Index: cfe/trunk/include/clang/Basic/CodeGenOptions.h
===================================================================
--- cfe/trunk/include/clang/Basic/CodeGenOptions.h
+++ cfe/trunk/include/clang/Basic/CodeGenOptions.h
@@ -185,8 +185,11 @@
   /// file, for example with -save-temps.
   std::string MainFileName;
 
-  /// The name for the split debug info file that we'll break out. This is used
-  /// in the backend for setting the name in the skeleton cu.
+  /// The name for the split debug info file used for the DW_AT_[GNU_]dwo_name
+  /// attribute in the skeleton CU.
+  std::string SplitDwarfFile;
+
+  /// Output filename for the split debug info, not used in the skeleton CU.
   std::string SplitDwarfOutput;
 
   /// The name of the relocation model to use.
Index: cfe/trunk/include/clang/Driver/CC1Options.td
===================================================================
--- cfe/trunk/include/clang/Driver/CC1Options.td
+++ cfe/trunk/include/clang/Driver/CC1Options.td
@@ -696,6 +696,8 @@
   HelpText<"Use DWARF fission in 'split' mode">;
 def enable_split_dwarf_EQ : Joined<["-"], "enable-split-dwarf=">,
   HelpText<"Set DWARF fission mode to either 'split' or 'single'">, Values<"split,single">;
+def split_dwarf_file : Separate<["-"], "split-dwarf-file">,
+  HelpText<"Name of the split dwarf debug info file to encode in the object file">;
 def fno_wchar : Flag<["-"], "fno-wchar">,
   HelpText<"Disable C++ builtin type wchar_t">;
 def fconstant_string_class : Separate<["-"], "fconstant-string-class">,
Index: cfe/trunk/lib/CodeGen/BackendUtil.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp
@@ -472,7 +472,7 @@
   Options.EmitAddrsig = CodeGenOpts.Addrsig;
 
   if (CodeGenOpts.getSplitDwarfMode() != CodeGenOptions::NoFission)
-    Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfOutput;
+    Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
@@ -1428,7 +1428,8 @@
   Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
   Conf.RemarksFilename = CGOpts.OptRecordFile;
   Conf.RemarksPasses = CGOpts.OptRecordPasses;
-  Conf.DwoPath = CGOpts.SplitDwarfOutput;
+  Conf.SplitDwarfFile = CGOpts.SplitDwarfFile;
+  Conf.SplitDwarfOutput = CGOpts.SplitDwarfOutput;
   switch (Action) {
   case Backend_EmitNothing:
     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
Index: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
+++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
@@ -616,7 +616,7 @@
       CGOpts.DwarfDebugFlags, RuntimeVers,
       (CGOpts.getSplitDwarfMode() != CodeGenOptions::NoFission)
           ? ""
-          : CGOpts.SplitDwarfOutput,
+          : CGOpts.SplitDwarfFile,
       EmissionKind, DwoId, CGOpts.SplitDwarfInlining,
       CGOpts.DebugInfoForProfiling,
       CGM.getTarget().getTriple().isNVPTX()
Index: cfe/trunk/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- cfe/trunk/lib/Driver/ToolChains/Clang.cpp
+++ cfe/trunk/lib/Driver/ToolChains/Clang.cpp
@@ -4108,11 +4108,14 @@
                     TC.getTriple().isOSBinFormatELF() &&
                     (isa<AssembleJobAction>(JA) || isa<CompileJobAction>(JA) ||
                      isa<BackendJobAction>(JA));
-  const char *SplitDWARFOut;
   if (SplitDWARF) {
-    CmdArgs.push_back("-split-dwarf-output");
-    SplitDWARFOut = SplitDebugName(Args, Input, Output);
+    const char *SplitDWARFOut = SplitDebugName(Args, Input, Output);
+    CmdArgs.push_back("-split-dwarf-file");
     CmdArgs.push_back(SplitDWARFOut);
+    if (DwarfFission == DwarfFissionKind::Split) {
+      CmdArgs.push_back("-split-dwarf-output");
+      CmdArgs.push_back(SplitDWARFOut);
+    }
   }
 
   // Pass the linker version in use.
Index: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
===================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp
@@ -726,6 +726,7 @@
   Opts.MacroDebugInfo = Args.hasArg(OPT_debug_info_macro);
   Opts.WholeProgramVTables = Args.hasArg(OPT_fwhole_program_vtables);
   Opts.LTOVisibilityPublicStd = Args.hasArg(OPT_flto_visibility_public_std);
+  Opts.SplitDwarfFile = Args.getLastArgValue(OPT_split_dwarf_file);
   Opts.SplitDwarfOutput = Args.getLastArgValue(OPT_split_dwarf_output);
   Opts.SplitDwarfInlining = !Args.hasArg(OPT_fno_split_dwarf_inlining);
 
