The C FE (unlike C++) generates extra DW_TAG_variable in the debug info for
e.g.
extern int v;
__typeof (v) v;
or
extern int v;
__typeof (v) w;
int v = 456;
or
extern int v;
int foo (void) { return v; }
int v;
The first one gives with -g -dA:
.uleb128 0x2 # (DIE (0x2d) DW_TAG_variable)
.ascii "v\0" # DW_AT_name
.byte 0x1 # DW_AT_decl_file (u.c)
.byte 0x1 # DW_AT_decl_line
.long 0x38 # DW_AT_type
.byte 0x1 # DW_AT_external
.byte 0x1 # DW_AT_declaration
.uleb128 0x3 # (DIE (0x38) DW_TAG_base_type)
.byte 0x4 # DW_AT_byte_size
.byte 0x5 # DW_AT_encoding
.ascii "int\0" # DW_AT_name
.uleb128 0x4 # (DIE (0x3f) DW_TAG_variable)
.ascii "v\0" # DW_AT_name
.byte 0x1 # DW_AT_decl_file (u.c)
.byte 0x2 # DW_AT_decl_line
.long 0x38 # DW_AT_type
.byte 0x1 # DW_AT_external
.byte 0x9 # DW_AT_location
.byte 0x3 # DW_OP_addr
.quad v
The first decl is olddecl from merge_decls, while the second one is newdecl
from it (from the last one of them).
--
Summary: Useless DW_TAG_variable generated
Product: gcc
Version: 4.6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: jakub at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45020
