src/utils/assert.h

// Copyright 2017 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef SRC_UTILS_ASSERT_H_
#define SRC_UTILS_ASSERT_H_

#include <cstdlib>
#include <type_traits>

#include "src/utils/compiler.h"

// Dawn asserts to be used instead of the regular C stdlib assert function (if you don't use assert
// yet, you should start now!). In debug DAWN_ASSERT(condition) will trigger an error, otherwise in
// release it does nothing at runtime.
//
// In case of name clashes (with for example a testing library), you can define the
// DAWN_SKIP_ASSERT_SHORTHANDS to only define the DAWN_ prefixed macros.
//
// These asserts feature:
//     - Logging of the error with file, line and function information.
//     - Breaking in the debugger when an assert is triggered and a debugger is attached.
//     - Use the assert information to help the compiler optimizer in release builds.

// MSVC triggers a warning in /W4 for do {} while(0). SDL worked around this by using (0,0) and
// points out that it looks like an owl face.
#if DAWN_COMPILER_IS(MSVC)
#define DAWN_ASSERT_LOOP_CONDITION (0, 0)
#else
#define DAWN_ASSERT_LOOP_CONDITION (0)
#endif

// DAWN_ASSERT_CALLSITE_HELPER generates the actual assert code. In Debug it does what you would
// expect of an assert and in release it tries to give hints to make the compiler generate better
// code.
#if defined(DAWN_ENABLE_ASSERTS)

#define DAWN_CHECK_CALLSITE_HELPER(file, func, line, condition)               \
    do {                                                                      \
        if (!(condition)) [[unlikely]] {                                      \
            if (std::is_constant_evaluated()) {                               \
                ::dawn::XXXXXXXXXX_CheckFailedInConsteval_XXXXXXXXXX();       \
            } else {                                                          \
                ::dawn::HandleAssertionFailure(file, func, line, #condition); \
                abort();                                                      \
            }                                                                 \
        }                                                                     \
    } while (DAWN_ASSERT_LOOP_CONDITION)

#define DAWN_ASSERT_CALLSITE_HELPER(file, func, line, condition)              \
    do {                                                                      \
        if (!(condition)) [[unlikely]] {                                      \
            if (std::is_constant_evaluated()) {                               \
                ::dawn::XXXXXXXXXX_CheckFailedInConsteval_XXXXXXXXXX();       \
            } else {                                                          \
                ::dawn::HandleAssertionFailure(file, func, line, #condition); \
            }                                                                 \
        }                                                                     \
    } while (DAWN_ASSERT_LOOP_CONDITION)

#define DAWN_RELEASE_ASSUME_CALLSITE_HELPER(file, func, line, condition) \
    DAWN_ASSERT_CALLSITE_HELPER(file, func, line, condition)

#else  // defined(DAWN_ENABLE_ASSERTS)

#define DAWN_CHECK_CALLSITE_HELPER(file, func, line, condition) \
    do {                                                        \
        if (!(condition)) [[unlikely]] {                        \
            abort();                                            \
        }                                                       \
    } while (DAWN_ASSERT_LOOP_CONDITION)

#define DAWN_ASSERT_CALLSITE_HELPER(file, func, line, condition) \
    do {                                                         \
        static_assert(sizeof(!!(condition)) == sizeof(bool));    \
    } while (DAWN_ASSERT_LOOP_CONDITION)

#if DAWN_COMPILER_IS(MSVC)
#define DAWN_RELEASE_ASSUME_CALLSITE_HELPER(file, func, line, condition) __assume(condition)
#elif DAWN_COMPILER_IS(CLANG) && __has_builtin(__builtin_assume)
#define DAWN_RELEASE_ASSUME_CALLSITE_HELPER(file, func, line, condition) \
    __builtin_assume(!!(condition))
#else  // DAWN_COMPILER_IS(*)
#define DAWN_RELEASE_ASSUME_CALLSITE_HELPER(file, func, line, condition) \
    DAWN_ASSERT_CALLSITE_HELPER(file, func, line, condition)
#endif  // DAWN_COMPILER_IS(*)

#endif  // defined(DAWN_ENABLE_ASSERTS)

// Equivalent to Chromium CHECK. In both debug and release, this asserts the condition is true.
#define DAWN_CHECK(condition) DAWN_CHECK_CALLSITE_HELPER(__FILE__, __func__, __LINE__, condition)
// Equivalent to Chromium DCHECK. In debug, this asserts the condition is true.
// In release, this does nothing (it doesn't __builtin_assume).
#define DAWN_ASSERT(condition) DAWN_ASSERT_CALLSITE_HELPER(__FILE__, __func__, __LINE__, condition)
// In release, this provides powerful __builtin_assume optimization hints to the compiler (without
// executing the condition expression). In debug, this is a DAWN_ASSERT.
#define DAWN_RELEASE_ASSUME(condition) \
    DAWN_RELEASE_ASSUME_CALLSITE_HELPER(__FILE__, __func__, __LINE__, condition)

// Check-false (similar to Chromium NOTREACHED).
// This will hard-abort in both debug and release.
#define DAWN_UNREACHABLE()                                                \
    do {                                                                  \
        DAWN_CHECK(DAWN_ASSERT_LOOP_CONDITION && "Unreachable code hit"); \
    } while (DAWN_ASSERT_LOOP_CONDITION)

namespace dawn {

[[noreturn]] void HandleAssertionFailure(const char* file,
                                         const char* function,
                                         int line,
                                         const char* condition);

// This non-consteval function is invalid to call in consteval. If it's called, the compiler will
// print "note: declared here" pointing to this function so the reader knows what's going on.
inline void XXXXXXXXXX_CheckFailedInConsteval_XXXXXXXXXX() {}

}  // namespace dawn

#endif  // SRC_UTILS_ASSERT_H_