[libcxx-commits] [PATCH] D113054: [libcxx][SystemZ][z/OS] Update libcxxabi/src/cxa_exception_storage.cpp to support POSIX(OFF)

[Daniel McIntosh via Phabricator via libcxx-commits]

DanielMcIntosh-IBM created this revision.
DanielMcIntosh-IBM added reviewers: mclow.lists, jroelofs, kledzik, ikudrin, ldionne.
Herald added a subscriber: mgrang.
DanielMcIntosh-IBM requested review of this revision.
Herald added a project: libc++abi.
Herald added a subscriber: libcxx-commits.
Herald added a reviewer: libc++abi.

Stop __cxa_get_globals and __cxa_get_globals_fast from using thread-local storage
when the threading API is disabled.

Also stop test_exception_storage.pass.cpp from spawning threads when the
threading API is disabled.

Depends on D110341 <https://reviews.llvm.org/D110341>, D113048 <https://reviews.llvm.org/D113048>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D113054

Files:
  libcxxabi/src/cxa_exception_storage.cpp
  libcxxabi/test/test_exception_storage.pass.cpp


Index: libcxxabi/test/test_exception_storage.pass.cpp
===================================================================
--- libcxxabi/test/test_exception_storage.pass.cpp
+++ libcxxabi/test/test_exception_storage.pass.cpp
@@ -42,33 +42,40 @@
 #endif
 
 int main() {
-#ifndef _LIBCXXABI_HAS_NO_THREADS
-//  Make the threads, let them run, and wait for them to finish
-    for ( int i = 0; i < NUMTHREADS; ++i )
-        std::__libcpp_thread_create ( threads + i, thread_code, (void *) (thread_globals + i));
-    for ( int i = 0; i < NUMTHREADS; ++i )
-        std::__libcpp_thread_join ( &threads [ i ] );
+#ifdef _LIBCXXABI_HAS_NO_THREADS
+  size_t thread_globals;
+  thread_code(&thread_globals);
+  // Check that __cxa_get_globals() is not NULL.
+  return (thread_globals == 0) ? 1 : 0;
+#else  // !_LIBCXXABI_HAS_NO_THREADS
+  // If threads are disabled at runtime, revert to single-threaded test.
+  if (!std::__libcpp_are_threads_enabled()) {
+    thread_code((void*)thread_globals);
+    // Check that __cxa_get_globals() is not NULL.
+    return (thread_globals[0] == 0) ? 1 : 0;
+  }
 
-    int retVal = 0;
-    for ( int i = 0; i < NUMTHREADS; ++i ) {
-        if ( 0 == thread_globals [ i ] ) {
-            std::printf("Thread #%d had a zero global\n", i);
-            retVal = 1;
-        }
+  //  Make the threads, let them run, and wait for them to finish
+  for (int i = 0; i < NUMTHREADS; ++i)
+    std::__libcpp_thread_create(threads + i, thread_code, (void*)(thread_globals + i));
+  for (int i = 0; i < NUMTHREADS; ++i)
+    std::__libcpp_thread_join(&threads[i]);
+
+  int retVal = 0;
+  for (int i = 0; i < NUMTHREADS; ++i) {
+    if (0 == thread_globals[i]) {
+      std::printf("Thread #%d had a zero global\n", i);
+      retVal = 1;
     }
+  }
 
-    std::sort ( thread_globals, thread_globals + NUMTHREADS );
-    for ( int i = 1; i < NUMTHREADS; ++i ) {
-        if ( thread_globals [ i - 1 ] == thread_globals [ i ] ) {
-            std::printf("Duplicate thread globals (%d and %d)\n", i-1, i);
-            retVal = 2;
-        }
+  std::sort(thread_globals, thread_globals + NUMTHREADS);
+  for (int i = 1; i < NUMTHREADS; ++i) {
+    if (thread_globals[i - 1] == thread_globals[i]) {
+      std::printf("Duplicate thread globals (%d and %d)\n", i - 1, i);
+      retVal = 2;
     }
-    return retVal;
-#else // _LIBCXXABI_HAS_NO_THREADS
-    size_t thread_globals;
-    thread_code(&thread_globals);
-    // Check that __cxa_get_globals() is not NULL.
-    return (thread_globals == 0) ? 1 : 0;
+  }
+  return retVal;
 #endif // !_LIBCXXABI_HAS_NO_THREADS
 }
Index: libcxxabi/src/cxa_exception_storage.cpp
===================================================================
--- libcxxabi/src/cxa_exception_storage.cpp
+++ libcxxabi/src/cxa_exception_storage.cpp
@@ -92,10 +92,16 @@
     // to the Itanium ABI and is taken advantage of in several places in
     // libc++abi.
     __cxa_eh_globals *__cxa_get_globals_fast() {
-        // First time through, create the key.
-        if (0 != std::__libcpp_execute_once(&flag_, construct_))
-            abort_message("execute once failure in __cxa_get_globals_fast()");
-        return static_cast<__cxa_eh_globals*>(std::__libcpp_tls_get(key_));
+      // If threads are disabled at runtime, revert to single-threaded implementation.
+      static const bool threadsEnabled = std::__libcpp_are_threads_enabled();
+      if (!threadsEnabled) {
+        static __cxa_eh_globals eh_globals;
+        return &eh_globals;
+      }
+      // First time through, create the key.
+      if (0 != std::__libcpp_execute_once(&flag_, construct_))
+        abort_message("execute once failure in __cxa_get_globals_fast()");
+      return static_cast<__cxa_eh_globals*>(std::__libcpp_tls_get(key_));
     }
 } // extern "C"
 } // namespace __cxxabiv1


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