Hi.
As seen in r265663 having htab_hash_string accepting const char * would
report a compilation error. The void * argument is needed for old C-style
htab used in libiberty. I'm suggesting to come up with htab_hash_string_vptr and
change signature of the old one (htab_hash_string). And putting these into
hashtab.h will make it inlinable in C++-style hash table.
Patch survives regression tests on ppc64le-linux-gnu.
Total cc1 change with the patch:
+0.0% +2.09Ki
Hope it's acceptable.
Thanks,
Martin
gcc/ChangeLog:
2018-10-31 Martin Liska <[email protected]>
* gengtype-state.c (read_state): Use newly added
htab_hash_string_vptr.
* gensupport.c (gen_mnemonic_attr): Likewise.
(check_define_attr_duplicates): Likewise.
* godump.c (go_finish): Likewise.
include/ChangeLog:
2018-10-31 Martin Liska <[email protected]>
* hashtab.h (htab_hash_string): Change signature
to const char * and make it static inline.
(htab_hash_string_vptr): Likewise.
libcpp/ChangeLog:
2018-10-31 Martin Liska <[email protected]>
* files.c (_cpp_init_files): Use htab_hash_string_vptr.
libiberty/ChangeLog:
2018-10-31 Martin Liska <[email protected]>
* hashtab.c:
(htab_hash_string): Move to header file.
---
gcc/gengtype-state.c | 2 +-
gcc/gensupport.c | 4 ++--
gcc/godump.c | 6 +++---
include/hashtab.h | 47 ++++++++++++++++++++++++++++++++++++++++++--
libcpp/files.c | 2 +-
libiberty/hashtab.c | 38 -----------------------------------
6 files changed, 52 insertions(+), 47 deletions(-)
diff --git a/gcc/gengtype-state.c b/gcc/gengtype-state.c
index 6a3b981eedc..facff4a29d7 100644
--- a/gcc/gengtype-state.c
+++ b/gcc/gengtype-state.c
@@ -2588,7 +2588,7 @@ read_state (const char *path)
state_seen_types =
htab_create (2017, hash_type_number, equals_type_number, NULL);
state_ident_tab =
- htab_create (4027, htab_hash_string, string_eq, NULL);
+ htab_create (4027, htab_hash_string_vptr, string_eq, NULL);
read_state_version (version_string);
read_state_srcdir ();
read_state_languages ();
diff --git a/gcc/gensupport.c b/gcc/gensupport.c
index 1d76af7ce5c..2f865d918f3 100644
--- a/gcc/gensupport.c
+++ b/gcc/gensupport.c
@@ -2434,7 +2434,7 @@ gen_mnemonic_attr (void)
if (!mnemonic_attr)
return;
- mnemonic_htab = htab_create_alloc (MNEMONIC_HTAB_SIZE, htab_hash_string,
+ mnemonic_htab = htab_create_alloc (MNEMONIC_HTAB_SIZE, htab_hash_string_vptr,
htab_eq_string, 0, xcalloc, free);
for (elem = define_insn_queue; elem; elem = elem->next)
@@ -2492,7 +2492,7 @@ check_define_attr_duplicates ()
char * attr_name;
void **slot;
- attr_htab = htab_create (500, htab_hash_string, htab_eq_string, NULL);
+ attr_htab = htab_create (500, htab_hash_string_vptr, htab_eq_string, NULL);
for (elem = define_attr_queue; elem; elem = elem->next)
{
diff --git a/gcc/godump.c b/gcc/godump.c
index baf21e27eec..7098ac80a91 100644
--- a/gcc/godump.c
+++ b/gcc/godump.c
@@ -1377,11 +1377,11 @@ go_finish (const char *filename)
real_debug_hooks->finish (filename);
- container.type_hash = htab_create (100, htab_hash_string,
+ container.type_hash = htab_create (100, htab_hash_string_vptr,
string_hash_eq, NULL);
- container.invalid_hash = htab_create (10, htab_hash_string,
+ container.invalid_hash = htab_create (10, htab_hash_string_vptr,
string_hash_eq, NULL);
- container.keyword_hash = htab_create (50, htab_hash_string,
+ container.keyword_hash = htab_create (50, htab_hash_string_vptr,
string_hash_eq, NULL);
obstack_init (&container.type_obstack);
diff --git a/include/hashtab.h b/include/hashtab.h
index 531eb101ff7..44bce8c2a6b 100644
--- a/include/hashtab.h
+++ b/include/hashtab.h
@@ -189,8 +189,51 @@ extern htab_hash htab_hash_pointer;
/* An equality function for pointers. */
extern htab_eq htab_eq_pointer;
-/* A hash function for null-terminated strings. */
-extern hashval_t htab_hash_string (const void *);
+/* Hash STR as a null-terminated string.
