Hi all, The JIT work finally reached an important step in the past week: there is an RPython interface between the JIT frontend and any possible machine-code-level backend. The interface (called RGenOp and To Be Documented Soon, Tm) has two implementations so far: * codegen/llgraph/rgenop.py that produces flow graphs again (don't look, it's quite obscure to do that while still being RPython enough). It is for testing only, so far. * codegen/i386/ri386genop.py that produces i386 ("IA32", more precisely) machine code into mmap-ed memory blocks. There are some basic tests about using the interface in i386/test/test_ri386genop.py. The tests there have the following structure: * def make_xxx(): this is an example RPython function that calls the rgenop interface to generate some simple code. * def test_xxx_interpret(): tries to run make_xxx() with the codegen/llgraph implementation, and then llinterprets the produced graph. * def test_xxx_direct(): tries to run make_xxx() with the codegen/i386 implementation, and then executes the machine code. Gets nice segfaults if the machine code is wrong. * def test_xxx_compile(): compiles the make_xxx() function into a stand-alone executable (via the normal genc route). This is where we check that our ri386genop implementation is really RPython code only. A hint about the "token" thingy: there are many rgenop.xxxToken() static methods that are here basically because we cannot dynamically handle in RPython code objects like low-level types. So a "token" is whatever RPython value that the back-end needs in order to perform a specific operation on that type. Each variant of token can be anything - it's returned by rgenop only to be passed back to it - but they must be RPython values. For example, 'fieldToken(T, name)' makes a token that is passed back to methods like genop_getfield(). For the i386 backend, the fieldToken is simply an integer: the offset of the field in the structure T. This is used by genop_getfield() to encode the offset in the machine instruction. In this way, genop_getfield() is a completely RPython-friendly function, and only fieldToken() needs to be special (a memo static method). More in the above-promized documentation :-) A bientot, Armin