Add asm label support to AST and HIR

nbdd0121 · nbdd0121 · commit 30ba978ca021 · 2023-12-27T23:25:00.000Z
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
@@ -2272,6 +2272,9 @@ pub enum InlineAsmOperand {
     Sym {
         sym: InlineAsmSym,
     },
+    Label {
+        block: P<Block>,
+    },
 }
 
 impl InlineAsmOperand {
@@ -2281,7 +2284,7 @@ impl InlineAsmOperand {
             | Self::Out { reg, .. }
             | Self::InOut { reg, .. }
             | Self::SplitInOut { reg, .. } => Some(reg),
-            Self::Const { .. } | Self::Sym { .. } => None,
+            Self::Const { .. } | Self::Sym { .. } | Self::Label { .. } => None,
         }
     }
 }
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
@@ -1308,6 +1308,7 @@ pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {
             }
             InlineAsmOperand::Const { anon_const } => vis.visit_anon_const(anon_const),
             InlineAsmOperand::Sym { sym } => vis.visit_inline_asm_sym(sym),
+            InlineAsmOperand::Label { block } => vis.visit_block(block),
         }
     }
 }
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
@@ -763,6 +763,7 @@ pub fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm)
             }
             InlineAsmOperand::Const { anon_const, .. } => visitor.visit_anon_const(anon_const),
             InlineAsmOperand::Sym { sym } => visitor.visit_inline_asm_sym(sym),
+            InlineAsmOperand::Label { block } => visitor.visit_block(block),
         }
     }
 }
diff --git a/compiler/rustc_ast_lowering/messages.ftl b/compiler/rustc_ast_lowering/messages.ftl
@@ -81,6 +81,9 @@ ast_lowering_invalid_abi_suggestion = did you mean
 ast_lowering_invalid_asm_template_modifier_const =
     asm template modifiers are not allowed for `const` arguments
 
+ast_lowering_invalid_asm_template_modifier_label =
+    asm template modifiers are not allowed for `label` arguments
+
 ast_lowering_invalid_asm_template_modifier_reg_class =
     invalid asm template modifier for this register class
 
diff --git a/compiler/rustc_ast_lowering/src/asm.rs b/compiler/rustc_ast_lowering/src/asm.rs
@@ -3,9 +3,9 @@ use crate::{ImplTraitContext, ImplTraitPosition, ParamMode, ResolverAstLoweringE
 use super::errors::{
     AbiSpecifiedMultipleTimes, AttSyntaxOnlyX86, ClobberAbiNotSupported,
     InlineAsmUnsupportedTarget, InvalidAbiClobberAbi, InvalidAsmTemplateModifierConst,
-    InvalidAsmTemplateModifierRegClass, InvalidAsmTemplateModifierRegClassSub,
-    InvalidAsmTemplateModifierSym, InvalidRegister, InvalidRegisterClass, RegisterClassOnlyClobber,
-    RegisterConflict,
+    InvalidAsmTemplateModifierLabel, InvalidAsmTemplateModifierRegClass,
+    InvalidAsmTemplateModifierRegClassSub, InvalidAsmTemplateModifierSym, InvalidRegister,
+    InvalidRegisterClass, RegisterClassOnlyClobber, RegisterConflict,
 };
 use super::LoweringContext;
 