+
+ Copied from gcc/hashtable.c. Zack had the following to say with respect
+ to applicability, though note that unlike hashtable.c, this hash table
+ implementation re-hashes rather than chain buckets.
+
+ http://gcc.gnu.org/ml/gcc-patches/2001-08/msg01021.html
+ From: Zack Weinberg <[email protected]>
+ Date: Fri, 17 Aug 2001 02:15:56 -0400
+
+ I got it by extracting all the identifiers from all the source code
+ I had lying around in mid-1999, and testing many recurrences of
+ the form "H_n = H_{n-1} * K + c_n * L + M" where K, L, M were either
+ prime numbers or the appropriate identity. This was the best one.
+ I don't remember exactly what constituted "best", except I was
+ looking at bucket-length distributions mostly.
+
+ So it should be very good at hashing identifiers, but might not be
+ as good at arbitrary strings.
+
+ I'll add that it thoroughly trounces the hash functions recommended
+ for this use at http://burtleburtle.net/bob/hash/index.html, both
+ on speed and bucket distribution. I haven't tried it against the
+ function they just started using for Perl's hashes. */
+
+static inline hashval_t
+htab_hash_string (const char *str)
+{
+ hashval_t r = 0;
+ unsigned char c;
+
+ while ((c = *str++) != 0)
+ r = r * 67 + c - 113;
+
+ return r;
+}
+
+/* Hash P as a null-terminated string. */
+
+static inline hashval_t
+htab_hash_string_vptr (const PTR p)
+{
+ return htab_hash_string ((const char *)p);
+}
+
/* An iterative hash function for arbitrary data. */
extern hashval_t iterative_hash (const void *, size_t, hashval_t);
diff --git a/libcpp/files.c b/libcpp/files.c
index 08b7c647c91..e4eb34e7d55 100644
--- a/libcpp/files.c
+++ b/libcpp/files.c
@@ -1311,7 +1311,7 @@ _cpp_init_files (cpp_reader *pfile)
pfile->dir_hash = htab_create_alloc (127, file_hash_hash, file_hash_eq,
NULL, xcalloc, free);
allocate_file_hash_entries (pfile);
- pfile->nonexistent_file_hash = htab_create_alloc (127, htab_hash_string,
+ pfile->nonexistent_file_hash = htab_create_alloc (127, htab_hash_string_vptr,
nonexistent_file_hash_eq,
NULL, xcalloc, free);
obstack_specify_allocation (&pfile->nonexistent_file_ob, 0, 0,
diff --git a/libiberty/hashtab.c b/libiberty/hashtab.c
index ca392647d4a..b6821502d15 100644
--- a/libiberty/hashtab.c
+++ b/libiberty/hashtab.c
@@ -803,44 +803,6 @@ htab_collisions (htab_t htab)
return (double) htab->collisions / (double) htab->searches;
}
-/* Hash P as a null-terminated string.
-
- Copied from gcc/hashtable.c. Zack had the following to say with respect
- to applicability, though note that unlike hashtable.c, this hash table
- implementation re-hashes rather than chain buckets.
-
- http://gcc.gnu.org/ml/gcc-patches/2001-08/msg01021.html
- From: Zack Weinberg <[email protected]>
- Date: Fri, 17 Aug 2001 02:15:56 -0400
-
- I got it by extracting all the identifiers from all the source code
- I had lying around in mid-1999, and testing many recurrences of
- the form "H_n = H_{n-1} * K + c_n * L + M" where K, L, M were either
- prime numbers or the appropriate identity. This was the best one.
- I don't remember exactly what constituted "best", except I was
- looking at bucket-length distributions mostly.
-
- So it should be very good at hashing identifiers, but might not be
- as good at arbitrary strings.
-
- I'll add that it thoroughly trounces the hash functions recommended
- for this use at http://burtleburtle.net/bob/hash/index.html, both
- on speed and bucket distribution. I haven't tried it against the
- function they just started using for Perl's hashes. */
-
-hashval_t
-htab_hash_string (const PTR p)
-{
- const unsigned char *str = (const unsigned char *) p;
- hashval_t r = 0;
- unsigned char c;
-
- while ((c = *str++) != 0)
- r = r * 67 + c - 113;
-
- return r;
-}
-
/* DERIVED FROM:
--------------------------------------------------------------------
lookup2.c, by Bob Jenkins, December 1996, Public Domain.
