Bing Xia's Blog: July 2010

GDB has a better capability to display the content of STL templates than WinDBG.

The trick is the following script by Dr. Eng. Dan C. Marinescu

####### Begin of Script #########
#   STL GDB evaluators/views/utilities - 1.03
#
#   The new GDB commands:
#         are entirely non instrumental
#         do not depend on any "inline"(s) - e.g. size(), [], etc
#       are extremely tolerant to debugger settings
#
#   This file should be "included" in .gdbinit as following:
#   source stl-views.gdb or just paste it into your .gdbinit file
#
#   The following STL containers are currently supported:
#
#       std::vector -- via pvector command
#       std::list -- via plist or plist_member command
#       std::map -- via pmap or pmap_member command
#       std::multimap -- via pmap or pmap_member command
#       std::set -- via pset command
#       std::multiset -- via pset command
#       std::deque -- via pdequeue command
#       std::stack -- via pstack command
#       std::queue -- via pqueue command
#       std::priority_queue -- via ppqueue command
#       std::bitset -- via pbitset command
#       std::string -- via pstring command
#       std::widestring -- via pwstring command
#
#   The end of this file contains (optional) C++ beautifiers
#   Make sure your debugger supports $argc
#
#   Simple GDB Macros writen by Dan Marinescu (H-PhD) - License GPL
#   Inspired by intial work of Tom Malnar,
#     Tony Novac (PhD) / Cornell / Stanford,
#     Gilad Mishne (PhD) and Many Many Others.
#   Contact: dan_c_marinescu@yahoo.com (Subject: STL)
#
#   Modified to work with g++ 4.3 by Anders Elton
#   Also added _member functions, that instead of printing the entire class in map, prints a member.

#
# std::vector<>
#

define pvector
   if $argc == 0
       help pvector
   else
       set $size = $arg0._M_impl._M_finish - $arg0._M_impl._M_start
       set $capacity = $arg0._M_impl._M_end_of_storage - $arg0._M_impl._M_start
       set $size_max = $size - 1
   end
   if $argc == 1
       set $i = 0
       while $i < $size
           printf "elem[%u]: ", $i
           p *($arg0._M_impl._M_start + $i)
           set $i++
       end
   end
   if $argc == 2
       set $idx = $arg1
       if $idx < 0 || $idx > $size_max
           printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
       else
           printf "elem[%u]: ", $idx
           p *($arg0._M_impl._M_start + $idx)
       end
   end
   if $argc == 3
      set $start_idx = $arg1
      set $stop_idx = $arg2
      if $start_idx > $stop_idx
        set $tmp_idx = $start_idx
        set $start_idx = $stop_idx
        set $stop_idx = $tmp_idx
      end
      if $start_idx < 0 || $stop_idx < 0 || $start_idx > $size_max || $stop_idx > $size_max
        printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
      else
        set $i = $start_idx
       while $i <= $stop_idx
           printf "elem[%u]: ", $i
           p *($arg0._M_impl._M_start + $i)
           set $i++
       end
      end
   end
   if $argc > 0
       printf "Vector size = %u\n", $size
       printf "Vector capacity = %u\n", $capacity
       printf "Element "
       whatis $arg0._M_impl._M_start
   end
end

document pvector
   Prints std::vector information.
   Syntax: pvector
   Note: idx, idx1 and idx2 must be in acceptable range [0...size()-1].
   Examples:
   pvector v - Prints vector content, size, capacity and T typedef
   pvector v 0 - Prints element[idx] from vector
   pvector v 1 2 - Prints elements in range [idx1..idx2] from vector
end

#
# std::list<>
#

define plist
   if $argc == 0
       help plist
   else
       set $head = &$arg0._M_impl._M_node
       set $current = $arg0._M_impl._M_node._M_next
       set $size = 0
       while $current != $head
           if $argc == 2
               printf "elem[%u]: ", $size
               p *($arg1*)($current + 1)
           end
           if $argc == 3
               if $size == $arg2
                   printf "elem[%u]: ", $size
                   p *($arg1*)($current + 1)
               end
           end
           set $current = $current._M_next
           set $size++
       end
       printf "List size = %u \n", $size
       if $argc == 1
           printf "List "
           whatis $arg0
           printf "Use plist to see the elements in the list.\n"
       end
   end
end

