jump label: Convert dynamic debug to use jump labels
Convert the 'dynamic debug' infrastructure to use jump labels. Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <b77627358cea3e27d7be4386f45f66219afb8452.1284733808.git.jbaron@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Jason Baron
Steven Rostedt
parent
8f7b50c514
commit
52159d98be
5 changed files with 26 additions and 132 deletions
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@ -1,6 +1,8 @@
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#ifndef _DYNAMIC_DEBUG_H
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#define _DYNAMIC_DEBUG_H
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#include <linux/jump_label.h>
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/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
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* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
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* use independent hash functions, to reduce the chance of false positives.
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@ -22,8 +24,6 @@ struct _ddebug {
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const char *function;
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const char *filename;
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const char *format;
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char primary_hash;
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char secondary_hash;
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unsigned int lineno:24;
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/*
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* The flags field controls the behaviour at the callsite.
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@ -33,6 +33,7 @@ struct _ddebug {
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#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
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#define _DPRINTK_FLAGS_DEFAULT 0
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unsigned int flags:8;
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char enabled;
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} __attribute__((aligned(8)));
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@ -42,33 +43,35 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
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#if defined(CONFIG_DYNAMIC_DEBUG)
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extern int ddebug_remove_module(const char *mod_name);
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#define __dynamic_dbg_enabled(dd) ({ \
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int __ret = 0; \
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if (unlikely((dynamic_debug_enabled & (1LL << DEBUG_HASH)) && \
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(dynamic_debug_enabled2 & (1LL << DEBUG_HASH2)))) \
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if (unlikely(dd.flags)) \
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__ret = 1; \
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__ret; })
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#define dynamic_pr_debug(fmt, ...) do { \
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__label__ do_printk; \
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__label__ out; \
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static struct _ddebug descriptor \
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__used \
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__attribute__((section("__verbose"), aligned(8))) = \
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{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH, \
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DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT }; \
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if (__dynamic_dbg_enabled(descriptor)) \
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{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
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_DPRINTK_FLAGS_DEFAULT }; \
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JUMP_LABEL(&descriptor.enabled, do_printk); \
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goto out; \
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do_printk: \
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printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); \
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out: ; \
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} while (0)
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#define dynamic_dev_dbg(dev, fmt, ...) do { \
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__label__ do_printk; \
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__label__ out; \
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static struct _ddebug descriptor \
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__used \
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__attribute__((section("__verbose"), aligned(8))) = \
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{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH, \
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DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT }; \
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if (__dynamic_dbg_enabled(descriptor)) \
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{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
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_DPRINTK_FLAGS_DEFAULT }; \
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JUMP_LABEL(&descriptor.enabled, do_printk); \
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goto out; \
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do_printk: \
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dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); \
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out: ; \
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} while (0)
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#else
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@ -26,19 +26,11 @@
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#include <linux/dynamic_debug.h>
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#include <linux/debugfs.h>
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#include <linux/slab.h>
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#include <linux/jump_label.h>
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extern struct _ddebug __start___verbose[];
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extern struct _ddebug __stop___verbose[];
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/* dynamic_debug_enabled, and dynamic_debug_enabled2 are bitmasks in which
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* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
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* use independent hash functions, to reduce the chance of false positives.
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*/
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long long dynamic_debug_enabled;
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EXPORT_SYMBOL_GPL(dynamic_debug_enabled);
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long long dynamic_debug_enabled2;
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EXPORT_SYMBOL_GPL(dynamic_debug_enabled2);
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struct ddebug_table {
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struct list_head link;
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char *mod_name;
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@ -87,26 +79,6 @@ static char *ddebug_describe_flags(struct _ddebug *dp, char *buf,
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return buf;
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}
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/*
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* must be called with ddebug_lock held
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*/
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static int disabled_hash(char hash, bool first_table)
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{
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struct ddebug_table *dt;
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char table_hash_value;
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list_for_each_entry(dt, &ddebug_tables, link) {
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if (first_table)
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table_hash_value = dt->ddebugs->primary_hash;
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else
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table_hash_value = dt->ddebugs->secondary_hash;
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if (dt->num_enabled && (hash == table_hash_value))
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return 0;
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}
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return 1;
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}
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/*
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* Search the tables for _ddebug's which match the given
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* `query' and apply the `flags' and `mask' to them. Tells
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@ -170,17 +142,9 @@ static void ddebug_change(const struct ddebug_query *query,
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dt->num_enabled++;
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dp->flags = newflags;
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if (newflags) {
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dynamic_debug_enabled |=
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(1LL << dp->primary_hash);
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dynamic_debug_enabled2 |=
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(1LL << dp->secondary_hash);
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enable_jump_label(&dp->enabled);
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} else {
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if (disabled_hash(dp->primary_hash, true))
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dynamic_debug_enabled &=
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~(1LL << dp->primary_hash);
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if (disabled_hash(dp->secondary_hash, false))
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dynamic_debug_enabled2 &=
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~(1LL << dp->secondary_hash);
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disable_jump_label(&dp->enabled);
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}
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if (verbose)
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printk(KERN_INFO
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@ -101,14 +101,6 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
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modname_flags = $(if $(filter 1,$(words $(modname))),\
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-D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
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#hash values
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ifdef CONFIG_DYNAMIC_DEBUG
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debug_flags = -D"DEBUG_HASH=$(shell ./scripts/basic/hash djb2 $(@D)$(modname))"\
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-D"DEBUG_HASH2=$(shell ./scripts/basic/hash r5 $(@D)$(modname))"
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else
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debug_flags =
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endif
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orig_c_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \
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$(ccflags-y) $(CFLAGS_$(basetarget).o)
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_c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
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@ -152,8 +144,7 @@ endif
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c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
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$(__c_flags) $(modkern_cflags) \
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-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags) \
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$(debug_flags)
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-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)
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a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
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$(__a_flags) $(modkern_aflags)
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@ -9,7 +9,7 @@
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# fixdep: Used to generate dependency information during build process
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# docproc: Used in Documentation/DocBook
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hostprogs-y := fixdep docproc hash
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hostprogs-y := fixdep docproc
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always := $(hostprogs-y)
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# fixdep is needed to compile other host programs
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@ -1,64 +0,0 @@
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/*
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* Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define DYNAMIC_DEBUG_HASH_BITS 6
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static const char *program;
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static void usage(void)
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{
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printf("Usage: %s <djb2|r5> <modname>\n", program);
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exit(1);
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}
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/* djb2 hashing algorithm by Dan Bernstein. From:
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* http://www.cse.yorku.ca/~oz/hash.html
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*/
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static unsigned int djb2_hash(char *str)
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{
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unsigned long hash = 5381;
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int c;
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c = *str;
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while (c) {
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hash = ((hash << 5) + hash) + c;
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c = *++str;
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}
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return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
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}
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static unsigned int r5_hash(char *str)
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{
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unsigned long hash = 0;
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int c;
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c = *str;
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while (c) {
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hash = (hash + (c << 4) + (c >> 4)) * 11;
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c = *++str;
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}
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return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
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}
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int main(int argc, char *argv[])
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{
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program = argv[0];
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if (argc != 3)
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usage();
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if (!strcmp(argv[1], "djb2"))
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printf("%d\n", djb2_hash(argv[2]));
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else if (!strcmp(argv[1], "r5"))
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printf("%d\n", r5_hash(argv[2]));
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else
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usage();
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exit(0);
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}
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