Re: [PATCH] mips: Add appropriate linker flags when compiling with -static-pie

[Jeff Law <jeffreyalaw@gmail.com>]

On 9/25/22 09:49, linted via Gcc-patches wrote:
> Hello,
> I'm just checking to see if anyone has had a chance to look at this.
>
> Thank you
>
> On Wed, Sep 14, 2022 at 2:09 PM linted <linted90@gmail.com> wrote:
>
>> Hello,
>>
>> This patch fixes missing flags when compiling with -static-pie on mips. I
>> made these modifications based on the previously submitted static pie patch
>> for arm as well as the working code for aarch64.
>>
>> I tested with a host of mips-elf and checked with mips-sim. This patch was
>> also tested and used with uclibc-ng to generate static pie elfs.
>>
>> This is my first patch for gcc, so please let me know if there is anything
>> I missed.
>>
>>
>>
>> Signed-off-by: linted <linted@users.noreply.github.com>
>> ---
>>   gcc/config/mips/gnu-user.h | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/gcc/config/mips/gnu-user.h b/gcc/config/mips/gnu-user.h
>> index 6aad7192e69..b1c665b7f37 100644
>> --- a/gcc/config/mips/gnu-user.h
>> +++ b/gcc/config/mips/gnu-user.h
>> @@ -56,11 +56,12 @@ along with GCC; see the file COPYING3.  If not see
>>   #define GNU_USER_TARGET_LINK_SPEC "\
>>     %{G*} %{EB} %{EL} %{mips*} %{shared} \
>>     %{!shared: \
>> -    %{!static: \
>> +    %{!static:%{!static-pie: \
>>         %{rdynamic:-export-dynamic} \
>>         %{mabi=n32: -dynamic-linker " GNU_USER_DYNAMIC_LINKERN32 "} \
>>         %{mabi=64: -dynamic-linker " GNU_USER_DYNAMIC_LINKER64 "} \
>> -      %{mabi=32: -dynamic-linker " GNU_USER_DYNAMIC_LINKER32 "}} \
>> +      %{mabi=32: -dynamic-linker " GNU_USER_DYNAMIC_LINKER32 "}}} \
>> +    %{static-pie:-Bstatic -pie --no-dynamic-linker -z text} \
>>       %{static}} \

This is a bit out of my usual areas of expertise.  But what I find odd 
here is that for -static we essentially do nothing, but for -static-pie 
we need "-Bstatic -pie --no-dynamic-linker -z text".    Is the -Bstatic 
really needed for static-pie  And if it is, then wouldn't it be needed 
for -static as well?    If you look carefully at aarch64, you'll see it 
includes -Bstatic for -static.


Jeff