Ensure names are visible in backtrace by moving functions to a shared library

Name resolving does not necessarily work for static functions.

4 files changed, 35 insertions, 15 deletions

diff --git a/vespalib/src/tests/signalhandler/CMakeLists.txt b/vespalib/src/tests/signalhandler/CMakeLists.txt
index c33cdcf10cd..4f78eb2e82d 100644
--- a/vespalib/src/tests/signalhandler/CMakeLists.txt
+++ b/vespalib/src/tests/signalhandler/CMakeLists.txt
@@ -1,9 +1,16 @@
 # Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+vespa_add_library(vespalib_signalhandler_test_my_shared_library TEST
+    SOURCES
+    my_shared_library.cpp
+    DEPENDS
+    vespalib
+)
 vespa_add_executable(vespalib_signalhandler_test_app TEST
     SOURCES
     signalhandler_test.cpp
     DEPENDS
     vespalib
+    vespalib_signalhandler_test_my_shared_library
     GTest::GTest
 )
 vespa_add_test(NAME vespalib_signalhandler_test_app NO_VALGRIND COMMAND vespalib_signalhandler_test_app)
diff --git a/vespalib/src/tests/signalhandler/my_shared_library.cpp b/vespalib/src/tests/signalhandler/my_shared_library.cpp
new file mode 100644
index 00000000000..5663f6c4ba0
--- /dev/null
+++ b/vespalib/src/tests/signalhandler/my_shared_library.cpp
@@ -0,0 +1,19 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "my_shared_library.h"
+#include <vespa/vespalib/util/signalhandler.h>
+
+// This tiny library exists solely as a way to ensure we get visible function names in our backtrace,
+// as that is not necessarily the case for statically linked functions.
+
+// Could have used a single std::barrier<no op functor> here, but when using explicit
+// phase latches it sort of feels like the semantics are more immediately obvious.
+void my_cool_function(std::latch& arrival_latch, std::latch& departure_latch) {
+    arrival_latch.arrive_and_wait();
+    // Twiddle thumbs in departure latch until main test thread has dumped our stack
+    departure_latch.arrive_and_wait();
+}
+
+vespalib::string my_totally_tubular_and_groovy_function() {
+    return vespalib::SignalHandler::get_cross_thread_stack_trace(pthread_self());
+}
diff --git a/vespalib/src/tests/signalhandler/my_shared_library.h b/vespalib/src/tests/signalhandler/my_shared_library.h
new file mode 100644
index 00000000000..e48a6d91a4f
--- /dev/null
+++ b/vespalib/src/tests/signalhandler/my_shared_library.h
@@ -0,0 +1,8 @@
+// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/vespalib/stllike/string.h>
+#include <latch>
+
+void my_cool_function(std::latch&, std::latch&) __attribute__((noinline));
+
+vespalib::string my_totally_tubular_and_groovy_function() __attribute__((noinline));
diff --git a/vespalib/src/tests/signalhandler/signalhandler_test.cpp b/vespalib/src/tests/signalhandler/signalhandler_test.cpp
index f15233e78a3..9e1052bb588 100644
--- a/vespalib/src/tests/signalhandler/signalhandler_test.cpp
+++ b/vespalib/src/tests/signalhandler/signalhandler_test.cpp
@@ -1,5 +1,6 @@
 // Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 
+#include "my_shared_library.h"
 #include <vespa/vespalib/util/signalhandler.h>
 #include <vespa/vespalib/gtest/gtest.h>
 #include <gmock/gmock.h>
@@ -35,16 +36,6 @@ TEST(SignalHandlerTest, signal_handler_can_intercept_hooked_signals)
     EXPECT_EQ(0, system("res=`./vespalib_victim_app`; test \"$res\" = \"GOT TERM\""));
 }
 
-void my_cool_function(std::latch&, std::latch&) __attribute__((noinline));
-
-// Could have used a single std::barrier<no op functor> here, but when using explicit
-// phase latches it sort of feels like the semantics are more immediately obvious.
-void my_cool_function(std::latch& arrival_latch, std::latch& departure_latch) {
-    arrival_latch.arrive_and_wait();
-    // Twiddle thumbs in departure latch until main test thread has dumped our stack
-    departure_latch.arrive_and_wait();
-}
-
 TEST(SignalHandlerTest, can_dump_stack_of_another_thread)
 {
     std::latch arrival_latch(2);
@@ -73,11 +64,6 @@ TEST(SignalHandlerTest, dumping_stack_of_an_ex_thread_does_not_crash)
     EXPECT_EQ(trace, "(pthread_kill() failed; could not get backtrace)");
 }
 
-string my_totally_tubular_and_groovy_function() __attribute__((noinline));
-string my_totally_tubular_and_groovy_function() {
-    return SignalHandler::get_cross_thread_stack_trace(pthread_self());
-}
-
 TEST(SignalHandlerTest, can_get_stack_trace_of_own_thread)
 {
     auto trace = my_totally_tubular_and_groovy_function();