Duplicated definitions on generated code

[mingodad]

When trying to build https://github.com/GaloisInc/cclyzerpp with the latest souffle I was getting several link time errors see here GaloisInc/cclyzerpp#141 due to duplicated symbols at link time when trying to use more than one souffle generated sources in the same application/library.

But using the exact souffle-2.3 builds without problems, probably a regression or unintended changes happened ?

[ruricolist]

We're seeing the same problem with ddisasm. The change is that since 4008db6 Souffle separates definitions out of declarations. This means the definitions are no longer implicitly declared inline and the linker won't allow multiple compiled Souffle outputs to be linked together.

[mingodad]

Hello @ruricolist can you make a pull request ?
Looking through your repository it seems that you have a fix for this.

[quentin]

As part of a larger set of changes, I added an option to specify a namespace for the generated code so that several programs may be instanciated: quentin@2f86f7b

I might progressively contribute the branch in a near future.

[ruricolist]

In the meantime this patch can be used to allow Souffle to output files that can be compiled and linked: master...ruricolist:souffle:master

Note that either way, executables generated by linking multiple Souffle files will now be much larger (because the linker can no longer eliminate duplicate methods).

Edit: ruricolist@1ac5e27 is preferable to the above (it is deterministic).