[DXC] Add -metal flag to DXC driver

This adds a flag to the DXC driver to enable calling the metal shader
converter if it is available to convert the final shader output for
metal.

Author: llvm-beanz

clang/include/clang/Driver/Action.h

@@ -75,9 +75,10 @@ class Action {
     LinkerWrapperJobClass,
     StaticLibJobClass,
     BinaryAnalyzeJobClass,
+    BinaryTranslatorJobClass,
 
     JobClassFirst = PreprocessJobClass,
-    JobClassLast = BinaryAnalyzeJobClass
+    JobClassLast = BinaryTranslatorJobClass
   };
 
   // The offloading kind determines if this action is binded to a particular
@@ -675,6 +676,17 @@ class BinaryAnalyzeJobAction : public JobAction {
   }
 };
 
+class BinaryTranslatorJobAction : public JobAction {
+  void anchor() override;
+
+public:
+  BinaryTranslatorJobAction(Action *Input, types::ID Type);
+
+  static bool classof(const Action *A) {
+    return A->getKind() == BinaryTranslatorJobClass;
+  }
+};
+
 } // namespace driver
 } // namespace clang
 

clang/include/clang/Driver/Options.td

@@ -9085,6 +9085,7 @@ def : Option<["/", "-"], "Qembed_debug", KIND_FLAG>, Group<dxc_Group>,
   HelpText<"Embed PDB in shader container (ignored)">;
 def spirv : DXCFlag<"spirv">,
   HelpText<"Generate SPIR-V code">;
+def metal : DXCFlag<"metal">, HelpText<"Generate Metal library">;
 def fspv_target_env_EQ : Joined<["-"], "fspv-target-env=">, Group<dxc_Group>,
   HelpText<"Specify the target environment">,
   Values<"vulkan1.2, vulkan1.3">;

clang/lib/Driver/Action.cpp

@@ -50,6 +50,8 @@ const char *Action::getClassName(ActionClass AC) {
     return "static-lib-linker";
   case BinaryAnalyzeJobClass:
     return "binary-analyzer";
+  case BinaryTranslatorJobClass:
+    return "binary-translator";
   }
 
   llvm_unreachable("invalid class");
@@ -459,3 +461,9 @@ void BinaryAnalyzeJobAction::anchor() {}
 
 BinaryAnalyzeJobAction::BinaryAnalyzeJobAction(Action *Input, types::ID Type)
     : JobAction(BinaryAnalyzeJobClass, Input, Type) {}
+
+void BinaryTranslatorJobAction::anchor() {}
+
+BinaryTranslatorJobAction::BinaryTranslatorJobAction(Action *Input,
+                                                     types::ID Type)
+    : JobAction(BinaryTranslatorJobClass, Input, Type) {}

clang/lib/Driver/Driver.cpp

@@ -4672,6 +4672,16 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
       Actions.push_back(C.MakeAction<BinaryAnalyzeJobAction>(
           LastAction, types::TY_DX_CONTAINER));
     }
+    if (Args.getLastArg(options::OPT_metal)) {
+      Action *LastAction = Actions.back();
+      // Metal shader converter runs on DXIL containers, which can either be
+      // validated (in which case they are TY_DX_CONTAINER), or unvalidated
+      // (TY_OBJECT).
+      if (LastAction->getType() == types::TY_DX_CONTAINER ||
+          LastAction->getType() == types::TY_Object)
+        Actions.push_back(C.MakeAction<BinaryTranslatorJobAction>(
+            LastAction, types::TY_DX_CONTAINER));
+    }
   }
 
   // Claim ignored clang-cl options.

clang/lib/Driver/ToolChain.cpp

@@ -639,6 +639,7 @@ Tool *ToolChain::getTool(Action::ActionClass AC) const {
   case Action::DsymutilJobClass:
   case Action::VerifyDebugInfoJobClass:
   case Action::BinaryAnalyzeJobClass:
+  case Action::BinaryTranslatorJobClass:
     llvm_unreachable("Invalid tool kind.");
 
   case Action::CompileJobClass:

clang/lib/Driver/ToolChains/HLSL.cpp

@@ -198,6 +198,22 @@ void tools::hlsl::Validator::ConstructJob(Compilation &C, const JobAction &JA,
                                          Exec, CmdArgs, Inputs, Input));
 }
 
