[DataFormatters] Implement summary for __NSDictionary0.

Before the patch:

(lldb) frame var emptyDictionary
(__NSDictionary0 *) emptyDictionary = 0x0000000100304420

After:

(lldb) frame var emptyDictionary
(__NSDictionary0 *) emptyDictionary = 0x0000000100304420 0 key/value pairs

There's nothing much else we can do, as this is always empty by
definition.

<rdar://problem/34806516>

llvm-svn: 327587

5 files changed, 24 insertions, 0 deletions

diff --git a/lldb/lit/DataFormatters/Inputs/NSDict.commands b/lldb/lit/DataFormatters/Inputs/NSDict.commands
new file mode 100644
index 00000000000..2f03dae3d3e
--- /dev/null
+++ b/lldb/lit/DataFormatters/Inputs/NSDict.commands
@@ -0,0 +1,3 @@
+breakpoint set --file NSDict.m --line 8
+run
+frame var
diff --git a/lldb/lit/DataFormatters/Inputs/NSDict.m b/lldb/lit/DataFormatters/Inputs/NSDict.m
new file mode 100644
index 00000000000..efc96fdc58d
--- /dev/null
+++ b/lldb/lit/DataFormatters/Inputs/NSDict.m
@@ -0,0 +1,9 @@
+#include <Foundation/Foundation.h>
+
+int main(void)
+{
+  NSDictionary *emptyDictionary = [[NSDictionary alloc] init];
+  NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionary];
+  NSDictionary *dictionary = @{ @"key": @{} };
+  return 0;
+}
diff --git a/lldb/lit/DataFormatters/TestEmptyDictionary.test b/lldb/lit/DataFormatters/TestEmptyDictionary.test
new file mode 100644
index 00000000000..c9e6a0c1692
--- /dev/null
+++ b/lldb/lit/DataFormatters/TestEmptyDictionary.test
@@ -0,0 +1,7 @@
+# Test that foundation NSDictionary0 is formatted correctly (the summary).
+# Foundation is only available on Darwin so just restrict the test to run there.
+# REQUIRES: darwin
+# RUN: %cc %p/Inputs/NSDict.m -framework Foundation -g -o %t && %lldb -b \
+# RUN:  -s %p/Inputs/NSDict.commands -- %t 2>&1 | FileCheck %s
+
+# CHECK: (__NSDictionary0 *) emptyDictionary = {{.*}} 0 key/value pairs
diff --git a/lldb/lit/DataFormatters/lit.local.cfg b/lldb/lit/DataFormatters/lit.local.cfg
new file mode 100644
index 00000000000..df9b335dd13
--- /dev/null
+++ b/lldb/lit/DataFormatters/lit.local.cfg
@@ -0,0 +1 @@
+config.suffixes = ['.test']
diff --git a/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp b/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
index 0af36f435ec..67b0ce863a7 100644
--- a/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
+++ b/lldb/source/Plugins/Language/ObjC/NSDictionary.cpp
@@ -396,6 +396,7 @@ bool lldb_private::formatters::NSDictionarySummaryProvider(
   static const ConstString g_DictionaryMLegacy("__NSDictionaryM_Legacy");
   static const ConstString g_DictionaryMImmutable("__NSDictionaryM_Immutable");
   static const ConstString g_Dictionary1("__NSSingleEntryDictionaryI");
+  static const ConstString g_Dictionary0("__NSDictionary0");
 
   if (class_name.IsEmpty())
     return false;
@@ -423,6 +424,8 @@ bool lldb_private::formatters::NSDictionarySummaryProvider(
       return false;
   } else if (class_name == g_Dictionary1) {
     value = 1;
+  } else if (class_name == g_Dictionary0) {
+    value = 0;
   }
   else {
     auto &map(NSDictionary_Additionals::GetAdditionalSummaries());
@@ -481,6 +484,7 @@ lldb_private::formatters::NSDictionarySyntheticFrontEndCreator(
   static const ConstString g_Dictionary1("__NSSingleEntryDictionaryI");
   static const ConstString g_DictionaryImmutable("__NSDictionaryM_Immutable");
   static const ConstString g_DictionaryMLegacy("__NSDictionaryM_Legacy");
+  static const ConstString g_Dictionary0("__NSDictionary0");
 
   if (class_name.IsEmpty())
     return nullptr;