[HLSL] add -fcgl option flag.

[python3kgae]

Summary

fcgl option will make compilation stop after clang codeGen and output the llvm ir.
It is added to check clang codeGen output for HLSL.

It will be translated into -S -emit-llvm and -disable-llvm-passes.

[aaron.ballman]

clang/include/clang/Driver/Options.td

6761

Any particular reason for this name? Naively, I have no idea what this does or how it relates to code generation.

6762

clang/unittests/Driver/ToolChainTest.cpp

613 ↗

(On Diff #427204)

Any reason not to use the typical lit tests for this? It seems like you should be able to add a Driver test that does -### and looks for the expected pass-down flags. And then you can add a -cc1 test to ensure that the -fcgl flag isn't supported there.

[beanz]

clang/include/clang/Driver/Options.td

6761

I have no idea what this name is short for… code gen language?… likeness?… lobotomy?…

We have this flag in DXC, and it is a useful shorthand.

Don’t know if @python3kgae or @pow2clk know what the actual abbreviation is.

6762

This really has nothing to do with DXIL as a target, and will apply to any HLSL target out of clang. A more accurate description might be that it disables all optimization and code generation passes.

[aaron.ballman]

clang/include/clang/Driver/Options.td

6761

Can we pick a more descriptive name, or would that make portability too much of a challenge? Could we have a more descriptive name and then have -fcgl be an alias for it, or is that overkill because this is a rarely-used option?

[python3kgae]

clang/include/clang/Driver/Options.td

6761

Sure. I'll add a more descriptive name and alias fcgl to it.

It is something like frontend codeGen listing if I remember correctly.

clang/unittests/Driver/ToolChainTest.cpp

613 ↗

(On Diff #427204)

I'll use -### to add a lit test.

[python3kgae]

Add emit_pristine_llvm to make fcgl easier to understand.
Also change unit test to lib test.

[aaron.ballman]

LGTM aside from a tiny nit.

clang/include/clang/Driver/Options.td

6764–6765

Aliases typically skip their help text.

[python3kgae]

Remove HelpText for alias option.

[aaron.ballman]

LGTM!

clang/include/clang/Driver/Options.td

 def _SLASH_ZW : CLJoined<"ZW">;
 
 //===----------------------------------------------------------------------===//
 // clang-dxc Options
 //===----------------------------------------------------------------------===//
 
 def dxc_Group : OptionGroup<"<clang-dxc options>">, Flags<[DXCOption]>,
   HelpText<"dxc compatibility options">;
+class DXCFlag<string name> : Option<["/", "-"], name, KIND_FLAG>,
+  Group<dxc_Group>, Flags<[DXCOption, NoXarchOption]>;
 class DXCJoinedOrSeparate<string name> : Option<["/", "-"], name,
   KIND_JOINED_OR_SEPARATE>, Group<dxc_Group>, Flags<[DXCOption, NoXarchOption]>;
 
