On Wed, 30 Nov 2022 at 18:00, François Dumont <frs.dum...@gmail.com> wrote:
>
> On 30/11/22 14:07, Jonathan Wakely wrote:
> > On Wed, 30 Nov 2022 at 11:57, Jonathan Wakely <jwak...@redhat.com> wrote:
> >>
> >>
> >> On Wed, 30 Nov 2022 at 11:54, Jonathan Wakely <jwak...@redhat.com> wrote:
> >>>
> >>>
> >>> On Wed, 30 Nov 2022 at 06:04, François Dumont via Libstdc++
> >>> <libstd...@gcc.gnu.org> wrote:
> >>>> Good catch, then we also need this patch.
> >>>
> >>> Is it worth printing an error? If we can't show the backtrace because of
> >>> an error, we can just print nothing there.
>
> No strong opinion on that but if we do not print anything the output
> will be:
>
> Backtrace:
>
> Error: ...
>
> I just considered that it did not cost much to report the issue to the
> user that defined _GLIBCXX_DEBUG_BACKTRACE and so is expecting a backtrace.
>
> Maybe printing "Backtrace:\n" could be done in the normal callback
> leaving the user with the feeling that _GLIBCXX_DEBUG_BACKTRACE does not
> work.
OK, how's this?
Tested x86_64-linux.
commit aadf83283f0d3e1d473ac17595ba73d0210bb9ba
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Wed Nov 30 12:32:53 2022
libstdc++: Pass error handler to libbacktrace functions
Also pass threaded=1 to __glibcxx_backtrace_create_state and remove some
of the namespace scope declarations in the header.
Co-authored-by: François Dumont <frs.dum...@gmail.com>
libstdc++-v3/ChangeLog:
* include/debug/formatter.h [_GLIBCXX_DEBUG_BACKTRACE]
(_Error_formatter::_Error_formatter): Pass error handler to
__glibcxx_backtrace_create_state. Pass 1 for threaded argument.
(_Error_formatter::_S_err): Define empty function.
* src/c++11/debug.cc (_Error_formatter::_M_error): Pass error
handler to __glibcxx_backtrace_full.
diff --git a/libstdc++-v3/include/debug/formatter.h
b/libstdc++-v3/include/debug/formatter.h
index f120163c6d4..e8a83a21bde 100644
--- a/libstdc++-v3/include/debug/formatter.h
+++ b/libstdc++-v3/include/debug/formatter.h
@@ -32,32 +32,17 @@
#include <bits/c++config.h>
#if _GLIBCXX_HAVE_STACKTRACE
-struct __glibcxx_backtrace_state;
-
extern "C"
{
- __glibcxx_backtrace_state*
+ struct __glibcxx_backtrace_state*
__glibcxx_backtrace_create_state(const char*, int,
void(*)(void*, const char*, int),
void*);
-
- typedef int (*__glibcxx_backtrace_full_callback) (
- void*, __UINTPTR_TYPE__, const char *, int, const char*);
-
- typedef void (*__glibcxx_backtrace_error_callback) (
- void*, const char*, int);
-
- typedef int (*__glibcxx_backtrace_full_func) (
- __glibcxx_backtrace_state*, int,
- __glibcxx_backtrace_full_callback,
- __glibcxx_backtrace_error_callback,
- void*);
-
int
__glibcxx_backtrace_full(
- __glibcxx_backtrace_state*, int,
- __glibcxx_backtrace_full_callback,
- __glibcxx_backtrace_error_callback,
+ struct __glibcxx_backtrace_state*, int,
+ int (*)(void*, __UINTPTR_TYPE__, const char *, int, const char*),
+ void (*)(void*, const char*, int),
void*);
}
#endif
@@ -609,10 +594,10 @@ namespace __gnu_debug
, _M_function(__function)
#if _GLIBCXX_HAVE_STACKTRACE
# ifdef _GLIBCXX_DEBUG_BACKTRACE
- , _M_backtrace_state(__glibcxx_backtrace_create_state(0, 0, 0, 0))
+ , _M_backtrace_state(__glibcxx_backtrace_create_state(0, 1, _S_err, 0))
, _M_backtrace_full(&__glibcxx_backtrace_full)
# else
- , _M_backtrace_state()
+ , _M_backtrace_state(0)
# endif
#endif
{ }
@@ -631,8 +616,12 @@ namespace __gnu_debug
const char* _M_text;
const char* _M_function;
#if _GLIBCXX_HAVE_STACKTRACE
- __glibcxx_backtrace_state* _M_backtrace_state;
- __glibcxx_backtrace_full_func _M_backtrace_full;
+ struct __glibcxx_backtrace_state* _M_backtrace_state;
+ // TODO: Remove _M_backtrace_full after __glibcxx_backtrace_full is moved
+ // from libstdc++_libbacktrace.a to libstdc++.so:
+ __decltype(&__glibcxx_backtrace_full) _M_backtrace_full;
+
+ static void _S_err(void*, const char*, int) { }
#endif
public:
diff --git a/libstdc++-v3/src/c++11/debug.cc b/libstdc++-v3/src/c++11/debug.cc
index 9eda38023f7..83996ffe622 100644
--- a/libstdc++-v3/src/c++11/debug.cc
+++ b/libstdc++-v3/src/c++11/debug.cc
@@ -1141,6 +1141,23 @@ namespace
return ret;
}
+
+ void
+ print_backtrace_error(void* data, const char* msg, int errnum)
+ {
+ PrintContext& ctx = *static_cast<PrintContext*>(data);
+
+ print_literal(ctx, "Backtrace unavailable: ");
+ print_word(ctx, msg ? msg : "<unknown error>");
+ if (errnum > 0)
+ {
+ char buf[64];
+ int written = __builtin_sprintf(buf, " (errno=%d)\n", errnum);
+ print_word(ctx, buf, written);
+ }
+ else
+ print_literal(ctx, "\n");
+ }
#endif
}
@@ -1193,7 +1210,7 @@ namespace __gnu_debug
{
print_literal(ctx, "Backtrace:\n");
_M_backtrace_full(
- _M_backtrace_state, 1, print_backtrace, nullptr, &ctx);
+ _M_backtrace_state, 1, print_backtrace, print_backtrace_error, &ctx);
ctx._M_first_line = true;
print_literal(ctx, "\n");
}
