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From: "tromey at sourceware dot org" <sourceware-bugzilla@sourceware.org>
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Subject: [Bug macros/27754] Excessive CPU load and memory usage with -g3
 debug info
Date: Mon, 10 May 2021 14:51:27 +0000
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https://sourceware.org/bugzilla/show_bug.cgi?id=3D27754

--- Comment #9 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Richard Biener from comment #6)
> The non-LTO .debug_macro has
>=20
>  DW_MACRO_import - offset : 0x0
>  DW_MACRO_end_file
>=20
> as well, whatever that means.

The problem with LTO is that the output is pathological.
For example I see this sequence:

 DW_MACRO_import - offset : 0x0
 DW_MACRO_end_file
 DW_MACRO_import - offset : 0x0
 DW_MACRO_end_file
 DW_MACRO_import - offset : 0x0
 DW_MACRO_end_file

This says to import the macros from offset 0 three times in succession.
While this is technically ok, it's also absurd.  Is this really
intentional? This file imports the unit at offset 0x0 multiple times
-- 108 in fact.

We can probably work around it in gdb somehow.  My first thought is
to have it simply skip multiple imports of the same unit.  This could
in theory yield the wrong answer sometimes, though.

Looks vaguely related to bug#26303, in the "suspicious import" sense.

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