[LLDB] Expose several methods in SBWatchpoint

This patch adds the following methods:

* `GetType()`
* `GetWatchValueKind()`
* `GetWatchSpec()`
* `IsWatchingReads()`
* `IsWatchingWrites()`

These mostly expose methods that `lldb_private::Watchpoint` already
had. Tests are included that exercise these new methods.

The motivation for exposing these are as follows:

* `GetType()` - With this information and the address from a watchpoint
  it is now possible to construct an SBValue from an SBWatchpoint.
  Previously this wasn't possible. The included test case illustrates
  doing this.
* `GetWatchValueKind()` - This allows the caller to determine whether the
  watchpoint is a variable watchpoint or an expression watchpoint. A new
  enum (`WatchpointValueKind`) has been introduced to represent the
  return values. Unfortunately the name `WatchpointKind` was already
  taken.
* `GetWatchSpec()` - This allows (at least for variable watchpoints)
  to use a sensible name for SBValues created from an SBWatchpoint.
* `IsWatchingReads()` - This allow checking if a watchpoint is
  monitoring read accesses.
* `IsWatchingWRites()` - This allow checking if a watchpoint is
  monitoring write accesses.

rdar://105606978

Reviewers: jingham, mib, bulbazord, jasonmolenda, JDevlieghere

Differential Revision: https://reviews.llvm.org/D144937

2 files changed, 55 insertions, 6 deletions

diff --git a/lldb/test/API/python_api/watchpoint/TestSetWatchpoint.py b/lldb/test/API/python_api/watchpoint/TestSetWatchpoint.py
index 1a6f18e..b6ffec3 100644
--- a/lldb/test/API/python_api/watchpoint/TestSetWatchpoint.py
+++ b/lldb/test/API/python_api/watchpoint/TestSetWatchpoint.py
@@ -19,12 +19,24 @@ class SetWatchpointAPITestCase(TestBase):
         # Find the line number to break inside main().
         self.line = line_number(
             self.source, '// Set break point at this line.')
+        self.build()
 
     # Read-write watchpoints not supported on SystemZ
     @expectedFailureAll(archs=['s390x'])
     def test_watch_val(self):
         """Exercise SBValue.Watch() API to set a watchpoint."""
-        self.build()
+        self._test_watch_val(variable_watchpoint=False)
+        pass
+
+    @expectedFailureAll(archs=['s390x'])
+    def test_watch_variable(self):
+        """
+           Exercise some watchpoint APIs when the watchpoint
+           is created as a variable watchpoint.
+        """
+        self._test_watch_val(variable_watchpoint=True)
+
+    def _test_watch_val(self, variable_watchpoint):
         exe = self.getBuildArtifact("a.out")
 
         # Create a target by the debugger.
@@ -50,12 +62,40 @@ class SetWatchpointAPITestCase(TestBase):
         frame0 = thread.GetFrameAtIndex(0)
 
         # Watch 'global' for read and write.
-        value = frame0.FindValue('global', lldb.eValueTypeVariableGlobal)
-        error = lldb.SBError()
-        watchpoint = value.Watch(True, True, True, error)
-        self.assertTrue(value and watchpoint,
+        if variable_watchpoint:
+            # FIXME: There should probably be an API to create a
+            # variable watchpoint.
+            self.runCmd('watchpoint set variable -w read_write -- global')
+            watchpoint = target.GetWatchpointAtIndex(0)
+            self.assertEqual(watchpoint.GetWatchValueKind(),
+                             lldb.eWatchPointValueKindVariable)
+            self.assertEqual(watchpoint.GetWatchSpec(), 'global')
+            # Synthesize an SBValue from the watchpoint
+            watchpoint_addr = lldb.SBAddress(watchpoint.GetWatchAddress(),
+                                             target)
+            value = target.CreateValueFromAddress(
+                watchpoint.GetWatchSpec(),
+                watchpoint_addr, watchpoint.GetType())
+        else:
+            value = frame0.FindValue('global', lldb.eValueTypeVariableGlobal)
+            error = lldb.SBError()
+            watchpoint = value.Watch(True, True, True, error)
+            self.assertTrue(value and watchpoint,
                         "Successfully found the variable and set a watchpoint")
-        self.DebugSBValue(value)
+            self.DebugSBValue(value)
+            self.assertEqual(watchpoint.GetWatchValueKind(),
+                             lldb.eWatchPointValueKindExpression)
+            # FIXME: The spec should probably be '&global' given that the kind
+            # is reported as eWatchPointValueKindExpression. If the kind is
+            # actually supposed to be eWatchPointValueKindVariable then the spec
+            # should probably be 'global'.
+            self.assertEqual(watchpoint.GetWatchSpec(), None)
+
+        self.assertEqual(watchpoint.GetType().GetDisplayTypeName(), 'int32_t')
+        self.assertEqual(value.GetName(), 'global')
+        self.assertEqual(value.GetType(), watchpoint.GetType())
+        self.assertTrue(watchpoint.IsWatchingReads())
+        self.assertTrue(watchpoint.IsWatchingWrites())
 
         # Hide stdout if not running with '-t' option.
         if not self.TraceOn():
diff --git a/lldb/test/API/python_api/watchpoint/watchlocation/TestSetWatchlocation.py b/lldb/test/API/python_api/watchpoint/watchlocation/TestSetWatchlocation.py
index bd4d309..ccf9bf8 100644
--- a/lldb/test/API/python_api/watchpoint/watchlocation/TestSetWatchlocation.py
+++ b/lldb/test/API/python_api/watchpoint/watchlocation/TestSetWatchlocation.py
@@ -64,6 +64,15 @@ class SetWatchlocationAPITestCase(TestBase):
         self.DebugSBValue(value)
         self.DebugSBValue(pointee)
 
+        # Check some API calls return expected values
+        self.assertEqual(watchpoint.GetWatchValueKind(),
+                         lldb.eWatchPointValueKindExpression)
+        # FIXME: The spec should probably be 'g_char_ptr'
+        self.assertEqual(watchpoint.GetWatchSpec(), None)
+        self.assertEqual(watchpoint.GetType().GetDisplayTypeName(), 'char')
+        self.assertFalse(watchpoint.IsWatchingReads())
+        self.assertTrue(watchpoint.IsWatchingWrites())
+
         # Hide stdout if not running with '-t' option.
         if not self.TraceOn():
             self.HideStdout()