[TSan][Darwin] Add integration tests for dyld interposition

[yln]

Summary

Add integration tests for dyld interposition: DYLD_LIBRARY_PATH and
DYLD_INSERT_LIBRARIES.

DYLD_INSERT_LIBRARIES is also relevant for TSan thread
finalization/destruction sequence in the presence of additional pthread
introspection hooks (libBacktraceRecording.dylib for Xcode 'Queue
Debugging' feature).

rdar://78739125

[delcypher]

compiler-rt/test/tsan/Darwin/dyld-insert-libraries.c

46

Maybe note that the "injected library constructor" that you're talking about is __library_initializer?

47

Maybe

constructors (DYLD_INSERT_LIBRARIES) run after the TSan initializer, which replaces and forwards to the previous pthread_introspection hook.

?

[delcypher]

LGTM with some very minor nits.

[yln]

Improve comments and commit message.

compiler-rt/test/tsan/Darwin/dyld-insert-libraries.c

+// Test that dyld interposition works in the presence of DYLD_INSERT_LIBRARIES.
+// Additionally, the injected library also has a pthread introspection hook that
+// calls intercepted APIs before and after calling through to the TSan hook.
+// This mirrors what libBacktraceRecording.dylib (Xcode 'Queue Debugging'
+// feature) does.
+
+// RUN: %clang_tsan %s -o %t
+// RUN: %clang_tsan %s -o %t.dylib -fno-sanitize=thread -dynamiclib -DSHARED_LIB
+//
+// RUN: env DYLD_INSERT_LIBRARIES=%t.dylib %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer'
+//
+// XFAIL: ios
+
+#include <assert.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(SHARED_LIB)
+enum {
+  PTHREAD_INTROSPECTION_THREAD_CREATE = 1,
+  PTHREAD_INTROSPECTION_THREAD_START,
+  PTHREAD_INTROSPECTION_THREAD_TERMINATE,
+  PTHREAD_INTROSPECTION_THREAD_DESTROY,
+};
+typedef void (*pthread_introspection_hook_t)(unsigned int event,
+                                             pthread_t thread, void *addr,
+                                             size_t size);
+extern pthread_introspection_hook_t pthread_introspection_hook_install(
+    pthread_introspection_hook_t hook);
+
+static pthread_introspection_hook_t previous_pthread_hook;
+static void pthread_introspection_hook(unsigned int event, pthread_t thread, void *addr, size_t size) {
+  pthread_t self;
+  const unsigned k_max_thread_name_size = 64;
+  char name[k_max_thread_name_size];
+
+  // Use some intercepted APIs *before* TSan hook runs.
+  {
+    self = pthread_self();
+    pthread_getname_np(self, name, k_max_thread_name_size);
+    if (strlen(name) == 0) {
+      strlcpy(name, "n/a", 4);
+    }
+  }
+
+  // This calls through to the TSan-installed hook, because the injected library
+  // constructor (see __library_initializer() below) runs after the TSan
+  // initializer.  It replaces and forward to the previously-installed TSan
+  // introspection hook (very similar to what libBacktraceRecording.dylib does).
+  assert(previous_pthread_hook);
+  previous_pthread_hook(event, thread, addr, size);
+
+  // Use some intercepted APIs *after* TSan hook runs.
+  {
+    assert(self == pthread_self());
+    char name2[k_max_thread_name_size];
+    pthread_getname_np(self, name2, k_max_thread_name_size);
+    if (strlen(name2) == 0) {
+      strlcpy(name2, "n/a", 4);
+    }
+    assert(strcmp(name, name2) == 0);
+  }
+
+  switch (event) {
+  case PTHREAD_INTROSPECTION_THREAD_CREATE:
+    fprintf(stderr, "THREAD_CREATE    %p, self: %p, name: %s\n", thread, self, name);
+    break;
+  case PTHREAD_INTROSPECTION_THREAD_START:
+    fprintf(stderr, "THREAD_START     %p, self: %p, name: %s\n", thread, self, name);
+    break;
+  case PTHREAD_INTROSPECTION_THREAD_TERMINATE:
+    fprintf(stderr, "THREAD_TERMINATE %p, self: %p, name: %s\n", thread, self, name);
+    break;
+  case PTHREAD_INTROSPECTION_THREAD_DESTROY:
+    fprintf(stderr, "THREAD_DESTROY   %p, self: %p, name: %s\n", thread, self, name);
+    break;
+  }
+}
+
+__attribute__((constructor))
+static void __library_initializer(void) {
+  fprintf(stderr, "__library_initializer\n");
+  previous_pthread_hook = pthread_introspection_hook_install(pthread_introspection_hook);
+}
+
+#else  // defined(SHARED_LIB)
+
+void *Thread(void *a) {
+  pthread_setname_np("child thread");
+  fprintf(stderr, "Hello from pthread\n");
+  return NULL;
+}
+
+int main() {
+  fprintf(stderr, "main\n");
+  pthread_t t;
+  pthread_create(&t, NULL, Thread, NULL);
+  pthread_join(t, NULL);
+  fprintf(stderr, "Done.\n");
+}
+#endif  // defined(SHARED_LIB)
+
+// CHECK: __library_initializer
+// CHECK: main
+// Ignore TSan background thread.
+// CHECK: THREAD_CREATE
+// CHECK: THREAD_CREATE    [[CHILD:0x[0-9a-f]+]], self: [[MAIN:0x[0-9a-f]+]], name: n/a
+// CHECK: THREAD_START     [[CHILD]], self: [[CHILD]], name: n/a
+// CHECK: Hello from pthread
+// CHECK: THREAD_TERMINATE [[CHILD]], self: [[CHILD]], name: child thread
+// CHECK: THREAD_DESTROY   [[CHILD]], self: [[MAIN]]
+// CHECK: Done.

compiler-rt/test/tsan/Darwin/dyld-library-path.c

+// Test that dyld interposition works in the presence of DYLD_LIBRARY_PATH.
+
+// RUN: %clang_tsan %s -o %t
+// RUN: env DYLD_LIBRARY_PATH=/usr/lib/system/introspection/ %run %t 2>&1 | FileCheck %s --implicit-check-not='ThreadSanitizer'
+
+#include <pthread.h>
+#include <stdio.h>
+
+void *Thread(void *a) {
+  fprintf(stderr, "Hello from pthread\n");
+  return NULL;
+}
+
+int main() {
+  pthread_t t;
+  pthread_create(&t, NULL, Thread, NULL);
+  pthread_join(t, NULL);
+  fprintf(stderr, "Done.\n");
+}
+
+// CHECK: Hello from pthread
+// CHECK: Done.