Testing GDC (GCC 7.1) on Runtime-less ARM Cortex-M

[Iain Buclaw via D.gnu]

On 17 July 2017 at 22:26, Mike via D.gnu <d.gnu at puremagic.com> wrote:
> On Wednesday, 28 June 2017 at 22:17:09 UTC, Iain Buclaw wrote:
>
>> A thought just occurred to me, you are compiling the entire program +
>> object.d right?  Nothing else will link/be linked to the binary?
>>
>> If that is the case, you should definitely compile with -fwhole-program.
>> I suspect that may cut down your compilation time by half or even more.
>
>
> I'm back and have spend the last two days trying to get my project compiled
> with -fwhole-program in an effort to reduce the compile times, but I haven't
> had any success.
>
> Regardless of what I do, the compiler doesn't emit anything except main.
>
> arm-none-eabi-gdc -c -O2 -finline-functions -nophoboslib -nostdinc
> -nodefaultlibs -nostdlib -fno-emit-moduleinfo -mthumb -mcpu=cortex-m4
> -fwhole-program -Isource/entrypoint -fno-bounds-check -ffunction-sections
> -fdata-sections source/gcc/attribute.d source/runtime/exception.d
> source/runtime/invariant.d source/runtime/object.d source/runtime/dmain2.d
> source/board/lcd.d source/board/ILI9341.d source/board/package.d
> source/board/statusLED.d source/board/ltdc.d source/board/random.d
> source/board/spi5.d source/stm32f42/nvic.d source/stm32f42/gpio.d
> source/stm32f42/flash.d source/stm32f42/scb.d source/stm32f42/spi.d
> source/stm32f42/pwr.d source/stm32f42/ltdc.d source/stm32f42/trace.d
> source/stm32f42/rcc.d source/stm32f42/bus.d source/stm32f42/rng.d
> source/stm32f42/dma2d.d source/stm32f42/mmio.d source/main.d -o
> binary/firmware.o
>
> arm-none-eabi-nm binary/firmware.o
>          U _Dmain
>          U _d_run_main
> 00000000 T main
>
> Are you sure this works with multiple modules passed to the compiler on one
> line?
>

Humm, it looks like it can't sufficiently determine that both the
_d_run_main declarations are for the same symbol.

After making a tweak, it compiles a program that does a little bit more.

https://gist.github.com/ibuclaw/d1fad77b074fded2682a16df93369a84

This is the compiled result:

https://gist.github.com/ibuclaw/93c707f4729ffc4376539283defdc709

Iain.