[gcc/devel/rust/master] privacy: visibility: Add base for ModuleVisibility resolver

[gcc/devel/rust/master] privacy: visibility: Add base for ModuleVisibility resolver

[Thomas Schwinge]

https://gcc.gnu.org/g:77afec780ae6193a5e4d3895d3169b150e4b556d

commit 77afec780ae6193a5e4d3895d3169b150e4b556d
Author: Arthur Cohen <arthur.cohen@embecosm.com>
Date:   Fri Apr 22 10:00:03 2022 +0200

    privacy: visibility: Add base for ModuleVisibility resolver

Diff:
---
 gcc/rust/Make-lang.in                        |   1 +
 gcc/rust/privacy/rust-privacy-check.cc       |   8 ++
 gcc/rust/privacy/rust-privacy-common.h       |   3 +
 gcc/rust/privacy/rust-reachability.h         |   2 +
 gcc/rust/privacy/rust-visibility-resolver.cc | 121 +++++++++++++++++++++++++++
 gcc/rust/privacy/rust-visibility-resolver.h  |  89 ++++++++++++++++++++
 6 files changed, 224 insertions(+)

diff --git a/gcc/rust/Make-lang.in b/gcc/rust/Make-lang.in
index 82a4d6bf3c6..d25f403fbfb 100644
--- a/gcc/rust/Make-lang.in
+++ b/gcc/rust/Make-lang.in
@@ -93,6 +93,7 @@ GRS_OBJS = \
     rust/rust-privacy-check.o \
     rust/rust-privacy-ctx.o \
     rust/rust-reachability.o \
+    rust/rust-visibility-resolver.o \
     rust/rust-tyty.o \
     rust/rust-tyctx.o \
     rust/rust-tyty-bounds.o \
diff --git a/gcc/rust/privacy/rust-privacy-check.cc b/gcc/rust/privacy/rust-privacy-check.cc
index ccef318ed11..ccfed2c1a0f 100644
--- a/gcc/rust/privacy/rust-privacy-check.cc
+++ b/gcc/rust/privacy/rust-privacy-check.cc
@@ -19,6 +19,8 @@
 #include "rust-privacy-check.h"
 #include "rust-reachability.h"
 #include "rust-hir-type-check.h"
+#include "rust-hir-map.h"
+#include "rust-visibility-resolver.h"
 
 extern bool
 saw_errors (void);
@@ -29,10 +31,16 @@ void
 Resolver::resolve (HIR::Crate &crate)
 {
   PrivacyContext ctx;
+  auto mappings = Analysis::Mappings::get ();
+
+  auto resolver = VisibilityResolver (*mappings);
+  resolver.go (crate);
+
   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)
diff --git a/gcc/rust/privacy/rust-privacy-common.h b/gcc/rust/privacy/rust-privacy-common.h
index 8f818fc3d5c..a94d3c80b4d 100644
--- a/gcc/rust/privacy/rust-privacy-common.h
+++ b/gcc/rust/privacy/rust-privacy-common.h
@@ -30,11 +30,14 @@ class ModuleVisibility
 public:
   enum Type
   {
+    Unknown,
     Private,
     Public,
     Restricted,
   };
 
+  ModuleVisibility () : kind (Unknown), module_id (UNKNOWN_DEFID) {}
+
   static ModuleVisibility create_restricted (DefId module_id)
   {
     return ModuleVisibility (Type::Restricted, module_id);
diff --git a/gcc/rust/privacy/rust-reachability.h b/gcc/rust/privacy/rust-reachability.h
index e61fbdfa8b3..e0bc4f5f0b8 100644
--- a/gcc/rust/privacy/rust-reachability.h
+++ b/gcc/rust/privacy/rust-reachability.h
@@ -46,6 +46,8 @@ public:
     : current_level (ReachLevel::Reachable), ctx (ctx), ty_ctx (ty_ctx)
   {}
 
