Implement optimize(none)

Author: clubby789

compiler/rustc_attr/src/builtin.rs

@@ -55,8 +55,11 @@ pub enum InstructionSetAttr {
 
 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum OptimizeAttr {
+    /// `#[optimize(none)]`
     None,
+    /// `#[optimize(speed)]`
     Speed,
+    /// `#[optimize(size)]`
     Size,
 }
 

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -336,14 +336,17 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     let mut to_add = SmallVec::<[_; 16]>::new();
 
     match codegen_fn_attrs.optimize {
-        OptimizeAttr::None => {
+        None => {
             to_add.extend(default_optimisation_attrs(cx));
         }
-        OptimizeAttr::Size => {
+        Some(OptimizeAttr::None) => {
+            to_add.push(llvm::AttributeKind::OptimizeNone.create_attr(cx.llcx));
+        }
+        Some(OptimizeAttr::Size) => {
             to_add.push(llvm::AttributeKind::MinSize.create_attr(cx.llcx));
             to_add.push(llvm::AttributeKind::OptimizeForSize.create_attr(cx.llcx));
         }
-        OptimizeAttr::Speed => {}
+        Some(OptimizeAttr::Speed) => {}
     }
 
     let inline =

compiler/rustc_codegen_ssa/src/base.rs

@@ -1024,8 +1024,8 @@ pub fn provide(providers: &mut Providers) {
         let any_for_speed = defids.items().any(|id| {
             let CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
             match optimize {
-                attr::OptimizeAttr::None | attr::OptimizeAttr::Size => false,
-                attr::OptimizeAttr::Speed => true,
+                None | Some(attr::OptimizeAttr::None | attr::OptimizeAttr::Size) => false,
+                Some(attr::OptimizeAttr::Speed) => true,
             }
         });
 

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -559,7 +559,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
         }
     });
 
-    codegen_fn_attrs.optimize = attrs.iter().fold(OptimizeAttr::None, |ia, attr| {
+    codegen_fn_attrs.optimize = attrs.iter().fold(None, |ia, attr| {
         if !attr.has_name(sym::optimize) {
             return ia;
         }
@@ -573,14 +573,16 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                 inline_span = Some(attr.span);
                 if items.len() != 1 {
                     err(attr.span, "expected one argument");
-                    OptimizeAttr::None
+                    None
                 } else if list_contains_name(items, sym::size) {
-                    OptimizeAttr::Size
+                    Some(OptimizeAttr::Size)
                 } else if list_contains_name(items, sym::speed) {
-                    OptimizeAttr::Speed
+                    Some(OptimizeAttr::Speed)
+                } else if list_contains_name(items, sym::none) {
+                    Some(OptimizeAttr::None)
                 } else {
                     err(items[0].span(), "invalid argument");
-                    OptimizeAttr::None
+                    None
                 }
             }
             Some(MetaItemKind::NameValue(_)) => ia,

compiler/rustc_middle/src/middle/codegen_fn_attrs.rs

@@ -11,8 +11,8 @@ pub struct CodegenFnAttrs {
     pub flags: CodegenFnAttrFlags,
     /// Parsed representation of the `#[inline]` attribute
     pub inline: InlineAttr,
-    /// Parsed representation of the `#[optimize]` attribute
-    pub optimize: OptimizeAttr,
+    /// Parsed representation of the `#[optimize]` attribute if present
+    pub optimize: Option<OptimizeAttr>,
     /// The `#[export_name = "..."]` attribute, indicating a custom symbol a
     /// function should be exported under
     pub export_name: Option<Symbol>,
@@ -137,7 +137,7 @@ impl CodegenFnAttrs {
         CodegenFnAttrs {
             flags: CodegenFnAttrFlags::empty(),
             inline: InlineAttr::None,
-            optimize: OptimizeAttr::None,
+            optimize: None,
             export_name: None,
             link_name: None,
             link_ordinal: None,

tests/ui/feature-gates/feature-gate-optimize_attribute.rs

@@ -10,6 +10,9 @@ fn size() {}
 #[optimize(speed)] //~ ERROR the `#[optimize]` attribute is an experimental feature
 fn speed() {}
 
+#[optimize(none)] //~ ERROR the `#[optimize]` attribute is an experimental feature
+fn none() {}
+
 #[optimize(banana)]
 //~^ ERROR the `#[optimize]` attribute is an experimental feature
 //~| ERROR E0722

tests/ui/feature-gates/feature-gate-optimize_attribute.stderr

@@ -41,6 +41,16 @@ LL | #[optimize(speed)]
 error[E0658]: the `#[optimize]` attribute is an experimental feature
   --> $DIR/feature-gate-optimize_attribute.rs:13:1
    |
+LL | #[optimize(none)]
+   | ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #54882 <https://github.com/rust-lang/rust/issues/54882> for more information
+   = help: add `#![feature(optimize_attribute)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: the `#[optimize]` attribute is an experimental feature
+  --> $DIR/feature-gate-optimize_attribute.rs:16:1
+   |
 LL | #[optimize(banana)]
    | ^^^^^^^^^^^^^^^^^^^
    |
@@ -49,12 +59,12 @@ LL | #[optimize(banana)]
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
 error[E0722]: invalid argument
-  --> $DIR/feature-gate-optimize_attribute.rs:13:12
+  --> $DIR/feature-gate-optimize_attribute.rs:16:12
    |
 LL | #[optimize(banana)]
    |            ^^^^^^
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
 Some errors have detailed explanations: E0658, E0722.
 For more information about an error, try `rustc --explain E0658`.