xen-tools compilation errors with GCC 11

xen-tools compilation errors with GCC 11

[Diego Sueiro]

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Hello,

We identified compilation errors for xen-tools (4.14 and 4.15) with GCC 11.1 due to `-Werror=vla-parameter`.

There are a couple of source files with similar errors like this:
```
linux.c:164:50: error: argument 7 of type 'const xen_pfn_t[]' {aka 'const long unsigned int[]'} declared as an ordinary array [-Werror=vla-parameter]
  164 |                                  const xen_pfn_t arr[/*num*/], int err[/*num*/])
      |                                  ~~~~~~~~~~~~~~~~^~~~~~~~~~~~
```

The quick fix for is to have the following:
```
diff --git a/recipes-extended/xen/xen-tools.inc b/recipes-extended/xen/xen-tools.inc
index 3560e79..5a054af 100644
--- a/recipes-extended/xen/xen-tools.inc
+++ b/recipes-extended/xen/xen-tools.inc
@@ -725,9 +725,11 @@ do_configure() {
     do_configure_common
}

+EXTRA_CFLAGS_XEN_TOOLS_append = " -Wno-vla-parameter"
+
do_compile() {
     cd ${S}
-    oe_runmake tools PYTHON="${PYTHON}"
+    oe_runmake tools EXTRA_CFLAGS_XEN_TOOLS="${EXTRA_CFLAGS_XEN_TOOLS}" PYTHON="${PYTHON}"
}

do_install() {
```

I'd like to know if this is an acceptable solution or if you have any other suggestions other than fixing the actual code
since this might take some time and I think that the Xen community will be looking at this soon.

Cheers,

--
Diego Sueiro



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Re: xen-tools compilation errors with GCC 11

[Bruce Ashfield]

On Thu, May 6, 2021 at 2:01 AM Diego Sueiro <Diego.Sueiro@arm.com> wrote:
>
> Hello,
>
>
>
> We identified compilation errors for xen-tools (4.14 and 4.15) with GCC 11.1 due to `-Werror=vla-parameter`.
>
>
>
> There are a couple of source files with similar errors like this:
>
> ```
>
> linux.c:164:50: error: argument 7 of type 'const xen_pfn_t[]' {aka 'const long unsigned int[]'} declared as an ordinary array [-Werror=vla-parameter]
>
>   164 |                                  const xen_pfn_t arr[/*num*/], int err[/*num*/])
>
>       |                                  ~~~~~~~~~~~~~~~~^~~~~~~~~~~~
>
> ```
>
>
>
> The quick fix for is to have the following:
>
> ```
>
> diff --git a/recipes-extended/xen/xen-tools.inc b/recipes-extended/xen/xen-tools.inc
>
> index 3560e79..5a054af 100644
>
> --- a/recipes-extended/xen/xen-tools.inc
>
> +++ b/recipes-extended/xen/xen-tools.inc
>
> @@ -725,9 +725,11 @@ do_configure() {
>
>      do_configure_common
>
> }
>
>
>
> +EXTRA_CFLAGS_XEN_TOOLS_append = " -Wno-vla-parameter"
>
> +
>
> do_compile() {
>
>      cd ${S}
>
> -    oe_runmake tools PYTHON="${PYTHON}"
>
> +    oe_runmake tools EXTRA_CFLAGS_XEN_TOOLS="${EXTRA_CFLAGS_XEN_TOOLS}" PYTHON="${PYTHON}"
>
> }
>
>
>
> do_install() {
>
> ```
>
>
>
> I’d like to know if this is an acceptable solution or if you have any other suggestions other than fixing the actual code
>
> since this might take some time and I think that the Xen community will be looking at this soon.
>

I'm ok with the workaround. The code hasn't changed, and we've lived
with it so far, so I'm not really concerned at the technical level
about the warning.

And I'd rather no one spend the time to do a fix that might be
different than the eventual upstream Xen solution.

Bruce

>
>
> Cheers,
>
>
>
> --
> Diego Sueiro
>
>



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