I'm trying to register a pass in my gcc plugin code. To do so, I first declare the my_first_pass class which derives from gimple_opt_pass and, in turn, this class derives from opt_pass and so on... class my_first_pass : public gimple_opt_pass { public: my_first_pass(gcc::context * ctx) : gimple_opt_pass(my_first_pass_data, ctx) {} }; Then, I try to instantiate a my_first_pass object like in the code below, while configuring the remaining fields of the register_pass_info structure. struct register_pass_info pass_info; pass_info.pass = new my_first_pass(g/*gcc related global variable*/); ... To compile the above code, I generate a shared library which is then loaded by gcc. Whenever I run gcc I get the following error, which I know is caused by the creation of the my_first_pass object in the above code: cc1plus: error: cannot load plugin ./plugin.so ./structsizes.so: undefined symbol: _ZTI8opt_pass I'm following an online example, but if I run the $(GCC_SRC)/gcc/testsuite/gcc.dg/plugin/one_time_plugin.c I get the exact same problem. Tried with GCC 4.9.2 and 6.3.0 compiled from source. In both versions, I tried the testsuite code which register a pass, obtaining the same error. Thanks in advance, Cheers.