diff --git a/clang/include/clang/ExtractAPI/FrontendActions.h b/clang/include/clang/ExtractAPI/FrontendActions.h
--- a/clang/include/clang/ExtractAPI/FrontendActions.h
+++ b/clang/include/clang/ExtractAPI/FrontendActions.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_CLANG_EXTRACTAPI_FRONTEND_ACTIONS_H
 #define LLVM_CLANG_EXTRACTAPI_FRONTEND_ACTIONS_H
 
+#include "clang/ExtractAPI/API.h"
 #include "clang/Frontend/FrontendAction.h"
 
 namespace clang {
@@ -25,11 +26,19 @@
                                                  StringRef InFile) override;
 
 private:
+  /// A representation of the APIs this action extracts.
+  std::unique_ptr<extractapi::APISet> API;
+
+  /// A stream to the output file of this action.
+  std::unique_ptr<raw_pwrite_stream> OS;
+
+  /// The product this action is extracting API information for.
+  std::string ProductName;
+
   /// The synthesized input buffer that contains all the provided input header
   /// files.
   std::unique_ptr<llvm::MemoryBuffer> Buffer;
 
-public:
   /// Prepare to execute the action on the given CompilerInstance.
   ///
   /// This is called before executing the action on any inputs. This generates a
@@ -37,8 +46,15 @@
   /// list with it before actually executing the action.
   bool PrepareToExecuteAction(CompilerInstance &CI) override;
 
+  /// Called after executing the action on the synthesized input buffer.
+  ///
+  /// Note: Now that we have gathered all the API definitions to surface we can
+  /// emit them in this callback.
+  void EndSourceFileAction() override;
+
   static std::unique_ptr<llvm::raw_pwrite_stream>
   CreateOutputFile(CompilerInstance &CI, StringRef InFile);
+
   static StringRef getInputBufferName() { return "<extract-api-includes>"; }
 };
 
diff --git a/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp b/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp
--- a/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp
+++ b/clang/lib/ExtractAPI/ExtractAPIConsumer.cpp
@@ -41,9 +41,8 @@
 /// information.
 class ExtractAPIVisitor : public RecursiveASTVisitor<ExtractAPIVisitor> {
 public:
-  explicit ExtractAPIVisitor(ASTContext &Context)
-      : Context(Context),
-        API(Context.getTargetInfo().getTriple(), Context.getLangOpts()) {}
+  ExtractAPIVisitor(ASTContext &Context, APISet &API)
+      : Context(Context), API(API) {}
 
   const APISet &getAPI() const { return API; }
 
@@ -304,42 +303,38 @@
   }
 
   ASTContext &Context;
-  APISet API;
+  APISet &API;
 };
 
 class ExtractAPIConsumer : public ASTConsumer {
 public:
-  ExtractAPIConsumer(ASTContext &Context, StringRef ProductName,
-                     std::unique_ptr<raw_pwrite_stream> OS)
-      : Visitor(Context), ProductName(ProductName), OS(std::move(OS)) {}
+  ExtractAPIConsumer(ASTContext &Context, APISet &API)
+      : Visitor(Context, API) {}
 
   void HandleTranslationUnit(ASTContext &Context) override {
     // Use ExtractAPIVisitor to traverse symbol declarations in the context.
     Visitor.TraverseDecl(Context.getTranslationUnitDecl());
-
-    // Setup a SymbolGraphSerializer to write out collected API information in
-    // the Symbol Graph format.
-    // FIXME: Make the kind of APISerializer configurable.
-    SymbolGraphSerializer SGSerializer(Visitor.getAPI(), ProductName);
-    SGSerializer.serialize(*OS);
   }
 
 private:
   ExtractAPIVisitor Visitor;
-  std::string ProductName;
-  std::unique_ptr<raw_pwrite_stream> OS;
 };
 
 } // namespace
 
 std::unique_ptr<ASTConsumer>
 ExtractAPIAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
-  std::unique_ptr<raw_pwrite_stream> OS = CreateOutputFile(CI, InFile);
+  OS = CreateOutputFile(CI, InFile);
   if (!OS)
     return nullptr;
-  return std::make_unique<ExtractAPIConsumer>(
-      CI.getASTContext(), CI.getInvocation().getFrontendOpts().ProductName,
-      std::move(OS));
+
+  ProductName = CI.getFrontendOpts().ProductName;
+
+  // Now that we have enough information about the language options and the
+  // target triple, let's create the APISet before anyone uses it.
+  API = std::make_unique<APISet>(CI.getTarget().getTriple(), CI.getLangOpts());
+
+  return std::make_unique<ExtractAPIConsumer>(CI.getASTContext(), *API);
 }
 
 bool ExtractAPIAction::PrepareToExecuteAction(CompilerInstance &CI) {
@@ -371,6 +366,18 @@
   return true;
 }
 
+void ExtractAPIAction::EndSourceFileAction() {
+  if (!OS)
+    return;
+
+  // Setup a SymbolGraphSerializer to write out collected API information in
+  // the Symbol Graph format.
+  // FIXME: Make the kind of APISerializer configurable.
+  SymbolGraphSerializer SGSerializer(*API, ProductName);
+  SGSerializer.serialize(*OS);
+  OS->flush();
+}
+
 std::unique_ptr<raw_pwrite_stream>
 ExtractAPIAction::CreateOutputFile(CompilerInstance &CI, StringRef InFile) {
   std::unique_ptr<raw_pwrite_stream> OS =