With this change stacktrace entries always output the frame address, and
source file information no longer results in " at :0", e.g.
16# myfunc(int) at /tmp/bt.cc:48 [0x4008b7]
17# main at /tmp/bt.cc:61 [0x40091a]
18# __libc_start_call_main [0x7efc3d6d3574]
19# __libc_start_main@GLIBC_2.2.5 [0x7efc3d6d3627]
20# _start [0x400684]
This replaces the previous output:
16# myfunc(int) at /tmp/bt.cc:48
17# main at /tmp/bt.cc:61
18# __libc_start_call_main at :0
19# __libc_start_main@GLIBC_2.2.5 at :0
20# _start at :0
A change that is not visible in the examples above is that for a
non-empty stacktrace_entry, we now print "<unknown>" for the function
name if description() returns an empty string. For an empty (e.g.
default constructed) stacktrace_entry the entire string representation
is now "<unknown>" instead of an empty string.
Instead of printing "<unknown>" for the function name, we could set that
string in the stacktrace_entry::_Info object, so that description()
returns "<unknown>" and then operator<< wouldn't need to handle an empty
description() string. However, returning an empty string from that
function seems simpler for users to detect, rather than having to parse
"<unknown>".
We could also choose a different string for an empty stacktrace_entry,
maybe "<none>" or "<invalid>", but "<unknown>" seems good.
libstdc++-v3/ChangeLog:
* include/std/stacktrace
(operator<<(ostream&, const stacktrace_entry&)): Improve output
when description() or source_file() returns an empty string,
or the stacktrace_entry is invalid. Append frame address to
output.
(operator<<(ostream&, const basic_stacktrace<A>&)): Use the
size_type of the correct specialization.
Reviewed-by: Tomasz Kamiński <[email protected]>
Reviewed-by: Nathan Myers <[email protected]>
---
v3: always append the address to the output, instead of only when we
don't have a filename.
Tested x86_64-linux. Pushed to trunk.
libstdc++-v3/include/std/stacktrace | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)
diff --git a/libstdc++-v3/include/std/stacktrace
b/libstdc++-v3/include/std/stacktrace
index b9e260e19f89..587a163e9766 100644
--- a/libstdc++-v3/include/std/stacktrace
+++ b/libstdc++-v3/include/std/stacktrace
@@ -683,13 +683,32 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline ostream&
operator<<(ostream& __os, const stacktrace_entry& __f)
{
+ if (!__f) [[unlikely]]
+ return __os << "<unknown>";
+
string __desc, __file;
int __line;
- if (__f._M_get_info(&__desc, &__file, &__line))
+ if (__f._M_get_info(&__desc, &__file, &__line)) [[likely]]
{
- __os.width(4);
- __os << __desc << " at " << __file << ':' << __line;
+ __os << ' ';
+ if (__desc.empty()) [[unlikely]]
+ __os << "<unknown>";
+ else
+ __os << __desc;
+ if (!__file.empty()) [[likely]]
+ __os << " at " << __file << ':' << __line;
}
+
+ struct _Flag_guard // Set and restore hex format
+ {
+ _Flag_guard(ios& __s) : _M_ios(__s) { }
+ ~_Flag_guard() { _M_ios.setf(_M_f); }
+
+ ios& _M_ios;
+ ios::fmtflags _M_f = _M_ios.setf(ios::hex, ios::basefield);
+ };
+ _Flag_guard __g(__os);
+ __os << " [0x" << __f.native_handle() << ']';
return __os;
}
@@ -697,7 +716,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
inline ostream&
operator<<(ostream& __os, const basic_stacktrace<_Allocator>& __st)
{
- for (stacktrace::size_type __i = 0; __i < __st.size(); ++__i)
+ using size_type = typename basic_stacktrace<_Allocator>::size_type;
+ for (size_type __i = 0, __size = __st.size(); __i < __size; ++__i)
{
__os.width(4);
__os << __i << "# " << __st[__i] << '\n';
--
2.51.0
