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// RUN: %clangxx_tsan -O1 %s -DBUILD_SO -fPIC -shared -o %t-so.so
// RUN: %clangxx_tsan -O1 %s %link_libcxx_tsan -o %t && %run %t 2>&1 | FileCheck %s
// A test for loading a dynamic library with static TLS.
// Such static TLS is a hack that allows a dynamic library to have faster TLS,
// but it can be loaded only iff all threads happened to allocate some excess
// of static TLS space for whatever reason. If it's not the case loading fails with:
// dlopen: cannot load any more object with static TLS
// We used to produce a false positive because dlopen will write into TLS
// of all existing threads to initialize/zero TLS region for the loaded library.
// And this appears to be racing with initialization of TLS in the thread
// since we model a write into the whole static TLS region (we don't know what part
// of it is currently unused):
// WARNING: ThreadSanitizer: data race (pid=2317365)
// Write of size 1 at 0x7f1fa9bfcdd7 by main thread:
// #0 memset
// #1 init_one_static_tls
// #2 __pthread_init_static_tls
// [[ this is where main calls dlopen ]]
// #3 main
// Previous write of size 8 at 0x7f1fa9bfcdd0 by thread T1:
// #0 __tsan_tls_initialization
// Failing on bots:
// https://lab.llvm.org/buildbot#builders/184/builds/1580
// https://lab.llvm.org/buildbot#builders/18/builds/3167
// UNSUPPORTED: target={{(aarch64|powerpc64).*}}
#ifdef BUILD_SO
__attribute__((tls_model("initial-exec"))) __thread char x = 42;
__attribute__((tls_model("initial-exec"))) __thread char y;
extern "C" int sofunc() { return ++x + ++y; }
#else // BUILD_SO
# include "../test.h"
# include <dlfcn.h>
# include <string>
__thread int x[1023];
void *lib;
void (*func)();
int ready;
void *thread(void *arg) {
barrier_wait(&barrier);
if (__atomic_load_n(&ready, __ATOMIC_ACQUIRE))
func();
barrier_wait(&barrier);
if (dlclose(lib)) {
printf("error in dlclose: %s\n", dlerror());
exit(1);
}
return 0;
}
int main(int argc, char *argv[]) {
barrier_init(&barrier, 2);
pthread_t th;
pthread_create(&th, 0, thread, 0);
lib = dlopen((std::string(argv[0]) + "-so.so").c_str(), RTLD_NOW);
if (lib == 0) {
printf("error in dlopen: %s\n", dlerror());
return 1;
}
func = (void (*)())dlsym(lib, "sofunc");
if (func == 0) {
printf("error in dlsym: %s\n", dlerror());
return 1;
}
__atomic_store_n(&ready, 1, __ATOMIC_RELEASE);
barrier_wait(&barrier);
func();
barrier_wait(&barrier);
pthread_join(th, 0);
fprintf(stderr, "DONE\n");
return 0;
}
#endif // BUILD_SO
// CHECK: DONE
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