Format string checking incorrectly assumes repeated evaluation of string literal will produce the same pointer #4177
Comments
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Applied the patch (with a small tweak) in cacc310. Thanks! |
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@vitaut FMT_CONSTEXPR auto sv = string_view(S());? Instead of FMT_CONSTEXPR auto sv = string_view(s);?
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I don't think it matters much but since the object is already available, I don't see why we need to construct another one. |
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Adding a regression test: 1c5883b. |
Nevermind, I misinterpreted which is the current version of the code. You are right, we could use |
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I did some local test by rolling our fmtlib to ToT and building our project with ToT clang but still getting errors: and |
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I guess we should be using |
You mean |
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You would also need to remove the |
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With diff like this: The build passed. |
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Uploaded PR #4187 |
3 tasks
mtremer
pushed a commit
to ipfire/ipfire-2.x
that referenced
this issue
Feb 22, 2025
- Update from version 11.0.2 to 11.1.3
- Update of rootfile
- Changelog
11.1.3
- Fixed compilation on GCC 9.4 (fmtlib/fmt#4313).
- Worked around an internal compiler error when using C++20 modules with GCC
14.2 and earlier (fmtlib/fmt#4295).
- Worked around a bug in GCC 6 (fmtlib/fmt#4318).
- Fixed an issue caused by instantiating `formatter<const T>`
(fmtlib/fmt#4303,
fmtlib/fmt#4325). Thanks @timsong-cpp.
- Fixed formatting into `std::ostreambuf_iterator` when using format string
compilation (fmtlib/fmt#4309,
fmtlib/fmt#4312). Thanks @phprus.
- Restored a constraint on the map formatter so that it correctly reports as
unformattable when the element is (fmtlib/fmt#4326).
Thanks @timsong-cpp.
- Reduced the size of format specs (fmtlib/fmt#4298).
- Readded `args()` to `fmt::format_context`
(fmtlib/fmt#4307,
fmtlib/fmt#4310). Thanks @Erroneous1.
- Fixed a bogus MSVC warning (fmtlib/fmt#4314,
fmtlib/fmt#4322). Thanks @ZehMatt.
- Fixed a pedantic mode error in the CMake config
(fmtlib/fmt#4327). Thanks @rlalik.
11.1.2
- Fixed ABI compatibility with earlier 11.x versions
(fmtlib/fmt#4292).
- Added `wchar_t` support to the `std::bitset` formatter
(fmtlib/fmt#4285,
fmtlib/fmt#4286,
fmtlib/fmt#4289,
fmtlib/fmt#4290). Thanks @phprus.
- Prefixed CMake components with `fmt-` to simplify usage of {fmt} via
`add_subdirectory` (fmtlib/fmt#4283).
- Updated docs for meson (fmtlib/fmt#4291).
Thanks @trim21.
- Fixed a compilation error in chrono on nvcc
(fmtlib/fmt#4297,
fmtlib/fmt#4301). Thanks @breyerml.
- Fixed various warnings
(fmtlib/fmt#4288,
fmtlib/fmt#4299). Thanks @GamesTrap and @edo9300.
11.1.1
- Fixed ABI compatibility with earlier 11.x versions
(fmtlib/fmt#4278).
- Defined CMake components (`core` and `doc`) to allow docs to be installed
separately (fmtlib/fmt#4276).
Thanks @carlsmedstad.
11.1.0
- Improved C++20 module support
(fmtlib/fmt#4081,
fmtlib/fmt#4083,
fmtlib/fmt#4084,
fmtlib/fmt#4152,
fmtlib/fmt#4153,
fmtlib/fmt#4169,
fmtlib/fmt#4190,
fmtlib/fmt#4234,
fmtlib/fmt#4239).
Thanks @kamrann and @Arghnews.
- Reduced debug (unoptimized) binary code size and the number of template
instantiations when passing formatting arguments. For example, unoptimized
binary code size for `fmt::print("{}", 42)` was reduced by ~40% on GCC and
~60% on clang (x86-64).
GCC:
- Before: 161 instructions of which 105 are in reusable functions
([godbolt](https://www.godbolt.org/z/s9bGoo4ze)).
- After: 116 instructions of which 60 are in reusable functions
([godbolt](https://www.godbolt.org/z/r7GGGxMs6)).
Clang:
- Before: 310 instructions of which 251 are in reusable functions
([godbolt](https://www.godbolt.org/z/Ts88b7M9o)).
