Permit asm_const and asm_sym to reference outer generic params

rust-lang · May 7, 2022 · b1c6c06 · b1c6c06
1 parent d93b037
commit b1c6c06
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Showing 6 changed files with 60 additions and 47 deletions.
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
@@ -326,7 +326,7 @@ pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
         ItemKind::ForeignMod(ref foreign_module) => {
             walk_list!(visitor, visit_foreign_item, &foreign_module.items);
         }
-        ItemKind::GlobalAsm(ref asm) => walk_inline_asm(visitor, asm),
+        ItemKind::GlobalAsm(ref asm) => visitor.visit_inline_asm(asm),
         ItemKind::TyAlias(box TyAlias { ref generics, ref bounds, ref ty, .. }) => {
             visitor.visit_generics(generics);
             walk_list!(visitor, visit_param_bound, bounds, BoundKind::Bound);
@@ -897,7 +897,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
         }
         ExprKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
         ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
-        ExprKind::InlineAsm(ref asm) => walk_inline_asm(visitor, asm),
+        ExprKind::InlineAsm(ref asm) => visitor.visit_inline_asm(asm),
         ExprKind::Yield(ref optional_expression) => {
             walk_list!(visitor, visit_expr, optional_expression);
         }

diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
@@ -1171,6 +1171,7 @@ impl<'a> Resolver<'a> {
                         | AssocItemRibKind
                         | ModuleRibKind(..)
                         | MacroDefinition(..)
+                        | InlineAsmSymRibKind
                         | ForwardGenericParamBanRibKind => {
                             // Nothing to do. Continue.
                             continue;
@@ -1216,22 +1217,6 @@ impl<'a> Resolver<'a> {
                             }
                             return Res::Err;
                         }
-                        InlineAsmSymRibKind => {
-                            let features = self.session.features_untracked();
-                            if !features.generic_const_exprs {
-                                if let Some(span) = finalize {
-                                    self.report_error(
-                                        span,
-                                        ResolutionError::ParamInNonTrivialAnonConst {
-                                            name: rib_ident.name,
-                                            is_type: true,
-                                        },
-                                    );
-                                }
-                                return Res::Err;
-                            }
-                            continue;
-                        }
                     };
 
                     if let Some(span) = finalize {
@@ -1262,6 +1247,7 @@ impl<'a> Resolver<'a> {
                         | AssocItemRibKind
                         | ModuleRibKind(..)
                         | MacroDefinition(..)
+                        | InlineAsmSymRibKind
                         | ForwardGenericParamBanRibKind => continue,
 
                         ConstantItemRibKind(trivial, _) => {
@@ -1296,22 +1282,6 @@ impl<'a> Resolver<'a> {
                             }
                             return Res::Err;
                         }
-                        InlineAsmSymRibKind => {
-                            let features = self.session.features_untracked();
-                            if !features.generic_const_exprs {
-                                if let Some(span) = finalize {
-                                    self.report_error(
-                                        span,
-                                        ResolutionError::ParamInNonTrivialAnonConst {
-                                            name: rib_ident.name,
-                                            is_type: false,
-                                        },
-                                    );
-                                }
-                                return Res::Err;
-                            }
-                            continue;
-                        }
                     };
 
                     // This was an attempt to use a const parameter outside its scope.

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
@@ -918,6 +918,29 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
         self.diagnostic_metadata.current_where_predicate = previous_value;
     }
 
