[clang] [DirectX] Add DirectXTargetCodeGenInfo (PR #104856)

[Justin Bogner via cfe-commits]

================
@@ -0,0 +1,60 @@
+//===- DirectX.cpp
+//-----------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "ABIInfoImpl.h"
+#include "TargetInfo.h"
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace clang;
+using namespace clang::CodeGen;
+
+//===----------------------------------------------------------------------===//
+// Target codegen info implementation for DirectX.
+//===----------------------------------------------------------------------===//
+
+namespace {
+
+class DirectXTargetCodeGenInfo : public TargetCodeGenInfo {
+public:
+  DirectXTargetCodeGenInfo(CodeGen::CodeGenTypes &CGT)
+      : TargetCodeGenInfo(std::make_unique<DefaultABIInfo>(CGT)) {}
+
+  llvm::Type *getHLSLType(CodeGenModule &CGM, const Type *T) const override;
+};
+
+llvm::Type *DirectXTargetCodeGenInfo::getHLSLType(CodeGenModule &CGM,
+                                                  const Type *Ty) const {
+  llvm::LLVMContext &Ctx = CGM.getLLVMContext();
+  if (auto *BuiltinTy = dyn_cast<BuiltinType>(Ty)) {
+    switch (BuiltinTy->getKind()) {
+    case BuiltinType::HLSLResource: {
+      // FIXME: translate __hlsl_resource_t to target("dx.TypedBuffer", i32, 1,
+      // 0, 1) only for now (RWBuffer<int>); more work us needed to determine
+      // the target ext type and its parameters based on the handle type
+      // attributes (not yet implemented)
+      llvm::IntegerType *ElemType = llvm::IntegerType::getInt32Ty(Ctx);
----------------
bogner wrote:

Probably better to hard code this to `<4 x float>` rather than `i32` while we're just emitting a dummy type. That's the "default" type of `RWBuffer` and friends in HLSL source.

https://github.com/llvm/llvm-project/pull/104856