@@ -241,6 +241,18 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             }
                         }
                     }
+                    InlineAsmOperand::Label { block } => {
+                        if !self.tcx.features().asm_goto {
+                            feature_err(
+                                &sess.parse_sess,
+                                sym::asm_goto,
+                                *op_sp,
+                                "label operands for inline assembly are unstable",
+                            )
+                            .emit();
+                        }
+                        hir::InlineAsmOperand::Label { block: self.lower_block(block, false) }
+                    }
                 };
                 (op, self.lower_span(*op_sp))
             })
@@ -300,6 +312,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                             op_span: op_sp,
                         });
                     }
+                    hir::InlineAsmOperand::Label { .. } => {
+                        self.dcx().emit_err(InvalidAsmTemplateModifierLabel {
+                            placeholder_span,
+                            op_span: op_sp,
+                        });
+                    }
                 }
             }
         }
@@ -339,7 +357,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
                         hir::InlineAsmOperand::Const { .. }
                         | hir::InlineAsmOperand::SymFn { .. }
-                        | hir::InlineAsmOperand::SymStatic { .. } => {
+                        | hir::InlineAsmOperand::SymStatic { .. }
+                        | hir::InlineAsmOperand::Label { .. } => {
                             unreachable!("{op:?} is not a register operand");
                         }
                     };
diff --git a/compiler/rustc_ast_lowering/src/errors.rs b/compiler/rustc_ast_lowering/src/errors.rs
@@ -267,6 +267,16 @@ pub struct InvalidAsmTemplateModifierSym {
     pub op_span: Span,
 }
 
+#[derive(Diagnostic, Clone, Copy)]
+#[diag(ast_lowering_invalid_asm_template_modifier_label)]
+pub struct InvalidAsmTemplateModifierLabel {
+    #[primary_span]
+    #[label(ast_lowering_template_modifier)]
+    pub placeholder_span: Span,
+    #[label(ast_lowering_argument)]
+    pub op_span: Span,
+}
+
 #[derive(Diagnostic, Clone, Copy)]
 #[diag(ast_lowering_register_class_only_clobber)]
 pub struct RegisterClassOnlyClobber {
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -1298,6 +1298,10 @@ impl<'a> State<'a> {
                             s.print_path(&sym.path, true, 0);
                         }
                     }
+                    InlineAsmOperand::Label { block } => {
+                        s.head("label");
+                        s.print_block(block);
+                    }
                 }
             }
             AsmArg::ClobberAbi(abi) => {
diff --git a/compiler/rustc_builtin_macros/src/asm.rs b/compiler/rustc_builtin_macros/src/asm.rs
@@ -166,6 +166,9 @@ pub fn parse_asm_args<'a>(
                 path: path.clone(),
             };
             ast::InlineAsmOperand::Sym { sym }
+        } else if p.eat_keyword(sym::label) {
+            let block = p.parse_block()?;
+            ast::InlineAsmOperand::Label { block }
         } else if allow_templates {
             let template = p.parse_expr()?;
             // If it can't possibly expand to a string, provide diagnostics here to include other
diff --git a/compiler/rustc_codegen_ssa/src/mono_item.rs b/compiler/rustc_codegen_ssa/src/mono_item.rs
@@ -76,7 +76,8 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
                             hir::InlineAsmOperand::In { .. }
                             | hir::InlineAsmOperand::Out { .. }
                             | hir::InlineAsmOperand::InOut { .. }
-                            | hir::InlineAsmOperand::SplitInOut { .. } => {
+                            | hir::InlineAsmOperand::SplitInOut { .. }
+                            | hir::InlineAsmOperand::Label { .. } => {
                                 span_bug!(*op_sp, "invalid operand type for global_asm!")
                             }
                         })
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
@@ -345,6 +345,8 @@ declare_features! (
     (unstable, asm_const, "1.58.0", Some(93332)),
     /// Enables experimental inline assembly support for additional architectures.
     (unstable, asm_experimental_arch, "1.58.0", Some(93335)),
+    /// Allows using `label` operands in inline assembly.
+    (unstable, asm_goto, "CURRENT_RUSTC_VERSION", Some(119364)),
     /// Allows the `may_unwind` option in inline assembly.
     (unstable, asm_unwind, "1.58.0", Some(93334)),
     /// Allows users to enforce equality of associated constants `TraitImpl<AssocConst=3>`.
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
@@ -2631,6 +2631,9 @@ pub enum InlineAsmOperand<'hir> {
         path: QPath<'hir>,
         def_id: DefId,
     },
+    Label {
+        block: &'hir Block<'hir>,
+    },
 }
 
 impl<'hir> InlineAsmOperand<'hir> {
@@ -2640,7 +2643,10 @@ impl<'hir> InlineAsmOperand<'hir> {
             | Self::Out { reg, .. }
             | Self::InOut { reg, .. }
             | Self::SplitInOut { reg, .. } => Some(reg),
-            Self::Const { .. } | Self::SymFn { .. } | Self::SymStatic { .. } => None,
+            Self::Const { .. }
+            | Self::SymFn { .. }
+            | Self::SymStatic { .. }
+            | Self::Label { .. } => None,
         }
     }
 
