[Tools] Add environmental variables support for toolchain paths

[screamerbg]

This PR adds the ability to set/override ARM_PATH, GCC_ARM_PATH, IAR_PATH and GCC_CR_PATH build system variables through environmental variables. If the env variable points to invalid path then it's ignored.

For backwards compatibility mbed_settings.py is still respected, but environmental variables have higher prio.

Note that the latest mbed CLI supports global config setting for these variables.

Also updated license of settings.py and default_settings.py and added comments

[screamerbg]

@mbed-bot: TEST

HOST_OSES=ALL
BUILD_TOOLCHAINS=ARMCC,GCC_ARM,IAR
TARGETS=K64F,NUCLEO_F411RE

[theotherjimmy]

👍 I need this. armcc on linux was broken by default for way too long.

[sg-]

one day i'll convince you to set this path for Keil MDK rather than just the compiler... one day...

[sg-]

LGTM 👍

[bridadan]

Awesome!

The CI won't test the ability to set environment variables, but it should test the ability of the tools to still respect the mbed_settings.py file. I'd like to run a few tests locally.

[bridadan]

Perhaps we should prefix the _ENV_PATHS with MBED_, so:

_ENV_PATHS = ['MBED_ARM_PATH', 'MBED_GCC_ARM_PATH', 'MBED_GCC_CR_PATH', 'MBED_IAR_PATH']

The reason is these variables are just general enough where they might conflict with some other environment variables on other people's machines.

[screamerbg]

Googled ARM_PATH and GCC_ARM_PATH env variable. Not a single result. Don't think these are general.

[theotherjimmy]

True, but if someone were to make a tool that used them, we would get unexpected behavior. I don't think anyone will klober our MBED_ prefixed environment variables.

[mbed-bot]

[Build 523]
FAILURE: Something went wrong when building and testing.

[bridadan]

CI was goofed up, this will need to be re ran.

[screamerbg]

@mbed-bot: TEST

HOST_OSES=windows
BUILD_TOOLCHAINS=GCC_ARM,IAR,ARM,uARM
TARGETS=K64F,NUCLEO_F411RE,LPC1768

[mbed-bot]

[Build ${MBED_BUILD_ID}]
FAILURE: Something went wrong when building and testing.

[screamerbg]

@mbed-bot: TEST

HOST_OSES=windows
BUILD_TOOLCHAINS=GCC_ARM,IAR,ARM,uARM
TARGETS=K64F,NUCLEO_F411RE,LPC1768

[bridadan]

I tried setting an environment variable to override the settings, but it doesn't look like it's taking priority? Did I mess up setting the environment variable?

C:\mbed>set IAR_PATH="C:/Program Files (x86)/IAR Systems/Embedded Workbench 7.2/arm"

C:\mbed>echo %IAR_PATH%
"C:/Program Files (x86)/IAR Systems/Embedded Workbench 7.2/arm"

C:\mbed>python tools\singletest.py --auto --tc IAR -V --clean
WARNING: IAR_PATH set as environment variable but doesn't exist
MBEDLS: Detecting connected mbed-enabled devices...
MBEDLS: Detected K64F[9900], port: COM238, mounted: F:
Building library CMSIS (K64F, IAR)
Copy: arm_common_tables.h
Copy: arm_const_structs.h
Copy: arm_math.h
Copy: core_ca9.h
Copy: core_caFunc.h
Copy: core_caInstr.h
Copy: core_ca_mmu.h
Copy: core_cm0.h
Copy: core_cm0plus.h
Copy: core_cm3.h
Copy: core_cm4.h
Copy: core_cm4_simd.h
Copy: core_cm7.h
Copy: core_cmFunc.h
Copy: core_cmInstr.h
Copy: core_cmSecureAccess.h
Copy: core_cmSimd.h
Copy: core_sc000.h
Copy: core_sc300.h
Copy: cmsis.h
Copy: cmsis_nvic.h
Copy: fsl_device_registers.h
Copy: MK64F12.h
Copy: MK64F12_features.h
Copy: system_MK64F12.h
Copy: MK64FN1M0xxx12.icf
ERROR: run_cmd: Command 'C:/Program Files (x86)/IAR Systems/Embedded Workbench 7.3/arm\bin\iasmarm' can't be found

[screamerbg]

Can you try setting the variable without quotes?