- After: 194 instructions of which 135 are in reusable functions
([godbolt](https://www.godbolt.org/z/vcrjP8ceW)).
- Added an experimental `fmt::writer` API that can be used for writing to
different destinations such as files or strings
(fmtlib/fmt#2354).
For example ([godbolt](https://www.godbolt.org/z/rWoKfbP7e)):
```c++
#include <fmt/os.h>
void write_text(fmt::writer w) {
w.print("The answer is {}.", 42);
}
int main() {
// Write to FILE.
write_text(stdout);
// Write to fmt::ostream.
auto f = fmt::output_file("myfile");
write_text(f);
// Write to std::string.
auto sb = fmt::string_buffer();
write_text(sb);
std::string s = sb.str();
}
```
- Added width and alignment support to the formatter of `std::error_code`.
- Made `std::expected<void, E>` formattable
(fmtlib/fmt#4145,
fmtlib/fmt#4148).
For example ([godbolt](https://www.godbolt.org/z/hrj5c6G86)):
```c++
fmt::print("{}", std::expected<void, int>());
```
prints
```
expected()
```
Thanks @phprus.
- Made `fmt::is_formattable<void>` SFINAE-friendly
(fmtlib/fmt#4147).
- Added support for `_BitInt` formatting when using clang
(fmtlib/fmt#4007,
fmtlib/fmt#4072,
fmtlib/fmt#4140,
fmtlib/fmt#4173,
fmtlib/fmt#4176).
For example ([godbolt](https://www.godbolt.org/z/KWjbWec5z)):
```c++
using int42 = _BitInt(42);
fmt::print("{}", int42(100));
```
Thanks @Arghnews.
- Added the `n` specifier for tuples and pairs
(fmtlib/fmt#4107). Thanks @someonewithpc.
- Added support for tuple-like types to `fmt::join`
(fmtlib/fmt#4226,
fmtlib/fmt#4230). Thanks @phprus.
- Made more types formattable at compile time
(fmtlib/fmt#4127). Thanks @AnthonyVH.
- Implemented a more efficient compile-time `fmt::formatted_size`
(fmtlib/fmt#4102,
fmtlib/fmt#4103). Thanks @phprus.
- Fixed compile-time formatting of some string types
(fmtlib/fmt#4065). Thanks @torshepherd.
- Made compiled version of `fmt::format_to` work with
`std::back_insert_iterator<std::vector<char>>`
(fmtlib/fmt#4206,
fmtlib/fmt#4211). Thanks @phprus.
- Added a formatter for `std::reference_wrapper`
(fmtlib/fmt#4163,
fmtlib/fmt#4164). Thanks @yfeldblum and @phprus.
- Added experimental padding support (glibc `strftime` extension) to `%m`, `%j`
and `%Y` (fmtlib/fmt#4161). Thanks @KKhanhH.
- Made microseconds formatted as `us` instead of `µs` if the Unicode support is
disabled (fmtlib/fmt#4088).
- Fixed an unreleased regression in transcoding of surrogate pairs
(fmtlib/fmt#4094,
fmtlib/fmt#4095). Thanks @phprus.
- Made `fmt::appender` satisfy `std::output_iterator` concept
(fmtlib/fmt#4092,
fmtlib/fmt#4093). Thanks @phprus.
- Made `std::iterator_traits<fmt::appender>` standard-conforming
(fmtlib/fmt#4185). Thanks @CaseyCarter.
- Made it easier to reuse `fmt::formatter<std::string_view>` for types with
an implicit conversion to `std::string_view`
(fmtlib/fmt#4036,
fmtlib/fmt#4055). Thanks @Arghnews.
- Made it possible to disable `<filesystem>` use via `FMT_CPP_LIB_FILESYSTEM`
for compatibility with some video game console SDKs, e.g. Nintendo Switch SDK
(fmtlib/fmt#4257,
fmtlib/fmt#4258,
fmtlib/fmt#4259). Thanks @W4RH4WK and @phprus.
- Fixed compatibility with platforms that use 80-bit `long double`
(fmtlib/fmt#4245,
fmtlib/fmt#4246). Thanks @jsirpoma.
- Added support for UTF-32 code units greater than `0xFFFF` in fill
(fmtlib/fmt#4201).
- Fixed handling of legacy encodings on Windows with GCC
(fmtlib/fmt#4162).
- Made `fmt::to_string` take `fmt::basic_memory_buffer` by const reference
(fmtlib/fmt#4261,
fmtlib/fmt#4262). Thanks @sascha-devel.
