From: H.J. Lu <hongjiu.lu@intel.com>
Date: Mon, 17 Dec 2018 13:49:16 +0000 (+0000)
Subject: DWARF: Don't expand hash table when no insertion is needed
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=dc6b21cb4f3fbfbe83d1ca1270ebefb974efa7fa;p=gcc.git

DWARF: Don't expand hash table when no insertion is needed

dwarf2out_finish performs:

1. save_macinfo_strings
2. hash table traverse of index_string
3. output_macinfo -> output_macinfo_op
4. output_indirect_strings -> hash table traverse of output_index_string

find_slot_with_hash has

 if (insert == INSERT && m_size * 3 <= m_n_elements * 4)
    expand ();

which may expand hash table even if no insertion is neeed and change hash
table traverse order.  When output_macinfo_op is called, all index strings
have been added to hash table by save_macinfo_strings and we shouldn't
expand index string hash table.  Otherwise find_slot_with_hash will expand
hash table when hash table has the right size and hash table traverse of
output_index_string will have a different traverse order from index_string.

	PR debug/79342
	* dwarf2out.c (find_AT_string_in_table): Add insert argument
	defaulting to INSERT and replace INSERT.
	(find_AT_string): Likewise.
	(output_macinfo_op): Pass NO_INSERT to find_AT_string.

From-SVN: r267202
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 17b32f52c8f..9725e49b6a6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2018-12-17  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR debug/79342
+	* dwarf2out.c (find_AT_string_in_table): Add insert argument
+	defaulting to INSERT and replace INSERT.
+	(find_AT_string): Likewise.
+	(output_macinfo_op): Pass NO_INSERT to find_AT_string.
+
 2018-12-15  Jan Hubicka  <hubicka@ucw.cz>
 
 	* coverage.c (struct conts_entry): Add n_counts.
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index b2381056991..24e2d97d1e7 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -4618,12 +4618,13 @@ indirect_string_hasher::equal (indirect_string_node *x1, const char *x2)
 
 static struct indirect_string_node *
 find_AT_string_in_table (const char *str,
-			 hash_table<indirect_string_hasher> *table)
+			 hash_table<indirect_string_hasher> *table,
+			 enum insert_option insert = INSERT)
 {
   struct indirect_string_node *node;
 
   indirect_string_node **slot
-    = table->find_slot_with_hash (str, htab_hash_string (str), INSERT);
+    = table->find_slot_with_hash (str, htab_hash_string (str), insert);
   if (*slot == NULL)
     {
       node = ggc_cleared_alloc<indirect_string_node> ();
@@ -4640,12 +4641,12 @@ find_AT_string_in_table (const char *str,
 /* Add STR to the indirect string hash table.  */
 
 static struct indirect_string_node *
-find_AT_string (const char *str)
+find_AT_string (const char *str, enum insert_option insert = INSERT)
 {
   if (! debug_str_hash)
     debug_str_hash = hash_table<indirect_string_hasher>::create_ggc (10);
 
-  return find_AT_string_in_table (str, debug_str_hash);
+  return find_AT_string_in_table (str, debug_str_hash, insert);
 }
 
 /* Add a string attribute value to a DIE.  */
@@ -28095,7 +28096,19 @@ output_macinfo_op (macinfo_entry *ref)
       break;
     case DW_MACRO_define_strp:
     case DW_MACRO_undef_strp:
-      node = find_AT_string (ref->info);
+      /* NB: dwarf2out_finish performs:
+	   1. save_macinfo_strings
+	   2. hash table traverse of index_string
+	   3. output_macinfo -> output_macinfo_op
+	   4. output_indirect_strings
+		-> hash table traverse of output_index_string
+
+	 When output_macinfo_op is called, all index strings have been
+	 added to hash table by save_macinfo_strings and we can't pass
+	 INSERT to find_slot_with_hash which may expand hash table, even
+	 if no insertion is needed, and change hash table traverse order
+	 between index_string and output_index_string.  */
+      node = find_AT_string (ref->info, NO_INSERT);
       gcc_assert (node
 		  && (node->form == DW_FORM_strp
 		      || node->form == dwarf_FORM (DW_FORM_strx)));