4 files changed, 298 insertions, 141 deletions

diff --git a/gcc/rust/ast/rust-ast-fragment.cc b/gcc/rust/ast/rust-ast-fragment.cc
new file mode 100644
index 0000000..c491609
--- /dev/null
+++ b/gcc/rust/ast/rust-ast-fragment.cc
@@ -0,0 +1,171 @@
+// 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-ast-fragment.h"
+
+namespace Rust {
+namespace AST {
+
+Fragment::Fragment (FragmentKind kind, std::vector<SingleASTNode> nodes)
+  : kind (kind), nodes (std::move (nodes))
+{}
+
+Fragment::Fragment (Fragment const &other) : kind (other.get_kind ())
+{
+  *this = other;
+}
+
+Fragment &
+Fragment::operator= (Fragment const &other)
+{
+  nodes.clear ();
+  nodes.reserve (other.nodes.size ());
+  kind = other.get_kind ();
+  for (auto &n : other.nodes)
+    {
+      nodes.push_back (n);
+    }
+
+  return *this;
+}
+
+Fragment
+Fragment::create_error ()
+{
+  return Fragment (FragmentKind::Error, {});
+}
+
+Fragment
+Fragment::complete (std::vector<AST::SingleASTNode> nodes)
+{
+  return Fragment (FragmentKind::Complete, std::move (nodes));
+}
+
+Fragment
+Fragment::unexpanded ()
+{
+  return Fragment (FragmentKind::Unexpanded, {});
+}
+
+std::vector<SingleASTNode> &
+Fragment::get_nodes ()
+{
+  return nodes;
+}
+
+FragmentKind
+Fragment::get_kind () const
+{
+  return kind;
+}
+
+bool
+Fragment::is_error () const
+{
+  return get_kind () == FragmentKind::Error;
+}
+
+bool
+Fragment::should_expand () const
+{
+  return !is_error ();
+}
+
+bool
+Fragment::is_expression_fragment () const
+{
+  return is_single_fragment_of_kind (SingleASTNode::NodeType::EXPRESSION);
+}
+
+bool
+Fragment::is_type_fragment () const
+{
+  return is_single_fragment_of_kind (SingleASTNode::NodeType::TYPE);
+}
+
+std::unique_ptr<Expr>
+Fragment::take_expression_fragment ()
+{
+  assert_single_fragment (SingleASTNode::NodeType::EXPRESSION);
+  return nodes[0].take_expr ();
+}
+
+std::unique_ptr<Type>
+Fragment::take_type_fragment ()
+{
+  assert_single_fragment (SingleASTNode::NodeType::TYPE);
+  return nodes[0].take_type ();
+}
+
+void
+Fragment::accept_vis (ASTVisitor &vis)
+{
+  for (auto &node : nodes)
+    node.accept_vis (vis);
+}
+
+bool
+Fragment::is_single_fragment () const
+{
+  return nodes.size () == 1;
+}
+
+bool
+Fragment::is_single_fragment_of_kind (SingleASTNode::NodeType expected) const
+{
+  return is_single_fragment () && nodes[0].get_kind () == expected;
+}
+
+void
+Fragment::assert_single_fragment (SingleASTNode::NodeType expected) const
+{
+  static const std::map<SingleASTNode::NodeType, const char *> str_map = {
+    {SingleASTNode::NodeType::IMPL, "impl"},
+    {SingleASTNode::NodeType::ITEM, "item"},
+    {SingleASTNode::NodeType::TYPE, "type"},
+    {SingleASTNode::NodeType::EXPRESSION, "expr"},
+    {SingleASTNode::NodeType::STMT, "stmt"},
+    {SingleASTNode::NodeType::EXTERN, "extern"},
+    {SingleASTNode::NodeType::TRAIT, "trait"},
+    {SingleASTNode::NodeType::TRAIT_IMPL, "trait impl"},
+  };
+
+  auto actual = nodes[0].get_kind ();
+  auto fail = false;
+
+  if (!is_single_fragment ())
+    {
+      rust_error_at (Location (), "fragment is not single");
+      fail = true;
+    }
+
+  if (actual != expected)
+    {
+      rust_error_at (
+	Location (),
+	"invalid fragment operation: expected %qs node, got %qs node",
+	str_map.find (expected)->second,
+	str_map.find (nodes[0].get_kind ())->second);
+      fail = true;
