Re: [PATCH v2] testsuite: Only run test on target if VMA == LMA

[Richard Sandiford <richard.sandiford@arm.com>]

Torbjörn SVENSSON via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> Checking that the triplet matches arm*-*-eabi (or msp430-*-*) is not
> enough to know if the execution will enter an endless loop, or if it
> will give a meaningful result. As the execution test only work when
> VMA and LMA are equal, make sure that this condition is met.
>
> 2022-09-16  Torbjörn SVENSSON  <torbjorn.svensson@foss.st.com>
>
> gcc/testsuite/ChangeLog:
>
> 	* lib/target-supports.exp (check_effective_target_vma_equals_lma): New.
>         * c-c++-common/torture/attr-noinit-1.c: Requre VMA == LMA to run.
>         * c-c++-common/torture/attr-noinit-2.c: Likewise.
>         * c-c++-common/torture/attr-noinit-3.c: Likewise.
>         * c-c++-common/torture/attr-persistent-1.c: Likewise.
>         * c-c++-common/torture/attr-persistent-3.c: Likewise.

Looks like a nice thing to have.

Could you add an entry to doc/sourcebuild.texi too?

A couple of comments below...

> Co-Authored-By: Yvan ROUX  <yvan.roux@foss.st.com>
> Signed-off-by: Torbjörn SVENSSON  <torbjorn.svensson@foss.st.com>
> ---
>  .../c-c++-common/torture/attr-noinit-1.c      |  3 +-
>  .../c-c++-common/torture/attr-noinit-2.c      |  3 +-
>  .../c-c++-common/torture/attr-noinit-3.c      |  3 +-
>  .../c-c++-common/torture/attr-persistent-1.c  |  3 +-
>  .../c-c++-common/torture/attr-persistent-3.c  |  3 +-
>  gcc/testsuite/lib/target-supports.exp         | 49 +++++++++++++++++++
>  6 files changed, 59 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/testsuite/c-c++-common/torture/attr-noinit-1.c b/gcc/testsuite/c-c++-common/torture/attr-noinit-1.c
> index 877e7647ac9..f84eba0b649 100644
> --- a/gcc/testsuite/c-c++-common/torture/attr-noinit-1.c
> +++ b/gcc/testsuite/c-c++-common/torture/attr-noinit-1.c
> @@ -1,4 +1,5 @@
> -/* { dg-do run } */
> +/* { dg-do link } */
> +/* { dg-do run { target { vma_equals_lma } } } */
>  /* { dg-require-effective-target noinit } */
>  /* { dg-skip-if "data LMA != VMA" { msp430-*-* } { "-mlarge" } } */
>  /* { dg-options "-save-temps" } */
> diff --git a/gcc/testsuite/c-c++-common/torture/attr-noinit-2.c b/gcc/testsuite/c-c++-common/torture/attr-noinit-2.c
> index befa2a0bd52..4528b9e3cfa 100644
> --- a/gcc/testsuite/c-c++-common/torture/attr-noinit-2.c
> +++ b/gcc/testsuite/c-c++-common/torture/attr-noinit-2.c
> @@ -1,4 +1,5 @@
> -/* { dg-do run } */
> +/* { dg-do link } */
> +/* { dg-do run { target { vma_equals_lma } } } */
>  /* { dg-require-effective-target noinit } */
>  /* { dg-options "-fdata-sections -save-temps" } */
>  /* { dg-skip-if "data LMA != VMA" { msp430-*-* } { "-mlarge" } } */
> diff --git a/gcc/testsuite/c-c++-common/torture/attr-noinit-3.c b/gcc/testsuite/c-c++-common/torture/attr-noinit-3.c
> index 519e88a59a6..2f1745694c9 100644
> --- a/gcc/testsuite/c-c++-common/torture/attr-noinit-3.c
> +++ b/gcc/testsuite/c-c++-common/torture/attr-noinit-3.c
> @@ -1,4 +1,5 @@
> -/* { dg-do run } */
> +/* { dg-do link } */
> +/* { dg-do run { target { vma_equals_lma } } } */
>  /* { dg-require-effective-target noinit } */
>  /* { dg-options "-flto -save-temps" } */
>  /* { dg-skip-if "data LMA != VMA" { msp430-*-* } { "-mlarge" } } */
> diff --git a/gcc/testsuite/c-c++-common/torture/attr-persistent-1.c b/gcc/testsuite/c-c++-common/torture/attr-persistent-1.c
> index 72dc3c27192..b11a515cef8 100644
> --- a/gcc/testsuite/c-c++-common/torture/attr-persistent-1.c
> +++ b/gcc/testsuite/c-c++-common/torture/attr-persistent-1.c
> @@ -1,4 +1,5 @@
> -/* { dg-do run } */
> +/* { dg-do link } */
