,7 @@ use rustc_middle::ty::{self, ReprOptions, Ty};
 use rustc_serialize::opaque::Encoder;
 use rustc_session::config::SymbolManglingVersion;
 use rustc_span::edition::Edition;
-use rustc_span::hygiene::MacroKind;
+use rustc_span::hygiene::{ExpnIndex, MacroKind};
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::{self, ExpnData, ExpnHash, ExpnId, Span};
 use rustc_target::spec::{PanicStrategy, TargetTriple};
@@ -170,8 +170,8 @@ macro_rules! Lazy {
 }
 
 type SyntaxContextTable = Lazy<Table<u32, Lazy<SyntaxContextData>>>;
-type ExpnDataTable = Lazy<Table<u32, Lazy<ExpnData>>>;
-type ExpnHashTable = Lazy<Table<u32, Lazy<ExpnHash>>>;
+type ExpnDataTable = Lazy<Table<ExpnIndex, Lazy<ExpnData>>>;
+type ExpnHashTable = Lazy<Table<ExpnIndex, Lazy<ExpnHash>>>;
 
 #[derive(MetadataEncodable, MetadataDecodable)]
 crate struct ProcMacroData {