On Fri, 8 May 2026, Dragon Archer wrote:
> PR libstdc++/125228
>
> This patch replaces the uses of `assert` in ryu and debug.cc with
> `__glibcxx_assert`, and removed their direct dependency on `<cassert>`.
> To avoid modifying the third-party ryu headers, this patch use
> `#pragma push_macro` / `#pragma pop_macro` to locally
> redefine `assert` to `__glibcxx_assert` when including the ryu headers.
>
> libstdc++-v3/ChangeLog:
>
> PR libstdc++/125228
> * src/c++11/debug.cc: Replace assert with __glibcxx_assert,
> and remove the include of <cassert>.
> * src/c++17/floating_to_chars.cc: Likewise, but redefine
> assert as __glibcxx_assert using pragma push/pop_macro.
>
> --
>
> From 76f866652f9a7e2fc4faf012f6b356e9a85ecb8d Mon Sep 17 00:00:00 2001
> From: dragon-archer <[email protected]>
> Date: Fri, 8 May 2026 19:14:49 +0800
> Subject: [PATCH] libstdc++: Use __glibcxx_assert instead of assert
>
> Unlike `__glibcxx_assert` which is guarded
> by `_GLIBCXX_ASSERTIONS` and enabled only in Debug
> build of libstdc++, `assert` is either always enabled, or
> always disabled if manually defining `NDEBUG` before
> `#include <cassert>` or `#include <assert.h>`. This not
> only makes `assert` inflexible, but also introduces extra
> runtime overhead and/or increased binary size in Release
> builds.
>
> Uses of `assert` without `NDEBUG` introduces `__FILE__`
> into the final library, and can be easily found using
> `string`
Seems reasonable to me (though pragma push/pop_macro don't seem strictly
necessary as Jonathan pointed out).
Though in theory I guess there's a risk of a performance regression by
removing an assert in Ryu, if the compiler relies on an assert condition
to be true in order to safely apply an important optimization.
Just wondering, is there a legit problem/concern with __FILE__ appearing
in the final library or is it a matter of QoI (which I agree with)?
>
> This is a long standing issue, dating from at least GCC
> 8.5.0 to latest GCC 16.1.0
> ---
> libstdc++-v3/src/c++11/debug.cc | 33 ++++++++++-----------
> libstdc++-v3/src/c++17/floating_to_chars.cc | 5 +++-
> 2 files changed, 20 insertions(+), 18 deletions(-)
>
> diff --git a/libstdc++-v3/src/c++11/debug.cc b/libstdc++-v3/src/c++11/debug.cc
> index 7049d5f1238..9a36bdfabb9 100644
> --- a/libstdc++-v3/src/c++11/debug.cc
> +++ b/libstdc++-v3/src/c++11/debug.cc
> @@ -33,7 +33,6 @@
> #include <debug/safe_local_iterator.h>
> #include <debug/vector>
>
> -#include <cassert>
> #include <cstdio> // for std::fprintf, stderr
> #include <cstdlib> // for std::abort
> #include <cctype> // for std::isspace.
