[Qt-creator] Bundling clang (for code model) with qt-creator package

[Andrzej Telszewski]

On 31/08/16 09:12, Eike Ziller wrote:
> The default path that the clang static analyzer checks is libexec/qtcreator/clang/ (+bin/clang etc)
> http://code.qt.io/cgit/qt-creator/qt-creator.git/tree/src/plugins/clangstaticanalyzer/clangstaticanalyzersettings.cpp#n61

> Our clang build:
> http://code.qt.io/cgit/qtsdk/qtsdk.git/tree/packaging-tools/build_clang.py

OK, I finally came to the point where QTC (4.2.0-rc1) does not build 
against my system LLVM (3.8.0).

I "parsed" qtsdk/packaging-tools/build_clang.py and 
qt-creator/scripts/deployqt.py for the clues on how to bundle Clang with 
QTC and got the idea. It actually seems to be quite simple... once you 
get the idea.

I detail my bundling steps below, together with some more questions.
I actually tested this configuration and it seems to work fine.

*1) Configure, build and temporarily install LLVM:*

$ tar xvf llvm-3.9.0.src.tar.xz
$ mv llvm-3.9.0.src llvm-src
$ cd llvm-src/tools
$ tar xvf cfe-3.9.0.src.tar.xz
$ mv cfe-3.9.0.src clang
$ cd -
$ cd llvm-src

$ mkdir build
$ cd build
$ cmake \
     -DCMAKE_INSTALL_PREFIX=/tmp/llvm-ins \
     -DCMAKE_BUILD_TYPE=Release \
     -G "Unix Makefiles" \
     -DLLVM_BUILD_TOOLS=OFF \
     -DLLVM_INCLUDE_EXAMPLES=OFF \
     -DLLVM_INCLUDE_TESTS=OFF \
     -DLLVM_ENABLE_RTTI=ON \
     -DLLVM_TARGETS_TO_BUILD="X86" \
     ..
   $ make
   $ make install
   $ # We disabled building of all the tools, but we still need some.
   $ make llvm-config
   $ cp -a bin/llvm-config /tmp/llvm-ins/bin
$ cd -

Questions:
1. In build_clang.py, depending on "bitness" (which I guess is x86 vs 
x86_64), you set -DLLVM_TARGETS_TO_BUILD=X86 in the case of 32 bits and 
-DLLVM_TARGETS_TO_BUILD=AArch64 in the case of 64 bits. Why is it so? In 
particular, why AArch64?
2. As you can see, I passed some additional flags (not found in 
build_clang.py), like -DLLVM_BUILD_TOOLS=OFF, mainly to shorten the 
build time. Can you think of any troubles I might get with the cmake 
configuration as you see above?
3. Are there any important flags missing compared to the ones generated 
by build_clang.py?
4. Are there any other flags that would be worth adding? Please note 
that I removed -DCMAKE_C_FLAGS and -DCMAKE_CXX_FLAGS for clarity, I 
actually have them in my real build/packaging script.

When it comes to build_clang.py, this script expects some environment 
variables, like PKG_NODE_ROOT, CLANG_BRANCH, and more:
1. Where do they come from? How can I get them? :-)
2. How can I determine which exact versions of software and any other 
flags you used to create the given QTC release?
3. There is apply_patches(): how can I know if you applied some patches 
and if so, where can I find them?

*2) Configure, build and temporarily install QTC:*

$ tar xvf qt-creator-opensource-src-4.2.0-rc1.tar.xz
$ cd qt-creator-opensource-src-4.2.0-rc1
$ qmake-qt5 qtcreator.pro \
     QTC_PREFIX=/usr \
     IDE_LIBRARY_BASENAME=lib \
     LLVM_INSTALL_DIR=/tmp/llvm-ins \
     QBS_INSTALL_DIR=/usr
$ make
$ make install INSTALL_ROOT=/tmp/qtc-ins
$ make docs
$ make install_docs INSTALL_ROOT=/tmp/qtc-ins

$ # Install LLVM/Clang bits needed for running QTC.
$ mkdir -p /tmp/qtc-ins/usr/libexec/qtcreator/clang/bin
$ cp -a /tmp/llvm-ins/bin/clang /tmp/qtc-ins/usr/libexec/qtcreator/clang/bin
$ cp -a /tmp/llvm-ins/bin/clang-3.9 
/tmp/qtc-ins/usr/libexec/qtcreator/clang/bin
$ mkdir -p /tmp/qtc-ins/usr/lib/qtcreator
$ cp -a /tmp/llvm-ins/lib/libclang.so* /tmp/qtc-ins/usr/lib/qtcreator
$ mkdir -p /tmp/qtc-ins/usr/libexec/qtcreator/clang/lib/clang
$ cp -a /tmp/llvm-ins/lib/clang/* 
/tmp/qtc-ins/usr/libexec/qtcreator/clang/lib/clang

Questions:
1. In deployqt.py, you tweak rpath-s, but I found that simply copying 
libclang into /tmp/qtc-ins/usr/lib/qtcreator just works. So is this step 
necessary? As a side note, I'm only bundling clang, as all the other 
libraries (including Qt) are already installed system-wide.

*3. I create the package out of /tmp/qtc-ins and I'm done.*

General question:
Have I missed something? ;-)

Some final notes:
- I'm building on x86_64 system,
- both Clang Code Model and Clang Static Analyzer seem to work just fine 
with the described build/install instructions,
- although I tried hard not to make a mistake, there might be some 
somewhere. I extracted and tweaked the commands from my build script for 
clarity. Anyways, the build and packaging works as expected using my 
build script.

I know I asked quite some count of questions.
Thanks in advance for the help!

-- 
Best regards,
Andrzej Telszewski