+    }
+
+  rust_assert (!fail);
+}
+
+} // namespace AST
+} // namespace Rust
diff --git a/gcc/rust/ast/rust-ast-fragment.h b/gcc/rust/ast/rust-ast-fragment.h
new file mode 100644
index 0000000..3ef4ba1
--- /dev/null
+++ b/gcc/rust/ast/rust-ast-fragment.h
@@ -0,0 +1,118 @@
+// 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_AST_FRAGMENT_H
+#define RUST_AST_FRAGMENT_H
+
+#include "rust-ast.h"
+#include "rust-system.h"
+
+namespace Rust {
+namespace AST {
+
+enum class FragmentKind
+{
+  /**
+   * If an AST Fragment still contains unexpanded tokens - this should only be
+   * used in the case of builtin macros which need to be expanded eagerly.
+   */
+  Unexpanded,
+  /**
+   * A completely expanded AST Fragment. This signifies that all
+   * `SingleASTNode`s in the `nodes` vector are valid.
+   *
+   * Note that this doesn't imply that the expansion is "done". One of the
+   * expanded nodes could very well be another macro invocation
+   */
+  Complete,
+  /**
+   * An error fragment.
+   */
+  Error,
+};
+
+/**
+ * An AST Fragment. Previously named `ASTFragment`.
+ *
+ * Basically, a "fragment" that can be incorporated into the AST, created as
+ * a result of macro expansion. Really annoying to work with due to the fact
+ * that macros can really expand to anything. As such, horrible representation
+ * at the moment.
+ */
+class Fragment
+{
+public:
+  Fragment (Fragment const &other);
+  Fragment &operator= (Fragment const &other);
+
+  /**
+   * Create an error fragment
+   */
+  static Fragment create_error ();
+
+  /**
+   * Create a complete AST fragment
+   */
+  static Fragment complete (std::vector<AST::SingleASTNode> nodes);
+
+  /**
+   * Create a fragment which contains unexpanded nodes
+   */
+  static Fragment unexpanded ();
+
+  FragmentKind get_kind () const;
+  std::vector<SingleASTNode> &get_nodes ();
+
+  bool is_error () const;
+  bool should_expand () const;
+
+  bool is_expression_fragment () const;
+  bool is_type_fragment () const;
+
+  std::unique_ptr<Expr> take_expression_fragment ();
+  std::unique_ptr<Type> take_type_fragment ();
+
+  void accept_vis (ASTVisitor &vis);
+
+private:
+  Fragment (FragmentKind kind, std::vector<SingleASTNode> nodes);
+
+  FragmentKind kind;
+
+  /**
+   * Basic idea: essentially, a vector of tagged unions of different AST node
+   * types. Now, this could actually be stored without a tagged union if the
+   * different AST node types had a unified parent, but that would create
+   * issues with the diamond problem or significant performance penalties. So
+   * a tagged union had to be used instead. A vector is used to represent the
+   * ability for a macro to expand to two statements, for instance.
+   */
+  std::vector<SingleASTNode> nodes;
+
+  /**
+   * We need to make a special case for Expression and Type fragments as only
+   * one Node will be extracted from the `nodes` vector
+   */
+  bool is_single_fragment () const;
+  bool is_single_fragment_of_kind (SingleASTNode::NodeType expected) const;
+  void assert_single_fragment (SingleASTNode::NodeType expected) const;
+};
+} // namespace AST
+} // namespace Rust
+
+#endif // !RUST_AST_FRAGMENT_H
diff --git a/gcc/rust/ast/rust-ast.h b/gcc/rust/ast/rust-ast.h
index 492faea..e0e10dc 100644
--- a/gcc/rust/ast/rust-ast.h
+++ b/gcc/rust/ast/rust-ast.h
@@ -1858,138 +1858,6 @@ public:
   }
 };
 
