[cfe-dev] clang and Crypto++

[Marshall Clow]

After Doug fixed bug #7851 yesterday (thanks, Doug!), I decided to see if crypto++ <http://www.cryptopp.com/> would build with clang TOT.

Answer: No, it does not.

There are three problems:

1) the crypto++ sources make unqualified calls to member functions in base classes; clang flags this as an error.

> clang++ -DNDEBUG -g -O2 -arch x86_64 -arch i386 -DCRYPTOPP_DISABLE_ASM -pipe -c panama.cpp
> panama.cpp:425:2: error: use of undeclared identifier 'PadLastBlock'
>        PadLastBlock(this->BLOCKSIZE, 0x01);
>        ^
>        this->
> panama.cpp:500:22: note: in instantiation of member function
>      'CryptoPP::Weak::PanamaHash<CryptoPP::EnumToType<CryptoPP::ByteOrder, 1>
>> ::TruncatedFinal' requested here
> template class Weak::PanamaHash<BigEndian>;
>                     ^
> In file included from panama.cpp:9:
> In file included from ./panama.h:5:
> ./iterhash.h:38:7: note: must qualify identifier to find this declaration in dependent
>      base class
>        void PadLastBlock(unsigned int lastBlockSize, byte padFirst=0x80);
>             ^
> panama.cpp:425:2: error: no member named 'PadLastBlock' in
>      'CryptoPP::Weak::PanamaHash<LittleEndian>'
>        PadLastBlock(this->BLOCKSIZE, 0x01);
>        ^~~~~~~~~~~~
> panama.cpp:501:22: note: in instantiation of member function
>      'CryptoPP::Weak::PanamaHash<CryptoPP::EnumToType<CryptoPP::ByteOrder, 0>
>> ::TruncatedFinal' requested here
> template class Weak::PanamaHash<LittleEndian>;
>                     ^
> In file included from panama.cpp:9:
> In file included from ./panama.h:4:
> In file included from ./strciphr.h:31:
> In file included from ./seckey.h:9:

This is easy to fix in crypto++; just follow the fixit hint (and I have submitted these changes to the crypto++ project)

2) clang asserts when compiling vmac.cpp <http://llvm.org/bugs/show_bug.cgi?id=8913>

3) clang is much, much slower than gcc 4.2.1 when building crypto++.
On my 2007 MacPro:
	gcc takes 8m40s to build.
	clang (TOT this morning) takes much longer; there is one file - sha.cpp which takes over 30 minutes, if it ever does finish, but all the other files combined take more than 45 minutes.

I'm quite happy to provide the modified crypto++ distro in case anyone else is interested in pursuing this.

-- Marshall