Hi,
on s390x I see broken debug info generated for the attached C++
testcase (compile with -O2 -g -fPIC).
The debug info contains a symbol reference with a @GOTENT modifier
what should not happen (and is not accepted by gas):
.LLST3:
.8byte .LVL3-.Ltext0
.8byte .LVL4-.Ltext0
.2byte 0xa
.byte 0x9e
.uleb128 0x8
.8byte _ztist12future_er...@gotent
.8byte 0x0
.8byte 0x0
The problem is that the sched2 pass breaks the variable location
information by moving an insn setting r1 over a var_location debug
insn describing a variable location as being r1.
in 202.split4:
29: var_location r10
33: var_location r13 + 8
34: var_location r10
30: r1 = &(A got entry)
31: r1 = [r1]
83: [r13] = r2
32: r1 = [r1]
35: var_location A => r1 <-- problematic location information
36: [r13 + 8] = r10
37: [r13 + 16] = r1
79: r1 = &(B got entry)
41: r3 = [r1]
in 203.sched2:
...
32: r1 = [r1]
37: [r13 + 16] = r1
79: r1 = &(B got entry) <-- insn moved over 35
83: [r13] = r2
29: var_location r10
33: var_location r13 + 8
34: var_location r10
35: var_location r1 !!! the variable location gets corrupted
since insn 79 has been moved over it
36: [r13 + 8] = r10
41: r3 = [r1]
The variable locations are intended to stay right after the insn which
does the relevant assignment by generating an ANTI dep between them
but we also create deps between unrelated insns:
sched-deps.c:2790
if (prev && NONDEBUG_INSN_P (prev))
add_dependence (insn, prev, REG_DEP_ANTI);
This code creates a dependency between 83 and 29 (although the
assignment is unrelated). This together with the fact that all debug
insns are always been kept from being moved over each other makes all
the debug insns to get stuck after insn 83. Although in order to keep
the information correct insn 35 has to stay after 32.
Bye,
-Andreas-
class exception
{
virtual const char *what () const throw ();
};
namespace std
{
template < typename _Alloc > class allocator;
template < class _CharT > struct char_traits;
template < typename _CharT, typename _Traits =
char_traits < _CharT >, typename _Alloc =
allocator < _CharT > >class basic_string;
typedef basic_string < char >string;
template < typename _Tp > class allocator
{
};
template < typename _CharT, typename _Traits,
typename _Alloc > class basic_string
{
public:basic_string ();
basic_string (const _CharT * __s, const _Alloc & __a = _Alloc ());
};
class logic_error:public exception
{
public:logic_error (const string & __arg);
};
class error_category
{
};
struct error_code
{
error_code (int __v, const error_category & __cat):_M_value (__v),
_M_cat (&__cat)
{
}
private:int _M_value;
const error_category *_M_cat;
};
enum future_errc
{
};
extern const error_category *const future_category;
inline error_code make_error_code (future_errc __errc)
{
return error_code (static_cast < int >(__errc), *future_category);
}
class future_error:public logic_error
{
error_code _M_code;
public: future_error (future_errc __ec):logic_error ("std::future_error"),
_M_code (make_error_code (__ec))
{
}
};
void __throw_future_error (int __i)
{
throw future_error (future_errc (__i));
}
}
