[pushed] Add a fast_hash function in common-utils
Commit Message
Sourceware to Gerrit sync has submitted this change.
Change URL: https://gnutoolchain-gerrit.osci.io/r/c/binutils-gdb/+/38
......................................................................
Add a fast_hash function in common-utils
Also updates a caller in symtab.c. For now this just calls htab_hash_string
but the next patch will change it to xxhash, if available.
gdb/ChangeLog:
2019-10-22 Christian Biesinger <cbiesinger@google.com>
* utils.h (fast_hash): New function.
* symtab.c (hash_demangled_name_entry): Call new function
fast_hash.
Change-Id: I77cac0d9aa78fc65316a2af449f52edcae72dc9b
---
M gdb/ChangeLog
M gdb/symtab.c
M gdb/utils.h
3 files changed, 18 insertions(+), 1 deletion(-)
@@ -1,5 +1,11 @@
2019-10-22 Christian Biesinger <cbiesinger@google.com>
+ * utils.h (fast_hash): New function.
+ * symtab.c (hash_demangled_name_entry): Call new function
+ fast_hash.
+
+2019-10-22 Christian Biesinger <cbiesinger@google.com>
+
* symtab.c (struct demangled_name_entry): Change type of mangled
to gdb::string_view. Also adds a constructor that takes the
mangled name.
@@ -70,6 +70,7 @@
#include <algorithm>
#include "gdbsupport/gdb_string_view.h"
#include "gdbsupport/pathstuff.h"
+#include "gdbsupport/common-utils.h"
/* Forward declarations for local functions. */
@@ -727,7 +728,7 @@
const struct demangled_name_entry *e
= (const struct demangled_name_entry *) data;
- return iterative_hash (e->mangled.data (), e->mangled.length (), 0);
+ return fast_hash (e->mangled.data (), e->mangled.length ());
}
/* Equality function for the demangled name hash. */
@@ -567,4 +567,14 @@
const gdb_byte *source, ULONGEST source_offset,
ULONGEST nbits, int bits_big_endian);
+/* A fast hashing function. This can be used to hash strings in a fast way
+ when the length is known. If no fast hashing library is available, falls
+ back to iterative_hash from libiberty. */
+
+static inline unsigned int
+fast_hash (const char* str, size_t len)
+{
+ return iterative_hash (str, len, 0);
+}
+
#endif /* UTILS_H */