I'm working on an ESP8266 project where I need to override thepostmortem_report() function in a way that ensures my custom implementation is called instead of the original one. The original function is defined asstatic in a C file, which means it has internal linkage and is only visible within that file.

To achieve this, I attempted to use the linker flag-Wl,--wrap=postmortem_report to wrap the function and redirect calls to__wrap_postmortem_report, which I have defined in my C++ code. Here’s the relevant code:

Original Function (in C file):

extern"C"staticvoidpostmortem_report(uint32_t sp_dump) {// Original implementation}

My Custom Wrapper (in C++ file):

extern"C"void__wrap_postmortem_report(uint32_t sp_dump) {// Custom implementation}

Linker Flag in Build System:

"buildPreferences": [    ["build.extra_flags","-Wl,--wrap=postmortem_report"    ]

The Problem:

Despite setting everything up as described, it seems that my__wrap_postmortem_report() function isnot being called whenpostmortem_report() is invoked. Instead, the originalpostmortem_report() is still executed.

What I've Tried:

• Verified that the-Wl,--wrap=postmortem_report flag is correctly passed to the linker:

"xtensa-lx106-elf-g++" ... -Wl,--wrap=postmortem_report

• Ensured that__wrap_postmortem_report has external linkage by usingextern "C".
• Tried different compiler optimizations (-O0) to rule out issues related to inlining or optimization.
• Checked for symbol conflicts to ensure there’s only onepostmortem_report function in the project (thestatic one).
• Examined the linker steps for any overrides but didn’t find anything that could interfere with function wrapping.

Questions:

1. Is there something specific about the ESP8266 toolchain that might cause this wrapping mechanism to fail?
2. Could thestatic keyword in the original function be interfering with the wrapping process, despite the linker flag?
3. Are there any additional steps or considerations I should take to ensure that the__wrap_postmortem_report() function is called instead of the original?

The original code in thecore_esp8266_postmortem.cpp file references thepostmortem_report() in the assembly as well:

asm(".section     .text.__wrap_system_restart_local,\"ax\",@progbits\n\t"".literal_position\n\t"".align       4\n\t"".global      __wrap_system_restart_local\n\t"".type        __wrap_system_restart_local, @function\n\t""\n""__wrap_system_restart_local:\n\t""mov          a2,     a1\n\t""j            postmortem_report\n\t"".size __wrap_system_restart_local, .-__wrap_system_restart_local\n\t");

Any insights or suggestions on what might be going wrong and how to fix it would be greatly appreciated!