nudt-compiler-cpp/src/sem/SymbolTable.cpp

// 维护局部变量声明的注册与查找。

#include "include/sem/SymbolTable.h"

void SymbolTable::EnterScope() { scopes_.emplace_back(); }

void SymbolTable::ExitScope() {
  if (!scopes_.empty()) {
    scopes_.pop_back();
  }
}

void SymbolTable::Add(const std::string& name,
                      SysYParser::VarDefContext* decl) {
  if (scopes_.empty()) {
    EnterScope();
  }
  scopes_.back()[name] = decl;
}

bool SymbolTable::ContainsInCurrent(const std::string& name) const {
  if (scopes_.empty()) {
    return false;
  }
  return scopes_.back().find(name) != scopes_.back().end();
}

bool SymbolTable::Contains(const std::string& name) const {
  for (auto it = scopes_.rbegin(); it != scopes_.rend(); ++it) {
    if (it->find(name) != it->end()) {
      return true;
    }
  }
  return false;
}

SysYParser::VarDefContext* SymbolTable::Lookup(const std::string& name) const {
  for (auto it = scopes_.rbegin(); it != scopes_.rend(); ++it) {
    auto found = it->find(name);
    if (found != it->end()) {
      return found->second;
    }
  }
  return nullptr;
}