Question

There seem to be a .CFI directive after every line and also there are wide varieties of these ex.,.cfi_startproc , .cfi_endproc etc.. more here.

    .file   "temp.c"
    .text
.globl main
    .type   main, @function
main:
.LFB0:
    .cfi_startproc
    pushq   %rbp
    .cfi_def_cfa_offset 16
    movq    %rsp, %rbp
    .cfi_offset 6, -16
    .cfi_def_cfa_register 6
    movl    $0, %eax
    leave
    ret
    .cfi_endproc
.LFE0:
    .size   main, .-main
.globl func
    .type   func, @function
func:
.LFB1:
    .cfi_startproc
    pushq   %rbp
    .cfi_def_cfa_offset 16
    movq    %rsp, %rbp
    .cfi_offset 6, -16
    .cfi_def_cfa_register 6
    movl    %edi, -4(%rbp)
    movl    %esi, %eax
    movb    %al, -8(%rbp)
    leave
    ret
    .cfi_endproc
.LFE1:
    .size   func, .-func
    .ident  "GCC: (Ubuntu 4.4.1-4ubuntu9) 4.4.1"
    .section    .note.GNU-stack,"",@progbits

I didn’t get the purpose of these.

Answer 1

I’ve got a feeling it stands for Call Frame Information and is a GNU AS extension to manage call frames. From DeveloperWorks:

On some architectures, exception
handling must be managed with Call
Frame Information directives. These
directives are used in the assembly to
direct exception handling. These
directives are available on Linux on
POWER, if, for any reason (portability
of the code base, for example), the
GCC generated exception handling
information is not sufficient.

It looks like these are generated on some platforms depending on need for exception handling.

If you are looking to disable these, please see David’s answer.