How to install CLang using precompiled binaries? - c++

Question

How do I install CLang on Ubuntu, using precompiled binaries of CLang that I downloaded?
Here's how I downloaded CLang: "LLVM Download Page" -> "Download LLVM 3.2" -> "Clang Binaries for Ubuntu-12.04/x86_64" ( http://llvm.org/releases/3.2/clang+llvm-3.2-x86_64-linux-ubuntu-12.04.tar.gz .)
Then, I expanded the archive into a folder on my Ubuntu 12.04 LTS 64-bit machine. The contents of the expanded folder look like this:
$ ls clang+llvm-3.2-x86_64-linux-ubuntu-12.04
bin docs include lib share
Question: What do I do next? Do I have to copy these into some folders myself, and if so, which ones exactly? Most instructions I found online are for building CLang from source, which doesn't apply here.
I am a newbie to most of these tools. I created a basic hello-world C++ program, and was able to compile and run it, using GCC and autotools. Now, I want to compile the same program with CLang.

Answer 1

You can follow the same step as mentioned in https://askubuntu.com/questions/89615/how-do-i-install-llvm-clang-3-0
using GNU tar:
wget <clang-binaries-tarball-url> # or `curl -O <url>`
tar xf clang*
cd clang*
sudo cp -R * /usr/local/
If your tar isn't GNU and
the archive you get is .tar.gz, you can use tar -xzf;
if you have .tar.xz archive, you can use tar -xJf;
for .tar.bz2 archive, you can use tar -xjf.

Answer 2

Assuming you compiled your program with g++ hello.cpp
The equivalents of gcc and g++ are clang and clang++ accordingly. They are found in the bin folder.
It doesn't matter where you place the folders of clang, what matters is you don't move them later. So place them somewhere (I prefer $HOME and I'll assume this for the next)
Then:
Prepend it to $PATH variable
export PATH=~/clang+llvm-3.2-x86_64-linux-ubuntu-12.04/bin/:$PATH
Make this permanent by adding it to ~/.bashrc
echo "export PATH=~/clang+llvm-3.2-x86_64-linux-ubuntu-12.04/bin/:\$PATH" >> ~/.bashrc
Now you can do clang++ hello.cpp

Answer 3

I would like to install clang in /home/s. i.e.,
/home/s
bin
lib
include
...
I did the following in Ubuntu:
wget <clang-binaries-tarball-url>
sudo tar -xf <clang+llvm-..tar.xz> --strip-components=1 -C /home/s
# Set the path environmental variable
export PATH=/home/s/bin:$PATH
# Tell ldconfig about new shared library in /home/s/lib
cd /home/s
cat > libs.conf << "END"
/home/s/lib
END
sudo mv libs.conf /etc/ld.so.conf.d/libs.conf
sudo ldconfig
To test it:
clang --version
The output is:
clang version 7.0.0 (tags/RELEASE_700/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/s/bin
Let's test C++17 Filesystem withex1.cpp
#include <iostream>
#include <filesystem>
int main() {
for(auto &file : std::filesystem::recursive_directory_iterator("./")) {
std::cout << file.path() << '\n';
}
}
Compile it
clang++ -std=c++17 -stdlib=libc++ -Wall -pedantic ex1.cpp -o ex1 -lc++fs
Run it
./ex1
The output:
"./ex1"
"./ex1.cpp"