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Align source and assembly

Poonam

I have a source file, converted it to assembly and added 2 instructions and generated the final elf. When I load this final elf, symbols doesnt match the source due to assembly instructions addition.

Is there a way to align them ? am using ARM cortex-M4 and cortex-M0. I have tried to edit #line in assembly file to make sure lines match with source code but that doesn't give a good alignment. Any ideas?

  • Hello,

    please give us the concrete source code and dis-assembly code of the elf?

    Best regards,

    Yasuhiko Koumoto.

  • in reply to Yasuhiko Koumoto

    Source file: test3.c

    Modified assembly is test3_qcm.S

    Output : final.elf

    commands I am using to generate the output

    REM C:\Apps\ARMCT5.05\106\bin\armcc.exe --thumb --cpu Cortex-M4 -DT_ARM -D__ARMEL__ -D__RVCT__ --apcs /noswst/interwork --littleend --force_new_nothrow -g --dwarf2 -Otime -O1 -c -S -o test3.S test3.c

    REM modify the file

    C:\Apps\ARMCT5.05\106\bin\armasm.exe --cpu Cortex-M4 --apcs /noswst/interwork -g --dwarf2  test3_qcm.S -o test3.o

    C:\Apps\ARMCT5.05\106\bin\armlink.exe --elf --map --info sizes,totals --list test3.map --symbols --symdefs test3.sym test3.o -o final.elf

    test3.c

    ---------

    1. #include<stdio.h>
    4. void foo2()
    5. {
    6.     printf("In foo2");
    7.    
    9. }
    11. void foo1()
    12. {
    13.     printf("In foo1");
    14.    
    16. }
    17. int cubed(int i)
    18. {
    19. return i*i*i;
    20. }
    22. int main()
    23. {
    24.     int n = 3;
    25.     printf("%d cubed = %d\n",n,cubed(n));
    26.     printf("Hello world");
    27.     foo1();
    28.     foo2();
    30. }

    Modified assembly test3_qcm.S

    -----------------------------

    ; generated by Component: ARM Compiler 5.05 update 1 (build 106) Tool: armcc [4d0efa]

    ; commandline armcc [--thumb --dwarf2 --debug -c -S -otest3.S --cpu=Cortex-M4 --apcs=/noswst/interwork -O1 -Otime --sitelicense -DT_ARM -D__ARMEL__ -D__RVCT__ --force_new_nothrow test3.c]

            THUMB

            REQUIRE8

            PRESERVE8

            AREA ||.text||, CODE, READONLY, ALIGN=2

            REQUIRE _printf_percent

            REQUIRE _printf_d

            REQUIRE _printf_int_dec

    foo2 PROC

           PUSH {R0}

           POP {R0}

    #line 5 "test3.c"

            ADR      r0,|L0.60|

            B.W      __2printf

    #line 9 "test3.c"

            ENDP

    foo1 PROC

           PUSH {R0}

           POP {R0}

    #line 12 "test3.c"

            ADR      r0,|L0.68|

            B.W      __2printf

    #line 16 "test3.c"

            ENDP

    cubed PROC

           PUSH {R0}

           POP {R0}

    #line 17 "test3.c"

            MUL      r1,r0,r0

            MULS     r0,r1,r0

            BX       lr

    #line 20 "test3.c"

            ENDP

    main PROC

           PUSH {R0}

           POP {R0}

    #line 24 "test3.c"

            PUSH     {r4,lr}

            MOVS     r3,#3

            MOV      r0,r3

            BL       cubed

            MOV      r2,r0

            MOV      r1,r3

            ADR      r0,|L0.76|

            BL       __2printf

            ADR      r0,|L0.92|

            BL       __2printf

            BL       foo1

            BL       foo2

            MOVS     r0,#0

            POP      {r4,pc}

    #line 29 "test3.c"

            ENDP

            DCW      0x0000

    |L0.60|

            DCB      "In foo2",0

    |L0.68|

            DCB      "In foo1",0

    |L0.76|

            DCB      "%d cubed = %d\n",0

            DCB      0

    |L0.92|

            DCB      "Hello world",0

            AREA ||.arm_vfe_header||, DATA, READONLY, NOALLOC, ALIGN=2

            DCD      0x00000000

    __ARM_use_no_argv EQU 0

            EXPORT __ARM_use_no_argv

            EXPORT foo2 [CODE]

            EXPORT foo1 [CODE]

            EXPORT cubed [CODE]

            EXPORT main [CODE]

            IMPORT ||Lib$$Request$$armlib|| [CODE,WEAK]

            IMPORT __2printf [CODE]

            IMPORT _printf_percent [CODE]

            IMPORT _printf_d [CODE]

            IMPORT _printf_int_dec [CODE]

            ATTR FILESCOPE

            ATTR SETVALUE Tag_ABI_PCS_wchar_t,2

            ATTR SETVALUE Tag_ABI_enum_size,1

            ATTR SETVALUE Tag_ABI_optimization_goals,1

            ATTR SETSTRING Tag_conformance,"2.06"

            ATTR SETVALUE AV,18,1

            ASSERT {ENDIAN} = "little"

            ASSERT {INTER} = {TRUE}

            ASSERT {ROPI} = {FALSE}

            ASSERT {RWPI} = {FALSE}

            ASSERT {IEEE_FULL} = {FALSE}

            ASSERT {IEEE_PART} = {FALSE}

            ASSERT {IEEE_JAVA} = {FALSE}

            END

    Orginal test3.S generated with armcc -S

    -----------------------------------------------

    ; generated by Component: ARM Compiler 5.05 update 1 (build 106) Tool: armcc [4d0efa]

