It turned out to be the following: In multi source compile mode, I ggc_free() the data in dwarf2out.c after code generation for a file is done. (I found that I need this because otherwise the assembly code generated for file_2 to file_N of a compile job will carry leftovers from the code generated for file_1.)
This includes freeing the comp_unit_die. However, struct tree_type (tree.h) contains a union tree_type_symtab which has a member `die', and this may point to the comp_unit_die. gigi (ada/gcc-interface/trans.c) does not ggc_free the trees it allocates, therefore these trees continue to be alive even when the comp_unit_die was freed. So I guess I need to set TYPE_SYMTAB_DIE(t) to NULL on all nodes before freeing comp_unit_die. To be verified now. Thanks again Andrew. Oliver On Sat, 2009-08-15 at 20:00 +0100, Andrew Haley wrote: > Oliver Kellogg wrote: > > On Fri, 2009-08-14 at 10:41 +0100, Andrew Haley wrote: > >>> I am stuck here, i.e. I don't know how to find the code > >>> that is > >>> at fault. > >>> Is there some way to trace a pointer entered in > >>> G.free_object_list > >>> back to its origin in the code? > >> The usual way to find this is to use a gdb watchpoint. Find what object is > >> being freed, put a breakpoing on ggc_alloc_stat at the point the object is > >> created, and then put a watchpoint on the word that is being corrupted. > >> > >> Andrew. > > > > Thanks. > > I tried as follows: > > That's not gonna work. > > Put a breakpoint at the end of ggc_alloc_stat. It'll have to be a > conditional breakpoint on the address of the node that's being corrupted. > > When the object is created, add the watchpoint. > > Andrew.
