[review] Precompute hash value for symbol_set_names
Christian Biesinger (Code Review)
gerrit@gnutoolchain-gerrit.osci.io
Fri Oct 25 19:30:00 GMT 2019
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/307
......................................................................
Precompute hash value for symbol_set_names
We can also compute the hash for the mangled name on a background
thread so make this function even faster (about a 7% speedup).
gdb/ChangeLog:
2019-10-03 Christian Biesinger <cbiesinger@google.com>
* minsyms.c (minimal_symbol_reader::install): Also compute the hash
of the mangled name on the background thread.
* symtab.c (symbol_set_names): Allow passing in the hash of the
linkage_name.
* symtab.h (symbol_set_names): Likewise.
Change-Id: I044449e7eb60cffc1c43efd3412f2b485bd9faac
---
M gdb/minsyms.c
M gdb/symtab.c
M gdb/symtab.h
3 files changed, 22 insertions(+), 6 deletions(-)
diff --git a/gdb/minsyms.c b/gdb/minsyms.c
index bfcd5d5..51894b2 100644
--- a/gdb/minsyms.c
+++ b/gdb/minsyms.c
@@ -1249,6 +1249,10 @@
return (mcount);
}
+struct computed_hash_values {
+ hashval_t mangled_name_hash;
+};
+
/* Build (or rebuild) the minimal symbol hash tables. This is necessary
after compacting or sorting the table since the entries move around
thus causing the internal minimal_symbol pointers to become jumbled. */
@@ -1365,6 +1369,8 @@
std::mutex demangled_mutex;
#endif
+ std::vector<computed_hash_values> hash_values (mcount);
+
msymbols = m_objfile->per_bfd->msymbols.get ();
gdb::parallel_for_each
(&msymbols[0], &msymbols[mcount],
@@ -1381,6 +1387,9 @@
(msym, demangled_name,
&m_objfile->per_bfd->storage_obstack);
msym->name_set = 1;
+
+ size_t idx = msym - msymbols;
+ hash_values[idx].mangled_name_hash = htab_hash_string (msym->name);
}
}
{
@@ -1391,9 +1400,11 @@
#endif
for (minimal_symbol *msym = start; msym < end; ++msym)
{
+ size_t idx = msym - msymbols;
symbol_set_names (msym, msym->name,
strlen (msym->name), 0,
- m_objfile->per_bfd);
+ m_objfile->per_bfd,
+ hash_values[idx].mangled_name_hash);
}
}
});
diff --git a/gdb/symtab.c b/gdb/symtab.c
index abc6a77..06d8370 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -825,7 +825,7 @@
void
symbol_set_names (struct general_symbol_info *gsymbol,
const char *linkage_name, int len, bool copy_name,
- struct objfile_per_bfd_storage *per_bfd)
+ struct objfile_per_bfd_storage *per_bfd, hashval_t hash)
{
struct demangled_name_entry **slot;
/* A 0-terminated copy of the linkage name. */
@@ -868,9 +868,11 @@
linkage_name_copy = linkage_name;
struct demangled_name_entry entry (gdb::string_view (linkage_name_copy, len));
+ if (hash == 0)
+ hash = hash_demangled_name_entry (&entry);
slot = ((struct demangled_name_entry **)
- htab_find_slot (per_bfd->demangled_names_hash.get (),
- &entry, INSERT));
+ htab_find_slot_with_hash (per_bfd->demangled_names_hash.get (),
+ &entry, hash, INSERT));
/* If this name is not in the hash table, add it. */
if (*slot == NULL
diff --git a/gdb/symtab.h b/gdb/symtab.h
index 7d41de9..48392b9 100644
--- a/gdb/symtab.h
+++ b/gdb/symtab.h
@@ -514,13 +514,16 @@
(symbol)->ginfo.name = (linkage_name)
/* Set the linkage and natural names of a symbol, by demangling
- the linkage name. */
+ the linkage name. Optionally, HASH can be set to the value
+ of htab_hash_string (linkage_name) (if nullterminated), to
+ speed up this function. */
#define SYMBOL_SET_NAMES(symbol,linkage_name,len,copy_name,objfile) \
symbol_set_names (&(symbol)->ginfo, linkage_name, len, copy_name, \
(objfile)->per_bfd)
extern void symbol_set_names (struct general_symbol_info *symbol,
const char *linkage_name, int len, bool copy_name,
- struct objfile_per_bfd_storage *per_bfd);
+ struct objfile_per_bfd_storage *per_bfd,
+ hashval_t hash = 0);
/* Now come lots of name accessor macros. Short version as to when to
use which: Use SYMBOL_NATURAL_NAME to refer to the name of the
--
Gerrit-Project: binutils-gdb
Gerrit-Branch: master
Gerrit-Change-Id: I044449e7eb60cffc1c43efd3412f2b485bd9faac
Gerrit-Change-Number: 307
Gerrit-PatchSet: 1
Gerrit-Owner: Christian Biesinger <cbiesinger@google.com>
Gerrit-MessageType: newchange
More information about the Gdb-patches
mailing list