How does watchpoint work in gdb and in what cases it is beneficial to used it ?

Question

I am working on some JIT compiler and I am using GDB to debut it, my code crashes at some point (segment fault), but it crashes at the jitted code (they are generated on the fly) so I do not get the stack frame information, But I got the following backtrace:

#0 0x**********d98f22 in ?? () // JITTED CODE
#1 0x000000000000001d in ?? () // JITTED CODE
#2 ...callattribuite function....

I am wondering if it is possible for GDB to disassemble the code at location 0x**********d98f22 and display it to me. I tried disas 0x**********d98f22 but GDB complained No function contains specified address.

Any clue?

Answer 1

During the unit testing, when tester suspects on the value of variable it may use "watch point" in gdb.
It prompts with old value and new value whenever value of a variable gets changed. There is a limitation of watch point is that it works on a variable till the scope of variable. I meant to say if a variable is declared as global, watch dog will work throughout the program while for a variable with local scope watch point leaves tracking variable as soon as it goes out of scope.