I tried to build a gdb for esp32 that works with qemu, but after many attempt, I didn't manage. All my attempts leaded me to the following error message after connecting to the remote target: Remote 'g' packet reply is too long.
Right now I am using the prebuilt version from Ebiroll: https://github.com/Ebiroll/qemu_esp32/blob/master/bin/xtensa-esp32-elf-gdb but I would like to use a newer gdb version than 7.10, did anyone had success with this?
Here is how I built gdb:
git clone --depth 1 --branch esp-2021r2-gdb https://github.com/espressif/binutils-gdb.git
cd binutils-gdb
mkdir -p build
cd build
../configure --without-guile --host=x86_64-pc-linux-gnu --target=xtensa-esp32-elf --disable-werror
make
make install
(note from this branch the patch to apply from the Zephyr project, as described here https://github.com/Ebiroll/qemu_esp32#qemu-esp32, seems to already be included)
I also tried by applying the following patch (no success):
curl -L https://raw.githubusercontent.com/Ebiroll/gdb/master/gdb/xtensa-config.c.qemu --output binutils-gdb/gdb/xtensa-config.c
or patching qemu to fix the value of num_regs (tried 104 and 172, also no success).