/*
 * Copyright 2019 WebAssembly Community Group participants
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef wasm_features_h
#define wasm_features_h

#include <stdint.h>
#include <string>

#include "compiler-support.h"
#include "support/utilities.h"

namespace wasm {

struct FeatureSet {
  enum Feature : uint32_t {
    // These features are intended to those documented in tool-conventions:
    // https://github.com/WebAssembly/tool-conventions/blob/main/Linking.md#target-features-section
    None = 0,
    Atomics = 1 << 0,
    MutableGlobals = 1 << 1,
    TruncSat = 1 << 2,
    SIMD = 1 << 3,
    BulkMemory = 1 << 4,
    SignExt = 1 << 5,
    ExceptionHandling = 1 << 6,
    TailCall = 1 << 7,
    ReferenceTypes = 1 << 8,
    Multivalue = 1 << 9,
    GC = 1 << 10,
    Memory64 = 1 << 11,
    RelaxedSIMD = 1 << 12,
    ExtendedConst = 1 << 13,
    Strings = 1 << 14,
    MultiMemory = 1 << 15,
    StackSwitching = 1 << 16,
    SharedEverything = 1 << 17,
    FP16 = 1 << 18,
    BulkMemoryOpt = 1 << 19, // Just the memory.copy and fill operations
    // This features is a no-op for compatibility. Having it in this list means
    // that we can automatically generate tool flags that set it, but otherwise
    // it does nothing. Binaryen always accepts LEB call-indirect encodings.
    CallIndirectOverlong = 1 << 20,
    CustomDescriptors = 1 << 21,
    RelaxedAtomics = 1 << 22,
    CustomPageSizes = 1 << 23,
    Multibyte = 1 << 24,
    MVP = None,
    // Keep in sync with llvm default features:
    // https://github.com/llvm/llvm-project/blob/c7576cb89d6c95f03968076e902d3adfd1996577/clang/lib/Basic/Targets/WebAssembly.cpp#L150-L153
    Default = SignExt | MutableGlobals,
    All = (1 << 25) - 1,
  };

  static std::string toString(Feature f) {
    switch (f) {
      case Atomics:
        return "threads";
      case MutableGlobals:
        return "mutable-globals";
      case TruncSat:
        return "nontrapping-float-to-int";
      case SIMD:
        return "simd";
      case BulkMemory:
        return "bulk-memory";
      case SignExt:
        return "sign-ext";
      case ExceptionHandling:
        return "exception-handling";
      case TailCall:
        return "tail-call";
      case ReferenceTypes:
        return "reference-types";
      case Multivalue:
        return "multivalue";
      case GC:
        return "gc";
      case Memory64:
        return "memory64";
      case RelaxedSIMD:
        return "relaxed-simd";
      case ExtendedConst:
        return "extended-const";
      case Strings:
        return "strings";
      case MultiMemory:
        return "multimemory";
      case StackSwitching:
        return "stack-switching";
      case SharedEverything:
        return "shared-everything";
      case FP16:
        return "fp16";
      case BulkMemoryOpt:
        return "bulk-memory-opt";
      case CallIndirectOverlong:
        return "call-indirect-overlong";
      case CustomDescriptors:
        return "custom-descriptors";
      case RelaxedAtomics:
        return "relaxed-atomics";
      case CustomPageSizes:
        return "custom-page-sizes";
      case Multibyte:
        return "multibyte";
      case MVP:
      case Default:
      case All:
        break;
    }
    WASM_UNREACHABLE("unexpected feature");
  }

  std::string toString() const {
    std::string ret;
    uint32_t x = 1;
    while (x & Feature::All) {
      if (features & x) {
        if (!ret.empty()) {
          ret += ", ";
        }
        ret += toString(Feature(x));
      }
      x <<= 1;
    }
    return ret;
  }

  FeatureSet() : features(None) {}
  FeatureSet(uint32_t features) : features(features) {}
  operator uint32_t() const { return features; }

