Re: [COMMITTED] bpf: disable -fstack-protector in BPF

[Jan-Benedict Glaw]

On Tue, 2023-01-17 17:25:08 +0100, Jose E. Marchesi via Gcc-patches 
 wrote:
> The stack protector is not supported in BPF.  This patch disables
> -fstack-protector in bpf-* targets, along with the emission of a note
> indicating that the feature is not supported in this platform.
[...]
> diff --git a/gcc/config/bpf/bpf.cc b/gcc/config/bpf/bpf.cc
> index 576a1fe8eab..b268801d00c 100644
> --- a/gcc/config/bpf/bpf.cc
> +++ b/gcc/config/bpf/bpf.cc
> @@ -253,6 +253,14 @@ bpf_option_override (void)
>if (bpf_has_jmp32 == -1)
>  bpf_has_jmp32 = (bpf_isa >= ISA_V3);
>  
> +  /* Disable -fstack-protector as it is not supported in BPF.  */
> +  if (flag_stack_protect)
> +{
> +  inform (input_location,
> +  "%<-fstack-protector%> does not work "
> +  " on this architecture");
> +  flag_stack_protect = 0;
> +}

Building with a recent GCC with (noticed during a -Werror build), this
results in a new warning:

[all 2023-01-27 16:26:25] ../../gcc/gcc/config/bpf/bpf.cc: In function 'void 
bpf_option_override()':
[all 2023-01-27 16:26:25] ../../gcc/gcc/config/bpf/bpf.cc:260:51: error: 
unquoted sequence of 2 consecutive space characters in format 
[-Werror=format-diag]
[all 2023-01-27 16:26:25]   260 |   "%<-fstack-protector%> does not 
work "
[all 2023-01-27 16:26:25]   |   
^~
[all 2023-01-27 16:26:25]   261 |   " on this architecture");
[all 2023-01-27 16:26:25]   |   ~~  
 
[all 2023-01-27 16:26:27] cc1plus: all warnings being treated as errors

MfG, JBG

-- 


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[COMMITTED] bpf: disable -fstack-protector in BPF

[Jose E. Marchesi via Gcc-patches]

The stack protector is not supported in BPF.  This patch disables
-fstack-protector in bpf-* targets, along with the emission of a note
indicating that the feature is not supported in this platform.

Regtested in bpf-unknown-none.

gcc/ChangeLog:

* config/bpf/bpf.cc (bpf_option_override): Disable
-fstack-protector.
---
 gcc/config/bpf/bpf.cc | 8 
 1 file changed, 8 insertions(+)

diff --git a/gcc/config/bpf/bpf.cc b/gcc/config/bpf/bpf.cc
index 576a1fe8eab..b268801d00c 100644
--- a/gcc/config/bpf/bpf.cc
+++ b/gcc/config/bpf/bpf.cc
@@ -253,6 +253,14 @@ bpf_option_override (void)
   if (bpf_has_jmp32 == -1)
 bpf_has_jmp32 = (bpf_isa >= ISA_V3);
 
+  /* Disable -fstack-protector as it is not supported in BPF.  */
+  if (flag_stack_protect)
+{
+  inform (input_location,
+  "%<-fstack-protector%> does not work "
+  " on this architecture");
+  flag_stack_protect = 0;
+}
 }
 
 #undef TARGET_OPTION_OVERRIDE
-- 
2.30.2