/*
 * Copyright 2016 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.
 */

#include "src/ir.h"

#include <cassert>
#include <cstddef>
#include <numeric>

#include "src/cast.h"

namespace {

const char* ExprTypeName[] = {
  "AtomicFence",
  "AtomicLoad",
  "AtomicRmw",
  "AtomicRmwCmpxchg",
  "AtomicStore",
  "AtomicNotify",
  "AtomicWait",
  "Binary",
  "Block",
  "Br",
  "BrIf",
  "BrTable",
  "Call",
  "CallIndirect",
  "CallRef",
  "Compare",
  "Const",
  "Convert",
  "Drop",
  "GlobalGet",
  "GlobalSet",
  "If",
  "Load",
  "LocalGet",
  "LocalSet",
  "LocalTee",
  "Loop",
  "MemoryCopy",
  "DataDrop",
  "MemoryFill",
  "MemoryGrow",
  "MemoryInit",
  "MemorySize",
  "Nop",
  "RefIsNull",
  "RefFunc",
  "RefNull",
  "Rethrow",
  "Return",
  "ReturnCall",
  "ReturnCallIndirect",
  "Select",
  "SimdLaneOp",
  "SimdLoadLane",
  "SimdStoreLane",
  "SimdShuffleOp",
  "LoadSplat",
  "LoadZero",
  "Store",
  "TableCopy",
  "ElemDrop",
  "TableInit",
  "TableGet",
  "TableGrow",
  "TableSize",
  "TableSet",
  "TableFill",
  "Ternary",
  "Throw",
  "Try",
  "Unary",
  "Unreachable",
};

}  // end of anonymous namespace

namespace wabt {

const char* GetExprTypeName(ExprType type) {
  static_assert(WABT_ENUM_COUNT(ExprType) == WABT_ARRAY_SIZE(ExprTypeName),
                "Malformed ExprTypeName array");
  return ExprTypeName[size_t(type)];
}

const char* GetExprTypeName(const Expr& expr) {
  return GetExprTypeName(expr.type());
}

bool FuncSignature::operator==(const FuncSignature& rhs) const {
  return param_types == rhs.param_types && result_types == rhs.result_types;
}

const Export* Module::GetExport(string_view name) const {
  Index index = export_bindings.FindIndex(name);
  if (index >= exports.size()) {
    return nullptr;
  }
  return exports[index];
}

Index Module::GetFuncIndex(const Var& var) const {
  return func_bindings.FindIndex(var);
}

Index Module::GetGlobalIndex(const Var& var) const {
  return global_bindings.FindIndex(var);
}

Index Module::GetTableIndex(const Var& var) const {
  return table_bindings.FindIndex(var);
}

Index Module::GetMemoryIndex(const Var& var) const {
  return memory_bindings.FindIndex(var);
}

Index Module::GetFuncTypeIndex(const Var& var) const {
  return type_bindings.FindIndex(var);
}

Index Module::GetTagIndex(const Var& var) const {
  return tag_bindings.FindIndex(var);
}

Index Module::GetDataSegmentIndex(const Var& var) const {
  return data_segment_bindings.FindIndex(var);
}

Index Module::GetElemSegmentIndex(const Var& var) const {
  return elem_segment_bindings.FindIndex(var);
}

bool Module::IsImport(ExternalKind kind, const Var& var) const {
  switch (kind) {
    case ExternalKind::Func:
      return GetFuncIndex(var) < num_func_imports;

    case ExternalKind::Global:
      return GetGlobalIndex(var) < num_global_imports;

    case ExternalKind::Memory:
      return GetMemoryIndex(var) < num_memory_imports;

    case ExternalKind::Table:
      return GetTableIndex(var) < num_table_imports;

    case ExternalKind::Tag:
      return GetTagIndex(var) < num_tag_imports;

    default:
      return false;
  }
}

void LocalTypes::Set(const TypeVector& types) {
  decls_.clear();
  if (types.empty()) {
    return;
  }

  Type type = types[0];
  Index count = 1;
  for (Index i = 1; i < types.size(); ++i) {
    if (types[i] != type) {
      decls_.emplace_back(type, count);
      type = types[i];
      count = 1;
    } else {
      ++count;
    }
  }
  decls_.emplace_back(type, count);
}

