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| author | Tom Tromey <tom@tromey.com> | 2022-04-02 09:54:40 -0600 |
|---|---|---|
| committer | Tom Tromey <tom@tromey.com> | 2022-04-18 09:34:55 -0600 |
| commit | 2390419d1cb72882110538e01e5586372df19657 (patch) | |
| tree | 184695bb4127c296ef8c1305e48fca1c0e27fdfb /gdb/valops.c | |
| parent | c67f4e53895da91ce7f2eff3544e9de02280f740 (diff) | |
| download | gdb-2390419d1cb72882110538e01e5586372df19657.zip gdb-2390419d1cb72882110538e01e5586372df19657.tar.gz gdb-2390419d1cb72882110538e01e5586372df19657.tar.bz2 | |
Fix C++ cast of derived class to base class
PR c++/28907 points out that casting from a derived class to a base
class fails in some situations. The problem turned out to be a
missing use of value_embedded_offset. One peculiarity here is that,
if you managed to construct a pointer-to-derived with an embedded
offset of 0, the cast would work -- for example, one of the two new
tests here passes without the patch.
This embedded offset stuff is an endless source of bugs. I wonder if
it's possible to get rid of it somehow.
Regression tested on x86-64 Fedora 34.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28907
Diffstat (limited to 'gdb/valops.c')
| -rw-r--r-- | gdb/valops.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/gdb/valops.c b/gdb/valops.c index 42a1213..e84cabf 100644 --- a/gdb/valops.c +++ b/gdb/valops.c @@ -274,7 +274,7 @@ value_cast_structs (struct type *type, struct value *v2) if (v) { /* Downcasting is possible (t1 is superclass of v2). */ - CORE_ADDR addr2 = value_address (v2); + CORE_ADDR addr2 = value_address (v2) + value_embedded_offset (v2); addr2 -= value_address (v) + value_embedded_offset (v); return value_at (type, addr2); |