Update dwarf::ApplePropertyAttributes enum to meaningful values.

[friss]

Summary

We currently emit an DW_AT_APPLE_property_attribute with a value that is a
bitfield describing the various attributes applied to an ObjectiveC property.
While trying to add testing to one of my dwarfdump patches that would pretty
print that, I realized this information looks totally broken and has maybe
never been correct.

As with every DWARF info, we have some enum in Dwarf.h that describes this
attribute (enum ApplePropertyAttributes). It seems however that the attribute
value is set from another definition of these flags in Sema/DeclSpec.h (enum
ObjCPropertyAttributeKind). And these 2 enums aren't in sync.

This patch updates the Dwarf.h values to the ones we are (and have been for
a very long time) emitting. We change some publicly (and even documented
in SourceLevelDebugging.rst) values, but I doubt this could be an issue as
the information has been wrong for so long...

[dblaikie]

I'll leave this to Adrian to sign off on, since it's out of my depth in ObjC land, but I can confirm that this enum now matches the other one.

include/llvm/Support/Dwarf.h

784

Crazy idea: Could we do this the other way around, and remove ObjCPropertyAttributeKind in favor of using this enum directly?

Probably not, but figured I'd mention it.

[echristo]

Seems obvious. Thanks.

-eric

[friss]

include/llvm/Support/Dwarf.h

784

I thought of that but I think there would be (rightful) resistance to having Sema code depend on the Dwarf header. In a followup patch for the dwarfdump functionality, I'll try to add coverage for most if not all of these, that will at least prevent us from breaking the current values unknowingly.

[friss]

Closed by commit rL219311 (authored by @friss).

docs/SourceLevelDebugging.rst

 | DW_AT_APPLE_property_setter    | 0x3fea | String    |
 +--------------------------------+--------+-----------+
 | DW_AT_APPLE_property_attribute | 0x3feb | Constant  |
 +--------------------------------+--------+-----------+
 
 New DWARF Constants
 ^^^^^^^^^^^^^^^^^^^
 
-+--------------------------------+-------+
-| Name                           | Value |
-+================================+=======+
-| DW_AT_APPLE_PROPERTY_readonly  | 0x1   |
-+--------------------------------+-------+
-| DW_AT_APPLE_PROPERTY_readwrite | 0x2   |
-+--------------------------------+-------+
-| DW_AT_APPLE_PROPERTY_assign    | 0x4   |
-+--------------------------------+-------+
-| DW_AT_APPLE_PROPERTY_retain    | 0x8   |
-+--------------------------------+-------+
-| DW_AT_APPLE_PROPERTY_copy      | 0x10  |
-+--------------------------------+-------+
-| DW_AT_APPLE_PROPERTY_nonatomic | 0x20  |
-+--------------------------------+-------+
++--------------------------------------+-------+
+| Name                                 | Value |
++======================================+=======+
+| DW_APPLE_PROPERTY_readonly           | 0x01  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_getter             | 0x02  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_assign             | 0x04  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_readwrite          | 0x08  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_retain             | 0x10  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_copy               | 0x20  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_nonatomic          | 0x40  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_setter             | 0x80  |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_atomic             | 0x100 |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_weak               | 0x200 |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_strong             | 0x400 |
++--------------------------------------+-------+
+| DW_APPLE_PROPERTY_unsafe_unretained  | 0x800 |
++--------------------------------+-----+-------+
 
 Name Accelerator Tables
 -----------------------
 
 Introduction
 ^^^^^^^^^^^^
 
 The "``.debug_pubnames``" and "``.debug_pubtypes``" formats are not what a

include/llvm/Support/Dwarf.h

 enum LocationListEntry : unsigned char {
   DW_LLE_end_of_list_entry,
   DW_LLE_base_address_selection_entry,
   DW_LLE_start_end_entry,
   DW_LLE_start_length_entry,
   DW_LLE_offset_pair_entry
 };
 
+/// Contstants for the DW_APPLE_PROPERTY_attributes attribute.
+/// Keep this list in sync with clang's DeclSpec.h ObjCPropertyAttributeKind.
 enum ApplePropertyAttributes {
   // Apple Objective-C Property Attributes
   DW_APPLE_PROPERTY_readonly = 0x01,
-  DW_APPLE_PROPERTY_readwrite = 0x02,
+  DW_APPLE_PROPERTY_getter = 0x02,
   DW_APPLE_PROPERTY_assign = 0x04,
-  DW_APPLE_PROPERTY_retain = 0x08,
-  DW_APPLE_PROPERTY_copy = 0x10,
-  DW_APPLE_PROPERTY_nonatomic = 0x20
+  DW_APPLE_PROPERTY_readwrite = 0x08,
+  DW_APPLE_PROPERTY_retain = 0x10,
+  DW_APPLE_PROPERTY_copy = 0x20,
+  DW_APPLE_PROPERTY_nonatomic = 0x40,
+  DW_APPLE_PROPERTY_setter = 0x80,
+  DW_APPLE_PROPERTY_atomic = 0x100,
+  DW_APPLE_PROPERTY_weak =   0x200,
+  DW_APPLE_PROPERTY_strong = 0x400,
+  DW_APPLE_PROPERTY_unsafe_unretained = 0x800
 };
 
 /// TagString - Return the string for the specified tag.
 ///
 const char *TagString(unsigned Tag);
 
 /// ChildrenString - Return the string for the specified children flag.
 ///