Can't step assembler code that in user-defined section

["redriver jiang" <jiangpeople at gmail dot com>]

Hi all:

Recently I using the arm-gdb to debug my arm code, and find some
"bugs" in arm-gdb.One of my assembler source has 3
sections-----".init",".text",".fini", these 3 sections are not
adjacent after link, the ".init" section comes first, then the ".text"
section ,and finally the ".fini". I set a breakpoint in the line of
the ".init" section, and used "r" command in arm-gdb then it stop in
correct position, then I typed "step" command attempting that it will
stops in the next line, but gdb warned the following messages:
"Cannot find bounds of current function,Single stepping until exit
from function __rest,which has no line number information."

I tracked the execution of the gdb for a while, and finally find the
problem. In dbxread.c, there is a function "read_dbx_symtab", this
function initialize the the "psymtabs" member of global var
"object_files"(and also other
functions, but I don't care), the psymtabs chain is created from the
debug information in the final exectuable file, mainly the stabs debug
inforamtion whose type is "N_SO". The psymtabs's textlow member is
determided by this "N_SO" stabs's value, which is this file's inital
".text" section address in the final executable file. For example, the
final address of this 3 sections shows in follow:

.init:  0x0  - 0x200
.text:  0x500 - 0x600
.fini:  0x900   - 0xC00

then the textlow and texthigh member of the psymtabs node in psymtabs
chain of this assemble file is 0x500 and 0x600! I made a change in
"read_dbx_symtab", and the textlow and texthigh is 0x0 and 0xC00, but
when I set a breakpoint in the ".fini" section soure line and use
"step" after break, there comes an another problem, the gdb executes
this assemble's code, but it displays other's assembler file's
contents.This assembler's code range is 0x700-0x800.

   For the situation of single assembler file containing several
sections which are not adjacent, I suggest that during psymtabs
creating, there should be
multiple psymtabs node for individual sections, with which sharing a file(their
"filename" member is same).

 The gdb version is :

GNU gdb 6.6
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This GDB was configured as "--host=i686-pc-cygwin --target=arm"



redriver