[screamerbg]

First setting this up incorrectly

> set IAR_PATH=C:\Program Files\IAR Workbench 7.0\arm-wrong-path

>mbed compile -t IAR -m K64F
[mbed WARNING] Could not find mbed program in current path "D:\Work\sdk\mbed-sdk-fork".
[mbed WARNING] You can fix this by calling "mbed new ." or "mbed config root ." in the root of your program.
---
WARNING: IAR_PATH set as environment variable but doesn't exist
Building project mbed-sdk-fork (K64F, IAR)
WARNING: IAR_PATH set as environment variable but doesn't exist
WARNING: IAR_PATH set as environment variable but doesn't exist
WARNING: IAR_PATH set as environment variable but doesn't exist
WARNING: IAR_PATH set as environment variable but doesn't exist
WARNING: IAR_PATH set as environment variable but doesn't exist
....

Now correctly

>set IAR_PATH=C:\Program Files\IAR Workbench 7.0\arm

>mbed compile -t IAR -c
[mbed WARNING] Could not find mbed program in current path "D:\Work\sdk\mbed-sdk-fork".
[mbed WARNING] You can fix this by calling "mbed new ." or "mbed config root ." in the root of your program.
---
Building project mbed-sdk-fork (K64F, IAR)
Compile: CAN.cpp
Compile: CallChain.cpp
Compile: AnalogIn.cpp
Compile: BusIn.cpp
Compile: BusOut.cpp
Compile: BusInOut.cpp
Compile: Ethernet.cpp
Compile: FileLike.cpp
Compile: FilePath.cpp
Compile: FileBase.cpp
Compile: FileSystemLike.cpp
Compile: I2C.cpp
Compile: I2CSlave.cpp
...

Are you sure that you're using my branch?

[bridadan]

Setting the environment variable without quotes fixed it!

[mbed-bot]

[Build 530]
FAILURE: Something went wrong when building and testing.

[screamerbg]

@mbed-bot: TEST

HOST_OSES=windows
BUILD_TOOLCHAINS=GCC_ARM,IAR,ARM
TARGETS=K64F

[screamerbg]

What's up with the CI?

[mbed-bot]

[Build ${MBED_BUILD_ID}]
FAILURE: Something went wrong when building and testing.

[sg-]

@mbed-bot: TEST

HOST_OSES=windows
BUILD_TOOLCHAINS=GCC_ARM,IAR,ARM,uARM
TARGETS=K64F,NUCLEO_F411RE,LPC1768

[mbed-bot]

[Build 533]
SUCCESS: Building succeeded and tests were run! Be sure to check the test results

[sg-]

Follow up patch to add MBED_

[SeppoTakalo]

Just why?
Why did you do this? On any given operating system there is already PATH variable used to find executables.
Why do it differently?
And do not always assume Windows operating system.

[bridadan]

@SeppoTakalo Discovering compiler executables in the PATH is a slightly different issue that needs to be addressed. I started doing that here (though the PR is not ready yet): #2057. The reason why that is non-trivial is because the build system needs to be able to find the include directories for the toolchains, so it needs to find the directories where the executables are located.

This provides a method to override both the settings file and (eventually) the toolchains found in your PATH. This is especially useful if you have multiple versions of a compiler and both can't live in your PATH.

[SeppoTakalo]

@bridadan Why do you need to know the includepaths of standard libraries? Compiler should know.

I don't think that I have ever needed to tell compiler where to find <stdio.h> for example.

[bridadan]

@SeppoTakalo I'm not familiar with the requirements here (this has been the mbedmicro/mbed code base since before I started), so it may be possible that this could be refactored. For the case of the ARM toolchain, here is one instance where the include path is used: https://github.com/mbedmicro/mbed/blob/master/tools/toolchains/arm.py#L38.

It's linking to libs as well. Here are the lines I found after a quick search:

• https://github.com/mbedmicro/mbed/blob/master/tools/toolchains/arm.py#L261
• https://github.com/mbedmicro/mbed/blob/master/tools/toolchains/arm.py#L264
• https://github.com/mbedmicro/mbed/blob/master/tools/toolchains/arm.py#L267