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* [review] Compute msymbol hash codes in parallel
@ 2019-10-25 19:30 Christian Biesinger (Code Review)
  2019-10-29 19:44 ` Tom Tromey (Code Review)
                   ` (11 more replies)
  0 siblings, 12 replies; 13+ messages in thread
From: Christian Biesinger (Code Review) @ 2019-10-25 19:30 UTC (permalink / raw)
  To: gdb-patches; +Cc: Christian Biesinger

Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/308
......................................................................

Compute msymbol hash codes in parallel

This is for the msymbol_hash and msymbol_demangled_hash hashtables
in objfile_per_bfd_storage. This basically computes those hash
codes together with the demangled symbol name in the background,
before it inserts the symbols in the hash table.

gdb/ChangeLog:

2019-09-30  Christian Biesinger  <cbiesinger@google.com>

	* minsyms.c (add_minsym_to_hash_table): Use a previously computed
	hash code if possible.
	(add_minsym_to_demangled_hash_table): Likewise.
	(minimal_symbol_reader::install): Compute the hash codes for msymbol
	on the background thread.
	* symtab.h (struct minimal_symbol) <hash_value, demangled_hash_value>:
	Add these fields.

Change-Id: Ifaa3346e9998f05743bff9e2eaad3f83b954d071
---
M gdb/minsyms.c
1 file changed, 26 insertions(+), 15 deletions(-)



diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index 51894b2..9c134e8 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -141,12 +141,12 @@
 /* Add the minimal symbol SYM to an objfile's minsym hash table, TABLE.  */
 static void
 add_minsym_to_hash_table (struct minimal_symbol *sym,
-			  struct minimal_symbol **table)
+			  struct minimal_symbol **table,
+			  unsigned int hash_value)
 {
   if (sym->hash_next == NULL)
     {
-      unsigned int hash
-	= msymbol_hash (MSYMBOL_LINKAGE_NAME (sym)) % MINIMAL_SYMBOL_HASH_SIZE;
+      unsigned int hash = hash_value % MINIMAL_SYMBOL_HASH_SIZE;
 
       sym->hash_next = table[hash];
       table[hash] = sym;
@@ -157,18 +157,16 @@
    TABLE.  */
 static void
 add_minsym_to_demangled_hash_table (struct minimal_symbol *sym,
-				    struct objfile *objfile)
+				    struct objfile *objfile,
+				    unsigned int hash_value)
 {
   if (sym->demangled_hash_next == NULL)
     {
-      unsigned int hash = search_name_hash (MSYMBOL_LANGUAGE (sym),
-					    MSYMBOL_SEARCH_NAME (sym));
-
       objfile->per_bfd->demangled_hash_languages.set (MSYMBOL_LANGUAGE (sym));
 
       struct minimal_symbol **table
 	= objfile->per_bfd->msymbol_demangled_hash;
-      unsigned int hash_index = hash % MINIMAL_SYMBOL_HASH_SIZE;
+      unsigned int hash_index = hash_value % MINIMAL_SYMBOL_HASH_SIZE;
       sym->demangled_hash_next = table[hash_index];
       table[hash_index] = sym;
     }
@@ -1251,6 +1249,8 @@
 
 struct computed_hash_values {
   hashval_t mangled_name_hash;
+  unsigned int minsym_hash;
+  unsigned int minsym_demangled_hash;
 };
 
 /* Build (or rebuild) the minimal symbol hash tables.  This is necessary
@@ -1258,7 +1258,9 @@
    thus causing the internal minimal_symbol pointers to become jumbled.  */
   
 static void
-build_minimal_symbol_hash_tables (struct objfile *objfile)
+build_minimal_symbol_hash_tables
+  (struct objfile *objfile,
+   std::vector<computed_hash_values>& hash_values)
 {
   int i;
   struct minimal_symbol *msym;
@@ -1271,17 +1273,20 @@
     }
 
   /* Now, (re)insert the actual entries.  */
-  for ((i = objfile->per_bfd->minimal_symbol_count,
+  int mcount = objfile->per_bfd->minimal_symbol_count;
+  for ((i = 0,
 	msym = objfile->per_bfd->msymbols.get ());
-       i > 0;
-       i--, msym++)
+       i < mcount;
+       i++, msym++)
     {
       msym->hash_next = 0;
-      add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash);
+      add_minsym_to_hash_table (msym, objfile->per_bfd->msymbol_hash,
+				hash_values[i].minsym_hash);
 
       msym->demangled_hash_next = 0;
       if (MSYMBOL_SEARCH_NAME (msym) != MSYMBOL_LINKAGE_NAME (msym))
-	add_minsym_to_demangled_hash_table (msym, objfile);
+	add_minsym_to_demangled_hash_table
+	  (msym, objfile, hash_values[i].minsym_demangled_hash);
     }
 }
 
@@ -1391,6 +1396,12 @@
 		   size_t idx = msym - msymbols;
 		   hash_values[idx].mangled_name_hash = htab_hash_string (msym->name);
 		 }
+		size_t idx = msym - msymbols;
+		hash_values[idx].minsym_hash
+		  = msymbol_hash (MSYMBOL_LINKAGE_NAME (msym));
+		hash_values[idx].minsym_demangled_hash
+		  = search_name_hash (MSYMBOL_LANGUAGE (msym),
+				      MSYMBOL_SEARCH_NAME (msym));
 	     }
 	   {
 	     /* To limit how long we hold the lock, we only acquire it here
@@ -1409,7 +1420,7 @@
 	   }
 	 });
 
-      build_minimal_symbol_hash_tables (m_objfile);
+      build_minimal_symbol_hash_tables (m_objfile, hash_values);
     }
 }
 

-- 
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: Ifaa3346e9998f05743bff9e2eaad3f83b954d071
Gerrit-Change-Number: 308
Gerrit-PatchSet: 1
Gerrit-Owner: Christian Biesinger <cbiesinger@google.com>
Gerrit-MessageType: newchange

^ permalink raw reply	[flat|nested] 13+ messages in thread
end of thread, other threads:[~2019-11-27 21:40 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-25 19:30 [review] Compute msymbol hash codes in parallel Christian Biesinger (Code Review)
2019-10-29 19:44 ` Tom Tromey (Code Review)
2019-10-29 21:56 ` [review v3] " Christian Biesinger (Code Review)
2019-10-29 21:56 ` [review v2] " Christian Biesinger (Code Review)
2019-10-31  0:23 ` [review v4] " Christian Biesinger (Code Review)
2019-11-26 21:44 ` [review v5] " Christian Biesinger (Code Review)
2019-11-26 22:14 ` Tom Tromey (Code Review)
2019-11-26 22:23 ` [review v6] " Christian Biesinger (Code Review)
2019-11-26 22:25 ` Christian Biesinger (Code Review)
2019-11-26 22:27 ` [review v7] " Christian Biesinger (Code Review)
2019-11-27 18:04 ` Tom Tromey (Code Review)
2019-11-27 21:40 ` [pushed] " Sourceware to Gerrit sync (Code Review)
2019-11-27 21:40 ` Sourceware to Gerrit sync (Code Review)

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