Implement dependency analysis for the precompiled preamble. If any of

the files in the precompiled preamble have changed since it was build,
force the preamble to be rebuilt.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@109937 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 17 insertions, 2 deletions

diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index b6a1ac4492..dc314f1f07 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -110,6 +110,12 @@ namespace SrcMgr {
       Buffer.setPointer(B);
       Buffer.setInt(false);
     }
+    
+    /// \brief Get the underlying buffer, returning NULL if the buffer is not
+    /// yet available.
+    const llvm::MemoryBuffer *getRawBuffer() const {
+      return Buffer.getPointer();
+    }
 
     /// \brief Replace the existing buffer (which will be deleted)
     /// with the given buffer.
diff --git a/include/clang/Frontend/ASTUnit.h b/include/clang/Frontend/ASTUnit.h
index 56e73d9be4..b9db4beafd 100644
--- a/include/clang/Frontend/ASTUnit.h
+++ b/include/clang/Frontend/ASTUnit.h
@@ -21,6 +21,7 @@
 #include "clang/Basic/FileManager.h"
 #include "clang/Index/ASTLocation.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringMap.h"
 #include "llvm/System/Path.h"
 #include "llvm/Support/Timer.h"
 #include <map>
@@ -28,6 +29,7 @@
 #include <vector>
 #include <cassert>
 #include <utility>
+#include <sys/types.h>
 
 namespace llvm {
   class MemoryBuffer;
@@ -135,14 +137,21 @@ private:
   /// \brief The size of the source buffer that we've reserved for the main 
   /// file within the precompiled preamble.
   unsigned PreambleReservedSize;
-  
+
+  /// \brief Keeps track of the files that were used when computing the 
+  /// preamble, with both their buffer size and their modification time.
+  ///
+  /// If any of the files have changed from one compile to the next,
+  /// the preamble must be thrown away.
+  llvm::StringMap<std::pair<off_t, time_t> > FilesInPreamble;
+
   /// \brief When non-NULL, this is the buffer used to store the contents of
   /// the main file when it has been padded for use with the precompiled
   /// preamble.
   llvm::MemoryBuffer *SavedMainFileBuffer;
   
   /// \brief The group of timers associated with this translation unit.
-  llvm::OwningPtr<llvm::TimerGroup> TimerGroup;
+  llvm::OwningPtr<llvm::TimerGroup> TimerGroup;  
   
   /// \brief The timers we've created from the various parses, reparses, etc.
   /// involved in this translation unit.