Question

If you have a particular line of C code in mind to examine in the machine output, how would you locate it in objdump output. Here is an example

if (cond)    foo;    bar(); 

and I want to see if bar was inlined as I’d like. Or would you use some alternative tool instead of objdump?

Answer 1

You can start objdump using the -S option (like 'objdump -Sd a.out'). It will display the sourcecode intermixxed with the assembler code, if the source-files the code was compiled from are available.

Alternatively, you can use the following way:

int main(void) {     int a = 0;     asm('#');     return a; } 

becomes

       .file   'a.c'         .text .globl main         .type   main, @function main:         leal    4(%esp), %ecx         andl    $-16, %esp         pushl   -4(%ecx)         pushl   %ebp         movl    %esp, %ebp         pushl   %ecx         subl    $16, %esp         movl    $0, -8(%ebp) #APP # 3 'a.c' 1         # # 0 '' 2 #NO_APP         movl    -8(%ebp), %eax         addl    $16, %esp         popl    %ecx         popl    %ebp         leal    -4(%ecx), %esp         ret         .size   main, .-main         .ident  'GCC: (GNU) 4.3.2'         .section        .note.GNU-stack,'',@progbits