Re: gnatlink vs. -mthumb -march=armv7-a+simd -mfloat-abi=hard

[Sebastian Huber <sebastian.huber@embedded-brains.de>]

On 25.06.24 14:53, Sebastian Huber wrote:
> On 24.06.24 16:06, Sebastian Huber wrote:
>> On 28.04.22 10:16, Sebastian Huber wrote:
>>> Hello,
>>>
>>> I test currently the Ada support for RTEMS in GCC 12. We have a 
>>> -mthumb -march=armv7-a+simd -mfloat-abi=hard multilib for which the 
>>> Ada RTS is built like this:
>>>
>>> make[4]: Entering directory 
>>> '/tmp/sh/b-gcc-arm-rtems6/arm-rtems6/thumb/armv7-a+simd/hard/libada'
>>> make -C ../../../../.././gcc/ada "MAKEOVERRIDES=" "LDFLAGS=-mthumb 
>>> -march=armv7-a+simd -mfloat-abi=hard" "LN_S=ln -s" "SHELL=/bin/sh" 
>>> "GNATLIBFLAGS=-W -Wall -gnatpg -nostdinc -mthumb -march=armv7-a+simd 
>>> -mfloat-abi=hard" "GNATLIBCFLAGS=-g -O2 -mthumb -march=armv7-a+simd 
>>> -mfloat-abi=hard" "GNATLIBCFLAGS_FOR_C=-W -Wall -g -O2 -g -O2 
>>> -fexceptions -DIN_RTS -DHAVE_GETIPINFO  -mthumb -march=armv7-a+simd 
>>> -mfloat-abi=hard" "PICFLAG_FOR_TARGET=-fPIC" "THREAD_KIND=native" 
>>> "TRACE=no" "MULTISUBDIR=/thumb/armv7-a+simd/hard" 
>>> "libsubdir=/tmp/sh/i-arm-rtems6/lib64/gcc/arm-rtems6/12.0.1/thumb/armv7-a+simd/hard" "toolexeclibdir=/tmp/sh/i-arm-rtems6/lib64/gcc/arm-rtems6/12.0.1/thumb/armv7-a+simd/hard/adalib" "objext=.o" "prefix=/tmp/sh/i-arm-rtems6" "exeext=.exeext.should.not.be.used " 'CC=the.host.compiler.should.not.be.needed' "GCC_FOR_TARGET=/tmp/sh/b-gcc-arm-rtems6/./gcc/xgcc -B/tmp/sh/b-gcc-arm-rtems6/./gcc/ -nostdinc -B/tmp/sh/b-gcc-arm-rtems6/arm-rtems6/newlib/ -isystem /tmp/sh/b-gcc-arm-rtems6/arm-rtems6/newlib/targ-include -isystem /home/EB/sebastian_h/src/gcc/newlib/libc/include -B/tmp/sh/i-arm-rtems6/arm-rtems6/bin/ -B/tmp/sh/i-arm-rtems6/arm-rtems6/lib/ -isystem /tmp/sh/i-arm-rtems6/arm-rtems6/include -isystem /tmp/sh/i-arm-rtems6/arm-rtems6/sys-include   " "CFLAGS=-g -O2  -mthumb -march=armv7-a+simd -mfloat-abi=hard" ./bldtools/oscons/xoscons
>>>
>>> When I try to link a test application I get this error:
>>>
>>> arm-rtems7-gnatlink 
>>> /tmp/sh/b-rtems/arm/realview_pbx_a9_qemu/testsuites/ada/samples/nsecs/nsecs.ali testsuites/ada/samples/nsecs/init.o -qnolinkcmds -T linkcmds.realview_pbx_a9_qemu -Wl,--wrap=printf -Wl,--wrap=puts -Wl,--wrap=putchar -L. -lrtemscpu -lrtemsbsp -lrtemstest -qrtems -mthumb -march=armv7-a+simd -mfloat-abi=hard -mtune=cortex-a9 -Wl,--gc-sections -L/home/EB/sebastian_h/src/rtems/bsps/arm/shared/start -L/home/EB/sebastian_h/src/rtems/bsps/arm/realview-pbx-a9/start -o /tmp/sh/b-rtems/arm/realview_pbx_a9_qemu/testsuites/ada/ada_nsecs.exe
>>> /opt/rtems/7/lib/gcc/arm-rtems7/12.0.1/thumb/armv7-a+simd/hard/adainclude/s-secsta.ads:288:9: sorry, unimplemented: Thumb-1 'hard-float' VFP ABI
>>>
>>> The s-secsta.ads seems to be from the right multilib directory 
>>> (Thumb-2), however, I get a sorry message related to Thumb-1?
>>
>> I tried it again with GCC 13, but the problem still exists. I tried to 
>> use strace to get some more insights (the environment variables are 
>> partially shown):
>>
>> [pid 110912] execve("/opt/rtems-6-zynq-1/bin/arm-rtems6-gnatmake", 
>> ["/opt/rtems-6-zynq-1/bin/arm-rtems6-gnatmake", "-D", 
>> "testsuites/ada/tmtests/tm20", "-bargs", "-Mgnat_main", "-margs", 
