Re: [Valgrind-developers] Followup to c5218ff4c and some VEX cleanup

[Florian K. <fl...@ei...>]

Hi Paul,

thanks for looking at it.

On 06.07.25 22:15, Paul Floyd via Valgrind-developers wrote:
> 
> 
> For point 2
> 
> hd_fpu.c looks very old, pre-Valgrind even. The missing header looks like a 
> precursor to config.h and will probably be fairly easy to recreate. 

hd_fpu.c doesn't even have a main function. do_one_insn_fp is the entry
point which is a decoder. So you could possibly construct a main loop around it 
reading insns from some file or so. Still there are missing functions
that will prevent linking e.g. getIMem4, regno_from_modRM and amode_from_modRM
that do not exist elsewhere in the valgrind tree.

> x87_to_vex_and_back.c which is missing some riscv64 pieces. I'd need to get it 
> working in order to comment how useful it might be. Our x87 support is not 
> great, but no-one has time to work on it.
> 

OK, so we keep that one.

> smchash.c looks like a tool for checking hash values. Is that still of any use? 

Probably not. Nobody has used it when I was working on V between 2010 and 2016.

> For point 5, the initial commit comment is
> 
>      A very simple dynamic translator built on Vex, for the purpose of
>      debugging Vex using the binary-search-switchback technique
> 
> The Makefile refers to the ppc static library, so needs modifying to work on any 
> other platform.


Yes, I hacked that like so

all: switchback.c linker.c linker.h
	gcc -m32 -Wall -O -g -o switchback switchback.c linker.c \
		../libvex_x86_linux.a

and then you run into compiler errors related to the idiom recovery change which 
was added in 2019 in 558f5e9517a4. Clearly, switchback hasn't been used since.

> Maybe all these files should be in an "attic" directly with some text saying 
> that they are mostly forgotten.

I'd say: sometimes you just have to let go. The code base is 20+ years old, 
there are loads of BZs to fix and things that could be improved. Keeping and 
maintaining some cruft .... it's probably not a worthy endeavour.

> Back in "useful",
> 
> Is Makefile-vex any use? 

No. Makefile-vex simply invokes  ../Makefile-gcc to build the library. And 
Makefile-gcc is still there.

Cheers,

   Florian