Rollup merge of rust-lang#139795 - jethrogb:jb/sgx-linkage-comments, r=joboet

Clarify why SGX code specifies linkage/symbol names for certain statics

Specifying linkage/symbol name is solely to ensure a single instance between the `std` crate and its unit tests.

Also update the symbol names as items have moved around a bit. The actual name isn't that important, it just needs to be unique. But for debugging it can be useful for it to point to the right place.

Author: ChrisDenton

std/src/sys/alloc/sgx.rs

@@ -10,8 +10,10 @@ use crate::sys::pal::waitqueue::SpinMutex;
 // The current allocator here is the `dlmalloc` crate which we've got included
 // in the rust-lang/rust repository as a submodule. The crate is a port of
 // dlmalloc.c from C to Rust.
+//
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
 #[cfg_attr(test, linkage = "available_externally")]
-#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx5alloc8DLMALLOCE")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys5alloc3sgx8DLMALLOCE")]
 static DLMALLOC: SpinMutex<dlmalloc::Dlmalloc<Sgx>> =
     SpinMutex::new(dlmalloc::Dlmalloc::new_with_allocator(Sgx {}));
 

std/src/sys/args/sgx.rs

@@ -8,6 +8,7 @@ use crate::sys::pal::abi::usercalls::raw::ByteBuffer;
 use crate::sys_common::FromInner;
 use crate::{fmt, slice};
 
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
 #[cfg_attr(test, linkage = "available_externally")]
 #[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx4args4ARGSE")]
 static ARGS: AtomicUsize = AtomicUsize::new(0);

std/src/sys/pal/sgx/abi/tls/mod.rs

@@ -11,15 +11,17 @@ const USIZE_BITS: usize = 64;
 const TLS_KEYS: usize = 128; // Same as POSIX minimum
 const TLS_KEYS_BITSET_SIZE: usize = (TLS_KEYS + (USIZE_BITS - 1)) / USIZE_BITS;
 
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
 #[cfg_attr(test, linkage = "available_externally")]
-#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_KEY_IN_USEE")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx3abi3tls14TLS_KEY_IN_USEE")]
 static TLS_KEY_IN_USE: SyncBitset = SYNC_BITSET_INIT;
 macro_rules! dup {
     ((* $($exp:tt)*) $($val:tt)*) => (dup!( ($($exp)*) $($val)* $($val)* ));
     (() $($val:tt)*) => ([$($val),*])
 }
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
 #[cfg_attr(test, linkage = "available_externally")]
-#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx3abi3tls14TLS_DESTRUCTORE")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx3abi3tls14TLS_DESTRUCTORE")]
 static TLS_DESTRUCTOR: [AtomicUsize; TLS_KEYS] = dup!((* * * * * * *) (AtomicUsize::new(0)));
 
 unsafe extern "C" {

std/src/sys/pal/sgx/os.rs

@@ -73,11 +73,13 @@ pub fn current_exe() -> io::Result<PathBuf> {
     unsupported()
 }
 
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
 #[cfg_attr(test, linkage = "available_externally")]
-#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx2os3ENVE")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx2os3ENVE")]
 static ENV: AtomicUsize = AtomicUsize::new(0);
+// Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
 #[cfg_attr(test, linkage = "available_externally")]
-#[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx2os8ENV_INITE")]
+#[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx2os8ENV_INITE")]
 static ENV_INIT: Once = Once::new();
 type EnvStore = Mutex<HashMap<OsString, OsString>>;
 

std/src/sys/pal/sgx/thread.rs

@@ -45,8 +45,9 @@ mod task_queue {
         }
     }
 
+    // Specifying linkage/symbol name is solely to ensure a single instance between this crate and its unit tests
     #[cfg_attr(test, linkage = "available_externally")]
-    #[unsafe(export_name = "_ZN16__rust_internals3std3sys3sgx6thread10TASK_QUEUEE")]
+    #[unsafe(export_name = "_ZN16__rust_internals3std3sys3pal3sgx6thread10TASK_QUEUEE")]
     static TASK_QUEUE: Mutex<Vec<Task>> = Mutex::new(Vec::new());
 
     pub(super) fn lock() -> MutexGuard<'static, Vec<Task>> {