ModRefSummary.hpp

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/*
 * Copyright 2022 Nico Reißmann <nico.reissmann@gmail.com>
 * Copyright 2025 Håvard Krogstie <krogstie.havard@gmail.com>
 * See COPYING for terms of redistribution.
 */
 
#ifndef JLM_LLVM_OPT_ALIAS_ANALYSES_MODREFSUMMARY_HPP
#define JLM_LLVM_OPT_ALIAS_ANALYSES_MODREFSUMMARY_HPP
 
#include <jlm/llvm/opt/alias-analyses/PointsToGraph.hpp>
#include <jlm/rvsdg/gamma.hpp>
#include <jlm/rvsdg/theta.hpp>
#include <jlm/util/HashSet.hpp>
 
#include <type_traits>
#include <unordered_map>
 
namespace jlm::llvm::aa
{
 
enum ModRefEffect : uint8_t
{
  // The set has no effect on the memory node
  NoEffect = 0,
 
  // The set represents possibly reading from the memory
  RefOnly = 0b1,
 
  // The set represents possibly storing to the memory
  ModOnly = 0b10,
 
  // The set represents both reading and writing to the memory
  ModRef = 0b11
};
 
[[nodiscard]] inline bool
mayEffectReference(ModRefEffect effect)
{
  // Bitwise AND checks for both RefOnly and ModRef
  return effect & ModRefEffect::RefOnly;
}
 
[[nodiscard]] inline bool
mayEffectModify(ModRefEffect effect)
{
  // Bitwise AND checks for both ModOnly and ModRef
  return effect & ModRefEffect::ModOnly;
}
 
[[nodiscard]] inline ModRefEffect
operator|(ModRefEffect a, ModRefEffect b)
{
  return static_cast<ModRefEffect>(
      static_cast<std::underlying_type_t<ModRefEffect>>(a)
      | static_cast<std::underlying_type_t<ModRefEffect>>(b));
}
 
inline ModRefEffect &
operator|=(ModRefEffect & a, ModRefEffect b)
{
  return a = (a | b);
}
 
[[nodiscard]] inline bool
isEffectSubset(ModRefEffect subset, ModRefEffect superset)
{
  return (subset | superset) == superset;
}
 
class ModRefSet
{
public:
  [[nodiscard]] const std::unordered_map<PointsToGraph::NodeIndex, ModRefEffect> &
  getModRefNodes() const
  {
    return modRefNodes_;
  }
 
protected:
  // Prevent users of the ModRefSummary base class from accidentally copying sets by value,
  // or constructing empty ModRefSets. Instances should always be summarizer-specific subclasses.
  ModRefSet() = default;
  ModRefSet(const ModRefSet & other) = default;
  ModRefSet(ModRefSet && other) = default;
  ModRefSet &
  operator=(const ModRefSet & other) = default;
  ModRefSet &
  operator=(ModRefSet && other) = default;
 
  std::unordered_map<PointsToGraph::NodeIndex, ModRefEffect> modRefNodes_;
};
 
class ModRefSummary
{
public:
  virtual ~ModRefSummary() noexcept = default;
 
  [[nodiscard]] virtual const PointsToGraph &
  GetPointsToGraph() const noexcept = 0;
 
  [[nodiscard]] virtual const ModRefSet &
  GetSimpleNodeModRef(const rvsdg::SimpleNode & node) const = 0;
 
  [[nodiscard]] virtual const ModRefSet &
  GetGammaEntryModRef(const rvsdg::GammaNode & gamma) const = 0;
 
  [[nodiscard]] virtual const ModRefSet &
  GetGammaExitModRef(const rvsdg::GammaNode & gamma) const = 0;
 
  [[nodiscard]] virtual const ModRefSet &
  GetThetaModRef(const rvsdg::ThetaNode & theta) const = 0;
 
  [[nodiscard]] virtual const ModRefSet &
  GetLambdaEntryModRef(const rvsdg::LambdaNode & lambda) const = 0;
 
  [[nodiscard]] virtual const ModRefSet &
  GetLambdaExitModRef(const rvsdg::LambdaNode & lambda) const = 0;
};
 
}
 
#endif // JLM_LLVM_OPT_ALIAS_ANALYSES_MODREFSUMMARY_HPP