Weird clangd LSP issue

[LukaszMoskala]

Hi,

Thank you for maintaining this great platform.

I'm not sure if that's the right place for this issue, but this doesn't happen when using other platform (for example AVR). If that's not the right place, feel free to close this issue and direct me where should I open it.

I use neovim with lazyvim + clangd LSP.

Steps to reproduce:

Create a new project:

pio project init --board nanoatmega328new --ide vim

Create src/main.cpp with following content:

#include <Arduino.h>
void setup() {}
void loop() {}

Build database:

pio run -t compiledb

Run clangd:

clangd --check=src/main.cpp

Complete output of clangd:

I[14:28:15.168] clangd version 20.1.6
I[14:28:15.168] Features: linux
I[14:28:15.168] PID: 54418
I[14:28:15.168] Working directory: /home/lmoskala/pio_clangd_test/avr
I[14:28:15.168] argv[0]: clangd
I[14:28:15.168] argv[1]: --check=src/main.cpp
I[14:28:15.168] Entering check mode (no LSP server)
I[14:28:15.168] Testing on source file /home/lmoskala/pio_clangd_test/avr/src/main.cpp
I[14:28:15.168] Loading compilation database...
I[14:28:15.168] Loaded compilation database from /home/lmoskala/pio_clangd_test/avr/compile_commands.json
I[14:28:15.168] Compile command from CDB is: [/home/lmoskala/pio_clangd_test/avr] /home/lmoskala/.platformio/packages/toolchain-atmelavr/bin/avr-g++ --target=avr --driver-mode=g++ -o .pio/build/nanoatmega328new/src/main.cpp.o -c -fno-exceptions -fno-threadsafe-statics -fpermissive -std=gnu++11 -mmcu=atmega328p -Os -Wall -ffunction-sections -fdata-sections -flto -DPLATFORMIO=60118 -DARDUINO_AVR_NANO -DF_CPU=16000000L -DARDUINO_ARCH_AVR -DARDUINO=10808 -Iinclude -Isrc -I/home/lmoskala/.platformio/packages/framework-arduino-avr/cores/arduino -I/home/lmoskala/.platformio/packages/framework-arduino-avr/variants/eightanaloginputs -resource-dir=/usr/lib/clang/20 -- /home/lmoskala/pio_clangd_test/avr/src/main.cpp
I[14:28:15.169] Parsing command...
I[14:28:15.169] internal (cc1) args are: -cc1 -triple avr -fsyntax-only -flto=full -flto-unit -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name main.cpp -mrelocation-model static -mframe-pointer=all -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -fno-use-init-array -fno-use-cxa-atexit -target-cpu atmega328p -debugger-tuning=gdb -fdebug-compilation-dir=/home/lmoskala/pio_clangd_test/avr -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/home/lmoskala/pio_clangd_test/avr -resource-dir /usr/lib/clang/20 -D PLATFORMIO=60118 -D ARDUINO_AVR_NANO -D F_CPU=16000000L -D ARDUINO_ARCH_AVR -D ARDUINO=10808 -I include -I src -I /home/lmoskala/.platformio/packages/framework-arduino-avr/cores/arduino -I /home/lmoskala/.platformio/packages/framework-arduino-avr/variants/eightanaloginputs -internal-isystem /home/lmoskala/.platformio/packages/toolchain-atmelavr/bin/../lib/gcc/avr/7.3.0/../../../../avr/include -Os -Wall -std=gnu++11 -fdeprecated-macro -ferror-limit 19 -fgnuc-version=4.2.1 -fno-threadsafe-statics -fskip-odr-check-in-gmf -vectorize-loops -vectorize-slp -no-round-trip-args -faddrsig -x c++ /home/lmoskala/pio_clangd_test/avr/src/main.cpp
I[14:28:15.169] Building preamble...
I[14:28:15.181] Built preamble of size 447500 for file /home/lmoskala/pio_clangd_test/avr/src/main.cpp version null in 0.01 seconds
I[14:28:15.181] Indexing headers...
I[14:28:15.192] Building AST...
I[14:28:15.194] Indexing AST...
I[14:28:15.194] Building inlay hints
I[14:28:15.194] Building semantic highlighting
I[14:28:15.194] Testing features at each token (may be slow in large files)
I[14:28:15.196] All checks completed, 0 errors

It reports no errors, as expected.