>> "-Icpukit/include/adainclude", 
>> "-I../../../../src/rtems/cpukit/include/adainclude", 
>> "-Itestsuites/ada/support", 
>> "-I../../../../src/rtems/testsuites/ada/support", "-cargs", 
>> "-march=armv7-a", "-mthumb", "-mfpu=neon", "-mfloat-abi=hard", 
>> "-mtune=cortex-a9", "-largs", "testsuites/ada/tmtests/tm20/init.o", 
>> "-Wl,--wrap=printf", "-Wl,--wrap=puts", "-Wl,--wrap=putchar", "-L.", 
>> "-lrtemscpu", "-lrtemsbsp", "-lrtemstest", "-qrtems", 
>> "-march=armv7-a", "-mthumb", "-mfpu=neon", "-mfloat-abi=hard", 
>> "-mtune=cortex-a9", "-Wl,--gc-sections", 
>> "-L/opt/rtems-6-zynq-1/src/rtems/bsps/arm/shared/start", 
>> "-L/opt/rtems-6-zynq-1/src/rtems/bsps/arm/xilinx-zynq/start", 
>> "-margs", "-a", 
>> "/opt/rtems-6-zynq-1/src/rtems/testsuites/ada/tmtests/tm20/tm20.adb", 
>> "-o", 
>> "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/ada_tm20.exe"], [] <unfinished ...>
>>
>> [pid 110913] execve("/opt/rtems-6-zynq-1//bin/arm-rtems6-gcc", 
>> ["/opt/rtems-6-zynq-1//bin/arm-rtems6-gcc", "-march=armv7-a", 
>> "-mthumb", "-mfpu=neon", "-mfloat-abi=hard", "-mtune=cortex-a9", 
>> "-march=armv7-a", "-mthumb", "-mfpu=neon", "-mfloat-abi=hard", 
>> "-mtune=cortex-a9", "-print-multi-directory"], []) = 0
>>
>> The above call is used to get the multi-lib directory. Which yields:
>>
>> --RTS=thumb/armv7-a+simd/hard
>>
>> The flags seem to be obtained by getting all "-m" flags from the 
>> previous "-cargs" and "-largs". So, each flags appears twice.
>>
>> [pid 110914] execve("/opt/rtems-6-zynq-1//bin/arm-rtems6-gnatbind", 
>> ["/opt/rtems-6-zynq-1//bin/arm-rtems6-gnatbind", 
>> "-aO/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm20", "-Mgnat_main", "-Icpukit/include/adainclude", "-I../../../../src/rtems/cpukit/include/adainclude", "-Itestsuites/ada/support", "-I../../../../src/rtems/testsuites/ada/support", "--RTS=thumb/armv7-a+simd/hard", "-x", "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm20/tm20.ali"], []) = 0
>>
>> [pid 110915] execve("/opt/rtems-6-zynq-1//bin/arm-rtems6-gnatlink", 
>> ["/opt/rtems-6-zynq-1//bin/arm-rtems6-gnatlink", 
>> "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm20/tm20.ali", "testsuites/ada/tmtests/tm20/init.o", "-Wl,--wrap=printf", "-Wl,--wrap=puts", "-Wl,--wrap=putchar", "-L.", "-lrtemscpu", "-lrtemsbsp", "-lrtemstest", "-qrtems", "-march=armv7-a", "-mthumb", "-mfpu=neon", "-mfloat-abi=hard", "-mtune=cortex-a9", "-Wl,--gc-sections", "-L/opt/rtems-6-zynq-1/src/rtems/bsps/arm/shared/start", "-L/opt/rtems-6-zynq-1/src/rtems/bsps/arm/xilinx-zynq/start", "-o", "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/ada_tm20.exe"], []) = 0
>>
>> Now the trouble starts, there is no longer a "-march=armv7-a" option:
>>
>> [pid 110916] execve("/opt/rtems-6-zynq-1/bin/arm-rtems6-gcc", 
>> ["/opt/rtems-6-zynq-1/bin/arm-rtems6-gcc", "-c", "-mthumb", 
>> "-mfpu=neon", "-mfloat-abi=hard", "-mtune=cortex-a9", 
>> "--RTS=thumb/armv7-a+simd/hard", "-gnatA", "-gnatWb", "-gnatiw", 
>> "-gnatws", 
>> "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/b~tm20.adb"], []) = 0
>>
>> Here a "-march=armv4t" pops up.
>>
>> [pid 110917] 
>> execve("/opt/rtems-6-zynq-1/lib/gcc/arm-rtems6/13.2.1/gnat1", 
