Allow zero sized symbols in the address cache

Apparently there are situations where the compiler generates entries
in the symbol table with zero size which are still referenced by some
callstacks. After commit d8d56b7e we ended up losing the symbol names
in such cases. This patch fixes it again and restores the symbol names
for such zero-size symbols.

Change-Id: If98f68626ab4251ccfed89d791ebd333f6a6a60a
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

5 files changed, 8 insertions, 5 deletions

diff --git a/app/perfaddresscache.cpp b/app/perfaddresscache.cpp
index 18edef1..46938cf 100644
--- a/app/perfaddresscache.cpp
+++ b/app/perfaddresscache.cpp
@@ -86,7 +86,7 @@ PerfAddressCache::SymbolCacheEntry PerfAddressCache::findSymbol(const QByteArray
 
     --it;
 
-    if (it->offset <= relAddr && it->offset + it->size > relAddr) {
+    if (it->offset <= relAddr && (it->offset + it->size > relAddr || (it->size == 0))) {
         // demangle symbols on demand instead of demangling all symbols directly
         // hopefully most of the symbols we won't ever encounter after all
         if (!it->demangled) {
diff --git a/app/perfaddresscache.h b/app/perfaddresscache.h
index 6e18a34..6bc780d 100644
--- a/app/perfaddresscache.h
+++ b/app/perfaddresscache.h
@@ -48,7 +48,7 @@ public:
             , symname(symname)
         {}
 
-        bool isValid() const { return size != 0; }
+        bool isValid() const { return !symname.isEmpty(); }
 
         quint64 offset;
         quint64 size;
diff --git a/tests/auto/addresscache/tst_addresscache.cpp b/tests/auto/addresscache/tst_addresscache.cpp
index 8136682..6387a4e 100644
--- a/tests/auto/addresscache/tst_addresscache.cpp
+++ b/tests/auto/addresscache/tst_addresscache.cpp
@@ -72,7 +72,7 @@ private slots:
         QVERIFY(!cache.findSymbol(libfoo_a, 0).isValid());
         QVERIFY(!cache.findSymbol(libfoo_b, 0).isValid());
 
-        cache.setSymbolCache(libfoo_a, {{0x100, 10, "Foo"}});
+        cache.setSymbolCache(libfoo_a, {{0x100, 10, "Foo"}, {0x11a, 0, "FooZ"}, {0x12a, 10, "FooN"}});
         for (auto addr : {0x100, 0x100 + 9}) {
             const auto cached = cache.findSymbol(libfoo_a, addr);
             QVERIFY(cached.isValid());
@@ -83,6 +83,7 @@ private slots:
         QVERIFY(!cache.findSymbol(libfoo_a, 0x100 + 10).isValid());
         QVERIFY(!cache.findSymbol(libfoo_b, 0x100).isValid());
         QVERIFY(!cache.findSymbol(libfoo_b, 0x100 + 9).isValid());
+        QVERIFY(cache.findSymbol(libfoo_a, 0x11a + 1).isValid());
     }
 };
 
diff --git a/tests/auto/perfdata/vector_static_gcc/perf.data.expected.txt b/tests/auto/perfdata/vector_static_gcc/perf.data.expected.txt
index d494b31..9ef4378 100644
--- a/tests/auto/perfdata/vector_static_gcc/perf.data.expected.txt
+++ b/tests/auto/perfdata/vector_static_gcc/perf.data.expected.txt
@@ -711,7 +711,8 @@ vector_static_g	349054	349054	65149.476874692
 vector_static_g	349054	349054	65149.477126147
 	cycles: 315591
 
-	400480	<.plt+400480> vector_static_gcc_v9.1.0 /home/milian/projects/kdab/rnd/hotspot/3rdparty/perfparser/tests/auto/perfdata/vector_static_gcc/vector_static_gcc_v9.1.0 
+	400480
+	400430	_init vector_static_gcc_v9.1.0 /home/milian/projects/kdab/rnd/hotspot/3rdparty/perfparser/tests/auto/perfdata/vector_static_gcc/vector_static_gcc_v9.1.0 
 	40155c	/usr/include/c++/9.1.0/bits/stl_algo.h:4449:13
 	40152b	/usr/include/c++/9.1.0/bits/stl_algo.h:4441:5	std::generate_n<std::back_insert_iterator<std::vector<double> >, int, main()::<lambda()> > vector_static_gcc_v9.1.0 /home/milian/projects/kdab/rnd/hotspot/3rdparty/perfparser/tests/auto/perfdata/vector_static_gcc/vector_static_gcc_v9.1.0 
 	40152b	../../../manual/clients/vector.cpp:16:6
diff --git a/tests/auto/perfdata/vector_static_gcc/perf.data.zstd.expected.txt b/tests/auto/perfdata/vector_static_gcc/perf.data.zstd.expected.txt
index e62f41a..f7af600 100644
--- a/tests/auto/perfdata/vector_static_gcc/perf.data.zstd.expected.txt
+++ b/tests/auto/perfdata/vector_static_gcc/perf.data.zstd.expected.txt
@@ -247,7 +247,8 @@ vector_static_g	267677	267677	9952.368475245
 vector_static_g	267677	267677	9952.368668898
 	cycles: 415081
 
-	400490	<.plt+400490> vector_static_gcc_v9.1.0 /home/milian/projects/kdab/rnd/hotspot/3rdparty/perfparser/tests/auto/perfdata/vector_static_gcc/vector_static_gcc_v9.1.0 
+	400490
+	400430	_init vector_static_gcc_v9.1.0 /home/milian/projects/kdab/rnd/hotspot/3rdparty/perfparser/tests/auto/perfdata/vector_static_gcc/vector_static_gcc_v9.1.0 
 	401572	/usr/include/c++/9.1.0/bits/stl_algo.h:4449:13
 	40152b	/usr/include/c++/9.1.0/bits/stl_algo.h:4441:5	std::generate_n<std::back_insert_iterator<std::vector<double> >, int, main()::<lambda()> > vector_static_gcc_v9.1.0 /home/milian/projects/kdab/rnd/hotspot/3rdparty/perfparser/tests/auto/perfdata/vector_static_gcc/vector_static_gcc_v9.1.0 
 	40152b	../../../manual/clients/vector.cpp:16:6