I am just trying to understand how does lauterbach trace32 prints registers with r command. Also how does it set breakpoints. Basically how does trace32 extract/modifies live register values? Any documentation/ source scripts to understand the sequence?
Related
How do I print the local variables in GDB every "next" or "step" command?
Is there a way instead of writing "info locals" every time?
If you can use GDB TUI mode, that's probably best. See this answer.
If you can't use TUI for some reason, this should also work:
# put this into ~/.gdbinit:
define hook-next
info locals
end
More info on hooking commands here.
I am trying to write a Python script for GDB to trace a function.
The idea is to set a breakpoint on an address location, let the program run and then, when it breaks, log to file registers, vectors and stack and find out what address the next instruction will be, set a breakpoint on that location and rinse and repeat.
I read through the documentation and I'm pretty confident registers, vectors and memory locations can be easily dumped. The actual problem is finding what the next instruction location will be as it requires to analyze the disassembly of the current instruction to determine where the next breakpoint should be placed.
Update
I am doing all this without using stepi or nexti because the target I'm debugging works only with hardware breakpoints and as far as I know those commands use software breakpoints to break at the next instruction
Is there anything like that in GDB?
Yes, you can do this in gdb. Rather than trying to set a breakpoint on the next instruction, you can instead use the si command to single-step to the next instruction.
As we know, during gdb debugging, command 'info reg' can be used to show register
status. But in some cases, if gdb start with x86 binary, which may jumped into a
memory block which contains X64-32 instructions, how can I get R9-R15 in step by
step debugging?
info register
set architecture i386:X64-32
I tried 'set architecture', but it doesn't work. Thanks in advance!
2 years later, I finally found that should set architecture i386:x64-32 BEFORE target program starting to run.
I am using GDB along with a JTAG device, an Abatron BDI2000, to debug a programs running on a Motorola M68332.
The 68332 does not have any hardware breakpoint registers. It has very primitive debugging features.
The build tools do not generate 'elf' files, so no symbols for GDB to use.
Also the program I'm debugging is running in Flash.
In fact the 68332 has only one debug instruction, ti. ti by itself steps to the next assembly instruction. ti xxx steps until the address xxx is reached. [Yes, this is caveman days, cold hammer and chisel :)]
I am able to use GDB with target remote to connect to the BDI2000 and issue the GDB commands 'nexti'. Due to the limitations of the 68332, 'stepi' is equivalent to 'nexti'.
Single stepping is only command available.
The monitor command 'monitor ti ' states change the program counter to and step.
If one uses a 'monitor' command that changes the registers, then GDB does not know about the command and its register cache become out of sync. I have created GDB functions which have the GDB command 'flushregs' at the end of each of them. This marks the register cache dirty. The GDB command will fetch a new set of registers.
I would like to create a symbol table file for debugging, but have not found any documentation on the GDB symbol file format.
Are there alternatives to what I have setup?
I do have a RAM overlay for the Flash area. Would this allow software breakpoints?
Thanks in advance for any advice.
I found I can use 'convenience' variables as a substitute for symbols, since I'm not using ever symbol in the program all at once.
set $Symbol=(unsigned int*)<address>
Each 'Symbol' is declared a pointer to an unsigned int at an address. One can put these statements in .gdbinit, and add to them over time.
One can then state
break $Symbol
I show a GDB command function that can be passed one of these 'convenience' variables in the question linked below.
How do I write a GDB function to make a comparison to the program counter
I'm writing a GDB script to walk the stack and inspect certain local variables only if the function running at that stack level is a specific one. How can I programatically check which function is running at each level? "backtrace" shows what I want. I just need it in a variable.
You can do what you want in GDB 7.3, which has Python scripting and exposed stack frame info to the Python interpreter.