Re: [edk2-devel] [PATCH 1/1] MdeModulePkg/DxeIplPeim: Initialize pointer PageMapLevel5Entry

["Laszlo Ersek" <lersek@redhat.com>]

On 08/14/19 09:37, Zhang, Shenglei wrote:
> Initialize PageMapLevel5Entry at the beginning of the function.
> 
> This commit will fix a GCC 4.8.5 build failure introduced by commit
> b3527dedc3951f061c5a73cb4fb2b0f95f47e08b.
> 
> OvmfPkg build failure wtih gcc 4.8.5 still exists at latest edk2 version.
> The commit 46f8a6891606746ca8b1e684ac379ce271306dc0 seems not to fix
> the build failure completely.
> 
> Cc: Dandan Bi <dandan.bi@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
> ---
>  MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> index 2389f3eb485b..aae80536ac3d 100644
> --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> @@ -652,6 +652,8 @@ CreateIdentityMappingPageTables (
>    UINT64                                        AddressEncMask;
>    IA32_CR4                                      Cr4;
>  
> +  PageMapLevel5Entry = NULL;
> +
>    //
>    // Make sure AddressEncMask is contained to smallest supported address field
>    //
> 

If you are convinced that we need this assignment *only* for suppressing
an invalid compiler warning, then please add a comment about it:

  //
  // set PageMapLevel5Entry to suppress incorrect compiler/analyzer
  // warnings
  //

Related documentation BZ:

https://bugzilla.tianocore.org/show_bug.cgi?id=607

... Just a suggestion from my side; I defer to the MdeModulePkg maintainers.

Thanks
Laszlo