Can I give objdump an address and have it disassemble the containing function?
objdump --start-address=
perhaps ?
GDB disassemble
gdb -batch -ex "file $EXECUTABLE" -ex "disassemble/rs $ADDRESS"
For example:
a.c
#include <assert.h>
int myfunc(int i) {
i = i + 2;
i = i * 2;
return i;
}
int main(void) {
assert(myfunc(1) == 6);
assert(myfunc(2) == 8);
return 0;
}
Compile and disassemble myfunc
to find an address:
gcc -std=c99 -O0 -g a.c
gdb -batch -ex 'file a.out' -ex "disassemble/rs myfunc"
Output:
Dump of assembler code for function myfunc:
a.c:
3 int myfunc(int i) {
0x000000000000064a <+0>: 55 push %rbp
0x000000000000064b <+1>: 48 89 e5 mov %rsp,%rbp
0x000000000000064e <+4>: 89 7d fc mov %edi,-0x4(%rbp)
4 i = i + 2;
0x0000000000000651 <+7>: 83 45 fc 02 addl $0x2,-0x4(%rbp)
5 i = i * 2;
0x0000000000000655 <+11>: d1 65 fc shll -0x4(%rbp)
6 return i;
0x0000000000000658 <+14>: 8b 45 fc mov -0x4(%rbp),%eax
7 }
0x000000000000065b <+17>: 5d pop %rbp
0x000000000000065c <+18>: c3 retq
End of assembler dump.
OK, so 0x0000000000000655 is in myfunc
, let's confirm it works:
gdb -batch -ex 'file a.out' -ex 'disassemble/rs 0x0000000000000655'
Output: same as previous disassembly.
See also: How to disassemble one single function using objdump?
Tested on Ubuntu 18.04, GDB 8.1.
Something like this perhaps?
$ objdump -S --start-address=0x42 foo.o | awk '{print $0} $3~/retq?/{exit}'
It prints the dis-assembly listing starting from 0x42
till it finds a ret(q)
, assuming the boundary is marked by ret(q)