ark_ts2abc/es2panda/binder/scope.cpp

/**
 * Copyright (c) 2021 Huawei Device Co., Ltd.
 * 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 "scope.h"

#include <binder/declaration.h>
#include <util/helpers.h>
#include <binder/tsBinding.h>
#include <binder/variable.h>
#include <binder/variableFlags.h>
#include <ir/astNode.h>
#include <ir/expressions/identifier.h>
#include <ir/module/exportAllDeclaration.h>
#include <ir/module/exportNamedDeclaration.h>
#include <ir/module/exportSpecifier.h>
#include <ir/module/importDeclaration.h>
#include <macros.h>
#include <util/ustring.h>

#include <algorithm>
#include <sstream>

namespace panda::es2panda::binder {

VariableScope *Scope::EnclosingVariableScope()
{
    Scope *iter = this;

    while (iter) {
        if (iter->IsVariableScope()) {
            return iter->AsVariableScope();
        }

        iter = iter->Parent();
    }

    return nullptr;
}

Variable *Scope::FindLocal(const util::StringView &name, ResolveBindingOptions options) const
{
    if (options & ResolveBindingOptions::INTERFACES) {
        util::StringView interfaceNameView(binder::TSBinding::ToTSBinding(name));

        auto res = bindings_.find(interfaceNameView);
        if (res != bindings_.end()) {
            return res->second;
        }

        if (!(options & ResolveBindingOptions::BINDINGS)) {
            return nullptr;
        }
    }

    auto res = bindings_.find(name);
    if (res == bindings_.end()) {
        return nullptr;
    }

    return res->second;
}

ScopeFindResult Scope::Find(const util::StringView &name, ResolveBindingOptions options) const
{
    uint32_t level = 0;
    uint32_t lexLevel = 0;
    const auto *iter = this;

    while (iter != nullptr) {
        Variable *v = iter->FindLocal(name, options);

        if (v != nullptr) {
            return {name, const_cast<Scope *>(iter), level, lexLevel, v};
        }

        if (iter->IsVariableScope()) {
            level++;

            if (iter->AsVariableScope()->NeedLexEnv()) {
                lexLevel++;
            }
        }

        iter = iter->Parent();
    }

    return {name, nullptr, 0, 0, nullptr};
}

Decl *Scope::FindDecl(const util::StringView &name) const
{
    for (auto *it : decls_) {
        if (it->Name() == name) {
            return it;
        }
    }

    return nullptr;
}

std::tuple<Scope *, bool> Scope::IterateShadowedVariables(const util::StringView &name, const VariableVisitior &visitor)
{
    auto *iter = this;

    while (true) {
        auto *v = iter->FindLocal(name);

        if (v && visitor(v)) {
            return {iter, true};
        }

        if (iter->IsFunctionVariableScope()) {
            break;
        }

        iter = iter->Parent();
    }

    return {iter, false};
}

bool Scope::AddLocal(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                     [[maybe_unused]] ScriptExtension extension)
{
    VariableFlags flags = VariableFlags::NONE;
    switch (newDecl->Type()) {
        case DeclType::VAR: {
            auto [scope, shadowed] = IterateShadowedVariables(
                newDecl->Name(), [](const Variable *v) { return !v->HasFlag(VariableFlags::VAR); });

            if (shadowed) {
                return false;
            }

            VariableFlags varFlags = VariableFlags::HOIST_VAR | VariableFlags::LEXICAL_VAR;
            if (scope->IsGlobalScope()) {
                scope->Bindings().insert({newDecl->Name(), allocator->New<GlobalVariable>(newDecl, varFlags)});
            } else {
                scope->PropagateBinding<LocalVariable>(allocator, newDecl->Name(), newDecl, varFlags);
            }

            return true;
        }
        case DeclType::ENUM: {
            bindings_.insert({newDecl->Name(), allocator->New<EnumVariable>(newDecl, false)});
            return true;
        }
        case DeclType::ENUM_LITERAL: {
            bindings_.insert({newDecl->Name(), allocator->New<LocalVariable>(newDecl, VariableFlags::ENUM_LITERAL)});
            return true;
        }
        case DeclType::INTERFACE: {
            bindings_.insert({newDecl->Name(), allocator->New<LocalVariable>(newDecl, VariableFlags::INTERFACE)});
            return true;
        }
        case DeclType::FUNC: {
            flags = VariableFlags::HOIST;
            [[fallthrough]];
        }
        default: {
            if (currentVariable) {
                return false;
            }

            auto [_, shadowed] = IterateShadowedVariables(
                newDecl->Name(), [](const Variable *v) { return v->HasFlag(VariableFlags::LEXICAL_VAR); });
            (void)_;

            if (shadowed) {
                return false;
            }

            bindings_.insert({newDecl->Name(), allocator->New<LocalVariable>(newDecl, flags)});
            return true;
        }
    }
}

bool ParamScope::AddParam(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl, VariableFlags flags)
{
    ASSERT(newDecl->IsParameterDecl());

    if (currentVariable) {
        return false;
    }

    auto *param = allocator->New<LocalVariable>(newDecl, flags);

