8 files changed, 27 insertions, 15 deletions
diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index ba09bccfe1c..63348c094c9 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -573,6 +573,8 @@ def fblocks_runtime_optional : Flag<["-"], "fblocks-runtime-optional">,
   HelpText<"Weakly link in the blocks runtime">;
 def fexternc_nounwind : Flag<["-"], "fexternc-nounwind">,
   HelpText<"Assume all functions with C linkage do not unwind">;
+def enable_split_dwarf : Flag<["-"], "enable-split-dwarf">,
+  HelpText<"Use split dwarf/Fission">;
 def split_dwarf_file : Separate<["-"], "split-dwarf-file">,
   HelpText<"File name to use for split dwarf debug info output">;
 def fno_wchar : Flag<["-"], "fno-wchar">,
diff --git a/clang/include/clang/Frontend/CodeGenOptions.def b/clang/include/clang/Frontend/CodeGenOptions.def
index 9565b22e705..0b7d466ab3d 100644
--- a/clang/include/clang/Frontend/CodeGenOptions.def
+++ b/clang/include/clang/Frontend/CodeGenOptions.def
@@ -199,6 +199,7 @@ CODEGENOPT(DebugTypeExtRefs, 1, 0) ///< Whether or not debug info should contain
 CODEGENOPT(DebugExplicitImport, 1, 0)  ///< Whether or not debug info should
                                        ///< contain explicit imports for
                                        ///< anonymous namespaces
+CODEGENOPT(EnableSplitDwarf, 1, 0) ///< Whether to enable split DWARF
 CODEGENOPT(SplitDwarfInlining, 1, 1) ///< Whether to include inlining info in the
                                      ///< skeleton CU to allow for symbolication
 				     ///< of inline stack frames without .dwo files.
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 20059d922f9..7de0eaca19a 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -407,6 +407,8 @@ static void initTargetOptions(llvm::TargetOptions &Options,
   Options.EmulatedTLS = CodeGenOpts.EmulatedTLS;
   Options.DebuggerTuning = CodeGenOpts.getDebuggerTuning();
 
+  if (CodeGenOpts.EnableSplitDwarf)
+    Options.MCOptions.SplitDwarfFile = CodeGenOpts.SplitDwarfFile;
   Options.MCOptions.MCRelaxAll = CodeGenOpts.RelaxAll;
   Options.MCOptions.MCSaveTempLabels = CodeGenOpts.SaveTempLabels;
   Options.MCOptions.MCUseDwarfDirectory = !CodeGenOpts.NoDwarfDirectoryAsm;
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 2f6a2b95fb6..dd32a44393c 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -528,12 +528,14 @@ void CGDebugInfo::CreateCompileUnit() {
   // Create new compile unit.
   // FIXME - Eliminate TheCU.
   TheCU = DBuilder.createCompileUnit(
-      LangTag, DBuilder.createFile(remapDIPath(MainFileName),
-                                   remapDIPath(getCurrentDirname()), CSKind,
-                                   Checksum),
+      LangTag,
+      DBuilder.createFile(remapDIPath(MainFileName),
+                          remapDIPath(getCurrentDirname()), CSKind, Checksum),
       Producer, LO.Optimize, CGM.getCodeGenOpts().DwarfDebugFlags, RuntimeVers,
-      CGM.getCodeGenOpts().SplitDwarfFile, EmissionKind, 0 /* DWOid */,
-      CGM.getCodeGenOpts().SplitDwarfInlining,
+      CGM.getCodeGenOpts().EnableSplitDwarf
+          ? ""
+          : CGM.getCodeGenOpts().SplitDwarfFile,
+      EmissionKind, 0 /* DWOid */, CGM.getCodeGenOpts().SplitDwarfInlining,
       CGM.getCodeGenOpts().DebugInfoForProfiling);
 }
 
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 49708e7d724..6e1e4ccf44f 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2778,8 +2778,7 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-fno-split-dwarf-inlining");
     if (DebugInfoKind == codegenoptions::NoDebugInfo)
       DebugInfoKind = codegenoptions::LimitedDebugInfo;
-    CmdArgs.push_back("-backend-option");
-    CmdArgs.push_back("-split-dwarf=Enable");
+    CmdArgs.push_back("-enable-split-dwarf");
   }
 