+    fn visit_inline_asm(&mut self, asm: &'ast InlineAsm) {
+        for (op, _) in &asm.operands {
+            match op {
+                InlineAsmOperand::In { expr, .. }
+                | InlineAsmOperand::Out { expr: Some(expr), .. }
+                | InlineAsmOperand::InOut { expr, .. } => self.visit_expr(expr),
+                InlineAsmOperand::Out { expr: None, .. } => {}
+                InlineAsmOperand::SplitInOut { in_expr, out_expr, .. } => {
+                    self.visit_expr(in_expr);
+                    if let Some(out_expr) = out_expr {
+                        self.visit_expr(out_expr);
+                    }
+                }
+                InlineAsmOperand::Const { anon_const, .. } => {
+                    // Although this is `DefKind::AnonConst`, it is allowed to reference outer
+                    // generic parameters like an inline const.
+                    self.resolve_inline_const(anon_const);
+                }
+                InlineAsmOperand::Sym { sym } => self.visit_inline_asm_sym(sym),
+            }
+        }
+    }
+
     fn visit_inline_asm_sym(&mut self, sym: &'ast InlineAsmSym) {
         // This is similar to the code for AnonConst.
         self.with_rib(ValueNS, InlineAsmSymRibKind, |this| {

diff --git a/src/test/ui/asm/generic-const.rs b/src/test/ui/asm/generic-const.rs
@@ -0,0 +1,30 @@
+// needs-asm-support
+// build-pass
+
+#![feature(asm_const, asm_sym)]
+
+use std::arch::asm;
+
+fn foofoo<const N: usize>() {}
+
+unsafe fn foo<const N: usize>() {
+    asm!("/* {0} */", const N);
+    asm!("/* {0} */", const N + 1);
+    asm!("/* {0} */", sym foofoo::<N>);
+}
+
+fn barbar<T>() {}
+
+unsafe fn bar<T>() {
+    asm!("/* {0} */", const std::mem::size_of::<T>());
+    asm!("/* {0} */", const std::mem::size_of::<(T, T)>());
+    asm!("/* {0} */", sym barbar::<T>);
+    asm!("/* {0} */", sym barbar::<(T, T)>);
+}
+
+fn main() {
+    unsafe {
+        foo::<0>();
+        bar::<usize>();
+    }
+}
diff --git a/src/test/ui/asm/type-check-1.rs b/src/test/ui/asm/type-check-1.rs
@@ -63,7 +63,6 @@ fn main() {
 
 unsafe fn generic<T>() {
     asm!("{}", sym generic::<T>);
-    //~^ generic parameters may not be used in const operations
 }
 
 // Const operands must be integers and must be constants.

diff --git a/src/test/ui/asm/type-check-1.stderr b/src/test/ui/asm/type-check-1.stderr
@@ -33,15 +33,6 @@ LL |         asm!("{}", sym x);
    |
    = help: `sym` operands must refer to either a function or a static
 
-error: generic parameters may not be used in const operations
-  --> $DIR/type-check-1.rs:65:30
-   |
-LL |     asm!("{}", sym generic::<T>);
-   |                              ^ cannot perform const operation using `T`
-   |
-   = note: type parameters may not be used in const expressions
-   = help: use `#![feature(generic_const_exprs)]` to allow generic const expressions
-
 error[E0308]: mismatched types
   --> $DIR/type-check-1.rs:55:26
    |
@@ -109,21 +100,21 @@ LL |         asm!("{}", inout(reg) v[..]);
    = note: all inline asm arguments must have a statically known size
 
 error[E0308]: mismatched types
-  --> $DIR/type-check-1.rs:74:25
+  --> $DIR/type-check-1.rs:73:25
    |
 LL | global_asm!("{}", const 0f32);
    |                         ^^^^ expected integer, found `f32`
 
 error[E0308]: mismatched types
-  --> $DIR/type-check-1.rs:76:25
+  --> $DIR/type-check-1.rs:75:25
    |
 LL | global_asm!("{}", const 0 as *mut u8);
    |                         ^^^^^^^^^^^^ expected integer, found *-ptr
    |
    = note:     expected type `{integer}`
            found raw pointer `*mut u8`
 
-error: aborting due to 15 previous errors
+error: aborting due to 14 previous errors
 
 Some errors have detailed explanations: E0277, E0308, E0435.
 For more information about an error, try `rustc --explain E0277`.