From 04cb14791e064bcf5c322123297f232bf8c4cc21 Mon Sep 17 00:00:00 2001
From: Christian Blichmann <cblichmann@google.com>
Date: Tue, 13 Jun 2023 01:03:52 -0700
Subject: [PATCH] Clang tool: Enable incremental pre-processing

This avoids doing extra work when processing multiple input files.

PiperOrigin-RevId: 539884025
Change-Id: I8e48495f33c09bc53e70f4d5c1d730fe7c1202b2
---
 sandboxed_api/tools/clang_generator/generator.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/sandboxed_api/tools/clang_generator/generator.h b/sandboxed_api/tools/clang_generator/generator.h
index 218981f..5cd118e 100644
--- a/sandboxed_api/tools/clang_generator/generator.h
+++ b/sandboxed_api/tools/clang_generator/generator.h
@@ -26,6 +26,7 @@
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendAction.h"
+#include "clang/Lex/Preprocessor.h"
 #include "clang/Tooling/Tooling.h"
 #include "sandboxed_api/tools/clang_generator/emitter.h"
 #include "sandboxed_api/tools/clang_generator/types.h"
@@ -116,6 +117,11 @@ class GeneratorAction : public clang::ASTFrontendAction {
                                                   emitter_, options_);
   }
 
+  bool BeginSourceFileAction(clang::CompilerInstance& ci) override {
+    ci.getPreprocessor().enableIncrementalProcessing();
+    return true;
+  }
+
   bool hasCodeCompletionSupport() const override { return false; }
 
   Emitter& emitter_;