[Buildroot] [PATCH 1/1] package/cmocka: don't allow building for Thumb1

[Buildroot] [PATCH 1/1] package/cmocka: don't allow building for Thumb1

[Joel Carlson]

The cmocka package checks if a toolchain supports the
-fstack-clash-protection compiler flag, and if it does automatically
uses it. That flag is not supported by GCC for Thumb1 builds (at least
as of both GCC 11 and GCC 12). So disallow building cmocka for Thumb1.
Building for ARM or Thumb2 is fine.

As an example in GCC 12.2.0, within the file gcc/config/arm/arm.cc, the
error occurs in the thumb1_expand_prologue() call:

    /* If we have a frame, then do stack checking.  FIXME: not implemented.  */
    if ((flag_stack_check == STATIC_BUILTIN_STACK_CHECK
         || flag_stack_clash_protection)
        && size)
      sorry ("%<-fstack-check=specific%> for Thumb-1");

An example build error output:
/tmp/instance-7/output-1/build/cmocka-1.1.5/src/cmocka.c: In function 'c_strmatch.part.0':
/tmp/instance-7/output-1/build/cmocka-1.1.5/src/cmocka.c:539:1: sorry, unimplemented: '-fstack-check=specific' for Thumb-1
  539 | }
        | ^

Fixes:
http://autobuild.buildroot.net/results/4044b3a71d3130d934c7a7c0c5badfabb2a97030/

Signed-off-by: Joel Carlson <JoelsonCarl@gmail.com>
---
 package/cmocka/Config.in | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/package/cmocka/Config.in b/package/cmocka/Config.in
index cf49d0f6be..6cadaa616a 100644
--- a/package/cmocka/Config.in
+++ b/package/cmocka/Config.in
@@ -1,6 +1,7 @@
 config BR2_PACKAGE_CMOCKA
 	bool cmocka
 	depends on !BR2_STATIC_LIBS
+	depends on !BR2_ARM_INSTRUCTIONS_THUMB
 	help
 	  cmocka is an elegant unit testing framework for C with support
 	  for mock objects. It only requires the standard C library,
@@ -11,5 +12,5 @@ config BR2_PACKAGE_CMOCKA
 
 	  https://cmocka.org
 
-comment "cmocka needs a toolchain w/ dynamic library"
-	depends on BR2_STATIC_LIBS
+comment "cmocka needs a toolchain w/ dynamic library, and can't be built for Thumb1"
+	depends on BR2_STATIC_LIBS || BR2_ARM_INSTRUCTIONS_THUMB
-- 
2.34.1

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Re: [Buildroot] [PATCH 1/1] package/cmocka: don't allow building for Thumb1

[Arnout Vandecappelle]

On 02/01/2023 08:15, Joel Carlson wrote:
> The cmocka package checks if a toolchain supports the
> -fstack-clash-protection compiler flag, and if it does automatically
> uses it. That flag is not supported by GCC for Thumb1 builds (at least
> as of both GCC 11 and GCC 12). So disallow building cmocka for Thumb1.
> Building for ARM or Thumb2 is fine.
> 
> As an example in GCC 12.2.0, within the file gcc/config/arm/arm.cc, the
> error occurs in the thumb1_expand_prologue() call:
> 
>      /* If we have a frame, then do stack checking.  FIXME: not implemented.  */
>      if ((flag_stack_check == STATIC_BUILTIN_STACK_CHECK
>           || flag_stack_clash_protection)
>          && size)
>        sorry ("%<-fstack-check=specific%> for Thumb-1");
> 
> An example build error output:
> /tmp/instance-7/output-1/build/cmocka-1.1.5/src/cmocka.c: In function 'c_strmatch.part.0':
> /tmp/instance-7/output-1/build/cmocka-1.1.5/src/cmocka.c:539:1: sorry, unimplemented: '-fstack-check=specific' for Thumb-1
>    539 | }
>          | ^
> 
> Fixes:
> http://autobuild.buildroot.net/results/4044b3a71d3130d934c7a7c0c5badfabb2a97030/

  Instead of adding an arch exception, have you tried (conditionally) adding 
-DWITH_STACK_CLASH_PROTECTION=OFF to CMOCKA_CONFIGURE_OPTS? I think that that 
should bypass the check.

  Regards,
  Arnout

> 
> Signed-off-by: Joel Carlson <JoelsonCarl@gmail.com>
> ---
>   package/cmocka/Config.in | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/package/cmocka/Config.in b/package/cmocka/Config.in
> index cf49d0f6be..6cadaa616a 100644
> --- a/package/cmocka/Config.in
> +++ b/package/cmocka/Config.in
> @@ -1,6 +1,7 @@
>   config BR2_PACKAGE_CMOCKA
>   	bool cmocka
>   	depends on !BR2_STATIC_LIBS
> +	depends on !BR2_ARM_INSTRUCTIONS_THUMB
>   	help
>   	  cmocka is an elegant unit testing framework for C with support
>   	  for mock objects. It only requires the standard C library,
> @@ -11,5 +12,5 @@ config BR2_PACKAGE_CMOCKA
>   
>   	  https://cmocka.org
>   
> -comment "cmocka needs a toolchain w/ dynamic library"
> -	depends on BR2_STATIC_LIBS
> +comment "cmocka needs a toolchain w/ dynamic library, and can't be built for Thumb1"
> +	depends on BR2_STATIC_LIBS || BR2_ARM_INSTRUCTIONS_THUMB
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Re: [Buildroot] [PATCH 1/1] package/cmocka: don't allow building for Thumb1

[Thomas Petazzoni via buildroot]

On Thu, 9 Mar 2023 22:54:27 +0100
Arnout Vandecappelle <arnout@mind.be> wrote:

>   Instead of adding an arch exception, have you tried (conditionally) adding 
> -DWITH_STACK_CLASH_PROTECTION=OFF to CMOCKA_CONFIGURE_OPTS? I think that that 
> should bypass the check.

It works!

So I applied Joel's patch but essentially rewrote it (and its commit
message) to use the solution proposed by Arnout.

Thanks!

Thomas
-- 
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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