增加了多重括号的处理

src/SysYIRGenerator.cpp

@@ -492,4 +492,8 @@ namespace sysy
     builder.setPosition(rhs_block, rhs_block->begin());
     return (ctx->exp()[1]->accept(this));
   }
+  any SysYIRGenerator::visitParenExp(SysYParser::ParenExpContext *ctx)
+  {
+    return ctx->exp()->accept(this);
+  }
 } // namespace sysy

src/SysYIRGenerator.h

@@ -180,10 +180,7 @@ namespace sysy
 
     virtual std::any visitUnaryExp(SysYParser::UnaryExpContext *ctx) override;
 
-    virtual std::any visitParenExp(SysYParser::ParenExpContext *ctx) override
-    {
-      return visitChildren(ctx);
-    }
+    virtual std::any visitParenExp(SysYParser::ParenExpContext *ctx) override;
 
     virtual std::any visitStringExp(SysYParser::StringExpContext *ctx) override
     {