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dd5ca05f47
Commit 5b7d941b90d1 ("gdb: add owner-related methods to struct type")
introduced a regression when running gdb.base/jit-reader-simple.exp and
others. A NULL pointer dereference happens here:
#3 0x0000557b7e9e8650 in gdbarch_obstack (arch=0x0) at /home/simark/src/binutils-gdb/gdb/gdbarch.c:484
#4 0x0000557b7ea5b138 in copy_type_recursive (objfile=0x614000006640, type=0x62100018da80, copied_types=0x62100018e280) at /home/simark/src/binutils-gdb/gdb/gdbtypes.c:5537
#5 0x0000557b7ea5dcbb in copy_type_recursive (objfile=0x614000006640, type=0x62100018e200, copied_types=0x62100018e280) at /home/simark/src/binutils-gdb/gdb/gdbtypes.c:5598
#6 0x0000557b802cef51 in preserve_one_value (value=0x6110000b3640, objfile=0x614000006640, copied_types=0x62100018e280) at /home/simark/src/binutils-gdb/gdb/value.c:2518
#7 0x0000557b802cf787 in preserve_values (objfile=0x614000006640) at /home/simark/src/binutils-gdb/gdb/value.c:2562
#8 0x0000557b7fbaf19b in reread_symbols () at /home/simark/src/binutils-gdb/gdb/symfile.c:2489
#9 0x0000557b7ec65d1d in run_command_1 (args=0x0, from_tty=1, run_how=RUN_NORMAL) at /home/simark/src/binutils-gdb/gdb/infcmd.c:439
#10 0x0000557b7ec67a97 in run_command (args=0x0, from_tty=1) at /home/simark/src/binutils-gdb/gdb/infcmd.c:546
This is inside a TYPE_ALLOC macro. The fact that gdbarch_obstack is
called means that the type is flagged as being arch-owned, but arch=0x0
means that type::arch returned NULL, probably meaning that the m_owner
field contains NULL.
If we look at the code before the problematic patch, in the
copy_type_recursive function, we see:
if (! TYPE_OBJFILE_OWNED (type))
return type;
...
TYPE_OBJFILE_OWNED (new_type) = 0;
TYPE_OWNER (new_type).gdbarch = get_type_arch (type);
The last two lines were replaced with:
new_type->set_owner (type->arch ());
get_type_arch and type->arch isn't the same thing: get_type_arch gets
the type's arch owner if it is arch-owned, and gets the objfile's arch
if the type is objfile owned. So it always returns non-NULL.
type->arch returns the type's arch if the type is arch-owned, else NULL.
So since the original type is objfile owned, it effectively made the new
type arch-owned (that is good) but set the owner to NULL (that is bad).
Fix this by using get_type_arch again there.
I spotted one other similar change in lookup_array_range_type, in the
original patch. But that one appears to be correct, as it is executed
only if the type is arch-owned.
Add some asserts in type::set_owner to ensure we never set a NULL owner.
That would have helped catch the issue a little bit earlier, so it could
help in the future.
gdb/ChangeLog:
* gdbtypes.c (copy_type_recursive): Use get_type_arch.
* gdbtypes.h (struct type) <set_owner>: Add asserts.
Change-Id: I5d8bc7bfc83b3abc579be0b5aadeae4241179a00
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