On Tue, Jun 30, 2020 at 11:49:01 +0100, PierreGondois wrote:
> From: Pierre Gondois <pierre.gond...@arm.com>
>
> The following build configrations:
> build -b DEBUG -a AARCH64 -t VS2017 -p edk2\EmbeddedPkg\EmbeddedPkg.dsc
> build -b NOOPT -a AARCH64 -t VS2017 -p edk2\EmbeddedPkg\EmbeddedPkg.dsc
> build -b RELEASE -a AARCH64 -t VS2017 -p edk2\EmbeddedPkg\EmbeddedPkg.dsc
>
> are generating the following build errors:
> edk2\EmbeddedPkg\Library\AndroidBootImgLib\AndroidBootImgLib.c(100):
> error C2036: 'void *': unknown size
> edk2\EmbeddedPkg\Library\AndroidBootImgLib\AndroidBootImgLib.c(347):
> error C2036: 'void *': unknown size
>
> Since the size of void* depends on the architecture, it can be
> dangerous to use void* pointer arithmetic. Plus the C99 doesn't state
> that void* pointer arithmetic is allowed.
> This patch adds a cast to fix the Visual Studio errors reported.
>
> Signed-off-by: Pierre Gondois <pierre.gond...@arm.com>
> ---
>
> The changes can be seen at:
> https://github.com/PierreARM/edk2/commits/831_Fix_VS2017_build_error_v1
>
> Notes:
> v1:
> - Fix VS2017 build errors. [Pierre]
>
> EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c | 13 ++++++++-----
> 1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> b/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> index
> e1036954ee586dfc30266eec2897d71bfc949038..bbe0d41018b3d5665c72ee61efe737ae57b1b2eb
> 100644
> --- a/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> +++ b/EmbeddedPkg/Library/AndroidBootImgLib/AndroidBootImgLib.c
> @@ -1,6 +1,6 @@
> /** @file
>
> - Copyright (c) 2013-2014, ARM Ltd. All rights reserved.<BR>
> + Copyright (c) 2013-2020, ARM Ltd. All rights reserved.<BR>
> Copyright (c) 2017, Linaro. All rights reserved.
>
> SPDX-License-Identifier: BSD-2-Clause-Patent
> @@ -97,7 +97,7 @@ AndroidBootImgGetKernelInfo (
> ASSERT (IS_VALID_ANDROID_PAGE_SIZE (Header->PageSize));
>
> *KernelSize = Header->KernelSize;
> - *Kernel = BootImg + Header->PageSize;
> + *Kernel = (UINT8*)BootImg + Header->PageSize;
The reason I prefer my version, although this one would also solve the
compilation error, is that I really don't like casts to char * (which
this effectively is) as a workaround.
The problem I have with it is that a cast is a signal of intent (this
thing that we have been viewing as an X should now be seen as a Y) -
and the intent here is simply to get the side effect that a char has a
known size of 1 (whereas a void doesn't).
I will admit it is the first time I have seen it used for this purpose
:)
The same problem occure when casting to char * in order to not have to
deal with pointer arithmetic at all or to avoid thinking about
alignment requirements. And both of these are frequently indicators of
buggy code.
/
Leif
> return EFI_SUCCESS;
> }
>
> @@ -339,9 +339,12 @@ AndroidBootImgUpdateFdt (
> goto Fdt_Exit;
> }
>
> - Status = AndroidBootImgSetProperty64 (UpdatedFdtBase, ChosenNode,
> - "linux,initrd-end",
> - (UINTN)(RamdiskData + RamdiskSize));
> + Status = AndroidBootImgSetProperty64 (
> + UpdatedFdtBase,
> + ChosenNode,
> + "linux,initrd-end",
> + (UINTN)((UINT8*)RamdiskData + RamdiskSize)
> + );
> if (EFI_ERROR (Status)) {
> goto Fdt_Exit;
> }
> --
> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
>
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