-/* Basically, a "fragment" that can be incorporated into the AST, created as
- * a result of macro expansion. Really annoying to work with due to the fact
- * that macros can really expand to anything. As such, horrible representation
- * at the moment. */
-class ASTFragment
-{
-private:
-  /* basic idea: essentially, a vector of tagged unions of different AST node
-   * types. Now, this could actually be stored without a tagged union if the
-   * different AST node types had a unified parent, but that would create
-   * issues with the diamond problem or significant performance penalties. So
-   * a tagged union had to be used instead. A vector is used to represent the
-   * ability for a macro to expand to two statements, for instance. */
-
-  std::vector<SingleASTNode> nodes;
-  bool fragment_is_error;
-
-  /**
-   * We need to make a special case for Expression and Type fragments as only
-   * one Node will be extracted from the `nodes` vector
-   */
-
-  bool is_single_fragment () const { return nodes.size () == 1; }
-
-  bool is_single_fragment_of_kind (SingleASTNode::NodeType expected) const
-  {
-    return is_single_fragment () && nodes[0].get_kind () == expected;
-  }
-
-  void assert_single_fragment (SingleASTNode::NodeType expected) const
-  {
-    static const std::map<SingleASTNode::NodeType, const char *> str_map = {
-      {SingleASTNode::NodeType::IMPL, "impl"},
-      {SingleASTNode::NodeType::ITEM, "item"},
-      {SingleASTNode::NodeType::TYPE, "type"},
-      {SingleASTNode::NodeType::EXPRESSION, "expr"},
-      {SingleASTNode::NodeType::STMT, "stmt"},
-      {SingleASTNode::NodeType::EXTERN, "extern"},
-      {SingleASTNode::NodeType::TRAIT, "trait"},
-      {SingleASTNode::NodeType::TRAIT_IMPL, "trait impl"},
-    };
-
-    auto actual = nodes[0].get_kind ();
-    auto fail = false;
-
-    if (!is_single_fragment ())
-      {
-	rust_error_at (Location (), "fragment is not single");
-	fail = true;
-      }
-
-    if (actual != expected)
-      {
-	rust_error_at (
-	  Location (),
-	  "invalid fragment operation: expected %qs node, got %qs node",
-	  str_map.find (expected)->second,
-	  str_map.find (nodes[0].get_kind ())->second);
-	fail = true;
-      }
-
-    rust_assert (!fail);
-  }
-
-public:
-  ASTFragment (std::vector<SingleASTNode> nodes, bool fragment_is_error = false)
-    : nodes (std::move (nodes)), fragment_is_error (fragment_is_error)
-  {
-    if (fragment_is_error)
-      rust_assert (nodes.empty ());
-  }
-
-  ASTFragment (ASTFragment const &other)
-    : fragment_is_error (other.fragment_is_error)
-  {
-    nodes.clear ();
-    nodes.reserve (other.nodes.size ());
-    for (auto &n : other.nodes)
-      {
-	nodes.push_back (n);
-      }
-  }
-
-  ASTFragment &operator= (ASTFragment const &other)
-  {
-    fragment_is_error = other.fragment_is_error;
-    nodes.clear ();
-    nodes.reserve (other.nodes.size ());
-    for (auto &n : other.nodes)
-      {
-	nodes.push_back (n);
-      }
-
-    return *this;
-  }
-
-  static ASTFragment create_error () { return ASTFragment ({}, true); }
-
-  std::vector<SingleASTNode> &get_nodes () { return nodes; }
-  bool is_error () const { return fragment_is_error; }
-
-  bool should_expand () const { return !is_error (); }
-
-  bool is_expression_fragment () const
-  {
-    return is_single_fragment_of_kind (SingleASTNode::NodeType::EXPRESSION);
-  }
-
-  bool is_type_fragment () const
-  {
-    return is_single_fragment_of_kind (SingleASTNode::NodeType::TYPE);
-  }
-
-  std::unique_ptr<Expr> take_expression_fragment ()
-  {
-    assert_single_fragment (SingleASTNode::NodeType::EXPRESSION);
-    return nodes[0].take_expr ();
-  }
-
-  std::unique_ptr<Type> take_type_fragment ()
-  {
-    assert_single_fragment (SingleASTNode::NodeType::TYPE);
-    return nodes[0].take_type ();
-  }
-
-  void accept_vis (ASTVisitor &vis)
-  {
-    for (auto &node : nodes)
-      node.accept_vis (vis);
-  }
-};
-
 // A crate AST object - holds all the data for a single compilation unit
 struct Crate
 {
diff --git a/gcc/rust/ast/rust-macro.h b/gcc/rust/ast/rust-macro.h
index 276f441..a02c216 100644
--- a/gcc/rust/ast/rust-macro.h
+++ b/gcc/rust/ast/rust-macro.h
@@ -20,6 +20,7 @@
 #define RUST_AST_MACRO_H
 
