Fix weak function lookups
* Linker now correctly resolves function defined
with __attribute__((weak)).
Bug: https://code.google.com/p/android/issues/detail?id=70206
Change-Id: I82efb905676c25fefb1b11a13f5fecb0f1384657
diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 6d63ad6..0b60ef5 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -118,7 +118,7 @@
if (sym != NULL) {
unsigned bind = ELF_ST_BIND(sym->st_info);
- if (bind == STB_GLOBAL && sym->st_shndx != 0) {
+ if ((bind == STB_GLOBAL || bind == STB_WEAK) && sym->st_shndx != 0) {
return reinterpret_cast<void*>(sym->st_value + found->load_bias);
}
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 49cbb7d..8b89183 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -254,6 +254,18 @@
ASSERT_TRUE(addr != NULL);
}
+TEST(dlfcn, dlsym_weak_func) {
+ dlerror();
+ void* handle = dlopen("libtest_dlsym_weak_func.so",RTLD_NOW);
+ ASSERT_TRUE(handle != NULL);
+
+ int (*weak_func)();
+ weak_func = reinterpret_cast<int (*)()>(dlsym(handle, "weak_func"));
+ ASSERT_TRUE(weak_func != NULL) << "dlerror: " << dlerror();
+ EXPECT_EQ(42, weak_func());
+ dlclose(handle);
+}
+
TEST(dlfcn, dlopen_symlink) {
void* handle1 = dlopen("libdlext_test.so", RTLD_NOW);
void* handle2 = dlopen("libdlext_test_v2.so", RTLD_NOW);
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index e75582d..67ea562 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -103,3 +103,15 @@
build_type := host
include $(TEST_PATH)/Android.build.mk
+# -----------------------------------------------------------------------------
+# Library with weak function
+# -----------------------------------------------------------------------------
+libtest_dlsym_weak_func_src_files := \
+ dlsym_weak_function.cpp
+
+module := libtest_dlsym_weak_func
+build_target := SHARED_LIBRARY
+build_type := target
+include $(TEST_PATH)/Android.build.mk
+build_type := host
+include $(TEST_PATH)/Android.build.mk
diff --git a/tests/libs/dlsym_weak_function.cpp b/tests/libs/dlsym_weak_function.cpp
new file mode 100644
index 0000000..e38f2b8
--- /dev/null
+++ b/tests/libs/dlsym_weak_function.cpp
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+extern "C" int __attribute__((weak)) weak_func() {
+ return 42;
+}
+