Index LocalTypes::size() const {
  return std::accumulate(
      decls_.begin(), decls_.end(), 0,
      [](Index sum, const Decl& decl) { return sum + decl.second; });
}

Type LocalTypes::operator[](Index i) const {
  Index count = 0;
  for (auto decl: decls_) {
    if (i < count + decl.second) {
      return decl.first;
    }
    count += decl.second;
  }
  assert(i < count);
  return Type::Any;
}

Type Func::GetLocalType(Index index) const {
  Index num_params = decl.GetNumParams();
  if (index < num_params) {
    return GetParamType(index);
  } else {
    index -= num_params;
    assert(index < local_types.size());
    return local_types[index];
  }
}

Type Func::GetLocalType(const Var& var) const {
  return GetLocalType(GetLocalIndex(var));
}

Index Func::GetLocalIndex(const Var& var) const {
  if (var.is_index()) {
    return var.index();
  }
  return bindings.FindIndex(var);
}

const Func* Module::GetFunc(const Var& var) const {
  return const_cast<Module*>(this)->GetFunc(var);
}

Func* Module::GetFunc(const Var& var) {
  Index index = func_bindings.FindIndex(var);
  if (index >= funcs.size()) {
    return nullptr;
  }
  return funcs[index];
}

const Global* Module::GetGlobal(const Var& var) const {
  return const_cast<Module*>(this)->GetGlobal(var);
}

Global* Module::GetGlobal(const Var& var) {
  Index index = global_bindings.FindIndex(var);
  if (index >= globals.size()) {
    return nullptr;
  }
  return globals[index];
}

const Table* Module::GetTable(const Var& var) const {
  return const_cast<Module*>(this)->GetTable(var);
}

Table* Module::GetTable(const Var& var) {
  Index index = table_bindings.FindIndex(var);
  if (index >= tables.size()) {
    return nullptr;
  }
  return tables[index];
}

const Memory* Module::GetMemory(const Var& var) const {
  return const_cast<Module*>(this)->GetMemory(var);
}

Memory* Module::GetMemory(const Var& var) {
  Index index = memory_bindings.FindIndex(var);
  if (index >= memories.size()) {
    return nullptr;
  }
  return memories[index];
}

Tag* Module::GetTag(const Var& var) const {
  Index index = GetTagIndex(var);
  if (index >= tags.size()) {
    return nullptr;
  }
  return tags[index];
}

const DataSegment* Module::GetDataSegment(const Var& var) const {
  return const_cast<Module*>(this)->GetDataSegment(var);
}

DataSegment* Module::GetDataSegment(const Var& var) {
  Index index = data_segment_bindings.FindIndex(var);
  if (index >= data_segments.size()) {
    return nullptr;
  }
  return data_segments[index];
}

const ElemSegment* Module::GetElemSegment(const Var& var) const {
  return const_cast<Module*>(this)->GetElemSegment(var);
}

ElemSegment* Module::GetElemSegment(const Var& var) {
  Index index = elem_segment_bindings.FindIndex(var);
  if (index >= elem_segments.size()) {
    return nullptr;
  }
  return elem_segments[index];
}

const FuncType* Module::GetFuncType(const Var& var) const {
  return const_cast<Module*>(this)->GetFuncType(var);
}

FuncType* Module::GetFuncType(const Var& var) {
  Index index = type_bindings.FindIndex(var);
  if (index >= types.size()) {
    return nullptr;
  }
  return dyn_cast<FuncType>(types[index]);
}

Index Module::GetFuncTypeIndex(const FuncSignature& sig) const {
  for (size_t i = 0; i < types.size(); ++i) {
    if (auto* func_type = dyn_cast<FuncType>(types[i])) {
      if (func_type->sig == sig) {
        return i;
      }
    }
  }
  return kInvalidIndex;
}

