Add option eTypeOptionHideEmptyAggregates.

Summary:
For certain data structures, when the synthetic child provider returns
zero children, a summary like "Empty instance of <typename>" could be
more appropriate than something like "size=0 {}". This new option helps
hide the trailing "{}".

This is also exposed with a -h option for the command "type summary add".

Reviewers: granata.enrico

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D11473

llvm-svn: 243166

1 files changed, 12 insertions, 1 deletions

diff --git a/lldb/source/DataFormatters/ValueObjectPrinter.cpp b/lldb/source/DataFormatters/ValueObjectPrinter.cpp
index 7c794ee2dda..7fca7a3f0af 100644
--- a/lldb/source/DataFormatters/ValueObjectPrinter.cpp
+++ b/lldb/source/DataFormatters/ValueObjectPrinter.cpp
@@ -480,6 +480,17 @@ ValueObjectPrinter::ShouldPrintChildren (bool is_failed_description,
     return false;
 }
 
+bool
+ValueObjectPrinter::ShouldExpandEmptyAggregates ()
+{
+    TypeSummaryImpl* entry = GetSummaryFormatter();
+
+    if (!entry)
+        return true;
+
+    return entry->DoesPrintEmptyAggregates();
+}
+
 ValueObject*
 ValueObjectPrinter::GetValueObjectForChildrenGeneration ()
 {
@@ -582,7 +593,7 @@ ValueObjectPrinter::PrintChildren (uint32_t curr_ptr_depth)
         if (ShouldPrintValueObject())
         {
             // if it has a synthetic value, then don't print {}, the synthetic children are probably only being used to vend a value
-            if (m_valobj->DoesProvideSyntheticValue())
+            if (m_valobj->DoesProvideSyntheticValue() || !ShouldExpandEmptyAggregates())
                 m_stream->PutCString( "\n");
             else
                 m_stream->PutCString(" {}\n");