document plist
   Prints std::list information.
   Syntax: plist : Prints list size, if T defined all elements or just element at idx
   Examples:
   plist l - prints list size and definition
   plist l int - prints all elements and list size
   plist l int 2 - prints the third element in the list (if exists) and list size
end

define plist_member
   if $argc == 0
       help plist_member
   else
       set $head = &$arg0._M_impl._M_node
       set $current = $arg0._M_impl._M_node._M_next
       set $size = 0
       while $current != $head
           if $argc == 3
               printf "elem[%u]: ", $size
               p (*($arg1*)($current + 1)).$arg2
           end
           if $argc == 4
               if $size == $arg3
                   printf "elem[%u]: ", $size
                   p (*($arg1*)($current + 1)).$arg2
               end
           end
           set $current = $current._M_next
           set $size++
       end
       printf "List size = %u \n", $size
       if $argc == 1
           printf "List "
           whatis $arg0
           printf "Use plist_member to see the elements in the list.\n"
       end
   end
end

document plist_member
   Prints std::list information.
   Syntax: plist : Prints list size, if T defined all elements or just element at idx
   Examples:
   plist_member l int member - prints all elements and list size
   plist_member l int member 2 - prints the third element in the list (if exists) and list size
end

#
# std::map and std::multimap
#

define pmap
   if $argc == 0
       help pmap
   else
       set $tree = $arg0
       set $i = 0
       set $node = $tree._M_t._M_impl._M_header._M_left
       set $end = $tree._M_t._M_impl._M_header
       set $tree_size = $tree._M_t._M_impl._M_node_count
       if $argc == 1
           printf "Map "
           whatis $tree
           printf "Use pmap to see the elements in the map.\n"
       end
       if $argc == 3
           while $i < $tree_size
               set $value = (void *)($node + 1)
               printf "elem[%u].left: ", $i
               p *($arg1*)$value
               set $value = $value + sizeof($arg1)
               printf "elem[%u].right: ", $i
               p *($arg2*)$value
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
       end
       if $argc == 4
           set $idx = $arg3
           set $ElementsFound = 0
           while $i < $tree_size
               set $value = (void *)($node + 1)
               if *($arg1*)$value == $idx
                   printf "elem[%u].left: ", $i
                   p *($arg1*)$value
                   set $value = $value + sizeof($arg1)
                   printf "elem[%u].right: ", $i
                   p *($arg2*)$value
                   set $ElementsFound++
               end
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
           printf "Number of elements found = %u\n", $ElementsFound
       end
       if $argc == 5
           set $idx1 = $arg3
           set $idx2 = $arg4
           set $ElementsFound = 0
           while $i < $tree_size
               set $value = (void *)($node + 1)
               set $valueLeft = *($arg1*)$value
               set $valueRight = *($arg2*)($value + sizeof($arg1))
               if $valueLeft == $idx1 && $valueRight == $idx2
                   printf "elem[%u].left: ", $i
                   p $valueLeft
                   printf "elem[%u].right: ", $i
                   p $valueRight
                   set $ElementsFound++
               end
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
           printf "Number of elements found = %u\n", $ElementsFound
       end
       printf "Map size = %u\n", $tree_size
   end
end

document pmap
   Prints std::map or std::multimap information. Works for std::multimap as well.
   Syntax: pmap : Prints map size, if T defined all elements or just element(s) with val(s)
   Examples:
   pmap m - prints map size and definition
   pmap m int int - prints all elements and map size
   pmap m int int 20 - prints the element(s) with left-value = 20 (if any) and map size
   pmap m int int 20 200 - prints the element(s) with left-value = 20 and right-value = 200 (if any) and map size
end

define pmap_member
   if $argc == 0
       help pmap_member
   else
       set $tree = $arg0
       set $i = 0
       set $node = $tree._M_t._M_impl._M_header._M_left
       set $end = $tree._M_t._M_impl._M_header
       set $tree_size = $tree._M_t._M_impl._M_node_count
       if $argc == 1
           printf "Map "
           whatis $tree
           printf "Use pmap to see the elements in the map.\n"
       end
       if $argc == 5
           while $i < $tree_size
               set $value = (void *)($node + 1)
               printf "elem[%u].left: ", $i
               p (*($arg1*)$value).$arg2
               set $value = $value + sizeof($arg1)
               printf "elem[%u].right: ", $i
               p (*($arg3*)$value).$arg4
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
       end
       if $argc == 6
           set $idx = $arg5
           set $ElementsFound = 0
           while $i < $tree_size
               set $value = (void *)($node + 1)
               if *($arg1*)$value == $idx
                   printf "elem[%u].left: ", $i
                   p (*($arg1*)$value).$arg2
                   set $value = $value + sizeof($arg1)
                   printf "elem[%u].right: ", $i
                   p (*($arg3*)$value).$arg4
                   set $ElementsFound++
               end
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
           printf "Number of elements found = %u\n", $ElementsFound
       end
       printf "Map size = %u\n", $tree_size
   end
end

