[llvm-dev] clang-cl: building OpenSSL in 32 bit mode.

[David Major via llvm-dev]

I bet clang doesn't like that the LAZY() macros are referring to
OPENSSL_UplinkTable before it's been defined. To test this theory: does it
work if you move the LAZY()s after the table? (I guess you'd need to
forward-declare the lazy##i functions then too.)


On Wed, Sep 25, 2019 at 11:38 AM Tobias Hieta via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hello,
>
> As part of our efforts to replace MSVC with Clang on Windows we have
> started to rebuild our dependencies with clang-cl and lld-link.
>
> Most dependencies just needs very small adjustments to work, but one
> of our dependencies are OpenSSL. It required some editing of the build
> system to call clang-cl instead of clang. At the start I thought it
> worked just fine because it came all the way to the linking phase -
> but that then failed because the linker was running in 32 bit mode and
> it said that clang-cl had built 64 bit binaries. Turns out that I had
> to make more adjustments to forward the -m32 flag to clang-cl to get
> it to build. This unfortunately totally broke the build:
>
> clang-cl -m32 /Fotmp32dll\uplink.obj -Iinc32 -Itmp32dll /MD /Ox /O2
> /Ob2 -DOPENSSL_THREADS -DDSO_WIN32 -DW
> INVER=0x0601 -D_WIN32_WINNT=0x0601 -W3 -Gs0 -GF -Gy -nologo
> -DOPENSSL_SYSNAME_WIN32 -DWIN32_LEAN_AND_MEAN -DL_ENDIAN
> -D_CRT_SECURE_NO_DEPRECATE -D_WINSOCK_DEPRECATED_NO_WARNINGS
> -DOPENSSL_BN_ASM_PART
> _WORDS -DOPENSSL_IA32_SSE2 -DOPENSSL_BN_ASM_MONT -DOPENSSL_BN_ASM_GF2m
> -DRC4_ASM -DSHA1_ASM -DSHA256_ASM -DSHA512_ASM -DMD5_ASM -DRMD160_ASM
> -DAES_ASM -DVPAES_ASM -DWHIRLPOOL_ASM -DGHASH_ASM -DOPENSSL
> _USE_APPLINK -I. -DOPENSSL_NO_RC5 -DOPENSSL_NO_MD2 -DOPENSSL_NO_SSL2
> -DOPENSSL_NO_KRB5 -DOPENSSL_NO_JPAKE -DOPENSSL_NO_WEAK_SSL_CIPHERS
> -DOPENSSL_NO_STATIC_ENGINE /Zi /Fdtmp32dll/lib -D_WINDLL -c ms\
> uplink.c
> ms\uplink.c(106,1): error: asm operand has incomplete type 'void *[]'
> LAZY(1) LAZY(2) LAZY(3) LAZY(4) LAZY(5)
> ^
> ms\uplink.c(97,29): note: expanded from macro 'LAZY'
> _asm push OFFSET OPENSSL_UplinkTable \
> ^
> ms\uplink.c(106,1): error: asm operand has incomplete type 'void *[]'
> ms\uplink.c(100,22): note: expanded from macro 'LAZY'
> _asm jmp OPENSSL_UplinkTable+4*i }
> ^
> ms\uplink.c(106,1): error: use of undeclared label 'OPENSSL_UplinkTable'
> ms\uplink.c(100,22): note: expanded from macro 'LAZY'
> _asm jmp OPENSSL_UplinkTable+4*i }
> ^
>
> Dropping the -m32 flag makes this build without a problem. I had to
> dig around in the source and it seems like the _asm flags are only
> evaluated when we are building 32 bit which explains why it worked
> with 64bit, relevant code here:
>
>
> https://github.com/openssl/openssl/blob/OpenSSL_1_0_2-stable/ms/uplink.c#L95
>
> Is this expected? Just a missing feature of Clang?
>
> Thanks,
> Tobias
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20190925/515170ab/attachment-0001.html>