[PCH/Modules] Re-apply r172620 and r172629, now with 100% less infinite loops!

Makes sure that a deserialized macro is only added to the preprocessor macro definitions only once.
Unfortunately I couldn't get a reduced test case.

rdar://13016031

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172843 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 9 insertions, 2 deletions

diff --git a/include/clang/Lex/MacroInfo.h b/include/clang/Lex/MacroInfo.h
index aeedd735e3..c6b44a9422 100644
--- a/include/clang/Lex/MacroInfo.h
+++ b/include/clang/Lex/MacroInfo.h
@@ -169,6 +169,14 @@ public:
   /// \brief Get previous definition of the macro with the same name.
   MacroInfo *getPreviousDefinition() { return PreviousDefinition; }
 
+  /// \brief Get the first definition in the chain.
+  MacroInfo *getFirstDefinition() {
+    MacroInfo *MI = this;
+    while (MI->PreviousDefinition)
+      MI = MI->PreviousDefinition;
+    return MI;
+  }
+
   /// \brief Find macro definition active in the specified source location. If
   /// this macro was not defined there, return NULL.
   const MacroInfo *findDefinitionAtLoc(SourceLocation L,
diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 24b6a18881..faaec3517d 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -533,8 +533,7 @@ public:
   /// \brief Specify a macro for this identifier.
   void setMacroInfo(IdentifierInfo *II, MacroInfo *MI);
   /// \brief Add a MacroInfo that was loaded from an AST file.
-  void addLoadedMacroInfo(IdentifierInfo *II, MacroInfo *MI,
-                          MacroInfo *Hint = 0);
+  void addLoadedMacroInfo(IdentifierInfo *II, MacroInfo *MI);
   /// \brief Make the given MacroInfo, that was loaded from an AST file and
   /// previously hidden, visible.
   void makeLoadedMacroInfoVisible(IdentifierInfo *II, MacroInfo *MI);