From 8c6ffb4c6f86231eee318ceeb8546a53037edfe9 Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 4 Oct 2022 23:13:15 +0200
Subject: [PATCH 128/157] [Backport][SME] attribs: Add overloads with namespace
 name

Reference: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=0764dc8537a4f87089ecd32391cb5f8803b43c96

I've discovered a problem with the way we handle scoped attributes.  For
declaration or type attributes for attributes we don't know anything about
we just don't add them to the declarations or types, so later in the FEs and
middle-end it is fine to use lookup_attribute etc.  which just check the
attribute name and not namespace because non-standard non-GNU attributes
just won't show there.  But in the case of attributes on statements, nothing
has filtered out the unknown attributes, so with my earlier assume
attribute patch e.g.  c-c++-common/Wno-attributes-6.c test failed because
it uses:
[[vendor::assume(1 + 1 == 2)]];
with -Wno-attributes=vendor::assume and lookup_attribute ("assume", )
finds such attribute and handled it that way.
So, for those cases, this patch introduces lookup_attribute and
remove_attribute overloads which specify also the namespace.
I think the fallthrough, hot, cold, likely, unlikely attribute handling
will need to use the new APIs too, so that we don't handle
msft::fallthrough attribute as something we'd know.

2022-10-04  Jakub Jelinek  <jakub@redhat.com>

	* attribs.h (remove_attribute): Declare overload with additional
	attr_ns argument.
	(private_lookup_attribute): Declare overload with additional
	attr_ns and attr_ns_len arguments.
	(lookup_attribute): New overload with additional attr_ns argument.
	* attribs.cc (remove_attribute): New overload with additional
	attr_ns argument.
	(private_lookup_attribute): New overload with additional
	attr_ns and attr_ns_len arguments.
---
 gcc/attribs.cc | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++
 gcc/attribs.h  | 38 ++++++++++++++++++++++++++++++
 2 files changed, 101 insertions(+)

diff --git a/gcc/attribs.cc b/gcc/attribs.cc
index 656ea739e..8e2696bc5 100644
--- a/gcc/attribs.cc
+++ b/gcc/attribs.cc
@@ -1598,6 +1598,36 @@ remove_attribute (const char *attr_name, tree list)
   return list;
 }
 
+/* Similarly but also match namespace on the removed attributes.  */
+
+tree
+remove_attribute (const char *attr_ns, const char *attr_name, tree list)
+{
+  tree *p;
+  gcc_checking_assert (attr_name[0] != '_');
+  gcc_checking_assert (attr_ns == NULL || attr_ns[0] != '_');
+
+  for (p = &list; *p;)
+    {
+      tree l = *p;
+
+      tree attr = get_attribute_name (l);
+      if (is_attribute_p (attr_name, attr))
+	{
+	  tree ns = get_attribute_namespace (l);
+	  if ((ns == NULL_TREE && attr_ns == NULL)
+	      || (ns && attr_ns && is_attribute_p (attr_ns, ns)))
+	    {
+	      *p = TREE_CHAIN (l);
+	      continue;
+	    }
+	}
+      p = &TREE_CHAIN (l);
+    }
+
+  return list;
+}
+
 /* Return an attribute list that is the union of a1 and a2.  */
 
 tree
@@ -1995,6 +2025,39 @@ private_lookup_attribute (const char *attr_name, size_t attr_len, tree list)
   return list;
 }
 
+/* Similarly but with also attribute namespace.  */
+
+tree
+private_lookup_attribute (const char *attr_ns, const char *attr_name,
+			  size_t attr_ns_len, size_t attr_len, tree list)
+{
+  while (list)
+    {
+      tree attr = get_attribute_name (list);
+      size_t ident_len = IDENTIFIER_LENGTH (attr);
+      if (cmp_attribs (attr_name, attr_len, IDENTIFIER_POINTER (attr),
+		       ident_len))
+	{
+	  tree ns = get_attribute_namespace (list);
+	  if (ns == NULL_TREE)
+	    {
+	      if (attr_ns == NULL)
+		break;
+	    }
+	  else if (attr_ns)
+	    {
+	      ident_len = IDENTIFIER_LENGTH (ns);
+	      if (cmp_attribs (attr_ns, attr_ns_len, IDENTIFIER_POINTER (ns),
+			       ident_len))
+		break;
+	    }
+	}
+      list = TREE_CHAIN (list);
+    }
+
+  return list;
+}
+
 /* Return true if the function decl or type NODE has been declared
    with attribute ANAME among attributes ATTRS.  */
 
diff --git a/gcc/attribs.h b/gcc/attribs.h
index 0856f98fb..9ad530fcb 100644
--- a/gcc/attribs.h
+++ b/gcc/attribs.h
@@ -88,6 +88,10 @@ extern tree merge_type_attributes (tree, tree);
 
 extern tree remove_attribute (const char *, tree);
 
+/* Similarly but also with specific attribute namespace.  */
+
+extern tree remove_attribute (const char *, const char *, tree);
+
 /* Given two attributes lists, return a list of their union.  */
 
 extern tree merge_attributes (tree, tree);
@@ -119,6 +123,10 @@ extern int attribute_list_contained (const_tree, const_tree);
    for size.  */
 extern tree private_lookup_attribute (const char *attr_name, size_t attr_len,
 				      tree list);
+extern tree private_lookup_attribute (const char *attr_ns,
+				      const char *attr_name,
+				      size_t attr_ns_len, size_t attr_len,
+				      tree list);
 
 extern unsigned decls_mismatched_attributes (tree, tree, tree,
 					     const char* const[],
@@ -215,6 +223,36 @@ lookup_attribute (const char *attr_name, tree list)
     }
 }
 
+/* Similar to lookup_attribute, but also match the attribute namespace.  */
+
+static inline tree
+lookup_attribute (const char *attr_ns, const char *attr_name, tree list)
+{
+  if (CHECKING_P && attr_name[0] != '_')
+    {
+      size_t attr_len = strlen (attr_name);
+      gcc_checking_assert (!canonicalize_attr_name (attr_name, attr_len));
+    }
+  if (CHECKING_P && attr_ns && attr_ns[0] != '_')
+    {
+      size_t attr_ns_len = strlen (attr_ns);
+      gcc_checking_assert (!canonicalize_attr_name (attr_ns, attr_ns_len));
+    }
+  /* In most cases, list is NULL_TREE.  */
+  if (list == NULL_TREE)
+    return NULL_TREE;
+  else
+    {
+      size_t attr_ns_len = attr_ns ? strlen (attr_ns) : 0;
+      size_t attr_len = strlen (attr_name);
+      /* Do the strlen() before calling the out-of-line implementation.
+	 In most cases attr_name is a string constant, and the compiler
+	 will optimize the strlen() away.  */
+      return private_lookup_attribute (attr_ns, attr_name,
+				       attr_ns_len, attr_len, list);
+    }
+}
+
 /* Given an attribute name ATTR_NAME and a list of attributes LIST,
    return a pointer to the attribute's list first element if the attribute
    starts with ATTR_NAME.  ATTR_NAME must be in the form 'text' (not
-- 
2.33.0