Add --blocklist-file option (rust-lang#2097)

Update Item to hold a `clang::SourceLocation` and use this to allow
blocklisting based on filename.

The existing code has a special case that always maps <stdint.h> integer
types to corresponding Rust integer types, even if the C types are
blocklisted.  To match this special case behaviour, also treat these
C <stdint.h> types as being eligible for derived Copy/Clone/Debug
traits.

Fixes rust-lang#2096

Author: daviddrysdale

CONTRIBUTING.md

@@ -247,8 +247,8 @@ See [./csmith-fuzzing/README.md](./csmith-fuzzing/README.md) for details.
 
 The `tests/quickchecking` crate generates property tests for `bindgen`.
 From the crate's directory you can run the tests with `cargo run`. For details
-on additional configuration including how to preserve / inspect the generated 
-property tests, see 
+on additional configuration including how to preserve / inspect the generated
+property tests, see
 [./tests/quickchecking/README.md](./tests/quickchecking/README.md).
 
 ## Code Overview
@@ -298,6 +298,8 @@ looking at. Here is a summary of the IR types and their relationships:
             * Its type's `ItemId`
             * Optionally, a mangled name
             * Optionally, a value
+    * An optional `clang::SourceLocation` that holds the first source code
+      location where the `Item` was encountered.
 
 The IR forms a graph of interconnected and inter-referencing types and
 functions. The `ir::traversal` module provides IR graph traversal

book/src/blocklisting.md

@@ -2,8 +2,7 @@
 
 If you need to provide your own custom translation of some type (for example,
 because you need to wrap one of its fields in an `UnsafeCell`), you can
-explicitly blocklist
- generation of its definition. Uses of the blocklisted type
+explicitly blocklist generation of its definition. Uses of the blocklisted type
 will still appear in other types' definitions. (If you don't want the type to
 appear in the bindings at
 all, [make it opaque](./opaque.md) instead of
@@ -13,14 +12,25 @@ Blocklisted types are pessimistically assumed not to be able to `derive` any
 traits, which can transitively affect other types' ability to `derive` traits or
 not.
 
+The `blocklist-file` option also allows the blocklisting of all items from a
+particular path regex, for example to block all types defined in system headers
+that are transitively included.
+
 ### Library
 
+* [`bindgen::Builder::blocklist_file`](https://docs.rs/bindgen/latest/bindgen/struct.Builder.html#method.blocklist_file)
+* [`bindgen::Builder::blocklist_function`](https://docs.rs/bindgen/latest/bindgen/struct.Builder.html#method.blocklist_function)
+* [`bindgen::Builder::blocklist_item`](https://docs.rs/bindgen/latest/bindgen/struct.Builder.html#method.blocklist_item)
 * [`bindgen::Builder::blocklist_type`](https://docs.rs/bindgen/latest/bindgen/struct.Builder.html#method.blocklist_type)
 
 ### Command Line
 
+* `--blocklist-file <path>`
+* `--blocklist-function <function>`
+* `--blocklist-item <item>`
 * `--blocklist-type <type>`
 
