Re: [avr-libc-dev] [Debian Wheezy] crttn13a.o: No such file?

[Georg-Johann Lay]

Joerg Wunsch schrieb:
> As Ivan Shmakov wrote:
>
> >         I've just tried to build a program for ATtiny13A on a recent
> >         Debian Wheezy, and got:
> >
> > $ avr-gcc -g -O2 -Wall -pedantic -std=gnu99 -mmcu=attiny13a \
> >       -L/usr/lib/avr/lib/avr25  ../6pp5iouyw6unnen7egfroozp8b.c \
> >       -o 6pp5iouyw6unnen7egfroozp8b 
> > /usr/lib/gcc/avr/4.7.0/../../../avr/bin/ld: crttn13a.o: No such file: No such file or directory
> > collect2: error: ld returned 1 exit status
>
> Johann, is this the symptom for bug 35407?

Yes.

The convention is that crt*.o is located in the respective multilib 
directory, which is

   $install/avr/lib/avr25/tiny-stack/

for ATtiny13A.  If there is no crttn13a.o, the linker will complain 
because the driver cooks up the options for the linker from -mmcu= and 
-msp8 and others like -nostartfiles.

Work around is

1) Supply CRT by hand: Link with

   -nostartfiles $install/avr/lib/avr25/crttn13a.o

2) Or move crttn13a.o from

   $install/avr/lib/avr25/

to

   $install/avr/lib/avr25/tiny-stack/

@Jörg:  What I don't understand is that with #35407, crt*.o for the tiny 
-stack targets occurs twice: once in tiny-stack and again one level higher.

FYI, you can query gcc's multilib layout by means of

$ avr-gcc -print-multi-lib
.;
avr25;@mmcu=avr25
avr3;@mmcu=avr3
avr31;@mmcu=avr31
avr35;@mmcu=avr35
avr4;@mmcu=avr4
avr5;@mmcu=avr5
avr51;@mmcu=avr51
avr6;@mmcu=avr6
avrxmega2;@mmcu=avrxmega2
avrxmega4;@mmcu=avrxmega4
avrxmega5;@mmcu=avrxmega5
avrxmega6;@mmcu=avrxmega6
avrxmega7;@mmcu=avrxmega7
tiny-stack;@msp8
avr25/tiny-stack;@address@hidden


For a specific device:

$ avr-gcc -print-multi-directory
.

$ avr-gcc -print-multi-directory -mmcu=attiny13a
avr25/tiny-stack

$ avr-gcc -print-multi-directory -mmcu=avr25
avr25

$ avr-gcc -print-multi-directory -mmcu=avr25 -msp8
avr25/tiny-stack

This means:

In order to query all multilibs and respective locations and build 
options, you can use -print-multi-lib.

In order to query where to put a specific crt*.o, use 
-print-multi-directory.


This is nothing new and there is no need to hard-code compiler versions 
or multilib layout in the avr-libc build system.

For example, from some 4.7.0 snapshot without xmega support and without 
PR52737, you might get:

$ avr-gcc-4.7.0 -print-multi-lib
.;
avr25;@mmcu=avr25
avr3;@mmcu=avr3
avr31;@mmcu=avr31
avr35;@mmcu=avr35
avr4;@mmcu=avr4
avr5;@mmcu=avr5
avr51;@mmcu=avr51
avr6;@mmcu=avr6
tiny-stack;@mtiny-stack
avr25/tiny-stack;@address@hidden


Johann