Re: [PATCH] Release build in GCC5 has warning message Wreturn-local-addr in HashPeiLib

["Yao, Jiewen" <jiewen.yao@intel.com>]

Could you please show me how this function returns *local variable*?

return BuildGuidDataHob (&mHashLibPeiRouterGuid, &LocalHashInterfaceHob, sizeof (LocalHashInterfaceHob));


I don't understand the analysis.


> -----Original Message-----
> From: Lu, Pen-ChunX <pen-chunx.lu@intel.com>
> Sent: Thursday, April 27, 2023 3:58 PM
> To: Yao, Jiewen <jiewen.yao@intel.com>; devel@edk2.groups.io
> Cc: Wang, Jian J <jian.j.wang@intel.com>
> Subject: RE: [PATCH] Release build in GCC5 has warning message Wreturn-
> local-addr in HashPeiLib
> 
> Hi,
>  It means the code might be possible return local variable address when we
> used the function.
>  So I allocate a resource to local variable to avoid this.
> 
> Best Regards,
> Joe Lu
> 
> -----Original Message-----
> From: Yao, Jiewen <jiewen.yao@intel.com>
> Sent: Thursday, April 27, 2023 3:51 PM
> To: Lu, Pen-ChunX <pen-chunx.lu@intel.com>; devel@edk2.groups.io
> Cc: Wang, Jian J <jian.j.wang@intel.com>
> Subject: RE: [PATCH] Release build in GCC5 has warning message Wreturn-
> local-addr in HashPeiLib
> 
> Hi
> I am not sure if I can understand the patch.
> 
> Would you please clarify what the problem is in the original code?
> 
> > -----Original Message-----
> > From: Lu, Pen-ChunX <pen-chunx.lu@intel.com>
> > Sent: Thursday, April 27, 2023 2:59 PM
> > To: devel@edk2.groups.io
> > Cc: Lu, Pen-ChunX <pen-chunx.lu@intel.com>; Yao, Jiewen
> > <jiewen.yao@intel.com>; Wang, Jian J <jian.j.wang@intel.com>
> > Subject: [PATCH] Release build in GCC5 has warning message
> > Wreturn-local- addr in HashPeiLib
> >
> > CC: Jiewen Yao <jiewen.yao@intel.com>
> > CC: Jian J Wang <jian.j.wang@intel.com>
> > Signed-off-by: JoeX Lu <pen-chunx.lu@intel.com>
> > ---
> >  .../HashLibBaseCryptoRouterPei.c                | 17 +++++++++++++----
> >  1 file changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git
> >
> a/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterP
> > ei.c
> >
> b/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterP
> > ei.c
> > index eeb424b6c3..bf7a5fc65c 100644
> > ---
> >
> a/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterP
> > ei.c
> > +++
> >
> b/SecurityPkg/Library/HashLibBaseCryptoRouter/HashLibBaseCryptoRouterP
> > ei.c
> > @@ -84,11 +84,20 @@ InternalCreateHashInterfaceHob (
> >    EFI_GUID  *Identifier
> >    )
> >  {
> > -  HASH_INTERFACE_HOB  LocalHashInterfaceHob;
> > +  HASH_INTERFACE_HOB  *LocalHashInterfaceHob;
> HASH_INTERFACE_HOB
> > + *HobBuffer;
> >
> > -  ZeroMem (&LocalHashInterfaceHob, sizeof (LocalHashInterfaceHob));
> > -  CopyGuid (&LocalHashInterfaceHob.Identifier, Identifier);
> > -  return BuildGuidDataHob (&mHashLibPeiRouterGuid,
> > &LocalHashInterfaceHob, sizeof (LocalHashInterfaceHob));
> > +  HobBuffer = NULL;
> > +  LocalHashInterfaceHob = AllocateZeroPool (sizeof
> > (HASH_INTERFACE_HOB));
> > +  if (LocalHashInterfaceHob == NULL) {
> > +    return NULL;
> > +  }
> > +  CopyGuid (&LocalHashInterfaceHob->Identifier, Identifier);
> > + HobBuffer = (HASH_INTERFACE_HOB*) BuildGuidDataHob
> > (&mHashLibPeiRouterGuid, LocalHashInterfaceHob, sizeof
> > (LocalHashInterfaceHob));
> > +  if (LocalHashInterfaceHob != NULL) {
> > +    FreePool (LocalHashInterfaceHob);  }  return HobBuffer;
> >  }
> >
> >  /**
> > --
> > 2.31.1.windows.1