You could probably also write an assembly stub that does a tail call do the
same thing and avoid the compiler specific #pragmas.
My MASM is very rusty, but something like:
.code
EXTERNDEF SetMem32:PROC
;------------------------------------------------------------------------------
; VOID *
; EFIAPI
; memset (
; OUT VOID *Buffer, // RCX
; IN int Value, // RDX
; IN size_t Length // R8
; );
;------------------------------------------------------------------------------
memset PROC
;VOID *
;EFIAPI
;SetMem (
; OUT VOID *Buffer, // RCX
; IN UINTN Length, // RDX
; IN UINT8 Value // R8
; );
mov rax, r8
mov r8, rdx
mov rdx, rax
jmp SetMem32
memset ENDP
END
Thanks,
Andrew Fish
On Sep 5, 2013, at 4:21 PM, Varun Sampath <[email protected]> wrote:
> I think the error Lee is talking about is due to MSVC Whole Program
> Optimization. We were able to work around this by using #pragmas to tell MSVC
> to use our own functions for memcpy and memset instead of the compiler’s
> intrinsic implementations. These functions simply wrap around CopyMem() and
> SetMem().
>
> See
> http://stackoverflow.com/questions/2938966/how-to-use-vc-intrinsic-functions-w-o-run-time-library/2945619#2945619
> We were able to get this solution to work without disabling Whole Program
> Optimization with VS2010.
>
> -Varun
>
> From: Andrew Fish [mailto:[email protected]]
> Sent: Thursday, September 05, 2013 11:59 AM
> To: [email protected]
> Subject: Re: [edk2] "unresolved external _memset" build error and how to fix
> it
>
>
> On Sep 5, 2013, at 11:47 AM, "Hamel, Lee M" <[email protected]> wrote:
>
>
> If you get this build error "unresolved external _memset in aLibrary.lib
> (aSource.obj)"
>
> It takes a bit of time to solve because the build log doesn’t provide a
> detailed clue. One way the issue can show up is when you are looping over an
> array and setting the array item to 0. The compiler decides to use its
> intrinsic function _memset to set the array memory block to 0 instead of
> setting each item to 0.
>
> Offending code
> Corrected code
> MyMemSet((UINT8 *) &myarray, 0, sizeof(myarray));
>
> Is there a reason you could not use the
> https://svn.code.sf.net/p/edk2/code/trunk/edk2/MdePkg/Include/Library/BaseMemoryLib.h
> ZeroMem()?
>
>
> for (x = 0; x < MAX_X; x++) {
> for (y = 0; y < MAX_Y; y++) {
> myarray[x][y] = 0;
> } // y loop
> } // x loop
>
> You can track down the issue if you modify the library INF and add /FAcs
> build flag, e.g.
>
> [BuildOptions.common]
> MSFT:*_*_*_CC_FLAGS = /FAcs
>
> You can find where the compiler used its intrinsic function _memset as
> disassembly mixed with source code. View the file
>
> Build\YourPkg\<target>_<toolchain>\aPkg\Library\aLibrary\aLibrary\aSource.cod
> and search for _memset. The .cod file lists source line numbers to enable
> you to find where _memset is being used.
>
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