> +/* { dg-do run { target { vma_equals_lma } } } */
>  /* { dg-require-effective-target persistent } */
>  /* { dg-skip-if "data LMA != VMA" { msp430-*-* } { "-mlarge" } } */
>  /* { dg-options "-save-temps" } */
> diff --git a/gcc/testsuite/c-c++-common/torture/attr-persistent-3.c b/gcc/testsuite/c-c++-common/torture/attr-persistent-3.c
> index 3e4fd28618d..068a72af5c8 100644
> --- a/gcc/testsuite/c-c++-common/torture/attr-persistent-3.c
> +++ b/gcc/testsuite/c-c++-common/torture/attr-persistent-3.c
> @@ -1,4 +1,5 @@
> -/* { dg-do run } */
> +/* { dg-do link } */
> +/* { dg-do run { target { vma_equals_lma } } } */
>  /* { dg-require-effective-target persistent } */
>  /* { dg-options "-flto -save-temps" } */
>  /* { dg-skip-if "data LMA != VMA" { msp430-*-* } { "-mlarge" } } */
> diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
> index 703aba412a6..df8141a15d8 100644
> --- a/gcc/testsuite/lib/target-supports.exp
> +++ b/gcc/testsuite/lib/target-supports.exp
> @@ -370,6 +370,55 @@ proc check_weak_override_available { } {
>      return [check_weak_available]
>  }
>  
> +# Return 1 if VMA is equal to LMA for the .data section, 0
> +# otherwise.  Cache the result.
> +
> +proc check_effective_target_vma_equals_lma { } {
> +    global tool
> +
> +    return [check_cached_effective_target vma_equals_lma {
> +	set src vma_equals_lma[pid].c
> +	set exe vma_equals_lma[pid].exe
> +	verbose "check_effective_target_vma_equals_lma  compiling testfile $src" 2
> +	set f [open $src "w"]
> +	puts $f "#ifdef __cplusplus\nextern \"C\"\n#endif\n"
> +	puts $f "int foo = 42; void main() {}"
> +	close $f
> +	set lines [${tool}_target_compile $src $exe executable ""]
> +	file delete $src
> +
> +	if [string match "" $lines] then {
> +	    # No error messages
> +
> +            set objdump_name [find_binutils_prog objdump]
> +            set output [remote_exec host "$objdump_name" "--section-headers --section=.data $exe"]
> +            set output [lindex $output 1]
> +
> +            remote_file build delete $exe
> +
> +            # Example output of objdump:
> +            #vma_equals_lma9059.exe:     file format elf32-littlearm
> +            #
> +            #Sections:
> +            #Idx Name          Size      VMA       LMA       File off  Algn
> +            #  6 .data         00000558  20000000  08002658  00020000  2**3
> +            #                  CONTENTS, ALLOC, LOAD, DATA
> +
> +            # Capture LMA and VMA columns for .data section
> +            if ![ regexp "\d*\d+\s+\.data\s+\d+\s+(\d+)\s+(\d+)" $output dummy vma lma ] {

Maybe my Tcl is getting rusty, but I'm surprised this quoting works.
I'd have expected single backslashes to be interpreted as C-style
sequences (for \n etc) and so be eaten before regexp sees them.
Quoting with {...} instead of "..." would avoid that.

> +                verbose "Could not parse objdump output" 2
> +                return 0
> +            } else {
> +                return [string equal $vma $lma]
> +            }
> +	} else {
> +            remote_file build delete $exe
> +            verbose "Could not determine if VMA is equal to LMA. Assuming not equal." 2
> +            return 0
> +	}

Would it be more conservative to return 1 on failure rather than 0?
That way, a faulty test would trigger XFAILs rather than UNSUPPORTEDs,
with XFAILs being more likely to get attention.

On the other hand, I suppose we don't lose much if these tests are
run on common targets only.  So either way is OK, just asking. ;-)

Thanks,
Richard

> +    }]
> +}
> +
>  # The "noinit" attribute is only supported by some targets.
>  # This proc returns 1 if it's supported, 0 if it's not.