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Date: Wed, 12 Jun 2024 03:28:47 -0500
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Thomas Huth <thuth@redhat.com>, kvm@vger.kernel.org,
        linux-s390@vger.kernel.org, Andrew Jones <andrew.jones@linux.dev>,
        Marc Hartmayer <mhartmay@linux.ibm.com>, kvm-riscv@lists.infradead.org,
        kvmarm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org
Subject: Re: [kvm-unit-tests PATCH] build: retain intermediate .aux.o targets
Message-ID: <20240612082847.GG19790@gate.crashing.org>
References: <20240612044234.212156-1-npiggin@gmail.com>
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On Wed, Jun 12, 2024 at 02:42:32PM +1000, Nicholas Piggin wrote:
> arm, powerpc, riscv, build .aux.o targets with implicit pattern rules
> in dependency chains that cause them to be made as intermediate files,
> which get removed when make finishes. This results in unnecessary
> partial rebuilds. If make is run again, this time the .aux.o targets
> are not intermediate, possibly due to being made via different
> dependencies.
> 
> Adding .aux.o files to .PRECIOUS prevents them being removed and solves
> the rebuild problem.
> 
> s390x does not have the problem because .SECONDARY prevents dependancies
> from being built as intermediate. However the same change is made for
> s390x, for consistency.

This is exactly what .SECONDARY is for, as its documentation says,
even.  Wouldn't it be better to just add a .SECONDARY to the other
targets as well?


Segher