document pmap_member
   Prints std::map or std::multimap information. Works for std::multimap as well.
   Syntax: pmap : Prints map size, if T defined all elements or just element(s) with val(s)
   Examples:
   pmap_member m class1 member1 class2 member2 - prints class1.member1 : class2.member2
   pmap_member m class1 member1 class2 member2 lvalue - prints class1.member1 : class2.member2 where class1 == lvalue
end

#
# std::set and std::multiset
#

define pset
   if $argc == 0
       help pset
   else
       set $tree = $arg0
       set $i = 0
       set $node = $tree._M_t._M_impl._M_header._M_left
       set $end = $tree._M_t._M_impl._M_header
       set $tree_size = $tree._M_t._M_impl._M_node_count
       if $argc == 1
           printf "Set "
           whatis $tree
           printf "Use pset to see the elements in the set.\n"
       end
       if $argc == 2
           while $i < $tree_size
               set $value = (void *)($node + 1)
               printf "elem[%u]: ", $i
               p *($arg1*)$value
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
       end
       if $argc == 3
           set $idx = $arg2
           set $ElementsFound = 0
           while $i < $tree_size
               set $value = (void *)($node + 1)
               if *($arg1*)$value == $idx
                   printf "elem[%u]: ", $i
                   p *($arg1*)$value
                   set $ElementsFound++
               end
               if $node._M_right != 0
                   set $node = $node._M_right
                   while $node._M_left != 0
                       set $node = $node._M_left
                   end
               else
                   set $tmp_node = $node._M_parent
                   while $node == $tmp_node._M_right
                       set $node = $tmp_node
                       set $tmp_node = $tmp_node._M_parent
                   end
                   if $node._M_right != $tmp_node
                       set $node = $tmp_node
                   end
               end
               set $i++
           end
           printf "Number of elements found = %u\n", $ElementsFound
       end
       printf "Set size = %u\n", $tree_size
   end
end

document pset
   Prints std::set or std::multiset information. Works for std::multiset as well.
   Syntax: pset : Prints set size, if T defined all elements or just element(s) having val
   Examples:
   pset s - prints set size and definition
   pset s int - prints all elements and the size of s
   pset s int 20 - prints the element(s) with value = 20 (if any) and the size of s
end

#
# std::dequeue
#

define pdequeue
   if $argc == 0
       help pdequeue
   else
       set $size = 0
       set $start_cur = $arg0._M_impl._M_start._M_cur
       set $start_last = $arg0._M_impl._M_start._M_last
       set $start_stop = $start_last
       while $start_cur != $start_stop
           p *$start_cur
           set $start_cur++
           set $size++
       end
       set $finish_first = $arg0._M_impl._M_finish._M_first
       set $finish_cur = $arg0._M_impl._M_finish._M_cur
       set $finish_last = $arg0._M_impl._M_finish._M_last
       if $finish_cur < $finish_last
           set $finish_stop = $finish_cur
       else
           set $finish_stop = $finish_last
       end
       while $finish_first != $finish_stop
           p *$finish_first
           set $finish_first++
           set $size++
       end
       printf "Dequeue size = %u\n", $size
   end
end

document pdequeue
   Prints std::dequeue information.
   Syntax: pdequeue : Prints dequeue size, if T defined all elements
   Deque elements are listed "left to right" (left-most stands for front and right-most stands for back)
   Example:
   pdequeue d - prints all elements and size of d
end

#
# std::stack
#

define pstack
   if $argc == 0
       help pstack
   else
       set $start_cur = $arg0.c._M_impl._M_start._M_cur
       set $finish_cur = $arg0.c._M_impl._M_finish._M_cur
       set $size = $finish_cur - $start_cur
        set $i = $size - 1
        while $i >= 0
            p *($start_cur + $i)
            set $i--
        end
       printf "Stack size = %u\n", $size
   end
end

document pstack
   Prints std::stack information.
   Syntax: pstack : Prints all elements and size of the stack
   Stack elements are listed "top to buttom" (top-most element is the first to come on pop)
   Example:
   pstack s - prints all elements and the size of s
end