Index: cfe/trunk/test/CodeGen/split-debug-filename.c
===================================================================
--- cfe/trunk/test/CodeGen/split-debug-filename.c
+++ cfe/trunk/test/CodeGen/split-debug-filename.c
@@ -1,7 +1,7 @@
 // REQUIRES: x86-registered-target
-// RUN: %clang_cc1 -debug-info-kind=limited -split-dwarf-output foo.dwo -S -emit-llvm -o - %s | FileCheck %s
-// RUN: %clang_cc1 -debug-info-kind=limited -enable-split-dwarf -split-dwarf-output foo.dwo -S -emit-llvm -o - %s | FileCheck --check-prefix=VANILLA %s
-// RUN: %clang_cc1 -triple x86_64-unknown-linux -debug-info-kind=limited -enable-split-dwarf -split-dwarf-output %t.dwo -emit-obj -o - %s | llvm-readobj -S - | FileCheck --check-prefix=O %s
+// RUN: %clang_cc1 -debug-info-kind=limited -split-dwarf-file foo.dwo -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -debug-info-kind=limited -enable-split-dwarf -split-dwarf-file foo.dwo -S -emit-llvm -o - %s | FileCheck --check-prefix=VANILLA %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux -debug-info-kind=limited -enable-split-dwarf -split-dwarf-file %t.dwo -split-dwarf-output %t.dwo -emit-obj -o - %s | llvm-readobj -S - | FileCheck --check-prefix=O %s
 // RUN: llvm-readobj -S %t.dwo | FileCheck --check-prefix=DWO %s
 
 int main (void) {
Index: cfe/trunk/test/CodeGen/split-debug-output.c
===================================================================
--- cfe/trunk/test/CodeGen/split-debug-output.c
+++ cfe/trunk/test/CodeGen/split-debug-output.c
@@ -0,0 +1,7 @@
+// REQUIRES: x86-registered-target
+// RUN: %clang_cc1 -triple x86_64-unknown-linux -debug-info-kind=limited -enable-split-dwarf -split-dwarf-file foo.dwo -split-dwarf-output %t -emit-obj -o - %s | llvm-dwarfdump -debug-info - | FileCheck %s
+// RUN: llvm-dwarfdump -debug-info %t | FileCheck %s
+
+int f() { return 0; }
+
+// CHECK: DW_AT_GNU_dwo_name ("foo.dwo")
Index: cfe/trunk/test/CodeGen/split-debug-single-file.c
===================================================================
--- cfe/trunk/test/CodeGen/split-debug-single-file.c
+++ cfe/trunk/test/CodeGen/split-debug-single-file.c
@@ -2,19 +2,19 @@
 
 // Testing to ensure -enable-split-dwarf=single allows to place .dwo sections into regular output object.
 //  RUN: %clang_cc1 -debug-info-kind=limited -triple x86_64-unknown-linux \
-//  RUN:   -enable-split-dwarf=single -split-dwarf-output %t.o -emit-obj -o %t.o %s -fno-experimental-new-pass-manager
+//  RUN:   -enable-split-dwarf=single -split-dwarf-file %t.o -emit-obj -o %t.o %s -fno-experimental-new-pass-manager
 //  RUN: llvm-readobj -S %t.o | FileCheck --check-prefix=MODE-SINGLE %s
 //  RUN: %clang_cc1 -debug-info-kind=limited -triple x86_64-unknown-linux \
-//  RUN:   -enable-split-dwarf=single -split-dwarf-output %t.o -emit-obj -o %t.o %s -fexperimental-new-pass-manager
+//  RUN:   -enable-split-dwarf=single -split-dwarf-file %t.o -emit-obj -o %t.o %s -fexperimental-new-pass-manager
 //  RUN: llvm-readobj -S %t.o | FileCheck --check-prefix=MODE-SINGLE %s
 //  MODE-SINGLE: .dwo
 
