[asan] Move __asan_handle_no_return to public header

Heretofore asan_handle_no_return was used only by interceptors,
i.e. code private to the ASan runtime. However, on systems without
interceptors, code like libc++abi is built with -fsanitize=address
itself and should call asan_handle_no_return directly from
__cxa_throw so that no interceptor is required.

Patch by Roland McGrath

Differential Revision: https://reviews.llvm.org/D36811

llvm-svn: 311869

compiler-rt/include/sanitizer/asan_interface.h

@@ -144,6 +144,10 @@ extern "C" {
   void *__asan_addr_is_in_fake_stack(void *fake_stack, void *addr, void **beg,
                                      void **end);
 
+  // Performs cleanup before a [[noreturn]] function.  Must be called
+  // before things like _exit and execl to avoid false positives on stack.
+  void __asan_handle_no_return(void);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif

compiler-rt/lib/asan/tests/asan_interface_test.cc

@@ -423,3 +423,11 @@ TEST(AddressSanitizerInterface, GetOwnershipStressTest) {
     free(pointers[i]);
 }
 
+TEST(AddressSanitizerInterface, HandleNoReturnTest) {
+  char array[40];
+  __asan_poison_memory_region(array, sizeof(array));
+  BAD_ACCESS(array, 20);
+  __asan_handle_no_return();
+  // It unpoisons the whole thread stack.
+  GOOD_ACCESS(array, 20);
+}