diff --git a/sandboxed_api/tools/clang_generator/generator.cc b/sandboxed_api/tools/clang_generator/generator.cc
index 69b5db2..c5661ee 100644
--- a/sandboxed_api/tools/clang_generator/generator.cc
+++ b/sandboxed_api/tools/clang_generator/generator.cc
@@ -21,6 +21,7 @@
 #include "absl/status/statusor.h"
 #include "clang/AST/Type.h"
 #include "clang/Format/Format.h"
+#include "clang/Lex/PreprocessorOptions.h"
 #include "sandboxed_api/tools/clang_generator/diagnostics.h"
 #include "sandboxed_api/tools/clang_generator/emitter.h"
 #include "sandboxed_api/util/fileops.h"
@@ -64,7 +65,6 @@ bool GeneratorASTVisitor::VisitFunctionDecl(clang::FunctionDecl* decl) {
 }
 
 void GeneratorASTConsumer::HandleTranslationUnit(clang::ASTContext& context) {
-  std::cout << "Processing " << in_file_ << "\n";
   if (!visitor_.TraverseDecl(context.getTranslationUnitDecl())) {
     ReportFatalError(context.getDiagnostics(),
                      context.getTranslationUnitDecl()->getBeginLoc(),
@@ -79,4 +79,48 @@ void GeneratorASTConsumer::HandleTranslationUnit(clang::ASTContext& context) {
   }
 }
 
+bool GeneratorFactory::runInvocation(
+    std::shared_ptr<clang::CompilerInvocation> invocation,
+    clang::FileManager* files,
+    std::shared_ptr<clang::PCHContainerOperations> pch_container_ops,
+    clang::DiagnosticConsumer* diag_consumer) {
+  auto& options = invocation->getPreprocessorOpts();
+  // Explicitly ask to define __clang_analyzer__ macro.
+  options.SetUpStaticAnalyzer = true;
+  for (const auto& def : {
+           // Enable code to detect whether it is being SAPI-ized
+           "__SAPI__",
+           // TODO(b/222241644): Figure out how to deal with intrinsics properly
+           "__builtin_ia32_paddsb128=",
+           "__builtin_ia32_paddsb256=",
+           "__builtin_ia32_paddsb512=",
+           "__builtin_ia32_paddsw128=",
+           "__builtin_ia32_paddsw256=",
+           "__builtin_ia32_paddsw512=",
+           "__builtin_ia32_paddusb128=",
+           "__builtin_ia32_paddusb256=",
+           "__builtin_ia32_paddusb512=",
+           "__builtin_ia32_paddusw128=",
+           "__builtin_ia32_paddusw256=",
+           "__builtin_ia32_paddusw512=",
+           "__builtin_ia32_psubsb128=",
+           "__builtin_ia32_psubsb256=",
+           "__builtin_ia32_psubsb512=",
+           "__builtin_ia32_psubsw128=",
+           "__builtin_ia32_psubsw256=",
+           "__builtin_ia32_psubsw512=",
+           "__builtin_ia32_psubusb128=",
+           "__builtin_ia32_psubusb256=",
+           "__builtin_ia32_psubusb512=",
+           "__builtin_ia32_psubusw128=",
+           "__builtin_ia32_psubusw256=",
+           "__builtin_ia32_psubusw512=",
+       }) {
+    options.addMacroDef(def);
+  }
+  return FrontendActionFactory::runInvocation(std::move(invocation), files,
+                                              std::move(pch_container_ops),
+                                              diag_consumer);
+}
+
 }  // namespace sapi
diff --git a/sandboxed_api/tools/clang_generator/generator.h b/sandboxed_api/tools/clang_generator/generator.h
index e83423c..2b211b0 100644
--- a/sandboxed_api/tools/clang_generator/generator.h
+++ b/sandboxed_api/tools/clang_generator/generator.h
@@ -25,6 +25,7 @@
 #include "clang/AST/ASTConsumer.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendAction.h"
 #include "clang/Tooling/Tooling.h"
 #include "sandboxed_api/tools/clang_generator/emitter.h"
@@ -123,6 +124,12 @@ class GeneratorFactory : public clang::tooling::FrontendActionFactory {
   }
 #endif
 
+  bool runInvocation(
+      std::shared_ptr<clang::CompilerInvocation> invocation,
+      clang::FileManager* files,
+      std::shared_ptr<clang::PCHContainerOperations> pch_container_ops,
+      clang::DiagnosticConsumer* diag_consumer) override;
+
   Emitter& emitter_;
   const GeneratorOptions& options_;
 };