Rollup merge of rust-lang#57803 - jethrogb:jb/sgx-unwind-version, r=alexcrichton

Several changes to libunwind for SGX target

Two fixes:
* rust-lang#34978 bites again!
* __rust_alloc are actually private symbols. Add new public versions. Also, these ones are `extern "C"`.

Upstream changes (fortanix/llvm-project#2, fortanix/llvm-project#3):
* b7357de Avoid too new relocation types being emitted
* 0feefe5 Use new symbol names to call Rust allocator

Fixes fortanix/rust-sgx#65

Author: Centril

src/ci/docker/dist-various-2/Dockerfile

@@ -32,7 +32,7 @@ RUN /tmp/build-solaris-toolchain.sh sparcv9 sparcv9 solaris-sparc
 COPY dist-various-2/build-x86_64-fortanix-unknown-sgx-toolchain.sh /tmp/
 # We pass the commit id of the port of LLVM's libunwind to the build script.
 # Any update to the commit id here, should cause the container image to be re-built from this point on.
-RUN /tmp/build-x86_64-fortanix-unknown-sgx-toolchain.sh "bbe23902411be88d7388f381becefadd6e3ef819"
+RUN /tmp/build-x86_64-fortanix-unknown-sgx-toolchain.sh "13fad13f8ea83a8da58d04a5faa45943151b3398"
 
 COPY scripts/sccache.sh /scripts/
 RUN sh /scripts/sccache.sh

src/libstd/sys/sgx/rwlock.rs

@@ -1,3 +1,4 @@
+use alloc::{self, Layout};
 use num::NonZeroUsize;
 use slice;
 use str;
@@ -147,6 +148,7 @@ impl RWLock {
         self.__write_unlock(rguard, wguard);
     }
 
+    // only used by __rust_rwlock_unlock below
     #[inline]
     unsafe fn unlock(&self) {
         let rguard = self.readers.lock();
@@ -164,6 +166,7 @@ impl RWLock {
 
 const EINVAL: i32 = 22;
 
+// used by libunwind port
 #[no_mangle]
 pub unsafe extern "C" fn __rust_rwlock_rdlock(p: *mut RWLock) -> i32 {
     if p.is_null() {
@@ -190,6 +193,8 @@ pub unsafe extern "C" fn __rust_rwlock_unlock(p: *mut RWLock) -> i32 {
     return 0;
 }
 
+// the following functions are also used by the libunwind port. They're
+// included here to make sure parallel codegen and LTO don't mess things up.
 #[no_mangle]
 pub unsafe extern "C" fn __rust_print_err(m: *mut u8, s: i32) {
     if s < 0 {
@@ -206,6 +211,16 @@ pub unsafe extern "C" fn __rust_abort() {
     ::sys::abort_internal();
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn __rust_c_alloc(size: usize, align: usize) -> *mut u8 {
+    alloc::alloc(Layout::from_size_align_unchecked(size, align))
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn __rust_c_dealloc(ptr: *mut u8, size: usize, align: usize) {
+    alloc::dealloc(ptr, Layout::from_size_align_unchecked(size, align))
+}
+
 #[cfg(test)]
 mod tests {