Auto merge of #78319 - jonas-schievink:rollup-vzj8a6l, r=jonas-schievink

Rollup of 15 pull requests

Successful merges:

 - #76649 (Add a spin loop hint for Arc::downgrade)
 - #77392 (add `insert` to `Option`)
 - #77716 (Revert "Allow dynamic linking for iOS/tvOS targets.")
 - #78109 (Check for exhaustion in RangeInclusive::contains and slicing)
 - #78198 (Simplify assert terminator only if condition evaluates to expected value)
 - #78243 (--test-args flag description)
 - #78249 (improve const infer error)
 - #78250 (Document inline-const)
 - #78264 (Add regression test for issue-77475)
 - #78274 (Update description of Empty Enum for accuracy)
 - #78278 (move `visit_predicate` into `TypeVisitor`)
 - #78292 (Loop instead of recursion)
 - #78293 (Always store Rustdoc theme when it's changed)
 - #78300 (Make codegen coverage_context optional, and check)
 - #78307 (Revert "Set .llvmbc and .llvmcmd sections as allocatable")

Failed merges:

r? `@ghost`

compiler/rustc_ast_lowering/src/pat.rs

@@ -10,82 +10,90 @@ use rustc_span::symbol::Ident;
 use rustc_span::{source_map::Spanned, Span};
 
 impl<'a, 'hir> LoweringContext<'a, 'hir> {
-    crate fn lower_pat(&mut self, p: &Pat) -> &'hir hir::Pat<'hir> {
+    crate fn lower_pat(&mut self, mut pattern: &Pat) -> &'hir hir::Pat<'hir> {
         ensure_sufficient_stack(|| {
-            let node = match p.kind {
-                PatKind::Wild => hir::PatKind::Wild,
-                PatKind::Ident(ref binding_mode, ident, ref sub) => {
-                    let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
-                    let node = self.lower_pat_ident(p, binding_mode, ident, lower_sub);
-                    node
-                }
-                PatKind::Lit(ref e) => hir::PatKind::Lit(self.lower_expr(e)),
-                PatKind::TupleStruct(ref path, ref pats) => {
-                    let qpath = self.lower_qpath(
-                        p.id,
-                        &None,
-                        path,
-                        ParamMode::Optional,
-                        ImplTraitContext::disallowed(),
-                    );
-                    let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
-                    hir::PatKind::TupleStruct(qpath, pats, ddpos)
-                }
-                PatKind::Or(ref pats) => hir::PatKind::Or(
-                    self.arena.alloc_from_iter(pats.iter().map(|x| self.lower_pat(x))),
-                ),
-                PatKind::Path(ref qself, ref path) => {
-                    let qpath = self.lower_qpath(
-                        p.id,
-                        qself,
-                        path,
-                        ParamMode::Optional,
-                        ImplTraitContext::disallowed(),
-                    );
-                    hir::PatKind::Path(qpath)
-                }
-                PatKind::Struct(ref path, ref fields, etc) => {
-                    let qpath = self.lower_qpath(
-                        p.id,
-                        &None,
-                        path,
-                        ParamMode::Optional,
-                        ImplTraitContext::disallowed(),
-                    );
+            // loop here to avoid recursion
+            let node = loop {
+                match pattern.kind {
+                    PatKind::Wild => break hir::PatKind::Wild,
+                    PatKind::Ident(ref binding_mode, ident, ref sub) => {
+                        let lower_sub = |this: &mut Self| sub.as_ref().map(|s| this.lower_pat(&*s));
+                        break self.lower_pat_ident(pattern, binding_mode, ident, lower_sub);
+                    }
+                    PatKind::Lit(ref e) => break hir::PatKind::Lit(self.lower_expr(e)),
+                    PatKind::TupleStruct(ref path, ref pats) => {
+                        let qpath = self.lower_qpath(
+                            pattern.id,
+                            &None,
+                            path,
+                            ParamMode::Optional,
+                            ImplTraitContext::disallowed(),
+                        );
+                        let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
+                        break hir::PatKind::TupleStruct(qpath, pats, ddpos);
+                    }
+                    PatKind::Or(ref pats) => {
+                        break hir::PatKind::Or(
+                            self.arena.alloc_from_iter(pats.iter().map(|x| self.lower_pat(x))),
+                        );
+                    }
+                    PatKind::Path(ref qself, ref path) => {
+                        let qpath = self.lower_qpath(
+                            pattern.id,
+                            qself,
+                            path,
+                            ParamMode::Optional,
+                            ImplTraitContext::disallowed(),
+                        );
+                        break hir::PatKind::Path(qpath);
+                    }
+                    PatKind::Struct(ref path, ref fields, etc) => {
+                        let qpath = self.lower_qpath(
+                            pattern.id,
+                            &None,
+                            path,
+                            ParamMode::Optional,
+                            ImplTraitContext::disallowed(),
+                        );
 
