# An example of a function which has been split into two parts. Roughly # corresponds to this C code. # int baz() { return 47; } # int bar() { return foo(0); } # int foo(int flag) { return flag ? bar() : baz(); } # int main() { return foo(1); } # The function bar has been placed "in the middle" of foo. The functions are not # using the frame pointer register and the are deliberately adjusting the stack # pointer to test that we're using the correct unwind row. .text .type baz,@function baz: .cfi_startproc movl $47, %eax retq .cfi_endproc .Lbaz_end: .size baz, .Lbaz_end-baz foo.__part.3: .cfi_startproc .cfi_def_cfa_offset 32 .cfi_offset %rbx, -16 addq $24, %rsp .cfi_def_cfa %rsp, 8 retq .Lfoo.__part.3_end: .size foo.__part.3, .Lfoo.__part.3_end-foo.__part.3 .cfi_endproc # NB: Deliberately inserting padding to separate the two parts of the function # as we're currently only parsing a single FDE entry from a (coalesced) address # range. nop foo.__part.1: .cfi_startproc .cfi_def_cfa_offset 32 .cfi_offset %rbx, -16 subq $16, %rsp .cfi_def_cfa_offset 48 callq bar addq $16, %rsp .cfi_def_cfa_offset 32 jmp foo.__part.3 .Lfoo.__part.1_end: .size foo.__part.1, .Lfoo.__part.1_end-foo.__part.1 .cfi_endproc bar: .cfi_startproc subq $88, %rsp .cfi_def_cfa_offset 96 xorl %edi, %edi callq foo addq $88, %rsp .cfi_def_cfa %rsp, 8 retq .cfi_endproc .Lbar_end: .size bar, .Lbar_end-bar .type foo,@function foo: .cfi_startproc pushq %rbx .cfi_def_cfa_offset 16 .cfi_offset %rbx, -16 movl %edi, %ebx cmpl $0, %ebx je foo.__part.2 subq $16, %rsp .cfi_def_cfa_offset 32 jmp foo.__part.1 .cfi_endproc .Lfoo_end: .size foo, .Lfoo_end-foo # NB: Deliberately inserting padding to separate the two parts of the function # as we're currently only parsing a single FDE entry from a (coalesced) address # range. nop foo.__part.2: .cfi_startproc .cfi_def_cfa_offset 16 .cfi_offset %rbx, -16 subq $16, %rsp .cfi_def_cfa_offset 32 callq baz jmp foo.__part.3 .Lfoo.__part.2_end: .size foo.__part.2, .Lfoo.__part.2_end-foo.__part.2 .cfi_endproc .globl main .type main,@function main: .cfi_startproc movl $1, %edi callq foo retq .cfi_endproc .Lmain_end: .size main, .Lmain_end-main .section .debug_abbrev,"",@progbits .byte 1 # Abbreviation Code .byte 17 # DW_TAG_compile_unit .byte 1 # DW_CHILDREN_yes .byte 37 # DW_AT_producer .byte 8 # DW_FORM_string .byte 19 # DW_AT_language .byte 5 # DW_FORM_data2 .byte 17 # DW_AT_low_pc .byte 1 # DW_FORM_addr .byte 85 # DW_AT_ranges .byte 35 # DW_FORM_rnglistx .byte 116 # DW_AT_rnglists_base .byte 23 # DW_FORM_sec_offset .byte 0 # EOM(1) .byte 0 # EOM(2) .byte 2 # Abbreviation Code .byte 46 # DW_TAG_subprogram .byte 0 # DW_CHILDREN_no .byte 17 # DW_AT_low_pc .byte 1 # DW_FORM_addr .byte 18 # DW_AT_high_pc .byte 1 # DW_FORM_addr .byte 3 # DW_AT_name .byte 8 # DW_FORM_string .byte 0 # EOM(1) .byte 0 # EOM(2) .byte 3 # Abbreviation Code .byte 46 # DW_TAG_subprogram .byte 1 # DW_CHILDREN_yes .byte 85 # DW_AT_ranges .byte 35 # DW_FORM_rnglistx .byte 64 # DW_AT_frame_base .byte 24 # DW_FORM_exprloc .byte 3 # DW_AT_name .byte 8 # DW_FORM_string .byte 0 # EOM(1) .byte 