[libc++] Disable CFI in __libcpp_allocate (#124805)

ldionne · web-flow · commit 9f660625bee6 · 2025-01-28T15:43:21.000-05:00
Since we're casting uninitialized memory, we must disable CFI checks.
diff --git a/libcxx/include/__new/allocate.h b/libcxx/include/__new/allocate.h
@@ -50,7 +50,8 @@ _LIBCPP_HIDE_FROM_ABI void __libcpp_operator_delete(_Args... __args) _NOEXCEPT {
 }
 
 template <class _Tp>
-inline _LIBCPP_HIDE_FROM_ABI _Tp* __libcpp_allocate(__element_count __n, size_t __align = _LIBCPP_ALIGNOF(_Tp)) {
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI _Tp*
+__libcpp_allocate(__element_count __n, size_t __align = _LIBCPP_ALIGNOF(_Tp)) {
   size_t __size = static_cast<size_t>(__n) * sizeof(_Tp);
 #if _LIBCPP_HAS_ALIGNED_ALLOCATION
   if (__is_overaligned_for_new(__align)) {

Original file line number	Diff line number	Diff line change
`@@ -50,7 +50,8 @@ _LIBCPP_HIDE_FROM_ABI void __libcpp_operator_delete(_Args... __args) _NOEXCEPT {`
`50`	`50`	`}`
`51`	`51`
`52`	`52`	`template <class _Tp>`
`53`		`-inline _LIBCPP_HIDE_FROM_ABI _Tp* __libcpp_allocate(__element_count __n, size_t __align = _LIBCPP_ALIGNOF(_Tp)) {`
	`53`	`+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_NO_CFI _Tp*`
	`54`	`+__libcpp_allocate(__element_count __n, size_t __align = _LIBCPP_ALIGNOF(_Tp)) {`
`54`	`55`	`size_t __size = static_cast<size_t>(__n) * sizeof(_Tp);`
`55`	`56`	`#if _LIBCPP_HAS_ALIGNED_ALLOCATION`
`56`	`57`	`if (__is_overaligned_for_new(__align)) {`