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Re: [PATCH/RFC] PR other/22313: Hot/cold sections vs. dwarf2 (take 2)

Roger Sayle wrote:
Hi David,

On Mon, 18 Sep 2006, David Daney wrote:

2006-08-31 Roger Sayle <>

	PR other/22313
	* dwarf2out.c (add_fde_cfi): Use a set_loc if the current label is
	NULL, otherwise use an advance_loc4 to adjust relative to the
	current label.
	(output_cfi) <DW_CFA_set_loc>: Update the current label.
	(dwarf2out_switch_text_section): Reset the current label to avoid
	using advance_loc4 over section boundaries.

This breaks exception handling on mipsel-linux-gnu. I did a regression hunt and r116604 (this patch) fails, where as r116603 works.

The problem is that with this patch applied the first instruction in a
FDE is typically DW_CFA_set_loc, before the patch it was DW_CFA_advance_loc.

Grr! Thanks for tracking down the change that broke EH on MIPS!

I think I can provide a temporary work-around for this problem (to
resolve the immediate regression) by initializing the current label
to the start of the function.  This'll mean that we'll resume using
advance_loc as the first instruction in the FDE.  However, profiled
bootstrap and/or hot/cold partitioning will still continue to introduce
DW_CFA_set_loc, which presumably can't be handled by current binutils.

Not ideal, but it will restore libgcj whilst the necessary bintuils
functionality is added.

Sorry for the inconvenience,

I just logged PR 29123 to track this issue.

David Daney

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