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From: Claudio Fontana <cfontana@suse.de>
To: David Hildenbrand <david@redhat.com>,
	Cornelia Huck <cohuck@redhat.com>, Thomas Huth <thuth@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>
Cc: Halil Pasic <pasic@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	qemu-s390x@nongnu.org, qemu-devel@nongnu.org,
	Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC v2 04/13] target/s390x: remove tcg-stub.c
Date: Tue, 20 Apr 2021 15:35:40 +0200
Message-ID: <3218a4eb-c0f3-4cb6-3eae-78a1f9e1c393@suse.de> (raw)
In-Reply-To: <96f7ed07-137b-f337-4a00-77785d8e3bcc@redhat.com>

On 4/20/21 3:04 PM, David Hildenbrand wrote:
> On 20.04.21 15:00, Claudio Fontana wrote:
>> On 4/20/21 2:54 PM, David Hildenbrand wrote:
>>> On 20.04.21 12:36, Claudio Fontana wrote:
>>>> now that we protect all calls to the tcg-specific functions
>>>> with if (tcg_enabled()), we do not need the TCG stub anymore.
>>>
>>> You need compile-time checks, not runtime checks. Any calls have to be
>>> protected by #ifdef, otherwise the compiler might bail out.
>>
>> This is not true though, tcg_enabled() is #defined as 0 if tcg is not enabled.
>>
>> #define kvm_enabled()           (0)
>>
>> Compiler will elide the code if after the preprocessor pass the code is:
>>
>> if (0) {
>> }
>>
> 
> Just that we are talking about the same thing:
> 
> The following will fail to compile
> 
> void main(void)
> {
>          if (0) {
>                  return hello("Test");
>          }
> }
> 
> You at least need the prototypes. But I guess we still keep them and 
> really only remove the stubs -- which works because the linker will 
> never stumble over them.

Yes, thjs is what I am saying.

We have all the prototypes in sight, so we are good, no need to keep the stubs.

Ciao,

Claudio


  reply index

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-20 10:36 [RFC v2 00/13] s390x cleanup Claudio Fontana
2021-04-20 10:36 ` [RFC v2 01/13] hw/s390x: only build tod-qemu from the CONFIG_TCG build Claudio Fontana
2021-04-20 12:50   ` David Hildenbrand
2021-04-20 10:36 ` [RFC v2 02/13] hw/s390x: rename tod-qemu.c to tod-tcg.c Claudio Fontana
2021-04-20 12:49   ` David Hildenbrand
2021-04-20 10:36 ` [RFC v2 03/13] hw/s390x: tod: make explicit checks for accelerators when initializing Claudio Fontana
2021-04-20 12:52   ` David Hildenbrand
2021-04-20 10:36 ` [RFC v2 04/13] target/s390x: remove tcg-stub.c Claudio Fontana
2021-04-20 12:54   ` David Hildenbrand
2021-04-20 13:00     ` Claudio Fontana
2021-04-20 13:04       ` David Hildenbrand
2021-04-20 13:35         ` Claudio Fontana [this message]
2021-04-20 13:06   ` David Hildenbrand
2021-04-20 10:36 ` [RFC v2 05/13] target/s390x: start moving TCG-only code to tcg/ Claudio Fontana
2021-04-20 13:16   ` David Hildenbrand
2021-04-20 13:40     ` Claudio Fontana
2021-04-20 10:36 ` [RFC v2 06/13] target/s390x: move sysemu-only code out to cpu-sysemu.c Claudio Fontana
2021-04-20 10:36 ` [RFC v2 07/13] target/s390x: split cpu-dump from helper.c Claudio Fontana
2021-04-20 10:36 ` [RFC v2 08/13] target/s390x: make helper.c sysemu-only Claudio Fontana
2021-04-20 10:36 ` [RFC v2 09/13] target/s390x: use kvm_enabled() to wrap call to kvm_s390_get_hpage_1m Claudio Fontana
2021-04-20 10:36 ` [RFC v2 10/13] target/s390x: remove kvm-stub.c Claudio Fontana
2021-04-20 10:36 ` [RFC v2 11/13] target/s390x: move kvm files into kvm/ Claudio Fontana
2021-04-20 10:36 ` [RFC v2 12/13] target/s390x: split sysemu part of cpu models Claudio Fontana
2021-04-20 10:36 ` [RFC v2 13/13] MAINTAINERS: update s390x directories Claudio Fontana

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