3 files changed, 53 insertions, 3 deletions
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 935c4152437..1aaa536cb34 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -278,7 +278,8 @@ public:
 ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
                                              Diagnostic &Diags,
                                              bool OnlyLocalDecls,
-                                             bool CaptureDiagnostics) {
+                                             bool CaptureDiagnostics,
+                                             bool WantPreprocessingRecord) {
   // Create the compiler instance to use for building the AST.
   CompilerInstance Clang;
   llvm::OwningPtr<ASTUnit> AST;
@@ -328,6 +329,15 @@ ASTUnit *ASTUnit::LoadFromCompilerInvocation(CompilerInvocation *CI,
   // Create the preprocessor.
   Clang.createPreprocessor();
 
+  // If the ASTUnit was requested to store information about preprocessing,
+  // create storage for that information and attach an appropriate callback to 
+  // populate that storage.
+  if (WantPreprocessingRecord) {
+    AST->Preprocessing.reset(new PreprocessingRecord);
+    Clang.getPreprocessor().addPPCallbacks(
+                          new PopulatePreprocessingRecord(*AST->Preprocessing));
+  }
+      
   Act.reset(new TopLevelDeclTrackerAction(*AST));
   if (!Act->BeginSourceFile(Clang, Clang.getFrontendOpts().Inputs[0].second,
                            /*IsAST=*/false))
@@ -367,7 +377,8 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
                                       bool OnlyLocalDecls,
                                       RemappedFile *RemappedFiles,
                                       unsigned NumRemappedFiles,
-                                      bool CaptureDiagnostics) {
+                                      bool CaptureDiagnostics,
+                                      bool WantPreprocessingRecord) {
   llvm::SmallVector<const char *, 16> Args;
   Args.push_back("<clang>"); // FIXME: Remove dummy argument.
   Args.insert(Args.end(), ArgBegin, ArgEnd);
@@ -419,5 +430,6 @@ ASTUnit *ASTUnit::LoadFromCommandLine(const char **ArgBegin,
 
   CI->getFrontendOpts().DisableFree = true;
   return LoadFromCompilerInvocation(CI.take(), Diags, OnlyLocalDecls,
-                                    CaptureDiagnostics);
+                                    CaptureDiagnostics, 
+                                    WantPreprocessingRecord);
 }
diff --git a/clang/lib/Lex/CMakeLists.txt b/clang/lib/Lex/CMakeLists.txt
index 81a1e01f964..632fbc6340c 100644
--- a/clang/lib/Lex/CMakeLists.txt
+++ b/clang/lib/Lex/CMakeLists.txt
@@ -16,6 +16,7 @@ add_clang_library(clangLex
   PPMacroExpansion.cpp
   PTHLexer.cpp
   Pragma.cpp
+  PreprocessingRecord.cpp
   Preprocessor.cpp
   PreprocessorLexer.cpp
   ScratchBuffer.cpp
diff --git a/clang/lib/Lex/PreprocessingRecord.cpp b/clang/lib/Lex/PreprocessingRecord.cpp
new file mode 100644
index 00000000000..fe081b69bbb
--- /dev/null
+++ b/clang/lib/Lex/PreprocessingRecord.cpp
@@ -0,0 +1,37 @@
+//===--- PreprocessingRecord.cpp - Record of Preprocessing ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file implements the PreprocessingRecord class, which maintains a record
+//  of what occurred during preprocessing, and its helpers.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/Lex/PreprocessingRecord.h"
+#include "clang/Lex/MacroInfo.h"
+#include "clang/Lex/Token.h"
+
+using namespace clang;
+
+void PreprocessingRecord::addPreprocessedEntity(PreprocessedEntity *Entity) {
+  PreprocessedEntities.push_back(Entity);
+}
+
+void PopulatePreprocessingRecord::MacroExpands(const Token &Id, 
+                                               const MacroInfo* MI) {
+  Record.addPreprocessedEntity(
+                        new (Record) MacroInstantiation(Id.getIdentifierInfo(),
+                                                       Id.getLocation(),
+                                                      MI->getDefinitionLoc()));
+}
+
+void PopulatePreprocessingRecord::MacroDefined(const IdentifierInfo *II, 
+                                               const MacroInfo *MI) {
+  SourceRange R(MI->getDefinitionLoc(), MI->getDefinitionEndLoc());
+  Record.addPreprocessedEntity(
+                  new (Record) MacroDefinition(II, MI->getDefinitionLoc(), R));
+}