RE: [PATCH 3/9] Hexagon (target/hexagon) Make generators object oriented - gen_helper_protos

[<ltaylorsimpson@gmail.com>]

> -----Original Message-----
> From: Brian Cain <bcain@quicinc.com>
> Sent: Monday, December 4, 2023 9:46 PM
> To: Taylor Simpson <ltaylorsimpson@gmail.com>; qemu-devel@nongnu.org
> Cc: Matheus Bernardino (QUIC) <quic_mathbern@quicinc.com>; Sid
> Manning <sidneym@quicinc.com>; Marco Liebel (QUIC)
> <quic_mliebel@quicinc.com>; richard.henderson@linaro.org;
> philmd@linaro.org; ale@rev.ng; anjo@rev.ng
> Subject: RE: [PATCH 3/9] Hexagon (target/hexagon) Make generators object
> oriented - gen_helper_protos
> 
> 
> 
> > -----Original Message-----
> > From: Taylor Simpson <ltaylorsimpson@gmail.com>
> > Sent: Monday, December 4, 2023 7:53 PM
> > To: qemu-devel@nongnu.org
> > Cc: Brian Cain <bcain@quicinc.com>; Matheus Bernardino (QUIC)
> > <quic_mathbern@quicinc.com>; Sid Manning <sidneym@quicinc.com>;
> Marco
> > Liebel (QUIC) <quic_mliebel@quicinc.com>;
> > richard.henderson@linaro.org; philmd@linaro.org; ale@rev.ng;
> > anjo@rev.ng; ltaylorsimpson@gmail.com
> > Subject: [PATCH 3/9] Hexagon (target/hexagon) Make generators object
> > oriented - gen_helper_protos
> >
> > Signed-off-by: Taylor Simpson <ltaylorsimpson@gmail.com>
> > ---
> >  target/hexagon/gen_helper_protos.py | 184 ++++++++--------------------
> >  target/hexagon/hex_common.py        |  15 +--
> >  2 files changed, 55 insertions(+), 144 deletions(-)
> >
> > diff --git a/target/hexagon/gen_helper_protos.py
> > b/target/hexagon/gen_helper_protos.py
> > index 131043795a..9277199e1d 100755
> > --- a/target/hexagon/gen_helper_protos.py
> > +++ b/target/hexagon/gen_helper_protos.py
> >  ##
> >  ## Generate the DEF_HELPER prototype for an instruction
> >  ##     For A2_add: Rd32=add(Rs32,Rt32)
> > @@ -65,116 +32,62 @@ def gen_helper_prototype(f, tag, tagregs,
> tagimms):
> >      regs = tagregs[tag]
> >      imms = tagimms[tag]
> >
> > -    numresults = 0
> > +    ## If there is a scalar result, it is the return type
> > +    return_type = ""
> 
> Should we use `return_type = None` here?
> 
> >      numscalarresults = 0
> > -    numscalarreadwrite = 0
> >      for regtype, regid in regs:
> > -        if hex_common.is_written(regid):
> > -            numresults += 1
> > -            if hex_common.is_scalar_reg(regtype):
> > +        reg = hex_common.get_register(tag, regtype, regid)
> > +        if reg.is_written() and reg.is_scalar_reg():
> > +                return_type = reg.helper_proto_type()
> >                  numscalarresults += 1
> > -        if hex_common.is_readwrite(regid):
> > -            if hex_common.is_scalar_reg(regtype):
> > -                numscalarreadwrite += 1
> > +    if numscalarresults == 0:
> > +        return_type = "void"
> 
> Should we use `return_type = None` here?

I don't see a point of setting it to None.  By the time it gets to the use below, it will definitely have a value.  We could initialize it to void instead of "" and skip this check.


