3 files changed, 18 insertions, 8 deletions
diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index afcb9e5c505..5754bb63dd7 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -272,6 +272,9 @@ static void addSymbolRewriterPass(const CodeGenOptions &Opts,
 }
 
 void EmitAssemblyHelper::CreatePasses() {
+  if (CodeGenOpts.DisableLLVMPasses)
+    return;
+
   unsigned OptLevel = CodeGenOpts.OptimizationLevel;
   CodeGenOptions::InliningMethod Inlining = CodeGenOpts.getInlining();
 
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index d4a307b62a4..40643ccb67e 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -4800,7 +4800,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   // Forward -Xclang arguments to -cc1, and -mllvm arguments to the LLVM option
   // parser.
   Args.AddAllArgValues(CmdArgs, options::OPT_Xclang);
-  bool OptDisabled = false;
   for (const Arg *A : Args.filtered(options::OPT_mllvm)) {
     A->claim();
 
@@ -4808,17 +4807,15 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     // it and developers have been trained to spell it with -mllvm.
     if (StringRef(A->getValue(0)) == "-disable-llvm-optzns") {
       CmdArgs.push_back("-disable-llvm-optzns");
-      OptDisabled = true;
     } else
       A->render(Args, CmdArgs);
   }
 
   // With -save-temps, we want to save the unoptimized bitcode output from the
-  // CompileJobAction, so disable optimizations if they are not already
-  // disabled.
-  if (C.getDriver().isSaveTempsEnabled() && !OptDisabled &&
-      isa<CompileJobAction>(JA))
-    CmdArgs.push_back("-disable-llvm-optzns");
+  // CompileJobAction, use -disable-llvm-passes to get pristine IR generated
+  // by the frontend.
+  if (C.getDriver().isSaveTempsEnabled() && isa<CompileJobAction>(JA))
+    CmdArgs.push_back("-disable-llvm-passes");
 
   if (Output.getType() == types::TY_Dependencies) {
     // Handled with other dependency code.
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index f325144fd08..e4cfba3b544 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -426,6 +426,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     Opts.EmitLLVMUseLists = A->getOption().getID() == OPT_emit_llvm_uselists;
 
   Opts.DisableLLVMOpts = Args.hasArg(OPT_disable_llvm_optzns);
+  Opts.DisableLLVMPasses = Args.hasArg(OPT_disable_llvm_passes);
   Opts.DisableRedZone = Args.hasArg(OPT_disable_red_zone);
   Opts.ForbidGuardVariables = Args.hasArg(OPT_fforbid_guard_variables);
   Opts.UseRegisterSizedBitfieldAccess = Args.hasArg(
@@ -1887,7 +1888,16 @@ bool CompilerInvocation::CreateFromArgs(CompilerInvocation &Res,
   Success &= ParseCodeGenArgs(Res.getCodeGenOpts(), Args, DashX, Diags,
                               Res.getTargetOpts());
   ParseHeaderSearchArgs(Res.getHeaderSearchOpts(), Args);
-  if (DashX != IK_AST && DashX != IK_LLVM_IR) {
+  if (DashX == IK_AST || DashX == IK_LLVM_IR) {
+    // ObjCAAutoRefCount and Sanitize LangOpts are used to setup the
+    // PassManager in BackendUtil.cpp. They need to be initializd no matter
+    // what the input type is.
+    if (Args.hasArg(OPT_fobjc_arc))
+      Res.getLangOpts()->ObjCAutoRefCount = 1;
+    parseSanitizerKinds("-fsanitize=", Args.getAllArgValues(OPT_fsanitize_EQ),
+                        Diags, Res.getLangOpts()->Sanitize);
+  } else {
+    // Other LangOpts are only initialzed when the input is not AST or LLVM IR.
     ParseLangArgs(*Res.getLangOpts(), Args, DashX, Diags);
     if (Res.getFrontendOpts().ProgramAction == frontend::RewriteObjC)
       Res.getLangOpts()->ObjCExceptions = 1;