Auto merge of rust-lang#79594 - vn-ki:const-eval-intrinsic, r=oli-obk

add const_allocate intrinsic

r? `@oli-obk`

fixes rust-lang#75390

Author: bors

core/src/intrinsics.rs

@@ -1732,6 +1732,11 @@ extern "rust-intrinsic" {
     /// See documentation of `<*const T>::guaranteed_ne` for details.
     #[rustc_const_unstable(feature = "const_raw_ptr_comparison", issue = "53020")]
     pub fn ptr_guaranteed_ne<T>(ptr: *const T, other: *const T) -> bool;
+
+    /// Allocate at compile time. Should not be called at runtime.
+    #[rustc_const_unstable(feature = "const_heap", issue = "79597")]
+    #[cfg(not(bootstrap))]
+    pub fn const_allocate(size: usize, align: usize) -> *mut u8;
 }
 
 // Some functions are defined here because they accidentally got made

core/src/lib.rs

@@ -68,6 +68,7 @@
 #![feature(arbitrary_self_types)]
 #![feature(asm)]
 #![feature(cfg_target_has_atomic)]
+#![cfg_attr(not(bootstrap), feature(const_heap))]
 #![feature(const_alloc_layout)]
 #![feature(const_discriminant)]
 #![feature(const_cell_into_inner)]