How to build a bare metal program with meson

[Wink Saville]

I've created a trivial bare metal application that prints "Hi\n" using a Makefile, but would like to use Meson.

My feeble first attempt fails and I'm hoping someone could give me some additional guidance:

wink@wink-envy build]$ meson .. --cross-file ../arm-eabi-cross_file.txt --buildtype plain

The Meson build system

Version: 0.27.0-research

Source dir: /home/wink/prgs/libs/baremetal-hi

Build dir: /home/wink/prgs/libs/baremetal-hi/build

Build type: cross build

Host machine cpu: arm

Target machine cpu: arm

Build machine cpu: x86_64

Project name: Bare metal Hi

/home/wink/opt/cross/lib/gcc/arm-eabi/5.2.0/../../../../arm-eabi/bin/ld: cannot find crt0.o: No such file or directory

/home/wink/opt/cross/lib/gcc/arm-eabi/5.2.0/../../../../arm-eabi/bin/ld: cannot find -lc

collect2: error: ld returned 1 exit status

Meson encountered an error in file meson.build, line 1, column 0:

Compiler /home/wink/opt/cross/bin/arm-eabi-gcc can not compile programs.

Thanks in advance,

Wink

[Jussi Pakkanen]

On Tue, Oct 13, 2015 at 5:13 AM, Wink Saville <wi...@saville.com> wrote:

I've created a trivial bare metal application that prints "Hi\n" using a Makefile, but would like to use Meson.

My feeble first attempt fails and I'm hoping someone could give me some additional guidance:

The reason this is happening is that Meson will test all compilers by compiling a small sample program before doing anything else. In this case it fails, probably due to some missing command line arguments or other settings.

Could you compile a simple helloworld application manually and tell what command line works for you? You can find the test source Meson tries to compile in meson-private/sanitycheckc.c, so if you have it handy just use that one.

[Wink Saville]

My bare metal application is about as simple as you can get for a bare metal

application. It consists for a startup.S arm file that does nothing but setup

a stack and invoke "main(void)" in test.c.

The GNU Makefile is pretty simple:

[wink@wink-envy baremetal-hi]$ cat Makefile

# Delete implict rules

.SUFFIXES:

cross=arm-eabi-

cpu=arm926ej-s

CC=$(cross)gcc

LD=$(cross)ld

OC=$(cross)objcopy

cflags=-mcpu=$(cpu) -I. -Wall -O2 -g

.PHONY: all

all: test.bin

test.o: test.c

$(CC) $(cflags) -c -o test.o test.c

startup.o: startup.S

$(CC) $(cflags) -c -o startup.o startup.S

test.bin: test.o startup.o

$(LD) -T link.ld test.o startup.o -o test.elf

$(OC) -O binary test.elf test.bin

.PHONY: run

run: test.bin

qemu-system-arm -M versatilepb -m 128M -nographic -kernel test.bin

  

.PHONY: clean

clean:

rm -rf *.o *.elf *.bin

The sanitycheckcpp.mm file won't compile because it attempts to "#import<stdio.h>"

which doesn't exist for my bare metal application. Also it's a c++ application whereas

I'm only using "c" and my project statement only says I'm using 'c' and 'as':

project('Bare metal Hi', ['c','as'])

So it would be inappropriate to use "c++" for a sanity check and

of course only compilation can be tested as I don't think meson

can always rely on being able to run the resulting sanity check code.

So what do you suggest the next step should be?

Thanks,

Wink

[Jussi Pakkanen]

On Thu, Oct 15, 2015 at 5:31 AM, Wink Saville <wi...@saville.com> wrote:

 

The sanitycheckcpp.mm file won't compile because it attempts to "#import<stdio.h>"which doesn't exist for my bare metal application. Also it's a c++ application whereas

I'm only using "c" and my project statement only says I'm using 'c' and 'as':

You should not have sanitycheckcpp.mm file in there, that's for objective c++. I assume you ran ./run_tests.sh and just checked out what remained in the work dir.

If this is the case then do run Meson on your own project and then check out meson-private in your build dir. There should be a sanitycheckc.c in there.

 

project('Bare metal Hi', ['c','as'])

So it would be inappropriate to use "c++" for a sanity check and

of course only compilation can be tested as I don't think meson

can always rely on being able to run the resulting sanity check code.

Meson only tries to run the executable if an exe wrapper is defined. The sanity check binary also does not try to use stdio or anything like that. If you can get the C source and test what flags are needed to compile it, I can fix it.

PS Don't put "as" in the list of languages, it will fail. You can put .S files into list of sources, and GCC will do the right thing automatically AFAICR.

[Wink Saville]

My mistake I was looking for sanitycheck in the meson sources. I've created pull request #282 which resolves the sanitycheck issue for me.

[Wink Saville]

I also needed to fix cross linking and created pull request #283. With

both changes I was successfully able to use meson to create a bare metal

application.