    params_.push_back(param);
    bindings_.insert({newDecl->Name(), param});
    return true;
}

std::tuple<ParameterDecl *, const ir::AstNode *> ParamScope::AddParamDecl(ArenaAllocator *allocator,
                                                                          const ir::AstNode *param)
{
    const auto [name, pattern] = util::Helpers::ParamName(allocator, param, params_.size());

    auto *decl = NewDecl<ParameterDecl>(allocator, name);

    if (!AddParam(allocator, FindLocal(name), decl, VariableFlags::VAR)) {
        return {decl, param};
    }

    if (!pattern) {
        return {decl, nullptr};
    }

    std::vector<const ir::Identifier *> bindings = util::Helpers::CollectBindingNames(param);

    for (const auto *binding : bindings) {
        auto *varDecl = NewDecl<VarDecl>(allocator, binding->Name());
        varDecl->BindNode(binding);

        if (FindLocal(varDecl->Name())) {
            return {decl, binding};
        }

        auto *paramVar = allocator->New<LocalVariable>(varDecl, VariableFlags::VAR);
        bindings_.insert({varDecl->Name(), paramVar});
    }

    return {decl, nullptr};
}

void FunctionParamScope::BindName(ArenaAllocator *allocator, util::StringView name)
{
    nameVar_ = AddDecl<ConstDecl, LocalVariable>(allocator, name, VariableFlags::INITIALIZED);
    functionScope_->Bindings().insert({name, nameVar_});
}

bool FunctionParamScope::AddBinding([[maybe_unused]] ArenaAllocator *allocator,
                                    [[maybe_unused]] Variable *currentVariable, [[maybe_unused]] Decl *newDecl,
                                    [[maybe_unused]] ScriptExtension extension)
{
    UNREACHABLE();
}

bool FunctionScope::AddBinding(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                               [[maybe_unused]] ScriptExtension extension)
{
    switch (newDecl->Type()) {
        case DeclType::VAR: {
            return AddVar<LocalVariable>(allocator, currentVariable, newDecl);
        }
        case DeclType::FUNC: {
            return AddFunction<LocalVariable>(allocator, currentVariable, newDecl, extension);
        }
        case DeclType::ENUM: {
            bindings_.insert({newDecl->Name(), allocator->New<EnumVariable>(newDecl, false)});
            return true;
        }
        case DeclType::ENUM_LITERAL: {
            return AddTSBinding<LocalVariable>(allocator, currentVariable, newDecl, VariableFlags::ENUM_LITERAL);
        }
        case DeclType::INTERFACE: {
            return AddTSBinding<LocalVariable>(allocator, currentVariable, newDecl, VariableFlags::INTERFACE);
        }
        default: {
            return AddLexical<LocalVariable>(allocator, currentVariable, newDecl);
        }
    }
}

bool GlobalScope::AddBinding(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                             [[maybe_unused]] ScriptExtension extension)
{
    switch (newDecl->Type()) {
        case DeclType::VAR: {
            return AddVar<GlobalVariable>(allocator, currentVariable, newDecl);
        }
        case DeclType::FUNC: {
            return AddFunction<GlobalVariable>(allocator, currentVariable, newDecl, extension);
        }
        case DeclType::ENUM: {
            bindings_.insert({newDecl->Name(), allocator->New<EnumVariable>(newDecl, false)});
            return true;
        }
        case DeclType::ENUM_LITERAL: {
            return AddTSBinding<LocalVariable>(allocator, currentVariable, newDecl, VariableFlags::ENUM_LITERAL);
        }
        case DeclType::INTERFACE: {
            return AddTSBinding<LocalVariable>(allocator, currentVariable, newDecl, VariableFlags::INTERFACE);
        }
        default: {
            return AddLexical<LocalVariable>(allocator, currentVariable, newDecl);
        }
    }

    return true;
}

// ModuleScope

bool ModuleScope::AddBinding(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                             [[maybe_unused]] ScriptExtension extension)
{
    switch (newDecl->Type()) {
        case DeclType::VAR: {
            return AddVar<LocalVariable>(allocator, currentVariable, newDecl);
        }
        case DeclType::FUNC: {
            return AddFunction<LocalVariable>(allocator, currentVariable, newDecl, extension);
        }
        case DeclType::ENUM: {
            bindings_.insert({newDecl->Name(), allocator->New<EnumVariable>(newDecl, false)});
            return true;
        }
        case DeclType::ENUM_LITERAL: {
            return AddTSBinding<LocalVariable>(allocator, currentVariable, newDecl, VariableFlags::ENUM_LITERAL);
        }
        case DeclType::INTERFACE: {
            return AddTSBinding<LocalVariable>(allocator, currentVariable, newDecl, VariableFlags::INTERFACE);
        }
        case DeclType::IMPORT: {
            return AddImport(allocator, currentVariable, newDecl);
        }
        case DeclType::EXPORT: {
            return true;
        }
        default: {
            return AddLexical<LocalVariable>(allocator, currentVariable, newDecl);
        }
    }
}

void ModuleScope::AddImportDecl(const ir::ImportDeclaration *importDecl, ImportDeclList &&decls)
{
    auto res = imports_.emplace_back(importDecl, decls);

    for (auto &decl : res.second) {
        decl->BindNode(importDecl);
    }
}

void ModuleScope::AddExportDecl(const ir::AstNode *exportDecl, ExportDecl *decl)
{
    decl->BindNode(exportDecl);

