Add clang DirectX target support

[beanz]

Summary

This change adds a stub DirectX target for clang to enable targeting
dxil targets.

[pete]

All seems very reasonable to me.

clang/lib/Basic/CMakeLists.txt

add_clang_library(clangBasic
   TargetInfo.cpp
   Targets.cpp
   Targets/AArch64.cpp
   Targets/AMDGPU.cpp
   Targets/ARC.cpp
   Targets/ARM.cpp
   Targets/AVR.cpp
   Targets/BPF.cpp
+  Targets/DirectX.cpp
   Targets/Hexagon.cpp
   Targets/Lanai.cpp
   Targets/Le64.cpp
   Targets/M68k.cpp
   Targets/MSP430.cpp
   Targets/Mips.cpp
   Targets/NVPTX.cpp
   Targets/OSTargets.cpp

clang/lib/Basic/Targets.cpp

 #include "Targets.h"
 
 #include "Targets/AArch64.h"
 #include "Targets/AMDGPU.h"
 #include "Targets/ARC.h"
 #include "Targets/ARM.h"
 #include "Targets/AVR.h"
 #include "Targets/BPF.h"
+#include "Targets/DirectX.h"
 #include "Targets/Hexagon.h"
 #include "Targets/Lanai.h"
 #include "Targets/Le64.h"
 #include "Targets/M68k.h"
 #include "Targets/MSP430.h"
 #include "Targets/Mips.h"
 #include "Targets/NVPTX.h"
 #include "Targets/OSTargets.h"
switch (os) {
       case llvm::Triple::Emscripten:
         return new EmscriptenTargetInfo<WebAssembly64TargetInfo>(Triple, Opts);
       case llvm::Triple::UnknownOS:
         return new WebAssemblyOSTargetInfo<WebAssembly64TargetInfo>(Triple, Opts);
       default:
         return nullptr;
     }
 
+  case llvm::Triple::dxil:
+    return new DirectXTargetInfo(Triple,Opts);
   case llvm::Triple::renderscript32:
     return new LinuxTargetInfo<RenderScript32TargetInfo>(Triple, Opts);
   case llvm::Triple::renderscript64:
     return new LinuxTargetInfo<RenderScript64TargetInfo>(Triple, Opts);
 
   case llvm::Triple::ve:
     return new LinuxTargetInfo<VETargetInfo>(Triple, Opts);
   }

clang/lib/Basic/Targets/DirectX.h

+//===--- DirectX.h - Declare DirectX target feature support -----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares DXIL TargetInfo objects.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_BASIC_TARGETS_DIRECTX_H
+#define LLVM_CLANG_LIB_BASIC_TARGETS_DIRECTX_H
+#include "clang/Basic/TargetInfo.h"
+#include "clang/Basic/TargetOptions.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Support/Compiler.h"
+
+namespace clang {
+namespace targets {
+
+static const unsigned DirectXAddrSpaceMap[] = {
+    0, // Default
+    1, // opencl_global
+    3, // opencl_local
+    2, // opencl_constant
+    0, // opencl_private
+    4, // opencl_generic
+    5, // opencl_global_device
+    6, // opencl_global_host
+    0, // cuda_device
+    0, // cuda_constant
+    0, // cuda_shared
+    // SYCL address space values for this map are dummy
+    0, // sycl_global
+    0, // sycl_global_device
+    0, // sycl_global_host
+    0, // sycl_local
+    0, // sycl_private
+    0, // ptr32_sptr
+    0, // ptr32_uptr
+    0  // ptr64
+};
+
+class LLVM_LIBRARY_VISIBILITY DirectXTargetInfo : public TargetInfo {
+public:
+  DirectXTargetInfo(const llvm::Triple &Triple, const TargetOptions &)
+      : TargetInfo(Triple) {
+    TLSSupported = false;
+    VLASupported = false;
+    LongWidth = LongAlign = 64;
+    AddrSpaceMap = &DirectXAddrSpaceMap;
+    UseAddrSpaceMapMangling = true;
+    HasLegalHalfType = true;
+    HasFloat16 = true;
+    NoAsmVariants = true;
+    resetDataLayout("e-m:e-p:32:32-i1:32-i8:8-i16:16-i32:32-i64:64-f16:16-f32:"
+                    "32-f64:64-n8:16:32:64");
+  }
+
+  void getTargetDefines(const LangOptions &Opts,
+                        MacroBuilder &Builder) const override;
+
+  bool hasFeature(StringRef Feature) const override {
+    return Feature == "directx";
+  }
+
+  ArrayRef<Builtin::Info> getTargetBuiltins() const override { return None; }
+
+  const char *getClobbers() const override { return ""; }
+
+  ArrayRef<const char *> getGCCRegNames() const override { return None; }
+
+  bool validateAsmConstraint(const char *&Name,
+                             TargetInfo::ConstraintInfo &info) const override {
+    return true;
+  }
+
+  ArrayRef<TargetInfo::GCCRegAlias> getGCCRegAliases() const override {
+    return None;
+  }
+
+  BuiltinVaListKind getBuiltinVaListKind() const override {
+    return TargetInfo::VoidPtrBuiltinVaList;
+  }
+};
+
+} // namespace targets
+} // namespace clang
+
+#endif // LLVM_CLANG_LIB_BASIC_TARGETS_DIRECTX_H

clang/lib/Basic/Targets/DirectX.cpp

+//===--- DirectX.cpp - Implement DirectX target feature support -----------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements DirectX TargetInfo objects.
+//
+//===----------------------------------------------------------------------===//
+
+#include "DirectX.h"
+#include "Targets.h"
+
+using namespace clang;
+using namespace clang::targets;
+
+void DirectXTargetInfo::getTargetDefines(const LangOptions &Opts,
+                                         MacroBuilder &Builder) const {
+  DefineStd(Builder, "DIRECTX", Opts);
+}

clang/test/CodeGenHLSL/basic-target.c

+// RUN: %clang -target dxil-pc-shadermodel6.0-pixel -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -target dxil-pc-shadermodel6.0-vertex -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -target dxil-pc-shadermodel6.0-compute -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -target dxil-pc-shadermodel6.0-library -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -target dxil-pc-shadermodel6.0-hull -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -target dxil-pc-shadermodel6.0-domain -S -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang -target dxil-pc-shadermodel6.0-geometry -S -emit-llvm -o - %s | FileCheck %s
+
+// CHECK: target datalayout = "e-m:e-p:32:32-i1:32-i8:8-i16:16-i32:32-i64:64-f16:16-f32:32-f64:64-n8:16:32:64"
+// CHECK: target triple = "dxil-pc-shadermodel6.0-{{[a-z]+}}"

clang/test/CodeGenHLSL/lit.local.cfg

+config.suffixes = ['.c', '.hlsl']