[lsan] Add an interface function for on-demand leak checking.

Summary:
Add an interface function which can be used to periodically trigger
leak detection in a long-running process.

NB: The meaning of the kIgnored tag has been changed to allow easy clean-up
between subsequent leak checks. Previously, this tag was applied to explicitly
ignored (i.e. with __lsan_disable() or __lsan_ignore_object()) chunks *and* any
chunks only reachable from those. With this change, it's only applied to
explicitly ignored chunks.

Reviewers: samsonov

Reviewed By: samsonov

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9159

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@235728 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 6 deletions

diff --git a/include/sanitizer/lsan_interface.h b/include/sanitizer/lsan_interface.h
index 46d2668ce..db017c4de 100644
--- a/include/sanitizer/lsan_interface.h
+++ b/include/sanitizer/lsan_interface.h
@@ -41,14 +41,25 @@ extern "C" {
   void __lsan_register_root_region(const void *p, size_t size);
   void __lsan_unregister_root_region(const void *p, size_t size);
 
-  // Calling this function makes LSan enter the leak checking phase immediately.
-  // Use this if normal end-of-process leak checking happens too late (e.g. if
-  // you have intentional memory leaks in your shutdown code). Calling this
-  // function overrides end-of-process leak checking; it must be called at
-  // most once per process. This function will terminate the process if there
-  // are memory leaks and the exit_code flag is non-zero.
+  // Check for leaks now. This function behaves identically to the default
+  // end-of-process leak check. In particular, it will terminate the process if
+  // leaks are found and the exit_code flag is non-zero.
+  // Subsequent calls to this function will have no effect and end-of-process
+  // leak check will not run. Effectively, end-of-process leak check is moved to
+  // the time of first invocation of this function.
+  // By calling this function early during process shutdown, you can instruct
+  // LSan to ignore shutdown-only leaks which happen later on.
   void __lsan_do_leak_check();
 
+  // Check for leaks now. Returns zero if no leaks have been found or if leak
+  // detection is disabled, non-zero otherwise.
+  // This function may be called repeatedly, e.g. to periodically check a
+  // long-running process. It prints a leak report if appropriate, but does not
+  // terminate the process. It does not affect the behavior of
+  // __lsan_do_leak_check() or the end-of-process leak check, and is not
+  // affected by them.
+  int __lsan_do_recoverable_leak_check();
+
   // The user may optionally provide this function to disallow leak checking
   // for the program it is linked into (if the return value is non-zero). This
   // function must be defined as returning a constant value; any behavior beyond