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construct/include/ircd/assert.h

100 lines
3.2 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
// This header allows for the use of soft-assertions. It is included before
// the standard <assert.h> and these declarations will take precedence.
//
// These declarations exist because the system declarations may have
// __attribute__((noreturn)) and our only modification here is to remove
// that. Alternative definitions to the standard library also exist in
// ircd/assert.cc
#pragma once
#define HAVE_IRCD_ASSERT_H
/// This file has to be included prior to the standard library assert headers
#if defined(RB_ASSERT) && defined(_ASSERT_H_DECLS) && defined(RB_DEBUG)
#error "Do not include <assert.h> or <cassert> first."
#endif
/// Define an indicator for whether we override standard assert() behavior in
/// this build if the conditions are appropriate.
#if defined(RB_ASSERT) && !defined(NDEBUG)
#define _ASSERT_H_DECLS
#endif
// Our utils
namespace ircd
{
void debugtrap() noexcept;
template<class expr> void always_assert(expr&&) noexcept;
[[gnu::cold]] void print_assertion(const char *const &, const char *const &, const unsigned &, const char *const &) noexcept;
}
/// Override the standard assert behavior to take one of several different
/// actions as defined in our internal assert.cc unit. When trapping assert
/// is disabled this path will be used instead.
///
#if defined(RB_ASSERT) && !defined(RB_ASSERT_INTRINSIC)
extern "C" void
__attribute__((visibility("default")))
__assert_fail(const char *__assertion,
const char *__file,
unsigned int __line,
const char *__function);
#endif
/// Override the standard assert behavior, if enabled, to trap into the
/// debugger as close as possible to the offending site.
///
#if defined(RB_ASSERT) && defined(RB_ASSERT_INTRINSIC)
extern "C" // for clang
{
extern inline void
__attribute__((flatten, always_inline, gnu_inline, artificial))
__assert_fail(const char *__assertion,
const char *__file,
unsigned int __line,
const char *__function)
{
ircd::print_assertion(__assertion, __file, __line, __function);
ircd::debugtrap();
}
}
#endif
/// Intrinsic to halt execution for examination by a tracing debugger without
/// aborting the program.
///
extern inline void
__attribute__((always_inline, gnu_inline, artificial))
ircd::debugtrap()
noexcept
{
#if defined(__clang__)
static_assert(__has_builtin(__builtin_debugtrap));
__builtin_debugtrap();
#elif defined(__x86_64__)
__asm__ volatile ("int $3 # IRCd ASSERTION DEBUG TRAP !!! ");
#else
__builtin_trap();
#endif
}
/// Trap on false expression whether or not NDEBUG.
template<class expr>
extern inline void
__attribute__((always_inline, gnu_inline, artificial))
ircd::always_assert(expr&& x)
noexcept
{
if(__builtin_expect(!bool(x), 0))
debugtrap();
}