Re: [PATCH] ArmPlatformPkg: eliminate Juno gcc build warning

[Ryan Harkin <ryan.harkin@linaro.org>]

On 20 June 2017 at 12:28, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
> (+ Laszlo)
>
> On 20 June 2017 at 13:00, Leif Lindholm <leif.lindholm@linaro.org> wrote:
>> When building without LTO, gcc incorrectly resolves the hazards for
>> 'PciRegBase’ when inlining, leading to "may be used uninitialized"
>> warnings (and hence build failure with -Werror).
>> Eliminate this warning by explicitly initializing the variable to 0.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
>
> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Reviewed-by: Ryan Harkin <ryan.harkin@linaro.org>

>
>> ---
>>
>> For those who have heard me mentioning this before but arguing against
>> upstreaming this patch: I only just tweaked that this warning doesn't
>> go away with more recent toolchains, but simply when switching to GCC5
>> build profile, and hence LTO. Build failure still reproducible with
>> gcc 6.3.1 and GCC49.
>>
>
> /me annoyed
>
> We keep hitting this with GCC, and I profoundly dislike having to add
> redundant initialization sequences. Is there any other solution
> possible, e.g., disable this warning for certain builds?
>
>>  ArmPlatformPkg/ArmJunoPkg/Drivers/ArmJunoDxe/ArmJunoDxe.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/ArmPlatformPkg/ArmJunoPkg/Drivers/ArmJunoDxe/ArmJunoDxe.c b/ArmPlatformPkg/ArmJunoPkg/Drivers/ArmJunoDxe/ArmJunoDxe.c
>> index da93eb5829..18491c7378 100644
>> --- a/ArmPlatformPkg/ArmJunoPkg/Drivers/ArmJunoDxe/ArmJunoDxe.c
>> +++ b/ArmPlatformPkg/ArmJunoPkg/Drivers/ArmJunoDxe/ArmJunoDxe.c
>> @@ -343,6 +343,7 @@ ArmJunoSetNicMacAddress ()
>>      return Status;
>>    }
>>
>> +  PciRegBase = 0;
>>    Status = InitPciDev (PciIo, &PciRegBase, &OldPciAttr);
>>    if (EFI_ERROR (Status)) {
>>      return Status;
>> --
>> 2.11.0
>>