 // Testing to ensure -enable-split-dwarf=split does not place .dwo sections into regular output object.
 //  RUN: %clang_cc1 -debug-info-kind=limited -triple x86_64-unknown-linux \
-//  RUN:   -enable-split-dwarf=split -split-dwarf-output %t.o -emit-obj -o %t.o %s -fno-experimental-new-pass-manager
+//  RUN:   -enable-split-dwarf=split -split-dwarf-file %t.dwo -split-dwarf-output %t.dwo -emit-obj -o %t.o %s -fno-experimental-new-pass-manager
 //  RUN: llvm-readobj -S %t.o | FileCheck --check-prefix=MODE-SPLIT %s
 //  RUN: %clang_cc1 -debug-info-kind=limited -triple x86_64-unknown-linux \
-//  RUN:   -enable-split-dwarf=split -split-dwarf-output %t.o -emit-obj -o %t.o %s -fexperimental-new-pass-manager
+//  RUN:   -enable-split-dwarf=split -split-dwarf-file %t.dwo -split-dwarf-output %t.dwo -emit-obj -o %t.o %s -fexperimental-new-pass-manager
 //  RUN: llvm-readobj -S %t.o | FileCheck --check-prefix=MODE-SPLIT %s
 //  MODE-SPLIT-NOT: .dwo
 
Index: cfe/trunk/test/CodeGen/thinlto-split-dwarf.c
===================================================================
--- cfe/trunk/test/CodeGen/thinlto-split-dwarf.c
+++ cfe/trunk/test/CodeGen/thinlto-split-dwarf.c
@@ -10,12 +10,14 @@
 
 // RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu \
 // RUN:   -emit-obj -fthinlto-index=%t.o.thinlto.bc \
-// RUN:   -o %t.native.o -split-dwarf-output %t.native.dwo -x ir %t.o
+// RUN:   -o %t.native.o -split-dwarf-file %t.file.dwo \
+// RUN:   -split-dwarf-output %t.output.dwo -x ir %t.o
 
-// RUN: llvm-readobj -S %t.native.o | FileCheck --check-prefix=O %s
-// RUN: llvm-readobj -S %t.native.dwo | FileCheck --check-prefix=DWO %s
+// RUN: llvm-dwarfdump %t.native.o | FileCheck --check-prefix=O %s
+// RUN: llvm-dwarfdump %t.output.dwo | FileCheck --check-prefix=DWO %s
 
-// O-NOT: .dwo
-// DWO: .dwo
+// O: DW_AT_GNU_dwo_name ("{{.*}}.file.dwo")
+// O-NOT: DW_TAG_subprogram
+// DWO: DW_TAG_subprogram
 
