[google gcc-4_9] fix undefined references in debug_info

[Rong Xu]

Hi,

This patch fixed a bug exposed in build kernel with fdo.

We cannot simply overwrite the bb footer in emit_barrier_after_bb as
the bb may already have a footer (in this case, a deleted label stmt).
We need to output this label because it's a user label and debug_info
has a reference to it.

Tested with problematic file and regression test.
Trunk may also have the same issue, but I need to work on a testcase.

Thanks,

-Rong

[Xinliang David Li]

This patch should be targeting trunk gcc?

David

Post by Rong Xu
Hi,
This patch fixed a bug exposed in build kernel with fdo.
We cannot simply overwrite the bb footer in emit_barrier_after_bb as
the bb may already have a footer (in this case, a deleted label stmt).
We need to output this label because it's a user label and debug_info
has a reference to it.
Tested with problematic file and regression test.
Trunk may also have the same issue, but I need to work on a testcase.
Thanks,
-Rong

[Teresa Johnson]

Yes, this needs to be fixed on trunk too. I looked at the history and
it has been this way (overwriting the footer) for years. It must be
uncommon to have this confluence of events.

Thanks,
Teresa

Post by Xinliang David Li
This patch should be targeting trunk gcc?
David

Post by Rong Xu
Hi,
This patch fixed a bug exposed in build kernel with fdo.
We cannot simply overwrite the bb footer in emit_barrier_after_bb as
the bb may already have a footer (in this case, a deleted label stmt).
We need to output this label because it's a user label and debug_info
has a reference to it.
Tested with problematic file and regression test.
Trunk may also have the same issue, but I need to work on a testcase.
Thanks,
-Rong