new-abi crash with virtual derivation
scott snyder
snyder@fnal.gov
Tue Nov 21 12:41:00 GMT 2000
hi -
g++ from today's cvs (20001121) segfaults on the following input
with -fnew-abi (on a linux/i86 box):
-----------------------------------------------------------
class d0_Object
{
public:
virtual ~d0_Object ();
};
class M10 : virtual public d0_Object {};
class M4 : virtual public M10 {};
class M9
: public M4, virtual public M10
{
public:
M9 ();
};
M9::M9 () {}
-----------------------------------------------------------
$ ./cc1plus -fnew-abi -lang-c++ y.cc
M9::M9() d0_Object::d0_Object() d0_Object::__base_ctor() d0_Object::__comp_ctor() M10::M10() M10::__base_ctor(const void**) M10::__comp_ctor() M10::~M10() M10::~__base_dtor(const void**) M10::~__comp_dtor() M10::~__deleting_dtor() M4::M4() M4::__base_ctor(const void**) M4::__comp_ctor() M4::~M4() M4::~__base_dtor(const void**) M4::~__comp_dtor() M4::~__deleting_dtor() M9::__base_ctor(const void**) M9::__base_ctor(const void**) M9::__comp_ctor() M9::__comp_ctor() void M10::_ZTv0_n12_N3M10D1Ev() void M10::_ZTv0_n16_N3M10D0Ev() void M4::_ZTv0_n12_N2M4D1Ev() void M4::_ZTv0_n16_N2M4D0Ev() void M9::_ZTv0_n12_N2M9D1Ev() void M9::_ZTv0_n16_N2M9D0Ev() M9::~M9() M9::~__base_dtor(const void**) M9::~__comp_dtor() M9::~__comp_dtor()
y.cc:19: Internal error: Segmentation fault.
Please submit a full bug report.
See <URL: http://www.gnu.org/software/gcc/bugs.html > for instructions.
Here's where it's crashing:
Program received signal SIGSEGV, Segmentation fault.
0x8234ef5 in expand_expr (exp=0x401a7fe0, target=0x0, tmode=VOIDmode,
modifier=EXPAND_NORMAL) at ../../egcs/gcc/expr.c:7300
7300 else if (TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST
and the tree here is:
(gdb) call debug_tree (exp)
<plus_expr 0x401a7fe0
type <pointer_type 0x40175600
type <array_type 0x4016f980 type <pointer_type 0x40150280>
BLK
size <integer_cst 0x4016a4a0 constant 288>
unit size <integer_cst 0x4016a4c0 constant 36>
align 32 symtab 0 alias set -1 domain <integer_type 0x40169a80>
pointer_to_this <pointer_type 0x40175600>>
unsigned SI
size <integer_cst 0x40145f80 constant 32>
unit size <integer_cst 0x40145fa0 constant 4>
align 32 symtab 0 alias set -1>
arg 0 <cond_expr 0x401a8000 type <pointer_type 0x40175600>
arg 0 <integer_cst 0x4014cf20 constant 0>
arg 1 <integer_cst 0x4014c140 constant 0>
arg 2 <addr_expr 0x401a8020 type <pointer_type 0x40175600>
readonly constant arg 0 <var_decl 0x4016fa00 _ZTT2M9>>>>
I.e., a plus_expr with only one argument?
I think i found where this tree is being built, in build_new_method_call():
sub_vtt = build (PLUS_EXPR, TREE_TYPE (vtt), vtt,
BINFO_SUBVTT_INDEX (basetype_path));
sub_vtt = build_indirect_ref (sub_vtt, NULL);
At this point, i have:
(gdb) call debug_tree (vtt)
<cond_expr 0x401a5660
type <pointer_type 0x40175600
type <array_type 0x4016f980 type <pointer_type 0x40150280>
BLK
size <integer_cst 0x4016a4a0 constant 288>
unit size <integer_cst 0x4016a4c0 constant 36>
align 32 symtab 0 alias set -1 domain <integer_type 0x40169a80>
pointer_to_this <pointer_type 0x40175600>>
unsigned SI
size <integer_cst 0x40145f80 constant 32>
unit size <integer_cst 0x40145fa0 constant 4>
align 32 symtab 0 alias set -1>
arg 0 <parm_decl 0x4016c880
type <boolean_type 0x4014e880 bool unsigned type_6 QI
size <integer_cst 0x40145400 constant 8>
unit size <integer_cst 0x40145f00 constant 1>
align 8 symtab 0 alias set -1 precision 1
min <integer_cst 0x4014cea0 constant 0>
max <integer_cst 0x4014cee0 constant 1>>
unsigned QI file y.cc line 16 size <integer_cst 0x40145400 8> unit size <integer_cst 0x40145f00 1>
align 8 context <function_decl 0x4016c600 M9> initial <boolean_type 0x4014e880 bool>>
arg 1 <parm_decl 0x4016c800 __vtt_parm
type <pointer_type 0x40150300 type <pointer_type 0x40150280>
unsigned SI size <integer_cst 0x40145f80 32> unit size <integer_cst 0x40145fa0 4>
align 32 symtab 0 alias set -1>
unsigned SI file y.cc line 16 size <integer_cst 0x40145f80 32> unit size <integer_cst 0x40145fa0 4>
align 32 context <function_decl 0x4016c600 M9> initial <pointer_type 0x40150300> chain <parm_decl 0x4016c880>>
arg 2 <addr_expr 0x401a5640 type <pointer_type 0x40175600>
readonly constant
arg 0 <var_decl 0x4016fa00 _ZTT2M9 type <array_type 0x4016f980>
readonly addressable asm_written used public static common virtual BLK file y.cc line 16 size <integer_cst 0x4016a4a0 288> unit size <integer_cst 0x4016a4c0 36>
align 256 context <record_type 0x40169e80 M9> initial <constructor 0x40173a00>
(mem/s/u:BLK (symbol_ref:SI ("_ZTT2M9")) 0) chain <var_decl 0x4016f780 _ZTC2M90_3M10>>>>
and
(gdb) call debug_tree (basetype_path)
<tree_vec 0x40167980
type <record_type 0x40160b00 M10 addressable tree_1 tree_2 tree_3 needs-constructing type_1 type_2 type_4 type_5 BLK
size <integer_cst 0x40145f80 constant 32>
unit size <integer_cst 0x40161b20 constant 4>
align 32 symtab 0 alias set -1
fields <type_decl 0x40160c80 M10 type <record_type 0x40160b00 M10>
nonlocal VOID file y.cc line 8
align 1 context <record_type 0x40160b00 M10>
>
needs-constructor needs-destructor ~X() X() X(constX&) this=(X&) n_parents 1 use_template=0 interface-unknown vtable-needs-writing
member-functions <tree_vec 0x4015f8c0
elt 0 <overload 0x4015d7d0>
elt 1 <function_decl 0x40160e00 M10>
elt 2 <function_decl 0x40162d00 operator=>
elt 3 <overload 0x4015d850>
elt 4 <overload 0x4015d820>
elt 5 <function_decl 0x40163a00 __comp_dtor>
elt 6 <function_decl 0x40163c00 __base_dtor>
elt 7 <function_decl 0x40163800 __deleting_dtor>>
pointer_to_this <pointer_type 0x40160b80> reference_to_this <reference_type 0x40162b00> chain <type_decl 0x40160c00 M10>>
public static
elt 0 <tree_vec 0x40167840>
elt 1 <integer_cst 0x4016d7a0 0>
elt 2 <plus_expr 0x40165560>
elt 3 <tree_list 0x40161bc0>
thanks,
sss
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