perf symbols: Add dso__insert_symbol function

The current method for inserting symbols is to use the symbols__insert()
function. However symbols__insert() does not update the dso symbol
cache.  This causes problems in the following scenario:

1. symbol not found at addr using dso__find_symbol

2. symbol inserted at addr using the existing symbols__insert function

3. symbol still not found at addr using dso__find_symbol() because cache isn't
   updated. This is undesired behavior.

The undesired behavior in (3) is addressed by creating a new function,
dso__insert_symbol() to both insert the symbol and update the symbol
cache if necessary.

If dso__insert_symbol() is used in (2) instead of symbols__insert(),
then the undesired behavior in (3) is avoided.

Signed-off-by: Chris Phlipot <cphlipot0@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1462937209-6032-2-git-send-email-cphlipot0@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 15 insertions, 0 deletions

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 2946295ca502..21af8e8891fe 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -413,6 +413,18 @@ void dso__reset_find_symbol_cache(struct dso *dso)
         }
 }
 
+void dso__insert_symbol(struct dso *dso, enum map_type type, struct symbol *sym)
+{
+        symbols__insert(&dso->symbols[type], sym);
+
+        /* update the symbol cache if necessary */
+        if (dso->last_find_result[type].addr >= sym->start &&
+            (dso->last_find_result[type].addr < sym->end ||
+            sym->start == sym->end)) {
+                dso->last_find_result[type].symbol = sym;
+        }
+}
+
 struct symbol *dso__find_symbol(struct dso *dso,
                                 enum map_type type, u64 addr)
 {
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 07211c2f8456..2b5e4ed76fcb 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -246,6 +246,9 @@ int __dso__load_kallsyms(struct dso *dso, const char *filename, struct map *map,
 int dso__load_kallsyms(struct dso *dso, const char *filename, struct map *map,
                        symbol_filter_t filter);
 
+void dso__insert_symbol(struct dso *dso, enum map_type type,
+                        struct symbol *sym);
+
 struct symbol *dso__find_symbol(struct dso *dso, enum map_type type,
                                 u64 addr);
 struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,