Merge #1082

1082: Add base for privacy visitor r=CohenArthur a=CohenArthur

This PR is extremely early and implements some building blocks for privacy visitors. I'd like to get some feedback on the architecture and, if satisfactory, merge this first "visitor" which only takes care of visiting HIR struct definitions, to make reviewing easier. We could also merge it to a different branch for now, in order to not add an incomplete pass to the compiler.

Thanks!

Co-authored-by: Arthur Cohen <[email protected]>

Author: bors[bot]

gcc/rust/Make-lang.in

@@ -89,6 +89,9 @@ GRS_OBJS = \
     rust/rust-ast-resolve-expr.o \
     rust/rust-ast-resolve-type.o \
     rust/rust-hir-type-check.o \
+    rust/rust-privacy-check.o \
+    rust/rust-privacy-ctx.o \
+    rust/rust-reachability.o \
     rust/rust-tyty.o \
     rust/rust-tyctx.o \
     rust/rust-tyty-bounds.o \
@@ -278,6 +281,7 @@ RUST_INCLUDES = -I $(srcdir)/rust \
 	-I $(srcdir)/rust/resolve \
 	-I $(srcdir)/rust/util \
 	-I $(srcdir)/rust/typecheck \
+	-I $(srcdir)/rust/privacy \
 	-I $(srcdir)/rust/lint
 
 # add files that require cross-folder includes - currently rust-lang.o, rust-lex.o
@@ -339,6 +343,11 @@ rust/%.o: rust/typecheck/%.cc
 	$(COMPILE) $(RUST_CXXFLAGS) $(RUST_INCLUDES) $<
 	$(POSTCOMPILE)
 
+# build rust/privacy files in rust folder
+rust/%.o: rust/privacy/%.cc
+	$(COMPILE) $(RUST_CXXFLAGS) $(RUST_INCLUDES) $<
+	$(POSTCOMPILE)
+
 # build rust/lint files in rust folder
 rust/%.o: rust/lint/%.cc
 	$(COMPILE) $(RUST_CXXFLAGS) $(RUST_INCLUDES) $<

gcc/rust/hir/tree/rust-hir-item.h

@@ -576,6 +576,9 @@ struct Visibility
   // Returns whether visibility is in an error state.
   bool is_error () const { return vis_type == ERROR; }
 
+  // Does the current visibility refer to a simple `pub <item>` entirely public
+  bool is_public () const { return vis_type == PUBLIC; }
+
   // Creates an error visibility.
   static Visibility create_error ()
   {
@@ -621,6 +624,8 @@ class VisItem : public Item
 public:
   using HIR::Stmt::accept_vis;
 
+  BaseKind get_hir_kind () override final { return VIS_ITEM; }
+
   /* Does the item have some kind of public visibility (non-default
    * visibility)? */
   bool has_visibility () const { return !visibility.is_error (); }
@@ -1458,6 +1463,8 @@ struct StructField
   Analysis::NodeMapping get_mappings () const { return mappings; }
 
   Location get_locus () { return locus; }
+
+  Visibility &get_visibility () { return visibility; }
 };
 
 // Rust struct declaration with true struct type HIR node
@@ -2744,7 +2751,7 @@ class ImplBlock : public VisItem
 };
 
 // Abstract base class for an item used inside an extern block
-class ExternalItem
+class ExternalItem : public Node
 {
   Analysis::NodeMapping mappings;
   AST::AttrVec outer_attrs;
@@ -2755,6 +2762,8 @@ class ExternalItem
 public:
   virtual ~ExternalItem () {}
 
+  BaseKind get_hir_kind () override final { return EXTERNAL; }
+
   // Returns whether item has outer attributes.
   bool has_outer_attrs () const { return !outer_attrs.empty (); }
 

gcc/rust/hir/tree/rust-hir.h

@@ -45,6 +45,41 @@ class HIRTypeVisitor;
 // forward decl for use in token tree method
 class Token;
 
+class Node
+{
+public:
+  // Kind for downcasting various HIR nodes to other base classes when visiting
+  // them
+  enum BaseKind
+  {
+    /* class ExternalItem */
+    EXTERNAL,
+    /* class TraitItem */
+    TRAIT_ITEM,
+    /* class VisItem */
+    VIS_ITEM,
+    /* class Item */
+    ITEM,
+    /* class ImplItem */
+    IMPL,
+    /* class Type */
+    TYPE,
+    /* class Stmt */
+    STMT,
+    /* class Expr */
+    EXPR,
+    /* class Pattern */
+    PATTERN,
+  };
+
+  /**
+   * Get the kind of HIR node we are dealing with. This is useful for
+   * downcasting to more precise types when necessary, i.e going from an `Item*`
+   * to a `VisItem*`
+   */
+  virtual BaseKind get_hir_kind () = 0;
+};
+
 // A literal - value with a type. Used in LiteralExpr and LiteralPattern.
 struct Literal
 {
@@ -91,7 +126,7 @@ struct Literal
 
 /* Base statement abstract class. Note that most "statements" are not allowed in
  * top-level module scope - only a subclass of statements called "items" are. */
-class Stmt
+class Stmt : public Node
 {
 public:
   // Unique pointer custom clone function
@@ -100,6 +135,8 @@ class Stmt
     return std::unique_ptr<Stmt> (clone_stmt_impl ());
   }
 
