From a332e2b38fb3c374d751edadfc2c21594f2e7611 Mon Sep 17 00:00:00 2001
From: Aaron Hill <aa1ronham@gmail.com>
Date: Mon, 7 Dec 2020 17:05:28 -0500
Subject: [PATCH] Account for gaps in def path table during decoding
When encoding a proc-macro crate, there may be gaps in the table (since
we only encode the crate root and proc-macro items). Account for this by
checking if the entry is present, rather than using `unwrap()`
---
compiler/rustc_metadata/src/rmeta/decoder.rs | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index c571ed7b612..43f7b2a9928 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1553,6 +1553,8 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
return Some(DefId { krate, index: def_index_guess });
}
+ let is_proc_macro = self.is_proc_macro_crate();
+
// Slow path: We need to find out the new `DefIndex` of the provided
// `DefPathHash`, if its still exists. This requires decoding every `DefPathHash`
// stored in this crate.
@@ -1561,9 +1563,12 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
let mut map = FxHashMap::with_capacity_and_hasher(end_id as usize, Default::default());
for i in 0..end_id {
let def_index = DefIndex::from_u32(i);
- let hash =
- self.root.tables.def_path_hashes.get(self, def_index).unwrap().decode(self);
- map.insert(hash, def_index);
+ // There may be gaps in the encoded table if we're decoding a proc-macro crate
+ if let Some(hash) = self.root.tables.def_path_hashes.get(self, def_index) {
+ map.insert(hash.decode(self), def_index);
+ } else if !is_proc_macro {
+ panic!("Missing def_path_hashes entry for {:?}", def_index);
+ }
}
map
});