Add x86_64-fortanix-unknown-sgx target to libstd and dependencies

The files src/libstd/sys/sgx/*.rs are mostly copied/adapted from
the wasm target.

This also updates the dlmalloc submodule to the very latest version.

Author: Jethro Beekman

.gitmodules

@@ -61,10 +61,12 @@
 	path = src/tools/clang
 	url = https://github.com/rust-lang-nursery/clang.git
 	branch = rust-release-80-v2
-
 [submodule "src/doc/rustc-guide"]
 	path = src/doc/rustc-guide
 	url = https://github.com/rust-lang/rustc-guide.git
 [submodule "src/doc/edition-guide"]
 	path = src/doc/edition-guide
 	url = https://github.com/rust-lang-nursery/edition-guide
+[submodule "src/rust-sgx"]
+	path = src/rust-sgx
+	url = https://github.com/fortanix/rust-sgx

Cargo.lock

@@ -797,6 +797,14 @@ name = "foreign-types-shared"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "fortanix-sgx-abi"
+version = "0.0.0"
+dependencies = [
+ "compiler_builtins 0.0.0",
+ "core 0.0.0",
+]
+
 [[package]]
 name = "fs2"
 version = "0.4.3"
@@ -2773,6 +2781,7 @@ dependencies = [
  "compiler_builtins 0.0.0",
  "core 0.0.0",
  "dlmalloc 0.0.0",
+ "fortanix-sgx-abi 0.0.0",
  "libc 0.0.0",
  "panic_abort 0.0.0",
  "panic_unwind 0.0.0",

src/bootstrap/dist.rs

@@ -874,6 +874,7 @@ impl Step for Src {
             "src/rustc/compiler_builtins_shim",
             "src/rustc/libc_shim",
             "src/rustc/dlmalloc_shim",
+            "src/rustc/fortanix-sgx-abi_shim",
             "src/libtest",
             "src/libterm",
             "src/libprofiler_builtins",

src/dlmalloc

@@ -66,6 +66,12 @@ pub unsafe extern fn __rust_start_panic(_payload: usize) -> u32 {
     unsafe fn abort() -> ! {
         core::intrinsics::abort();
     }
+
+    #[cfg(target_env="sgx")]
+    unsafe fn abort() -> ! {
+        extern "C" { pub fn panic_exit() -> !; }
+        panic_exit();
+    }
 }
 
 // This... is a bit of an oddity. The tl;dr; is that this is required to link

src/liblibc

@@ -62,7 +62,7 @@ cfg_if! {
     if #[cfg(target_os = "emscripten")] {
         #[path = "emcc.rs"]
         mod imp;
-    } else if #[cfg(target_arch = "wasm32")] {
+    } else if #[cfg(any(target_arch = "wasm32", target_env = "sgx"))] {
         #[path = "dummy.rs"]
         mod imp;
     } else if #[cfg(all(target_env = "msvc", target_arch = "aarch64"))] {

src/libpanic_abort/lib.rs

@@ -35,9 +35,12 @@ rustc_lsan = { path = "../librustc_lsan" }
 rustc_msan = { path = "../librustc_msan" }
 rustc_tsan = { path = "../librustc_tsan" }
 
-[target.'cfg(all(target_arch = "wasm32", not(target_os = "emscripten")))'.dependencies]
+[target.'cfg(any(all(target_arch = "wasm32", not(target_os = "emscripten")), target_env = "sgx"))'.dependencies]
 dlmalloc = { path = '../rustc/dlmalloc_shim' }
 
+[target.x86_64-fortanix-unknown-sgx.dependencies]
+fortanix-sgx-abi = { path = "../rustc/fortanix-sgx-abi_shim" }
+
 [build-dependencies]
 cc = "1.0"
 build_helper = { path = "../build_helper" }

src/libpanic_unwind/lib.rs

@@ -184,7 +184,7 @@ pub enum ErrorKind {
 }
 
 impl ErrorKind {
-    fn as_str(&self) -> &'static str {
+    pub(crate) fn as_str(&self) -> &'static str {
         match *self {
             ErrorKind::NotFound => "entity not found",
             ErrorKind::PermissionDenied => "permission denied",

src/libstd/Cargo.toml

@@ -312,6 +312,7 @@
 #![feature(non_exhaustive)]
 #![feature(alloc_layout_extra)]
 #![feature(maybe_uninit)]
+#![cfg_attr(target_env = "sgx", feature(global_asm, range_contains))]
 
 #![default_lib_allocator]
 
@@ -354,6 +355,12 @@ extern crate unwind;
 // testing gives test-std access to real-std lang items and globals. See #2912
 #[cfg(test)] extern crate std as realstd;
 
+#[cfg(target_env = "sgx")]
+#[macro_use]
+#[allow(unused_imports)] // FIXME: without `#[macro_use]`, get error: “cannot
+                         // determine resolution for the macro `usercalls_asm`”
+extern crate fortanix_sgx_abi;
+
 // The standard macros that are not built-in to the compiler.
 #[macro_use]
 mod macros;

src/libstd/io/error.rs

@@ -48,6 +48,9 @@ cfg_if! {
     } else if #[cfg(target_arch = "wasm32")] {
         mod wasm;
         pub use self::wasm::*;
+    } else if #[cfg(target_env = "sgx")] {
+        mod sgx;
+        pub use self::sgx::*;
     } else {
         compile_error!("libstd doesn't compile for this platform yet");
     }