The perl_tsa_mutex_lock Symbol Cannot Be Found

Error Information

Can't load 'xxx.so' for module threads: xxx.so: undefined symbol: perl_tsa_mutex_lock at xxx

Problem

The /usr/lib64/perl5/CORE/perl.h file contains the following definitions:

##if ... 
    defined(__clang__) 
    ... 
##  define PERL_TSA__(x)   __attribute__((x)) 
##  define PERL_TSA_ACTIVE 
##else 
##  define PERL_TSA__(x)   /* No TSA, make TSA attributes no-ops. */ 
##  undef PERL_TSA_ACTIVE 
##endif 
 
##ifdef PERL_TSA_ACTIVE 
EXTERN_C int perl_tsa_mutex_lock(perl_mutex* mutex) 
  PERL_TSA_ACQUIRE(*mutex) 
  PERL_TSA_NO_TSA; 
EXTERN_C int perl_tsa_mutex_unlock(perl_mutex* mutex) 
  PERL_TSA_RELEASE(*mutex) 
  PERL_TSA_NO_TSA; 
##endif##endif

The mutex-related symbols used by Clang are perl_tsa_* symbols with a thread safety flag. However, libperl.so does not contain the symbols. As a result, link errors occur.

Solution

• Use libperl.so that contains perl_tsa_* symbols (during compilation of libperl.so, add the USE_ITHREADS and I_PTHREAD macros).
• Delete the predefined macro __clang__ as follows:

clang -U__clang__ ...