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

[Raphael Isemann via Phabricator via lldb-commits]

teemperor requested changes to this revision.
teemperor added a comment.
This revision now requires changes to proceed.

A few comments, but otherwise this seems good.



================
Comment at: lldb/include/lldb/Target/Language.h:214
 
+  virtual llvm::StringRef NilReferenceSummaryString() { return {}; }
+
----------------
`/// Returns the summary string that should be used for a ValueObject for which IsNilReference() is true` or something like that.

Also I think this probably should have a `Get` prefix like the other methods in this class.


================
Comment at: lldb/source/DataFormatters/ValueObjectPrinter.cpp:367
+      else
+        summary.assign("0x0");
+    } else if (IsUninitialized())
----------------
JDevlieghere wrote:
> If we had a C runtime we could print "NULL", but I don't think it's worth adding that just for this. Another alternative would be to just have a switch based on the `LanguageType`, but that seems like a pretty bad idea from a layering perspective. 
Not sure what to think about hardcoding `0x0` here. You can specify all kind of formatters that would format the value here differently and this seems kinda inconsistent.
```
(lldb) expr --format d -- nullptr
(nullptr_t) $2 = 0
(lldb) expr --format b -- nullptr
(nullptr_t) $3 = 0b0000000000000000000000000000000000000000000000000000000000000000
```

Could we just fall to the default formatter if we don't have a special summary from the plugin?


================
Comment at: lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp:1138
+bool CPlusPlusLanguage::IsNilReference(ValueObject &valobj) {
+  if (valobj.GetCompilerType().GetMinimumLanguage() !=
+          eLanguageTypeC_plus_plus ||
----------------
Nit: `!Language::LanguageIsCPlusPlus(valobj.GetCompilerType().GetMinimumLanguage())` ? (as we might return a specific C++ standard in the future from GetMinimumLanguage).


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77153/new/

https://reviews.llvm.org/D77153