[lldb] Improve the error message in run_to_breakpoint_do_run

Improve the error message when we fail to hit the initial breakpoint in
run_to_breakpoint_do_run. In addition to the process state, we now also
report the exit code and reason (if the process exited) as well as the
inferior's output.

Differential revision: https://reviews.llvm.org/D111978

lldb/packages/Python/lldbsuite/test/lldbutil.py

@@ -235,7 +235,7 @@ def state_type_to_str(enum):
     elif enum == lldb.eStateSuspended:
         return "suspended"
     else:
-        raise Exception("Unknown StateType enum")
+        raise Exception("Unknown StateType enum: " + str(enum))
 
 
 def stop_reason_to_str(enum):
@@ -945,7 +945,22 @@ def run_to_breakpoint_do_run(test, target, bkpt, launch_info = None,
     test.assertFalse(error.Fail(),
                      "Process launch failed: %s" % (error.GetCString()))
 
-    test.assertState(process.GetState(), lldb.eStateStopped)
+    def processStateInfo(process):
+        info = "state: {}".format(state_type_to_str(process.state))
+        if process.state == lldb.eStateExited:
+            info += ", exit code: {}".format(process.GetExitStatus())
+            if process.exit_description:
+                info += ", exit description: '{}'".format(process.exit_description)
+        stdout = process.GetSTDOUT(999)
+        if stdout:
+            info += ", stdout: '{}'".format(stdout)
+        stderr = process.GetSTDERR(999)
+        if stderr:
+            info += ", stderr: '{}'".format(stderr)
+        return info
+
+    if process.state != lldb.eStateStopped:
+        test.fail("Test process is not stopped at breakpoint: {}".format(processStateInfo(process)))
 
     # Frame #0 should be at our breakpoint.
     threads = get_threads_stopped_at_breakpoint(

lldb/test/API/lldbutil-tests/failed-to-hit-breakpoint/Makefile

@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules

lldb/test/API/lldbutil-tests/failed-to-hit-breakpoint/TestLLDBUtilFailedToHitBreakpoint.py

@@ -0,0 +1,27 @@
+"""
+Tests lldbutil's behavior when running to a source breakpoint fails.
+"""
+
+import lldb
+import lldbsuite.test.lldbutil as lldbutil
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+
+
+class LLDBUtilFailedToHitBreakpointTest(TestBase):
+
+    NO_DEBUG_INFO_TESTCASE = True
+
+    @expectedFailureAll(oslist=["windows"])
+    def test_error_message(self):
+        """
+        Tests that run_to_source_breakpoint prints the right error message
+        when failing to hit the wanted breakpoint.
+        """
+        self.build()
+        with self.assertRaisesRegex(
+                AssertionError,
+                "Test process is not stopped at breakpoint: state: exited, exit code: 0, stdout: 'stdout_needlestderr_needle'"
+        ):
+            lldbutil.run_to_source_breakpoint(self, "// break here",
+                                              lldb.SBFileSpec("main.cpp"))

lldb/test/API/lldbutil-tests/failed-to-hit-breakpoint/main.cpp

@@ -0,0 +1,21 @@
+#include <iostream>
+#include <thread>
+
+int main(int argc, char **argv) {
+  // Print the string that the test looks for to make sure stdout and stderr
+  // got recorded.
+  std::cout << "stdout_needle" << std::flush;
+  std::cerr << "stderr_needle" << std::flush;
+
+  // Work around a timing issue that sometimes prevents stderr from being
+  // captured.
+  std::this_thread::sleep_for(std::chrono::seconds(1));
+
+  // This is unreachable during normal test execution as we don't pass any
+  // (or +100) arguments. This still needs to be theoretically reachable code
+  // so that the compiler will generate code for this (that we can set a
+  // breakpoint on).
+  if (argc > 100)
+    return 1; // break here
+  return 0;
+}