perf_counter tools: struct symbol priv area

When creating a dso instance allow asking that all symbols in this dso
have a private area just before the symbol.

perf top will use this for its counters, etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20090528175513.GD4747@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 24 insertions, 10 deletions

diff --git a/Documentation/perf_counter/util/symbol.c b/Documentation/perf_counter/util/symbol.c
index d06de2cfcdc6..7088206244ac 100644
--- a/Documentation/perf_counter/util/symbol.c
+++ b/Documentation/perf_counter/util/symbol.c
@@ -7,22 +7,27 @@
 #include <elf.h>
 
 static struct symbol *symbol__new(uint64_t start, uint64_t len,
-                                  const char *name)
+                                  const char *name, unsigned int priv_size)
 {
-        struct symbol *self = malloc(sizeof(*self) + strlen(name) + 1);
+        size_t namelen = strlen(name) + 1;
+        struct symbol *self = malloc(priv_size + sizeof(*self) + namelen);
 
         if (self != NULL) {
+                if (priv_size) {
+                        memset(self, 0, priv_size);
+                        self = ((void *)self) + priv_size;
+                }
                 self->start = start;
                 self->end   = start + len;
-                strcpy(self->name, name);
+                memcpy(self->name, name, namelen);
         }
 
         return self;
 }
 
-static void symbol__delete(struct symbol *self)
+static void symbol__delete(struct symbol *self, unsigned int priv_size)
 {
-        free(self);
+        free(((void *)self) - priv_size);
 }
 
 static size_t symbol__fprintf(struct symbol *self, FILE *fp)
@@ -31,13 +36,14 @@ static size_t symbol__fprintf(struct symbol *self, FILE *fp)
                        self->start, self->end, self->name);
 }
 
-struct dso *dso__new(const char *name)
+struct dso *dso__new(const char *name, unsigned int sym_priv_size)
 {
         struct dso *self = malloc(sizeof(*self) + strlen(name) + 1);
 
         if (self != NULL) {
                 strcpy(self->name, name);
                 self->syms = RB_ROOT;
+                self->sym_priv_size = sym_priv_size;
         }
 
         return self;
@@ -51,7 +57,7 @@ static void dso__delete_symbols(struct dso *self)
         while (next) {
                 pos = rb_entry(next, struct symbol, rb_node);
                 next = rb_next(&pos->rb_node);
-                symbol__delete(pos);
+                symbol__delete(pos, self->sym_priv_size);
         }
 }
 
@@ -189,7 +195,8 @@ int dso__load_kallsyms(struct dso *self)
                 /*
                  * Well fix up the end later, when we have all sorted.
                  */
-                sym = symbol__new(start, 0xdead, line + len + 2);
+                sym = symbol__new(start, 0xdead, line + len + 2,
+                                  self->sym_priv_size);
 
                 if (sym == NULL)
                         goto out_delete_line;
@@ -340,7 +347,8 @@ static int dso__load_sym(struct dso *self, int fd, const char *name)
                 sym.st_value -= shdr.sh_addr - shdr.sh_offset;
 
                 f = symbol__new(sym.st_value, sym.st_size,
-                                elf_sym__name(&sym, symstrs));
+                                elf_sym__name(&sym, symstrs),
+                                self->sym_priv_size);
                 if (!f)
                         goto out_elf_end;
 
diff --git a/Documentation/perf_counter/util/symbol.h b/Documentation/perf_counter/util/symbol.h
index 6dffe76a28f0..9e120af9c71f 100644
--- a/Documentation/perf_counter/util/symbol.h
+++ b/Documentation/perf_counter/util/symbol.h
@@ -15,12 +15,18 @@ struct symbol {
 struct dso {
         struct list_head node;
         struct rb_root   syms;
+        unsigned int     sym_priv_size;
         char             name[0];
 };
 
-struct dso *dso__new(const char *name);
+struct dso *dso__new(const char *name, unsigned int sym_priv_size);
 void dso__delete(struct dso *self);
 
+static inline void *dso__sym_priv(struct dso *self, struct symbol *sym)
+{
+        return ((void *)sym) - self->sym_priv_size;
+}
+
 struct symbol *dso__find_symbol(struct dso *self, uint64_t ip);
 
 int dso__load_kallsyms(struct dso *self);