From b2c007b87dcd5db5d59447de2081777aea66f35f Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 12 Apr 2022 17:17:20 +0100
Subject: [PATCH] libstdc++: shrink-to-fit in
std::basic_stacktrace::current(skip, max)
If a large stacktrace is reduced to a max depth that is less than half
the capacity it will now be reallocated to remove the unused capacity.
libstdc++-v3/ChangeLog:
* include/std/stacktrace (basic_stacktrace::current): Reallocate
a smaller container if the unused capacity is larger than the
used size.
---
libstdc++-v3/include/std/stacktrace | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/std/stacktrace b/libstdc++-v3/include/std/stacktrace
index 382d900a822f..98ce92311501 100644
--- a/libstdc++-v3/include/std/stacktrace
+++ b/libstdc++-v3/include/std/stacktrace
@@ -289,7 +289,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if (__err < 0)
__ret._M_clear();
else if (__ret.size() > __max_depth)
- __ret._M_impl._M_resize(__max_depth, __ret._M_alloc);
+ {
+ __ret._M_impl._M_resize(__max_depth, __ret._M_alloc);
+
+ if (__ret._M_impl._M_capacity / 2 >= __max_depth)
+ {
+ // shrink to fit
+ _Impl __tmp = __ret._M_impl._M_clone(__ret._M_alloc);
+ if (__tmp._M_capacity)
+ {
+ __ret._M_clear();
+ __ret._M_impl = __tmp;
+ }
+ }
+ }
}
return __ret;
}
--
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