[PATCH 2/3] Refactor section name ref counting

[Strager Neds]

symtab_node::set_section_for_node manages the reference count of
section_hash_entry objects. I plan to add another function which needs
to manage the reference count of these objects. To avoid duplicating
code, factor the existing logic into reusable functions.

This patch should not change behavior.

Testing: Bootstrap on x86_64-linux-gnu with --disable-multilib
--enable-checking=release --enable-languages=c,c++. Observe no change in
test results.

2019-11-12  Matthew Glazar <strager....@gmail.com>

* gcc/symtab.c (symtab_node::set_section_for_node): Extract reference
counting logic into ...
(retain_section_hash_entry): ... here (new function) and ...
(release_section_hash_entry): ... here (new function).


diff --git a/gcc/symtab.c b/gcc/symtab.c
index 84d17c36189..a2aa519e760 100644
--- a/gcc/symtab.c
+++ b/gcc/symtab.c
@@ -368,6 +368,30 @@ section_name_hasher::equal (section_hash_entry
*n1, const char *name)
   return n1->name == name || !strcmp (n1->name, name);
 }

+static section_hash_entry *
+retain_section_hash_entry (section_hash_entry *entry)
+{
+  entry->ref_count++;
+  return entry;
+}
+
+static void
+release_section_hash_entry (section_hash_entry *entry)
+{
+  if (entry)
+    {
+      entry->ref_count--;
+      if (!entry->ref_count)
+    {
+      hashval_t hash = htab_hash_string (entry->name);
+      section_hash_entry **slot =
symtab->section_hash->find_slot_with_hash (entry->name,
+                                hash, INSERT);
+      ggc_free (entry);
+      symtab->section_hash->clear_slot (slot);
+    }
+    }
+}
+
 /* Add node into symbol table.  This function is not used directly, but via
    cgraph/varpool node creation routines.  */

@@ -1543,46 +1567,33 @@ void
 symtab_node::set_section_for_node (const char *section)
 {
   const char *current = get_section ();
-  section_hash_entry **slot;

   if (current == section
       || (current && section
       && !strcmp (current, section)))
     return;

-  if (current)
-    {
-      x_section->ref_count--;
-      if (!x_section->ref_count)
-    {
-      hashval_t hash = htab_hash_string (x_section->name);
-      slot = symtab->section_hash->find_slot_with_hash (x_section->name,
-                                hash, INSERT);
-      ggc_free (x_section);
-      symtab->section_hash->clear_slot (slot);
-    }
-      x_section = NULL;
-    }
+  release_section_hash_entry (x_section);
   if (!section)
     {
+      x_section = NULL;
       implicit_section = false;
       return;
     }
   if (!symtab->section_hash)
     symtab->section_hash = hash_table<section_name_hasher>::create_ggc (10);
-  slot = symtab->section_hash->find_slot_with_hash (section,
-                            htab_hash_string (section),
-                            INSERT);
+  section_hash_entry **slot = symtab->section_hash->find_slot_with_hash
+    (section, htab_hash_string (section), INSERT);
   if (*slot)
-    x_section = (section_hash_entry *)*slot;
+    x_section = retain_section_hash_entry (*slot);
   else
     {
       int len = strlen (section);
       *slot = x_section = ggc_cleared_alloc<section_hash_entry> ();
+      x_section->ref_count = 1;
       x_section->name = ggc_vec_alloc<char> (len + 1);
       memcpy (x_section->name, section, len + 1);
     }
-  x_section->ref_count++;
 }

 /* Worker for set_section.  */