Could no set path of compiler

[zisi]

Describe the bug
I set the compiler by using:

set(STM32_TARGET_TRIPLET "arm-none-eabi")
set(STM32_TOOLCHAIN_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tools/gcc-arm-none-eabi-latest")

but the stm32-cmake uses the usr path to find compiler. Finally i change the stm32_gcc.cmake

find_program(CMAKE_C_COMPILER NAMES ${STM32_TARGET_TRIPLET}-gcc PATHS ${TOOLCHAIN_BIN_PATH} NO_DEFAULT_PATH)
find_program(CMAKE_CXX_COMPILER NAMES ${STM32_TARGET_TRIPLET}-g++ PATHS ${TOOLCHAIN_BIN_PATH} NO_DEFAULT_PATH)
find_program(CMAKE_ASM_COMPILER NAMES ${STM32_TARGET_TRIPLET}-gcc PATHS ${TOOLCHAIN_BIN_PATH} NO_DEFAULT_PATH)

in order do not search in default path (usr).

Sources to reproduce

Steps to reproduce

Expected behavior

Screenshots

Environment (please complete the following information):

• OS: kubuntu 20.004
• Compiler: -
• stm32-cmake: e9c22b9
• cmake: 3.21
• HAL/cube/CMSIS: -

Additional context

[atsju]

Thank you for reporting the issue.
This might be a side effect of #233
Unfortunately I'm not 100% understanding the effect of NO_DEFAULT_PATH.
If you understood the root cause, could you please elaborate a bit more ?

[zisi]

As i understand by using NO_DEFAULT_PATH the searching path is restricted to ${TOOLCHAIN_BIN_PATH}.

Reference: https://cmake.org/cmake/help/latest/command/find_program.html

[atsju]

As i understand by using NO_DEFAULT_PATH the searching path is restricted to ${TOOLCHAIN_BIN_PATH}.

What exactly is the problem with this for you ? In the order of evaluation, HINTS is in position 4. What makes you find a wrong gcc (if this is your issue) ?
I mean if we use NO_DEFAULT_PATH then other users may complain because they want to pass the toolchain path by other means than hints.

[zisi]

When i use the cmake module without NO_DEFAULT_PATH and by defining the set(STM32_TOOLCHAIN_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tools/gcc-arm-none-eabi-latest") the cmake module search in /usr path and get the system compiler and not that form STM32_TOOLCHAIN_PATH.

[atsju]

Why not remove the arm-none-eabi-gcc installation from your path ? If it is installed I suppose rule 3 will take precedence and find_program will take usr path before HINT.

• If you need it in your path then it's because you are using in for an other use and then you can understand that cmake wants to use path variable like this other program
• If you don't need it in your path then remove it and problem solved

This answer is voluntarily quite abrupt but I need to understand your use case as everybody has not the same use case. I don't want to be rude :)

[robamu]

I read through this quickly but maybe I can add something to the discussion as well. I added this feature so the build system can find the toolchain binaries in the system path, which is really convenient for setting up an environment only once. Hardcoding the toolchain path in the CMakeList.txt of course works (well, right now worked) for personal projects, but if the projects are used by more people, different developers might decide to install (different) toolchains at different locations, so I prefer the approach of setting this path outside of the CMakeLists.txt file.

If this is a needed feature, an option would be to provide the CMake option STM32_TOOLCHAIN_NO_DEFAULT_PATH
and then supply NO_DEFAULT_PATH to the find_program accordingly. This would fix the issue that the user has to edit the stm32-cmake files because this option can then be set from an upper CMakeLists.txt.

I would set the default option to OFF because I would guess that most users add the path to the binaries to the path temporarily or permanently for convenience reasons. What do you think?

[robamu]

I added this is #265 . @zisi could you check whether this works for you by setting STM32_TOOLCHAIN_NO_DEFAULT_PATH to ON from you CMakeLists.txt?

[atsju]

@zisi Please try set(STM32_TOOLCHAIN_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tools/gcc-arm-none-eabi-latest" CACHE).

Notice the CACHE.

As you are the only one to reproduce the issue we will need your support before doing any changes.

[zisi]

Hey! I got

CMake Error at CMakeLists.txt:7 (set):
  set given invalid arguments for CACHE mode.

[atsju]

set(STM32_TOOLCHAIN_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tools/gcc-arm-none-eabi-latest" CACHE PATH)

[zisi]

The same error.

[atsju]

Sorry. This one should work :
set(STM32_TOOLCHAIN_PATH "${CMAKE_CURRENT_SOURCE_DIR}/tools/gcc-arm-none-eabi-latest" CACHE PATH "description")

Please let me know for a better understandig of the problem even if HINTS seems to be the correct solution

[zisi]

Neither now it works. The problem is, when a system has 2 toolchains, a project one in STM32_TOOLCHAIN_PATH and the system one in /usr/bin, by setting inside the project the STM32_TOOLCHAIN_PATH it always the project uses the /usr/bin the system one instead of the STM32_TOOLCHAIN_PATH. But if i remove the system toolchain the project uses the correct one that is setting in STM32_TOOLCHAIN_PATH .

[atsju]

Strange. Reading https://cmake.org/cmake/help/latest/command/find_program.html In your case I think it's rule 5 that finds the program.
Without CACHE, rule 6 is used but with CACHE I expected rule 2.
Thank you for feedback