analyzeme: Don't panic decoding StringId::INVALID

Author: nagisa

analyzeme/src/stringtable.rs

@@ -120,6 +120,8 @@ impl<'st> StringRef<'st> {
                 Some(&addr) => Ok(addr),
                 None => Err(()),
             }
+        } else if self.id == StringId::INVALID {
+            Err(())
         } else {
             Ok(self.id.to_addr())
         }

measureme/src/profiler.rs

@@ -127,8 +127,7 @@ impl<S: SerializationSink> Profiler<S> {
     }
 
     fn nanos_since_start(&self) -> u64 {
-        let duration_since_start = self.start_time.elapsed();
-        duration_since_start.as_secs() * 1_000_000_000 + duration_since_start.subsec_nanos() as u64
+        self.start_time.elapsed().as_nanos() as _
     }
 }