Build error occurs by exporting mbed classic sample to GCC (ARM Embedded) toolchain on mbed online compiler

[TomoYamanaka]

Description

• Type: Bug
• Priority: Major

---

Bug

As exporting mbed classic sample(e.g. mbed-blinky) to GCC (ARM Embedded) toolchain on mbed online compiler, the below build error will occurs.
This error occurs by using mbed classic rev.145 or later.

../mbed/TARGET_RZ_A1H/TOOLCHAIN_GCC_ARM/system_MBRZA1H.o: In function `InitMemorySubsystem':
system_MBRZA1H.c:(.text.InitMemorySubsystem+0x24): undefined reference to `__v7_all_cache'
collect2.exe: error: ld returned 1 exit status

I consider that cause of this error is the lack of __v7_all_cache in GCC only.
Before rev.144, it's function has been implemented.
But in rev.145, it seems that the substance of it's function does not exist because cache.S has been deleted, as a result, the above error occurs.

[0xc0170]

I assume its RZ_A1H target. who and when was cache.S deleted?

cc @theotherjimmy

[theotherjimmy]

I don't have the answer to that question @0xc0170

[theotherjimmy]

CMSIS 5 update? seems to affect all releases >= 5.5.0

[0xc0170]

Thanks Jimmy.

@TomoYamanaka For gcc, this function is declared as extern, where was (should be) the definition of this function?

What we are missing here as this is local issue, what is your GCC ARM version?

[toyowata]

@0xc0170
The cache.S was in here, but removed by CMSIS5 update:
https://github.com/ARMmbed/mbed-os/tree/mbed-os-5.4/cmsis/TOOLCHAIN_GCC/TARGET_CORTEX_A

[0xc0170]

Thanks @TomoYamanaka . I'll send PR shortly, adding this file back