Export global constants

[sarranz]

Could we add assembler directives to export global variables? For instance, for

u64 g = 42;

it would be good to be able to access g from C.

[bgregoir]

Can we ensure that g will not be modified external code ?

[vbgl]

What’s the motivation?

[xvzcf]

What’s the motivation?

I asked about this; I wanted to have a file for "API constants" as follows:

require "parameters.jinc"

u64 c_VERIFICATION_KEY_SIZE = VERIFICATION_KEY_SIZE;
u64 c_SIGNING_KEY_SIZE = SIGNING_KEY_SIZE;
...

Jasmin could print the values of the constants above when invoked as jasminc file.jazz -pcstexp, and this output could be parsed, but if it could compile the file to a set of exportable global variables, benchmarking and testing programs could generically refer to these constants (which would be supplied at their compile time).

[vbgl]

Easy workaround: you can define functions that simply return the values of these constants.

[xvzcf]

Easy workaround: you can define functions that simply return the values of these constants.

I was hoping for a way to get the constants at compile-time, but yes I can do it this way, it's no big deal.

[vbgl]

The thing is that it is difficult to have both 1) the ability to refer to constants from the outside and 2) the possibility of building shared libraries.

[vbgl]

Related PR turning off the export of global data: #41