How configure xtensa-lx106-elf to compile c++ code for esp8266 using nonos-sdk?

Question

I'm having difficulties to compile c++ code with xtensa-lx106-elf.

The manufacture of the chip I'm using (esp8266) provides a sdk (nonos-sdk). One of the libraries in this sdk implements functions to allocate memory in the chip: os_malloc, os_realloc, etc.

When compiling c code, everything works fine. When compiling c++, object files are generated successfully but I get a lot of error messages from the linker, complaining about undefined references to abort, free, malloc and a very odd one to __gxx_personality_v0.

My make file was created using cmake. Bellow the options that I use with the compiler.

target_include_directories( 
  ${elf_file}

  PUBLIC
  src/
  inc/
  /opt/esp-open-sdk/sdk/driver_lib/include/
  /opt/esp-open-sdk/sdk/include/
  )

target_compile_options(
  ${elf_file}

  PUBLIC
  -mlongcalls -c -std=c++11 -v
  )

target_link_libraries( 
  ${elf_file}

  PUBLIC

  -L/opt/esp-open-sdk/sdk/lib
  -L/opt/esp-open-sdk/sdk/ld
  -Teagle.app.v6.ld

  -nostdlib

  -Wl,--start-group
    -lmain -lhal -lnet80211 -lcrypto -lupgrade -lwpa -llwip -lpp -lphy -v
  -Wl,--end-group

  -ldriver
  -lcirom
  -lgcc
  )

Compiler errors:

CMakeFiles/MasterSPI-esp8266.elf.dir/src/main.cpp.o:(.eh_frame+0x12): undefined reference to `__gxx_personality_v0'
CMakeFiles/MasterSPI-esp8266.elf.dir/src/spi.cpp.o:(.eh_frame+0x12): undefined reference to `__gxx_personality_v0'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2.o):(.literal+0x8): undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2.o): In function `execute_cfa_program':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2.c:1212: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2.o): In function `read_encoded_value_with_base':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-pe.h:252: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2.o): In function `execute_stack_op':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2.c:905: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2.o): In function `uw_update_context_1':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2.c:1420: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2.o):/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2.c:1560: more undefined references to `abort' follow
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o):(.literal+0x20): undefined reference to `malloc'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o):(.literal+0x24): undefined reference to `free'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `size_of_encoded_value':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-pe.h:88: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `read_encoded_value_with_base':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-pe.h:257: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `base_from_object':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:256: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `start_fde_sort':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:409: undefined reference to `malloc'
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:412: undefined reference to `malloc'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `end_fde_sort':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:575: undefined reference to `abort'
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:590: undefined reference to `free'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `__register_frame':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:118: undefined reference to `malloc'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `__register_frame_table':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:156: undefined reference to `malloc'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `__deregister_frame_info_bases':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:200: undefined reference to `free'
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:216: undefined reference to `abort'
/opt/esp-open-sdk/sdk/lib/libgcc.a(unwind-dw2-fde.o): In function `__deregister_frame':
/home/wjg/Repo/esp-open-sdk-20170622/crosstool-NG/.build/src/gcc-4.8.5/libgcc/unwind-dw2-fde.c:231: undefined reference to `free'

Something that catch my attention is that it seems the linker is trying to find many files in the path: "/home/wjg/Repo/" and I can confirm it doesn't exist in my computer. Can't understand this behavior.

---

Tools info:

OS: Ubuntu 16.04LTS

Compiler: xtensa-lx106-elf-g++ (crosstool-NG crosstool-ng-1.22.0-60-g37b07f6) 4.8.5

CMake: cmake version 3.12.0-rc3

nonos-sdk: 2.2.1

Answer 1

Maybe you forgot to link against the C++ libraries? These are the libraries I use during linking my C++ files on the ESP8266:

-lhal -lphy -lpp -lnet80211 -llwip2 -lwpa -lcrypto -lmain -lwps \
-laxtls -lespnow -lsmartconfig -lairkiss -lwpa2 -lstdc++ -lm -lc -lgcc

Especially the -lstdc++ is important! Try to add those libraries to your makefile!

Answer 2

You are probably importing stdlib or trying to use malloc, free, and some other stdlib functions, which are not available in this SDK.

Rename all places that use malloc() with os_zalloc() and try again.

This usually happens when the sources point to, or import, standard libraries. Your compiler flags tell you why: -nostdlib