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* [musl] [PATCH] mips: use `jr $ra` instead of `j $ra` to work around an LLVM assembler bug
@ 2024-09-18  1:18 Alex Rønne Petersen
  2024-10-22 22:58 ` Rich Felker
  0 siblings, 1 reply; 3+ messages in thread
From: Alex Rønne Petersen @ 2024-09-18  1:18 UTC (permalink / raw)
  To: musl; +Cc: Alex Rønne Petersen

Details here: https://github.com/llvm/llvm-project/issues/107460

This patch works around the bug by just using the `jr $ra` form, which also more
precisely indicates the encoding intent anyway.
---
 crt/mips/crtn.s   | 4 ++--
 crt/mips64/crtn.s | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/crt/mips/crtn.s b/crt/mips/crtn.s
index 506a04b7..92eb3d0e 100644
--- a/crt/mips/crtn.s
+++ b/crt/mips/crtn.s
@@ -3,11 +3,11 @@
 .section .init
 	lw $gp,24($sp)
 	lw $ra,28($sp)
-	j $ra
+	jr $ra
 	addu $sp,$sp,32
 
 .section .fini
 	lw $gp,24($sp)
 	lw $ra,28($sp)
-	j $ra
+	jr $ra
 	addu $sp,$sp,32
diff --git a/crt/mips64/crtn.s b/crt/mips64/crtn.s
index f3930b24..8f090ed3 100644
--- a/crt/mips64/crtn.s
+++ b/crt/mips64/crtn.s
@@ -3,11 +3,11 @@
 .section .init
 	ld $gp,16($sp)
 	ld $ra,24($sp)
-	j $ra
+	jr $ra
 	daddu $sp,$sp,32
 
 .section .fini
 	ld $gp,16($sp)
 	ld $ra,24($sp)
-	j $ra
+	jr $ra
 	daddu $sp,$sp,32
-- 
2.40.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [musl] [PATCH] mips: use `jr $ra` instead of `j $ra` to work around an LLVM assembler bug
  2024-09-18  1:18 [musl] [PATCH] mips: use `jr $ra` instead of `j $ra` to work around an LLVM assembler bug Alex Rønne Petersen
@ 2024-10-22 22:58 ` Rich Felker
  2024-10-26 20:13   ` Alex Rønne Petersen
  0 siblings, 1 reply; 3+ messages in thread
From: Rich Felker @ 2024-10-22 22:58 UTC (permalink / raw)
  To: Alex Rønne Petersen; +Cc: musl

On Wed, Sep 18, 2024 at 03:18:42AM +0200, Alex Rønne Petersen wrote:
> Details here: https://github.com/llvm/llvm-project/issues/107460
> 
> This patch works around the bug by just using the `jr $ra` form, which also more
> precisely indicates the encoding intent anyway.
> ---
>  crt/mips/crtn.s   | 4 ++--
>  crt/mips64/crtn.s | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/crt/mips/crtn.s b/crt/mips/crtn.s
> index 506a04b7..92eb3d0e 100644
> --- a/crt/mips/crtn.s
> +++ b/crt/mips/crtn.s
> @@ -3,11 +3,11 @@
>  .section .init
>  	lw $gp,24($sp)
>  	lw $ra,28($sp)
> -	j $ra
> +	jr $ra
>  	addu $sp,$sp,32
>  
>  .section .fini
>  	lw $gp,24($sp)
>  	lw $ra,28($sp)
> -	j $ra
> +	jr $ra
>  	addu $sp,$sp,32
> diff --git a/crt/mips64/crtn.s b/crt/mips64/crtn.s
> index f3930b24..8f090ed3 100644
> --- a/crt/mips64/crtn.s
> +++ b/crt/mips64/crtn.s
> @@ -3,11 +3,11 @@
>  .section .init
>  	ld $gp,16($sp)
>  	ld $ra,24($sp)
> -	j $ra
> +	jr $ra
>  	daddu $sp,$sp,32
>  
>  .section .fini
>  	ld $gp,16($sp)
>  	ld $ra,24($sp)
> -	j $ra
> +	jr $ra
>  	daddu $sp,$sp,32
> -- 
> 2.40.1

Thanks. Applying this with the same applied to mipsn32 too.

Rich

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [musl] [PATCH] mips: use `jr $ra` instead of `j $ra` to work around an LLVM assembler bug
  2024-10-22 22:58 ` Rich Felker
@ 2024-10-26 20:13   ` Alex Rønne Petersen
  0 siblings, 0 replies; 3+ messages in thread
From: Alex Rønne Petersen @ 2024-10-26 20:13 UTC (permalink / raw)
  To: Rich Felker; +Cc: musl

On Wed, Oct 23, 2024 at 12:58 AM Rich Felker <dalias@libc.org> wrote:
>
> On Wed, Sep 18, 2024 at 03:18:42AM +0200, Alex Rønne Petersen wrote:
> > Details here: https://github.com/llvm/llvm-project/issues/107460
> >
> > This patch works around the bug by just using the `jr $ra` form, which also more
> > precisely indicates the encoding intent anyway.
> > ---
> >  crt/mips/crtn.s   | 4 ++--
> >  crt/mips64/crtn.s | 4 ++--
> >  2 files changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/crt/mips/crtn.s b/crt/mips/crtn.s
> > index 506a04b7..92eb3d0e 100644
> > --- a/crt/mips/crtn.s
> > +++ b/crt/mips/crtn.s
> > @@ -3,11 +3,11 @@
> >  .section .init
> >       lw $gp,24($sp)
> >       lw $ra,28($sp)
> > -     j $ra
> > +     jr $ra
> >       addu $sp,$sp,32
> >
> >  .section .fini
> >       lw $gp,24($sp)
> >       lw $ra,28($sp)
> > -     j $ra
> > +     jr $ra
> >       addu $sp,$sp,32
> > diff --git a/crt/mips64/crtn.s b/crt/mips64/crtn.s
> > index f3930b24..8f090ed3 100644
> > --- a/crt/mips64/crtn.s
> > +++ b/crt/mips64/crtn.s
> > @@ -3,11 +3,11 @@
> >  .section .init
> >       ld $gp,16($sp)
> >       ld $ra,24($sp)
> > -     j $ra
> > +     jr $ra
> >       daddu $sp,$sp,32
> >
> >  .section .fini
> >       ld $gp,16($sp)
> >       ld $ra,24($sp)
> > -     j $ra
> > +     jr $ra
> >       daddu $sp,$sp,32
> > --
> > 2.40.1
>
> Thanks. Applying this with the same applied to mipsn32 too.

Oops, I'd completely forgotten to apply it there because we hadn't yet
imported musl's mipsn32 code in Zig. Thanks!

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2024-10-26 20:14 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2024-09-18  1:18 [musl] [PATCH] mips: use `jr $ra` instead of `j $ra` to work around an LLVM assembler bug Alex Rønne Petersen
2024-10-22 22:58 ` Rich Felker
2024-10-26 20:13   ` Alex Rønne Petersen

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