diff --git a/src/Generator.Tests/ASTTestFixture.cs b/src/Generator.Tests/ASTTestFixture.cs
index 91077f17..64df6bb9 100644
--- a/src/Generator.Tests/ASTTestFixture.cs
+++ b/src/Generator.Tests/ASTTestFixture.cs
@@ -20,6 +20,7 @@ namespace CppSharp.Generator.Tests
             Options.Headers.AddRange(files);
 
             Driver = new Driver(Options, new TextDiagnosticPrinter());
+            Driver.BuildParseOptions();
             if (!Driver.ParseCode())
                 throw new Exception("Error parsing the code");
 
diff --git a/src/Generator/Driver.cs b/src/Generator/Driver.cs
index 7d544b62..584a4018 100644
--- a/src/Generator/Driver.cs
+++ b/src/Generator/Driver.cs
@@ -167,12 +167,6 @@ namespace CppSharp
 
         public bool ParseCode()
         {
-            foreach (var header in Options.Headers)
-            {
-                var source = Project.AddFile(header);
-                source.Options = BuildParseOptions(source);
-            }
-
             var parser = new ClangParser(new Parser.AST.ASTContext());
 
             parser.SourceParsed += OnSourceFileParsed;
@@ -185,6 +179,15 @@ namespace CppSharp
             return true;
         }
 
+        public void BuildParseOptions()
+        {
+            foreach (var header in Options.Headers)
+            {
+                var source = Project.AddFile(header);
+                source.Options = BuildParseOptions(source);
+            }
+        }
+
         public ParserTargetInfo TargetInfo { get; set; }
 
         public bool ParseLibraries()
@@ -389,6 +392,8 @@ namespace CppSharp
             if (!options.Quiet)
                 Log.EmitMessage("Parsing code...");
 
+            driver.BuildParseOptions();
+
             if (!driver.ParseCode())
                 return;