avr-gcc, .debug_frame and bitfields

[Torleif Sandnes <tsandnes at atmel dot no>]

I have configured avr-gcc like this:

bash-2.05$ avr-gcc -v
Reading specs from /usr/local/bin/../lib/gcc/avr/3.4.0/specs
Configured with: ./configure --prefix=/usr/local/ --enable-languages=c,c++ 
--enable-version-specific-runtime-libs --target=avr --with-dwarf2
Thread model: single
gcc version 3.4.0

When building objects, I am unable to make gcc output the .debug_frame section.
This is how I build my objects:

>avr-gcc -mmcu=atmega169 -gdwarf-2 -o test.elf test.c

Why does not gcc produce an .debug_frame section for the avr target?

Also, It seems to have a problem with bitfield debug information:

DW_AT_member_location seems to consequently equal -1 (ff ff ff ff) for the first 
member of a bitfield.

This bitfield:

typedef struct
{
  int   j:5;
  int   k:6;
  int   m:5;
  int   n:8;
} bitfield2_t;

result in the following debug information :

<1><20f>: Abbrev Number: 4 (DW_TAG_structure_type)
     DW_AT_sibling     : <258>	
     DW_AT_byte_size   : 3	
     DW_AT_decl_file   : 3	
     DW_AT_decl_line   : 52	
 <2><217>: Abbrev Number: 9 (DW_TAG_member)
     DW_AT_name        : j	
     DW_AT_decl_file   : 3	
     DW_AT_decl_line   : 48	
     DW_AT_type        : <67>	
     DW_AT_byte_size   : 2	
     DW_AT_bit_size    : 5	
     DW_AT_bit_offset  : 3	
     DW_AT_data_member_location: 6 byte block: 23 ff ff ff ff f 
(DW_OP_plus_uconst: 4294967295)
 <2><22a>: Abbrev Number: 9 (DW_TAG_member)
     DW_AT_name        : k	
     DW_AT_decl_file   : 3	
     DW_AT_decl_line   : 49	
     DW_AT_type        : <67>	
     DW_AT_byte_size   : 2	
     DW_AT_bit_size    : 6	
     DW_AT_bit_offset  : 5	
     DW_AT_data_member_location: 2 byte block: 23 0 	(DW_OP_plus_uconst: 0)
 <2><239>: Abbrev Number: 9 (DW_TAG_member)
     DW_AT_name        : m	
     DW_AT_decl_file   : 3	
     DW_AT_decl_line   : 50	
     DW_AT_type        : <67>	
     DW_AT_byte_size   : 2	
     DW_AT_bit_size    : 5	
     DW_AT_bit_offset  : 0	
     DW_AT_data_member_location: 2 byte block: 23 0 	(DW_OP_plus_uconst: 0)
 <2><248>: Abbrev Number: 9 (DW_TAG_member)
     DW_AT_name        : n	
     DW_AT_decl_file   : 3	
     DW_AT_decl_line   : 51	
     DW_AT_type        : <67>	
     DW_AT_byte_size   : 2	
     DW_AT_bit_size    : 8	
     DW_AT_bit_offset  : 0	
     DW_AT_data_member_location: 2 byte block: 23 1 	(DW_OP_plus_uconst: 1)

Are these problems specific for the AVR target?
How would I go about to fix these problems?

Regards,
Torleif Sandnes