[Lldb-commits] [PATCH] D77153: [lldb/DataFormatters] Display null C++ pointers as nullptr

[Frederic Riss via Phabricator via lldb-commits]

friss created this revision.
friss added reviewers: jingham, labath.
Herald added a project: LLDB.
friss added a comment.

I haven't tested the libstdc++ part, would be great if someone could confirm this works.


The original motivation for this patch was to display a null
std::string pointer as nullptr instead of "", but the fix
seemed generic enough to be done for all C++ summary providers.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D77153

Files:
  lldb/source/DataFormatters/TypeSummary.cpp
  lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
  lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
  lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/TestDataFormatterStdString.py
  lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/main.cpp


Index: lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/main.cpp
===================================================================
--- lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/main.cpp
+++ lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/main.cpp
@@ -10,6 +10,7 @@
     std::string q("hello world");
     std::string Q("quite a long std::strin with lots of info inside it");
     std::basic_string<unsigned char> uchar(5, 'a');
+    std::string *null = nullptr;
     S.assign(L"!!!!!"); // Set break point at this line.
     return 0;
 }
Index: lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/TestDataFormatterStdString.py
===================================================================
--- lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/TestDataFormatterStdString.py
+++ lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/string/TestDataFormatterStdString.py
@@ -59,6 +59,7 @@
         var_q = self.frame().FindVariable('q')
         var_Q = self.frame().FindVariable('Q')
         var_uchar = self.frame().FindVariable('uchar')
+        var_null = self.frame().FindVariable('null')
 
         self.assertEqual(var_wempty.GetSummary(), 'L""', "wempty summary wrong")
         self.assertEqual(
@@ -76,6 +77,7 @@
             var_Q.GetSummary(), '"quite a long std::strin with lots of info inside it"',
             "Q summary wrong")
         self.assertEqual(var_uchar.GetSummary(), '"aaaaa"', "u summary wrong")
+        self.assertEqual(var_null.GetSummary(), 'nullptr', "null summary wrong")
 
         self.runCmd("next")
 
Index: lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
===================================================================
--- lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
+++ lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/main.cpp
@@ -71,6 +71,7 @@
     std::u32string u32_string(U"🍄🍅🍆🍌");
     std::u32string u32_empty(U"");
     std::basic_string<unsigned char> uchar(5, 'a');
+    std::string *null = nullptr;
 
 #if _LIBCPP_ABI_VERSION == 1
     std::string garbage1, garbage2, garbage3, garbage4, garbage5;
Index: lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
===================================================================
--- lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
+++ lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/string/TestDataFormatterLibcxxString.py
@@ -77,6 +77,7 @@
                 '(%s::u32string) u32_empty = ""'%ns,
                 '(%s::basic_string<unsigned char, %s::char_traits<unsigned char>, '
                 '%s::allocator<unsigned char> >) uchar = "aaaaa"'%(ns,ns,ns),
+                '(std::string *) null = nullptr',
         ])
 
         self.runCmd("n")
@@ -114,6 +115,7 @@
                 '(%s::u32string) u32_empty = ""'%ns,
                 '(%s::basic_string<unsigned char, %s::char_traits<unsigned char>, '
                 '%s::allocator<unsigned char> >) uchar = "aaaaa"'%(ns,ns,ns),
+                '(std::string *) null = nullptr',
         ])
 
         # The test assumes that std::string is in its cap-size-data layout.
Index: lldb/source/DataFormatters/TypeSummary.cpp
===================================================================
--- lldb/source/DataFormatters/TypeSummary.cpp
+++ lldb/source/DataFormatters/TypeSummary.cpp
@@ -123,6 +123,17 @@
                                             std::string &dest,
                                             const TypeSummaryOptions &options) {
   dest.clear();
+
+  if (valobj && valobj->IsPointerType()) {
+    bool success = true;
+    if (!valobj->GetValueAsUnsigned(0, &success)) {
+      if (!success)
+        return false;
+      dest = "nullptr";
+      return true;
+    }
+  }
+
   StreamString stream;
   if (!m_impl || !m_impl(*valobj, stream, options))
     return false;


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