I installed gcc-4.5-20091224 snapshot and noticed that for simple
variable declaration
I get two DW_TAG_variable dies in the object file. For example, the
following
code
int xxxxx;
main()
{xxxxx=1;}
generates (with -g -gdwarf2 -O0 switches):
<1><54>: Abbrev Number: 4 (DW_TAG_variable)
<55> DW_AT_name : (indirect string, offset: 0x36): xxxxx
<59> DW_AT_decl_file : 1
<5a> DW_AT_decl_line : 1
<5b> DW_AT_type : <0x4d>
<5f> DW_AT_external : 1
<60> DW_AT_declaration : 1
<1><61>: Abbrev Number: 5 (DW_TAG_variable)
<62> DW_AT_name : (indirect string, offset: 0x36): xxxxx
<66> DW_AT_decl_file : 1
<67> DW_AT_decl_line : 1
<68> DW_AT_type : <0x4d>
<6c> DW_AT_external : 1
<6d> DW_AT_location : 9 byte block: 3 0 0 0 0 0 0 0 0 (DW_OP_addr: 0)
Is the above normal? 4.3.2 compiler generates only one die, the second
one with
DW_AT_location attribute, which is correct.
I also noticed that this example (were variable is not used):
int xxxxx;
main()
{}
generates only one DW_TAG_variable, the one with DW_AT_location, which
again
should be correct.
I ran into this problem by porting some GDB code that uses DWARF2 and
got surprised
to see this change from the previous version of gcc (4.3).
Thanks,
Nenad
