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Re: help with PR69133

On Mon, Jan 18, 2016 at 10:28 AM, Prathamesh Kulkarni
<> wrote:
> On 17 January 2016 at 14:56, Prathamesh Kulkarni
> <> wrote:
>> Hi,
>> I was having a look at PR69133.
>> It appears that with -flto-partition=none,
>> cgraph_node::get_untransformed_body ()
>> is called twice for node with asm_name _ZThn4_N11xercesc_3_11C5m_fn6ERKi.
>> c++filt says it is: non-virtual thunk to xercesc_3_1::C::m_fn6(int const&)
>> get_untransformed_body() calls
>> lto_free_function_in_decl_state_for_node() which sets
>> node->lto_file_data to NULL.
>> Now 2nd time get_untransformed_body is called for the same node,
>> node->lto_file_data is NULL and lto_get_decl_name_mapping() dereferences
>> lto_file_data which results in segfault.
>> I was wondering if gating on lto_file_data could be a reasonable solution ?
>> if (!lto_file_data)
>>   return false;
>> I am not sure what value to return for this case (I chose false
>> because of early exit).
>> It prevents the ICE, and the patch passes bootstrap+test on
>> x86_64-unknown-linux-gnu.
>> With partitoning enabled, for the above test-case,
>> get_untransformed_body () is called only once per node. However I
>> don't understand why it gets called twice with -flto-partition=none.
> Kugan pointed out to me the test-case doesn't ICE by passing -fno-ipa-icf.

It looks to me we are not supposed to call this twice on the same node
but nothing guards against that (and we don't release the untransformed
body either).  -flto-partition=none is special here becaue it combines WPA
and late stage.  IPA ICF is the only IPA pass needing untransformed bodies
during WPA.


> Thanks,
> Prathamesh
>> Thank you,
>> Prathamesh

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