Use Clang's FixItHints to correct expressions with "trivial" mistakes (e.g. "." for "->".)

This feature is controlled by an expression command option, a target property and the
SBExpressionOptions setting.  FixIt's are only applied to UserExpressions, not UtilityFunctions,
those you have to get right when you make them.

This is just a first stage.  At present the fixits are applied silently.  The next step
is to tell the user about the applied fixit.

<rdar://problem/25351938>

llvm-svn: 264379

3 files changed, 114 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/fixits/Makefile b/lldb/packages/Python/lldbsuite/test/expression_command/fixits/Makefile
new file mode 100644
index 00000000000..7df664ac43e
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/fixits/Makefile
@@ -0,0 +1,12 @@
+LEVEL = ../../make
+
+CXX_SOURCES := main.cpp
+
+# clang-3.5+ outputs FullDebugInfo by default for Darwin/FreeBSD
+# targets.  Other targets do not, which causes this test to fail.
+# This flag enables FullDebugInfo for all targets.
+ifneq (,$(findstring clang,$(CC)))
+  CFLAGS_EXTRAS += -fno-limit-debug-info
+endif
+
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/fixits/TestFixIts.py b/lldb/packages/Python/lldbsuite/test/expression_command/fixits/TestFixIts.py
new file mode 100644
index 00000000000..7f442ab4fe1
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/fixits/TestFixIts.py
@@ -0,0 +1,77 @@
+"""
+Test calling an expression with errors that a FixIt can fix.
+"""
+
+from __future__ import print_function
+
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+class ExprCommandWithFixits(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+
+        self.main_source = "main.cpp"
+        self.main_source_spec = lldb.SBFileSpec (self.main_source)
+
+    @skipUnlessDarwin
+    def test(self):
+        """Test calling a function that throws and ObjC exception."""
+        self.build()
+        self.try_expressions()
+
+    def try_expressions(self):
+        """Test calling expressions with errors that can be fixed by the FixIts."""
+        exe_name = "a.out"
+        exe = os.path.join(os.getcwd(), exe_name)
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, VALID_TARGET)
+
+        breakpoint = target.BreakpointCreateBySourceRegex('Stop here to evaluate expressions',self.main_source_spec)
+        self.assertTrue(breakpoint.GetNumLocations() > 0, VALID_BREAKPOINT)
+
+        # Launch the process, and do not stop at the entry point.
+        process = target.LaunchSimple (None, None, self.get_process_working_directory())
+
+        self.assertTrue(process, PROCESS_IS_VALID)
+
+        # Frame #0 should be at our breakpoint.
+        threads = lldbutil.get_threads_stopped_at_breakpoint (process, breakpoint)
+        
+        self.assertTrue(len(threads) == 1)
+        self.thread = threads[0]
+        
+        options = lldb.SBExpressionOptions()
+        options.SetAutoApplyFixIts(True)
+
+        frame = self.thread.GetFrameAtIndex(0)
+
+        # Try with one error:
+        value = frame.EvaluateExpression("my_pointer.first", options)
+        self.assertTrue(value.IsValid())
+        self.assertTrue(value.GetError().Success())
+        self.assertTrue(value.GetValueAsUnsigned() == 10)
+        
+        # Try with two errors:
+        two_error_expression = "my_pointer.second->a"
+        value = frame.EvaluateExpression(two_error_expression, options)
+        self.assertTrue(value.IsValid())
+        self.assertTrue(value.GetError().Success())
+        self.assertTrue(value.GetValueAsUnsigned() == 20)
+
+        # Now turn off the fixits, and the expression should fail:
+        options.SetAutoApplyFixIts(False)
+        value = frame.EvaluateExpression("two_error_expression", options)
+        self.assertTrue(value.IsValid())
+        self.assertTrue(value.GetError().Fail())
+        
+
diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/fixits/main.cpp b/lldb/packages/Python/lldbsuite/test/expression_command/fixits/main.cpp
new file mode 100644
index 00000000000..371d8333763
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/fixits/main.cpp
@@ -0,0 +1,25 @@
+#include <stdio.h>
+
+struct SubStruct
+{
+  int a;
+  int b;
+};
+
+struct MyStruct
+{
+  int first;
+  struct SubStruct second;
+};
+
+int
+main()
+{
+  struct MyStruct my_struct = {10, {20, 30}};
+  struct MyStruct *my_pointer = &my_struct;
+  printf ("Stop here to evaluate expressions: %d %d %p\n", my_pointer->first, my_pointer->second.a, my_pointer);
+  return 0;
+}
+
+
+