llvm dev - Dec 2019 - How to generate a .ll file with functions' parameter names

Hi all,
I'm trying to obtain a .ll with parameters name for every function. My
simple c C is the following:

int sum(int a, int b) {
return a+b;
}

int main() {
sum(1,2);
}

I obtain the .ll with the following commands:

clang -emit-llvm sum.c -c
llvm-dis-7 sum.bc

The obtained .ll is:

cat sum.ll
; ModuleID = 'sum.bc'
source_filename = "sum.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-pc-linux-gnu"

; Function Attrs: noinline nounwind optnone uwtable
define i32 @sum(i32, i32) #0 {
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  store i32 %0, i32* %3, align 4
  store i32 %1, i32* %4, align 4
  %5 = load i32, i32* %3, align 4
  %6 = load i32, i32* %4, align 4
  %7 = add nsw i32 %5, %6
  ret i32 %7
}

; Function Attrs: noinline nounwind optnone uwtable
define i32 @main() #0 {
  %1 = call i32 @sum(i32 1, i32 2)
  ret i32 0
}

attributes #0 = { noinline nounwind optnone uwtable
"correctly-rounded-divide-sqrt-fp-math"="false"
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-jump-tables"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"no-trapping-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }

!llvm.module.flags = !{!0}
!llvm.ident = !{!1}

!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{!"clang version 6.0.1-svn334776-1~exp1~20190309042703.125
(branches/release_60)"}

Could you tell me why I don't see a and b parameters for the sum function?

Thanks
Alberto
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Hi Alberto,

Variable names in LLVM IR are meaningless and only used for debugging.
However, if you want to preserve the variable name, you can use
`-fno-discard-value-names` option.

Regards,
Hideto

2019年12月8日(日) 17:38 Alberto Barbaro via llvm-dev <llvm-dev at
lists.llvm.org>:
> Hi all,
> I'm trying to obtain a .ll with parameters name for every function. My
> simple c C is the following:
>
> int sum(int a, int b) {
> return a+b;
> }
>
> int main() {
> sum(1,2);
> }
>
> I obtain the .ll with the following commands:
>
> clang -emit-llvm sum.c -c
> llvm-dis-7 sum.bc
>
> The obtained .ll is:
>
> cat sum.ll
> ; ModuleID = 'sum.bc'
> source_filename = "sum.c"
> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
> target triple = "x86_64-pc-linux-gnu"
>
> ; Function Attrs: noinline nounwind optnone uwtable
> define i32 @sum(i32, i32) #0 {
>   %3 = alloca i32, align 4
>   %4 = alloca i32, align 4
>   store i32 %0, i32* %3, align 4
>   store i32 %1, i32* %4, align 4
>   %5 = load i32, i32* %3, align 4
>   %6 = load i32, i32* %4, align 4
>   %7 = add nsw i32 %5, %6
>   ret i32 %7
> }
>
> ; Function Attrs: noinline nounwind optnone uwtable
> define i32 @main() #0 {
>   %1 = call i32 @sum(i32 1, i32 2)
>   ret i32 0
> }
>
> attributes #0 = { noinline nounwind optnone uwtable
> "correctly-rounded-divide-sqrt-fp-math"="false"
> "disable-tail-calls"="false"
"less-precise-fpmad"="false"
> "no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
> "no-infs-fp-math"="false"
"no-jump-tables"="false"
> "no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
> "no-trapping-math"="false"
"stack-protector-buffer-size"="8"
> "target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
> "unsafe-fp-math"="false"
"use-soft-float"="false" }
>
> !llvm.module.flags = !{!0}
> !llvm.ident = !{!1}
>
> !0 = !{i32 1, !"wchar_size", i32 4}
> !1 = !{!"clang version 6.0.1-svn334776-1~exp1~20190309042703.125
> (branches/release_60)"}
>
> Could you tell me why I don't see a and b parameters for the sum
function?
>
> Thanks
> Alberto
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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Hi Hideto,
thanks for your answer. Unfortunately I'm still using llvm 6.0 and in
llvm-dis I don't see that option. I tried reading the full list of options
but I didn't see an alternative.

Do you have any suggestions?

Thanks
Alberto

Il giorno dom 8 dic 2019 alle ore 08:50 Hideto Ueno <
uenoku.tokotoko at gmail.com> ha scritto:
> Hi Alberto,
>
> Variable names in LLVM IR are meaningless and only used for debugging.
> However, if you want to preserve the variable name, you can use
> `-fno-discard-value-names` option.
>
> Regards,
> Hideto
>
> 2019年12月8日(日) 17:38 Alberto Barbaro via llvm-dev <llvm-dev at
lists.llvm.org
> >:
>
>> Hi all,
>> I'm trying to obtain a .ll with parameters name for every function.
My
>> simple c C is the following:
>>
>> int sum(int a, int b) {
>> return a+b;
>> }
>>
>> int main() {
>> sum(1,2);
>> }
>>
>> I obtain the .ll with the following commands:
>>
>> clang -emit-llvm sum.c -c
>> llvm-dis-7 sum.bc
>>
>> The obtained .ll is:
>>
>> cat sum.ll
>> ; ModuleID = 'sum.bc'
>> source_filename = "sum.c"
>> target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>> target triple = "x86_64-pc-linux-gnu"
>>
>> ; Function Attrs: noinline nounwind optnone uwtable
>> define i32 @sum(i32, i32) #0 {
>>   %3 = alloca i32, align 4
>>   %4 = alloca i32, align 4
>>   store i32 %0, i32* %3, align 4
>>   store i32 %1, i32* %4, align 4
>>   %5 = load i32, i32* %3, align 4
>>   %6 = load i32, i32* %4, align 4
>>   %7 = add nsw i32 %5, %6
>>   ret i32 %7
>> }
>>
>> ; Function Attrs: noinline nounwind optnone uwtable
>> define i32 @main() #0 {
>>   %1 = call i32 @sum(i32 1, i32 2)
>>   ret i32 0
>> }
>>
>> attributes #0 = { noinline nounwind optnone uwtable
>> "correctly-rounded-divide-sqrt-fp-math"="false"
>> "disable-tail-calls"="false"
"less-precise-fpmad"="false"
>> "no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
>> "no-infs-fp-math"="false"
"no-jump-tables"="false"
>> "no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
>> "no-trapping-math"="false"
"stack-protector-buffer-size"="8"
>> "target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
>> "unsafe-fp-math"="false"
"use-soft-float"="false" }
>>
>> !llvm.module.flags = !{!0}
>> !llvm.ident = !{!1}
>>
>> !0 = !{i32 1, !"wchar_size", i32 4}
>> !1 = !{!"clang version 6.0.1-svn334776-1~exp1~20190309042703.125
>> (branches/release_60)"}
>>
>> Could you tell me why I don't see a and b parameters for the sum
function?
>>
>> Thanks
>> Alberto
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
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