>> ["/opt/rtems-6-zynq-1/lib/gcc/arm-rtems6/13.2.1/gnat1", "-quiet", 
>> "-dumpbase", "b~tm20.adb", "-dumpbase-ext", ".adb", "-mthumb", 
>> "-mfpu=neon", "-mfloat-abi=hard", "-mtune=cortex-a9", 
>> "-fRTS=thumb/armv7-a+simd/hard", "-gnatA", "-gnatWb", "-gnatiw", 
>> "-gnatws", "-mcpu=arm7tdmi", "-mlibarch=armv4t", "-march=armv4t", 
>> "-ftls-model=local-exec", 
>> "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/b~tm20.adb", "-o", "/tmp/ccZhtzF7.s"], ["COLLECT_GCC=/opt/rtems-6-zynq-1/bin/arm-rtems6-gcc", "COLLECT_GCC_OPTIONS='-c' '-mthumb' '-mfpu=neon' '-mfloat-abi=hard' '-mtune=cortex-a9' '-fRTS=thumb/armv7-a+simd/hard' '-gnatA' '-gnatWb' '-gnatiw' '-gnatws' '-mcpu=arm7tdmi' '-mlibarch=armv4t' '-march=armv4t'"] <unfinished ...>
>>
>> Could someone give me a hint which component in GCC does this kind of 
>> option processing and mapping?
> 
> It looks like the bogus options are loaded from a ALI file. The ALI file 
> is produced by:
> 
> [pid 129509] 
> execve("/opt/rtems-6-zynq-1/lib/gcc/arm-rtems6/13.2.1/gnat1", 
> ["/opt/rtems-6-zynq-1/lib/gcc/arm-rtems6/13.2.1/gnat1", "-I", 
> "/opt/rtems-6-zynq-1/src/rtems/testsuites/ada/tmtests/tm21/", "-I", 
> "cpukit/include/adainclude", "-I", 
> "../../../../src/rtems/cpukit/include/adainclude", "-I", 
> "testsuites/ada/support", "-I", 
> "../../../../src/rtems/testsuites/ada/support", "-I", "-", "-quiet", 
> "-dumpdir", 
> "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/", "-dumpbase", "tm21.adb", "-dumpbase-ext", ".adb", "-gnatez", "-gnatea", "-mthumb", "-mfpu=neon", "-mfloat-abi=hard", "-mtune=cortex-a9", "-fRTS=thumb/armv7-a+simd/hard", "-gnatez", "-mlibarch=armv7-a+simd", "-march=armv7-a+simd", "-ftls-model=local-exec", "-gnatO", "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.o", "/opt/rtems-6-zynq-1/src/rtems/testsuites/ada/tmtests/tm21/tm21.adb", "-o", "/tmp/ccK4c8JY.s"], [..., "COLLECT_GCC=/opt/rtems-6-zynq-1//bin/arm-rtems6-gcc", "COLLECT_GCC_OPTIONS='-gnatea' '-c' '-I' '/opt/rtems-6-zynq-1/src/rtems/testsuites/ada/tmtests/tm21/' '-I' 'cpukit/include/adainclude' '-I' '../../../../src/rtems/cpukit/include/adainclude' '-I' 'testsuites/ada/support' '-I' '../../../../src/rtems/testsuites/ada/support'  '-mthumb' '-mfpu=neon' '-mfloat-abi=hard' '-mtune=cortex-a9' '-fRTS=thumb/armv7-a+simd/hard' '-I' '-' '-o' '/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.o' '-gnatez' '-mlibarch=armv7-a+simd' '-march=armv7-a+simd' '-dumpdir' '/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/'"] <unfinished ...>
> 
> This command has all the required options. It writes an ALI file:
> 
> [pid 129509] 
> unlink("/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.ali") = -1 ENOENT (No such file or directory)
> [pid 129509] openat(AT_FDCWD, 
> "/opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.ali", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 4
> 
> In this file not all required machine options are stored:
> 
> head 
> /opt/rtems-6-zynq-1/build/arm-xilinx_zynq_zc702-bsp-extra/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.ali
> V "GNAT Lib v13"
> M P W=b
> A -mthumb
> A -mfpu=neon
> A -mfloat-abi=hard
> A -mtune=cortex-a9
> A --RTS=thumb/armv7-a+simd/hard
> P ZX
> 
> RN
> 
> The "-march=armv7-a+simd" is missing.

