3 files changed, 35 insertions, 4 deletions
diff --git a/llvm/lib/MC/MCContext.cpp b/llvm/lib/MC/MCContext.cpp
index e4f90f4987a..b601ab24434 100644
--- a/llvm/lib/MC/MCContext.cpp
+++ b/llvm/lib/MC/MCContext.cpp
@@ -535,6 +535,26 @@ MCSubtargetInfo &MCContext::getSubtargetCopy(const MCSubtargetInfo &STI) {
   return *new (MCSubtargetAllocator.Allocate()) MCSubtargetInfo(STI);
 }
 
+void MCContext::addDebugPrefixMapEntry(const std::string &From,
+                                       const std::string &To) {
+  DebugPrefixMap.insert(std::make_pair(From, To));
+}
+
+void MCContext::RemapDebugPath(std::string *Path) {
+  for (const auto &Entry : DebugPrefixMap)
+    if (StringRef(*Path).startswith(Entry.first)) {
+      std::string RemappedPath =
+          (Twine(Entry.second) + Path->substr(Entry.first.size())).str();
+      Path->swap(RemappedPath);
+    }
+}
+
+void MCContext::RemapCompilationDir() {
+  std::string CompDir = CompilationDir.str();
+  RemapDebugPath(&CompDir);
+  CompilationDir = CompDir;
+}
+
 //===----------------------------------------------------------------------===//
 // Dwarf Management
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/MC/MCDwarf.cpp b/llvm/lib/MC/MCDwarf.cpp
index 37e1263be65..1d33d9947be 100644
--- a/llvm/lib/MC/MCDwarf.cpp
+++ b/llvm/lib/MC/MCDwarf.cpp
@@ -250,8 +250,11 @@ void MCDwarfLineTable::Emit(MCObjectStreamer *MCOS,
   MCOS->SwitchSection(context.getObjectFileInfo()->getDwarfLineSection());
 
   // Handle the rest of the Compile Units.
-  for (const auto &CUIDTablePair : LineTables)
-    CUIDTablePair.second.EmitCU(MCOS, Params, LineStr);
+  for (const auto &CUIDTablePair : LineTables) {
+    auto &LineTable = context.getMCDwarfLineTable(CUIDTablePair.first);
+    LineTable.RemapDwarfDirs(MCOS->getContext());
+    LineTable.EmitCU(MCOS, Params, LineStr);
+  }
 
   if (LineStr)
     LineStr->emitSection(MCOS);
@@ -394,13 +397,13 @@ void MCDwarfLineTableHeader::emitV5FileDirTables(
   if (LineStr) {
     // Record path strings, emit references here.
     LineStr->emitRef(MCOS, CompDir);
-    for (auto &Dir : MCDwarfDirs)
+    for (const auto &Dir : MCDwarfDirs)
       LineStr->emitRef(MCOS, Dir);
   } else {
     // The list of directory paths.  Compilation directory comes first.
     MCOS->EmitBytes(CompDir);
     MCOS->EmitBytes(StringRef("\0", 1));
-    for (auto &Dir : MCDwarfDirs) {
+    for (const auto &Dir : MCDwarfDirs) {
       MCOS->EmitBytes(Dir);                // The DirectoryName, and...
       MCOS->EmitBytes(StringRef("\0", 1)); // its null terminator.
     }
@@ -631,6 +634,11 @@ MCDwarfLineTableHeader::tryGetFile(StringRef &Directory,
   return FileNumber;
 }
 
+void MCDwarfLineTable::RemapDwarfDirs(MCContext &Context) {
+  for (auto &Dir : Header.MCDwarfDirs)
+    Context.RemapDebugPath(&Dir);
+}
+
 /// Utility function to emit the encoding to a streamer.
 void MCDwarfLineAddr::Emit(MCStreamer *MCOS, MCDwarfLineTableParams Params,
                            int64_t LineDelta, uint64_t AddrDelta) {
diff --git a/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 432f4c242a8..8122af459b7 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/lib/MC/MCObjectStreamer.cpp
@@ -661,6 +661,9 @@ void MCObjectStreamer::EmitFileDirective(StringRef Filename) {
 }
 
 void MCObjectStreamer::FinishImpl() {
+  // Remap the compilation directory before emitting.
+  getContext().RemapCompilationDir();
+
   // If we are generating dwarf for assembly source files dump out the sections.
   if (getContext().getGenDwarfForAssembly())
     MCGenDwarfInfo::Emit(this);