+  BaseKind get_hir_kind () override { return STMT; }
+
   virtual ~Stmt () {}
 
   virtual std::string as_string () const = 0;
@@ -138,6 +175,8 @@ class Item : public Stmt
     return std::unique_ptr<Item> (clone_item_impl ());
   }
 
+  BaseKind get_hir_kind () override { return ITEM; }
+
   std::string as_string () const override;
 
   /* Adds crate names to the vector passed by reference, if it can
@@ -171,7 +210,7 @@ class Item : public Stmt
 class ExprWithoutBlock;
 
 // Base expression HIR node - abstract
-class Expr
+class Expr : public Node
 {
   AST::AttrVec outer_attrs;
   Analysis::NodeMapping mappings;
@@ -213,6 +252,8 @@ class Expr
     Path,
   };
 
+  BaseKind get_hir_kind () override final { return EXPR; }
+
   const AST::AttrVec &get_outer_attrs () const { return outer_attrs; }
 
   // Unique pointer custom clone function
@@ -358,7 +399,7 @@ class IdentifierExpr : public ExprWithoutBlock
 };
 
 // Pattern base HIR node
-class Pattern
+class Pattern : public Node
 {
 public:
   enum PatternType
@@ -376,6 +417,8 @@ class Pattern
     SLICE,
   };
 
+  BaseKind get_hir_kind () override final { return PATTERN; }
+
   // Unique pointer custom clone function
   std::unique_ptr<Pattern> clone_pattern () const
   {
@@ -406,7 +449,7 @@ class Pattern
 class TraitBound;
 
 // Base class for types as represented in HIR - abstract
-class Type
+class Type : public Node
 {
 public:
   // Unique pointer custom clone function
@@ -418,6 +461,8 @@ class Type
   // virtual destructor
   virtual ~Type () {}
 
+  BaseKind get_hir_kind () override final { return TYPE; }
+
   virtual std::string as_string () const = 0;
 
   /* HACK: convert to trait bound. Virtual method overriden by classes that
@@ -686,7 +731,7 @@ class LifetimeParam : public GenericParam
 };
 
 // Item used in trait declarations - abstract base class
-class TraitItem
+class TraitItem : public Node
 {
 public:
   enum TraitItemKind
@@ -696,6 +741,8 @@ class TraitItem
     TYPE
   };
 
+  BaseKind get_hir_kind () override final { return TRAIT_ITEM; }
+
 protected:
   // Constructor
   TraitItem (Analysis::NodeMapping mappings) : mappings (mappings) {}
@@ -728,7 +775,7 @@ class TraitItem
   virtual const AST::AttrVec &get_outer_attrs () const = 0;
 };
 
-class ImplItem
+class ImplItem : public Node
 {
 public:
   enum ImplItemType
@@ -740,6 +787,8 @@ class ImplItem
 
   virtual ~ImplItem () {}
 
+  BaseKind get_hir_kind () override final { return IMPL; }
+
   // Unique pointer custom clone function
   std::unique_ptr<ImplItem> clone_inherent_impl_item () const
   {

gcc/rust/privacy/rust-privacy-check.cc

@@ -0,0 +1,49 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#include "rust-privacy-check.h"
+#include "rust-reachability.h"
+#include "rust-hir-type-check.h"
+
+extern bool
+saw_errors (void);
+
+namespace Rust {
+namespace Privacy {
+void
+Resolver::resolve (HIR::Crate &crate)
+{
+  PrivacyContext ctx;
+  auto ty_ctx = ::Rust::Resolver::TypeCheckContext::get ();
+  auto visitor = ReachabilityVisitor (ctx, *ty_ctx);
+
+  const auto &items = crate.items;
+  for (auto &item : items)
+    {
+      if (item->get_hir_kind () == HIR::Node::VIS_ITEM)
+	{
+	  auto vis_item = static_cast<HIR::VisItem *> (item.get ());
+	  vis_item->accept_vis (visitor);
+	}
+    }
+
+  if (saw_errors ())
+    return;
+}
+} // namespace Privacy
+} // namespace Rust

gcc/rust/privacy/rust-privacy-check.h

@@ -0,0 +1,45 @@
+// Copyright (C) 2020-2022 Free Software Foundation, Inc.
+
+// This file is part of GCC.
+
+// GCC is free software; you can redistribute it and/or modify it under
+// the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3, or (at your option) any later
+// version.
+
+// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+// for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with GCC; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+#ifndef RUST_PRIVACY_CHECK_H
+#define RUST_PRIVACY_CHECK_H
+
+#include "rust-hir-map.h"
+#include "rust-hir.h"
+#include "rust-hir-expr.h"
+#include "rust-hir-stmt.h"
+#include "rust-hir-item.h"
+#include "rust-hir-type-check.h"
+
+namespace Rust {
+namespace Privacy {
+class Resolver
+{
+public:
+  /**
+   * Perform the full privacy resolving pass on a crate.
+   *
+   * This resolver first computes the reachability of all items in a crate,
+   * before checking for privacy violations.
+   */
+  static void resolve (HIR::Crate &crate);
+};
+} // namespace Privacy
+} // namespace Rust
+
+#endif // !RUST_PRIVACY_CHECK_H