linux-kernel - [PATCH 1/4] perf symbols: add dso__insert

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Date:	Tue, 10 May 2016 19:04:02 -0700
From:	Chris Phlipot <cphlipot0@...il.com>
To:	adrian.hunter@...el.com, acme@...nel.org, peterz@...radead.org,
	mingo@...hat.com
Cc:	linux-kernel@...r.kernel.org, Chris Phlipot <cphlipot0@...il.com>
Subject: [PATCH 1/4] 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 ip using dso__find_symbol

2. symbol inserted at ip using the existing symbols__insert function

3. symbol still not found at ip 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@...il.com>
---
 tools/perf/util/symbol.c | 12 ++++++++++++
 tools/perf/util/symbol.h |  3 +++
 2 files changed, 15 insertions(+)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 2946295..21af8e8 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 07211c2..2b5e4ed 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,
-- 
2.7.4