-                    let fs = self.arena.alloc_from_iter(fields.iter().map(|f| hir::FieldPat {
-                        hir_id: self.next_id(),
-                        ident: f.ident,
-                        pat: self.lower_pat(&f.pat),
-                        is_shorthand: f.is_shorthand,
-                        span: f.span,
-                    }));
-                    hir::PatKind::Struct(qpath, fs, etc)
-                }
-                PatKind::Tuple(ref pats) => {
-                    let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");
-                    hir::PatKind::Tuple(pats, ddpos)
-                }
-                PatKind::Box(ref inner) => hir::PatKind::Box(self.lower_pat(inner)),
-                PatKind::Ref(ref inner, mutbl) => hir::PatKind::Ref(self.lower_pat(inner), mutbl),
-                PatKind::Range(ref e1, ref e2, Spanned { node: ref end, .. }) => {
-                    hir::PatKind::Range(
-                        e1.as_deref().map(|e| self.lower_expr(e)),
-                        e2.as_deref().map(|e| self.lower_expr(e)),
-                        self.lower_range_end(end, e2.is_some()),
-                    )
-                }
-                PatKind::Slice(ref pats) => self.lower_pat_slice(pats),
-                PatKind::Rest => {
-                    // If we reach here the `..` pattern is not semantically allowed.
-                    self.ban_illegal_rest_pat(p.span)
+                        let fs = self.arena.alloc_from_iter(fields.iter().map(|f| hir::FieldPat {
+                            hir_id: self.next_id(),
+                            ident: f.ident,
+                            pat: self.lower_pat(&f.pat),
+                            is_shorthand: f.is_shorthand,
+                            span: f.span,
+                        }));
+                        break hir::PatKind::Struct(qpath, fs, etc);
+                    }
+                    PatKind::Tuple(ref pats) => {
+                        let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple");
+                        break hir::PatKind::Tuple(pats, ddpos);
+                    }
+                    PatKind::Box(ref inner) => {
+                        break hir::PatKind::Box(self.lower_pat(inner));
+                    }
+                    PatKind::Ref(ref inner, mutbl) => {
+                        break hir::PatKind::Ref(self.lower_pat(inner), mutbl);
+                    }
+                    PatKind::Range(ref e1, ref e2, Spanned { node: ref end, .. }) => {
+                        break hir::PatKind::Range(
+                            e1.as_deref().map(|e| self.lower_expr(e)),
+                            e2.as_deref().map(|e| self.lower_expr(e)),
+                            self.lower_range_end(end, e2.is_some()),
+                        );
+                    }
+                    PatKind::Slice(ref pats) => break self.lower_pat_slice(pats),
+                    PatKind::Rest => {
+                        // If we reach here the `..` pattern is not semantically allowed.
+                        break self.ban_illegal_rest_pat(pattern.span);
+                    }
+                    // return inner to be processed in next loop
+                    PatKind::Paren(ref inner) => pattern = inner,
+                    PatKind::MacCall(_) => panic!("{:?} shouldn't exist here", pattern.span),
                 }
-                // FIXME: consider not using recursion to lower this.
-                PatKind::Paren(ref inner) => return self.lower_pat(inner),
-                PatKind::MacCall(_) => panic!("{:?} shouldn't exist here", p.span),
             };
 
-            self.pat_with_node_id_of(p, node)
+            self.pat_with_node_id_of(pattern, node)
         })
     }
 

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -936,8 +936,8 @@ unsafe fn embed_bitcode(
         llvm::LLVMRustAppendModuleInlineAsm(llmod, asm.as_ptr().cast(), asm.len());
     } else {
         let asm = "
-            .section .llvmbc,\"a\"
-            .section .llvmcmd,\"a\"
+            .section .llvmbc,\"e\"
+            .section .llvmcmd,\"e\"
         ";
         llvm::LLVMRustAppendModuleInlineAsm(llmod, asm.as_ptr().cast(), asm.len());
     }

compiler/rustc_codegen_llvm/src/context.rs

@@ -324,8 +324,8 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
     }
 
     #[inline]
-    pub fn coverage_context(&'a self) -> &'a coverageinfo::CrateCoverageContext<'tcx> {
-        self.coverage_cx.as_ref().unwrap()
+    pub fn coverage_context(&'a self) -> Option<&'a coverageinfo::CrateCoverageContext<'tcx>> {
+        self.coverage_cx.as_ref()
     }
 }
 

compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs

@@ -26,7 +26,10 @@ use tracing::debug;
 /// undocumented details in Clang's implementation (that may or may not be important) were also
 /// replicated for Rust's Coverage Map.
 pub fn finalize<'ll, 'tcx>(cx: &CodegenCx<'ll, 'tcx>) {
-    let function_coverage_map = cx.coverage_context().take_function_coverage_map();
+    let function_coverage_map = match cx.coverage_context() {
+        Some(ctx) => ctx.take_function_coverage_map(),
+        None => return,
+    };
     if function_coverage_map.is_empty() {
         // This module has no functions with coverage instrumentation
         return;