    ; commandline armcc [--thumb --dwarf2 --debug -c -S -otest3.S --cpu=Cortex-M4 --apcs=/noswst/interwork -O1 -Otime --sitelicense -DT_ARM -D__ARMEL__ -D__RVCT__ --force_new_nothrow test3.c]

            THUMB

            REQUIRE8

            PRESERVE8

            AREA ||.text||, CODE, READONLY, ALIGN=2

            REQUIRE _printf_percent

            REQUIRE _printf_d

            REQUIRE _printf_int_dec

    foo2 PROC

            ADR      r0,|L0.60|

            B.W      __2printf

            ENDP

    foo1 PROC

            ADR      r0,|L0.68|

            B.W      __2printf

            ENDP

    cubed PROC

            MUL      r1,r0,r0

            MULS     r0,r1,r0

            BX       lr

            ENDP

    main PROC

            PUSH     {r4,lr}

            MOVS     r3,#3

            MOV      r0,r3

            BL       cubed

            MOV      r2,r0

            MOV      r1,r3

            ADR      r0,|L0.76|

            BL       __2printf

            ADR      r0,|L0.92|

            BL       __2printf

            BL       foo1

            BL       foo2

            MOVS     r0,#0

            POP      {r4,pc}

            ENDP

            DCW      0x0000

    |L0.60|

            DCB      "In foo2",0

    |L0.68|

            DCB      "In foo1",0

    |L0.76|

            DCB      "%d cubed = %d\n",0

            DCB      0

    |L0.92|

            DCB      "Hello world",0

            AREA ||.arm_vfe_header||, DATA, READONLY, NOALLOC, ALIGN=2

            DCD      0x00000000

    __ARM_use_no_argv EQU 0

            EXPORT __ARM_use_no_argv

            EXPORT foo2 [CODE]

            EXPORT foo1 [CODE]

            EXPORT cubed [CODE]

            EXPORT main [CODE]

            IMPORT ||Lib$$Request$$armlib|| [CODE,WEAK]

            IMPORT __2printf [CODE]

            IMPORT _printf_percent [CODE]

            IMPORT _printf_d [CODE]

            IMPORT _printf_int_dec [CODE]

            ATTR FILESCOPE

            ATTR SETVALUE Tag_ABI_PCS_wchar_t,2

            ATTR SETVALUE Tag_ABI_enum_size,1

            ATTR SETVALUE Tag_ABI_optimization_goals,1

            ATTR SETSTRING Tag_conformance,"2.06"

            ATTR SETVALUE AV,18,1

            ASSERT {ENDIAN} = "little"

            ASSERT {INTER} = {TRUE}

            ASSERT {ROPI} = {FALSE}

            ASSERT {RWPI} = {FALSE}

            ASSERT {IEEE_FULL} = {FALSE}

            ASSERT {IEEE_PART} = {FALSE}

            ASSERT {IEEE_JAVA} = {FALSE}

            END

    Alignment seen on T32:

    -----------------------------------

  • in reply to Poonam

    Alignment seen on T32, Tried to highlight the source code

    -----------------------------------

    ______addr/line|code_____|label____|mnemonic________________|comment______________________________________________________|

                   |...

                   |

                   |        REQUIRE _printf_percent

                   |        REQUIRE _printf_d

                   |        REQUIRE _printf_int_dec

                   |

                   |foo2 PROC

                   |

                   |                           ; PATCH TOOL - START

                 16|       PUSH {R0}

        ST:00008098|B401      foo2:     push    {r0}

                 17|       POP {R0}

        ST:0000809A|BC01                pop     {r0}

                   |#include<stdio.h>

                   |

                   |

                   |void foo2()         ------------------ this is what I inserted

                  5|{                      

    ____ST:0000809C|A011________________add_____r0,pc,#0x44

                  6|        printf("In foo2");

        ST:0000809E|F000                bl_h    0x809E

        ST:000080A0|B837                undef   0xB837

                   |

                   |

                  |}

                   |

                   |void foo1() ------------------  this is what came by default

                 12|{

        ST:000080A2|B401      foo1:     push    {r0}

                 13|        printf("In foo1");

        ST:000080A4|BC01                pop     {r0}

                   |

                   |

                  |}

                   |

                   |void foo1()------------------ this is what I inserted

                 12|{                                                    

        ST:000080A6|A011                add     r0,pc,#0x44

                 13|        printf("In foo1");

        ST:000080A8|F000                bl_h    0x80A8

        ST:000080AA|B832                undef   0xB832

                   |

                   |

                   |}

  • in reply to Poonam

    Hello,

    I think you should put extra "#line" before the new instruction such as PUSH or POP.

    The "#line" will reset the line number to the parameter of it.

    Best regards,

    Yasuhiko Koumoto.

  • in reply to Yasuhiko Koumoto

    Tried adding extra #line before inserted instructions but doesn't help.

  • in reply to Yasuhiko Koumoto

    It appears that generated assembly-object file doesn't have all the debug information as compared to object created from source. Any idea how they can be generated?

    Here are the few things tried already

    Compiler  options: --debug --dwarf3 --debug_macros

    Assembler options: --debug

    Liner options: --bestdebug

    --interleave doesn’t allow to reassemble the files.

  • in reply to Poonam

    Hello,

    can I ask your expectation?

    As you say, the elf file includes many debug information.

    What do you especially want?

    Best regards,

    Yasuhiko Koumoto.