@@ -2661,6 +2667,12 @@ pub struct InlineAsm<'hir> {
     pub line_spans: &'hir [Span],
 }
 
+impl InlineAsm<'_> {
+    pub fn contains_label(&self) -> bool {
+        self.operands.iter().any(|x| matches!(x.0, InlineAsmOperand::Label { .. }))
+    }
+}
+
 /// Represents a parameter in a function header.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
 pub struct Param<'hir> {
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
@@ -1217,6 +1217,7 @@ pub fn walk_inline_asm<'v, V: Visitor<'v>>(visitor: &mut V, asm: &'v InlineAsm<'
             InlineAsmOperand::Const { anon_const, .. }
             | InlineAsmOperand::SymFn { anon_const, .. } => visitor.visit_anon_const(anon_const),
             InlineAsmOperand::SymStatic { path, .. } => visitor.visit_qpath(path, id, *op_sp),
+            InlineAsmOperand::Label { block } => visitor.visit_block(block),
         }
     }
 }
diff --git a/compiler/rustc_hir_analysis/src/check/intrinsicck.rs b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
@@ -460,6 +460,8 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
                         }
                     };
                 }
+                // No special checking is needed for labels.
+                hir::InlineAsmOperand::Label { .. } => {}
             }
         }
     }
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
@@ -1255,6 +1255,10 @@ impl<'a> State<'a> {
                     s.space();
                     s.print_qpath(path, true);
                 }
+                hir::InlineAsmOperand::Label { block } => {
+                    s.head("label");
+                    s.print_block(block);
+                }
             },
             AsmArg::Options(opts) => {
                 s.word("options");
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
@@ -3243,6 +3243,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 // be well-formed.
                 hir::InlineAsmOperand::Const { .. } | hir::InlineAsmOperand::SymFn { .. } => {}
                 hir::InlineAsmOperand::SymStatic { .. } => {}
+                hir::InlineAsmOperand::Label { block } => {
+                    self.check_block_no_value(block);
+                }
             }
         }
         if asm.options.contains(ast::InlineAsmOptions::NORETURN) {
diff --git a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
@@ -293,6 +293,9 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                         | hir::InlineAsmOperand::Const { .. }
                         | hir::InlineAsmOperand::SymFn { .. }
                         | hir::InlineAsmOperand::SymStatic { .. } => {}
+                        hir::InlineAsmOperand::Label { block } => {
+                            self.walk_block(block);
+                        }
                     }
                 }
             }
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -650,6 +650,9 @@ impl<'tcx> Cx<'tcx> {
                         hir::InlineAsmOperand::SymStatic { path: _, def_id } => {
                             InlineAsmOperand::SymStatic { def_id }
                         }
+                        hir::InlineAsmOperand::Label { .. } => {
+                            todo!()
+                        }
                     })
                     .collect(),
                 options: asm.options,
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
@@ -446,7 +446,8 @@ fn collect_items_rec<'tcx>(
                         hir::InlineAsmOperand::In { .. }
                         | hir::InlineAsmOperand::Out { .. }
                         | hir::InlineAsmOperand::InOut { .. }
-                        | hir::InlineAsmOperand::SplitInOut { .. } => {
+                        | hir::InlineAsmOperand::SplitInOut { .. }
+                        | hir::InlineAsmOperand::Label { .. } => {
                             span_bug!(*op_sp, "invalid operand type for global_asm!")
                         }
                     }
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
@@ -427,7 +427,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Parses a block. No inner attributes are allowed.
-    pub(super) fn parse_block(&mut self) -> PResult<'a, P<Block>> {
+    pub fn parse_block(&mut self) -> PResult<'a, P<Block>> {
         let (attrs, block) = self.parse_inner_attrs_and_block()?;
         if let [.., last] = &*attrs {
             self.error_on_forbidden_inner_attr(
diff --git a/compiler/rustc_passes/src/liveness.rs b/compiler/rustc_passes/src/liveness.rs
@@ -446,6 +446,12 @@ impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
                 intravisit::walk_expr(self, expr);
             }
 
