2

I have irony-mode configured and I'm using it for a C++-project. The code is built using Make. I have a number of different make targets to build the code; test code, release code, unit test code etc. Each make target uses its own set of compilation flags and the unit test code is placed in a subdirectory. All this makes using one single compilation database for irony-mode less than ideal.

For each make target I have defined a corresponding make target that runs the build through Bear to generate a compilation database for the specific make target. Then I try to make irony-mode switch to using this newly generated compilation database by running the function irony-cdb-json-select. It is documented as

Select CDB to use with a prompt.

It is useful when you have several CDBs with the same project
root.

But when I do irony-cdb-menu nothing has changed, the compilation flags that should have been there are not there.

How do I force irony-mode to update the compilation database?

Edited

Using one Make target for release code and another for unit tests means a specific source file can be compiled using two different sets of compile flags. Unit tests makes use of mock objects which means in this context the list of includes (-I) might differ compared to compiling release code. So depending on if I work on release code or unit tests I think I need two different compilation databases.

The file compile_commands.json generated by Bear contains an entry for each source file. Does irony-mode read each entry and use the specific settings for one specific source file? Or does irony-mode read the first entry in compile_commands.json and applies these settings to all source files in the project? I could create one compile_commands.json by appending output from release builds and unit test builds so that the resulting compile_commands.json would have entries with different sets of include flags (-I) without duplicates for the same file of course. Is irony-mode sensitive to this?

0

Why is using a single compilation database less than ideal? This is usually what people do. I agree, multi-databases support is useful to some build systems. I consider mostly for "full stack" build systems that some company and organizations have.

Would the compilation database be too big for all your targets? Taking a huge time to load?

Can't you dispatch the compilation database per directory? So if you have:

  • targetA/src/foo.cpp
  • targetB/src/bar.cpp

You could put the compile_commands.json in targetA/ and targetB/ respectively.

Anyway, your issue seems different here. If you call M-x irony-cdb-autosetup-compile-options RET manually, do you see something in M-x irony-cdb-menu RET?

Can you try on this sample project?

mkdir /tmp/testcdb
cd /tmp/testcdb
cat <<'EOF' > /tmp/testcdb/compile_commands.json
[
{
    "directory": "/tmp/testcdb",
    "command": "clang++ -std=c++11 -c foo.cpp -o foo.o"
    "file": "/tmp/testcdb/foo.cpp",
}
]
EOF
echo 'void f() { auto i = 0; }' > foo.cpp
emacs foo.cpp

Can you show me an extract of your generated compilation database? I just have an idea of what could be the issue, if the Bear version you use is recent, it's possible that it uses a new compilation database format that irony-mode does not support, and that your libclang may not also be lacking support for.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.