define hlsl-rootsig-ver for the clang/cc1/dxc drivers

- allow for fall-through from dxcoptions to cc1 options
- defined as a langopts and only allow when we are compiling HLSL

Author: inbelic

clang/include/clang/Basic/LangOptions.h

@@ -24,6 +24,7 @@
 #include "clang/Basic/Visibility.h"
 #include "llvm/ADT/FloatingPointMode.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/DXILABI.h"
 #include "llvm/TargetParser/Triple.h"
 #include <optional>
 #include <string>
@@ -623,6 +624,10 @@ class LangOptions : public LangOptionsBase {
   // implementation on real-world examples.
   std::string OpenACCMacroOverride;
 
+  /// The HLSL root signature version for dxil.
+  llvm::dxil::RootSignatureVersion HLSLRootSigVer =
+      llvm::dxil::RootSignatureVersion::rootsig_1_1;
+
   // Indicates if the wasm-opt binary must be ignored in the case of a
   // WebAssembly target.
   bool NoWasmOpt = false;

clang/include/clang/Driver/Options.td

@@ -9288,6 +9288,15 @@ def fcgl : DXCFlag<"fcgl">, Alias<emit_pristine_llvm>;
 def enable_16bit_types : DXCFlag<"enable-16bit-types">, Alias<fnative_half_type>,
   HelpText<"Enable 16-bit types and disable min precision types."
            "Available in HLSL 2018 and shader model 6.2.">;
+def hlsl_rootsig_ver :
+  Option<["-"], "hlsl-rootsig-ver", KIND_SEPARATE>,
+  Group<dxc_Group>,
+  Visibility<[ClangOption, CC1Option, DXCOption]>,
+  HelpText<"Root Signature Version">,
+  Values<"rootsig_1_0,rootsig_1_1">,
+  NormalizedValuesScope<"llvm::dxil::RootSignatureVersion">,
+  NormalizedValues<["rootsig_1_0", "rootsig_1_1"]>,
+  MarshallingInfoEnum<LangOpts<"HLSLRootSigVer">, "rootsig_1_1">;
 def hlsl_entrypoint : Option<["-"], "hlsl-entry", KIND_SEPARATE>,
                       Group<dxc_Group>,
                       Visibility<[ClangOption, CC1Option]>,

clang/lib/Driver/ToolChains/Clang.cpp

@@ -3834,7 +3834,8 @@ static void RenderHLSLOptions(const ArgList &Args, ArgStringList &CmdArgs,
                                          options::OPT_emit_obj,
                                          options::OPT_disable_llvm_passes,
                                          options::OPT_fnative_half_type,
-                                         options::OPT_hlsl_entrypoint};
+                                         options::OPT_hlsl_entrypoint,
+                                         options::OPT_hlsl_rootsig_ver};
   if (!types::isHLSL(InputType))
     return;
   for (const auto &Arg : ForwardedArguments)

clang/lib/Frontend/CompilerInvocation.cpp

@@ -636,6 +636,10 @@ static bool FixupInvocation(CompilerInvocation &Invocation,
     Diags.Report(diag::err_drv_argument_not_allowed_with)
         << "-hlsl-entry" << GetInputKindName(IK);
 
+  if (Args.hasArg(OPT_hlsl_rootsig_ver) && !LangOpts.HLSL)
+    Diags.Report(diag::err_drv_argument_not_allowed_with)
+        << "-hlsl-rootsig-ver" << GetInputKindName(IK);
+
   if (Args.hasArg(OPT_fgpu_allow_device_init) && !LangOpts.HIP)
     Diags.Report(diag::warn_ignored_hip_only_option)
         << Args.getLastArg(OPT_fgpu_allow_device_init)->getAsString(Args);