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -64,17 +64,22 @@ impl CoverageInfoBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
         function_source_hash: u64,
         id: CounterValueReference,
         region: CodeRegion,
-    ) {
-        debug!(
-            "adding counter to coverage_regions: instance={:?}, function_source_hash={}, id={:?}, \
-             at {:?}",
-            instance, function_source_hash, id, region,
-        );
-        let mut coverage_regions = self.coverage_context().function_coverage_map.borrow_mut();
-        coverage_regions
-            .entry(instance)
-            .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
-            .add_counter(function_source_hash, id, region);
+    ) -> bool {
+        if let Some(coverage_context) = self.coverage_context() {
+            debug!(
+                "adding counter to coverage_regions: instance={:?}, function_source_hash={}, id={:?}, \
+                at {:?}",
+                instance, function_source_hash, id, region,
+            );
+            let mut coverage_regions = coverage_context.function_coverage_map.borrow_mut();
+            coverage_regions
+                .entry(instance)
+                .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
+                .add_counter(function_source_hash, id, region);
+            true
+        } else {
+            false
+        }
     }
 
     fn add_counter_expression_region(
@@ -85,29 +90,39 @@ impl CoverageInfoBuilderMethods<'tcx> for Builder<'a, 'll, 'tcx> {
         op: Op,
         rhs: ExpressionOperandId,
         region: CodeRegion,
-    ) {
-        debug!(
-            "adding counter expression to coverage_regions: instance={:?}, id={:?}, {:?} {:?} {:?}, \
-             at {:?}",
-            instance, id, lhs, op, rhs, region,
-        );
-        let mut coverage_regions = self.coverage_context().function_coverage_map.borrow_mut();
-        coverage_regions
-            .entry(instance)
-            .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
-            .add_counter_expression(id, lhs, op, rhs, region);
+    ) -> bool {
+        if let Some(coverage_context) = self.coverage_context() {
+            debug!(
+                "adding counter expression to coverage_regions: instance={:?}, id={:?}, {:?} {:?} {:?}, \
+                at {:?}",
+                instance, id, lhs, op, rhs, region,
+            );
+            let mut coverage_regions = coverage_context.function_coverage_map.borrow_mut();
+            coverage_regions
+                .entry(instance)
+                .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
+                .add_counter_expression(id, lhs, op, rhs, region);
+            true
+        } else {
+            false
+        }
     }
 
-    fn add_unreachable_region(&mut self, instance: Instance<'tcx>, region: CodeRegion) {
-        debug!(
-            "adding unreachable code to coverage_regions: instance={:?}, at {:?}",
-            instance, region,
-        );
-        let mut coverage_regions = self.coverage_context().function_coverage_map.borrow_mut();
-        coverage_regions
-            .entry(instance)
-            .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
-            .add_unreachable_region(region);
+    fn add_unreachable_region(&mut self, instance: Instance<'tcx>, region: CodeRegion) -> bool {
+        if let Some(coverage_context) = self.coverage_context() {
+            debug!(
+                "adding unreachable code to coverage_regions: instance={:?}, at {:?}",
+                instance, region,
+            );
+            let mut coverage_regions = coverage_context.function_coverage_map.borrow_mut();
+            coverage_regions
+                .entry(instance)
+                .or_insert_with(|| FunctionCoverage::new(self.tcx, instance))
+                .add_unreachable_region(region);
+            true
+        } else {
+            false
+        }
     }
 }
 

compiler/rustc_codegen_ssa/src/mir/coverageinfo.rs

@@ -10,19 +10,19 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let Coverage { kind, code_region } = coverage;
         match kind {
             CoverageKind::Counter { function_source_hash, id } => {
-                bx.add_counter_region(self.instance, function_source_hash, id, code_region);
+                if bx.add_counter_region(self.instance, function_source_hash, id, code_region) {
+                    let coverageinfo = bx.tcx().coverageinfo(self.instance.def_id());
 
