boostorg / boostorg/assert

Some way to support an a handler for `BOOST_ASSERT(_MSG)` that takes a `std::source_location`

Abierto
#42 1 comentario 1 reacción 0 asignados Ver en GitHub
Lenguaje dominante
C++
Estrellas
35
Forks
77
Métricas de merge de PR
Sin PR fusionados en 30 d

Descripción

Problem: Using `std::source_location` is more efficient than passing separate file/line/column/func info because the location is a single pointer to static storage, rather than 2 pointer + 2 const ints. That can result in codegen bloat, especially on platforms like Aarch64 where it takes multiple instructions to load a global pointer. Given the usecase of assertions, this is often used for very cold (hopefully never executed!) code that sits in the same function as hot code, so you often want to make it as small as possible to maximize icache and iTLB. Note that it is important to use `source_location` from `std::` rather than `boost::` because the `std::` flavor uses implementation techniques that are not available to userspace C++ to make it a single pointer to static storage.

Possible solution 1: Add a new macro like `BOOST_ENABLE_ASSERT_HANDLER_WITH_STD_SOURCE_LOCATION` to opt into a different handler API that takes `std::source_location`.

Possible solution 2: Give the user full control over the handler expression by just making the failure case be a macro call like `BOOST_ASSERT_FAILURE_HANDLER()` and `BOOST_ASSERT_MSG_FAILURE_HANDLER(msg)`. The only tricky issue is that you would likely need some way to inject declarations and #includes into global scope, but it may be reasonable to say that anyone who can use this facility correctly can probably also use `-include "my_boost_assert_prefix_header.h"`. This option also has the advantage for anyone who wants to use `__builtin_trap()` to get the ultimate code size reduction, while still checking asserts.

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Línea de trabajo

Comienza revisando la API del handler existente de BOOST_ASSERT y cómo se expande BOOST_ASSERT(_MSG). Compara la opción propuesta de handler con std::source_location con las macros personalizables BOOST_ASSERT_FAILURE_HANDLER() y BOOST_ASSERT_MSG_FAILURE_HANDLER(). Se considera terminado cuando exista un diseño de API aprobado por un maintainer y el alcance de implementación correspondiente.

Escrito por el modelo de indexación a partir del texto del issue.

Evaluación

Stack tecnológico
cpp
Área
testing-qa
Tipo de issue
Nueva funcionalidad
Dificultad
5/5
Tiempo estimado
Más de una semana
Estado de actividad
Estancado
Claridad
Necesita aclaración
Aptitud para principiantes
25/100

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