diff --git a/src/main/java/com/android/tools/r8/naming/DictionaryReader.java b/src/main/java/com/android/tools/r8/naming/DictionaryReader.java
index 8729dcb..50ff3a1 100644
--- a/src/main/java/com/android/tools/r8/naming/DictionaryReader.java
+++ b/src/main/java/com/android/tools/r8/naming/DictionaryReader.java
@@ -3,7 +3,10 @@
 // BSD-style license that can be found in the LICENSE file.
 package com.android.tools.r8.naming;
 
+import static com.android.tools.r8.position.TextPosition.UNKNOWN_COLUMN;
+
 import com.android.tools.r8.origin.PathOrigin;
+import com.android.tools.r8.position.TextPosition;
 import com.android.tools.r8.utils.ExceptionDiagnostic;
 import com.android.tools.r8.utils.Reporter;
 import com.android.tools.r8.utils.StringDiagnostic;
@@ -19,16 +22,19 @@
 public class DictionaryReader implements AutoCloseable {
 
   private final BufferedReader reader;
+  private final Path path;
 
   public DictionaryReader(Path path) throws IOException {
+    this.path = path;
     this.reader = Files.newBufferedReader(path);
   }
 
-  public String readName() throws IOException {
+  public String readName(Reporter reporter) throws IOException {
     assert reader != null;
 
     StringBuilder name = new StringBuilder();
     int readCharAsInt;
+    int lineNumber = 1;
 
     while ((readCharAsInt = reader.read()) != -1) {
       char readChar = (char) readCharAsInt;
@@ -37,13 +43,29 @@
           || (name.length() == 0 && Character.isJavaIdentifierStart(readChar))) {
         name.append(readChar);
       } else {
-        if (readChar == '#') {
-          reader.readLine();
+        boolean isCommentChar = readChar == '#';
+        boolean isValidEndOfLineInput = readChar == '\n' || readChar == '\r';
+        if (isCommentChar || isValidEndOfLineInput) {
+          if (isCommentChar) {
+            reader.readLine();
+          }
+          lineNumber++;
         }
-
-        if (name.length() != 0) {
+        if (isValidEndOfLineInput && name.length() != 0) {
           return name.toString();
         }
+        name = new StringBuilder();
+        // An illegal character was in the input. We discard the entire line instead of returning as
+        // much as possible, to ensure us not throwing an error in the case of duplicates.
+        if (!isValidEndOfLineInput) {
+          reporter.info(
+              new StringDiagnostic(
+                  "Invalid character in dictionary '" + readChar + "'",
+                  new PathOrigin(path),
+                  new TextPosition(0, lineNumber, UNKNOWN_COLUMN)));
+          reader.readLine();
+          lineNumber++;
+        }
       }
     }
 
@@ -62,7 +84,7 @@
       Set<String> seenNames = new HashSet<>();
       Builder<String> namesBuilder = new ImmutableList.Builder<String>();
       try (DictionaryReader reader = new DictionaryReader(path);) {
-        String name = reader.readName();
+        String name = reader.readName(reporter);
         while (!name.isEmpty()) {
           if (!seenNames.add(name)) {
             reporter.error(
@@ -70,7 +92,7 @@
                     "Duplicate entry for '" + name + "' in dictionary", new PathOrigin(path)));
           }
           namesBuilder.add(name);
-          name = reader.readName();
+          name = reader.readName(reporter);
         }
       } catch (IOException e) {
         reporter.error(new ExceptionDiagnostic(e, new PathOrigin(path)));