enhanced stack trace decoder for ESP8266

[pljakobs]

plus minor fixes on the ESP32 side (mostly for consistency). This also updates gdb_hooks to include the register dump into the portion the user is to copy in to the stack trace decoder

• decoder now includes the register dump, showing the different memory areas color coded to allow quick distinction of code/data addresses
• if possible shows a symbol / code line decode of addresses in the register file
• shows c/c++ context from the source file
• shows assembly context (only after the offending instruction)
• provides the same color coded addresses in the hex stack trace
• shows a list of functions on the stack
• shows a list of data addresses / labels on the stack

The output, when used interactively, uses a pager and the input now requires to mark the end of the input by ^D (what was necessary to not get mixed lines in the output)

I did change the gdb_hooks.cpp file to

• define the FSTRING values in a central place but use them in both the gdbstub_exception_handler_flash() and dumpExceptionInfo() functions. This might not be the most elegant way, but with the ======= lines only wrapping around the actual stack dump, the guidance is confusing for the user and they would probably not copy the register file

[what-the-diff]

PR Summary

• Improved Code Comprehension in decode-stacktrace.py:

  • Introduced CANARY_VALUES, a new constant to replace hard-coded values, improving readability.
  • A new function, colorizeHex was added for color-coding hex values in the output, making it easier to dechiper.
  • Upgraded how disassembly operates by employing getAddrColor to color-code addresses.
  • Implemented checks to spew out warnings when non-code memory gets executed, enhancing safety.

• Code Optimization in gdb_hooks.cpp:

  • Exchanged recurring string definitions with DEFINE_PSTR_LOCAL, refining the overall code structure, and promoting cleanliness.
  • Performing modifications in debug_print_stack and debug_crash_callback functions to leverage the new string definitions, thereby diminishing redundancy.
  • Ensured a steady print of instructions and separators when exceptions occur, improving consistency in outputs.