Improve sanitizer detection

__has_feature(leak_sanitizer) cannot be used to detect the existence of LSan.

Author: kleisauke

system/include/emscripten/bind.h

@@ -21,7 +21,7 @@
 #include <emscripten/val.h>
 #include <emscripten/wire.h>
 
-#if __has_feature(leak_sanitizer) || __has_feature(address_sanitizer)
+#if defined(HAS_LSAN) || __has_feature(address_sanitizer)
 #include <sanitizer/lsan_interface.h>
 #endif
 
@@ -604,7 +604,7 @@ template<typename T>
 inline T* getContext(const T& t) {
     // not a leak because this is called once per binding
     auto* ret = new T(t);
-#if __has_feature(leak_sanitizer) || __has_feature(address_sanitizer)
+#if defined(HAS_LSAN) || __has_feature(address_sanitizer)
     __lsan_ignore_object(ret);
 #endif
     return ret;

system/lib/pthread/library_pthread.c

@@ -139,19 +139,16 @@ extern double emscripten_receive_on_main_thread_js(int functionIndex, int numCal
 extern int _emscripten_notify_thread_queue(pthread_t targetThreadId, pthread_t mainThreadId);
 extern int __pthread_create_js(struct pthread *thread, const pthread_attr_t *attr, void *(*start_routine) (void *), void *arg);
 
-#if defined(__has_feature)
-#if __has_feature(leak_sanitizer) || __has_feature(address_sanitizer)
-#define HAS_SANITIZER
+#if defined(HAS_LSAN) || __has_feature(address_sanitizer)
 #include <sanitizer/lsan_interface.h>
 #endif
-#endif
 
 static void _do_call(em_queued_call* q) {
   // C function pointer
   assert(EM_FUNC_SIG_NUM_FUNC_ARGUMENTS(q->functionEnum) <= EM_QUEUED_CALL_MAX_ARGS);
   switch (q->functionEnum) {
     case EM_PROXIED_PTHREAD_CREATE:
-#ifdef HAS_SANITIZER
+#if defined(HAS_LSAN) || __has_feature(address_sanitizer)
       // ASan wraps the emscripten_builtin_pthread_create call in __lsan::ScopedInterceptorDisabler.
       // Unfortunately, that only disables it on the thread that made the call.
       // This is sufficient on the main thread.
@@ -163,7 +160,7 @@ static void _do_call(em_queued_call* q) {
 #endif
       q->returnValue.i =
         __pthread_create_js(q->args[0].vp, q->args[1].vp, q->args[2].vp, q->args[3].vp);
-#ifdef HAS_SANITIZER
+#if defined(HAS_LSAN) || __has_feature(address_sanitizer)
       __lsan_enable();
 #endif
       break;

tools/system_libs.py

@@ -670,6 +670,32 @@ def get_default_variation(cls, **kwargs):
     return super().get_default_variation(is_asan=settings.USE_ASAN, **kwargs)
 
 
+class LsanInstrumentedLibrary(Library):
+  def __init__(self, **kwargs):
+    self.is_lsan = kwargs.pop('is_lsan', False)
+    super().__init__(**kwargs)
+
+  def get_cflags(self):
+    cflags = super().get_cflags()
+    if self.is_lsan:
+      cflags += ['-fsanitize=leak', '-DHAS_LSAN']
+    return cflags
+
+  def get_base_name(self):
+    name = super().get_base_name()
+    if self.is_lsan:
+      name += '-lsan'
+    return name
+
+  @classmethod
+  def vary_on(cls):
+    return super().vary_on() + ['is_lsan']
+
+  @classmethod
+  def get_default_variation(cls, **kwargs):
+    return super().get_default_variation(is_lsan=settings.USE_LSAN, **kwargs)
+
+
 class libcompiler_rt(MTLibrary):
   name = 'libcompiler_rt'
   # compiler_rt files can't currently be part of LTO although we are hoping to remove this
@@ -690,7 +716,7 @@ class libcompiler_rt(MTLibrary):
       ])
 
 
-class libc(AsanInstrumentedLibrary, MuslInternalLibrary, MTLibrary):
+class libc(AsanInstrumentedLibrary, LsanInstrumentedLibrary, MuslInternalLibrary, MTLibrary):
   name = 'libc'
 
   # Without -fno-builtin, LLVM can optimize away or convert calls to library