+  // FIXME: Add `go` method which takes an `HIR::Crate &` as argument
+
   /**
    * Visit all the predicates of all the generic types of a given item, marking
    * them as reachable or not.
diff --git a/gcc/rust/privacy/rust-visibility-resolver.cc b/gcc/rust/privacy/rust-visibility-resolver.cc
new file mode 100644
index 00000000000..2ca3bd75174
--- /dev/null
+++ b/gcc/rust/privacy/rust-visibility-resolver.cc
@@ -0,0 +1,121 @@
+// 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-visibility-resolver.h"
+#include "rust-hir.h"
+#include "rust-hir-item.h"
+
+namespace Rust {
+namespace Privacy {
+
+VisibilityResolver::VisibilityResolver (Analysis::Mappings &mappings)
+  : mappings (mappings)
+{
+  // FIXME: Insert a top module (crate) inside the module_stack
+  // FIXME: Insert the visibility of the crate in the mappings maybe?
+}
+
+void
+VisibilityResolver::go (HIR::Crate &crate)
+{
+  for (auto &item : crate.items)
+    {
+      if (item->get_hir_kind () == HIR::Node::VIS_ITEM)
+	{
+	  auto vis_item = static_cast<HIR::VisItem *> (item.get ());
+	  vis_item->accept_vis (*this);
+	}
+    }
+}
+
+bool
+VisibilityResolver::resolve_visibility (const HIR::Visibility &visibility,
+					ModuleVisibility &to_resolve)
+{
+  return false;
+}
+
+DefId
+VisibilityResolver::peek_module ()
+{
+  // We're always inserting a top module - the crate
+  // But we have to check otherwise `.back()` is UB
+  if (module_stack.empty ())
+    gcc_unreachable ();
+
+  return module_stack.back ();
+}
+
+void
+VisibilityResolver::visit (HIR::Module &mod)
+{}
+
+void
+VisibilityResolver::visit (HIR::ExternCrate &crate)
+{}
+
+void
+VisibilityResolver::visit (HIR::UseDeclaration &use_decl)
+{}
+
+void
+VisibilityResolver::visit (HIR::Function &func)
+{}
+
+void
+VisibilityResolver::visit (HIR::TypeAlias &type_alias)
+{}
+
+void
+VisibilityResolver::visit (HIR::StructStruct &struct_item)
+{}
+
+void
+VisibilityResolver::visit (HIR::TupleStruct &tuple_struct)
+{}
+
+void
+VisibilityResolver::visit (HIR::Enum &enum_item)
+{}
+
+void
+VisibilityResolver::visit (HIR::Union &union_item)
+{}
+
+void
+VisibilityResolver::visit (HIR::ConstantItem &const_item)
+{}
+
+void
+VisibilityResolver::visit (HIR::StaticItem &static_item)
+{}
+
+void
+VisibilityResolver::visit (HIR::Trait &trait)
+{}
+
+void
+VisibilityResolver::visit (HIR::ImplBlock &impl)
+{}
+
+void
+VisibilityResolver::visit (HIR::ExternBlock &block)
+{}
+
+} // namespace Privacy
+} // namespace Rust
diff --git a/gcc/rust/privacy/rust-visibility-resolver.h b/gcc/rust/privacy/rust-visibility-resolver.h
new file mode 100644
index 00000000000..394c3d4c414
--- /dev/null
+++ b/gcc/rust/privacy/rust-visibility-resolver.h
@@ -0,0 +1,89 @@
+// 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_VISIBILITY_H
+#define RUST_VISIBILITY_H
+
+#include "rust-hir.h"
+#include "rust-hir-expr.h"
+#include "rust-hir-stmt.h"
+#include "rust-hir-item.h"
+#include "rust-hir-map.h"
+#include "rust-hir-visitor.h"
+
+namespace Rust {
+namespace Privacy {
+
+class VisibilityResolver : public HIR::HIRVisItemVisitor
+{
+public:
+  VisibilityResolver (Analysis::Mappings &mappings);
+
+  /**
+   * Perform visibility resolving on an entire crate
+   */
+  void go (HIR::Crate &crate);
+
+  /**
+   * Resolve the visibility of an item to its ModuleVisibility. This function
+   * emits errors if necessary. The contents of the to_resolve parameter will be
+   * overwritten on success.
+   *
+   * @param visibility Visibility of the item to resolve
+   * @param to_resolve ModuleVisibility reference to fill on success.
+   *
+   * @return false on error, true if the resolving was successful.
+   */
+  bool resolve_visibility (const HIR::Visibility &visibility,
+			   ModuleVisibility &to_resolve);
+
+  /**
+   * Get the DefId of the parent module we are currently visiting.
+   *
+   * @return UNKNOWN_DEFID if the module stack is empty, a valid `DefId`
+   * otherwise
+   */
+  DefId peek_module ();
+
+  virtual void visit (HIR::Module &mod);
+  virtual void visit (HIR::ExternCrate &crate);
+  virtual void visit (HIR::UseDeclaration &use_decl);
+  virtual void visit (HIR::Function &func);
+  virtual void visit (HIR::TypeAlias &type_alias);
+  virtual void visit (HIR::StructStruct &struct_item);
+  virtual void visit (HIR::TupleStruct &tuple_struct);
+  virtual void visit (HIR::Enum &enum_item);
+  virtual void visit (HIR::Union &union_item);
+  virtual void visit (HIR::ConstantItem &const_item);
+  virtual void visit (HIR::StaticItem &static_item);
+  virtual void visit (HIR::Trait &trait);
+  virtual void visit (HIR::ImplBlock &impl);
+  virtual void visit (HIR::ExternBlock &block);
+
+private:
+  /* Mappings to insert visibilities into */
+  Analysis::Mappings &mappings;
+
+  /* Stack of modules visited by this visitor */
+  std::vector<DefId> module_stack;
+};
+
+} // namespace Privacy
+} // namespace Rust
+
+#endif // !RUST_VISIBILITY_H