gdb - list source of current function without typing its name

gdbtui can be useful to view the source during debugging.

When you are stopped in a function type bt for backtrace. Backtrace will list the current stack. The element at the top, #0, is usually the function you are interested in and the source file and line number is listed also.

For example:

(gdb) bt
#0  myClass::EntityTypeStruct::readAttributes (this=0x7fffd00066e0, buf=0x7fffd0006020 "", len=48)
    at /team/project/src/EntityTypeStruct.cc:55
#1  0x000000000044ca86 in workerThread (ts=0x7fffea71dcc0)
    at /team/project/src/threads/workerThread.cc:219
#2  0x00007ffff775e9d1 in start_thread () from /lib64/libpthread.so.0
#3  0x00007ffff6c07b5d in clone () from /lib64/libc.so.6

See http://www.chemie.fu-berlin.de/chemnet/use/info/gdb/gdb_7.html#SEC42 for more info.

Also, when you set a breakpoint you can specify commands that will run everytime you hit that breakpoint. See http://www.chemie.fu-berlin.de/chemnet/use/info/gdb/gdb_6.html#SEC35

So, if you know how many lines are in your function you could set a command to list all source lines of the function:

(gdb) break myClass::EntityTypeStruct::readAttributes
Breakpoint 1 at 0x61ec3b: file /team/project/src/EntityTypeStruct.cc, line 38.
(gdb) commands 1
list 38,104
end

(gdb) help list
List specified function or line.
With no argument, lists ten more lines after or around previous listing.
"list -" lists the ten lines before a previous ten-line listing.
One argument specifies a line, and ten lines are listed around that line.
Two arguments with comma between specify starting and ending lines to list.
Lines can be specified in these ways:
  LINENUM, to list around that line in current file,
  FILE:LINENUM, to list around that line in that file,
  FUNCTION, to list around beginning of that function,
  FILE:FUNCTION, to distinguish among like-named static functions.
  *ADDRESS, to list around the line containing that address.
With two args if one is empty it stands for ten lines away from the other arg.

The *ADDRESS is what is interesting.

On x86/x64 current pointer is in rip register so:

(gdb) list *$pc
0x7ffff7b018a0 is at ../sysdeps/unix/syscall-template.S:82.
77  in ../sysdeps/unix/syscall-template.S

The example is from cat command as I don't have anything with debug info at hand.

The 'frame' command shows the function name and the current line location and sets the current line for list to the current executable line.

set listsize 17
frame
list

lists the 8 lines surrounding the current line.