Introduce a testbed for merging multiple ASTs into a single AST

context with the AST importer. WIP, still useless but at least it has
a test.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95683 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 51 insertions, 0 deletions

diff --git a/include/clang/Driver/CC1Options.td b/include/clang/Driver/CC1Options.td
index 23275b63ff..f0db6e7caf 100644
--- a/include/clang/Driver/CC1Options.td
+++ b/include/clang/Driver/CC1Options.td
@@ -200,6 +200,9 @@ def verify : Flag<"-verify">,
 // CompilerInvocation out of a driver-derived argument vector.
 def cc1 : Flag<"-cc1">;
 
+def ast_merge : Separate<"-ast-merge">,
+  MetaVarName<"<ast file>">,
+  HelpText<"Merge the given AST file into the translation unit being compiled.">;
 def code_completion_at : Separate<"-code-completion-at">,
   MetaVarName<"<file>:<line>:<column>">,
   HelpText<"Dump code-completion information at a location">;
diff --git a/include/clang/Frontend/FrontendAction.h b/include/clang/Frontend/FrontendAction.h
index 29a9302c5c..7b7db3785c 100644
--- a/include/clang/Frontend/FrontendAction.h
+++ b/include/clang/Frontend/FrontendAction.h
@@ -18,6 +18,7 @@ namespace clang {
 class ASTUnit;
 class ASTConsumer;
 class CompilerInstance;
+class ASTMergeAction;
 
 /// FrontendAction - Abstract base class for actions which can be performed by
 /// the frontend.
@@ -25,6 +26,7 @@ class FrontendAction {
   std::string CurrentFile;
   llvm::OwningPtr<ASTUnit> CurrentASTUnit;
   CompilerInstance *Instance;
+  friend class ASTMergeAction;
 
 protected:
   /// @name Implementation Action Interface
@@ -104,6 +106,10 @@ public:
     return *CurrentASTUnit;
   }
 
+  ASTUnit *takeCurrentASTUnit() {
+    return CurrentASTUnit.take();
+  }
+
   void setCurrentFile(llvm::StringRef Value, ASTUnit *AST = 0);
 
   /// @}
diff --git a/include/clang/Frontend/FrontendActions.h b/include/clang/Frontend/FrontendActions.h
index 1eece64282..cbb3508c8a 100644
--- a/include/clang/Frontend/FrontendActions.h
+++ b/include/clang/Frontend/FrontendActions.h
@@ -11,6 +11,8 @@
 #define LLVM_CLANG_FRONTEND_FRONTENDACTIONS_H
 
 #include "clang/Frontend/FrontendAction.h"
+#include <string>
+#include <vector>
 
 namespace clang {
 class FixItRewriter;
@@ -119,6 +121,43 @@ public:
   virtual bool hasCodeCompletionSupport() const { return true; }
 };
 
+/**
+ * \brief Frontend action adaptor that merges ASTs together.
+ *
+ * This action takes an existing AST file and "merges" it into the AST
+ * context, producing a merged context. This action is an action
+ * adaptor, which forwards most of its calls to another action that
+ * will consume the merged context.
+ */
+class ASTMergeAction : public FrontendAction {
+  /// \brief The action that the merge action adapts.
+  FrontendAction *AdaptedAction;
+  
+  /// \brief The set of AST files to merge.
+  std::vector<std::string> ASTFiles;
+
+protected:
+  virtual ASTConsumer *CreateASTConsumer(CompilerInstance &CI,
+                                         llvm::StringRef InFile);
+
+  virtual bool BeginSourceFileAction(CompilerInstance &CI,
+                                     llvm::StringRef Filename);
+
+  virtual void ExecuteAction();
+  virtual void EndSourceFileAction();
+
+public:
+  ASTMergeAction(FrontendAction *AdaptedAction,
+                 std::string *ASTFiles, unsigned NumASTFiles);
+  virtual ~ASTMergeAction();
+
+  virtual bool usesPreprocessorOnly() const;
+  virtual bool usesCompleteTranslationUnit();
+  virtual bool hasPCHSupport() const;
+  virtual bool hasASTSupport() const;
+  virtual bool hasCodeCompletionSupport() const;
+};
+
 //===----------------------------------------------------------------------===//
 // Code Gen AST Actions
 //===----------------------------------------------------------------------===//
diff --git a/include/clang/Frontend/FrontendOptions.h b/include/clang/Frontend/FrontendOptions.h
index 52f639aeb0..80ba77864a 100644
--- a/include/clang/Frontend/FrontendOptions.h
+++ b/include/clang/Frontend/FrontendOptions.h
@@ -110,6 +110,9 @@ public:
   /// The list of plugins to load.
   std::vector<std::string> Plugins;
 
+  /// \brief The list of AST files to merge.
+  std::vector<std::string> ASTMergeFiles;
+
 public:
   FrontendOptions() {
     DebugCodeCompletionPrinter = 1;