Ok, I think the error is somewhere in the GCC main program. For this 
command line:

/opt/rtems-6-zynq-1/bin/arm-rtems6-gcc -gnatea -c 
-I/home/EB/sebastian_h/src/rtems/testsuites/ada/tmtests/tm21/ 
-Icpukit/include/adainclude 
-I/home/EB/sebastian_h/src/rtems/cpukit/include/adainclude 
-Itestsuites/ada/support 
-I/home/EB/sebastian_h/src/rtems/testsuites/ada/support -mthumb 
-march=armv7-a+simd -mfloat-abi=hard -mtune=cortex-a9 
--RTS=thumb/armv7-a+simd/hard -I- -o 
/tmp/sh/b-rtems/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.o 
/home/EB/sebastian_h/src/rtems/testsuites/ada/tmtests/tm21/tm21.adb -gnatez

The options are converted for gnat1 like this:

Breakpoint 3, pex_run_in_environment (obj=0x5ee660, flags=1, 
executable=0x5ec350 
"/opt/rtems-6-zynq-1/lib/gcc/arm-rtems6/13.2.1/gnat1", argv=0x5ee1e8,
     env=env@entry=0x0, orig_outname=0x0, errname=0x0, 
err=0x7fffffffd0ec) at 
/opt/rtems-6-zynq-1/src/gcc/libiberty/pex-common.c:156
156     {
(gdb) p *argv@40
$11 = {0x5ec350 "/opt/rtems-6-zynq-1/lib/gcc/arm-rtems6/13.2.1/gnat1", 
0x5e8540 "-I", 0x5e8550 
"/home/EB/sebastian_h/src/rtems/testsuites/ada/tmtests/tm21/",
   0x5e8590 "-I", 0x5e85a0 "cpukit/include/adainclude", 0x5e85c0 "-I", 
0x5e85d0 "/home/EB/sebastian_h/src/rtems/cpukit/include/adainclude", 
0x5e8610 "-I",
   0x5e8620 "testsuites/ada/support", 0x5e8640 "-I", 0x5e8650 
"/home/EB/sebastian_h/src/rtems/testsuites/ada/support", 0x5e8690 "-I", 
0x5e86a0 "-", 0x5e86b0 "-quiet",
   0x5e86c0 "-dumpdir", 0x5e86d0 
"/tmp/sh/b-rtems/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/", 
0x5e8720 "-dumpbase", 0x5e8730 "tm21.adb",
   0x5e8740 "-dumpbase-ext", 0x5e8750 ".adb", 0x5e8760 "-gnatez", 
0x5e8770 "-gnatea", 0x5e8780 "-mthumb", 0x5e8790 "-mfloat-abi=hard", 
0x5e87b0 "-mtune=cortex-a9",
   0x5e87d0 "-fRTS=thumb/armv7-a+simd/hard", 0x5e87f0 "-gnatez", 
0x5e8800 "-mlibarch=armv7-a+simd", 0x5e8820 "-march=armv7-a+simd", 
0x5e8840 "-ftls-model=local-exec",
   0x5e8860 "-gnatO", 0x5e8870 
"/tmp/sh/b-rtems/arm/xilinx_zynq_zc702/testsuites/ada/tmtests/tm21/tm21.o",
   0x5e88c0 
"/home/EB/sebastian_h/src/rtems/testsuites/ada/tmtests/tm21/tm21.adb", 
0x5e8910 "-o", 0x5e8920 "/tmp/ccOyyUfd.s", 0x0, 0x0, 0x0, 0x0, 0x0}

Here, the "-march=armv7-a+simd" was moved after the "-gnatez". So this 
option is dropped in switch-c.adb and doesn't get added to the ALI file.

-- 
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