SUMMARY:
In gcc 3.2.3 (and other versions) the DWARF information created by gcc does not
create DW_AT_location attribute for local (static) variables inside a C++
constructor.
WHAT::
The reproducer below shows TWO problems related to debug information available
regarding variables inside a C++ a constructor. One type is (1) a local
variable inside a constructor and second type is (2) a local _static_ variable
inside a constructor. Sometimes TV is able to see the case (1) but only in the
Program Browser (PB); but case (2) is never correctly shown in TV, neither when
Diving, Stack Frame or in PB.
For some versions of gcc TV can show type (1) in the PB, but for all gcc
versions TV fails to show type (2) at all.
This problem is not related to TV alone, GDB fails to see these variables as
well.
On gcc 3.2.3, TV can see type (1) only in PB, but type (2) is
not visible to TV at all (only in symtable).
With PGI-7.0.5 (and some other non-gcc compilers) TV can see everything
alright.
REPRODUCE/TEST::
See attached c++ file.
dbreak 25
drun
dprint iii
dprint foofoo
WHY::
In some gcc versions there is no DWARF information whatsoever related to types
(1) and (2).
In gcc 3.2.3 (and others, e.g. 4.0.3) the DWARF information created by gcc does
not create DW_AT_location attribute for neither type (1) and (2), e.g.
less tx_local.gcc3.2.3.txt
<2><1760>: Abbrev Number: 41 (DW_TAG_variable)
DW_AT_name : foofoo
DW_AT_decl_file : 1
DW_AT_decl_line : 28
DW_AT_type : <178a>
less tx_local.pgi7.0.5.txt
<1><1048>: Abbrev Number: 14 (DW_TAG_variable)
DW_AT_name : foofoo
DW_AT_type : <1864>
DW_AT_location : 5 byte block: 3 30 e0 4 8 (DW_OP_addr: 804e030; )
Therefore TV (or gdb) does not have enough information to resolve these
variables.
These variables do exist in the symtable, e.g.:
d1.<> sgrep foofoo
{kind loader_symbol} {id 1|795} {full_pathname
##/nfs/netapp0/user/home/seppo/tx_local.out_gcc3.2.3#tx_local_var_cpp_constructor.cxx/_ZZN1AC1Eii\
E6foofoo} {artificial 0} {scope_owner 1|220} {loader_name _ZZN1AC1EiiE6foofoo}
\
{loader_file_path tx_local_var_cpp_constructor.cxx} {location {{ldam
0x900007a0\
}}} {address_class module_static_var} {length 96} {weak 0}
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
#include <stdio.h>
class A {
public:
A (int a, int b);
int a_;
int b_;
int c_;
};
A::A (int a, int b) : a_ (a), b_ (b), c_ (0)
{
int iii;
iii = 42;
c_ = a_ * b_;
c_ += iii;
static const int foofoo[6][4] = { {0,1,2,3},
{1,2,3,4},
{2,3,4,5},
{3,4,5,6},
{4,5,6,7},
{5,6,7,8} };
printf("c_ = %d\n", c_);
printf("foofoo = %d\n", foofoo);
}
int main (int, char* *)
{
int a = 34, b = 56;
A x (a, b);
return x.a_ + x.b_;
}
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
--
Summary: Local variables in C++ constructor not visible for
debugging
Product: gcc
Version: 3.2.3
Status: UNCONFIRMED
Severity: critical
Priority: P3
Component: debug
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: seppo at totalviewtech dot com
GCC build triplet: linux-x86 (2.6.16.13-4-smp)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33044
