Vendor things

third-party/vendor/bindgen/ir/analysis/has_float.rs

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+//! Determining which types has float.
+
+use super::{generate_dependencies, ConstrainResult, MonotoneFramework};
+use crate::ir::comp::Field;
+use crate::ir::comp::FieldMethods;
+use crate::ir::context::{BindgenContext, ItemId};
+use crate::ir::traversal::EdgeKind;
+use crate::ir::ty::TypeKind;
+use crate::{HashMap, HashSet};
+
+/// An analysis that finds for each IR item whether it has float or not.
+///
+/// We use the monotone constraint function `has_float`,
+/// defined as follows:
+///
+/// * If T is float or complex float, T trivially has.
+/// * If T is a type alias, a templated alias or an indirection to another type,
+///   it has float if the type T refers to has.
+/// * If T is a compound type, it has float if any of base memter or field
+///   has.
+/// * If T is an instantiation of an abstract template definition, T has
+///   float if any of the template arguments or template definition
+///   has.
+#[derive(Debug, Clone)]
+pub struct HasFloat<'ctx> {
+    ctx: &'ctx BindgenContext,
+
+    // The incremental result of this analysis's computation. Everything in this
+    // set has float.
+    has_float: HashSet<ItemId>,
+
+    // Dependencies saying that if a key ItemId has been inserted into the
+    // `has_float` set, then each of the ids in Vec<ItemId> need to be
+    // considered again.
+    //
+    // This is a subset of the natural IR graph with reversed edges, where we
+    // only include the edges from the IR graph that can affect whether a type
+    // has float or not.
+    dependencies: HashMap<ItemId, Vec<ItemId>>,
+}
+
+impl<'ctx> HasFloat<'ctx> {
+    fn consider_edge(kind: EdgeKind) -> bool {
+        match kind {
+            EdgeKind::BaseMember |
+            EdgeKind::Field |
+            EdgeKind::TypeReference |
+            EdgeKind::VarType |
+            EdgeKind::TemplateArgument |
+            EdgeKind::TemplateDeclaration |
+            EdgeKind::TemplateParameterDefinition => true,
+
+            EdgeKind::Constructor |
+            EdgeKind::Destructor |
+            EdgeKind::FunctionReturn |
+            EdgeKind::FunctionParameter |
+            EdgeKind::InnerType |
+            EdgeKind::InnerVar |
+            EdgeKind::Method => false,
+            EdgeKind::Generic => false,
+        }
+    }
+
+    fn insert<Id: Into<ItemId>>(&mut self, id: Id) -> ConstrainResult {
+        let id = id.into();
+        trace!("inserting {:?} into the has_float set", id);
+
+        let was_not_already_in_set = self.has_float.insert(id);
+        assert!(
+            was_not_already_in_set,
+            "We shouldn't try and insert {:?} twice because if it was \
+             already in the set, `constrain` should have exited early.",
+            id
+        );
+
+        ConstrainResult::Changed
+    }
+}
+
+impl<'ctx> MonotoneFramework for HasFloat<'ctx> {
+    type Node = ItemId;
+    type Extra = &'ctx BindgenContext;
+    type Output = HashSet<ItemId>;
+
+    fn new(ctx: &'ctx BindgenContext) -> HasFloat<'ctx> {
+        let has_float = HashSet::default();
+        let dependencies = generate_dependencies(ctx, Self::consider_edge);
+
+        HasFloat {
+            ctx,
+            has_float,
+            dependencies,
+        }
+    }
+
+    fn initial_worklist(&self) -> Vec<ItemId> {
+        self.ctx.allowlisted_items().iter().cloned().collect()
+    }
+
+    fn constrain(&mut self, id: ItemId) -> ConstrainResult {
+        trace!("constrain: {:?}", id);
+
+        if self.has_float.contains(&id) {
+            trace!("    already know it do not have float");
+            return ConstrainResult::Same;
+        }
+
+        let item = self.ctx.resolve_item(id);
+        let ty = match item.as_type() {
+            Some(ty) => ty,
+            None => {
+                trace!("    not a type; ignoring");
+                return ConstrainResult::Same;
+            }
+        };
+
+        match *ty.kind() {
+            TypeKind::Void |
+            TypeKind::NullPtr |
+            TypeKind::Int(..) |
+            TypeKind::Function(..) |
+            TypeKind::Enum(..) |
+            TypeKind::Reference(..) |
+            TypeKind::TypeParam |
+            TypeKind::Opaque |
+            TypeKind::Pointer(..) |
+            TypeKind::UnresolvedTypeRef(..) |
+            TypeKind::ObjCInterface(..) |
+            TypeKind::ObjCId |
+            TypeKind::ObjCSel => {