> > +
> > +    ## Other stuff the helper might need
> > +    if hex_common.need_pkt_has_multi_cof(tag):
> > +        declared.append("i32")
> > +    if hex_common.need_pkt_need_commit(tag):
> > +        declared.append("i32")
> > +    if hex_common.need_PC(tag):
> > +        declared.append("i32")
> > +    if hex_common.need_next_PC(tag):
> > +        declared.append("i32")
> > +    if hex_common.need_slot(tag):
> > +        declared.append("i32")
> > +    if hex_common.need_part1(tag):
> > +        declared.append("i32")
> 
> What do you think of this instead?  The delta below is on top of this patch.
> 
> --- a/target/hexagon/gen_helper_protos.py
> +++ b/target/hexagon/gen_helper_protos.py
> @@ -73,18 +73,9 @@ def gen_helper_prototype(f, tag, tagregs, tagimms):
>          declared.append("s32")
> 
>      ## Other stuff the helper might need
> -    if hex_common.need_pkt_has_multi_cof(tag):
> -        declared.append("i32")
> -    if hex_common.need_pkt_need_commit(tag):
> -        declared.append("i32")
> -    if hex_common.need_PC(tag):
> -        declared.append("i32")
> -    if hex_common.need_next_PC(tag):
> -        declared.append("i32")
> -    if hex_common.need_slot(tag):
> -        declared.append("i32")
> -    if hex_common.need_part1(tag):
> -        declared.append("i32")
> +    for stuff in hex_common.other_stuff:
> +        if stuff(tag):
> +            declared.append('i32')
> 
>      arguments = ", ".join(declared)
>      f.write(f"DEF_HELPER_{len(declared) - 1}({tag}, {arguments})\n") diff --git
> a/target/hexagon/gen_tcg_funcs.py b/target/hexagon/gen_tcg_funcs.py
> index 8c2bc03c10..cb02d91886 100755
> --- a/target/hexagon/gen_tcg_funcs.py
> +++ b/target/hexagon/gen_tcg_funcs.py
> @@ -109,18 +109,9 @@ def gen_tcg_func(f, tag, regs, imms):
> 
> declared.append(f"tcg_constant_tl({hex_common.imm_name(immlett)})")
> 
>          ## Other stuff the helper might need
> -        if hex_common.need_pkt_has_multi_cof(tag):
> -            declared.append("tcg_constant_tl(ctx->pkt->pkt_has_multi_cof)")
> -        if hex_common.need_pkt_need_commit(tag):
> -            declared.append("tcg_constant_tl(ctx->need_commit)")
> -        if hex_common.need_PC(tag):
> -            declared.append("tcg_constant_tl(ctx->pkt->pc)")
> -        if hex_common.need_next_PC(tag):
> -            declared.append("tcg_constant_tl(ctx->next_PC)")
> -        if hex_common.need_slot(tag):
> -            declared.append("gen_slotval(ctx)")
> -        if hex_common.need_part1(tag):
> -            declared.append("tcg_constant_tl(insn->part1)")
> +        for stuff, text in hex_common.other_stuff:
> +            if stuff(tag):
> +                declared.append(text)
> 
>          arguments = ", ".join(declared)
>          f.write(f"    gen_helper_{tag}({arguments});\n")
> diff --git a/target/hexagon/hex_common.py
> b/target/hexagon/hex_common.py index 90d61a1b16..954532921d 100755
> --- a/target/hexagon/hex_common.py
> +++ b/target/hexagon/hex_common.py
> @@ -1028,3 +1028,13 @@ def get_register(tag, regtype, regid):
>          return registers[f"{regtype}{regid}"]
>      else:
>          return new_registers[f"{regtype}{regid}"]
> +
> +
> +other_stuff = {
> +    need_pkt_has_multi_cof: "tcg_constant_tl(ctx->pkt-
> >pkt_has_multi_cof)",
> +    need_pkt_need_commit: "tcg_constant_tl(ctx->need_commit)",
> +    need_PC: "tcg_constant_tl(ctx->pkt->pc)",
> +    need_next_PC: "tcg_constant_tl(ctx->next_PC)",
> +    need_slot: "gen_slotval(ctx)",
> +    need_part1: "tcg_constant_tl(insn->part1)", }

Great idea to centralize these in hex_common.  There are three parts though.  There's the actual helper argument in gen_hepler_funcs.py.  I'll think about how best to cover the 3 parts.  Let me know if you have ideas as well.

Thanks,
Taylor