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 fc12536 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. Fixes: KDAB/hotspot#252 Change-Id: Ib11521bc88f719811559d1e20f27c275eb8e5606
KDAB · Sep 25, 2020 · b0266cf · b0266cf
1 parent 617194e
commit b0266cf
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Showing 5 changed files with 8 additions and 5 deletions.
diff --git 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
@@ -48,7 +48,7 @@ class PerfAddressCache
             , 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
@@ -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
@@ -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
@@ -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