 #include "rust-ast.h"
+#include "rust-ast-fragment.h"
 #include "rust-location.h"
 #include <string>
 
@@ -456,8 +457,7 @@ class MacroRulesDefinition : public MacroItem
   std::vector<MacroRule> rules; // inlined form
   Location locus;
 
-  std::function<ASTFragment (Location, MacroInvocData &)>
-    associated_transcriber;
+  std::function<Fragment (Location, MacroInvocData &)> associated_transcriber;
   // Since we can't compare std::functions, we need to use an extra boolean
   bool is_builtin_rule;
 
@@ -468,10 +468,10 @@ class MacroRulesDefinition : public MacroItem
    * should make use of the actual rules. If the macro is builtin, then another
    * associated transcriber should be used
    */
-  static ASTFragment dummy_builtin (Location, MacroInvocData &)
+  static Fragment dummy_builtin (Location, MacroInvocData &)
   {
     gcc_unreachable ();
-    return ASTFragment::create_error ();
+    return Fragment::create_error ();
   }
 
   /* NOTE: in rustc, macro definitions are considered (and parsed as) a type
@@ -491,9 +491,9 @@ public:
       associated_transcriber (dummy_builtin), is_builtin_rule (false)
   {}
 
-  MacroRulesDefinition (Identifier builtin_name, DelimType delim_type,
-			std::function<ASTFragment (Location, MacroInvocData &)>
-			  associated_transcriber)
+  MacroRulesDefinition (
+    Identifier builtin_name, DelimType delim_type,
+    std::function<Fragment (Location, MacroInvocData &)> associated_transcriber)
     : outer_attrs (std::vector<Attribute> ()), rule_name (builtin_name),
       delim_type (delim_type), rules (std::vector<MacroRule> ()),
       locus (Location ()), associated_transcriber (associated_transcriber),
@@ -521,14 +521,14 @@ public:
   const std::vector<MacroRule> &get_rules () const { return rules; }
 
   bool is_builtin () const { return is_builtin_rule; }
-  const std::function<ASTFragment (Location, MacroInvocData &)> &
+  const std::function<Fragment (Location, MacroInvocData &)> &
   get_builtin_transcriber () const
   {
     rust_assert (is_builtin ());
     return associated_transcriber;
   }
   void set_builtin_transcriber (
-    std::function<ASTFragment (Location, MacroInvocData &)> transcriber)
+    std::function<Fragment (Location, MacroInvocData &)> transcriber)
   {
     associated_transcriber = transcriber;
     is_builtin_rule = true;