Look for HIFFY_FUNCTIONS in both variables and definitions

Author: mkeeter

humility-hiffy/src/lib.rs

@@ -184,8 +184,14 @@ impl<'a> HiffyContext<'a> {
     }
 
     fn definition(hubris: &'a HubrisArchive, name: &str) -> Result<HubrisGoff> {
+        // Depending on compiler version, definitions may be in either
+        // `self.definitions` or `self.variables`, so we'll check in both
+        // places.  Behavior depends on whether the compiler included DWARF /
+        // ELF debug info for the type of an otherwise-unused variable marked as
+        // `#[used]`; this changed in rust-lang/rust#140872
         let goff = hubris
             .lookup_definition(name)
+            .or_else(|_| hubris.lookup_variable(name).map(|v| &v.goff))
             .context("expected hiffy definition not found")?;
 
         Ok(*goff)