[Bug target/17993] Error in dwarf2 debug output of bitfield members

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[eweddington at cso dot atmel dot com]

------- Comment #2 from eweddington at cso dot atmel dot com  2007-03-10 19:40 -------
>From the link in comment #1, on the gcc list, from Jim Wilson:


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


FYI You can get descriptive assembly by using the -dA option. This adds
comments that make the dwarf2 debug info readable. Gcc calls this
DW_AT_data_member_location.

The DWARF2 info comes from dwarf2out.c. Grepping for DW_AT_data_member_location
shows that it comes from the function add_data_member_location_attribute. The
offset comes from the function field_byte_offset. Looking at this code, it
seems to have a general problem on targets where TYPE_ALIGN of int is smaller
than TYPE_SIZE of int. This is true on avr where the size is 2 but the
alignment is 1. The code computes the end of the bitfield, subtracts the type
size, and then rounds up to the alignment, which gives -1 for the offset, which
is not a useful number. I would think the code would work better if we started
with the beginning of the bitfield, and then rounded down to the alignment. I'd
suggest checking the history of the code to see if there is a reason why it was
written this way. There may be an obscure reason why the code is like it is."

The issue is in field_byte_offset() in dwarf2out.c.

Can someone with Bugzilla permissions please mark this bug as NEW (confirmed)?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[eweddington at cso dot atmel dot com]

-- 

eweddington at cso dot atmel dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
 GCC target triplet|AVR                         |avr-*-*
   Last reconfirmed|0000-00-00 00:00:00         |2007-04-28 17:26:32
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[eweddington at cso dot atmel dot com]

------- Comment #3 from eweddington at cso dot atmel dot com  2007-08-22 17:48 -------
Bug fixed in 4.3.0 20070817 snapshot.


-- 

eweddington at cso dot atmel dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2008-03-14 16:37 -------
Fixed then.


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rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[giovannibajo at libero dot it]

-- 
Bug 17993 depends on bug 19885, which changed state.

Bug 19885 Summary: [4.0/4.1 Regression] avr dwarf-2 support is broken for head 4.0/4.1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19885

           What    |Old Value                   |New Value
----------------------------------------------------------------------------
             Status|NEW                         |WAITING
             Status|WAITING                     |RESOLVED
         Resolution|                            |FIXED

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[ericw at evcohs dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |19885


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[ericw at evcohs dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bjoern dot m dot haase at
                   |                            |web dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[berndtrog at yahoo dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |berndtrog at yahoo dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[ericw at evcohs dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ericw at evcohs dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993

[Bug target/17993] Error in dwarf2 debug output of bitfield members

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|debug                       |target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17993