Re: [Qemu-devel] gcc as a backend to generate better code

[Fabrice Bellard]

Johan Rydberg wrote:
> The TODO file states the following:
>
> - use gcc as a backend to generate better code (easy to do by using
>   op-i386.c operations as local inline functions).
>
> How would this be done, actually?

The executable is launched at least once with the standard QEMU to 
record translation block statistics, location and code reference (from 
which file it comes, at which offset).

Then an off-line tool is launched to convert recorded translation blocks 
to a .so file using gcc by generating C code from each micro operation.

When QEMU is launched again, it can scan a directory containing .so 
files for all statically compiled programs. Then it can load the 
corresponding .so file and use the translated blocks stored inside.

With this method, only heavily used translations blocks are compiled 
with gcc. The rest is translated with QEMU.

Fabrice.