function call seems not working properly in disassembled code [duplicate] - c++

Question

This question already has an answer here:
What are these seemingly-useless callq instructions in my x86 object files for?
(1 answer)
Closed 1 year ago.
I wrote a simple program and then compiled and assembled it.
tfc.cpp
int i = 0;
void f(int a)
{
i += a;
};
int main()
{
f(9);
return 0;
};
I got the tfc.o by running
$ g++ -c -O1 tfc.cpp
Then I use gobjdump (objdump) to disassemble the binary file.
$ gobjdump -d tfc.o
Then I got
0000000000000000 <__Z1fi>:
0: 55 push %rbp
1: 48 89 e5 mov %rsp,%rbp
4: 01 3d 00 00 00 00 add %edi,0x0(%rip) # a <__Z1fi+0xa>
a: 5d pop %rbp
b: c3 retq
c: 0f 1f 40 00 nopl 0x0(%rax)
0000000000000010 <_main>:
10: 55 push %rbp
11: 48 89 e5 mov %rsp,%rbp
14: bf 09 00 00 00 mov $0x9,%edi
19: e8 00 00 00 00 callq 1e <_main+0xe>
1e: 31 c0 xor %eax,%eax
20: 5d pop %rbp
21: c3 retq
The weird thing happened, the callq instruction is followed by 1e <_main+0xe>. Shouldn't it be the address of <__Z1fi>? If not, how does the main function call the f function?
EDIT
FYI:
$ g++ -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.1.0
Thread model: posix

Answer 1

It calls address 0, which is the address of the f function.
e8 is the call instruction in x86 according to this:
http://www.cs.cmu.edu/~fp/courses/15213-s07/misc/asm64-handout.pdf
call uses the displacement relative to the next instruction, at memory location 1e. That becomes memory location 0. So it's callq 1e when in reality it's calling address 0.