- Added `fmt::dynamic_format_arg_store::size`
(fmtlib/fmt#4270). Thanks @hannes-harnisch.
- Removed the ability to control locale usage via an undocumented
`FMT_STATIC_THOUSANDS_SEPARATOR` in favor of `FMT_USE_LOCALE`.
- Renamed `FMT_EXCEPTIONS` to `FMT_USE_EXCEPTIONS` for consistency with other
similar macros.
- Improved include directory ordering to reduce the chance of including
incorrect headers when using multiple versions of {fmt}
(fmtlib/fmt#4116). Thanks @cdzhan.
- Made it possible to compile a subset of {fmt} without the C++ runtime.
- Improved documentation and README
(fmtlib/fmt#4066,
fmtlib/fmt#4117,
fmtlib/fmt#4203,
fmtlib/fmt#4235). Thanks @zyctree and @nikola-sh.
- Improved the documentation generator (fmtlib/fmt#4110,
fmtlib/fmt#4115). Thanks @rturrado.
- Improved CI (fmtlib/fmt#4155,
fmtlib/fmt#4151). Thanks @phprus.
- Fixed various warnings and compilation issues
(fmtlib/fmt#2708,
fmtlib/fmt#4091,
fmtlib/fmt#4109,
fmtlib/fmt#4113,
fmtlib/fmt#4125,
fmtlib/fmt#4129,
fmtlib/fmt#4130,
fmtlib/fmt#4131,
fmtlib/fmt#4132,
fmtlib/fmt#4133,
fmtlib/fmt#4144,
fmtlib/fmt#4150,
fmtlib/fmt#4158,
fmtlib/fmt#4159,
fmtlib/fmt#4160,
fmtlib/fmt#4170,
fmtlib/fmt#4177,
fmtlib/fmt#4187,
fmtlib/fmt#4188,
fmtlib/fmt#4194,
fmtlib/fmt#4200,
fmtlib/fmt#4205,
fmtlib/fmt#4207,
fmtlib/fmt#4208,
fmtlib/fmt#4210,
fmtlib/fmt#4220,
fmtlib/fmt#4231,
fmtlib/fmt#4232,
fmtlib/fmt#4233,
fmtlib/fmt#4236,
fmtlib/fmt#4267,
fmtlib/fmt#4271).
Thanks @torsten48, @Arghnews, @tinfoilboy, @aminya, @Ottani, @zeroomega,
@c4v4, @kongy, @vinayyadav3016, @sergio-nsk, @phprus and @YexuanXiao.
Signed-off-by: Adolf Belka <[email protected]>
Signed-off-by: Michael Tremer <[email protected]>
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In the
fstringconstructor from a type that is convertible to string view, thesargument is passed to two different functions, which both internally convert it to astring_view. Thissargument is frequently created by theFMT_STRINGmacro which has a conversion tostring_viewthat evaluates a string literal expression.Each evaluation of a string literal expression can produce a different pointer. Therefore it is not correct to assume that the two conversions of
sto astring_viewproduce relatedstring_views, but the code does assume this. Historically, compilers have let you get away with this in compile-time evaluation, but clang recently gained a more strict implementation of this rule and now rejects.I think the fix is probably to do the same thing in this constructor that is done a few lines below in the next constructor:
template <typename S, FMT_ENABLE_IF(std::is_convertible<const S&, string_view>::value)> FMT_CONSTEVAL FMT_ALWAYS_INLINE fstring(const S& s) : str(s) { if (FMT_USE_CONSTEVAL) + FMT_CONSTEXPR auto sv = string_view(S()); - detail::parse_format_string<char>(s, checker(s, arg_pack())); + detail::parse_format_string<char>(sv, checker(sv, arg_pack())); #ifdef FMT_ENFORCE_COMPILE_STRING static_assert( FMT_USE_CONSTEVAL && sizeof(s) != 0, "FMT_ENFORCE_COMPILE_STRING requires format strings to use FMT_STRING"); #endif } template <typename S, FMT_ENABLE_IF(std::is_base_of<detail::compile_string, S>::value&& std::is_same<typename S::char_type, char>::value)> FMT_ALWAYS_INLINE fstring(const S&) : str(S()) { FMT_CONSTEXPR auto sv = string_view(S()); FMT_CONSTEXPR int ignore = (parse_format_string(sv, checker(sv, arg_pack())), 0); detail::ignore_unused(ignore); }The text was updated successfully, but these errors were encountered: