In astartup.asm I expected ifdef PROFILE_GRAPH / endif around:

public profile_current_cost_centre

profile_current_cost_centre label ptr dq 0

You removed a dq 0 in astartup.asm:

garbage_collector_name: ifndef PROFILE_GRAPH dq 0 endif db "garbage_collector" db 0

But in macho64/astartup.s you added a quad 0:

garbage_collector_name: .if !PROFILE_GRAPH .quad 0 .endif .quad 0 .ascii "garbage_collector" .byte 0

Is this intended ?

profile_current_cost_centre is exported because it is used in GraphCopy. It must be present in the other runtime systems as well to prevent linking errors.

The change to macho64/astartup.s should have been the same as the one to astartup.asm. I have fixed this now, thanks.

I also noticed that my latest change to count tail calls and returns was not applied to macho64/aprofilegraph.s. I have pushed this as well now.

In functions code_build_u and code_fill_u are 3 tests of callgraph_profiling.
The last one can be merged with the previous one if you replace:
		parameter->p=graph_5;
with
		parameter[b_size].p=graph_5;

Could you also remove unnecessary changes to the number of tabs in empty lines and
add an empty line after the declaration of INSTRUCTION_GRAPH graph_5 ?

Not all labels have a label_name, so test if label_name!=NULL before using strcmp in cgaas.c and cgawas.c.