use-map.h

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// Copyright 2023 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef V8_COMPILER_TURBOSHAFT_USE_MAP_H_
#define V8_COMPILER_TURBOSHAFT_USE_MAP_H_
 
#include "src/compiler/turboshaft/sidetable.h"
 
namespace v8::internal::compiler::turboshaft {
 
typedef bool (*FunctionType)(const Operation& op, Zone* zone);
 
// UseMap computes uses of all operations of the given turboshaft graph. It
// provides a mapping from `OpIndex` to its `uses`.
class UseMap {
  struct PerOperationUses {
    // We encode offsets as follows:
    // offset < 0: -offset-1 indexes into {saturated_uses_}.
    // offset = 0: definition not visited yet.
    // offset > 0: offset indexes into {uses_}.
    int32_t offset = 0;
    uint32_t count = 0;
  };
 
 public:
  UseMap(const Graph& graph, Zone* zone, FunctionType filter);
 
  UseMap(const Graph& graph, Zone* zone)
      : UseMap(graph, zone,
               [](const Operation& op, Zone* zone) { return false; }) {}
 
  base::Vector<const OpIndex> uses(OpIndex index) const;
 
 private:
  void AddUse(const Graph* graph, OpIndex node, OpIndex use);
 
  FixedOpIndexSidetable<PerOperationUses> table_;
  ZoneVector<OpIndex> uses_;
  ZoneVector<ZoneVector<OpIndex>> saturated_uses_;
};
 
// SimdUseMap computes uses of SIMD operations of the given turboshaft graph and
// skip other operations.
class SimdUseMap : public UseMap, public NON_EXPORTED_BASE(ZoneObject) {
 public:
  SimdUseMap(const Graph& graph, Zone* zone)
      : UseMap(graph, zone, [](const Operation& op, Zone* zone) {
          if (op.outputs_rep().size() == 1 &&
              op.outputs_rep()[0] == RegisterRepresentation::Simd128()) {
            return false;
          }
 
          ZoneVector<MaybeRegisterRepresentation> storage(zone);
          for (auto rep : op.inputs_rep(storage)) {
            if (rep == MaybeRegisterRepresentation::Simd128()) return false;
          }
          return true;
        }) {}
};
 
}  // namespace v8::internal::compiler::turboshaft
 
#endif  // V8_COMPILER_TURBOSHAFT_USE_MAP_H_