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author | Tom de Vries <tdevries@suse.de> | 2020-07-06 09:54:43 +0200 |
---|---|---|
committer | Tom de Vries <tdevries@suse.de> | 2020-07-06 09:54:43 +0200 |
commit | 947f7597788b646683cb37b2833ed1844ce7d1bc (patch) | |
tree | 7a827893cd11b07e5c874ebb2cf3acb794487f20 | |
parent | ddb43bab174c50656331e5460b18bd8e8be5f522 (diff) | |
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[gdb/tui,c++17] Fix NULL string_view in tui_partial_win_by_name
When building gdb with CFLAGS=-std=gnu17 and CXXFLAGS=-std=gnu++17 and running
test-case gdb.tui/new-layout.exp, we run into:
...
UNRESOLVED: gdb.tui/new-layout.exp: left window box after shrink (ll corner)
FAIL: gdb.tui/new-layout.exp: right window box after shrink (ll corner)
...
In a minimal form, we run into an abort when issuing a winheight command:
...
$ gdb -tui -ex "winheight src - 5"
<tui stuff>
Aborted (core dumped)
$
...
with this backtrace at the abort:
...
\#0 0x0000000000438db0 in std::char_traits<char>::length (__s=0x0)
at /usr/include/c++/9/bits/char_traits.h:335
\#1 0x000000000043b72e in std::basic_string_view<char, \
std::char_traits<char> >::basic_string_view (this=0x7fffffffd4f0, \
__str=0x0) at /usr/include/c++/9/string_view:124
\#2 0x000000000094971b in tui_partial_win_by_name (name="src")
at src/gdb/tui/tui-win.c:663
...
due to a NULL comparison which constructs a string_view object from NULL:
...
657 /* Answer the window represented by name. */
658 static struct tui_win_info *
659 tui_partial_win_by_name (gdb::string_view name)
660 {
661 struct tui_win_info *best = nullptr;
662
663 if (name != NULL)
...
In gdbsupport/gdb_string_view.h, we either use:
- gdb's copy of libstdc++-v3/include/experimental/string_view, or
- the standard implementation of string_view, when built with C++17 or later
(which in gcc's case comes from libstdc++-v3/include/std/string_view)
In the first case, there's support for constructing a string_view from a NULL
pointer:
...
/*constexpr*/ basic_string_view(const _CharT* __str)
: _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
_M_str{__str}
{ }
...
but in the second case, there's not:
...
__attribute__((__nonnull__)) constexpr
basic_string_view(const _CharT* __str) noexcept
: _M_len{traits_type::length(__str)},
_M_str{__str}
{ }
...
Fix this by removing the NULL comparison altogether.
Build on x86_64-linux with CFLAGS=-std=gnu17 and CXXFLAGS=-std=gnu++17, and
tested.
gdb/ChangeLog:
2020-07-06 Tom de Vries <tdevries@suse.de>
PR tui/26205
* tui/tui-win.c (tui_partial_win_by_name): Don't test for NULL name.
-rw-r--r-- | gdb/ChangeLog | 5 | ||||
-rw-r--r-- | gdb/tui/tui-win.c | 23 |
2 files changed, 15 insertions, 13 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 21dc3e2..b802641 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2020-07-06 Tom de Vries <tdevries@suse.de> + + PR tui/26205 + * tui/tui-win.c (tui_partial_win_by_name): Don't test for NULL name. + 2020-07-05 Tom de Vries <tdevries@suse.de> PR build/26187 diff --git a/gdb/tui/tui-win.c b/gdb/tui/tui-win.c index 336571f..f906b0d 100644 --- a/gdb/tui/tui-win.c +++ b/gdb/tui/tui-win.c @@ -660,21 +660,18 @@ tui_partial_win_by_name (gdb::string_view name) { struct tui_win_info *best = nullptr; - if (name != NULL) + for (tui_win_info *item : all_tui_windows ()) { - for (tui_win_info *item : all_tui_windows ()) - { - const char *cur_name = item->name (); + const char *cur_name = item->name (); - if (name == cur_name) - return item; - if (startswith (cur_name, name)) - { - if (best != nullptr) - error (_("Window name \"%*s\" is ambiguous"), - (int) name.size (), name.data ()); - best = item; - } + if (name == cur_name) + return item; + if (startswith (cur_name, name)) + { + if (best != nullptr) + error (_("Window name \"%*s\" is ambiguous"), + (int) name.size (), name.data ()); + best = item; } } |