Use htab_up in abbrev_table

This changes abbrev_table to use an htab_up rather than an ad hoc,
bucket-based hash table.

2020-02-08  Tom Tromey  <tom@tromey.com>

	* dwarf2/abbrev.c (abbrev_table): Move constructor from header.
	Rewrite.
	(abbrev_table::add_abbrev, abbrev_table::lookup_abbrev): Rewrite.
	* dwarf2/abbrev.h (struct abbrev_info) <next>: Remove.
	(abbrev_table::abbrev_table): No longer inline.
	(ABBREV_HASH_SIZE): Remove.
	(abbrev_table::m_abbrevs): Now an htab_up.

Change-Id: Icbaa8e49501f9c43218d6a81a7e8c4d3a77d65dc

1 files changed, 3 insertions, 16 deletions

diff --git a/gdb/dwarf2/abbrev.h b/gdb/dwarf2/abbrev.h
index 52103b0..b9ace64 100644
--- a/gdb/dwarf2/abbrev.h
+++ b/gdb/dwarf2/abbrev.h
@@ -35,7 +35,6 @@ struct abbrev_info
     unsigned short has_children;		/* boolean */
     unsigned short num_attrs;	/* number of attributes */
     struct attr_abbrev *attrs;	/* an array of attribute descriptions */
-    struct abbrev_info *next;	/* next in chain */
   };
 
 struct attr_abbrev
@@ -47,9 +46,6 @@ struct attr_abbrev
     LONGEST implicit_const;
   };
 
-/* Size of abbrev_table.abbrev_hash_table.  */
-#define ABBREV_HASH_SIZE 121
-
 struct abbrev_table;
 typedef std::unique_ptr<struct abbrev_table> abbrev_table_up;
 
@@ -73,13 +69,7 @@ struct abbrev_table
 
 private:
 
-  explicit abbrev_table (sect_offset off)
-    : sect_off (off)
-  {
-    m_abbrevs =
-      XOBNEWVEC (&m_abbrev_obstack, struct abbrev_info *, ABBREV_HASH_SIZE);
-    memset (m_abbrevs, 0, ABBREV_HASH_SIZE * sizeof (struct abbrev_info *));
-  }
+  explicit abbrev_table (sect_offset off);
 
   DISABLE_COPY_AND_ASSIGN (abbrev_table);
 
@@ -90,11 +80,8 @@ private:
   /* Add an abbreviation to the table.  */
   void add_abbrev (unsigned int abbrev_number, struct abbrev_info *abbrev);
 
-  /* Hash table of abbrevs.
-     This is an array of size ABBREV_HASH_SIZE allocated in abbrev_obstack.
-     It could be statically allocated, but the previous code didn't so we
-     don't either.  */
-  struct abbrev_info **m_abbrevs;
+  /* Hash table of abbrevs.  */
+  htab_up m_abbrevs;
 
   /* Storage for the abbrev table.  */
   auto_obstack m_abbrev_obstack;