From 8f8d581f76da8a6bf9de45746f908b970f09ee1b Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Sat, 17 Sep 2011 05:35:18 +0000
Subject: [PATCH] When we load header file information from the external source
 (i.e., the AST reader), merge that header file information with whatever
 header file information we already have. Otherwise, we might forget something
 we already knew (e.g., that the header was #import'd already).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139979 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Lex/HeaderSearch.cpp     | 36 ++++++++++++++++++++++++++++--------
 test/Modules/Inputs/point.h  |  2 ++
 test/Modules/header-import.m |  7 +++++++
 3 files changed, 37 insertions(+), 8 deletions(-)
 create mode 100644 test/Modules/Inputs/point.h
 create mode 100644 test/Modules/header-import.m

diff --git a/lib/Lex/HeaderSearch.cpp b/lib/Lex/HeaderSearch.cpp
index ca641d4c0d..931145a8d6 100644
--- a/lib/Lex/HeaderSearch.cpp
+++ b/lib/Lex/HeaderSearch.cpp
@@ -580,7 +580,31 @@ LookupSubframeworkHeader(StringRef Filename,
 // File Info Management.
 //===----------------------------------------------------------------------===//
 
+/// \brief Merge the header file info provided by \p OtherHFI into the current
+/// header file info (\p HFI)
+static void mergeHeaderFileInfo(HeaderFileInfo &HFI, 
+                                const HeaderFileInfo &OtherHFI) {
+  HFI.isImport |= OtherHFI.isImport;
+  HFI.isPragmaOnce |= OtherHFI.isPragmaOnce;
+  HFI.NumIncludes += OtherHFI.NumIncludes;
+  
+  if (!HFI.ControllingMacro && !HFI.ControllingMacroID) {
+    HFI.ControllingMacro = OtherHFI.ControllingMacro;
+    HFI.ControllingMacroID = OtherHFI.ControllingMacroID;
+  }
+  
+  if (OtherHFI.External) {
+    HFI.DirInfo = OtherHFI.DirInfo;
+    HFI.External = OtherHFI.External;
+    HFI.IndexHeaderMapHeader = OtherHFI.IndexHeaderMapHeader;
+  }
 
+  if (HFI.Framework.empty())
+    HFI.Framework = OtherHFI.Framework;
+  
+  HFI.Resolved = true;
+}
+                                
 /// getFileInfo - Return the HeaderFileInfo structure for the specified
 /// FileEntry.
 HeaderFileInfo &HeaderSearch::getFileInfo(const FileEntry *FE) {
@@ -588,10 +612,8 @@ HeaderFileInfo &HeaderSearch::getFileInfo(const FileEntry *FE) {
     FileInfo.resize(FE->getUID()+1);
   
   HeaderFileInfo &HFI = FileInfo[FE->getUID()];
-  if (ExternalSource && !HFI.Resolved) {
-    HFI = ExternalSource->GetHeaderFileInfo(FE);
-    HFI.Resolved = true;
-  }
+  if (ExternalSource && !HFI.Resolved)
+    mergeHeaderFileInfo(HFI, ExternalSource->GetHeaderFileInfo(FE));
   return HFI;
 }
 
@@ -602,10 +624,8 @@ bool HeaderSearch::isFileMultipleIncludeGuarded(const FileEntry *File) {
 
   // Resolve header file info from the external source, if needed.
   HeaderFileInfo &HFI = FileInfo[File->getUID()];
-  if (ExternalSource && !HFI.Resolved) {
-    HFI = ExternalSource->GetHeaderFileInfo(File);
-    HFI.Resolved = true;
-  }
+  if (ExternalSource && !HFI.Resolved)
+    mergeHeaderFileInfo(HFI, ExternalSource->GetHeaderFileInfo(File));
 
   return HFI.isPragmaOnce || HFI.ControllingMacro || HFI.ControllingMacroID;
 }
diff --git a/test/Modules/Inputs/point.h b/test/Modules/Inputs/point.h
new file mode 100644
index 0000000000..eab23d5867
--- /dev/null
+++ b/test/Modules/Inputs/point.h
@@ -0,0 +1,2 @@
+struct Point { int x, y; };
+
diff --git a/test/Modules/header-import.m b/test/Modules/header-import.m
new file mode 100644
index 0000000000..9996dc75c8
--- /dev/null
+++ b/test/Modules/header-import.m
@@ -0,0 +1,7 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodule-cache-path %t -F %S/Inputs -I %S/Inputs -verify %s
+
+#import "point.h"
+__import_module__ Module;
+#import "point.h"
+
-- 
2.50.1