Return a named error in the result object of an expression with no result

Before we returned an error that was not exposed in the SB API and no useful
error message.  This change returns eExpressionProducedNoResult and an
appropriate error string.

<rdar://problem/44539514>

Differential Revision: https://reviews.llvm.org/D53309

llvm-svn: 344647

3 files changed, 60 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/no-result/Makefile b/lldb/packages/Python/lldbsuite/test/expression_command/no-result/Makefile
new file mode 100644
index 00000000000..50d4ab65a6e
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/no-result/Makefile
@@ -0,0 +1,6 @@
+LEVEL = ../../make
+
+C_SOURCES := main.c
+CFLAGS_EXTRAS += -std=c99
+
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/no-result/TestNoResult.py b/lldb/packages/Python/lldbsuite/test/expression_command/no-result/TestNoResult.py
new file mode 100644
index 00000000000..363b30e4de5
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/no-result/TestNoResult.py
@@ -0,0 +1,45 @@
+"""
+Test that an expression that returns no result returns a sensible error.
+"""
+
+from __future__ import print_function
+
+
+import os
+import time
+import re
+import lldb
+import lldbsuite.test.lldbutil as lldbutil
+from lldbsuite.test.lldbtest import *
+
+
+class TestExprNoResult(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    # If your test case doesn't stress debug info, the
+    # set this to true.  That way it won't be run once for
+    # each debug info format.
+    NO_DEBUG_INFO_TESTCASE = True
+
+    def test_no_result(self):
+        """Run an expression that has no result, check the error."""
+        self.build()
+        self.main_source_file = lldb.SBFileSpec("main.c")
+        self.sample_test()
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+
+    def sample_test(self):
+        (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(self,
+                                   "Set a breakpoint here", self.main_source_file)
+
+        frame = thread.GetFrameAtIndex(0)
+        result = frame.EvaluateExpression("int $x = 10")
+        # No result expressions are considered to fail:
+        self.assertTrue(result.GetError().Fail(), "An expression with no result is a failure.")
+        # But the reason should be eExpressionProducedNoResult
+        self.assertEqual(result.GetError().GetError(), lldb.eExpressionProducedNoResult, 
+                         "But the right kind of failure")
diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/no-result/main.c b/lldb/packages/Python/lldbsuite/test/expression_command/no-result/main.c
new file mode 100644
index 00000000000..8d4e0c4f7be
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/no-result/main.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+
+int
+main()
+{
+  int test_var = 10;
+  printf ("Set a breakpoint here: %d.\n", test_var);
+  return 0;
+}