-                let coverageinfo = bx.tcx().coverageinfo(self.instance.def_id());
-
-                let fn_name = bx.create_pgo_func_name_var(self.instance);
-                let hash = bx.const_u64(function_source_hash);
-                let num_counters = bx.const_u32(coverageinfo.num_counters);
-                let id = bx.const_u32(u32::from(id));
-                debug!(
-                    "codegen intrinsic instrprof.increment(fn_name={:?}, hash={:?}, num_counters={:?}, index={:?})",
-                    fn_name, hash, num_counters, id,
-                );
-                bx.instrprof_increment(fn_name, hash, num_counters, id);
+                    let fn_name = bx.create_pgo_func_name_var(self.instance);
+                    let hash = bx.const_u64(function_source_hash);
+                    let num_counters = bx.const_u32(coverageinfo.num_counters);
+                    let id = bx.const_u32(u32::from(id));
+                    debug!(
+                        "codegen intrinsic instrprof.increment(fn_name={:?}, hash={:?}, num_counters={:?}, index={:?})",
+                        fn_name, hash, num_counters, id,
+                    );
+                    bx.instrprof_increment(fn_name, hash, num_counters, id);
+                }
             }
             CoverageKind::Expression { id, lhs, op, rhs } => {
                 bx.add_counter_expression_region(self.instance, id, lhs, op, rhs, code_region);

compiler/rustc_codegen_ssa/src/traits/coverageinfo.rs

@@ -9,14 +9,18 @@ pub trait CoverageInfoMethods: BackendTypes {
 pub trait CoverageInfoBuilderMethods<'tcx>: BackendTypes {
     fn create_pgo_func_name_var(&self, instance: Instance<'tcx>) -> Self::Value;
 
+    /// Returns true if the counter was added to the coverage map; false if `-Z instrument-coverage`
+    /// is not enabled (a coverage map is not being generated).
     fn add_counter_region(
         &mut self,
         instance: Instance<'tcx>,
         function_source_hash: u64,
         id: CounterValueReference,
         region: CodeRegion,
-    );
+    ) -> bool;
 
+    /// Returns true if the expression was added to the coverage map; false if
+    /// `-Z instrument-coverage` is not enabled (a coverage map is not being generated).
     fn add_counter_expression_region(
         &mut self,
         instance: Instance<'tcx>,
@@ -25,7 +29,9 @@ pub trait CoverageInfoBuilderMethods<'tcx>: BackendTypes {
         op: Op,
         rhs: ExpressionOperandId,
         region: CodeRegion,
-    );
+    ) -> bool;
 
-    fn add_unreachable_region(&mut self, instance: Instance<'tcx>, region: CodeRegion);
+    /// Returns true if the region was added to the coverage map; false if `-Z instrument-coverage`
+    /// is not enabled (a coverage map is not being generated).
+    fn add_unreachable_region(&mut self, instance: Instance<'tcx>, region: CodeRegion) -> bool;
 }

compiler/rustc_middle/src/infer/unify_key.rs

@@ -175,19 +175,15 @@ impl<'tcx> UnifyKey for ty::ConstVid<'tcx> {
 impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
     type Error = (&'tcx ty::Const<'tcx>, &'tcx ty::Const<'tcx>);
 
-    fn unify_values(value1: &Self, value2: &Self) -> Result<Self, Self::Error> {
-        let (val, span) = match (value1.val, value2.val) {
+    fn unify_values(&value1: &Self, &value2: &Self) -> Result<Self, Self::Error> {
+        Ok(match (value1.val, value2.val) {
             (ConstVariableValue::Known { .. }, ConstVariableValue::Known { .. }) => {
                 bug!("equating two const variables, both of which have known values")
             }
 
             // If one side is known, prefer that one.
-            (ConstVariableValue::Known { .. }, ConstVariableValue::Unknown { .. }) => {
-                (value1.val, value1.origin.span)
-            }
-            (ConstVariableValue::Unknown { .. }, ConstVariableValue::Known { .. }) => {
-                (value2.val, value2.origin.span)
-            }
+            (ConstVariableValue::Known { .. }, ConstVariableValue::Unknown { .. }) => value1,
+            (ConstVariableValue::Unknown { .. }, ConstVariableValue::Known { .. }) => value2,
 
             // If both sides are *unknown*, it hardly matters, does it?
             (
@@ -200,16 +196,11 @@ impl<'tcx> UnifyValue for ConstVarValue<'tcx> {
                 // universe is the minimum of the two universes, because that is
                 // the one which contains the fewest names in scope.
                 let universe = cmp::min(universe1, universe2);
-                (ConstVariableValue::Unknown { universe }, value1.origin.span)
+                ConstVarValue {
+                    val: ConstVariableValue::Unknown { universe },
+                    origin: value1.origin,
+                }
             }
-        };
-
-        Ok(ConstVarValue {
-            origin: ConstVariableOrigin {
-                kind: ConstVariableOriginKind::ConstInference,
-                span: span,
-            },
-            val,
         })
     }
 }