From 37e59a10a7a537428e5997fd5896f5b89fd34e6b Mon Sep 17 00:00:00 2001
From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Wed, 17 Aug 2011 00:31:18 +0000
Subject: [PATCH] Make SourceManager::isBeforeInTranslationUnit handle macro
 locations correctly.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137793 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/SourceManager.h | 22 ++++++++++++++++++++--
 lib/Basic/SourceManager.cpp         | 10 +++-------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index 1bf3278434..2ea19ebc4d 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -367,7 +367,11 @@ class IsBeforeInTranslationUnitCache {
   /// L/R QueryFID - These are the FID's of the cached query.  If these match up
   /// with a subsequent query, the result can be reused.
   FileID LQueryFID, RQueryFID;
-  
+
+  /// \brief True if LQueryFID was created before RQueryFID. This is used
+  /// to compare macro expansion locations.
+  bool IsLQFIDBeforeRQFID;
+
   /// CommonFID - This is the file found in common between the two #include
   /// traces.  It is the nearest common ancestor of the #include tree.
   FileID CommonFID;
@@ -392,13 +396,27 @@ public:
     // use the #include loc in the common file.
     if (LQueryFID != CommonFID) LOffset = LCommonOffset;
     if (RQueryFID != CommonFID) ROffset = RCommonOffset;
+
+    // It is common for multiple macro expansions to be "included" from the same
+    // location (expansion location), in which case use the order of the FileIDs
+    // to determine which came first.
+    if (LOffset == ROffset && LQueryFID != CommonFID && RQueryFID != CommonFID)
+      return IsLQFIDBeforeRQFID;
+
     return LOffset < ROffset;
   }
   
   // Set up a new query.
-  void setQueryFIDs(FileID LHS, FileID RHS) {
+  void setQueryFIDs(FileID LHS, FileID RHS, bool isLFIDBeforeRFID) {
+    assert(LHS != RHS);
     LQueryFID = LHS;
     RQueryFID = RHS;
+    IsLQFIDBeforeRQFID = isLFIDBeforeRFID;
+  }
+
+  void clear() {
+    LQueryFID = RQueryFID = FileID();
+    IsLQFIDBeforeRQFID = false;
   }
   
   void setCommonLoc(FileID commonFID, unsigned lCommonOffset,
diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 4f2922b645..e3106c4a29 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -1484,11 +1484,6 @@ bool SourceManager::isBeforeInTranslationUnit(SourceLocation LHS,
   if (LHS == RHS)
     return false;
 
-  // If both locations are macro expansions, the order of their offsets reflect
-  // the order that the tokens, pointed to by these locations, were expanded
-  // (during parsing each token that is expanded by a macro, expands the
-  // SLocEntries).
-
   std::pair<FileID, unsigned> LOffs = getDecomposedLoc(LHS);
   std::pair<FileID, unsigned> ROffs = getDecomposedLoc(RHS);
 
@@ -1502,7 +1497,8 @@ bool SourceManager::isBeforeInTranslationUnit(SourceLocation LHS,
     return IsBeforeInTUCache.getCachedResult(LOffs.second, ROffs.second);
 
   // Okay, we missed in the cache, start updating the cache for this query.
-  IsBeforeInTUCache.setQueryFIDs(LOffs.first, ROffs.first);
+  IsBeforeInTUCache.setQueryFIDs(LOffs.first, ROffs.first,
+                          /*isLFIDBeforeRFID=*/LOffs.first.ID < ROffs.first.ID);
 
   // We need to find the common ancestor. The only way of doing this is to
   // build the complete include chain for one and then walking up the chain
@@ -1534,7 +1530,7 @@ bool SourceManager::isBeforeInTranslationUnit(SourceLocation LHS,
   // This can happen if a location is in a built-ins buffer.
   // But see PR5662.
   // Clear the lookup cache, it depends on a common location.
-  IsBeforeInTUCache.setQueryFIDs(FileID(), FileID());
+  IsBeforeInTUCache.clear();
   bool LIsBuiltins = strcmp("<built-in>",
                             getBuffer(LOffs.first)->getBufferIdentifier()) == 0;
   bool RIsBuiltins = strcmp("<built-in>",
-- 
2.40.0