 int main() {}
Index: cfe/trunk/test/Driver/split-debug.c
===================================================================
--- cfe/trunk/test/Driver/split-debug.c
+++ cfe/trunk/test/Driver/split-debug.c
@@ -3,7 +3,7 @@
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -c -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-ACTIONS < %t %s
 //
-// CHECK-ACTIONS: "-split-dwarf-output" "split-debug.dwo"
+// CHECK-ACTIONS: "-split-dwarf-file" "split-debug.dwo" "-split-dwarf-output" "split-debug.dwo"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -c -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-ACTIONS < %t %s
@@ -14,12 +14,14 @@
 // RUN: FileCheck -check-prefix=CHECK-ACTIONS-SINGLE-SPLIT < %t %s
 //
 // CHECK-ACTIONS-SINGLE-SPLIT: "-enable-split-dwarf=single"
-// CHECK-ACTIONS-SINGLE-SPLIT: "-split-dwarf-output" "split-debug.o"
+// CHECK-ACTIONS-SINGLE-SPLIT: "-split-dwarf-file" "split-debug.o"
+// CHECK-ACTIONS-SINGLE-SPLIT-NOT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf=single -c -### -o %tfoo.o %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SINGLE-SPLIT-FILENAME < %t %s
 //
-// CHECK-SINGLE-SPLIT-FILENAME: "-split-dwarf-output" "{{.*}}foo.o"
+// CHECK-SINGLE-SPLIT-FILENAME: "-split-dwarf-file" "{{.*}}foo.o"
+// CHECK-SINGLE-SPLIT-FILENAME-NOT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-macosx -gsplit-dwarf -c -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-NO-ACTIONS < %t %s
@@ -41,7 +43,7 @@
 // RUN: %clang -target amdgcn-amd-amdhsa -gsplit-dwarf -c -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-OPTION < %t %s
 //
-// CHECK-OPTION: "-split-dwarf-output" "split-debug.dwo"
+// CHECK-OPTION: "-split-dwarf-file" "split-debug.dwo" "-split-dwarf-output" "split-debug.dwo"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-ASM < %t %s
@@ -58,6 +60,7 @@
 //
 // CHECK-GMLT-WITH-SPLIT: "-enable-split-dwarf"
 // CHECK-GMLT-WITH-SPLIT: "-debug-info-kind=line-tables-only"
+// CHECK-GMLT-WITH-SPLIT: "-split-dwarf-file"
 // CHECK-GMLT-WITH-SPLIT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -g -fno-split-dwarf-inlining -S -### %s 2> %t
@@ -86,12 +89,14 @@
 //
 // CHECK-GMLT-OVER-SPLIT-NOT: "-enable-split-dwarf"
 // CHECK-GMLT-OVER-SPLIT: "-debug-info-kind=line-tables-only"
+// CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf-file"
 // CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gmlt -gsplit-dwarf -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-OVER-GMLT < %t %s
 //
 // CHECK-SPLIT-OVER-GMLT: "-enable-split-dwarf" "-debug-info-kind=limited"
+// CHECK-SPLIT-OVER-GMLT: "-split-dwarf-file"
 // CHECK-SPLIT-OVER-GMLT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -g0 -fno-split-dwarf-inlining -S -### %s 2> %t
@@ -99,6 +104,7 @@
 //
 // CHECK-G0-OVER-SPLIT-NOT: "-enable-split-dwarf"
 // CHECK-G0-OVER-SPLIT-NOT: "-debug-info-kind
+// CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf-file"
 // CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -g0 -S -### %s 2> %t
@@ -108,6 +114,7 @@
 //
 // CHECK-G0-OVER-SPLIT-NOT: "-enable-split-dwarf"
 // CHECK-G0-OVER-SPLIT-NOT: "-debug-info-kind
+// CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf-file"
 // CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf-output"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -g0 -gsplit-dwarf -S -### %s 2> %t
@@ -116,4 +123,5 @@
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-OVER-G0 < %t %s
 //
 // CHECK-SPLIT-OVER-G0: "-enable-split-dwarf" "-debug-info-kind=limited"
+// CHECK-SPLIT-OVER-G0: "-split-dwarf-file"
 // CHECK-SPLIT-OVER-G0: "-split-dwarf-output"
Index: llvm/trunk/include/llvm/LTO/Config.h
===================================================================
--- llvm/trunk/include/llvm/LTO/Config.h
+++ llvm/trunk/include/llvm/LTO/Config.h
@@ -88,10 +88,16 @@
   /// The directory to store .dwo files.
   std::string DwoDir;
 
+  /// The name for the split debug info file used for the DW_AT_[GNU_]dwo_name
+  /// attribute in the skeleton CU. This should generally only be used when
+  /// running an individual backend directly via thinBackend(), as otherwise
+  /// all objects would use the same .dwo file. Not used as output path.
+  std::string SplitDwarfFile;
+
   /// The path to write a .dwo file to. This should generally only be used when
   /// running an individual backend directly via thinBackend(), as otherwise
-  /// all .dwo files will be written to the same path.
-  std::string DwoPath;
+  /// all .dwo files will be written to the same path. Not used in skeleton CU.
+  std::string SplitDwarfOutput;
 
   /// Optimization remarks file path.
   std::string RemarksFilename = "";
Index: llvm/trunk/lib/LTO/LTOBackend.cpp
===================================================================
--- llvm/trunk/lib/LTO/LTOBackend.cpp
+++ llvm/trunk/lib/LTO/LTOBackend.cpp
@@ -314,7 +314,7 @@
     return;
 
   std::unique_ptr<ToolOutputFile> DwoOut;
-  SmallString<1024> DwoFile(Conf.DwoPath);
+  SmallString<1024> DwoFile(Conf.SplitDwarfOutput);
   if (!Conf.DwoDir.empty()) {
     std::error_code EC;
     if (auto EC = llvm::sys::fs::create_directories(Conf.DwoDir))
@@ -323,11 +323,12 @@
 
     DwoFile = Conf.DwoDir;
     sys::path::append(DwoFile, std::to_string(Task) + ".dwo");
-  }
+    TM->Options.MCOptions.SplitDwarfFile = DwoFile.str().str();
+  } else
+    TM->Options.MCOptions.SplitDwarfFile = Conf.SplitDwarfFile;
 
   if (!DwoFile.empty()) {
     std::error_code EC;
-    TM->Options.MCOptions.SplitDwarfFile = DwoFile.str().str();
     DwoOut = llvm::make_unique<ToolOutputFile>(DwoFile, EC, sys::fs::F_None);
     if (EC)
       report_fatal_error("Failed to open " + DwoFile + ": " + EC.message());