hir: improve doc attribute handling ...

... should fix #1125

Signed-off-by: Zixing Liu <liushuyu011@gmail.com>

Author: liushuyu

gcc/rust/hir/rust-ast-lower-base.cc

@@ -838,7 +838,11 @@ ASTLoweringBase::handle_outer_attributes (const HIR::Item &item)
 			  && attr.get_attr_input ().get_attr_input_type ()
 			       == AST::AttrInput::AttrInputType::LITERAL;
 
-      if (is_lang_item)
+      bool is_doc_item = str_path.compare ("doc") == 0;
+
+      if (is_doc_item)
+	handle_doc_item_attribute (item, attr);
+      else if (is_lang_item)
 	handle_lang_item_attribute (item, attr);
       else if (!attribute_handled_in_another_pass (str_path))
 	{
@@ -848,6 +852,27 @@ ASTLoweringBase::handle_outer_attributes (const HIR::Item &item)
     }
 }
 
+void
+ASTLoweringBase::handle_doc_item_attribute (const HIR::Item &item,
+					    const AST::Attribute &attr)
+{
+  auto simple_doc_comment = attr.has_attr_input ()
+			    && attr.get_attr_input ().get_attr_input_type ()
+				 == AST::AttrInput::AttrInputType::LITERAL;
+  if (simple_doc_comment)
+    return;
+
+  const AST::AttrInput &input = attr.get_attr_input ();
+  bool is_token_tree
+    = input.get_attr_input_type () == AST::AttrInput::AttrInputType::TOKEN_TREE;
+  rust_assert (is_token_tree);
+  const auto &option = static_cast<const AST::DelimTokenTree &> (input);
+  AST::AttrInputMetaItemContainer *meta_item = option.parse_to_meta_item ();
+
+  // TODO: add actual and complete checks for the doc attributes
+  rust_assert (meta_item);
+}
+
 void
 ASTLoweringBase::handle_lang_item_attribute (const HIR::Item &item,
 					     const AST::Attribute &attr)

gcc/rust/hir/rust-ast-lower-base.h

@@ -268,6 +268,9 @@ class ASTLoweringBase : public AST::ASTVisitor
   void handle_lang_item_attribute (const HIR::Item &item,
 				   const AST::Attribute &attr);
 
+  void handle_doc_item_attribute (const HIR::Item &item,
+				  const AST::Attribute &attr);
+
   bool is_known_attribute (const std::string &attribute_path) const;
 
   bool

gcc/rust/util/rust-attributes.cc

@@ -21,11 +21,12 @@
 namespace Rust {
 namespace Analysis {
 
-// https://doc.rust-lang.org/stable/nightly-rustc/src/rustc_feature/builtin_attrs.rs.html#256
+// https://doc.rust-lang.org/stable/nightly-rustc/src/rustc_feature/builtin_attrs.rs.html#248
 static const BuiltinAttrDefinition __definitions[]
-  = {{"inline", CODE_GENERATION}, {"cfg", EXPANSION},
-     {"cfg_attr", EXPANSION},	  {"allow", STATIC_ANALYSIS},
-     {"lang", HIR_LOWERING},	  {"must_use", STATIC_ANALYSIS}};
+  = {{"inline", CODE_GENERATION},  {"cfg", EXPANSION},
+     {"cfg_attr", EXPANSION},	   {"allow", STATIC_ANALYSIS},
+     {"doc", HIR_LOWERING},	   {"lang", HIR_LOWERING},
+     {"must_use", STATIC_ANALYSIS}};
 
 BuiltinAttributeMappings *
 BuiltinAttributeMappings::get ()

gcc/testsuite/rust/compile/torture/doc_comment.rs

@@ -0,0 +1,16 @@
+/// doc comment 1
+/// doc comment 2
+/// `blah blah` markdown
+pub struct TestStruct {}
+
+#[doc(hidden)]
+pub struct DocAttribute {}
+
+#[doc(a,b)]
+pub struct UnkAttribute {}
+
+fn main() {
+    let _ = TestStruct {};
+    let _ = DocAttribute {};
+    let _ = UnkAttribute {};
+}