CGHLSLRuntime.h

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//===----- 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::StringRef TyName,
                                   llvm::hlsl::ResourceClass RC,
                                   llvm::hlsl::ResourceKind RK,
                                   BufferResBinding &Binding);
  void addConstant(VarDecl *D, Buffer &CB);
  void addBufferDecls(const DeclContext *DC, Buffer &CB);
  llvm::SmallVector<Buffer> Buffers;
};
 
} // namespace CodeGen
} // namespace clang
 
#endif