2 files changed, 29 insertions, 12 deletions
diff --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index b40305d0fc2..85263fec626 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -848,13 +848,27 @@ unsigned MCAsmStreamer::EmitDwarfFileDirective(unsigned FileNo,
                                                StringRef Directory,
                                                StringRef Filename,
                                                unsigned CUID) {
+  assert(CUID == 0);
+
+  MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
+  unsigned NumFiles = Table.getMCDwarfFiles().size();
+  FileNo = Table.getFile(Directory, Filename, FileNo);
+  if (FileNo == 0)
+    return 0;
+  if (NumFiles == Table.getMCDwarfFiles().size())
+    return FileNo;
+
+  SmallString<128> FullPathName;
+
   if (!UseDwarfDirectory && !Directory.empty()) {
     if (sys::path::is_absolute(Filename))
-      return EmitDwarfFileDirective(FileNo, "", Filename, CUID);
-
-    SmallString<128> FullPathName = Directory;
-    sys::path::append(FullPathName, Filename);
-    return EmitDwarfFileDirective(FileNo, "", FullPathName, CUID);
+      Directory = "";
+    else {
+      FullPathName = Directory;
+      sys::path::append(FullPathName, Filename);
+      Directory = "";
+      Filename = FullPathName;
+    }
   }
 
   OS << "\t.file\t" << FileNo << ' ';
@@ -864,11 +878,8 @@ unsigned MCAsmStreamer::EmitDwarfFileDirective(unsigned FileNo,
   }
   PrintQuotedString(Filename, OS);
   EmitEOL();
-  // All .file will belong to a single CUID.
-  CUID = 0;
 
-  return this->MCStreamer::EmitDwarfFileDirective(FileNo, Directory, Filename,
-                                                  CUID);
+  return FileNo;
 }
 
 void MCAsmStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 72ecfa6cb45..edeee20ab47 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -287,6 +287,7 @@ std::pair<MCSymbol *, MCSymbol *> MCDwarfLineTableHeader::Emit(MCStreamer *MCOS)
 
   // Second the file table.
   for (unsigned i = 1; i < MCDwarfFiles.size(); i++) {
+    assert(!MCDwarfFiles[i].Name.empty());
     MCOS->EmitBytes(MCDwarfFiles[i].Name); // FileName
     MCOS->EmitBytes(StringRef("\0", 1)); // the null term. of the string
     // the Directory num
@@ -331,14 +332,19 @@ const MCSymbol *MCDwarfLineTable::EmitCU(MCStreamer *MCOS) const {
   return LineStartSym;
 }
 
-unsigned MCDwarfLineTable::getFile(StringRef Directory, StringRef FileName,
+unsigned MCDwarfLineTable::getFile(StringRef &Directory, StringRef &FileName,
                                    unsigned FileNumber) {
   return Header.getFile(Directory, FileName, FileNumber);
 }
 
-unsigned MCDwarfLineTableHeader::getFile(StringRef Directory,
-                                         StringRef FileName,
+unsigned MCDwarfLineTableHeader::getFile(StringRef &Directory,
+                                         StringRef &FileName,
                                          unsigned FileNumber) {
+  if (FileName.empty()) {
+    FileName = "<stdin>";
+    Directory = "";
+  }
+  assert(!FileName.empty());
   if (FileNumber == 0) {
     FileNumber = SourceIdMap.size() + 1;
     assert((MCDwarfFiles.empty() || FileNumber == MCDwarfFiles.size()) &&