Re: [Qemu-devel] WE NEED GCC 4 please

[Johannes Schindelin]

Hi,

On Mon, 21 Jan 2008, Andreas Färber wrote:

> Am 21.01.2008 um 12:18 schrieb Johannes Schindelin:
> 
> > The miniops right now are implemented as plain C commands.  If the 
> > "good" gcc guys would not have insisted on not having an option to 
> > force the "ret" or "jmp" statement at the end of the function, we 
> > could use them for _all_ processors.
> > 
> > As it is, Fabrice's code generator will most likely be something 
> > similar to Paul's qops, which means that you have to invent a 
> > "primitive C" in which to write the miniops, and you will have to 
> > write a backend for _each_ and _every_ host CPU you support.
> 
> Has anyone looked into the idea of manually generating machine 
> instructions through preprocessor macros at runtime, then jumping there? 
> That's what the Mono JIT does, leaving C compilers completely out of the 
> picture.

I had looked at GNU lightning briefly (but it only supports x86, SPARC 
and PowerPC), and at LLVM (but it was too complex, and only supports 
JITting for X86, X86-64, PowerPC and PowerPC-64; although they have "An 
easily retargettable code generator, which currently supports X86, X86-64, 
PowerPC, PowerPC-64, ARM, Thumb, SPARC, Alpha, and IA-64.).

Given the unwillingness of Fabrice to rely on some external project, 
though, I gave up even before I had something even rudimentary.

Ciao,
Dscho