+
 ### Annotations
 
 ```cpp

src/clang.rs

@@ -1401,6 +1401,12 @@ impl fmt::Display for SourceLocation {
     }
 }
 
+impl fmt::Debug for SourceLocation {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "{}", self)
+    }
+}
+
 /// A comment in the source text.
 ///
 /// Comments are sort of parsed by Clang, and have a tree structure.

src/ir/context.rs

@@ -1423,7 +1423,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
 
     fn build_root_module(id: ItemId) -> Item {
         let module = Module::new(Some("root".into()), ModuleKind::Normal);
-        Item::new(id, None, None, id, ItemKind::Module(module))
+        Item::new(id, None, None, id, ItemKind::Module(module), None)
     }
 
     /// Get the root module.
@@ -1733,6 +1733,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
                             None,
                             self.current_module.into(),
                             ItemKind::Type(sub_ty),
+                            Some(child.location()),
                         );
 
                         // Bypass all the validations in add_item explicitly.
@@ -1797,6 +1798,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
             None,
             self.current_module.into(),
             ItemKind::Type(ty),
+            Some(location.location()),
         );
 
         // Bypass all the validations in add_item explicitly.
@@ -1930,6 +1932,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
     ) -> TypeId {
         let spelling = ty.spelling();
         let layout = ty.fallible_layout(self).ok();
+        let location = ty.declaration().location();
         let type_kind = TypeKind::ResolvedTypeRef(wrapped_id);
         let ty = Type::new(Some(spelling), layout, type_kind, is_const);
         let item = Item::new(
@@ -1938,6 +1941,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
             None,
             parent_id.unwrap_or_else(|| self.current_module.into()),
             ItemKind::Type(ty),
+            Some(location),
         );
         self.add_builtin_item(item);
         with_id.as_type_id_unchecked()
@@ -1998,6 +2002,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
         let spelling = ty.spelling();
         let is_const = ty.is_const();
         let layout = ty.fallible_layout(self).ok();
+        let location = ty.declaration().location();
         let ty = Type::new(Some(spelling), layout, type_kind, is_const);
         let id = self.next_item_id();
         let item = Item::new(
@@ -2006,6 +2011,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
             None,
             self.root_module.into(),
             ItemKind::Type(ty),
+            Some(location),
         );
         self.add_builtin_item(item);
         Some(id.as_type_id_unchecked())
@@ -2194,6 +2200,7 @@ If you encounter an error missing from this list, please file an issue or a PR!"
             None,
             self.current_module.into(),
             ItemKind::Module(module),
+            Some(cursor.location()),
         );
 
         let module_id = module.id().as_module_id_unchecked();
@@ -2241,11 +2248,6 @@ If you encounter an error missing from this list, please file an issue or a PR!"
         assert!(self.in_codegen_phase());
         assert!(self.current_module == self.root_module);
 
-        let cb = match self.options.parse_callbacks {
-            Some(ref cb) => cb,
-            None => return CanDerive::No,
-        };
-
         *self
             .blocklisted_types_implement_traits
             .borrow_mut()
@@ -2255,8 +2257,27 @@ If you encounter an error missing from this list, please file an issue or a PR!"
             .or_insert_with(|| {
                 item.expect_type()
                     .name()
-                    .and_then(|name| {
-                        cb.blocklisted_type_implements_trait(name, derive_trait)
+                    .and_then(|name| match self.options.parse_callbacks {
+                        Some(ref cb) => cb.blocklisted_type_implements_trait(
+                            name,
+                            derive_trait,
+                        ),
+                        // Sized integer types from <stdint.h> get mapped to Rust primitive
+                        // types regardless of whether they are blocklisted, so ensure that
+                        // standard traits are considered derivable for them too.
+                        None => match name {
+                            "int8_t" | "uint8_t" | "int16_t" | "uint16_t" |
+                            "int32_t" | "uint32_t" | "int64_t" |
+                            "uint64_t" | "uintptr_t" | "intptr_t" |
+                            "ptrdiff_t" => Some(CanDerive::Yes),
+                            "size_t" if self.options.size_t_is_usize => {
+                                Some(CanDerive::Yes)
+                            }
+                            "ssize_t" if self.options.size_t_is_usize => {
+                                Some(CanDerive::Yes)
+                            }
+                            _ => Some(CanDerive::No),
+                        },
                     })
                     .unwrap_or(CanDerive::No)
             })

src/ir/item.rs

@@ -417,6 +417,8 @@ pub struct Item {
     parent_id: ItemId,
     /// The item kind.
     kind: ItemKind,
+    /// The source location of the item.
+    location: Option<clang::SourceLocation>,
 }
 
 impl AsRef<ItemId> for Item {
@@ -433,6 +435,7 @@ impl Item {
         annotations: Option<Annotations>,
         parent_id: ItemId,
         kind: ItemKind,
+        location: Option<clang::SourceLocation>,
     ) -> Self {
         debug_assert!(id != parent_id || kind.is_module());
         Item {
@@ -445,6 +448,7 @@ impl Item {
             comment,
             annotations: annotations.unwrap_or_default(),
             kind,
+            location,
         }
     }
 
@@ -454,10 +458,15 @@ impl Item {
         ty: &clang::Type,
