[gcc r14-7850] gccrs: Check proc_macro attributes on non root functions

[gcc r14-7850] gccrs: Check proc_macro attributes on non root functions

[Arthur Cohen]

https://gcc.gnu.org/g:b05d874fc527f81c54b50e62f204eb8cd04250d8

commit r14-7850-gb05d874fc527f81c54b50e62f204eb8cd04250d8
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Wed Jul 26 12:16:12 2023 +0200

    gccrs: Check proc_macro attributes on non root functions
    
    Check proc_macro, proc_macro_attribute and proc_macro_derive attributes
    on non root functions, emit an error when one is found.
    
    gcc/rust/ChangeLog:
    
            * util/rust-attributes.cc (check_proc_macro_non_root): Add
            function to emit this specific error.
            (AttributeChecker::visit): Modify visitor to propagate to some
            containers that were not handled correctly.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/util/rust-attributes.cc | 56 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 50 insertions(+), 6 deletions(-)

diff --git a/gcc/rust/util/rust-attributes.cc b/gcc/rust/util/rust-attributes.cc
index a39c843bc1d..8b133cc7e7d 100644
--- a/gcc/rust/util/rust-attributes.cc
+++ b/gcc/rust/util/rust-attributes.cc
@@ -225,6 +225,24 @@ check_proc_macro_non_function (const AST::AttrVec &attributes)
     }
 }
 
+// Emit an error when one attribute is either proc_macro, proc_macro_attribute
+// or proc_macro_derive
+static void
+check_proc_macro_non_root (AST::AttrVec attributes, location_t loc)
+{
+  for (auto &attr : attributes)
+    {
+      if (is_proc_macro_type (attr))
+	{
+	  rust_error_at (
+	    loc,
+	    "functions tagged with %<#[%s]%> must currently "
+	    "reside in the root of the crate",
+	    attr.get_path ().get_segments ().at (0).as_string ().c_str ());
+	}
+    }
+}
+
 void
 AttributeChecker::check_attribute (const AST::Attribute &attribute)
 {
@@ -435,8 +453,20 @@ AttributeChecker::visit (AST::ClosureExprInner &)
 {}
 
 void
-AttributeChecker::visit (AST::BlockExpr &)
-{}
+AttributeChecker::visit (AST::BlockExpr &expr)
+{
+  for (auto &stmt : expr.get_statements ())
+    {
+      if (stmt->get_stmt_kind () == AST::Stmt::Kind::Item)
+	{
+	  // Non owning pointer, let it go out of scope
+	  auto item = static_cast<AST::Item *> (stmt.get ());
+	  check_proc_macro_non_root (item->get_outer_attrs (),
+				     item->get_locus ());
+	}
+      stmt->accept_vis (*this);
+    }
+}
 
 void
 AttributeChecker::visit (AST::ClosureExprInnerTyped &)
@@ -479,8 +509,10 @@ AttributeChecker::visit (AST::ReturnExpr &)
 {}
 
 void
-AttributeChecker::visit (AST::UnsafeBlockExpr &)
-{}
+AttributeChecker::visit (AST::UnsafeBlockExpr &expr)
+{
+  expr.get_block_expr ()->accept_vis (*this);
+}
 
 void
 AttributeChecker::visit (AST::LoopExpr &)
@@ -540,13 +572,20 @@ AttributeChecker::visit (AST::TypeBoundWhereClauseItem &)
 {}
 
 void
-AttributeChecker::visit (AST::Method &)
-{}
+AttributeChecker::visit (AST::Method &method)
+{
+  method.get_definition ()->accept_vis (*this);
+}
 
 void
 AttributeChecker::visit (AST::Module &module)
 {
   check_proc_macro_non_function (module.get_outer_attrs ());
+  for (auto &item : module.get_items ())
+    {
+      check_proc_macro_non_root (item->get_outer_attrs (), item->get_locus ());
+      item->accept_vis (*this);
+    }
 }
 
 void
@@ -611,6 +650,7 @@ AttributeChecker::visit (AST::Function &fun)
 	  check_crate_type (name, attribute);
 	}
     }
+  fun.get_definition ()->accept_vis (*this);
 }
 
 void
@@ -698,12 +738,16 @@ void
 AttributeChecker::visit (AST::InherentImpl &impl)
 {
   check_proc_macro_non_function (impl.get_outer_attrs ());
+  for (auto &item : impl.get_impl_items ())
+    item->accept_vis (*this);
 }
 
 void
 AttributeChecker::visit (AST::TraitImpl &impl)
 {
   check_proc_macro_non_function (impl.get_outer_attrs ());
+  for (auto &item : impl.get_impl_items ())
+    item->accept_vis (*this);
 }
 
 void