Extend synthetic children to produce synthetic values (as in, those that GetValueAsUnsigned(), GetValueAsCString() would return)

The way to do this is to write a synthetic child provider for your type, and have it vend the (optional) get_value function.
If get_value is defined, and it returns a valid SBValue, that SBValue's value (as in lldb_private::Value) will be used as the synthetic ValueObject's Value

The rationale for doing things this way is twofold:

- there are many possible ways to define a "value" (SBData, a Python number, ...) but SBValue seems general enough as a thing that stores a "value", so we just trade values that way and that keeps our currency trivial
- we could introduce a new level of layering (ValueObjectSyntheticValue), a new kind of formatter (synthetic value producer), but that would complicate the model (can I have a dynamic with no synthetic children but synthetic value? synthetic value with synthetic children but no dynamic?), and I really couldn't see much benefit to be reaped from this added complexity in the matrix
On the other hand, just defining a synthetic child provider with a get_value but returning no actual children is easy enough that it's not a significant road-block to adoption of this feature

Comes with a test case

llvm-svn: 219330

1 files changed, 95 insertions, 0 deletions

diff --git a/lldb/test/functionalities/data-formatter/data-formatter-synthval/TestDataFormatterSynthVal.py b/lldb/test/functionalities/data-formatter/data-formatter-synthval/TestDataFormatterSynthVal.py
new file mode 100644
index 00000000000..c5ff06b04b4
--- /dev/null
+++ b/lldb/test/functionalities/data-formatter/data-formatter-synthval/TestDataFormatterSynthVal.py
@@ -0,0 +1,95 @@
+"""
+Test lldb data formatter subsystem.
+"""
+
+import os, time
+import unittest2
+import lldb
+from lldbtest import *
+import lldbutil
+
+class DataFormatterSynthValueTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    @unittest2.skipUnless(sys.platform.startswith("darwin"), "requires Darwin")
+    @dsym_test
+    def test_with_dsym_and_run_command(self):
+        """Test using Python synthetic children provider to provide a value."""
+        self.buildDsym()
+        self.data_formatter_commands()
+
+    @skipIfFreeBSD # llvm.org/pr20545 bogus output confuses buildbot parser
+    @dwarf_test
+    def test_with_dwarf_and_run_command(self):
+        """Test using Python synthetic children provider to provide a value."""
+        self.buildDwarf()
+        self.data_formatter_commands()
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+        # Find the line number to break at.
+        self.line = line_number('main.cpp', 'break here')
+
+    def data_formatter_commands(self):
+        """Test using Python synthetic children provider to provide a value."""
+        self.runCmd("file a.out", CURRENT_EXECUTABLE_SET)
+
+        lldbutil.run_break_set_by_file_and_line (self, "main.cpp", self.line, num_expected_locations=1, loc_exact=True)
+
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        # The stop reason of the thread should be breakpoint.
+        self.expect("thread list", STOPPED_DUE_TO_BREAKPOINT,
+            substrs = ['stopped',
+                       'stop reason = breakpoint'])
+
+        # This is the function to remove the custom formats in order to have a
+        # clean slate for the next test case.
+        def cleanup():
+            self.runCmd('type format clear', check=False)
+            self.runCmd('type summary clear', check=False)
+            self.runCmd('type filter clear', check=False)
+            self.runCmd('type synth clear', check=False)
+
+        # Execute the cleanup function during test case tear down.
+        self.addTearDownHook(cleanup)
+        
+        x = self.frame().FindVariable("x")
+        x.SetPreferSyntheticValue(True)
+        y = self.frame().FindVariable("y")
+        y.SetPreferSyntheticValue(True)
+        z = self.frame().FindVariable("z")
+        z.SetPreferSyntheticValue(True)
+
+        x_val = x.GetValueAsUnsigned
+        y_val = y.GetValueAsUnsigned
+        z_val = z.GetValueAsUnsigned
+        
+        if self.TraceOn():
+            print "x_val = %s; y_val = %s; z_val = %s" % (x_val(),y_val(),z_val())
+
+        self.assertFalse(x_val() == 3, "x == 3 before synthetics")
+        self.assertFalse(y_val() == 4, "y == 4 before synthetics")
+        self.assertFalse(z_val() == 7, "z == 7 before synthetics")
+
+        # now set up the synth
+        self.runCmd("script from myIntSynthProvider import *")
+        self.runCmd("type synth add -l myIntSynthProvider myInt")
+        
+        if self.TraceOn():
+            print "x_val = %s; y_val = %s; z_val = %s" % (x_val(),y_val(),z_val())
+        
+        self.assertTrue(x_val() == 3, "x != 3 after synthetics")
+        self.assertTrue(y_val() == 4, "y != 4 after synthetics")
+        self.assertTrue(z_val() == 7, "z != 7 after synthetics")
+        
+        self.expect("frame variable x", substrs=['3'])
+        self.expect("frame variable x", substrs=['theValue = 3'], matching=False)
+
+if __name__ == '__main__':
+    import atexit
+    lldb.SBDebugger.Initialize()
+    atexit.register(lambda: lldb.SBDebugger.Terminate())
+    unittest2.main()