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* [Bug c++/26525] New: DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable.
@ 2020-08-23 11:13 mark at klomp dot org
2020-08-24 19:52 ` [Bug c++/26525] " tromey at sourceware dot org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: mark at klomp dot org @ 2020-08-23 11:13 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=26525
Bug ID: 26525
Summary: DWARF5 class variables are not data members,
DW_TAG_member, but DW_TAG_variable.
Product: gdb
Version: unknown
Status: NEW
Severity: normal
Priority: P2
Component: c++
Assignee: unassigned at sourceware dot org
Reporter: mark at klomp dot org
Target Milestone: ---
Before DWARF5 there was no description of class variables (static data members)
and gcc would emit a DW_TAG_member for the class variables as if the were
non-static data members.
DWARF5, section 5.7.7 Class Variable Entries, says they are represented by a
DW_TAG_variable.
GCC has the following in dwarf2out.c:
/* For static data members, the declaration in the class is supposed
to have DW_TAG_member tag in DWARF{3,4} and we emit it for compatibility
also in DWARF2; the specification should still be DW_TAG_variable
referencing the DW_TAG_member DIE. */
if (declaration && class_scope_p (context_die) && dwarf_version < 5)
var_die = new_die (DW_TAG_member, context_die, decl);
else
var_die = new_die (DW_TAG_variable, context_die, decl);
if (origin != NULL)
add_abstract_origin_attribute (var_die, origin);
This means that when building with -gdwarf-5 there no longer is a DW_TAG_member
for static data members, but an DW_TAG_variable (which can be optimized away
when not referenced). This causes the following testsuite failures:
FAIL: gdb.base/ptype-offsets.exp: ptype/o static_member
FAIL: gdb.cp/constexpr-field.exp: print y
FAIL: gdb.cp/m-static.exp: static const int initialized nowhere (print field)
FAIL: gdb.cp/m-static.exp: ptype test4.nowhere
FAIL: gdb.cp/m-static.exp: print test4.nowhere.nowhere
FAIL: gdb.cp/m-static.exp: static const int initialized nowhere (whole struct)
FAIL: gdb.cp/m-static.exp: static const int initialized in class definition
FAIL: gdb.cp/m-static.exp: static const float initialized in class definition
FAIL: gdb.cp/m-static.exp: info variable everywhere
FAIL: gdb.cp/namespace.exp: print C::OtherFileClass::cOtherFileClassVar
FAIL: gdb.cp/namespace.exp: print ::C::OtherFileClass::cOtherFileClassVar
FAIL: gdb.cp/namespace.exp: ptype ::C::OtherFileClass typedefs
FAIL: gdb.cp/namespace.exp: ptype OtherFileClass typedefs
FAIL: gdb.cp/pr-574.exp: PR gdb/574
FAIL: gdb.cp/pr9167.exp: p b
FAIL: gdb.cp/templates.exp: ptype T5<int>
FAIL: gdb.cp/templates.exp: ptype t5i
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* [Bug c++/26525] DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable.
2020-08-23 11:13 [Bug c++/26525] New: DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable mark at klomp dot org
@ 2020-08-24 19:52 ` tromey at sourceware dot org
2020-08-24 20:04 ` tromey at sourceware dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: tromey at sourceware dot org @ 2020-08-24 19:52 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=26525
Tom Tromey <tromey at sourceware dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |tromey at sourceware dot org
--- Comment #1 from Tom Tromey <tromey at sourceware dot org> ---
(In reply to Mark Wielaard from comment #0)
> FAIL: gdb.base/ptype-offsets.exp: ptype/o static_member
The member isn't defined; this works:
diff --git a/gdb/testsuite/gdb.base/ptype-offsets.cc
b/gdb/testsuite/gdb.base/ptype-offsets.cc
index ddb009f1ae5..b686c9bdc3a 100644
--- a/gdb/testsuite/gdb.base/ptype-offsets.cc
+++ b/gdb/testsuite/gdb.base/ptype-offsets.cc
@@ -185,6 +185,8 @@ struct static_member
int abc;
};
+static_member static_member::Empty;
+
int
main (int argc, char *argv[])
{
> FAIL: gdb.cp/constexpr-field.exp: print y
This one is weird, the constexpr fields aren't described in the DWARF.
