According to the GCC documentation (look at https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html) "the order in which constructors for C++ objects with static storage duration and functions decorated with attribute constructor are invoked is unspecified". This means that for example using std::cout in the function with a constructor attribute is dangerous as the std::cout (global object) may have not been initialized yet (see this bug report for better explanation - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94810).
The test tst-tls.cc compiled as PIE includes assertions executed as part of the before_main() function which is annotated with a constructor attribute and gets called before the regular main. The before_main() calls report() function which uses std::cout to print assertion result. This happens to work fine when OSv exports all symbols including the stdc++ ones like std::cout which is initialized by then, but crashes miserably on Linux and OSv with most symbols and stdc++ hidden. This patch fixes the test to make it work correctly in all cases by changing report() function to use std::cout or printf() depending on where in the program lifecycle it is called. Signed-off-by: Waldemar Kozaczuk <[email protected]> --- tests/tst-tls.cc | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/tests/tst-tls.cc b/tests/tst-tls.cc index 58154382..da09ca1e 100644 --- a/tests/tst-tls.cc +++ b/tests/tst-tls.cc @@ -50,11 +50,15 @@ __thread int v10 __attribute__ ((tls_model ("local-exec"))) = 1111; extern void external_library(); -static void report(bool ok, std::string msg) +static void report(bool ok, std::string msg, bool use_printf = false) { ++tests; fails += !ok; - std::cout << (ok ? "PASS" : "FAIL") << ": " << msg << "\n"; + if (use_printf) { + printf("%s: %s\n", ok ? "PASS" : "FAIL", msg.c_str()); + } else { + std::cout << (ok ? "PASS" : "FAIL") << ": " << msg << "\n"; + } } int main(int argc, char** argv) @@ -124,8 +128,8 @@ int main(int argc, char** argv) static void before_main(void) __attribute__((constructor)); static void before_main(void) { - report(v7 == 987UL, "v7 in init function"); - report(v9 == 0, "v8 in init function"); + report(v7 == 987UL, "v7 in init function", true); + report(v9 == 0, "v8 in init function", true); } #endif -- 2.31.1 -- You received this message because you are subscribed to the Google Groups "OSv Development" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/osv-dev/20220109011732.903007-1-jwkozaczuk%40gmail.com.
