1 files changed, 15 insertions, 10 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index ddbb4d4b429..79677de936b 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -341,9 +341,10 @@ Optional<FileEntryRef> DirectoryLookup::LookupFile(
     SmallVectorImpl<char> *SearchPath, SmallVectorImpl<char> *RelativePath,
     Module *RequestingModule, ModuleMap::KnownHeader *SuggestedModule,
     bool &InUserSpecifiedSystemFramework, bool &IsFrameworkFound,
-    bool &HasBeenMapped, SmallVectorImpl<char> &MappedName) const {
+    bool &IsInHeaderMap, SmallVectorImpl<char> &MappedName) const {
   InUserSpecifiedSystemFramework = false;
-  HasBeenMapped = false;
+  IsInHeaderMap = false;
+  MappedName.clear();
 
   SmallString<1024> TmpDir;
   if (isNormalDir()) {
@@ -377,6 +378,8 @@ Optional<FileEntryRef> DirectoryLookup::LookupFile(
   if (Dest.empty())
     return None;
 
+  IsInHeaderMap = true;
+
   auto FixupSearchPath = [&]() {
     if (SearchPath) {
       StringRef SearchPathRef(getName());
@@ -393,10 +396,8 @@ Optional<FileEntryRef> DirectoryLookup::LookupFile(
   // ("Foo.h" -> "Foo/Foo.h"), in which case continue header lookup using the
   // framework include.
   if (llvm::sys::path::is_relative(Dest)) {
-    MappedName.clear();
     MappedName.append(Dest.begin(), Dest.end());
     Filename = StringRef(MappedName.begin(), MappedName.size());
-    HasBeenMapped = true;
     Optional<FileEntryRef> Result = HM->LookupFile(Filename, HS.getFileMgr());
     if (Result) {
       FixupSearchPath();
@@ -883,18 +884,22 @@ Optional<FileEntryRef> HeaderSearch::LookupFile(
   // Check each directory in sequence to see if it contains this file.
   for (; i != SearchDirs.size(); ++i) {
     bool InUserSpecifiedSystemFramework = false;
-    bool HasBeenMapped = false;
+    bool IsInHeaderMap = false;
     bool IsFrameworkFoundInDir = false;
     Optional<FileEntryRef> File = SearchDirs[i].LookupFile(
         Filename, *this, IncludeLoc, SearchPath, RelativePath, RequestingModule,
         SuggestedModule, InUserSpecifiedSystemFramework, IsFrameworkFoundInDir,
-        HasBeenMapped, MappedName);
-    if (HasBeenMapped) {
+        IsInHeaderMap, MappedName);
+    if (!MappedName.empty()) {
+      assert(IsInHeaderMap && "MappedName should come from a header map");
       CacheLookup.MappedName =
-          copyString(Filename, LookupFileCache.getAllocator());
-      if (IsMapped)
-        *IsMapped = true;
+          copyString(MappedName, LookupFileCache.getAllocator());
     }
+    if (IsMapped)
+      // A filename is mapped when a header map remapped it to a relative path
+      // used in subsequent header search or to an absolute path pointing to an
+      // existing file.
+      *IsMapped |= (!MappedName.empty() || (IsInHeaderMap && File));
     if (IsFrameworkFound)
       // Because we keep a filename remapped for subsequent search directory
       // lookups, ignore IsFrameworkFoundInDir after the first remapping and not