How to load multiple symbol files in gdb

Question

How to load multiple symbol files in gdb. I have a executable foo.out and loading a module bar.so. I have created two symbol files foo.symbol and bar.symbol. Ho

Answer 1

Additional symbols can be loaded to the gdb debug session with:

add-symbol-file filename address

Parameter address is the address for .text section. This address can be retrieved with:

readelf -WS path/to/file.elf | grep .text | awk '{ print "0x"$5 }'

This can be automated in gdb by adding following entry to ~/.gdbinit:

define add-symbol-file-auto
  # Parse .text address to temp file
  shell echo set \$text_address=$(readelf -WS $arg0 | grep .text | awk '{ print "0x"$5 }') >/tmp/temp_gdb_text_address.txt

  # Source .text address
  source /tmp/temp_gdb_text_address.txt

  #  Clean tempfile
  shell rm -f /tmp/temp_gdb_text_address.txt

  # Load symbol table
  add-symbol-file $arg0 $text_address
end

After above function definition add-symbol-file-auto can be used load additional symbols:

(gdb) add-symbol-file-auto path/to/bootloader.elf
add symbol table from file "path/to/bootloader.elf" at
    .text_addr = 0x8010400
(gdb) add-symbol-file-auto path/to/application.elf
add symbol table from file "path/to/application.elf" at
    .text_addr = 0x8000000
(gdb) break main
Breakpoint 1 at 0x8006cb0: main. (2 locations)
(gdb) info break
Num     Type           Disp Enb Address    What
1       breakpoint     keep y    
1.1                         y     0x08006cb0 in main() at ./source/main.cpp:114
1.2                         y     0x080106a6 in main() at ./main.cpp:10
(gdb)