Re: [PATCH] arm: Allow to override location of .gnu.sgstubs section

[Torbjorn SVENSSON <torbjorn.svensson@foss.st.com>]

Hi Christophe,

On 2022-10-19 11:52, Christophe Lyon wrote:
> Hi Torbjörn,
> 
> This looks like a nice improvement to me ;-)
> 
> On 10/19/22 11:42, Torbjörn SVENSSON via Gcc-patches wrote:
>> Depending on the DejaGNU board definition, the .gnu.sgstubs section
>> might be placed on different locations in order to suite the target.
> typo: suite -> suit
> 
>> With this patch, the start location of the section is overrideable
>> from the board definition with the fallback of the previously
>> hardcoded location.
>>
>> gcc/testsuite/ChangeLog:
>>
>>     * gcc.target/arm/cmse/bitfield-1.c: Use overridable location.
>>     * gcc.target/arm/cmse/bitfield-2.c: Likewise.
>>     * gcc.target/arm/cmse/bitfield-3.c: Likewise.
>>     * gcc.target/arm/cmse/cmse-20.c: Likewise.
>>     * gcc.target/arm/cmse/struct-1.c: Likewise.
>>     * gcc.target/arm/cmse/cmse.exp (cmse_sgstubs): New.
>>
>> Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>
>> ---
>>   gcc/testsuite/gcc.target/arm/cmse/bitfield-1.c |  2 +-
>>   gcc/testsuite/gcc.target/arm/cmse/bitfield-2.c |  2 +-
>>   gcc/testsuite/gcc.target/arm/cmse/bitfield-3.c |  2 +-
>>   gcc/testsuite/gcc.target/arm/cmse/cmse-20.c    |  2 +-
>>   gcc/testsuite/gcc.target/arm/cmse/cmse.exp     | 11 +++++++++++
>>   gcc/testsuite/gcc.target/arm/cmse/struct-1.c   |  2 +-
>>   6 files changed, 16 insertions(+), 5 deletions(-)
>>
>> diff --git a/gcc/testsuite/gcc.target/arm/cmse/bitfield-1.c 
>> b/gcc/testsuite/gcc.target/arm/cmse/bitfield-1.c
>> index 5685f744435..c1221bef29f 100644
>> --- a/gcc/testsuite/gcc.target/arm/cmse/bitfield-1.c
>> +++ b/gcc/testsuite/gcc.target/arm/cmse/bitfield-1.c
>> @@ -1,5 +1,5 @@
>>   /* This test is executed only if the execution engine supports CMSE 
>> instructions.  */
>> -/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=0x00400000" } */
>> +/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=[cmse_sgstubs]" } */
>>   typedef struct
>>   {
>> diff --git a/gcc/testsuite/gcc.target/arm/cmse/bitfield-2.c 
>> b/gcc/testsuite/gcc.target/arm/cmse/bitfield-2.c
>> index 7a794d44644..79e9a3efc93 100644
>> --- a/gcc/testsuite/gcc.target/arm/cmse/bitfield-2.c
>> +++ b/gcc/testsuite/gcc.target/arm/cmse/bitfield-2.c
>> @@ -1,5 +1,5 @@
>>   /* This test is executed only if the execution engine supports CMSE 
>> instructions.  */
>> -/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=0x00400000" } */
>> +/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=[cmse_sgstubs]" } */
>>   typedef struct
>>   {
>> diff --git a/gcc/testsuite/gcc.target/arm/cmse/bitfield-3.c 
>> b/gcc/testsuite/gcc.target/arm/cmse/bitfield-3.c
>> index 5875f8dff48..d621a802ee1 100644
>> --- a/gcc/testsuite/gcc.target/arm/cmse/bitfield-3.c
>> +++ b/gcc/testsuite/gcc.target/arm/cmse/bitfield-3.c
>> @@ -1,5 +1,5 @@
>>   /* This test is executed only if the execution engine supports CMSE 
>> instructions.  */
>> -/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=0x00400000" } */
>> +/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=[cmse_sgstubs]" } */
>>   typedef struct
>>   {
>> diff --git a/gcc/testsuite/gcc.target/arm/cmse/cmse-20.c 
>> b/gcc/testsuite/gcc.target/arm/cmse/cmse-20.c
>> index 08e89bff637..bbea9358870 100644
>> --- a/gcc/testsuite/gcc.target/arm/cmse/cmse-20.c
>> +++ b/gcc/testsuite/gcc.target/arm/cmse/cmse-20.c
>> @@ -1,5 +1,5 @@
>>   /* This test is executed only if the execution engine supports CMSE 
>> instructions.  */
>> -/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=0x00400000" } */
>> +/* { dg-options "--save-temps -mcmse 
>> -Wl,--section-start,.gnu.sgstubs=[cmse_sgstubs]" } */
>>   #include <arm_cmse.h>
>>   #include <stdlib.h>
>> diff --git a/gcc/testsuite/gcc.target/arm/cmse/cmse.exp 
>> b/gcc/testsuite/gcc.target/arm/cmse/cmse.exp
>> index 436dd71ef89..1df5d56c6d5 100644
>> --- a/gcc/testsuite/gcc.target/arm/cmse/cmse.exp
>> +++ b/gcc/testsuite/gcc.target/arm/cmse/cmse.exp
>> @@ -44,6 +44,17 @@ if {[is-effective-target arm_cmse_hw]} then {
>>   set saved-lto_torture_options ${LTO_TORTURE_OPTIONS}
>>   set LTO_TORTURE_OPTIONS ""
>> +# Return the start address of the .gnu.sgstubs section.
>> +proc cmse_sgstubs {} {
>> +    # Allow to override the location of .gnu.sgstubs section.
>> +    set tboard [target_info name]
>> +    if {[board_info $tboard exists cmse_sgstubs]} {
>> +    return [board_info $tboard cmse_sgstubs]
>> +    }
>> +
>> +    return "0x00400000"
>> +}
>> +
> 
> I am not sure if/where this new cmse_sgstubs target-board property needs 
> to be documented?

I'm not sure either. Everytime I need to do something with the 
target-board properties, I just look at other examples in the tree and 
replicate what they do.
I'm also not sure if "cmse_sgstubs" is a good name, but I was unable to 
come up with a more meaningful name that was not a mile long... If there 
is any sugession on a better name, please speak up! :)

Kind regards,
Torbjörn