HLSLResource.h

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//===- HLSLResource.h - Routines for HLSL resources and bindings ----------===//
//
// 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 shared routines to help analyze HLSL resources and
// theirs bindings during Sema and CodeGen.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_AST_HLSLRESOURCE_H
#define LLVM_CLANG_AST_HLSLRESOURCE_H
 
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/AST/DeclBase.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Support/Compiler.h"
#include "llvm/Frontend/HLSL/HLSLResource.h"
#include "llvm/Support/raw_ostream.h"
 
namespace clang {
 
class HLSLResourceBindingAttr;
 
namespace hlsl {
 
struct ResourceBindingAttrs {
  HLSLResourceBindingAttr *RegBinding;
  HLSLVkBindingAttr *VkBinding;
 
  ResourceBindingAttrs(const Decl *D) {
    RegBinding = D->getAttr<HLSLResourceBindingAttr>();
    bool IsSpirv = D->getASTContext().getTargetInfo().getTriple().isSPIRV();
    VkBinding = IsSpirv ? D->getAttr<HLSLVkBindingAttr>() : nullptr;
  }
 
  bool hasBinding() const { return RegBinding || VkBinding; }
  bool isExplicit() const {
    return (RegBinding && RegBinding->hasRegisterSlot()) || VkBinding;
  }
 
  unsigned getSlot() const {
    assert(isExplicit() && "no explicit binding");
    if (VkBinding)
      return VkBinding->getBinding();
    if (RegBinding && RegBinding->hasRegisterSlot())
      return RegBinding->getSlotNumber();
    llvm_unreachable("no explicit binding");
  }
 
  unsigned getSpace() const {
    if (VkBinding)
      return VkBinding->getSet();
    if (RegBinding)
      return RegBinding->getSpaceNumber();
    return 0;
  }
 
  bool hasImplicitOrderID() const {
    return RegBinding && RegBinding->hasImplicitBindingOrderID();
  }
 
  unsigned getImplicitOrderID() const {
    assert(hasImplicitOrderID());
    return RegBinding->getImplicitBindingOrderID();
  }
 
  void setImplicitOrderID(unsigned Value) const {
    assert(hasBinding() && !isExplicit() && !hasImplicitOrderID());
    RegBinding->setImplicitBindingOrderID(Value);
  }
  void setCounterImplicitOrderID(unsigned Value) const {
    assert(hasBinding() && !hasCounterImplicitOrderID());
    RegBinding->setImplicitCounterBindingOrderID(Value);
  }
 
  bool hasCounterImplicitOrderID() const {
    return RegBinding && RegBinding->hasImplicitCounterBindingOrderID();
  }
 
  unsigned getCounterImplicitOrderID() const {
    assert(hasCounterImplicitOrderID());
    return RegBinding->getImplicitCounterBindingOrderID();
  }
};
 
inline uint32_t getResourceDimensions(llvm::dxil::ResourceDimension Dim) {
  switch (Dim) {
  case llvm::dxil::ResourceDimension::Dim1D:
    return 1;
    break;
  case llvm::dxil::ResourceDimension::Dim2D:
    return 2;
    break;
  case llvm::dxil::ResourceDimension::Dim3D:
  case llvm::dxil::ResourceDimension::Cube:
    return 3;
    break;
  case llvm::dxil::ResourceDimension::Unknown:
    llvm_unreachable(
        "We cannot get the dimension of a resource with unknown dimension.");
  }
  llvm_unreachable("Unhandled llvm::dxil::ResourceDimension enum.");
}
 
// Returns true if sampling operations on a resource of this dimension take a
// texel-space offset operand.
inline bool hasResourceOffset(llvm::dxil::ResourceDimension Dim) {
  return Dim != llvm::dxil::ResourceDimension::Cube;
}
 
// Returns true if the second field of the record is a counter resource handle
inline bool hasCounterHandle(const CXXRecordDecl *RD) {
  if (RD->field_empty())
    return false;
  auto It = std::next(RD->field_begin());
  if (It == RD->field_end())
    return false;
  const FieldDecl *SecondField = *It;
  if (const auto *ResTy =
          SecondField->getType()->getAs<HLSLAttributedResourceType>()) {
    return ResTy->getAttrs().IsCounter;
  }
  return false;
}
 
// Helper class for building a name of a global resource variable that
// gets created for a resource embedded in a struct or class. This will
// also be used from CodeGen to build a name that matches the resource
// access with the corresponding declaration.
class EmbeddedResourceNameBuilder {
  llvm::SmallString<64> Name;
  llvm::SmallVector<unsigned> Offsets;
 
  inline static constexpr std::string_view BaseClassDelim = "::";
  inline static constexpr std::string_view FieldDelim = ".";
  inline static constexpr std::string_view ArrayIndexDelim = FieldDelim;
 
public:
  EmbeddedResourceNameBuilder(llvm::StringRef BaseName) : Name(BaseName) {}
  EmbeddedResourceNameBuilder() : Name("") {}
 
  void pushName(llvm::StringRef N) { pushName(N, FieldDelim); }
  void pushBaseName(llvm::StringRef N);
  void pushArrayIndex(uint64_t Index);
  void pushBaseNameHierarchy(CXXRecordDecl *DerivedRD, CXXRecordDecl *BaseRD);
 
  void pop() {
    assert(!Offsets.empty() && "no name to pop");
    Name.resize(Offsets.pop_back_val());
  }
 
  IdentifierInfo *getNameAsIdentifier(ASTContext &AST) const {
    return &AST.Idents.get(Name);
  }
 
  llvm::StringRef getName() const { return Name; }
 
private:
  void pushName(llvm::StringRef N, llvm::StringRef Delim);
};
 
} // namespace hlsl
 
} // namespace clang
 
#endif // LLVM_CLANG_AST_HLSLRESOURCE_H