Make sure TestNumThreads works with libc++

The problem was that with libc++ the std::unique_lock declaration was
completely inlined, so there was no line table entry in the main.cpp
file to set a breakpoint on. Therefore, the breakpoint got moved to the
next line, but that meant the test would deadlock as the thread would
stop with the lock already held.

I fix that issue by adding a dummy statement before the std::unique_lock
line to anchor the breakpoint.

I think this should fix the issue because of which this test was
disabled on darwin, but someone should verify that before enabling it.

llvm-svn: 335132

2 files changed, 6 insertions, 2 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/TestNumThreads.py b/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/TestNumThreads.py
index 663464346a2..4c4e645635c 100644
--- a/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/TestNumThreads.py
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/TestNumThreads.py
@@ -16,13 +16,14 @@ import lldbsuite.test.lldbutil as lldbutil
 class NumberOfThreadsTestCase(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
+    NO_DEBUG_INFO_TESTCASE = True
 
     def setUp(self):
         # Call super's setUp().
         TestBase.setUp(self)
         # Find the line numbers for our break points.
         self.thread3_notify_all_line = line_number('main.cpp', '// Set thread3 break point on notify_all at this line.')
-        self.thread3_before_lock_line = line_number('main.cpp', '// Set thread3 break point on lock at this line.')
+        self.thread3_before_lock_line = line_number('main.cpp', '// thread3-before-lock')
 
     def test_number_of_threads(self):
         """Test number of threads."""
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/main.cpp b/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/main.cpp
index 42a07f35303..fdc060d135d 100644
--- a/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/main.cpp
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/thread/num_threads/main.cpp
@@ -12,7 +12,10 @@ void *
 thread3(void *input)
 {
     pseudo_barrier_wait(thread3_barrier);
-    std::unique_lock<std::mutex> lock(mutex); // Set thread3 break point on lock at this line.
+
+    int dummy = 47; // thread3-before-lock
+
+    std::unique_lock<std::mutex> lock(mutex); 
     cond.notify_all(); // Set thread3 break point on notify_all at this line.
     return NULL;
 }