 def dxc_help : Option<["/", "-", "--"], "help", KIND_JOINED>,
   Group<dxc_Group>, Flags<[DXCOption, NoXarchOption]>, Alias<help>,
   HelpText<"Display available options">;
 def Fo : DXCJoinedOrSeparate<"Fo">, Alias<o>,
   HelpText<"Output object file">;
 def dxil_validator_version : Option<["/", "-"], "validator-version", KIND_SEPARATE>,
   Group<dxc_Group>, Flags<[DXCOption, NoXarchOption, CC1Option, HelpHidden]>,
   HelpText<"Override validator version for module. Format: <major.minor>;"
            "Default: DXIL.dll version or current internal version">,
   MarshallingInfoString<TargetOpts<"DxilValidatorVersion">>;
 def target_profile : DXCJoinedOrSeparate<"T">, MetaVarName<"<profile>">,
   HelpText<"Set target profile">,
   Values<"ps_6_0, ps_6_1, ps_6_2, ps_6_3, ps_6_4, ps_6_5, ps_6_6, ps_6_7,"
          "vs_6_0, vs_6_1, vs_6_2, vs_6_3, vs_6_4, vs_6_5, vs_6_6, vs_6_7,"
          "gs_6_0, gs_6_1, gs_6_2, gs_6_3, gs_6_4, gs_6_5, gs_6_6, gs_6_7,"
          "hs_6_0, hs_6_1, hs_6_2, hs_6_3, hs_6_4, hs_6_5, hs_6_6, hs_6_7,"
          "ds_6_0, ds_6_1, ds_6_2, ds_6_3, ds_6_4, ds_6_5, ds_6_6, ds_6_7,"
          "cs_6_0, cs_6_1, cs_6_2, cs_6_3, cs_6_4, cs_6_5, cs_6_6, cs_6_7,"
          "lib_6_3, lib_6_4, lib_6_5, lib_6_6, lib_6_7, lib_6_x,"
          "ms_6_5, ms_6_6, ms_6_7,"
          "as_6_5, as_6_6, as_6_7">;
+def emit_pristine_llvm : DXCFlag<"emit-pristine-llvm">,
+  HelpText<"Emit pristine LLVM IR from the frontend by not running any LLVM passes at all."
+           "Same as -S + -emit-llvm + -disable-llvm-passes.">;
+def fcgl : DXCFlag<"fcgl">, Alias<emit_pristine_llvm>;

clang/lib/Driver/ToolChains/Clang.cpp

if ((types::isOpenCL(InputType) ||
       !Args.hasArg(options::OPT_cl_no_stdinc)) {
     CmdArgs.push_back("-finclude-default-header");
     CmdArgs.push_back("-fdeclare-opencl-builtins");
   }
 }
 
 static void RenderHLSLOptions(const ArgList &Args, ArgStringList &CmdArgs,
                               types::ID InputType) {
-  const unsigned ForwardedArguments[] = {options::OPT_dxil_validator_version};
+  const unsigned ForwardedArguments[] = {options::OPT_dxil_validator_version,
+                                         options::OPT_S, options::OPT_emit_llvm,
+                                         options::OPT_disable_llvm_passes};
 
   for (const auto &Arg : ForwardedArguments)
     if (const auto *A = Args.getLastArg(Arg))
       A->renderAsInput(Args, CmdArgs);
 }
 
 static void RenderARCMigrateToolOptions(const Driver &D, const ArgList &Args,
                                         ArgStringList &CmdArgs) {

clang/lib/Driver/ToolChains/HLSL.cpp

HLSLToolChain::TranslateArgs(const DerivedArgList &Args, StringRef BoundArch,
 
   for (Arg *A : Args) {
     if (A->getOption().getID() == options::OPT_dxil_validator_version) {
       StringRef ValVerStr = A->getValue();
       std::string ErrorMsg;
       if (!isLegalValidatorVersion(ValVerStr, getDriver()))
         continue;
     }
+    if (A->getOption().getID() == options::OPT_emit_pristine_llvm) {
+      // Translate fcgl into -S -emit-llvm and -disable-llvm-passes.
+      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_S));
+      DAL->AddFlagArg(nullptr, Opts.getOption(options::OPT_emit_llvm));
+      DAL->AddFlagArg(nullptr,
+                      Opts.getOption(options::OPT_disable_llvm_passes));
+      A->claim();
+      continue;
+    }
     DAL->append(A);
   }
   // Add default validator version if not set.
   // TODO: remove this once read validator version from validator.
   if (!DAL->hasArg(options::OPT_dxil_validator_version)) {
     const StringRef DefaultValidatorVer = "1.7";
     DAL->AddSeparateArg(nullptr,
                         Opts.getOption(options::OPT_dxil_validator_version),
                         DefaultValidatorVer);
   }
   return DAL;
 }

clang/test/Driver/dxc_fcgl.hlsl

+// RUN: %clang_dxc -fcgl foo.hlsl -### %s 2>&1 | FileCheck %s
+
+// Make sure fcgl option flag which translated into "-S" "-emit-llvm" "-disable-llvm-passes".
+// CHECK:"-S" "-emit-llvm" "-disable-llvm-passes"
+