CMake exported build fails with multiple --source arguments

Note: This is just a template, so feel free to use/remove the unnecessary things

Description

• Type: Bug
• Related issue: Correct mbed export with multiple --source params #6143 and mbed export fails with switch "--source .." mbed-cli#590
• Priority: Blocker

---

Bug

Target
All targets (e.g. TARGET_NUCLEO_F103RB)

Toolchain:
GCC_ARM

Toolchain version:
7.2.1

mbed-cli version:
1.5.0

mbed-os sha:
192a8e5

---

Folder structure I use for my project:

├── project.cmake
├── src
│   └── main.cpp
└── submodules
    ├── mbed-memory-status
    └── mbed-os

Expected behavior

mbed config MBED_OS_DIR submodules/mbed-os
mbed export -i make_gcc_arm -m NUCLEO_F103RB --source src --source submodules --build .
make -j

This generates the file src.elf since it automatically names the project what I give as the first --source. This builds successfully.

Actual behavior

mbed config MBED_OS_DIR submodules/mbed-os
mbed export -i cmake_gcc_arm -m NUCLEO_F103RB --source src --source submodules --build .
cmake .
make all

...

[100%] Linking CXX executable src
/usr/local/Cellar/gcc-arm-none-eabi-74/20171218/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld: cannot open output file src: Is a directory
collect2: error: ld returned 1 exit status

Tries to generate the file src which results in an error in the linker since it has the same name as my src folder with no extension. In my opinion this file should get the elf extension, which would resolve the problem. I also expect to be able to specify the project name to the export command, which at the moment is not possible according to the mbed-cli arguments to the export tool.

Steps to reproduce

---

Enhancement

The workaround I found to do mostly what I want is to add a line in project.cmake that changes the OUTPUT_NAME of the target property to the name specified as the first --source argument.

set_target_properties(src PROPERTIES OUTPUT_NAME "mbed-os-example")

but as said, that is merely a workaround

Reason to enhance or problem with existing solution
Build (linker) files on CMake export with multiple --source arguments

Suggested enhancement
I suggest adding a argument to the mbed-cli (and other parts of the export) to specify the project name e.g. -p mbed-os-example or --project mbed-os-example that adds a line to the CMakeLists.txt to specify the output name. Ideally the output extension for the CMake export should be changed to elf like the make_gcc_arm export does.

[0xc0170]

@theotherjimmy Please review
[Mirrored to Jira]

[theotherjimmy]

@vidavidorra the project name may be set the mbed_app.json section artifact_name (docs see the "mbed_app.json Specification" section). If it's not set, it defaults to the name of the directory of the first --source argument, which was probably your src dir. I agree that the cmake exporter should probably append a .elf.
[Mirrored to Jira]

[adbridge]

Internal Jira reference: https://jira.arm.com/browse/IOTCORE-324

@theotherjimmy I've updated to mbed-os-5.10.0 and tested this again, especially specifying the name using the artifact_name you mentioned. I've also tested artifact-name but with same outcome.

{
  "config": {
    "artifact_name" : "example",
...

I'm using that with cmake exporter

mbed export -i cmake_gcc_arm --app-config mbed_app.json --source ./source

but when I look in the generated CMakeLists.txt I see that source is still used as name. I.e. PROJECT(source C CXX ASM) is in there where I'd now expect example instead of source. This is not only for project name but also for SET_TARGET_PROPERTIES, add_custom_command(TARGET etc.

@theotherjimmy I've also just tested the CMake export on mbed-os-5.10.0 and don't think #8251 is necessary anymore. Not sure why though, but the linker no longer gives the error.

Also I'm wondering what the project name is for other exports (GCC_ARM, Make). If those end with .elf I think #8251 still makes sense, but if they don't IMHO #8251 is not necessary.
If the latter is the case IMHO the elf extension can simply be added to the output file using the following rather than renaming the project. That is, if there is not a more elegant way to do so and this doesn't break anything else.

add_custom_command(TARGET source POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E rename $<TARGET_FILE:source> $<TARGET_FILE:source>.elf
    )