    ArenaVector<ExportDecl *> decls(allocator_->Adapter());
    decls.push_back(decl);

    AddExportDecl(exportDecl, std::move(decls));
}

void ModuleScope::AddExportDecl(const ir::AstNode *exportDecl, ExportDeclList &&decls)
{
    auto res = exports_.emplace_back(exportDecl, decls);

    for (auto &decl : res.second) {
        decl->BindNode(exportDecl);
    }
}

bool ModuleScope::AddImport(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl)
{
    if (currentVariable && currentVariable->Declaration()->Type() != DeclType::VAR) {
        return false;
    }

    if (newDecl->Node()->IsImportNamespaceSpecifier()) {
        bindings_.insert({newDecl->Name(), allocator->New<LocalVariable>(newDecl, VariableFlags::READONLY)});
    } else {
        auto *variable = allocator->New<ModuleVariable>(newDecl, VariableFlags::NONE);
        variable->ExoticName() = newDecl->AsImportDecl()->ImportName();
        bindings_.insert({newDecl->Name(), variable});
    }

    return true;
}

bool ModuleScope::ExportAnalysis()
{
    std::set<util::StringView> exportedNames;

    for (const auto &[exportDecl, decls] : exports_) {
        if (exportDecl->IsExportAllDeclaration()) {
            const auto *exportAllDecl = exportDecl->AsExportAllDeclaration();

            if (exportAllDecl->Exported() != nullptr) {
                auto result = exportedNames.insert(exportAllDecl->Exported()->Name());
                if (!result.second) {
                    return false;
                }
            }

            continue;
        }

        if (exportDecl->IsExportNamedDeclaration()) {
            const auto *exportNamedDecl = exportDecl->AsExportNamedDeclaration();

            if (exportNamedDecl->Source()) {
                continue;
            }
        }

        for (const auto *decl : decls) {
            binder::Variable *variable = FindLocal(decl->LocalName());

            if (!variable) {
                continue;
            }

            auto result = exportedNames.insert(decl->ExportName());
            if (!result.second) {
                return false;
            }

            if (!variable->IsModuleVariable()) {
                variable->AddFlag(VariableFlags::LOCAL_EXPORT);
                localExports_.insert({variable, decl->ExportName()});
            }
        }
    }

    return true;
}

// LocalScope

bool LocalScope::AddBinding(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                            [[maybe_unused]] ScriptExtension extension)
{
    return AddLocal(allocator, currentVariable, newDecl, extension);
}

void LoopDeclarationScope::ConvertToVariableScope(ArenaAllocator *allocator)
{
    if (NeedLexEnv()) {
        return;
    }

    for (auto &[name, var] : bindings_) {
        if (!var->LexicalBound() || !var->Declaration()->IsLetOrConstDecl()) {
            continue;
        }

        slotIndex_++;
        loopType_ = ScopeType::LOOP_DECL;
        auto *copiedVar = var->AsLocalVariable()->Copy(allocator, var->Declaration());
        copiedVar->AddFlag(VariableFlags::INITIALIZED | VariableFlags::PER_ITERATION);
        var->AddFlag(VariableFlags::LOOP_DECL);
        loopScope_->Bindings().insert({name, copiedVar});
    }

    if (loopType_ == ScopeType::LOOP_DECL) {
        slotIndex_ = std::max(slotIndex_, parent_->EnclosingVariableScope()->LexicalSlots());
        initScope_ = allocator->New<LocalScope>(allocator, parent_);
        initScope_->BindNode(node_);
        initScope_->Bindings() = bindings_;
    }
}

void LoopScope::ConvertToVariableScope(ArenaAllocator *allocator)
{
    declScope_->ConvertToVariableScope(allocator);

    if (loopType_ != ScopeType::LOCAL) {
        return;
    }

    for (const auto &[_, var] : bindings_) {
        (void)_;
        if (var->LexicalBound() && var->Declaration()->IsLetDecl()) {
            ASSERT(declScope_->NeedLexEnv());
            loopType_ = ScopeType::LOOP;
            break;
        }
    }

    if (loopType_ == ScopeType::LOOP) {
        slotIndex_ = std::max(slotIndex_, declScope_->LexicalSlots());
    }
}

bool CatchParamScope::AddBinding(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                                 [[maybe_unused]] ScriptExtension extension)
{
    return AddParam(allocator, currentVariable, newDecl, VariableFlags::INITIALIZED);
}

bool CatchScope::AddBinding(ArenaAllocator *allocator, Variable *currentVariable, Decl *newDecl,
                            [[maybe_unused]] ScriptExtension extension)
{
    if (!newDecl->IsVarDecl() && paramScope_->FindLocal(newDecl->Name())) {
        return false;
    }

    return AddLocal(allocator, currentVariable, newDecl, extension);
}

}  // namespace panda::es2panda::binder