Clang linker issues (from source, to gcc-snapshot)

Question

I cannot seem to get this to work. I configured with the --with-gcc-toolchain= where after the equals I put the directory where gcc was (/usr/lib/gcc-snapshot/bin).

I also looked into the answers to " clang linker problem" but I do not see how I can get the accepted answer to find the correct location, and the symlink answer would have worked, except that all of the directories that it is searching exist (copying the lib folder from gcc-snapshot to one of the include locations does not seem to help).

As suggested in the other question, the output of clang++ test.cpp -v:

bob@bob:~/programming$ clang++ test.cpp -v
clang version 3.3 (trunk 171350)
Target: x86_64-unknown-linux-gnu
Thread model: posix
"/home/bob/programming/build/Release+Asserts/bin/clang" -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -main-file-name test.cpp -mrelocation-model static -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-linker-version 2.22 -momit-leaf-frame-pointer -v -resource-dir /home/bob/programming/build/Release+Asserts/bin/../lib/clang/3.3 -fmodule-cache-path /var/tmp/clang-module-cache -internal-isystem /usr/local/include -internal-isystem /home/bob/programming/build/Release+Asserts/bin/../lib/clang/3.3/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir /home/bob/programming -ferror-limit 19 -fmessage-length 80 -mstackrealign -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -backend-option -vectorize-loops -o /tmp/test-PWiB4M.o -x c++ test.cpp
clang -cc1 version 3.3 based upon LLVM 3.3svn default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/include
/home/bob/programming/build/Release+Asserts/bin/../lib/clang/3.3/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
test.cpp:1:10: fatal error: 'iostream' file not found
#include ^
1 error generated.

clang version 3.3 (trunk revision 171350)

EDIT: There are no .o files in the Release+Asserts folder for the build. Is this normal? If not, why is this the case, and how can I fix it (if I can point it as clang's stdlib, then that works as well).

Edit 2: It also fails to compile int main(){return 0;} as it can't find crtbegin.o. Full output is as follows:

/usr/bin/ld: cannot find crtbegin.o: No such file or directory
/usr/bin/ld: cannot find -lgcc
/usr/bin/ld: cannot find -lgcc_s
clang: error: linker command failed with exit code 1 (use -v to see invocation)

The results after -v are the same as the above, but with the ending error being different.

Config.log:
The full file can be found here, but the first (non-comment) line is: $ ../llvm/configure --with-gcc-toolchain=/usr/lib/gcc-snapshot/gcc

Answer 1

The issue that we've identified is that gcc was installed with --prefix=/usr/lib/gcc-snapshot configure argument. and llvm was configured with --with-gcc-toolchain=/usr/lib/gcc-snapshot/gcc argument. It should be the same as the gcc installation prefix, i.e. --with-gcc-toolchain=/usr/lib/gcc-snapshot.

The question's current first line says " I configured with the --with-gcc-toolchain= where after the equals I put the directory where gcc was (/usr/lib/gcc-snapshot/bin).", and the current last line says "first (non-comment) line is: $ ../llvm/configure --with-gcc-toolchain=/usr/lib/gcc-snapshot/gcc"

That's puzzling, you might have thought that you had put the flag --with-gcc-toolchain=/usr/lib/gcc-snapshot/bin but you had actually put --with-gcc-toolchain=/usr/lib/gcc-snapshot/gcc

Regardless, I think you should try the following.

1. remove or rename the build directory (the directory where you ran the configure command, i.e. the directory where you found the config.log file) I assume it's the /home/bob/programming/build directory.
2. now create /home/bob/programming/build directory again. it should be empty now.
3. cd /home/bob/programming/build
4. run the following configure command ../llvm/configure --with-gcc-toolchain=/usr/lib/gcc-snapshot
5. follow through with the rest of your build process.

The issue seems to be that you didn't specify the gcc-toolchain prefix correctly. It should be the same as the --prefix parameter you used while configuring the gcc.

Report back the results here.

Also see Clang 3.2 build broken after building gcc 4.7