0 # EOM(2) .byte 4 # Abbreviation Code .byte 5 # DW_TAG_formal_parameter .byte 0 # DW_CHILDREN_no .byte 2 # DW_AT_location .byte 24 # DW_FORM_exprloc .byte 3 # DW_AT_name .byte 8 # DW_FORM_string .byte 73 # DW_AT_type .byte 19 # DW_FORM_ref4 .byte 0 # EOM(1) .byte 0 # EOM(2) .byte 5 # Abbreviation Code .byte 36 # DW_TAG_base_type .byte 0 # DW_CHILDREN_no .byte 3 # DW_AT_name .byte 8 # DW_FORM_string .byte 62 # DW_AT_encoding .byte 11 # DW_FORM_data1 .byte 11 # DW_AT_byte_size .byte 11 # DW_FORM_data1 .byte 0 # EOM(1) .byte 0 # EOM(2) .byte 0 # EOM(3) .section .debug_info,"",@progbits .Lcu_begin0: .long .Ldebug_info_end0-.Ldebug_info_start0 # Length of Unit .Ldebug_info_start0: .short 5 # DWARF version number .byte 1 # DWARF Unit Type .byte 8 # Address Size (in bytes) .long .debug_abbrev # Offset Into Abbrev. Section .byte 1 # Abbrev [1] DW_TAG_compile_unit .asciz "Hand-written DWARF" # DW_AT_producer .short 29 # DW_AT_language .quad 0 # DW_AT_low_pc .byte 1 # DW_AT_ranges .long .Lrnglists_table_base0 # DW_AT_rnglists_base .byte 2 # Abbrev [2] DW_TAG_subprogram .quad baz # DW_AT_low_pc .quad .Lbaz_end # DW_AT_high_pc .asciz "baz" # DW_AT_name .byte 2 # Abbrev [2] DW_TAG_subprogram .quad bar # DW_AT_low_pc .quad .Lbar_end # DW_AT_high_pc .asciz "bar" # DW_AT_name .byte 3 # Abbrev [3] DW_TAG_subprogram .byte 0 # DW_AT_ranges .byte 1 # DW_AT_frame_base .byte 86 .asciz "foo" # DW_AT_name .byte 4 # Abbrev [4] DW_TAG_formal_parameter .byte 1 # DW_AT_location .byte 0x53 # DW_OP_reg3 .asciz "flag" # DW_AT_name .long .Lint-.Lcu_begin0 # DW_AT_type .byte 0 # End Of Children Mark .byte 2 # Abbrev [2] DW_TAG_subprogram .quad main # DW_AT_low_pc .quad .Lmain_end # DW_AT_high_pc .asciz "main" # DW_AT_name .Lint: .byte 5 # Abbrev [5] DW_TAG_base_type .asciz "int" # DW_AT_name .byte 5 # DW_AT_encoding .byte 4 # DW_AT_byte_size .byte 0 # End Of Children Mark .Ldebug_info_end0: .section .debug_rnglists,"",@progbits .long .Ldebug_list_header_end0-.Ldebug_list_header_start0 # Length .Ldebug_list_header_start0: .short 5 # Version .byte 8 # Address size .byte 0 # Segment selector size .long 2 # Offset entry count .Lrnglists_table_base0: .long .Ldebug_ranges0-.Lrnglists_table_base0 .long .Ldebug_ranges1-.Lrnglists_table_base0 .Ldebug_ranges0: .byte 6 # DW_RLE_start_end .quad foo .quad .Lfoo_end .byte 6 # DW_RLE_start_end .quad foo.__part.1 .quad .Lfoo.__part.1_end .byte 6 # DW_RLE_start_end .quad foo.__part.2 .quad .Lfoo.__part.2_end .byte 6 # DW_RLE_start_end .quad foo.__part.3 .quad .Lfoo.__part.3_end .byte 0 # DW_RLE_end_of_list .Ldebug_ranges1: .byte 6 # DW_RLE_start_end .quad baz .quad .Lbaz_end .byte 6 # DW_RLE_start_end .quad bar .quad .Lbar_end .byte 6 # DW_RLE_start_end .quad foo.__part.1 .quad .Lfoo.__part.1_end .byte 6 # DW_RLE_start_end .quad foo.__part.2 .quad .Lfoo.__part.2_end .byte 6 # DW_RLE_start_end .quad foo.__part.3 .quad .Lfoo.__part.3_end .byte 6 # DW_RLE_start_end .quad foo .quad .Lfoo_end .byte 6 # DW_RLE_start_end .quad main .quad .Lmain_end .byte 0 # DW_RLE_end_of_list .Ldebug_list_header_end0: .section ".note.GNU-stack","",@progbits