libcxxabi/src/stdlib_new_delete.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "__cxxabi_config.h"
#include <__memory/aligned_alloc.h>
#include <cstdlib>
#include <new>

// Perform a few sanity checks on libc++ and libc++abi macros to ensure that
// the code below can be an exact copy of the code in libcxx/src/new.cpp.
#if !defined(_THROW_BAD_ALLOC)
#  error The _THROW_BAD_ALLOC macro should be already defined by libc++
#endif

#ifndef _LIBCPP_WEAK
#  error The _LIBCPP_WEAK macro should be already defined by libc++
#endif

#if defined(_LIBCXXABI_NO_EXCEPTIONS) != defined(_LIBCPP_HAS_NO_EXCEPTIONS)
#  error libc++ and libc++abi seem to disagree on whether exceptions are enabled
#endif

// ------------------ BEGIN COPY ------------------
// Implement all new and delete operators as weak definitions
// in this shared library, so that they can be overridden by programs
// that define non-weak copies of the functions.

static void* operator_new_impl(std::size_t size) noexcept {
  if (size == 0)
    size = 1;
  void* p;
  while ((p = std::malloc(size)) == nullptr) {
    // If malloc fails and there is a new_handler,
    // call it to try free up memory.
    std::new_handler nh = std::get_new_handler();
    if (nh)
      nh();
    else
      break;
  }
  return p;
}

_LIBCPP_WEAK
void* operator new(std::size_t size) _THROW_BAD_ALLOC {
  void* p = operator_new_impl(size);
#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  if (p == nullptr)
    throw std::bad_alloc();
#endif
  return p;
}

_LIBCPP_WEAK
void* operator new(size_t size, const std::nothrow_t&) noexcept {
  void* p = nullptr;
#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  try {
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
    p = ::operator new(size);
#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  } catch (...) {
  }
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
  return p;
}

_LIBCPP_WEAK
void* operator new[](size_t size) _THROW_BAD_ALLOC { return ::operator new(size); }

_LIBCPP_WEAK
void* operator new[](size_t size, const std::nothrow_t&) noexcept {
  void* p = nullptr;
#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  try {
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
    p = ::operator new[](size);
#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  } catch (...) {
  }
#endif // _LIBCPP_HAS_NO_EXCEPTIONS
  return p;
}

_LIBCPP_WEAK
void operator delete(void* ptr) noexcept { std::free(ptr); }

_LIBCPP_WEAK
void operator delete(void* ptr, const std::nothrow_t&) noexcept { ::operator delete(ptr); }

_LIBCPP_WEAK
void operator delete(void* ptr, size_t) noexcept { ::operator delete(ptr); }

_LIBCPP_WEAK
void operator delete[](void* ptr) noexcept { ::operator delete(ptr); }

_LIBCPP_WEAK
void operator delete[](void* ptr, const std::nothrow_t&) noexcept { ::operator delete[](ptr); }

_LIBCPP_WEAK
void operator delete[](void* ptr, size_t) noexcept { ::operator delete[](ptr); }

#if !defined(_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION)

static void* operator_new_aligned_impl(std::size_t size, std::align_val_t alignment) noexcept {
  if (size == 0)
    size = 1;
  if (static_cast<size_t>(alignment) < sizeof(void*))
    alignment = std::align_val_t(sizeof(void*));

  // Try allocating memory. If allocation fails and there is a new_handler,
  // call it to try free up memory, and try again until it succeeds, or until
  // the new_handler decides to terminate.
  void* p;
  while ((p = std::__libcpp_aligned_alloc(static_cast<std::size_t>(alignment), size)) == nullptr) {
    std::new_handler nh = std::get_new_handler();
    if (nh)
      nh();
    else
      break;
  }
  return p;
}

_LIBCPP_WEAK
void* operator new(std::size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC {
  void* p = operator_new_aligned_impl(size, alignment);
#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  if (p == nullptr)
    throw std::bad_alloc();
#  endif
  return p;
}

_LIBCPP_WEAK
void* operator new(size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
  void* p = nullptr;
#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  try {
#  endif // _LIBCPP_HAS_NO_EXCEPTIONS
    p = ::operator new(size, alignment);
#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  } catch (...) {
  }
#  endif // _LIBCPP_HAS_NO_EXCEPTIONS
  return p;
}

_LIBCPP_WEAK
void* operator new[](size_t size, std::align_val_t alignment) _THROW_BAD_ALLOC {
  return ::operator new(size, alignment);
}

_LIBCPP_WEAK
void* operator new[](size_t size, std::align_val_t alignment, const std::nothrow_t&) noexcept {
  void* p = nullptr;
#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  try {
#  endif // _LIBCPP_HAS_NO_EXCEPTIONS
    p = ::operator new[](size, alignment);
#  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  } catch (...) {
  }
#  endif // _LIBCPP_HAS_NO_EXCEPTIONS
  return p;
}

_LIBCPP_WEAK
void operator delete(void* ptr, std::align_val_t) noexcept { std::__libcpp_aligned_free(ptr); }

_LIBCPP_WEAK
void operator delete(void* ptr, std::align_val_t alignment, const std::nothrow_t&) noexcept {
  ::operator delete(ptr, alignment);
}

_LIBCPP_WEAK
void operator delete(void* ptr, size_t, std::align_val_t alignment) noexcept { ::operator delete(ptr, alignment); }

_LIBCPP_WEAK
void operator delete[](void* ptr, std::align_val_t alignment) noexcept { ::operator delete(ptr, alignment); }

_LIBCPP_WEAK
void operator delete[](void* ptr, std::align_val_t alignment, const std::nothrow_t&) noexcept {
  ::operator delete[](ptr, alignment);
}

_LIBCPP_WEAK
void operator delete[](void* ptr, size_t, std::align_val_t alignment) noexcept { ::operator delete[](ptr, alignment); }

#endif // !_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION
// ------------------ END COPY ------------------