[cfe-dev] [cfe-commits] Design proposal: Add custom compilation database formats as plugins

[Sean Silva]

> For ninja in particular, I have long thought that the correct approach is to write something which can convert 'ninja -t commands' into the JSON format, or to build a tool for writing the JSON database directly into ninja.

This was my line of thought as well.

Since the C++ stdlib unfortunately doesn't have JSON support, what do
you think about a simpler, more plaintext-y compilation database
(PlaintextCompilationDatabase?); it seems like that might be a win
since it is simpler to output. For example, the format would just be

/path/to/dir/
clang++ foo.cpp
foo.cpp
<empty line>

Just a mirror of the JSON one, but with a format easier to output (god
forbid there's a newline in one of the command lines or filenames). On
the other hand, throwing together a simple "good-enough" JSON writer
isn't *too* difficult; nonetheless, for tools written in C/C++, this
could lower the bar to entry. Do you know what CMake currently does?
Does it have its own mini JSON writer?

--Sean Silva

On Wed, Jul 18, 2012 at 2:54 PM, Chandler Carruth <chandlerc at google.com> wrote:
> On Wed, Jul 18, 2012 at 2:45 PM, Sean Silva <silvas at purdue.edu> wrote:
>>
>> I was looking at adding compilation database support for ninja build
>> files. However, I ran into the problem that it basically amounted to
>> rewriting the entire ninja build file parser that is already
>> implemented inside of ninja. As such, it seems like the very nature of
>> compilation databases is something that needs to be output by the tool
>> configuring/doing the build.
>>
>> Is your thought with this that, for example, ninja would provide a
>> compilation database plugin reusing its own parser?
>
>
> For ninja in particular, I have long thought that the correct approach is to
> write something which can convert 'ninja -t commands' into the JSON format,
> or to build a tool for writing the JSON database directly into ninja. Then
> CMake (or anything else that generates the build file) can inject targets to
> automatically generate and update this file. This includes re-building
> generated source files as necessary.
>
> I think for OSS build systems and systems that are largely
> command-line-driven like ninja, the file output and interchange system is a
> much better alternative. The plugin support I think is mostly useful for
> stateful build systems which may really need to implement the database using
> custom logic.