#
# std::queue
#

define pqueue
   if $argc == 0
       help pqueue
   else
       set $start_cur = $arg0.c._M_impl._M_start._M_cur
       set $finish_cur = $arg0.c._M_impl._M_finish._M_cur
       set $size = $finish_cur - $start_cur
        set $i = 0
        while $i < $size
            p *($start_cur + $i)
            set $i++
        end
       printf "Queue size = %u\n", $size
   end
end

document pqueue
   Prints std::queue information.
   Syntax: pqueue : Prints all elements and the size of the queue
   Queue elements are listed "top to bottom" (top-most element is the first to come on pop)
   Example:
   pqueue q - prints all elements and the size of q
end

#
# std::priority_queue
#

define ppqueue
   if $argc == 0
       help ppqueue
   else
       set $size = $arg0.c._M_impl._M_finish - $arg0.c._M_impl._M_start
       set $capacity = $arg0.c._M_impl._M_end_of_storage - $arg0.c._M_impl._M_start
       set $i = $size - 1
       while $i >= 0
           p *($arg0.c._M_impl._M_start + $i)
           set $i--
       end
       printf "Priority queue size = %u\n", $size
       printf "Priority queue capacity = %u\n", $capacity
   end
end

document ppqueue
   Prints std::priority_queue information.
   Syntax: ppqueue : Prints all elements, size and capacity of the priority_queue
   Priority_queue elements are listed "top to buttom" (top-most element is the first to come on pop)
   Example:
   ppqueue pq - prints all elements, size and capacity of pq
end

#
# std::bitset
#

define pbitset
   if $argc == 0
       help pbitset
   else
        p /t $arg0._M_w
   end
end

document pbitset
   Prints std::bitset information.
   Syntax: pbitset : Prints all bits in bitset
   Example:
   pbitset b - prints all bits in b
end

#
# std::string
#

define pstring
   if $argc == 0
       help pstring
   else
       printf "String \t\t\t= \"%s\"\n", $arg0._M_data()
       printf "String size/length \t= %u\n", $arg0._M_rep()._M_length
       printf "String capacity \t= %u\n", $arg0._M_rep()._M_capacity
       printf "String ref-count \t= %d\n", $arg0._M_rep()._M_refcount
   end
end

document pstring
   Prints std::string information.
   Syntax: pstring
   Example:
   pstring s - Prints content, size/length, capacity and ref-count of string s
end

#
# std::wstring
#

define pwstring
   if $argc == 0
       help pwstring
   else
       call printf("WString \t\t= \"%ls\"\n", $arg0._M_data())
       printf "WString size/length \t= %u\n", $arg0._M_rep()._M_length
       printf "WString capacity \t= %u\n", $arg0._M_rep()._M_capacity
       printf "WString ref-count \t= %d\n", $arg0._M_rep()._M_refcount
   end
end

document pwstring
   Prints std::wstring information.
   Syntax: pwstring
   Example:
   pwstring s - Prints content, size/length, capacity and ref-count of wstring s
end

#
# C++ related beautifiers (optional)
#

set print pretty on
set print object on
set print static-members on
set print vtbl on
set print demangle on
set demangle-style gnu-v3
set print sevenbit-strings off

################## End of Script #####################

Since I do not have .gdbinit in my home folder, I create one, copy the whole script to it, then run a simple sample program.

Breakpoint 1, main () at stl_vector.cpp:15
(gdb) pvector
Prints std::vector information.
Syntax: pvector
Note: idx, idx1 and idx2 must be in acceptable range [0...size()-1].
Examples:
pvector v - Prints vector content, size, capacity and T typedef
pvector v 0 - Prints element[idx] from vector
pvector v 1 2 - Prints elements in range [idx1..idx2] from vector
(gdb) pvector iv
elem[0]: $1 = 10
elem[1]: $2 = 20
elem[2]: $3 = 30
Vector size = 3
Vector capacity = 4
Element type = int *
(gdb) pvector iv 0
elem[0]: $4 = 10
Vector size = 3
Vector capacity = 4
Element type = int *
(gdb)

Pretty amazing!

Bing Xia's Blog

Monday, July 5, 2010

STL and GDB

How to generate g++ symbol file

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