+            // Inline assembly may contain labels.
+            hir::ExprKind::InlineAsm(asm) if asm.contains_label() => {
+                self.add_live_node_for_node(expr.hir_id, ExprNode(expr.span, expr.hir_id));
+                intravisit::walk_expr(self, expr);
+            }
+
             // otherwise, live nodes are not required:
             hir::ExprKind::Index(..)
             | hir::ExprKind::Field(..)
@@ -1074,20 +1080,56 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
             | hir::ExprKind::Repeat(ref e, _) => self.propagate_through_expr(e, succ),
 
             hir::ExprKind::InlineAsm(asm) => {
+                //
+                //     (inputs)
+                //        |
+                //        v
+                //     (outputs)
+                //    /         \
+                //    |         |
+                //    v         v
+                // (labels)(fallthrough)
+                //    |         |
+                //    v         v
+                // ( succ / exit_ln )
+
                 // Handle non-returning asm
                 let mut succ = if asm.options.contains(InlineAsmOptions::NORETURN) {
                     self.exit_ln
                 } else {
                     succ
                 };
 
+                // Do a first pass for labels only
+                if asm.contains_label() {
+                    let ln = self.live_node(expr.hir_id, expr.span);
+                    self.init_from_succ(ln, succ);
+                    for (op, _op_sp) in asm.operands.iter().rev() {
+                        match op {
+                            hir::InlineAsmOperand::Label { block } => {
+                                let label_ln = self.propagate_through_block(block, succ);
+                                self.merge_from_succ(ln, label_ln);
+                            }
+                            hir::InlineAsmOperand::In { .. }
+                            | hir::InlineAsmOperand::Out { .. }
+                            | hir::InlineAsmOperand::InOut { .. }
+                            | hir::InlineAsmOperand::SplitInOut { .. }
+                            | hir::InlineAsmOperand::Const { .. }
+                            | hir::InlineAsmOperand::SymFn { .. }
+                            | hir::InlineAsmOperand::SymStatic { .. } => {}
+                        }
+                    }
+                    succ = ln;
+                }
+
                 // Do a first pass for writing outputs only
                 for (op, _op_sp) in asm.operands.iter().rev() {
                     match op {
                         hir::InlineAsmOperand::In { .. }
                         | hir::InlineAsmOperand::Const { .. }
                         | hir::InlineAsmOperand::SymFn { .. }
-                        | hir::InlineAsmOperand::SymStatic { .. } => {}
+                        | hir::InlineAsmOperand::SymStatic { .. }
+                        | hir::InlineAsmOperand::Label { .. } => {}
                         hir::InlineAsmOperand::Out { expr, .. } => {
                             if let Some(expr) = expr {
                                 succ = self.write_place(expr, succ, ACC_WRITE);
@@ -1126,7 +1168,8 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
                         }
                         hir::InlineAsmOperand::Const { .. }
                         | hir::InlineAsmOperand::SymFn { .. }
-                        | hir::InlineAsmOperand::SymStatic { .. } => {}
+                        | hir::InlineAsmOperand::SymStatic { .. }
+                        | hir::InlineAsmOperand::Label { .. } => {}
                     }
                 }
                 succ
diff --git a/compiler/rustc_passes/src/naked_functions.rs b/compiler/rustc_passes/src/naked_functions.rs
@@ -237,7 +237,8 @@ impl<'tcx> CheckInlineAssembly<'tcx> {
                 InlineAsmOperand::In { .. }
                 | InlineAsmOperand::Out { .. }
                 | InlineAsmOperand::InOut { .. }
-                | InlineAsmOperand::SplitInOut { .. } => Some(op_sp),
+                | InlineAsmOperand::SplitInOut { .. }
+                | InlineAsmOperand::Label { .. } => Some(op_sp),
             })
             .collect();
         if !unsupported_operands.is_empty() {
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
@@ -1235,6 +1235,7 @@ impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast,
                     self.resolve_anon_const(anon_const, AnonConstKind::InlineConst);
                 }
                 InlineAsmOperand::Sym { sym } => self.visit_inline_asm_sym(sym),
+                InlineAsmOperand::Label { block } => self.visit_block(block),
             }
         }
     }
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
@@ -403,6 +403,7 @@ symbols! {
         asm,
         asm_const,
         asm_experimental_arch,
+        asm_goto,
         asm_sym,
         asm_unwind,
         assert,

