From 224d8a74ae4087519f07479bb23de4a3ae53e24f Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Fri, 6 Jan 2012 17:19:32 +0000
Subject: [PATCH] When inferring a submodule ID during module creation, look up
 the include stack to find the first file that is known to be part of the
 module. This copes with situations where the module map doesn't completely
 specify all of the headers that are involved in the module, which can come up
 when there are very strange #include_next chains (e.g., with weird
 compiler/stdlib headers like stdarg.h or float.h).

llvm-svn: 147662
---
 clang/lib/Lex/ModuleMap.cpp             | 21 ++++++++++++++++-----
 clang/test/Modules/Inputs/def-include.h | 13 +++++++++++++
 clang/test/Modules/Inputs/def.h         |  5 +----
 3 files changed, 30 insertions(+), 9 deletions(-)
 create mode 100644 clang/test/Modules/Inputs/def-include.h

diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 6c13938..55fa508 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -426,12 +426,23 @@ Module *ModuleMap::inferModuleFromLocation(FullSourceLoc Loc) {
   
   const SourceManager &SrcMgr = Loc.getManager();
   FileID ExpansionFileID = ExpansionLoc.getFileID();
-  const FileEntry *ExpansionFile = SrcMgr.getFileEntryForID(ExpansionFileID);
-  if (!ExpansionFile)
-    return 0;
   
-  // Find the module that owns this header.
-  return findModuleForHeader(ExpansionFile);
+  while (const FileEntry *ExpansionFile
+           = SrcMgr.getFileEntryForID(ExpansionFileID)) {
+    // Find the module that owns this header (if any).
+    if (Module *Mod = findModuleForHeader(ExpansionFile))
+      return Mod;
+    
+    // No module owns this header, so look up the inclusion chain to see if
+    // any included header has an associated module.
+    SourceLocation IncludeLoc = SrcMgr.getIncludeLoc(ExpansionFileID);
+    if (IncludeLoc.isInvalid())
+      return 0;
+    
+    ExpansionFileID = SrcMgr.getFileID(IncludeLoc);
+  }
+  
+  return 0;
 }
 
 //----------------------------------------------------------------------------//
diff --git a/clang/test/Modules/Inputs/def-include.h b/clang/test/Modules/Inputs/def-include.h
new file mode 100644
index 0000000..9e0e575
--- /dev/null
+++ b/clang/test/Modules/Inputs/def-include.h
@@ -0,0 +1,13 @@
+
+
+
+
+
+
+
+
+
+
+struct B {
+  int b1;
+};
diff --git a/clang/test/Modules/Inputs/def.h b/clang/test/Modules/Inputs/def.h
index 7c1a99e..6d06b08 100644
--- a/clang/test/Modules/Inputs/def.h
+++ b/clang/test/Modules/Inputs/def.h
@@ -1,4 +1,4 @@
-
+#include "def-include.h"
 
 
 
@@ -8,7 +8,4 @@
 }
 @end
 
-struct B {
-  int b1;
-};
 
-- 
2.7.4