stacktrace: Print offset of binary instead of address

It'd be better to print related address based on its load address.
It needs to calculate the load base and print offset instead of address.

<Without this patch>
 0 [0x7f4993dd460f] malloc +0x1f
 1 [0x55d3bc1e81bf] main +0x5
 2 [0x7f4993bc7d90] /lib/x86_64-linux-gnu/libc.so.6 (+0x7f4993bc7d90)
 3 [0x7f4993bc7e40] __libc_start_main +0x20
 4 [0x55d3bc1e80e5] _start +0x9

<With this commit>
 0 [0x7f67b66bf60f] malloc +0x1f
 1 [0x5645cb2cc1bf] main +0x5
 2 [0x7f67b64b2d90] /lib/x86_64-linux-gnu/libc.so.6 (+0x29d90)
 3 [0x7f67b64b2e40] __libc_start_main +0x20
 4 [0x5645cb2cc0e5] _start +0x9

Signed-off-by: Bojun Seo <[email protected]>

stacktrace.cc

@@ -127,9 +127,8 @@ static void print_backtrace_symbol(int count, void *addr)
 		free(symbol);
 	}
 	else {
-		// TODO: It'd be better to print related address based on its
-		//       load address.  It needs to calculate the load base.
-		pr_out("%s (+%p)\n", dlip.dli_fname, addr);
+		offset = (int)((char*)addr - (char*)(dlip.dli_fbase));
+		pr_out("%s (+%#x)\n", dlip.dli_fname, offset);
 	}
 }