mbed_blinky build broken in some BLE targets

[toyowata]

Description

• Type: Bug
• Priority: Major

---

Bug

Target
nRF51-DK, nRF51-Dongle and TY51822R3

Toolchain:
ARM (online IDE)

Toolchain version:
5.06

Expected behavior
mbed_blinky example build successful

Actual behavior
mbed_blinky example can not build (compile error)

Steps to reproduce

• Import mbed_blinky example:
  https://developer.mbed.org/teams/mbed/code/mbed_blinky/

• Set target to nRF51-DK

• Update mbed library to 145

• Build example and I got error below:

Error: Symbol SysTick_Handler multiply defined (by us_ticker.o and startup_nRF51822.o).

I could not see any problem in mbed library rev 144 or older.

[0xc0170]

cc @pan- @nvlsianpu

[pan-]

It works well if compiled locally from the sources but doesn't in the online IDE.
I suspect that it is related to how ARM compiler handle weak symbols when they are in a library.

[0xc0170]

we shall not use weak IRQ handlers within HAL, we got NVIC set/get vectors so use that.

[pan-]

@bulislaw @nvlsianpu Any reason to keep the weak definition of Systick_Handler in us_ticker.c (see) ?

It is only used if the RTOS is present (see) and in that case it is imported from rtx_os.h.

[nvlsianpu]

@pan- No reason to have these weka symbol. Can you remove it? I haven't time for mbed until next week.

[pan-]

@nvlsianpu Thank you, I'm waiting for @bulislaw answer before submitting the fix, he introduce the change, maybe there is a deeper reason behind the inclusion of this weak symbol.

[bulislaw]

@pan- I don't think there is one really. I've just translated old symbol name to a new one, it used to be MBED_WEAK void OS_Tick_Handler() { }.

[toyowata]

Confirmed the fix in mbed library rev 147. Thanks.