[PATCH] ArmVirtPkg/FdtPciPcdProducerLib: zero init local var to please GCC 4.8

[PATCH] ArmVirtPkg/FdtPciPcdProducerLib: zero init local var to please GCC 4.8

[Ard Biesheuvel]

GCC 4.8 in RELEASE mode complains about GetPciIoTranslation () potentially
not assigning IoTranslation, but does not notice that it returns failure in
this case, which means IoTranslation is never referenced *unless* it has
been assigned. So simply set IoTranslation to zero to help the compiler.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c b/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
index 10b47560cb9c..ea27cda7b77c 100644
--- a/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
+++ b/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
@@ -128,6 +128,7 @@ FdtPciPcdProducerLibConstructor (
 
       PcdSetBool (PcdPciDisableBusEnumeration, FALSE);
 
+      IoTranslation = 0;
       RetStatus = GetPciIoTranslation (FdtClient, Node, &IoTranslation);
       if (!RETURN_ERROR (RetStatus)) {
           PcdSet64 (PcdPciIoTranslation, IoTranslation);
-- 
2.7.4

Re: [PATCH] ArmVirtPkg/FdtPciPcdProducerLib: zero init local var to please GCC 4.8

[Laszlo Ersek]

On 09/05/16 09:56, Ard Biesheuvel wrote:
> GCC 4.8 in RELEASE mode complains about GetPciIoTranslation () potentially
> not assigning IoTranslation, but does not notice that it returns failure in
> this case, which means IoTranslation is never referenced *unless* it has
> been assigned. So simply set IoTranslation to zero to help the compiler.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c b/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
> index 10b47560cb9c..ea27cda7b77c 100644
> --- a/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
> +++ b/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
> @@ -128,6 +128,7 @@ FdtPciPcdProducerLibConstructor (
>  
>        PcdSetBool (PcdPciDisableBusEnumeration, FALSE);
>  
> +      IoTranslation = 0;
>        RetStatus = GetPciIoTranslation (FdtClient, Node, &IoTranslation);
>        if (!RETURN_ERROR (RetStatus)) {
>            PcdSet64 (PcdPciIoTranslation, IoTranslation);
> 

Ouch. This is exactly why "IoTranslation = 0" appeared at the beginning,
in commit 65bb13b0fd7f ("ArmVirtualizationPkg/VirtFdtDxe: parse
"pci-host-ecam-generic" properties"), and why we've been carrying it
around, most recently in commit d4cb9a30494d ("ArmVirtPkg: implement
FdtPciHostBridgeLib"). We forgot about it in commit c8f1a75aa997
("ArmVirtPkg/FdtPciPcdProducerLib: add handling of PcdPciIoTranslation").

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Thanks
Laszlo

Re: [PATCH] ArmVirtPkg/FdtPciPcdProducerLib: zero init local var to please GCC 4.8

[Ard Biesheuvel]

On 5 September 2016 at 12:41, Laszlo Ersek <lersek@redhat.com> wrote:
> On 09/05/16 09:56, Ard Biesheuvel wrote:
>> GCC 4.8 in RELEASE mode complains about GetPciIoTranslation () potentially
>> not assigning IoTranslation, but does not notice that it returns failure in
>> this case, which means IoTranslation is never referenced *unless* it has
>> been assigned. So simply set IoTranslation to zero to help the compiler.
>>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> ---
>>  ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c b/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
>> index 10b47560cb9c..ea27cda7b77c 100644
>> --- a/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
>> +++ b/ArmVirtPkg/Library/FdtPciPcdProducerLib/FdtPciPcdProducerLib.c
>> @@ -128,6 +128,7 @@ FdtPciPcdProducerLibConstructor (
>>
>>        PcdSetBool (PcdPciDisableBusEnumeration, FALSE);
>>
>> +      IoTranslation = 0;
>>        RetStatus = GetPciIoTranslation (FdtClient, Node, &IoTranslation);
>>        if (!RETURN_ERROR (RetStatus)) {
>>            PcdSet64 (PcdPciIoTranslation, IoTranslation);
>>
>
> Ouch. This is exactly why "IoTranslation = 0" appeared at the beginning,
> in commit 65bb13b0fd7f ("ArmVirtualizationPkg/VirtFdtDxe: parse
> "pci-host-ecam-generic" properties"), and why we've been carrying it
> around, most recently in commit d4cb9a30494d ("ArmVirtPkg: implement
> FdtPciHostBridgeLib"). We forgot about it in commit c8f1a75aa997
> ("ArmVirtPkg/FdtPciPcdProducerLib: add handling of PcdPciIoTranslation").
>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>

Pushed, thanks.