Index Module::GetFuncTypeIndex(const FuncDeclaration& decl) const {
  if (decl.has_func_type) {
    return GetFuncTypeIndex(decl.type_var);
  } else {
    return GetFuncTypeIndex(decl.sig);
  }
}

void Module::AppendField(std::unique_ptr<DataSegmentModuleField> field) {
  DataSegment& data_segment = field->data_segment;
  if (!data_segment.name.empty()) {
    data_segment_bindings.emplace(data_segment.name,
                                  Binding(field->loc, data_segments.size()));
  }
  data_segments.push_back(&data_segment);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<ElemSegmentModuleField> field) {
  ElemSegment& elem_segment = field->elem_segment;
  if (!elem_segment.name.empty()) {
    elem_segment_bindings.emplace(elem_segment.name,
                                  Binding(field->loc, elem_segments.size()));
  }
  elem_segments.push_back(&elem_segment);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<TagModuleField> field) {
  Tag& tag = field->tag;
  if (!tag.name.empty()) {
    tag_bindings.emplace(tag.name, Binding(field->loc, tags.size()));
  }
  tags.push_back(&tag);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<ExportModuleField> field) {
  // Exported names are allowed to be empty.
  Export& export_ = field->export_;
  export_bindings.emplace(export_.name, Binding(field->loc, exports.size()));
  exports.push_back(&export_);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<FuncModuleField> field) {
  Func& func = field->func;
  if (!func.name.empty()) {
    func_bindings.emplace(func.name, Binding(field->loc, funcs.size()));
  }
  funcs.push_back(&func);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<TypeModuleField> field) {
  TypeEntry& type = *field->type;
  if (!type.name.empty()) {
    type_bindings.emplace(type.name, Binding(field->loc, types.size()));
  }
  types.push_back(&type);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<GlobalModuleField> field) {
  Global& global = field->global;
  if (!global.name.empty()) {
    global_bindings.emplace(global.name, Binding(field->loc, globals.size()));
  }
  globals.push_back(&global);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<ImportModuleField> field) {
  Import* import = field->import.get();
  const std::string* name = nullptr;
  BindingHash* bindings = nullptr;
  Index index = kInvalidIndex;

  switch (import->kind()) {
    case ExternalKind::Func: {
      Func& func = cast<FuncImport>(import)->func;
      name = &func.name;
      bindings = &func_bindings;
      index = funcs.size();
      funcs.push_back(&func);
      ++num_func_imports;
      break;
    }

    case ExternalKind::Table: {
      Table& table = cast<TableImport>(import)->table;
      name = &table.name;
      bindings = &table_bindings;
      index = tables.size();
      tables.push_back(&table);
      ++num_table_imports;
      break;
    }

    case ExternalKind::Memory: {
      Memory& memory = cast<MemoryImport>(import)->memory;
      name = &memory.name;
      bindings = &memory_bindings;
      index = memories.size();
      memories.push_back(&memory);
      ++num_memory_imports;
      break;
    }

    case ExternalKind::Global: {
      Global& global = cast<GlobalImport>(import)->global;
      name = &global.name;
      bindings = &global_bindings;
      index = globals.size();
      globals.push_back(&global);
      ++num_global_imports;
      break;
    }

    case ExternalKind::Tag: {
      Tag& tag = cast<TagImport>(import)->tag;
      name = &tag.name;
      bindings = &tag_bindings;
      index = tags.size();
      tags.push_back(&tag);
      ++num_tag_imports;
      break;
    }
  }

  assert(name && bindings && index != kInvalidIndex);
  if (!name->empty()) {
    bindings->emplace(*name, Binding(field->loc, index));
  }
  imports.push_back(import);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<MemoryModuleField> field) {
  Memory& memory = field->memory;
  if (!memory.name.empty()) {
    memory_bindings.emplace(memory.name, Binding(field->loc, memories.size()));
  }
  memories.push_back(&memory);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<StartModuleField> field) {
  starts.push_back(&field->start);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<TableModuleField> field) {
  Table& table = field->table;
  if (!table.name.empty()) {
    table_bindings.emplace(table.name, Binding(field->loc, tables.size()));
  }
  tables.push_back(&table);
  fields.push_back(std::move(field));
}

void Module::AppendField(std::unique_ptr<ModuleField> field) {
  switch (field->type()) {
    case ModuleFieldType::Func:
      AppendField(cast<FuncModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Global:
      AppendField(cast<GlobalModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Import:
      AppendField(cast<ImportModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Export:
      AppendField(cast<ExportModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Type:
      AppendField(cast<TypeModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Table:
      AppendField(cast<TableModuleField>(std::move(field)));
      break;

