Re: [edk2-devel] including redfish libs results in multiple definitions of symbols

["Andrew Fish" <afish@apple.com>]

In edk2 speak Base just means does not depend on any phase of boot, so basically standalone code. So you can pull a Base lib into SEC, PEI, DXE, SMM, etc. 

We never interned different Class Names for libs to map to the same library class when we designed the build system. 

One of the driving factors for the library classes was to not have to change your vendors driver INF file id you wanted to use a different instance of the DebugLib etc.

Thanks,

Andrew Fish

> On May 25, 2022, at 9:07 PM, Ethin Probst <harlydavidsen@gmail.com> wrote:
> 
> aren't the Base*Libs there in case you want to override existing implementations or implement custom versions of them? I'm pretty sure that's the logic behind it -- its a hack of sorts to try to get OOP out of a purely procedural language. It works, but I don't think its necessarily ideal. But there really isn't much of an alternative. Then again, I might be wrong, too...
> 
> On 5/25/22 23:04, Andrew Fish via groups.io wrote:
>>> On May 25, 2022, at 9:23 AM, M.T. <xzavierpower@gmail.com <mailto:xzavierpower@gmail.com>> wrote:
>>> 
>>> Hello
>>> 
>>> I'm working on a small UEFI shell app.
>>> I was hoping to make use of the JsonLib found in the Redfish Package.
>>> 
>>> When I include the Redfish JsonLib and it's dependencies:
>>> JsonLib|RedfishPkg/Library/JsonLib/JsonLib.inf
>>> Ucs2Utf8Lib|RedfishPkg/Library/BaseUcs2Utf8Lib/BaseUcs2Utf8Lib.inf
>>> RedfishCrtLib|RedfishPkg/PrivateLibrary/RedfishCrtLib/RedfishCrtLib.inf
>>> BaseSortLib|MdeModulePkg/Library/BaseSortLib/BaseSortLib.inf
>>> 
>>> BaseSortLib has symbol clashes with SortLib resulting in the following:
>>> 
>> It looks like BaseSortLib and and SortLib are the same library class so you should only have one.
>> /Volumes/Case/edk2(master)*>*git grep --recurse-submodules SortLib  -- \*.inf | grep LIBRARY_CLASS
>> MdeModulePkg/Library/BaseSortLib/BaseSortLib.inf:18:  LIBRARY_CLASS                   = SortLib
>> MdeModulePkg/Library/UefiSortLib/UefiSortLib.inf:18:  LIBRARY_CLASS                   = SortLib|UEFI_APPLICATION UEFI_DRIVER UEFI_DRIVER DXE_RUNTIME_DRIVER DXE_DRIVER
>> /Volumes/Case/edk2(master)*>*git grep --recurse-submodules BaseSortLib  -- \*.inc
>> RedfishPkg/RedfishLibs.dsc.inc:16:*BaseSortLib*|MdeModulePkg/Library/*BaseSortLib*/*BaseSortLib*.inf
>> OK bingo bingo bingo….
>> The way the edk2 works is you have a library class that maps to the include file. This is the name in the INF file that resolves linking. You can have as many instances of the library class as you like. This is why the DSC files have the <library class name>|<path to INF file> syntax as you are letting the build pick which instance of the library to use. You can control this per driver/app if you want.
>> It looks to me like BaseSortLib is an alias for SortLib and that is a bit of hack.
>> You could try making sure that BaseSortLib and SortLib point to the same library instance
>> The other option would be to edit RedfishCrtLib.inf and make BaseSortLib SortLib
>> /Volumes/Case/edk2(master)*>*git grep --recurse-submodules BaseSortLib  -- \*.inf
>> MdeModulePkg/Library/BaseSortLib/BaseSortLib.inf:13:  BASE_NAME                       = *BaseSortLib*
>> MdeModulePkg/Library/BaseSortLib/BaseSortLib.inf:14:  MODULE_UNI_FILE                 = *BaseSortLib*.uni
>> MdeModulePkg/Library/BaseSortLib/BaseSortLib.inf:25:*BaseSortLib*.c
>> RedfishPkg/PrivateLibrary/RedfishCrtLib/RedfishCrtLib.inf:28:*BaseSortLib*
>> I’m note sure why this fake BaseSortLib exists. Looks like we would need to ask Abner?
>> *
>> *
>> commit 6e9233f968735219b2038c5dd23a46be2c021807
>> Author: Abner Chang <abner.chang@hpe.com <mailto:abner.chang@hpe.com>>
>> Date:   Fri Dec 4 12:30:05 2020 +0800
>>     RedfishPkg/RedfishCrtLib: Redfish C runtime library
>>     Redfish CRT library is currently used by edk2 JsonLib
>>     (open source jansson project) and edk2 RedfishLib
>>     (libredfish open source project). Redfish CrtLib library
>>     provides the necessary C runtime equivalent edk2 functions
>>     for open source projects.
>>     Signed-off-by: Abner Chang <abner.chang@hpe.com <mailto:abner.chang@hpe.com>>
>>     Cc: Leif Lindholm <leif@nuviainc.com <mailto:leif@nuviainc.com>>
>>     Cc: Nickle Wang <nickle.wang@hpe.com <mailto:nickle.wang@hpe.com>>
>>     Cc: Peter O'Hanley <peter.ohanley@hpe.com <mailto:peter.ohanley@hpe.com>>
>>     Reviewed-by: Nickle Wang <nickle.wang@hpe.com <mailto:nickle.wang@hpe.com>>
>>     Acked-by: Leif Lindholm <leif@nuviainc.com <mailto:leif@nuviainc.com>>
>>     Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com <mailto:michael.d.kinney@intel.com>>
>> *
>> *
>> Thanks,
>> Andrew Fish
>>> /usr/bin/ld: UefiSortLib.obj (symbol from plugin): in function `PerformQuickSort':
>>> (.text+0x0): multiple definition of `PerformQuickSort'; BaseSortLib.obj (symbol from plugin):(.text+0x0): first defined here
>>> /usr/bin/ld: UefiSortLib.obj (symbol from plugin): in function `PerformQuickSort':
>>> (.text+0x0): multiple definition of `DevicePathCompare'; BaseSortLib.obj (symbol from plugin):(.text+0x0): first defined here
>>> /usr/bin/ld: UefiSortLib.obj (symbol from plugin): in function `PerformQuickSort':
>>> (.text+0x0): multiple definition of `StringNoCaseCompare'; BaseSortLib.obj (symbol from plugin):(.text+0x0): first defined here
>>> /usr/bin/ld: UefiSortLib.obj (symbol from plugin): in function `PerformQuickSort':
>>> (.text+0x0): multiple definition of `StringCompare'; BaseSortLib.obj (symbol from plugin):(.text+0x0): first defined here
>>> 
>>> I need SortLib for UEFIShell dependencies, and I need BaseSortLib for JsonLib.
>>> Is there some way around this?  Or is Redfish meant to be standalone?
>>> 
>>> Thank you in advance
>>> xp
>>