> @@ -888,7 +887,7 @@ namespace
> void
> print_named_name(PrintContext& ctx, const _Parameter::_Named& named)
> {
> - assert(named._M_name);
> + __glibcxx_assert(named._M_name);
> pretty_print(ctx, named._M_name, print_word);
> }
>
> @@ -985,7 +984,7 @@ namespace
> print_iterator_state(ctx, iterator);
> else if (__builtin_strcmp(fname, "sequence") == 0)
> {
> - assert(iterator._M_sequence);
> + __glibcxx_assert(iterator._M_sequence);
> print_address(ctx, iterator._M_sequence);
> }
> else if (__builtin_strcmp(fname, "seq_type") == 0)
> @@ -999,43 +998,43 @@ namespace
> void
> print_field(PrintContext& ctx, const _Parameter& param, const char* fname)
> {
> - assert(param._M_kind != _Parameter::__unused_param);
> + __glibcxx_assert(param._M_kind != _Parameter::__unused_param);
>
> const auto& variant = param._M_variant;
> switch (param._M_kind)
> {
> case _Parameter::__iterator:
> if (!print_iterator_field(ctx, fname, variant._M_iterator))
> - assert(false);
> + __glibcxx_assert(false);
> break;
>
> case _Parameter::__sequence:
> if (!print_instance_field(ctx, fname, variant._M_sequence))
> - assert(false);
> + __glibcxx_assert(false);
> break;
>
> case _Parameter::__integer:
> if (!print_named_field(ctx, fname, variant._M_integer))
> - assert(false);
> + __glibcxx_assert(false);
> break;
>
> case _Parameter::__string:
> if (!print_named_field(ctx, fname, variant._M_string))
> - assert(false);
> + __glibcxx_assert(false);
> break;
>
> case _Parameter::__instance:
> if (!print_instance_field(ctx, fname, variant._M_instance))
> - assert(false);
> + __glibcxx_assert(false);
> break;
>
> case _Parameter::__iterator_value_type:
> if (!print_type_field(ctx, fname, variant._M_iterator_value_type))
> - assert(false);
> + __glibcxx_assert(false);
> break;
>
> default:
> - assert(false);
> + __glibcxx_assert(false);
> break;
> }
> }
> @@ -1198,9 +1197,9 @@ namespace
> }
>
> // Get the parameter number
> - assert(*str >= '1' && *str <= '9');
> + __glibcxx_assert(*str >= '1' && *str <= '9');
> size_t param_index = *str - '0' - 1;
> - assert(param_index < num_parameters);
> + __glibcxx_assert(param_index < num_parameters);
> const auto& param = parameters[param_index];
>
> // '.' separates the parameter number from the field
> @@ -1208,7 +1207,7 @@ namespace
> ++str;
> if (*str != '.')
> {
> - assert(*str == ';');
> + __glibcxx_assert(*str == ';');
> ++str;
> if (param._M_kind == _Parameter::__integer)
> print_integer(ctx, param._M_variant._M_integer._M_value);
> @@ -1226,8 +1225,8 @@ namespace
> ++str;
> while (*str != ';')
> {
> - assert(*str);
> - assert(field_idx < max_field_len - 1);
> + __glibcxx_assert(*str);
> + __glibcxx_assert(field_idx < max_field_len - 1);
> field[field_idx++] = *str++;
> }
> ++str;
> @@ -1382,7 +1381,7 @@ namespace __gnu_debug
> print_literal(ctx, "Error: ");
>
> // Print the error message
> - assert(_M_text);
> + __glibcxx_assert(_M_text);
> print_string(ctx, _M_text, -1, _M_parameters, _M_num_parameters);
> print_literal(ctx, ".\n");
>
> diff --git a/libstdc++-v3/src/c++17/floating_to_chars.cc
> b/libstdc++-v3/src/c++17/floating_to_chars.cc
> index 9bddffd70ff..264e520e187 100644
> --- a/libstdc++-v3/src/c++17/floating_to_chars.cc
> +++ b/libstdc++-v3/src/c++17/floating_to_chars.cc
> @@ -26,7 +26,6 @@
>
> #include <bit>
> #include <cfenv>
> -#include <cassert>
> #include <cmath>
> #include <cstdio>
> #include <cstring>
> @@ -106,6 +105,9 @@ namespace
>
> namespace ryu
> {
> +#pragma push_macro("assert")
> +#undef assert
> +#define assert __glibcxx_assert
> #include "ryu/common.h"
> #include "ryu/digit_table.h"
> #include "ryu/d2s_intrinsics.h"
> @@ -123,6 +125,7 @@ namespace
> # include "ryu/ryu_generic_128.h"
> # include "ryu/generic_128.c"
> } // namespace generic128
> +#pragma pop_macro("assert")
>
> using generic128::floating_decimal_128;
> using generic128::generic_binary_to_decimal;
> --
> 2.54.0.windows.1
>
>
>
