[clang] [llvm] [HLSL][DXIL][SPIRV] Implementation of an abstraction for intrinsic selection of HLSL backends (PR #87171)

[Farzon Lotfi via cfe-commits]

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+
+//===----- CGHLSLUtils.h - Utility functions for HLSL CodeGen ---*- 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 Provides utility function for HLSL code generation.
+// It is used to abstract away implementation details of backends.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_CODEGEN_CGHLSLUTILS_H
+#define LLVM_CLANG_LIB_CODEGEN_CGHLSLUTILS_H
+
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/IntrinsicsDirectX.h"
+#include "llvm/IR/IntrinsicsSPIRV.h"
+
+// Define the function generator macro
+#define GENERATE_HLSL_INTRINSIC_FUNCTION(name)                                 \
+  static llvm::Intrinsic::ID get_hlsl_##name##_intrinsic(                      \
+      const llvm::Triple::ArchType Arch) {                                     \
+    switch (Arch) {                                                            \
+    case llvm::Triple::dxil:                                                   \
+      return llvm::Intrinsic::dx_##name;                                       \
+    case llvm::Triple::spirv:                                                  \
+      return llvm::Intrinsic::spv_##name;                                      \
+    default:                                                                   \
+      llvm_unreachable("Input semantic not supported by target");              \
+    }                                                                          \
+  }
+
+class CGHLSLUtils {
+public:
+  GENERATE_HLSL_INTRINSIC_FUNCTION(all)
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farzonl wrote:

Looks like the common way to specify  something belongs in CG via namespaces is to put it under `clang::CodgeGen`. So will make this an `HLSLUtils` namespace like so
`namespace clang::CodeGen::HLSLUtils {...}`

https://github.com/llvm/llvm-project/pull/87171