    case ModuleFieldType::ElemSegment:
      AppendField(cast<ElemSegmentModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Memory:
      AppendField(cast<MemoryModuleField>(std::move(field)));
      break;

    case ModuleFieldType::DataSegment:
      AppendField(cast<DataSegmentModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Start:
      AppendField(cast<StartModuleField>(std::move(field)));
      break;

    case ModuleFieldType::Tag:
      AppendField(cast<TagModuleField>(std::move(field)));
      break;
  }
}

void Module::AppendFields(ModuleFieldList* fields) {
  while (!fields->empty())
    AppendField(std::unique_ptr<ModuleField>(fields->extract_front()));
}

const Module* Script::GetFirstModule() const {
  return const_cast<Script*>(this)->GetFirstModule();
}

Module* Script::GetFirstModule() {
  for (const std::unique_ptr<Command>& command : commands) {
    if (auto* module_command = dyn_cast<ModuleCommand>(command.get())) {
      return &module_command->module;
    }
  }
  return nullptr;
}

const Module* Script::GetModule(const Var& var) const {
  Index index = module_bindings.FindIndex(var);
  if (index >= commands.size()) {
    return nullptr;
  }
  auto* command = cast<ModuleCommand>(commands[index].get());
  return &command->module;
}

void MakeTypeBindingReverseMapping(
    size_t num_types,
    const BindingHash& bindings,
    std::vector<std::string>* out_reverse_mapping) {
  out_reverse_mapping->clear();
  out_reverse_mapping->resize(num_types);
  for (const auto& pair : bindings) {
    assert(static_cast<size_t>(pair.second.index) <
           out_reverse_mapping->size());
    (*out_reverse_mapping)[pair.second.index] = pair.first;
  }
}

Var::Var(Index index, const Location& loc)
    : loc(loc), type_(VarType::Index), index_(index) {}

Var::Var(string_view name, const Location& loc)
    : loc(loc), type_(VarType::Name), name_(name) {}

Var::Var(Var&& rhs) : Var(kInvalidIndex) {
  *this = std::move(rhs);
}

Var::Var(const Var& rhs) : Var(kInvalidIndex) {
  *this = rhs;
}

Var& Var::operator=(Var&& rhs) {
  loc = rhs.loc;
  if (rhs.is_index()) {
    set_index(rhs.index_);
  } else {
    set_name(rhs.name_);
  }
  return *this;
}

Var& Var::operator=(const Var& rhs) {
  loc = rhs.loc;
  if (rhs.is_index()) {
    set_index(rhs.index_);
  } else {
    set_name(rhs.name_);
  }
  return *this;
}

Var::~Var() {
  Destroy();
}

void Var::set_index(Index index) {
  Destroy();
  type_ = VarType::Index;
  index_ = index;
}

void Var::set_name(std::string&& name) {
  Destroy();
  type_ = VarType::Name;
  Construct(name_, std::move(name));
}

void Var::set_name(string_view name) {
  set_name(name.to_string());
}

void Var::Destroy() {
  if (is_name()) {
    Destruct(name_);
  }
}

uint8_t ElemSegment::GetFlags(const Module* module) const {
  uint8_t flags = 0;

  bool all_ref_func = elem_type == Type::FuncRef;

  switch (kind) {
    case SegmentKind::Active: {
      Index table_index = module->GetTableIndex(table_var);
      if (table_index != 0) {
        flags |= SegExplicitIndex;
      }
      break;
    }

    case SegmentKind::Passive:
      flags |= SegPassive;
      break;

    case SegmentKind::Declared:
      flags |= SegDeclared;
      break;
  }

  all_ref_func = all_ref_func &&
                 std::all_of(elem_exprs.begin(), elem_exprs.end(),
                             [](const ElemExpr& elem_expr) {
                               return elem_expr.kind == ElemExprKind::RefFunc;
                             });
  if (!all_ref_func) {
    flags |= SegUseElemExprs;
  }

  return flags;
}

uint8_t DataSegment::GetFlags(const Module* module) const {
  uint8_t flags = 0;

  if (kind == SegmentKind::Passive) {
    flags |= SegPassive;
  }

  Index memory_index = module->GetMemoryIndex(memory_var);
  if (memory_index != 0) {
    flags |= SegExplicitIndex;
  }

  return flags;
}


}  // namespace wabt
