Add cfg(target_has_atomic_equal_alignment).

This is needed for Atomic::from_mut.

diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index fc122db8ac1b1f2502c2079bdf10e6c3fe53ea17..8b7fd59cd874ae57c665d559af0de011bad64126 100644 (file)
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -26,6 +26,11 @@ macro_rules! cfg_fn {
     (sym::target_thread_local, sym::cfg_target_thread_local, cfg_fn!(cfg_target_thread_local)),
     (sym::target_has_atomic, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
     (sym::target_has_atomic_load_store, sym::cfg_target_has_atomic, cfg_fn!(cfg_target_has_atomic)),
+    (
+        sym::target_has_atomic_equal_alignment,
+        sym::cfg_target_has_atomic,
+        cfg_fn!(cfg_target_has_atomic),
+    ),
     (sym::sanitize, sym::cfg_sanitize, cfg_fn!(cfg_sanitize)),
     (sym::version, sym::cfg_version, cfg_fn!(cfg_version)),
 ];

diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index 8d004675d7f4dd69aaa4196e4083fb80821e3150..09e5948cdd750b37b8f7592be8dd19a983b5c099 100644 (file)
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -12,6 +12,7 @@
 use rustc_data_structures::impl_stable_hash_via_hash;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 
+use rustc_target::abi::{Align, TargetDataLayout};
 use rustc_target::spec::{Target, TargetTriple};
 
 use crate::parse::CrateConfig;
@@ -748,6 +749,7 @@ pub fn default_configuration(sess: &Session) -> CrateConfig {
     let min_atomic_width = sess.target.target.min_atomic_width();
     let max_atomic_width = sess.target.target.max_atomic_width();
     let atomic_cas = sess.target.target.options.atomic_cas;
+    let layout = TargetDataLayout::parse(&sess.target.target).unwrap();
 
     let mut ret = FxHashSet::default();
     ret.reserve(6); // the minimum number of insertions
@@ -769,18 +771,27 @@ pub fn default_configuration(sess: &Session) -> CrateConfig {
     if sess.target.target.options.has_elf_tls {
         ret.insert((sym::target_thread_local, None));
     }
-    for &i in &[8, 16, 32, 64, 128] {
+    for &(i, align) in &[
+        (8, layout.i8_align.abi),
+        (16, layout.i16_align.abi),
+        (32, layout.i32_align.abi),
+        (64, layout.i64_align.abi),
+        (128, layout.i128_align.abi),
+    ] {
         if i >= min_atomic_width && i <= max_atomic_width {
-            let mut insert_atomic = |s| {
+            let mut insert_atomic = |s, align: Align| {
                 ret.insert((sym::target_has_atomic_load_store, Some(Symbol::intern(s))));
                 if atomic_cas {
                     ret.insert((sym::target_has_atomic, Some(Symbol::intern(s))));
                 }
+                if align.bits() == i {
+                    ret.insert((sym::target_has_atomic_equal_alignment, Some(Symbol::intern(s))));
+                }
             };
             let s = i.to_string();
-            insert_atomic(&s);
+            insert_atomic(&s, align);
             if &s == wordsz {
-                insert_atomic("ptr");
+                insert_atomic("ptr", layout.pointer_align.abi);
             }
         }
     }

diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 6085eedf23694404fbf1a12ff1fb378a221c7eb7..60688d26d4ce0dbd4c1f9f4638ec3ad2ced0717a 100644 (file)
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1071,6 +1071,7 @@
         target_feature,
         target_feature_11,
         target_has_atomic,
+        target_has_atomic_equal_alignment,
         target_has_atomic_load_store,
         target_os,
         target_pointer_width,