Complete X86/x64 JIT and Remote Assembler for C++

by nkurz • 12 years ago

76 9 12 years ago

saurik• 12 years ago

Does anyone know what they mean by "remote"? I skimmed through the documentation, and it still is not clear. When I search for "remote assembler" the only results are 1) this project and 2) a kind of job in manufacturing (mostly with reference to mainframes).

nichtich• 12 years ago

I'm not sure either. My understanding is that they let you compile (part of) your program to a middle layer, a more abstract version of X86/64 instructions. And the binary then can be generated based on the actual machine using the instruction set that machine supports. So if some of the computation you do prefers a certain instruction, but you still what it to run without it, and you don't what the user to recompile from the source, then you can use this.

davepage• 12 years ago

Remote in the sense that a local assembler would be on the developer's system, and remote assembler is on the end user's system. Using this lib, the developer uses C++ as if it were metacode or a macro system to then emit machine code instructions on demand. This will presumably then execute faster than plain C++ in certain applications.

I can think of several interesting applications for this, such as text search.

stingraycharles• 12 years ago

Can you elaborate on the text search example? I genuinely have problems trying to find a fitting use case for this.

lovelearning• 12 years ago

From [1] and vmem.cpp, I believe it refers to the capability of injecting code into other processes.

[1] https://github.com/kobalicek/asmjit/blob/9ead0cfb4cb5eb1bcf8...

haberman• 12 years ago

Interesting. This seems to be more or less a C++ equivalent of DynASM (http://luajit.org/dynasm.html). Like DynASM, it lets you generate machine code at runtime. The library handles instruction encoding and linking of jump targets.

Like DynASM, it exposes the underlying architecture/instructions directly. It does not have an architecture-agnostic IR like LLVM.

It does do a little more than DynASM though. It provides (as an option) a higher-level interface that abstracts away ABI calling conventions and physical registers. It has a register allocator that assigns virtual registers to physical ones. It must also then be able to spill registers to the stack when necessary? It is interesting; I have not come across any assemblers that take this particular approach (native CPU instructions with virtual registers).

One thing that confused me about the title: the project exposes a C++ API, but it is not a JIT for compiling C++ programs themselves.

tiffanyh• 12 years ago

More information on DynASM can be found in the unofficial reference guide.

http://corsix.github.io/dynasm-doc/

Complete X86/x64 JIT and Remote Assembler for C++

Related Stories