Some background:
This is in the dreaded structure reorganization optimization that I'm
working on. It's running at LTRANS time with '-flto-partition=one'.
My issues in order of importance are:
1) In gimple-ssa.h, the equal method for ssa_name_hasher
has a segfault because the "var" field of "a" is (nil).
struct ssa_name_hasher : ggc_ptr_hash<tree_node>
{
/* Hash a tree in a uid_decl_map. */
static hashval_t
hash (tree item)
{
return item->ssa_name.var->decl_minimal.uid;
}
/* Return true if the DECL_UID in both trees are equal. */
static bool
equal (tree a, tree b)
{
return (a->ssa_name.var->decl_minimal.uid ==
b->ssa_name.var->decl_minimal.uid);
}
};
The parameter "a" is associated with "*entry" on the 2nd to last
line shown (it's trimmed off after that.) This from hash-table.h:
template<typename Descriptor, bool Lazy,
template<typename Type> class Allocator>
typename hash_table<Descriptor, Lazy, Allocator>::value_type &
hash_table<Descriptor, Lazy, Allocator>
::find_with_hash (const compare_type &comparable, hashval_t hash)
{
m_searches++;
size_t size = m_size;
hashval_t index = hash_table_mod1 (hash, m_size_prime_index);
if (Lazy && m_entries == NULL)
m_entries = alloc_entries (size);
#if CHECKING_P
if (m_sanitize_eq_and_hash)
verify (comparable, hash);
#endif
value_type *entry = &m_entries[index];
if (is_empty (*entry)
|| (!is_deleted (*entry) && Descriptor::equal (*entry, comparable)))
return *entry;
.
.
Is there any way this could happen other than by a memory corruption
of some kind? This is a show stopper for me and I really need some help on
this issue.
2) I tried to dump out all the gimple in the following way at the very
beginning of my program:
void
print_program ( FILE *file, int leading_space )
{
struct cgraph_node *node;
fprintf ( file, "%*sProgram:\n", leading_space, "");
// Print Global Decls
//
varpool_node *var;
FOR_EACH_VARIABLE ( var)
{
tree decl = var->decl;
fprintf ( file, "%*s", leading_space, "");
print_generic_decl ( file, decl, (dump_flags_t)0);
fprintf ( file, "\n");
}
FOR_EACH_FUNCTION_WITH_GIMPLE_BODY ( node)
{
struct function *func = DECL_STRUCT_FUNCTION ( node->decl);
dump_function_header ( file, func->decl, (dump_flags_t)0);
dump_function_to_file ( func->decl, file, (dump_flags_t)0);
}
}
When I run this the first two (out of three) functions print
just fine. However, for the third, func->decl is (nil) and
it segfaults.
Now the really odd thing is that this works perfectly at the
end or middle of my optimization.
What gives?
3) For my bug in (1) I got so distraught that I ran valgrind which
in my experience is an act of desperation for compilers.
None of the errors it spotted are associated with my optimization
(although it oh so cleverly pointed out the segfault) however it
showed the following:
==18572== Invalid read of size 8
==18572== at 0x1079DC1: execute_one_pass(opt_pass*) (passes.c:2550)
==18572== by 0x107ABD3: execute_ipa_pass_list(opt_pass*) (passes.c:2929)
==18572== by 0xAC0E52: symbol_table::compile() (cgraphunit.c:2786)
==18572== by 0x9915A9: lto_main() (lto.c:653)
==18572== by 0x11EE4A0: compile_file() (toplev.c:458)
==18572== by 0x11F1888: do_compile() (toplev.c:2302)
==18572== by 0x11F1BA3: toplev::main(int, char**) (toplev.c:2441)
==18572== by 0x23C021E: main (main.c:39)
==18572== Address 0x5842880 is 16 bytes before a block of size 88 alloc'd
==18572== at 0x4C3017F: operator new(unsigned long) (in
/usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==18572== by 0x21E00B7: make_pass_ipa_prototype(gcc::context*)
(ipa-prototype.c:329)
==18572== by 0x106E987: gcc::pass_manager::pass_manager(gcc::context*)
(pass-instances.def:178)
==18572== by 0x11EFCE8: general_init(char const*, bool) (toplev.c:1250)
==18572== by 0x11F1A86: toplev::main(int, char**) (toplev.c:2391)
==18572== by 0x23C021E: main (main.c:39)
==18572==
Are these known issues with lto or is this a valgrind issue?
Thanks,
Gary
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