//===----- CGHLSLRuntime.h - Interface to HLSL Runtimes -----*- 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 provides an abstract class for HLSL code generation.  Concrete

// subclasses of this implement code generation for specific HLSL

// runtime libraries.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_LIB_CODEGEN_CGHLSLRUNTIME_H

#define LLVM_CLANG_LIB_CODEGEN_CGHLSLRUNTIME_H

#include "llvm/IR/IRBuilder.h"

#include "clang/Basic/HLSLRuntime.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/Frontend/HLSL/HLSLResource.h"

#include <optional>

#include <vector>

namespace llvm {

class GlobalVariable;

class Function;

class StructType;

} // namespace llvm

namespace clang {

class VarDecl;

class ParmVarDecl;

class HLSLBufferDecl;

class HLSLResourceBindingAttr;

class Type;

class DeclContext;

class FunctionDecl;

namespace CodeGen {

class CodeGenModule;

class CGHLSLRuntime {

public:

  struct BufferResBinding {

    // The ID like 2 in register(b2, space1).

    std::optional<unsigned> Reg;

    // The Space like 1 is register(b2, space1).

    // Default value is 0.

    unsigned Space;

    BufferResBinding(HLSLResourceBindingAttr *Attr);

  };

  struct Buffer {

    Buffer(const HLSLBufferDecl *D);

    llvm::StringRef Name;

    // IsCBuffer - Whether the buffer is a cbuffer (and not a tbuffer).

    bool IsCBuffer;

    BufferResBinding Binding;

    // Global variable and offset for each constant.

    std::vector<std::pair<llvm::GlobalVariable *, unsigned>> Constants;

    llvm::StructType *LayoutStruct = nullptr;

  };

protected:

  CodeGenModule &CGM;

  llvm::Value *emitInputSemantic(llvm::IRBuilder<> &B, const ParmVarDecl &D,

                                 llvm::Type *Ty);

public:

  CGHLSLRuntime(CodeGenModule &CGM) : CGM(CGM) {}

  virtual ~CGHLSLRuntime() {}

  void annotateHLSLResource(const VarDecl *D, llvm::GlobalVariable *GV);

  void generateGlobalCtorDtorCalls();

  void addBuffer(const HLSLBufferDecl *D);

  void finishCodeGen();

  void setHLSLEntryAttributes(const FunctionDecl *FD, llvm::Function *Fn);

  void emitEntryFunction(const FunctionDecl *FD, llvm::Function *Fn);

  void setHLSLFunctionAttributes(llvm::Function *, const FunctionDecl *);

private:

  void addBufferResourceAnnotation(llvm::GlobalVariable *GV,

                                   llvm::hlsl::ResourceClass RC,

                                   llvm::hlsl::ResourceKind RK, bool IsROV,

                                   llvm::hlsl::ElementType ET,

                                   BufferResBinding &Binding);

  void addConstant(VarDecl *D, Buffer &CB);

  void addBufferDecls(const DeclContext *DC, Buffer &CB);

  llvm::SmallVector<Buffer> Buffers;

};

} // namespace CodeGen

} // namespace clang

#endif