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The default when running static languages like C++ or Rust or Go via Sulong is to stick to the memory layout chosen by the programmer. There is no conversion to

The default when running static languages like C++ or Rust or Go via Sulong is to stick to the memory layout chosen by the programmer. There is no conversion to typical JVM memory layouts. Nor does running on the JVM has major restrictions for the framework (we are working on a version that does not run on the JVM in the SubstrateVM project). What Graal+Truffle allows is for library writers and language designers to invent new representations without any restrictions on the layout and have them interact with the rest of the system. We want programmers to use the best language for the task. And even combine multiple languages within one program. Foreign objects can be passed around freely as parameters and local variables, but there are restrictions when building combined data structures - e.g., if you have a highly optimized native data structure, it is not possible to install a pointer to a JavaScript object in it without performance loss.

nostrademons 10y ago
Interesting. So, if I'm understanding this correctly - Truffle allows a language designer to specify a certain logical layout for data structures, along with hints for how this will get converted to a physical memory layout. Language implementors also get the full power of Graal for lowering their AST to machine code and other compiler tasks. On cross-language boundaries, it generates automatic accessors for other languages to access that data, using the logical layout to identify how particular fields need to be pulled out and manipulated, but not requiring that the full data structure be converted across the foreign-call boundary. One consequence of this is that nesting & embedding of data structures may require an explicit conversion, since if an object is a hashtable in Javascript but a packed series of fields in C, it's obviously not going to fit. Sorta like SWIG++? If you could do SWIG but never require that an end-user write a typemap or debug a crash themself, there'd probably be a big market for that.
- thomaswue 10y ago
  Yes, this is an excellent description.

nostrademons 10y ago

Interesting. So, if I'm understanding this correctly - Truffle allows a language designer to specify a certain logical layout for data structures, along with hints for how this will get converted to a physical memory layout. Language implementors also get the full power of Graal for lowering their AST to machine code and other compiler tasks. On cross-language boundaries, it generates automatic accessors for other languages to access that data, using the logical layout to identify how particular fields need to be pulled out and manipulated, but not requiring that the full data structure be converted across the foreign-call boundary. One consequence of this is that nesting & embedding of data structures may require an explicit conversion, since if an object is a hashtable in Javascript but a packed series of fields in C, it's obviously not going to fit. Sorta like SWIG++? If you could do SWIG but never require that an end-user write a typemap or debug a crash themself, there'd probably be a big market for that.

thomaswue 10y ago
Yes, this is an excellent description.