Deal with various exceptions in AT_NAME

Depending on how a binary is build or post-processes the name attribute
can either be in a supplemental debug file (due to dwz) or be artificial
(due to LTO).

In this cases output warnings, but otherwise process as normal.

Signed-off-by: Sjoerd Simons <sjoerd@collabora.com>

src/main.rs

 // Based on the gimli 0.16.1 dwarfdump.rs example
 use anyhow::{anyhow, Error, Result};
 use fallible_iterator::{convert, FallibleIterator};
-use gimli::{Endianity, Reader};
+use gimli::{AttributeValue, Endianity, Reader};
 use object::Object;
 use serde::ser::SerializeMap;
 use serde::{Serialize, Serializer};
@@ -81,17 +81,29 @@ fn list_entries<R: Reader>(
                 .map::<Result<String>, _>(|s| Ok(s.to_string()?.into_owned()))
                 .transpose()?
                 .ok_or_else(|| anyhow!("Missing DW_AT_comp_dir"))?;
-            let comp_name = entry
+
+            let at_name = entry
                 .attr(gimli::DW_AT_name)?
-                .and_then(|attr| attr.string_value(debug_str))
-                .map::<Result<String>, _>(|s| Ok(s.to_string()?.into_owned()))
-                .transpose()?
                 .ok_or_else(|| anyhow!("Missing DW_AT_name"))?;
 
-            v.push(Unit {
-                comp_dir,
-                comp_name,
-            });
+            if let Some(r) = at_name.string_value(debug_str) {
+                let comp_name = r.to_string()?;
+                if comp_name == "<artificial>" {
+                    eprintln!("Warning: Artificial name in compile unit, probably DWARF debug information has been generated with LTO")
+                } else {
+                    v.push(Unit {
+                        comp_dir,
+                        comp_name: comp_name.into_owned(),
+                    });
+                }
+            } else {
+                match at_name.raw_value() {
+                    AttributeValue::DebugStrRefSup(_) => {
+                        eprintln!("Warning: compilation unit name in supplemental file")
+                    }
+                    _ => eprintln!("Warning: compilation unit has unexpected name type"),
+                }
+            }
         }
     }
     Ok(v)