Maybe a test change is needed, see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90526#c1
> FAIL: gdb.cp/m-static.exp: static const int initialized nowhere (print field)
> FAIL: gdb.cp/m-static.exp: ptype test4.nowhere
> FAIL: gdb.cp/m-static.exp: print test4.nowhere.nowhere
> FAIL: gdb.cp/m-static.exp: static const int initialized nowhere (whole
> struct)
> FAIL: gdb.cp/m-static.exp: static const int initialized in class definition
> FAIL: gdb.cp/m-static.exp: static const float initialized in class definition
> FAIL: gdb.cp/m-static.exp: info variable everywhere
The "nowhere" failures are because this member is declared but not defined,
and gdb expects it to be <optimized out>. So arguably a compiler perhaps but
also just a weird test.
I didn't look at the rest. I think the basic feature is probably fine and
we're just seeing a difference between the test suite's expectations and what
gcc has started doing in some corner cases.
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* [Bug c++/26525] DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable.
2020-08-23 11:13 [Bug c++/26525] New: DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable mark at klomp dot org
2020-08-24 19:52 ` [Bug c++/26525] " tromey at sourceware dot org
@ 2020-08-24 20:04 ` tromey at sourceware dot org
2020-08-24 20:22 ` mark at klomp dot org
2020-08-26 14:46 ` tromey at sourceware dot org
3 siblings, 0 replies; 5+ messages in thread
From: tromey at sourceware dot org @ 2020-08-24 20:04 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=26525
--- Comment #2 from Tom Tromey <tromey at sourceware dot org> ---
Seems like Jakub thinks this is a gcc bug:
https://gcc.gnu.org/pipermail/gcc-patches/2020-August/552502.html
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* [Bug c++/26525] DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable.
2020-08-23 11:13 [Bug c++/26525] New: DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable mark at klomp dot org
2020-08-24 19:52 ` [Bug c++/26525] " tromey at sourceware dot org
2020-08-24 20:04 ` tromey at sourceware dot org
@ 2020-08-24 20:22 ` mark at klomp dot org
2020-08-26 14:46 ` tromey at sourceware dot org
3 siblings, 0 replies; 5+ messages in thread
From: mark at klomp dot org @ 2020-08-24 20:22 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=26525
Mark Wielaard <mark at klomp dot org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |jakub at redhat dot com,
| |jason at redhat dot com
Resolution|--- |INVALID
--- Comment #3 from Mark Wielaard <mark at klomp dot org> ---
(In reply to Tom Tromey from comment #2)
> Seems like Jakub thinks this is a gcc bug:
> https://gcc.gnu.org/pipermail/gcc-patches/2020-August/552502.html
And his proposed gcc patch turns all the FAILs from description into PASSes
(when building the gdb testsuite with -gdwarf-5 as default). So I'll close this
bug.
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* [Bug c++/26525] DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable.
2020-08-23 11:13 [Bug c++/26525] New: DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable mark at klomp dot org
` (2 preceding siblings ...)
2020-08-24 20:22 ` mark at klomp dot org
@ 2020-08-26 14:46 ` tromey at sourceware dot org
3 siblings, 0 replies; 5+ messages in thread
From: tromey at sourceware dot org @ 2020-08-26 14:46 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=26525
--- Comment #4 from Tom Tromey <tromey at sourceware dot org> ---
Thank you for trying this out, it was very helpful.
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end of thread, other threads:[~2020-08-26 14:46 UTC | newest]
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2020-08-23 11:13 [Bug c++/26525] New: DWARF5 class variables are not data members, DW_TAG_member, but DW_TAG_variable mark at klomp dot org
2020-08-24 19:52 ` [Bug c++/26525] " tromey at sourceware dot org
2020-08-24 20:04 ` tromey at sourceware dot org
2020-08-24 20:22 ` mark at klomp dot org
2020-08-26 14:46 ` tromey at sourceware dot org
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