   // After we've dealt with all combinations of things that could
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 0e0eb40eb33..8cdb8298ee9 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -519,6 +519,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   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.EnableSplitDwarf = Args.hasArg(OPT_enable_split_dwarf);
   Opts.SplitDwarfFile = Args.getLastArgValue(OPT_split_dwarf_file);
   Opts.SplitDwarfInlining = !Args.hasArg(OPT_fno_split_dwarf_inlining);
   Opts.DebugTypeExtRefs = Args.hasArg(OPT_dwarf_ext_refs);
diff --git a/clang/test/CodeGen/split-debug-filename.c b/clang/test/CodeGen/split-debug-filename.c
index 43daeada96a..9ca7b0f3287 100644
--- a/clang/test/CodeGen/split-debug-filename.c
+++ b/clang/test/CodeGen/split-debug-filename.c
@@ -1,7 +1,12 @@
 // 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
 int main (void) {
   return 0;
 }
 
 // Testing to ensure that the dwo name gets output into the compile unit.
 // CHECK: !DICompileUnit({{.*}}, splitDebugFilename: "foo.dwo"
+
+// Testing to ensure that the dwo name is not output into the compile unit if
+// it's for vanilla split-dwarf rather than split-dwarf for implicit modules.
+// VANILLA-NOT: splitDebugFilename
diff --git a/clang/test/Driver/split-debug.c b/clang/test/Driver/split-debug.c
index eaa1e990c04..c12164b4e2f 100644
--- a/clang/test/Driver/split-debug.c
+++ b/clang/test/Driver/split-debug.c
@@ -36,53 +36,53 @@
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -gmlt -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-GMLT-WITH-SPLIT < %t %s
 //
-// CHECK-GMLT-WITH-SPLIT: "-split-dwarf=Enable"
+// CHECK-GMLT-WITH-SPLIT: "-enable-split-dwarf"
 // CHECK-GMLT-WITH-SPLIT: "-debug-info-kind=line-tables-only"
 // CHECK-GMLT-WITH-SPLIT: "-split-dwarf-file"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gmlt -gsplit-dwarf -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-WITH-GMLT < %t %s
 //
-// CHECK-SPLIT-WITH-GMLT: "-split-dwarf=Enable"
+// CHECK-SPLIT-WITH-GMLT: "-enable-split-dwarf"
 // CHECK-SPLIT-WITH-GMLT: "-debug-info-kind=line-tables-only"
 // CHECK-SPLIT-WITH-GMLT: "-split-dwarf-file"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-WITH-NOINL < %t %s
 //
-// CHECK-SPLIT-WITH-NOINL: "-split-dwarf=Enable"
+// CHECK-SPLIT-WITH-NOINL: "-enable-split-dwarf"
 // CHECK-SPLIT-WITH-NOINL: "-debug-info-kind=limited"
 // CHECK-SPLIT-WITH-NOINL: "-split-dwarf-file"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -gmlt -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-GMLT-OVER-SPLIT < %t %s
 //
-// CHECK-GMLT-OVER-SPLIT-NOT: "-split-dwarf=Enable"
+// 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"
 
 // 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: "-split-dwarf=Enable" "-debug-info-kind=limited"
+// CHECK-SPLIT-OVER-GMLT: "-enable-split-dwarf" "-debug-info-kind=limited"
 // CHECK-SPLIT-OVER-GMLT: "-split-dwarf-file"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -g0 -fno-split-dwarf-inlining -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-G0-OVER-SPLIT < %t %s
 //
-// CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf=Enable"
+// CHECK-G0-OVER-SPLIT-NOT: "-enable-split-dwarf"
 // CHECK-G0-OVER-SPLIT-NOT: "-debug-info-kind
 // CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf-file"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -gsplit-dwarf -g0 -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-G0-OVER-SPLIT < %t %s
 //
-// CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf=Enable"
+// CHECK-G0-OVER-SPLIT-NOT: "-enable-split-dwarf"
 // CHECK-G0-OVER-SPLIT-NOT: "-debug-info-kind
 // CHECK-G0-OVER-SPLIT-NOT: "-split-dwarf-file"
 
 // RUN: %clang -target x86_64-unknown-linux-gnu -g0 -gsplit-dwarf -S -### %s 2> %t
 // RUN: FileCheck -check-prefix=CHECK-SPLIT-OVER-G0 < %t %s
 //
-// CHECK-SPLIT-OVER-G0: "-split-dwarf=Enable" "-debug-info-kind=limited"
+// CHECK-SPLIT-OVER-G0: "-enable-split-dwarf" "-debug-info-kind=limited"
 // CHECK-SPLIT-OVER-G0: "-split-dwarf-file"