FYI: Copying the conversation.
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On 09/06/2022 18.31, Vince Del Vecchio wrote:
On Thu, Jun 9, 2022 at 10:34AM, Thomas Huth wrote:
On 09/06/2022 16.15, Claudio Fontana wrote:
On 6/9/22 13:27, Claudio Fontana wrote:
On 6/9/22 10:57, Daniel P. Berrangé wrote:
On Thu, Jun 09, 2022 at 10:47:24AM +0200, Thomas Huth wrote:
On 08/06/2022 17.51, Paolo Bonzini wrote:
On 6/3/22 19:35, Thomas Huth wrote:
On 03/06/2022 19.26, Claudio Fontana wrote:
[...]
maybe something we can now drop if there are no more C++ users?
I thought about that, too, but we still have disas/nanomips.cpp
left and the Windows-related files in qga/vss-win32/* .
That is pure C++ so it does not need the extra complication of
"detect whether the C and C++ compiler are ABI-compatible"
(typically due to different libasan/libtsan implementation between
gcc and clang). So it's really just nanoMIPS that's left.
Ok, so the next theoretical question is: If we get rid of the
nanomips.cpp file or convert it to plain C, would we then simplify
the code in configure again (and forbid C++ for the main QEMU
code), or would we rather keep the current settings in case we want
to re-introduce more C++ code again in the future?
It doesn't feel very compelling to have just 1 source file that's
C++ in QEMU. I'm curious how we ended up with this nanomips.cpp
file - perhaps it originated from another project that was C++ based
?
The code itself doesn't look like it especially needs to be using
C++. There's just 1 class there and every method is associated
with that class, and external entry point from the rest of QEMU is
just one boring method. Feels like it could easily have been done in
C.
Personally I'd prefer it to be converted to C, and if we want to add
any C++ in future it should be justified & debated on its merits,
rather than as an artifact of any historical artifacts such as the
code in configure happening to still exist.
I'll take a look at it, maybe I can turn it to C fairly quickly.
It seems to be generated code, getting the original authors involved in the
thread.
Not sure whether the original mips folks are still around ... but the folks
from MediaTek recently expressed their interest in nanoMIPS:
https://lore.kernel.org/qemu-devel/20220504110403.613168-8-stefan.pejic@syrmia.com/
Maybe they could help with the nanoMIPS disassembler?
I know it's likely a lot of work, but the best solution would maybe be to add
nanoMIPS support to capstone instead, then other projects could benefit from
the support in this library, too...
If I googled that right, there is a LLVM implementation of nanoMIPS available
here:
https://github.com/milos1397/nanomips-outliner/tree/master/llvm/lib/Target/Mips
... so maybe that could be used as input for capstone (which is based on llvm)?
Thomas
Yes, we are working on an LLVM port for nanoMIPS. It's functionally complete
and pretty usable, although we're still tuning performance. The more official
location is https://github.com/MediaTek-Labs/llvm-project.
However, for now we're still using the binutils assembler; there's no encoding
information in the current LLVM description. We have tentative plans to work
on encoding and integrated-as later this year. Correct me if I'm wrong, but I
would assume that, before that's available, it's not feasible to use capstone?
I'm also not very familiar with the way capstone translated the information
from LLVM into its disassembler source files, but I guess you're right -
this likely cannot work yet.
Regardless, I think we can look at converting the existing disassembler from
C++ to C. That would address the current concern, right?
Right - if it's not too much of a hassle that would be great!
Thomas
Hi everyone, I am interested in taking on this task.
Milica
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