[gcc r11-4900] Improve efficiency of copying section from another tree

[gcc r11-4900] Improve efficiency of copying section from another tree

[Jeff Law]

https://gcc.gnu.org/g:4656461585bfd0b925553995a9d114645f1287d0

commit r11-4900-g4656461585bfd0b925553995a9d114645f1287d0
Author: Strager Neds <strager.nds@gmail.com>
Date:   Tue Nov 10 20:57:04 2020 -0700

    Improve efficiency of copying section from another tree
    
    gcc/
            * cgraph.h (symtab_node::set_section_for_node): Declare new
            overload.
            (symtab_node::set_section_from_string): Rename from set_section.
            (symtab_node::set_section_from_node): Declare.
            * symtab.c (symtab_node::set_section_for_node): Define new
            overload.
            (symtab_node::set_section_from_string): Rename from set_section.
            (symtab_node::set_section_from_node): Define.
            (symtab_node::set_section): Call renamed set_section_from_string.
            (symtab_node::set_section): Call new set_section_from_node.

Diff:
---
 gcc/cgraph.h |  9 +++++++--
 gcc/symtab.c | 31 ++++++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/gcc/cgraph.h b/gcc/cgraph.h
index 2e62db2a33b..97287bda6f0 100644
--- a/gcc/cgraph.h
+++ b/gcc/cgraph.h
@@ -330,6 +330,10 @@ public:
      use set_section.  */
   void set_section_for_node (const char *section);
 
+  /* Like set_section_for_node, but copying the section name from another
+     node.  */
+  void set_section_for_node (const symtab_node &other);
+
   /* Set initialization priority to PRIORITY.  */
   void set_init_priority (priority_type priority);
 
@@ -646,8 +650,9 @@ protected:
 				      void *data,
 				      bool include_overwrite);
 private:
-  /* Worker for set_section.  */
-  static bool set_section (symtab_node *n, void *s);
+  /* Workers for set_section.  */
+  static bool set_section_from_string (symtab_node *n, void *s);
+  static bool set_section_from_node (symtab_node *n, void *o);
 
   /* Worker for symtab_resolve_alias.  */
   static bool set_implicit_section (symtab_node *n, void *);
diff --git a/gcc/symtab.c b/gcc/symtab.c
index c84259f1032..393d6b07870 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -1668,15 +1668,37 @@ symtab_node::set_section_for_node (const char *section)
     }
 }
 
-/* Worker for set_section.  */
+void
+symtab_node::set_section_for_node (const symtab_node &other)
+{
+  if (x_section == other.x_section)
+    return;
+  if (get_section () && other.get_section ())
+    gcc_checking_assert (strcmp (get_section (), other.get_section ()) != 0);
+  release_section_hash_entry (x_section);
+  if (other.x_section)
+    x_section = retain_section_hash_entry (other.x_section);
+  else
+    x_section = NULL;
+}
+
+/* Workers for set_section.  */
 
 bool
-symtab_node::set_section (symtab_node *n, void *s)
+symtab_node::set_section_from_string (symtab_node *n, void *s)
 {
   n->set_section_for_node ((char *)s);
   return false;
 }
 
+bool
+symtab_node::set_section_from_node (symtab_node *n, void *o)
+{
+  const symtab_node &other = *static_cast<const symtab_node *> (o);
+  n->set_section_for_node (other);
+  return false;
+}
+
 /* Set section of symbol and its aliases.  */
 
 void
@@ -1684,15 +1706,14 @@ symtab_node::set_section (const char *section)
 {
   gcc_assert (!this->alias || !this->analyzed);
   call_for_symbol_and_aliases
-    (symtab_node::set_section, const_cast<char *>(section), true);
+    (symtab_node::set_section_from_string, const_cast<char *>(section), true);
 }
 
 void
 symtab_node::set_section (const symtab_node &other)
 {
-  const char *section = other.get_section ();
   call_for_symbol_and_aliases
-    (symtab_node::set_section, const_cast<char *>(section), true);
+    (symtab_node::set_section_from_node, const_cast<symtab_node *>(&other), true);
 }
 
 /* Return the initialization priority.  */