Imported Upstream version 6.10.0.49

Former-commit-id: 1d6753294b2993e1fbf92de9366bb9544db4189b

external/llvm-project/lldb/packages/Python/lldbsuite/test/functionalities/expr-doesnt-deadlock/.categories

@@ -0,0 +1 @@
+expression

external/llvm-project/lldb/packages/Python/lldbsuite/test/functionalities/expr-doesnt-deadlock/Makefile

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+LEVEL = ../../make
+
+C_SOURCES := locking.c
+ENABLE_THREADS := YES
+
+include $(LEVEL)/Makefile.rules

external/llvm-project/lldb/packages/Python/lldbsuite/test/functionalities/expr-doesnt-deadlock/TestExprDoesntBlock.py

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+"""
+Test that expr will time out and allow other threads to run if it blocks.
+"""
+
+from __future__ import print_function
+
+
+import os
+import time
+import re
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class ExprDoesntDeadlockTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @expectedFailureAll(oslist=['freebsd'], bugnumber='llvm.org/pr17946')
+    @expectedFailureAll(
+        oslist=["windows"],
+        bugnumber="Windows doesn't have pthreads, test needs to be ported")
+    @add_test_categories(["basic_process"])
+    def test_with_run_command(self):
+        """Test that expr will time out and allow other threads to run if it blocks."""
+        self.build()
+        exe = os.path.join(os.getcwd(), "a.out")
+
+        # Create a target by the debugger.
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, VALID_TARGET)
+
+        # Now create a breakpoint at source line before call_me_to_get_lock
+        # gets called.
+
+        main_file_spec = lldb.SBFileSpec("locking.c")
+        breakpoint = target.BreakpointCreateBySourceRegex(
+            'Break here', main_file_spec)
+        if self.TraceOn():
+            print("breakpoint:", breakpoint)
+        self.assertTrue(breakpoint and
+                        breakpoint.GetNumLocations() == 1,
+                        VALID_BREAKPOINT)
+
+        # Now launch the process, and do not stop at entry point.
+        process = target.LaunchSimple(
+            None, None, self.get_process_working_directory())
+        self.assertTrue(process, PROCESS_IS_VALID)
+
+        # Frame #0 should be on self.line1 and the break condition should hold.
+        from lldbsuite.test.lldbutil import get_stopped_thread
+        thread = get_stopped_thread(process, lldb.eStopReasonBreakpoint)
+        self.assertTrue(
+            thread.IsValid(),
+            "There should be a thread stopped due to breakpoint condition")
+
+        frame0 = thread.GetFrameAtIndex(0)
+
+        var = frame0.EvaluateExpression("call_me_to_get_lock()")
+        self.assertTrue(var.IsValid())
+        self.assertTrue(var.GetValueAsSigned(0) == 567)

external/llvm-project/lldb/packages/Python/lldbsuite/test/functionalities/expr-doesnt-deadlock/locking.c

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+#include <pthread.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+
+pthread_mutex_t contended_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+pthread_mutex_t control_mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t  control_condition;
+
+pthread_mutex_t thread_started_mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t  thread_started_condition;
+
+// This function runs in a thread.  The locking dance is to make sure that 
+// by the time the main thread reaches the pthread_join below, this thread
+// has for sure acquired the contended_mutex.  So then the call_me_to_get_lock
+// function will block trying to get the mutex, and only succeed once it
+// signals this thread, then lets it run to wake up from the cond_wait and
+// release the mutex.
+
+void *
+lock_acquirer_1 (void *input)
+{
+  pthread_mutex_lock (&contended_mutex);
+  
+  // Grab this mutex, that will ensure that the main thread
+  // is in its cond_wait for it (since that's when it drops the mutex.
+
+  pthread_mutex_lock (&thread_started_mutex);
+  pthread_mutex_unlock(&thread_started_mutex);
+
+  // Now signal the main thread that it can continue, we have the contended lock
+  // so the call to call_me_to_get_lock won't make any progress till  this
+  // thread gets a chance to run.
+
+  pthread_mutex_lock (&control_mutex);
+
+  pthread_cond_signal (&thread_started_condition);
+
+  pthread_cond_wait (&control_condition, &control_mutex);
+
+  pthread_mutex_unlock (&contended_mutex);
+  return NULL;
+}
+
+int
+call_me_to_get_lock ()
+{
+  pthread_cond_signal (&control_condition);
+  pthread_mutex_lock (&contended_mutex);
+  return 567;
+}
+
+int main ()
+{
+  pthread_t thread_1;
+
+  pthread_cond_init (&control_condition, NULL);
+  pthread_cond_init (&thread_started_condition, NULL);
+
+  pthread_mutex_lock (&thread_started_mutex);
+
+  pthread_create (&thread_1, NULL, lock_acquirer_1, NULL);
+  
+  pthread_cond_wait (&thread_started_condition, &thread_started_mutex);
+
+  pthread_mutex_lock (&control_mutex);
+  pthread_mutex_unlock (&control_mutex);
+
+  // Break here.  At this point the other thread will have the contended_mutex,
+  // and be sitting in its cond_wait for the control condition.  So there is
+  // no way that our by-hand calling of call_me_to_get_lock will proceed
+  // without running the first thread at least somewhat.
+
+  call_me_to_get_lock();
+  pthread_join (thread_1, NULL);
+
+  return 0;
+
+}