  bool isMVP() const { return features == MVP; }
  bool has(FeatureSet f) const { return (features & f) == f.features; }
  bool hasAtomics() const { return (features & Atomics) != 0; }
  bool hasMutableGlobals() const { return (features & MutableGlobals) != 0; }
  bool hasTruncSat() const { return (features & TruncSat) != 0; }
  bool hasSIMD() const { return (features & SIMD) != 0; }
  bool hasBulkMemory() const { return (features & BulkMemory) != 0; }
  bool hasSignExt() const { return (features & SignExt) != 0; }
  bool hasExceptionHandling() const {
    return (features & ExceptionHandling) != 0;
  }
  bool hasTailCall() const { return (features & TailCall) != 0; }
  bool hasReferenceTypes() const { return (features & ReferenceTypes) != 0; }
  bool hasMultivalue() const { return (features & Multivalue) != 0; }
  bool hasGC() const { return (features & GC) != 0; }
  bool hasMemory64() const { return (features & Memory64) != 0; }
  bool hasRelaxedSIMD() const { return (features & RelaxedSIMD) != 0; }
  bool hasExtendedConst() const { return (features & ExtendedConst) != 0; }
  bool hasStrings() const { return (features & Strings) != 0; }
  bool hasMultiMemory() const { return (features & MultiMemory) != 0; }
  bool hasStackSwitching() const { return (features & StackSwitching) != 0; }
  bool hasSharedEverything() const {
    return (features & SharedEverything) != 0;
  }
  bool hasFP16() const { return (features & FP16) != 0; }
  bool hasBulkMemoryOpt() const {
    bool has = (features & BulkMemoryOpt) != 0;
    assert(has || !hasBulkMemory());
    return has;
  }
  bool hasCustomDescriptors() const {
    return (features & CustomDescriptors) != 0;
  }
  bool hasRelaxedAtomics() const { return (features & RelaxedAtomics) != 0; }
  bool hasCustomPageSizes() const { return (features & CustomPageSizes) != 0; }
  bool hasMultibyte() const { return (features & Multibyte) != 0; }
  bool hasAll() const { return (features & All) != 0; }

  void set(FeatureSet f, bool v = true) {
    features = v ? (features | f) : (features & ~f);
  }
  void setAtomics(bool v = true) { set(Atomics, v); }
  void setMutableGlobals(bool v = true) { set(MutableGlobals, v); }
  void setTruncSat(bool v = true) { set(TruncSat, v); }
  void setSIMD(bool v = true) { set(SIMD, v); }
  void setBulkMemory(bool v = true) { set(BulkMemory, v); }
  void setSignExt(bool v = true) { set(SignExt, v); }
  void setExceptionHandling(bool v = true) { set(ExceptionHandling, v); }
  void setTailCall(bool v = true) { set(TailCall, v); }
  void setReferenceTypes(bool v = true) { set(ReferenceTypes, v); }
  void setMultivalue(bool v = true) { set(Multivalue, v); }
  void setGC(bool v = true) { set(GC, v); }
  void setMemory64(bool v = true) { set(Memory64, v); }
  void setRelaxedSIMD(bool v = true) { set(RelaxedSIMD, v); }
  void setExtendedConst(bool v = true) { set(ExtendedConst, v); }
  void setStrings(bool v = true) { set(Strings, v); }
  void setMultiMemory(bool v = true) { set(MultiMemory, v); }
  void setStackSwitching(bool v = true) { set(StackSwitching, v); }
  void setSharedEverything(bool v = true) { set(SharedEverything, v); }
  void setFP16(bool v = true) { set(FP16, v); }
  void setBulkMemoryOpt(bool v = true) { set(BulkMemoryOpt, v); }
  void setCustomDescriptors(bool v = true) { set(CustomDescriptors, v); }
  void setRelaxedAtomics(bool v = true) { set(RelaxedAtomics, v); }
  void setMultibyte(bool v = true) { set(Multibyte, v); }
  void setMVP() { features = MVP; }
  void setAll() { features = All; }

  void enable(const FeatureSet& other) { features |= other.features; }
  void disable(const FeatureSet& other) { features &= ~other.features; }

  template<typename F> void iterFeatures(F f) const {
    for (uint32_t feature = MVP + 1; feature < All; feature <<= 1) {
      if (has(feature)) {
        f(static_cast<Feature>(feature));
      }
    }
  }

  bool isSubsetOf(const FeatureSet& other) const {
    return !(features & ~other.features);
  }

  bool operator==(const FeatureSet& other) const {
    return isSubsetOf(other) && other.isSubsetOf(*this);
  }

  bool operator!=(const FeatureSet& other) const { return !(*this == other); }

  FeatureSet& operator|=(const FeatureSet& other) {
    features |= other.features;
    return *this;
  }

  FeatureSet operator-(const FeatureSet& other) const {
    return features & ~other.features;
  }
  FeatureSet operator-(Feature other) const {
    return *this - FeatureSet(other);
  }

  uint32_t features;
};

} // namespace wasm

#endif // wasm_features_h