+void tools::hlsl::MetalConverter::ConstructJob(
+    Compilation &C, const JobAction &JA, const InputInfo &Output,
+    const InputInfoList &Inputs, const ArgList &Args,
+    const char *LinkingOutput) const {
+  std::string MSCPath = getToolChain().GetProgramPath("metal-shaderconverter");
+  ArgStringList CmdArgs;
+  const InputInfo &Input = Inputs[0];
+  CmdArgs.push_back(Input.getFilename());
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Input.getFilename());
+
+  const char *Exec = Args.MakeArgString(MSCPath);
+  C.addCommand(std::make_unique<Command>(JA, *this, ResponseFileSupport::None(),
+                                         Exec, CmdArgs, Inputs, Input));
+}
+
 /// DirectX Toolchain
 HLSLToolChain::HLSLToolChain(const Driver &D, const llvm::Triple &Triple,
                              const ArgList &Args)
@@ -214,6 +230,10 @@ Tool *clang::driver::toolchains::HLSLToolChain::getTool(
     if (!Validator)
       Validator.reset(new tools::hlsl::Validator(*this));
     return Validator.get();
+  case Action::BinaryTranslatorJobClass:
+    if (!MetalConverter)
+      MetalConverter.reset(new tools::hlsl::MetalConverter(*this));
+    return MetalConverter.get();
   default:
     return ToolChain::getTool(AC);
   }

clang/lib/Driver/ToolChains/HLSL.h

@@ -29,6 +29,19 @@ class LLVM_LIBRARY_VISIBILITY Validator : public Tool {
                     const llvm::opt::ArgList &TCArgs,
                     const char *LinkingOutput) const override;
 };
+
+class LLVM_LIBRARY_VISIBILITY MetalConverter : public Tool {
+public:
+  MetalConverter(const ToolChain &TC)
+      : Tool("hlsl::MetalConverter", "metal-shaderconverter", TC) {}
+
+  bool hasIntegratedCPP() const override { return false; }
+
+  void ConstructJob(Compilation &C, const JobAction &JA,
+                    const InputInfo &Output, const InputInfoList &Inputs,
+                    const llvm::opt::ArgList &TCArgs,
+                    const char *LinkingOutput) const override;
+};
 } // namespace hlsl
 } // namespace tools
 
@@ -57,6 +70,7 @@ class LLVM_LIBRARY_VISIBILITY HLSLToolChain : public ToolChain {
 
 private:
   mutable std::unique_ptr<tools::hlsl::Validator> Validator;
+  mutable std::unique_ptr<tools::hlsl::MetalConverter> MetalConverter;
 };
 
 } // end namespace toolchains

clang/test/Driver/HLSL/metal-converter.hlsl

@@ -0,0 +1,14 @@
+// RUN: %clang_dxc -T cs_6_0 %s -metal -Fo tmp.mtl -### 2>&1 | FileCheck %s
+// RUN: %clang_dxc -T cs_6_0 %s -metal -Vd -Fo tmp.mtl -### 2>&1 | FileCheck %s
+// CHECK: "{{.*}}metal-shaderconverter{{(.exe)?}}" "tmp.mtl" "-o" "tmp.mtl"
+
+// RUN: %clang_dxc -T cs_6_0 %s -metal -### 2>&1 | FileCheck --check-prefix=NO_MTL %s
+// NO_MTL-NOT: metal-shaderconverter
+
+RWBuffer<float4> In : register(u0, space0);
+RWBuffer<float4> Out : register(u1, space4);
+
+[numthreads(1,1,1)]
+void main(uint GI : SV_GroupIndex) {
+  Out[GI] = In[GI] * In[GI];
+}