         ctx: &mut BindgenContext,
     ) -> TypeId {
+        let location = ty.declaration().location();
         let ty = Opaque::from_clang_ty(ty, ctx);
         let kind = ItemKind::Type(ty);
         let parent = ctx.root_module().into();
-        ctx.add_item(Item::new(with_id, None, None, parent, kind), None, None);
+        ctx.add_item(
+            Item::new(with_id, None, None, parent, kind, Some(location)),
+            None,
+            None,
+        );
         with_id.as_type_id_unchecked()
     }
 
@@ -632,6 +641,17 @@ impl Item {
             return true;
         }
 
+        if !ctx.options().blocklisted_files.is_empty() {
+            if let Some(location) = &self.location {
+                let (file, _, _, _) = location.location();
+                if let Some(filename) = file.name() {
+                    if ctx.options().blocklisted_files.matches(&filename) {
+                        return true;
+                    }
+                }
+            }
+        }
+
         let path = self.path_for_allowlisting(ctx);
         let name = path[1..].join("::");
         ctx.options().blocklisted_items.matches(&name) ||
@@ -1297,7 +1317,7 @@ impl ClangItemParser for Item {
         let id = ctx.next_item_id();
         let module = ctx.root_module().into();
         ctx.add_item(
-            Item::new(id, None, None, module, ItemKind::Type(ty)),
+            Item::new(id, None, None, module, ItemKind::Type(ty), None),
             None,
             None,
         );
@@ -1335,6 +1355,7 @@ impl ClangItemParser for Item {
                                 annotations,
                                 relevant_parent_id,
                                 ItemKind::$what(item),
+                                Some(cursor.location()),
                             ),
                             declaration,
                             Some(cursor),
@@ -1516,6 +1537,7 @@ impl ClangItemParser for Item {
                 None,
                 parent_id.unwrap_or_else(|| current_module.into()),
                 ItemKind::Type(Type::new(None, None, kind, is_const)),
+                Some(location.location()),
             ),
             None,
             None,
@@ -1647,6 +1669,7 @@ impl ClangItemParser for Item {
                         annotations,
                         relevant_parent_id,
                         ItemKind::Type(item),
+                        Some(location.location()),
                     ),
                     declaration,
                     Some(location),
@@ -1875,6 +1898,7 @@ impl ClangItemParser for Item {
             None,
             parent,
             ItemKind::Type(Type::named(name)),
+            Some(location.location()),
         );
         ctx.add_type_param(item, definition);
         Some(id.as_type_id_unchecked())

src/lib.rs

@@ -308,6 +308,7 @@ impl Builder {
             (&self.options.blocklisted_types, "--blocklist-type"),
             (&self.options.blocklisted_functions, "--blocklist-function"),
             (&self.options.blocklisted_items, "--blocklist-item"),
+            (&self.options.blocklisted_files, "--blocklist-file"),
             (&self.options.opaque_types, "--opaque-type"),
             (&self.options.allowlisted_functions, "--allowlist-function"),
             (&self.options.allowlisted_types, "--allowlist-type"),
@@ -821,6 +822,13 @@ impl Builder {
         self
     }
 
+    /// Hide any contents of the given file from the generated bindings,
+    /// regardless of whether it's a type, function, module etc.
+    pub fn blocklist_file<T: AsRef<str>>(mut self, arg: T) -> Builder {
+        self.options.blocklisted_files.insert(arg);
+        self
+    }
+
     /// Treat the given type as opaque in the generated bindings. Regular
     /// expressions are supported.
     ///
@@ -1669,6 +1677,10 @@ struct BindgenOptions {
     /// blocklisted and should not appear in the generated code.
     blocklisted_items: RegexSet,
 
+    /// The set of files whose contents should be blocklisted and should not
+    /// appear in the generated code.
+    blocklisted_files: RegexSet,
+
     /// The set of types that should be treated as opaque structures in the
     /// generated code.
     opaque_types: RegexSet,
@@ -1982,6 +1994,7 @@ impl BindgenOptions {
             &mut self.blocklisted_types,
             &mut self.blocklisted_functions,
             &mut self.blocklisted_items,
+            &mut self.blocklisted_files,
             &mut self.opaque_types,
             &mut self.bitfield_enums,
             &mut self.constified_enums,
@@ -2029,6 +2042,7 @@ impl Default for BindgenOptions {
             blocklisted_types: Default::default(),
             blocklisted_functions: Default::default(),
             blocklisted_items: Default::default(),
+            blocklisted_files: Default::default(),
             opaque_types: Default::default(),
             rustfmt_path: Default::default(),
             depfile: Default::default(),

src/options.rs

@@ -164,6 +164,14 @@ where
                 .takes_value(true)
                 .multiple(true)
                 .number_of_values(1),
+            Arg::with_name("blocklist-file")
+                .alias("blacklist-file")
+                .long("blocklist-file")
+                .help("Mark all contents of <path> as hidden.")
+                .value_name("path")
+                .takes_value(true)
+                .multiple(true)
+                .number_of_values(1),
             Arg::with_name("no-layout-tests")
                 .long("no-layout-tests")
                 .help("Avoid generating layout tests for any type."),
@@ -630,6 +638,12 @@ where
         }
     }
 
+    if let Some(hidden_files) = matches.values_of("blocklist-file") {
+        for file in hidden_files {
+            builder = builder.blocklist_file(file);
+        }
+    }
+
     if matches.is_present("builtins") {
         builder = builder.emit_builtins();
     }