5 files changed, 30 insertions, 7 deletions
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 2238c89f83..0a92710ff4 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -123,8 +123,6 @@ llvm::DICompileUnit CGDebugInfo::getOrCreateCompileUnit(SourceLocation Loc) {
     CLANG_VENDOR
 #endif
     "clang " CLANG_VERSION_STRING;
-  bool isOptimized = LO.Optimize;
-  const char *Flags = "";   // FIXME: Encode command line options.
 
   // Figure out which version of the ObjC runtime we have.
   unsigned RuntimeVers = 0;
@@ -132,11 +130,9 @@ llvm::DICompileUnit CGDebugInfo::getOrCreateCompileUnit(SourceLocation Loc) {
     RuntimeVers = LO.ObjCNonFragileABI ? 2 : 1;
 
   // Create new compile unit.
-  return Unit = DebugFactory.CreateCompileUnit(LangTag, 
-                                               AbsFileName.getLast(),
-                                               AbsFileName.getDirname(),
-                                               Producer, isMain,
-                                               isOptimized, Flags, RuntimeVers);
+  return Unit = DebugFactory.CreateCompileUnit(
+    LangTag, AbsFileName.getLast(), AbsFileName.getDirname(), Producer, isMain,
+    LO.Optimize, CGM.getCodeGenOpts().DwarfDebugFlags, RuntimeVers);
 }
 
 /// CreateType - Get the Basic type from the cache or create a new
diff --git a/lib/Driver/ToolChains.cpp b/lib/Driver/ToolChains.cpp
index 420573dea2..0c2db8a87c 100644
--- a/lib/Driver/ToolChains.cpp
+++ b/lib/Driver/ToolChains.cpp
@@ -526,6 +526,12 @@ bool Darwin::IsUnwindTablesDefault() const {
   return getArchName() == "x86_64";
 }
 
+bool Darwin::UseDwarfDebugFlags() const {
+  if (const char *S = ::getenv("RC_DEBUG_OPTIONS"))
+    return S[0] != '\0';
+  return false;
+}
+
 const char *Darwin::GetDefaultRelocationModel() const {
   return "pic";
 }
diff --git a/lib/Driver/ToolChains.h b/lib/Driver/ToolChains.h
index fcd96f1e5c..be36344f0c 100644
--- a/lib/Driver/ToolChains.h
+++ b/lib/Driver/ToolChains.h
@@ -154,6 +154,8 @@ public:
   virtual const char *GetDefaultRelocationModel() const;
   virtual const char *GetForcedPicModel() const;
 
+  virtual bool UseDwarfDebugFlags() const;
+
   /// }
 };
 
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 55008e3bbb..d3c1b310ed 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -1109,6 +1109,20 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   const char *Exec =
     Args.MakeArgString(getToolChain().GetProgramPath(C, "clang"));
+
+  // Optionally embed the -cc1 level arguments into the debug info, for build
+  // analysis.
+  if (getToolChain().UseDwarfDebugFlags()) {
+    llvm::SmallString<256> Flags;
+    Flags += Exec;
+    for (unsigned i = 0, e = CmdArgs.size(); i != e; ++i) {
+      Flags += " ";
+      Flags += CmdArgs[i];
+    }
+    CmdArgs.push_back("-dwarf-debug-flags");
+    CmdArgs.push_back(Args.MakeArgString(Flags.str()));
+  }
+
   Dest.addCommand(new Command(JA, *this, Exec, CmdArgs));
 
   // Explicitly warn that these options are unsupported, even though
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 0a592b2e5a..414705716b 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -122,6 +122,10 @@ static void CodeGenOptsToArgs(const CodeGenOptions &Opts,
     Res.push_back("-disable-llvm-optzns");
   if (Opts.DisableRedZone)
     Res.push_back("-disable-red-zone");
+  if (!Opts.DwarfDebugFlags.empty()) {
+    Res.push_back("-dwarf-debug-flags");
+    Res.push_back(Opts.DwarfDebugFlags);
+  }
   if (!Opts.MergeAllConstants)
     Res.push_back("-fno-merge-all-constants");
   if (Opts.NoCommon)
@@ -749,6 +753,7 @@ static void ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
   Opts.DebugInfo = Args.hasArg(OPT_g);
   Opts.DisableLLVMOpts = Args.hasArg(OPT_disable_llvm_optzns);
   Opts.DisableRedZone = Args.hasArg(OPT_disable_red_zone);
+  Opts.DwarfDebugFlags = getLastArgValue(Args, OPT_dwarf_debug_flags);
   Opts.MergeAllConstants = !Args.hasArg(OPT_fno_merge_all_constants);
   Opts.NoCommon = Args.hasArg(OPT_fno_common);
   Opts.NoImplicitFloat = Args.hasArg(OPT_no_implicit_float);