Original file line number	Diff line number	Diff line change
`@@ -2272,6 +2272,9 @@ pub enum InlineAsmOperand {`
`2272`	`2272`	`Sym {`
`2273`	`2273`	`sym: InlineAsmSym,`
`2274`	`2274`	`},`
	`2275`	`+ Label {`
	`2276`	`+ block: P<Block>,`
	`2277`	`+ },`
`2275`	`2278`	`}`
`2276`	`2279`
`2277`	`2280`	`impl InlineAsmOperand {`
`@@ -2281,7 +2284,7 @@ impl InlineAsmOperand {`
`2281`	`2284`	`\| Self::Out { reg, .. }`
`2282`	`2285`	`\| Self::InOut { reg, .. }`
`2283`	`2286`	`\| Self::SplitInOut { reg, .. } => Some(reg),`
`2284`		`- Self::Const { .. } \| Self::Sym { .. } => None,`
	`2287`	`+ Self::Const { .. } \| Self::Sym { .. } \| Self::Label { .. } => None,`
`2285`	`2288`	`}`
`2286`	`2289`	`}`
`2287`	`2290`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1308,6 +1308,7 @@ pub fn noop_visit_inline_asm<T: MutVisitor>(asm: &mut InlineAsm, vis: &mut T) {`
`1308`	`1308`	`}`
`1309`	`1309`	`InlineAsmOperand::Const { anon_const } => vis.visit_anon_const(anon_const),`
`1310`	`1310`	`InlineAsmOperand::Sym { sym } => vis.visit_inline_asm_sym(sym),`
	`1311`	`+ InlineAsmOperand::Label { block } => vis.visit_block(block),`
`1311`	`1312`	`}`
`1312`	`1313`	`}`
`1313`	`1314`	`}`
Original file line number	Diff line number	Diff line change
`@@ -763,6 +763,7 @@ pub fn walk_inline_asm<'a, V: Visitor<'a>>(visitor: &mut V, asm: &'a InlineAsm)`
`763`	`763`	`}`
`764`	`764`	`InlineAsmOperand::Const { anon_const, .. } => visitor.visit_anon_const(anon_const),`
`765`	`765`	`InlineAsmOperand::Sym { sym } => visitor.visit_inline_asm_sym(sym),`
	`766`	`+ InlineAsmOperand::Label { block } => visitor.visit_block(block),`
`766`	`767`	`}`
`767`	`768`	`}`
`768`	`769`	`}`
Original file line number	Diff line number	Diff line change
`@@ -1298,6 +1298,10 @@ impl<'a> State<'a> {`
`1298`	`1298`	`s.print_path(&sym.path, true, 0);`
`1299`	`1299`	`}`
`1300`	`1300`	`}`
	`1301`	`+ InlineAsmOperand::Label { block } => {`
	`1302`	`+ s.head("label");`
	`1303`	`+ s.print_block(block);`
	`1304`	`+ }`
`1301`	`1305`	`}`
`1302`	`1306`	`}`
`1303`	`1307`	`AsmArg::ClobberAbi(abi) => {`