[decompiler] Several small fixes (#775)

* fix assorted bugs

* stricter return types

* only look for functions in code files

decompiler/util/data_decompile.cpp

@@ -1255,11 +1255,22 @@ std::vector<std::string> decompile_bitfield_enum_from_int(const TypeSpec& type,
               return type_info->entries().at(a) < type_info->entries().at(b);
             });
 
-  for (auto& field_name : bit_sorted_names) {
-    u64 mask = ((u64)1) << type_info->entries().at(field_name);
+  for (auto& kv : type_info->entries()) {
+    u64 mask = ((u64)1) << kv.second;
     if (value & mask) {
       reconstructed |= mask;
-      result.push_back(field_name);
+      result.push_back(kv.first);
+    }
+  }
+
+  int bit_count = 0;
+  {
+    u64 x = value;
+    while (x) {
+      if (x & 1) {
+        bit_count++;
+      }
+      x >>= 1;
     }
   }
 
@@ -1270,10 +1281,18 @@ std::vector<std::string> decompile_bitfield_enum_from_int(const TypeSpec& type,
         type.print(), value, reconstructed));
   }
 
-  // unordered map will give us these fields in a weird order, let's order them explicitly.
-  std::sort(result.begin(), result.end(), [&](const std::string& a, const std::string& b) {
-    return type_info->entries().at(a) < type_info->entries().at(b);
-  });
+  if (bit_count == (int)result.size()) {
+    // unordered map will give us these fields in a weird order, let's order them explicitly.
+    // because we have exactly one name per bit, we can just order them in bit order.
+    std::sort(result.begin(), result.end(), [&](const std::string& a, const std::string& b) {
+      return type_info->entries().at(a) < type_info->entries().at(b);
+    });
+  } else {
+    // we have multiple. Just sort alphabetically and complain.
+    lg::warn("Enum type {} has multiple entries with the same value.", type_info->get_name());
+    std::sort(result.begin(), result.end());
+  }
+
   return result;
 }