https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94887
Bug ID: 94887
Summary: -fdebug-types-section drops DW_TAG_formal_parameter
and DW_TAG_template_type_param
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: vries at gcc dot gnu.org
Target Milestone: ---
Consider this test-case, minimized from gdb testsuite test-case py-methods.cc:
...
$ cat py-xmethods.cc
template <typename T>
class G
{
public:
template <typename T1>
T mul(const T1 t1) { return t1 * 5; }
};
int
main(void)
{
G<int> g;
return g.mul (1.0);
}
...
Without -fdebug-types-section, we have:
...
$ g++ py-xmethods.cc -g
$ gdb -batch a.out -ex start -ex "ptype g"
Temporary breakpoint 1 at 0x4004cf: file py-xmethods.cc, line 13.
Temporary breakpoint 1, main () at py-xmethods.cc:13
13 return g.mul (1.0);
type = class G<int> [with T = int] {
public:
T mul<double>(double);
}
...
But with -fdebug-types-section, we have:
...
$ g++ py-xmethods.cc -g -fdebug-types-section
$ gdb -batch a.out -ex start -ex "ptype g"
Temporary breakpoint 1 at 0x4004cf: file py-xmethods.cc, line 13.
Temporary breakpoint 1, main () at py-xmethods.cc:13
13 return g.mul (1.0);
type = class G<int> [with T = int] {
<no data fields>
}
...
Or with the tentative gdb patch from here (
https://sourceware.org/bugzilla/show_bug.cgi?id=25898#c3 ), we have:
...
$ gdb -batch a.out -ex start -ex "ptype g"
Temporary breakpoint 1 at 0x4004cf: file py-xmethods.cc, line 13.
Temporary breakpoint 1, main () at py-xmethods.cc:13
13 return g.mul (1.0);
type = class G<int> [with T = int] {
public:
T mul<double>(void);
}
...
Note the 'void' instead of 'double'.
Without -fdebug-types-section, we have:
...
<1><f0>: Abbrev Number: 2 (DW_TAG_class_type)
<f1> DW_AT_name : (indirect string, offset: 0x225): G<int>
<f5> DW_AT_byte_size : 1
<f6> DW_AT_decl_file : 1
<f7> DW_AT_decl_line : 2
<f8> DW_AT_sibling : <0x12f>
<2><fc>: Abbrev Number: 3 (DW_TAG_subprogram)
<fd> DW_AT_external : 1
<fd> DW_AT_name : mul<double>
<101> DW_AT_decl_file : 1
<102> DW_AT_decl_line : 6
<103> DW_AT_linkage_name: _ZN1GIiE3mulIdEEiT_
<107> DW_AT_type : <0x12f>
<10b> DW_AT_accessibility: 1 (public)
<10c> DW_AT_declaration : 1
<10c> DW_AT_object_pointer: <0x11c>
<110> DW_AT_sibling : <0x127>
<3><114>: Abbrev Number: 4 (DW_TAG_template_type_param)
<115> DW_AT_name : T1
<118> DW_AT_type : <0x136>
<3><11c>: Abbrev Number: 5 (DW_TAG_formal_parameter)
<11d> DW_AT_type : <0x142>
<121> DW_AT_artificial : 1
<3><121>: Abbrev Number: 6 (DW_TAG_formal_parameter)
<122> DW_AT_type : <0x136>
<1><14d>: Abbrev Number: 11 (DW_TAG_subprogram)
<14e> DW_AT_specification: <0xfc>
<152> DW_AT_object_pointer: <0x178>
<156> DW_AT_low_pc : 0x4004ee
<15e> DW_AT_high_pc : 0x24
<166> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<168> DW_AT_object_pointer: <0x178>
<16c> DW_AT_GNU_all_call_sites: 1
<16c> DW_AT_sibling : <0x192>
<2><170>: Abbrev Number: 4 (DW_TAG_template_type_param)
<171> DW_AT_name : T1
<174> DW_AT_type : <0x136>
<2><178>: Abbrev Number: 12 (DW_TAG_formal_parameter)
<179> DW_AT_name : this
<17d> DW_AT_type : <0x148>
<181> DW_AT_artificial : 1
<181> DW_AT_location : 2 byte block: 91 68 (DW_OP_fbreg: -24)
<2><184>: Abbrev Number: 13 (DW_TAG_formal_parameter)
<185> DW_AT_name : t1
<188> DW_AT_decl_file : 1
<189> DW_AT_decl_line : 6
<18a> DW_AT_type : <0x13d>
<18e> DW_AT_location : 2 byte block: 91 60 (DW_OP_fbreg: -32)
...
But with -fdebug-types-section, we have:
...
<1><10e>: Abbrev Number: 9 (DW_TAG_subprogram)
<10f> DW_AT_specification: <0x18e>
<113> DW_AT_object_pointer: <0x139>
<117> DW_AT_low_pc : 0x4004ee
<11f> DW_AT_high_pc : 0x24
<127> DW_AT_frame_base : 1 byte block: 9c (DW_OP_call_frame_cfa)
<129> DW_AT_object_pointer: <0x139>
<12d> DW_AT_GNU_all_call_sites: 1
<12d> DW_AT_sibling : <0x153>
<2><131>: Abbrev Number: 3 (DW_TAG_template_type_param)
<132> DW_AT_name : T1
<135> DW_AT_type : <0xf7>
<2><139>: Abbrev Number: 10 (DW_TAG_formal_parameter)
<13a> DW_AT_name : this
<13e> DW_AT_type : <0x109>
<142> DW_AT_artificial : 1
<142> DW_AT_location : 2 byte block: 91 68 (DW_OP_fbreg: -24)
<2><145>: Abbrev Number: 11 (DW_TAG_formal_parameter)
<146> DW_AT_name : t1
<149> DW_AT_decl_file : 1
<14a> DW_AT_decl_line : 6
<14b> DW_AT_type : <0xfe>
<14f> DW_AT_location : 2 byte block: 91 60 (DW_OP_fbreg: -32)
<1><181>: Abbrev Number: 14 (DW_TAG_class_type)
<182> DW_AT_name : (indirect string, offset: 0x202): G<int>
<186> DW_AT_signature : signature: 0x239eaf153e8777a
<18e> DW_AT_declaration : 1
<2><18e>: Abbrev Number: 15 (DW_TAG_subprogram)
<18f> DW_AT_external : 1
<18f> DW_AT_name : mul<double>
<193> DW_AT_decl_file : 1
<194> DW_AT_decl_line : 6
<195> DW_AT_linkage_name: _ZN1GIiE3mulIdEEiT_
<199> DW_AT_type : <0xf0>
<19d> DW_AT_accessibility: 1 (public)
<19e> DW_AT_declaration : 1
<19e> DW_AT_object_pointer: <0x1a2>
<3><1a2>: Abbrev Number: 16 (DW_TAG_formal_parameter)
<1a3> DW_AT_type : <0x103>
<1a7> DW_AT_artificial : 1
...
So, the DIE at 0x18e is missing the DW_TAG_template_type_param and the
DW_TAG_formal_parameter for the double arg.
