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Forum: ARM programming with GCC/GNU tools normal to have undefined symbols?


normal to have undefined symbols?
von errolflynn (Guest)

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After compiling/linking a FreeRTOS program into an ELF file for 
ARM-Cortex M4 (ARMv7E-M) using arm-none-eabi tools, I see that some 
symbols are still undefined. Some are from libc/crt libraries.

The output of
1
arm-none-eabi-objdump -tT | grep --line-buffered "UND" | tee tmp.txt


is
1
00000000  w      *UND*  00000000 malloc

2
00000000  w      *UND*  00000000 __deregister_frame_info

3
00000000  w      *UND*  00000000 software_init_hook

4
00000000  w      *UND*  00000000 hardware_init_hook

5
00000000  w      *UND*  00000000 __libc_fini

6
00000000  w      *UND*  00000000 _Jv_RegisterClasses

7
00000000  w      *UND*  00000000 __register_frame_info

8
00000000  w      *UND*  00000000 free


This project uses CMake with the following compile and link flags:
1
set(GCC_COVERAGE_COMPILE_FLAGS "-march=armv7e-m -mthumb \

2
-mfloat-abi=softfp -mfpu=fpv4-sp-d16 -Og -fmessage-length=0 \

3
-fsigned-char -ffunction-sections -fdata-sections -ffreestanding \

4
-fno-move-loop-invariants -Wall -Wextra -g3")

5
6
set(GCC_COVERAGE_LINK_FLAGS

7
"-T \"${PROJECT_SOURCE_DIR}/ldscripts/mem.ld\" \

8
-T \"${PROJECT_SOURCE_DIR}/ldscripts/libs.ld\" \

9
-T \"${PROJECT_SOURCE_DIR}/ldscripts/sections.ld\" \

10
-Xlinker --gc-sections -Wl,-Map,\"elka.map\" \

11
--specs=nosys.specs")


As you can see, it uses
1
nosys

 specs, which uses Newlib I think.

  


  




  

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    Re: normal to have undefined symbols?
  


  

    

      von
      
        Erl S.
        (errolflynn)
        
      
      


      
    


    

      
    

    

    

  
  


  

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Edit (new acct):
For context, the program builds and runs with closed-source build tools, 
but I switched to open-source tools and now it builds but does not run.

  


  




  

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