forked from ppxf25tqu/nudt-compiler-cpp
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53 lines
1.3 KiB
53 lines
1.3 KiB
// 极简语义分析：只检查变量是否先声明再使用。
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#include "sem/Sema.h"
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#include <stdexcept>
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#include <string>
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#include <unordered_set>
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#include "ast/AstNodes.h"
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#include "sem/SymbolTable.h"
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namespace {
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class SemaVisitor {
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public:
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explicit SemaVisitor(SymbolTable& table) : table_(table) {}
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void CheckBlock(const ast::Block& block) {
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for (const auto& decl : block.varDecls) {
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table_.Add(decl->name);
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if (decl->init) CheckExpr(*decl->init);
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}
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for (const auto& stmt : block.stmts) {
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if (auto ret = dynamic_cast<ast::ReturnStmt*>(stmt.get())) {
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CheckExpr(*ret->value);
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}
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}
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}
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void CheckExpr(const ast::Expr& expr) {
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if (auto var = dynamic_cast<const ast::VarExpr*>(&expr)) {
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if (!table_.Contains(var->name)) {
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throw std::runtime_error("使用了未定义的变量: " + var->name);
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}
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} else if (auto bin = dynamic_cast<const ast::BinaryExpr*>(&expr)) {
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CheckExpr(*bin->lhs);
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CheckExpr(*bin->rhs);
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}
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}
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private:
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SymbolTable& table_;
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};
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} // namespace
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std::shared_ptr<ast::CompUnit> RunSema(std::shared_ptr<ast::CompUnit> ast) {
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if (!ast || !ast->func || !ast->func->body) return ast;
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SymbolTable table;
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SemaVisitor visitor(table);
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visitor.CheckBlock(*ast->func->body);
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return ast;
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}
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