+                trace!("    simple type that do not have float");
+                ConstrainResult::Same
+            }
+
+            TypeKind::Float(..) | TypeKind::Complex(..) => {
+                trace!("    float type has float");
+                self.insert(id)
+            }
+
+            TypeKind::Array(t, _) => {
+                if self.has_float.contains(&t.into()) {
+                    trace!(
+                        "    Array with type T that has float also has float"
+                    );
+                    return self.insert(id);
+                }
+                trace!("    Array with type T that do not have float also do not have float");
+                ConstrainResult::Same
+            }
+            TypeKind::Vector(t, _) => {
+                if self.has_float.contains(&t.into()) {
+                    trace!(
+                        "    Vector with type T that has float also has float"
+                    );
+                    return self.insert(id);
+                }
+                trace!("    Vector with type T that do not have float also do not have float");
+                ConstrainResult::Same
+            }
+
+            TypeKind::ResolvedTypeRef(t) |
+            TypeKind::TemplateAlias(t, _) |
+            TypeKind::Alias(t) |
+            TypeKind::BlockPointer(t) => {
+                if self.has_float.contains(&t.into()) {
+                    trace!(
+                        "    aliases and type refs to T which have float \
+                         also have float"
+                    );
+                    self.insert(id)
+                } else {
+                    trace!("    aliases and type refs to T which do not have float \
+                            also do not have floaarrayt");
+                    ConstrainResult::Same
+                }
+            }
+
+            TypeKind::Comp(ref info) => {
+                let bases_have = info
+                    .base_members()
+                    .iter()
+                    .any(|base| self.has_float.contains(&base.ty.into()));
+                if bases_have {
+                    trace!("    bases have float, so we also have");
+                    return self.insert(id);
+                }
+                let fields_have = info.fields().iter().any(|f| match *f {
+                    Field::DataMember(ref data) => {
+                        self.has_float.contains(&data.ty().into())
+                    }
+                    Field::Bitfields(ref bfu) => bfu
+                        .bitfields()
+                        .iter()
+                        .any(|b| self.has_float.contains(&b.ty().into())),
+                });
+                if fields_have {
+                    trace!("    fields have float, so we also have");
+                    return self.insert(id);
+                }
+
+                trace!("    comp doesn't have float");
+                ConstrainResult::Same
+            }
+
+            TypeKind::TemplateInstantiation(ref template) => {
+                let args_have = template
+                    .template_arguments()
+                    .iter()
+                    .any(|arg| self.has_float.contains(&arg.into()));
+                if args_have {
+                    trace!(
+                        "    template args have float, so \
+                         insantiation also has float"
+                    );
+                    return self.insert(id);
+                }
+
+                let def_has = self
+                    .has_float
+                    .contains(&template.template_definition().into());
+                if def_has {
+                    trace!(
+                        "    template definition has float, so \
+                         insantiation also has"
+                    );
+                    return self.insert(id);
+                }
+
+                trace!("    template instantiation do not have float");
+                ConstrainResult::Same
+            }
+        }
+    }
+
+    fn each_depending_on<F>(&self, id: ItemId, mut f: F)
+    where
+        F: FnMut(ItemId),
+    {
+        if let Some(edges) = self.dependencies.get(&id) {
+            for item in edges {
+                trace!("enqueue {:?} into worklist", item);
+                f(*item);
+            }
+        }
+    }
+}
+
+impl<'ctx> From<HasFloat<'ctx>> for HashSet<ItemId> {
+    fn from(analysis: HasFloat<'ctx>) -> Self {
+        analysis.has_float
+    }
+}