[erlang-questions] erlang 20.0 under elbrus: compilation problems

[Mikael Pettersson]

Max Lapshin writes:
 > Hi.
 > 
 > trying to build erlang 20 under elbrus computer  (arch e2k), it goes with
 > compiler lcc
 > 
 > trying to configure with:
 > 
 > ./configure --prefix=/opt/flussonic --enable-smp-support
 > --enable-kernel-poll --enable-hipe --without-java --enable-dirty-schedulers
 > 
 > erts/configure fails, in erts/config.log I see:
 > 
 > 
 > 
 > 
 > | #define SIZEOF_TIME_T 8
 > 
 > | /* end confdefs.h.  */
 > 
 > |
 > 
 > | /* pr36339.c */
 > 
 > | extern void abort (void);
 > 
 > |
 > 
 > | typedef unsigned long my_uintptr_t;
 > 
 > |
 > 
 > | int check_a(my_uintptr_t tagged_ptr);
 > 
 > |
 > 
 > | int __attribute__((noinline)) try_a(my_uintptr_t x)
 > 
 > | {
 > 
 > |   my_uintptr_t heap[2];
 > 
 > |   my_uintptr_t *hp = heap;
 > 
 > |
 > 
 > |   hp[0] = x;
 > 
 > |   hp[1] = 0;
 > 
 > |   return check_a((my_uintptr_t)(void*)((char*)hp + 1));
 > 
 > | }
 > 
 > |
 > 
 > | int __attribute__((noinline)) check_a(my_uintptr_t tagged_ptr)
 > 
 > | {
 > 
 > |   my_uintptr_t *hp = (my_uintptr_t*)(void*)((char*)tagged_ptr - 1);
 > 
 > |
 > 
 > |   if (hp[0] == 42 && hp[1] == 0)
 > 
 > |     return 0;
 > 
 > |   return -1;
 > 
 > | }
 > 
 > |
 > 
 > | int main(void)
 > 
 > | {
 > 
 > |   if (try_a(42) < 0)
 > 
 > |     abort ();
 > 
 > |   return 0;
 > 
 > | }
 > 
 > |
 > 
 > configure:34880: result: yes
 > 
 > configure:34883: error: This gcc miscompiles the Erlang runtime system;
 > please use a different version
 > 
 > 
 > I have commented this place in configure and after some other patches it
 > has compiled.
 > 
 > 
 > Is it a fatal error?

Yes.  This is a test for GCC's bug PR36339, which appeared with gcc-4.3.0
and which broke the Erlang VM.  Note that it actually checks for the
miscompile, not for a compiler version, so the bug is really present.

The solution, as configure correctly says, is to use a different compiler.