SemanticSignaturePacking.h

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//===- SemanticSignaturePacking.h - HLSL signature packing helpers -------===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file This file declares helpers for packing HLSL semantic signatures.
///
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_FRONTEND_HLSL_SEMANTICSIGNATUREPACKING_H
#define LLVM_FRONTEND_HLSL_SEMANTICSIGNATUREPACKING_H
 
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Frontend/HLSL/SemanticSignatures.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Error.h"
#include "llvm/TargetParser/Triple.h"
 
namespace llvm::hlsl {
 
static constexpr unsigned MaxSignatureRows = 32;
static constexpr unsigned MaxSignatureCols = 4;
static constexpr unsigned MaxClipCullRows = 2;
static constexpr unsigned MaxGeometryStreams = 4;
 
/// Denotes the element that could not be packed and why.
class LLVM_ABI SignaturePackingError : public ErrorInfo<SignaturePackingError> {
public:
  enum ErrorKind {
    SignatureOverflow,
    SemanticIndexOutOfRange,
    ClipCullOverflow,
    ClipCullNotAdjacent,
    InvalidGeometryStream,
  };
 
  static char ID;
 
  SignaturePackingError(ErrorKind Kind, unsigned ElementIndex)
      : Kind(Kind), ElementIndex(ElementIndex) {}
 
  ErrorKind getErrorKind() const { return Kind; }
  unsigned getElementIndex() const { return ElementIndex; }
 
  void log(raw_ostream &OS) const override;
 
  std::error_code convertToErrorCode() const override {
    return llvm::inconvertibleErrorCode();
  }
 
private:
  ErrorKind Kind;
  unsigned ElementIndex;
};
 
/// Packs eligible signature elements into consecutive rows.
///
/// See llvm/docs/DirectX/SemanticSignatures.md#stacked-packing for details.
///
/// On failure, Elements is left partially packed: the elements preceding the
/// one reported by the returned SignaturePackingError keep the locations
/// they were assigned, while that element and the ones following it retain the
/// unallocated row and column sentinels.
LLVM_ABI Expected<unsigned>
packSignatureStacked(MutableArrayRef<SemanticSignatureElement> Elements,
                     Triple::EnvironmentType ShaderStage, IOType IOTy);
 
/// Packs eligible signature elements without moving previously placed
/// elements. Only StartRow and StartCol are modified.
///
/// See llvm/docs/DirectX/SemanticSignatures.md#prefix-stable-packing for
/// details.
///
/// Returns one past the highest allocated row, or zero if no elements were
/// allocated. For geometry outputs this is the maximum extent of any stream,
/// not the sum of their extents.
///
/// On failure, Elements is left partially packed: the elements preceding the
/// one reported by the returned SignaturePackingError keep the locations
/// they were assigned, while that element and the ones following it retain the
/// unallocated row and column sentinels.
LLVM_ABI Expected<unsigned>
packSignaturePrefixStable(MutableArrayRef<SemanticSignatureElement> Elements,
                          Triple::EnvironmentType ShaderStage, IOType IOTy,
                          bool UseNative16BitTypes);
 
/// Packs eligible signature elements at rows selected by semantic index.
///
/// See llvm/docs/DirectX/SemanticSignatures.md#indexed-packing for details.
///
/// Requires each eligible element to occupy exactly one row and have exactly
/// one semantic index. Semantic indices must be unique among eligible elements.
///
/// Returns one past the highest allocated row, or zero if no elements were
/// allocated. Gaps between semantic indices count towards this row extent.
///
/// On failure, Elements is left partially packed: the elements preceding the
/// one reported by the returned SignaturePackingError keep the locations
/// they were assigned, while that element and the ones following it retain the
/// unallocated row and column sentinels.
LLVM_ABI Expected<unsigned>
packSignatureIndexed(MutableArrayRef<SemanticSignatureElement> Elements,
                     Triple::EnvironmentType ShaderStage, IOType IOTy);
 
/// Packs eligible signature elements in an optimized order by reordering
/// elements into an optimal packing order and allowing clip/cull to share
/// compatible rows. Only StartRow and StartCol are modified.
///
/// See llvm/docs/DirectX/SemanticSignatures.md#optimized-packing for details.
///
/// Returns the number of allocated rows, or zero if no elements were
/// allocated. For geometry outputs this is the maximum extent of any stream,
/// not the sum of their extents.
///
/// On failure, Elements are left partially packed: the elements preceding the
/// one reported by the returned SignaturePackingError keep the locations
/// they were assigned, while that element and the ones following it retain the
/// unallocated row and column sentinels.
LLVM_ABI Expected<unsigned>
packSignatureOptimized(MutableArrayRef<SemanticSignatureElement> Elements,
                       Triple::EnvironmentType ShaderStage, IOType IOTy,
                       bool UseNative16BitTypes);
 
} // namespace llvm::hlsl
 
#endif // LLVM_FRONTEND_HLSL_SEMANTICSIGNATUREPACKING_H