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* [Bug gdb/17450] New: resolve_dynamic_type_internal misunderstands check_typedef -> internal error
@ 2014-10-01 17:57 dje at google dot com
2014-11-27 0:23 ` [Bug gdb/17450] " dje at google dot com
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: dje at google dot com @ 2014-10-01 17:57 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=17450
Bug ID: 17450
Summary: resolve_dynamic_type_internal misunderstands
check_typedef -> internal error
Product: gdb
Version: HEAD
Status: NEW
Severity: normal
Priority: P2
Component: gdb
Assignee: unassigned at sourceware dot org
Reporter: dje at google dot com
Clang is emitting no bounds info for the "x" in
class c { char x[0]; char more_x[42]; };
This causes has_static_range for "x" to return false (lower bound is defaulted
to zero, upper bound is unknown), which in turn causes is_dynamic_type to
return true and we enter resolve_dynamic_type (which is just a wrapper on
resolve_dynamic_type_internal).
In the example at hand (I don't have an easy to provide testcase, at least not
yet), the type is defined in another CU so what resolve_dynamic_type gets is an
opaque type. We then hit this assert in resolve_dynamic_struct and crash:
gdb_assert (TYPE_NFIELDS (type) > 0);
resolve_dynamic_type_internal seems to not understand that check_typedef has
(at least) two main purposes:
1) check for typedefs (duh ... :-)),
2) AND resolve opaque types.
It's easy to understand this happening given how poorly named check_typedef is.
static struct type *
resolve_dynamic_type_internal (struct type *type, CORE_ADDR addr,
int top_level)
{
struct type *real_type = check_typedef (type);
struct type *resolved_type = type;
const struct dynamic_prop *prop;
CORE_ADDR value;
if (!is_dynamic_type_internal (real_type, top_level))
return type;
switch (TYPE_CODE (type))
{
...
case TYPE_CODE_STRUCT:
resolved_type = resolve_dynamic_struct (type, addr);
break;
}
...
}
Note that we've called check_typedef, BUT we're passing type to
resolve_dynamic_struct not real_type. If type is an opaque type we in fact do
want to pass real_type to resolve_dynamic_struct.
Either that or call check_typedef again in resolve_dynamic_struct. Since this
collection of functions is all just implementation detail for
resolve_dynamic_type I'm ok with not sprinkling calls to check_typedef
everywhere it might be needed (and in fact since the function is so badly named
sprinkling it about doesn't improve readability). It would be reasonable to
create a resolve_opaque_type function that handles this part of what
check_typedef does, and use that instead, but I'm ok with just passing
real_type to resolve_dynamic_struct here.
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* [Bug gdb/17450] resolve_dynamic_type_internal misunderstands check_typedef -> internal error
2014-10-01 17:57 [Bug gdb/17450] New: resolve_dynamic_type_internal misunderstands check_typedef -> internal error dje at google dot com
@ 2014-11-27 0:23 ` dje at google dot com
2014-11-27 23:09 ` jan.kratochvil at redhat dot com
2014-11-27 23:49 ` dje at google dot com
2 siblings, 0 replies; 4+ messages in thread
From: dje at google dot com @ 2014-11-27 0:23 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=17450
--- Comment #1 from dje at google dot com ---
See also PR 17642
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* [Bug gdb/17450] resolve_dynamic_type_internal misunderstands check_typedef -> internal error
2014-10-01 17:57 [Bug gdb/17450] New: resolve_dynamic_type_internal misunderstands check_typedef -> internal error dje at google dot com
2014-11-27 0:23 ` [Bug gdb/17450] " dje at google dot com
@ 2014-11-27 23:09 ` jan.kratochvil at redhat dot com
2014-11-27 23:49 ` dje at google dot com
2 siblings, 0 replies; 4+ messages in thread
From: jan.kratochvil at redhat dot com @ 2014-11-27 23:09 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=17450
Jan Kratochvil <jan.kratochvil at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |jan.kratochvil at redhat dot com
Resolution|--- |DUPLICATE
--- Comment #2 from Jan Kratochvil <jan.kratochvil at redhat dot com> ---
I do not see how this is clang specific.
echo 'class c { char x[0]; char more_x[42]; };'|clang++ -c -g -o o.out -x c++ -
gdb ./o.out
does not crash for me. IMO there have to be at least two CUs to make there the
stub type but then it is PR 17642.
*** This bug has been marked as a duplicate of bug 17642 ***
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* [Bug gdb/17450] resolve_dynamic_type_internal misunderstands check_typedef -> internal error
2014-10-01 17:57 [Bug gdb/17450] New: resolve_dynamic_type_internal misunderstands check_typedef -> internal error dje at google dot com
2014-11-27 0:23 ` [Bug gdb/17450] " dje at google dot com
2014-11-27 23:09 ` jan.kratochvil at redhat dot com
@ 2014-11-27 23:49 ` dje at google dot com
2 siblings, 0 replies; 4+ messages in thread
From: dje at google dot com @ 2014-11-27 23:49 UTC (permalink / raw)
To: gdb-prs
https://sourceware.org/bugzilla/show_bug.cgi?id=17450
--- Comment #3 from dje at google dot com ---
Ahem.
Just because I report a bug I'm seeing with clang does not mean I'm claiming
the bug is clang specific.
Sheesh.
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end of thread, other threads:[~2014-11-27 23:49 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2014-10-01 17:57 [Bug gdb/17450] New: resolve_dynamic_type_internal misunderstands check_typedef -> internal error dje at google dot com
2014-11-27 0:23 ` [Bug gdb/17450] " dje at google dot com
2014-11-27 23:09 ` jan.kratochvil at redhat dot com
2014-11-27 23:49 ` dje at google dot com
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