[cfe-dev] Linker error and obfuscated name

[Edward Diener]

On 8/3/2015 11:07 AM, Jonathan Roelofs wrote:
>
>
> On 8/2/15 10:54 PM, Edward Diener wrote:
>> When trying to link shared library BBB, which depends on shared library
>> AAA, I am getting a linker error of the form:
>>
>> throw_exception_ex.obj: In function
>> `Z15throw_exceptionI16ex_xml_exceptionEvRKT_':
>> throw_exception_ex.cpp:2: undefined reference to `typeinfo for
>> ex_xml_exception'
>>
>> How can I determine what functionality of ex_xml_exception in AAA the
>> throw_exception_ex code in BBB is not finding in order to link
>> successfully ?
>
> Is one of the libraries built with `-fno-rtti` and the other with `-frtti`?

No.

Here is the code and command lines:

// ex_decl.hpp

#ifndef EX_DECL_HPP
#define EX_DECL_HPP
#if defined(BLD_EX_EXAMPLE)
	#define EX_DECL __attribute__((__dllexport__))
#else
	#define EX_DECL __attribute__((__dllimport__))
#endif
#define EX_VISIBLE __attribute__((__visibility__("default")))
#endif // EX_DECL_HPP

// ex_exception.hpp

#ifndef EX_EXCEPTION_HPP
#define EX_EXCEPTION_HPP
#include <exception>
#include "ex_decl.hpp"
class EX_VISIBLE ex_exception :
     public virtual std::exception
{
private:
     char m_buffer[128];
protected:
     EX_DECL unsigned int append(unsigned int l, const char * a);
     EX_DECL ex_exception() ;
public:
     typedef enum {
       no_exception,
       other_exception
     } ex_exception_code;
     ex_exception_code code;
     EX_DECL ex_exception(ex_exception_code c,const char * e1 = 0,const 
char * e2 = 0) ;
     EX_DECL ex_exception(ex_exception const &) ;
     virtual EX_DECL ~ex_exception() throw() ;
     virtual EX_DECL const char * what() const throw() ;
};
#endif // EX_EXCEPTION_HPP

// ex_exception.cpp

#include <exception>
#include <cstring>
#define BLD_EX_EXAMPLE
#include "ex_exception.hpp"
EX_DECL unsigned int ex_exception::append(unsigned int l, const char * a){
     while(l < (sizeof(m_buffer) - 1)){
         char c = *a++;
         if('\0' == c)
             break;
         m_buffer[l++] = c;
     }
     m_buffer[l] = '\0';
     return l;
}
EX_DECL ex_exception::ex_exception(ex_exception_code c,const char * 
e1,const char * e2) : code(c)
{
     unsigned int length = 0;
     switch(code){
     case no_exception:
         length = append(length, "uninitialized exception");
         break;
     case other_exception:
         length = append(length, "unknown derived exception");
         break;
     default:
         length = append(length, "programming error");
         break;
     }
}
EX_DECL ex_exception::ex_exception(ex_exception const & oth) : 
std::exception(oth),code(oth.code)
{
	std::memcpy(m_buffer,oth.m_buffer,sizeof m_buffer);
}
EX_DECL ex_exception::~ex_exception() throw() {}
EX_DECL const char * ex_exception::what() const throw() { return m_buffer; }
EX_DECL ex_exception::ex_exception() : code(no_exception) {}

// Compile ex_exception.cpp

clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS 
-Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration -O0 -g 
-fno-inline -Wall -g -march=i686 -m32 -o "ex_exception.obj" 
"ex_exception.cpp"

// ex_xml_exception.hpp

#ifndef EX_XML_EXCEPTION_HPP
#define EX_XML_EXCEPTION_HPP
#include <exception>
#include "ex_decl.hpp"
#include "ex_exception.hpp"
class EX_VISIBLE ex_xml_exception :
     public virtual ex_exception
{
public:
     typedef enum {
         xml_archive_parsing_error,
         xml_archive_tag_mismatch,
         xml_archive_tag_name_error
     } ex_exception_code;
     EX_DECL ex_xml_exception(ex_exception_code c,const char * e1 = 
0,const char * e2 = 0);
     EX_DECL ex_xml_exception(ex_xml_exception const &) ;
     virtual EX_DECL ~ex_xml_exception() throw() ;
};
#endif // EX_XML_EXCEPTION_HPP

// ex_xml_exception.cpp

#include <exception>
#define BLD_EX_EXAMPLE
#include "ex_xml_exception.hpp"
EX_DECL ex_xml_exception::ex_xml_exception(ex_exception_code c,const 
char * e1,const char * e2) :
         ex_exception(other_exception, e1, e2)
     {
         switch(c){
         case xml_archive_parsing_error:
             ex_exception::append(0, "unrecognized XML syntax");
             break;
         case xml_archive_tag_mismatch:
             ex_exception::append(0, "XML start/end tag mismatch");
             if(0 != e1){
                 ex_exception::append(0, " - ");
                 ex_exception::append(0, e1);
             }
             break;
         case xml_archive_tag_name_error:
             ex_exception::append(0, "Invalid XML tag name");
             break;
         default:
             ex_exception::append(0, "programming error");
             break;
         }
     }
EX_DECL ex_xml_exception::ex_xml_exception(ex_xml_exception const & oth) 
: std::exception(oth),ex_exception(oth){}
EX_DECL ex_xml_exception::~ex_xml_exception() throw() {}

// Compile ex_xml_exception.cpp

clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS 
-Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration -O0 -g 
-fno-inline -Wall -g -march=i686 -m32 -o "ex_xml_exception.obj" 
"ex_xml_exception.cpp"

// Link exmp-clang37-d-1_59.dll

clang++.exe -o "exmp-clang37-d-1_59.dll" -Wl,-soname 
-Wl,exmp-clang37-d-1_59.dll -shared -Wl,--start-group "ex_exception.obj" 
"ex_xml_exception.obj"  -Wl,-Bstatic  -Wl,-Bdynamic  -Wl,--end-group -g 
-march=i686 -m32

// throw_exception_ex.cpp

#include "ex_xml_exception.hpp"
template<class E> void throw_exception(E const & e) { throw e; }
int main(int argc,char * argv[])
{
	if (argc > 1)
           {
 
throw_exception(ex_xml_exception(ex_xml_exception::xml_archive_parsing_error));
           }
	return 0;
}

// Compile throw_exception_ex.cpp

clang++.exe -c -x c++ -D__MINGW_FORCE_SYS_INTRINS 
-Wno-unused-local-typedef -Wno-dll-attribute-on-redeclaration -O0 -g 
-fno-inline -Wall -g -march=i686 -m32 -o "throw_exception_ex.obj" 
"throw_exception_ex.cpp"

// Link thr_exmp-clang37-d-1_59.dll

clang++.exe -o "thr_exmp-clang37-d-1_59.dll" -Wl,-soname 
-Wl,thr_exmp-clang37-d-1_59.dll -shared -Wl,--start-group 
"throw_exception_ex.obj" "exmp-clang37-d-1_59.dll"  -Wl,-Bstatic 
-Wl,-Bdynamic  -Wl,--end-group -g -march=i686 -m32

// Error message from this link

throw_exception_ex.obj: In function 
`Z15throw_exceptionI16ex_xml_exceptionEvRKT_':
throw_exception_ex.cpp:2: undefined reference to `typeinfo for 
ex_xml_exception'
clang++.exe: error: linker command failed with exit code 1 (use -v to 
see invocation)

Something is missing from ex_xml_exception which the link wants but I 
can not guess what it is.