Now, replace platformio.ini with:

[env:rpipico]
platform = https://github.com/maxgerhardt/platform-raspberrypi.git
board = rpipico
framework = arduino
board_build.core = earlephilhower

And run again

pio run -t compiledb
clangd --check=src/main.cpp

Which returns:

I[14:29:45.331] clangd version 20.1.6
I[14:29:45.331] Features: linux
I[14:29:45.331] PID: 54901
I[14:29:45.331] Working directory: /home/lmoskala/pio_clangd_test/pico
I[14:29:45.331] argv[0]: clangd
I[14:29:45.331] argv[1]: --check=src/main.cpp
I[14:29:45.331] Entering check mode (no LSP server)
I[14:29:45.331] Testing on source file /home/lmoskala/pio_clangd_test/pico/src/main.cpp
I[14:29:45.331] Loading compilation database...
I[14:29:45.332] Loaded compilation database from /home/lmoskala/pio_clangd_test/pico/compile_commands.json
I[14:29:45.332] Compile command from CDB is: [/home/lmoskala/pio_clangd_test/pico] /home/lmoskala/.platformio/packages/toolchain-rp2040-earlephilhower/bin/arm-none-eabi-g++ --target=arm-none-eabi --driver-mode=g++ -o .pio/build/rpipico/src/main.cpp.o -c -fno-exceptions -fno-rtti -std=gnu++17 -Os -Werror=return-type -Wno-psabi -ffunction-sections -fdata-sections -march=armv6-m -mcpu=cortex-m0plus -mthumb -iprefix/home/lmoskala/.platformio/packages/framework-arduinopico -iwithprefixbefore/include/rp2040 -iwithprefixbefore/include/rp2040/pico_base -iwithprefixbefore/pico-sdk/src/rp2040/hardware_regs/include -iwithprefixbefore/pico-sdk/src/rp2040/hardware_structs/include -iwithprefixbefore/pico-sdk/src/rp2040/pico_platform/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_btstack/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_cyw43_arch/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_cyw43_driver/include -iwithprefixbefore/pico-sdk/lib/cyw43-driver/src -iwithprefixbefore/pico-sdk/lib/btstack/src -iwithprefixbefore/pico-sdk/lib/btstack/3rd-party/bluedroid/decoder/include -iwithprefixbefore/pico-sdk/lib/btstack/3rd-party/bluedroid/encoder/include -iwithprefixbefore/pico-sdk/lib/btstack/3rd-party/yxml -iwithprefixbefore/pico-sdk/lib/btstack/platform/embedded -iwithprefixbefore/pico-sdk/src/rp2_common/cmsis/stub/CMSIS/Device/RP2040/Include -iwithprefixbefore/cores/rp2040/api/deprecated-avr-comp -iwithprefixbefore/pico-sdk/lib/tinyusb/src -iwithprefixbefore/pico-sdk/src/boards/include -iwithprefixbefore/pico-sdk/src/common/hardware_claim/include -iwithprefixbefore/pico-sdk/src/common/pico_base/include -iwithprefixbefore/pico-sdk/src/common/pico_base_headers/include -iwithprefixbefore/pico-sdk/src/common/pico_binary_info/include -iwithprefixbefore/pico-sdk/src/common/pico_bit_ops/include -iwithprefixbefore/pico-sdk/src/common/pico_divider/include -iwithprefixbefore/pico-sdk/src/common/pico_stdlib/include -iwithprefixbefore/pico-sdk/src/common/pico_sync/include -iwithprefixbefore/pico-sdk/src/common/pico_time/include -iwithprefixbefore/pico-sdk/src/common/pico_usb_reset_interface/include -iwithprefixbefore/pico-sdk/src/common/pico_util/include -iwithprefixbefore/pico-sdk/src/common/pico_stdlib_headers/include -iwithprefixbefore/pico-sdk/src/common/pico_usb_reset_interface_headers/include -iwithprefixbefore/pico-sdk/src/rp2_common/boot_bootrom_headers/include -iwithprefixbefore/pico-sdk/src/rp2_common/cmsis/include -iwithprefixbefore/pico-sdk/src/rp2_common/cmsis/stub/CMSIS/Core/Include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_adc/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_base/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_boot_lock/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_clocks/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_divider/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_dma/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_exception/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_flash/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_gpio/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_i2c/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_interp/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_irq/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_rtc/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_pio/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_pll/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_pwm/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_resets/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_spi/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_sync/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_sync_spin_lock/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_timer/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_uart/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_vreg/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_watchdog/include -iwithprefixbefore/pico-sdk/src/rp2_common/hardware_xosc/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_aon_timer/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_async_context/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_bootrom/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_double/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_fix/rp2040_usb_device_enumeration/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_flash/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_float/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_int64_ops/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_lwip/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_multicore/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_platform/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_platform_compiler/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_platform_sections/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_platform_panic/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_printf/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_runtime/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_runtime_init/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_rand/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_stdio/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_stdio_uart/include -iwithprefixbefore/pico-sdk/src/rp2_common/pico_unique_id/include -iwithprefixbefore/pico-sdk/lib/lwip/src/include -DPLATFORMIO=60118 -DARDUINO_RASPBERRY_PI_PICO -DARDUINO_ARCH_RP2040 -DUSBD_MAX_POWER_MA=250 -DARDUINO=10810 -DARDUINO_ARCH_RP2040 -DF_CPU=133000000L "-DBOARD_NAME=\"rpipico\"" -DARM_MATH_CM0_FAMILY -DARM_MATH_CM0_PLUS -DTARGET_RP2040 -DPICO_RP2040=1 -DPICO_FLASH_SIZE_BYTES=2097152 -DFILE_COPY_CONSTRUCTOR_SELECT=FILE_COPY_CONSTRUCTOR_PUBLIC -DUSE_UTF8_LONG_NAMES=1 -DDISABLE_FS_H_WARNING=1 -DCFG_TUSB_MCU=OPT_MCU_RP2040 -DUSB_VID=0x2E8A -DUSB_PID=0x000A -DUSBD_VID=0x2E8A -DUSBD_PID=0x000A "-DUSB_MANUFACTURER=\"Raspberry Pi\"" "-DUSB_PRODUCT=\"Pico\"" -DPICO_CYW43_ARCH_THREADSAFE_BACKGROUND=1 -DCYW43_LWIP=1 -DCYW43_PIO_CLOCK_DIV_DYNAMIC=1 -DLWIP_IPV4=1 -DLWIP_IGMP=1 -DLWIP_CHECKSUM_CTRL_PER_NETIF=1 -DLWIP_IPV6=0 "-DARDUINO_VARIANT=\"rpipico\"" -Iinclude -Isrc -I/home/lmoskala/.platformio/packages/framework-arduinopico/cores/rp2040 -I/home/lmoskala/.platformio/packages/framework-arduinopico/cores/rp2040/api/deprecated -I/home/lmoskala/.platformio/packages/framework-arduinopico/cores/rp2040/api/deprecated-avr-comp -I/home/lmoskala/.platformio/packages/framework-arduinopico/include -I/home/lmoskala/.platformio/packages/framework-arduinopico/variants/rpipico -resource-dir=/usr/lib/clang/20 -- /home/lmoskala/pio_clangd_test/pico/src/main.cpp
I[14:29:45.332] Parsing command...
I[14:29:45.333] internal (cc1) args are: -cc1 -triple thumbv6m-unknown-none-eabi -fsyntax-only -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name main.cpp -mrelocation-model static -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -nostdsysteminc -target-cpu cortex-m0plus -target-feature +soft-float-abi -target-feature -crc -target-feature -dsp -target-feature -mve -target-feature -ras -target-feature -sb -target-feature -i8mm -target-feature -lob -target-feature -cdecp0 -target-feature -cdecp1 -target-feature -cdecp2 -target-feature -cdecp3 -target-feature -cdecp4 -target-feature -cdecp5 -target-feature -cdecp6 -target-feature -cdecp7 -target-feature -pacbti -target-feature -hwdiv-arm -target-feature -hwdiv -target-feature -vfp2 -target-feature -vfp2sp -target-feature -vfp3 -target-feature -vfp3d16 -target-feature -vfp3d16sp -target-feature -vfp3sp -target-feature -fp16 -target-feature -vfp4 -target-feature -vfp4d16 -target-feature -vfp4d16sp -target-feature -vfp4sp -target-feature -fp-armv8 -target-feature -fp-armv8d16 -target-feature -fp-armv8d16sp -target-feature -fp-armv8sp -target-feature -fullfp16 -target-feature -fp64 -target-feature -d32 -target-feature -neon -target-feature -dotprod -target-feature -fp16fml -target-feature -bf16 -target-feature -mve.fp -target-feature -fpregs -target-feature -crypto -target-feature -sha2 -target-feature -aes -target-feature +strict-align -target-abi aapcs -mfloat-abi soft -Wunaligned-access -debugger-tuning=gdb -fdebug-compilation-dir=/home/lmoskala/pio_clangd_test/pico -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/home/lmoskala/pio_clangd_test/pico -resource-dir /usr/lib/clang/20 -iprefix /home/lmoskala/.platformio/packages/framework-arduinopico -iwithprefixbefore /include/rp2040 -iwithprefixbefore /include/rp2040/pico_base -iwithprefixbefore /pico-sdk/src/rp2040/hardware_regs/include -iwithprefixbefore /pico-sdk/src/rp2040/hardware_structs/include -iwithprefixbefore /pico-sdk/src/rp2040/pico_platform/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_btstack/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_cyw43_arch/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_cyw43_driver/include -iwithprefixbefore /pico-sdk/lib/cyw43-driver/src -iwithprefixbefore /pico-sdk/lib/btstack/src -iwithprefixbefore /pico-sdk/lib/btstack/3rd-party/bluedroid/decoder/include -iwithprefixbefore /pico-sdk/lib/btstack/3rd-party/bluedroid/encoder/include -iwithprefixbefore /pico-sdk/lib/btstack/3rd-party/yxml -iwithprefixbefore /pico-sdk/lib/btstack/platform/embedded -iwithprefixbefore /pico-sdk/src/rp2_common/cmsis/stub/CMSIS/Device/RP2040/Include -iwithprefixbefore /cores/rp2040/api/deprecated-avr-comp -iwithprefixbefore /pico-sdk/lib/tinyusb/src -iwithprefixbefore /pico-sdk/src/boards/include -iwithprefixbefore /pico-sdk/src/common/hardware_claim/include -iwithprefixbefore /pico-sdk/src/common/pico_base/include -iwithprefixbefore /pico-sdk/src/common/pico_base_headers/include -iwithprefixbefore /pico-sdk/src/common/pico_binary_info/include -iwithprefixbefore /pico-sdk/src/common/pico_bit_ops/include -iwithprefixbefore /pico-sdk/src/common/pico_divider/include -iwithprefixbefore /pico-sdk/src/common/pico_stdlib/include -iwithprefixbefore /pico-sdk/src/common/pico_sync/include -iwithprefixbefore /pico-sdk/src/common/pico_time/include -iwithprefixbefore /pico-sdk/src/common/pico_usb_reset_interface/include -iwithprefixbefore /pico-sdk/src/common/pico_util/include -iwithprefixbefore /pico-sdk/src/common/pico_stdlib_headers/include -iwithprefixbefore /pico-sdk/src/common/pico_usb_reset_interface_headers/include -iwithprefixbefore /pico-sdk/src/rp2_common/boot_bootrom_headers/include -iwithprefixbefore /pico-sdk/src/rp2_common/cmsis/include -iwithprefixbefore /pico-sdk/src/rp2_common/cmsis/stub/CMSIS/Core/Include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_adc/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_base/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_boot_lock/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_clocks/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_divider/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_dma/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_exception/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_flash/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_gpio/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_i2c/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_interp/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_irq/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_rtc/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_pio/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_pll/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_pwm/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_resets/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_spi/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_sync/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_sync_spin_lock/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_timer/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_uart/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_vreg/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_watchdog/include -iwithprefixbefore /pico-sdk/src/rp2_common/hardware_xosc/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_aon_timer/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_async_context/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_bootrom/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_double/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_fix/rp2040_usb_device_enumeration/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_flash/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_float/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_int64_ops/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_lwip/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_multicore/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_platform/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_platform_compiler/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_platform_sections/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_platform_panic/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_printf/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_runtime/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_runtime_init/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_rand/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_stdio/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_stdio_uart/include -iwithprefixbefore /pico-sdk/src/rp2_common/pico_unique_id/include -iwithprefixbefore /pico-sdk/lib/lwip/src/include -D PLATFORMIO=60118 -D ARDUINO_RASPBERRY_PI_PICO -D ARDUINO_ARCH_RP2040 -D USBD_MAX_POWER_MA=250 -D ARDUINO=10810 -D ARDUINO_ARCH_RP2040 -D F_CPU=133000000L -D "BOARD_NAME=\"rpipico\"" -D ARM_MATH_CM0_FAMILY -D ARM_MATH_CM0_PLUS -D TARGET_RP2040 -D PICO_RP2040=1 -D PICO_FLASH_SIZE_BYTES=2097152 -D FILE_COPY_CONSTRUCTOR_SELECT=FILE_COPY_CONSTRUCTOR_PUBLIC -D USE_UTF8_LONG_NAMES=1 -D DISABLE_FS_H_WARNING=1 -D CFG_TUSB_MCU=OPT_MCU_RP2040 -D USB_VID=0x2E8A -D USB_PID=0x000A -D USBD_VID=0x2E8A -D USBD_PID=0x000A -D "USB_MANUFACTURER=\"Raspberry Pi\"" -D "USB_PRODUCT=\"Pico\"" -D PICO_CYW43_ARCH_THREADSAFE_BACKGROUND=1 -D CYW43_LWIP=1 -D CYW43_PIO_CLOCK_DIV_DYNAMIC=1 -D LWIP_IPV4=1 -D LWIP_IGMP=1 -D LWIP_CHECKSUM_CTRL_PER_NETIF=1 -D LWIP_IPV6=0 -D "ARDUINO_VARIANT=\"rpipico\"" -I include -I src -I /home/lmoskala/.platformio/packages/framework-arduinopico/cores/rp2040 -I /home/lmoskala/.platformio/packages/framework-arduinopico/cores/rp2040/api/deprecated -I /home/lmoskala/.platformio/packages/framework-arduinopico/cores/rp2040/api/deprecated-avr-comp -I /home/lmoskala/.platformio/packages/framework-arduinopico/include -I /home/lmoskala/.platformio/packages/framework-arduinopico/variants/rpipico -internal-isystem /home/lmoskala/.platformio/packages/toolchain-rp2040-earlephilhower/bin/../lib/clang-runtimes/arm-none-eabi/include/c++/v1 -internal-isystem /usr/lib/clang/20/include -internal-isystem /home/lmoskala/.platformio/packages/toolchain-rp2040-earlephilhower/bin/../lib/clang-runtimes/arm-none-eabi/include -Os -Werror=return-type -Wno-psabi -std=gnu++17 -fdeprecated-macro -ferror-limit 19 -fno-rtti -fno-signed-char -fgnuc-version=4.2.1 -fskip-odr-check-in-gmf -vectorize-loops -vectorize-slp -no-round-trip-args -faddrsig -x c++ /home/lmoskala/pio_clangd_test/pico/src/main.cpp
I[14:29:45.333] Building preamble...
I[14:29:45.401] Built preamble of size 3757704 for file /home/lmoskala/pio_clangd_test/pico/src/main.cpp version null in 0.07 seconds
I[14:29:45.401] Indexing headers...
E[14:29:45.524] [pp_file_not_found] Line 1: in included file: 'stdlib.h' file not found
I[14:29:45.524] Building AST...
I[14:29:45.527] Indexing AST...
I[14:29:45.527] Building inlay hints
I[14:29:45.527] Building semantic highlighting
I[14:29:45.527] Testing features at each token (may be slow in large files)
I[14:29:45.528] All checks completed, 1 errors

I'm not exactly sure why this happens. I kind of feel like this may be related to -iwithprefixbefore/... in output which doesn't look right to me. Also, using COMPILATIONDB_INCLUDE_TOOLCHAIN=True, causes clangd to not be able to find other platform-related includes like #include <FreeRTOS.h> while platformio itself still properly compiles the code. This seems related to platformio/platformio-core#5166.

I have no idea what I'm doing wrong or even in which project the problem is (here or in platformiocore)

Could anyone guide me in the right direction?
Thank you for your time

[earlephilhower]

P.IO must really be borikng the clang compile if it can't find gcc native headers. We use withprefixbefore for the SDK includes, it's a normal gcc option.

I'd suggest dumping the commands pio is calling in that compiledb stage and verifying they're correct and didn't produce any errors or warnings.

[LukaszMoskala]

Okay, by some miracle, I figured it out.

Adding --query-driver=/**/.platformio/**/bin/*-g++,/**/.platformio/**/bin/*-gcc to clangd in my neovim config helped and now it seems that it's working. Hopefully this helps someone in the future.