[lldb] Add comment on cross printing of summary/value

[kastiglione]

Adds a comment to indicate intention of a piece of value printing code.

I was initially surprised to see this code (distilled for emphasis):

if (str.empty()) {
  if (style == eValueObjectRepresentationStyleValue)
    str = GetSummaryAsCString();
  else if (style == eValueObjectRepresentationStyleSummary)
    str = GetValueAsCString();
}

My first thought was "is this a bug?", but I realized it was likely intentional. This change adds a comment to indicate yes, this is intentional.

[llvmbot]

@llvm/pr-subscribers-lldb

Author: Dave Lee (kastiglione)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/81681.diff

1 Files Affected:

• (modified) lldb/source/Core/ValueObject.cpp (+1)

diff --git a/lldb/source/Core/ValueObject.cpp b/lldb/source/Core/ValueObject.cpp
index e80042826f7d64..2a2bb128d33c57 100644
--- a/lldb/source/Core/ValueObject.cpp
+++ b/lldb/source/Core/ValueObject.cpp
@@ -1312,6 +1312,7 @@ bool ValueObject::DumpPrintableRepresentation(
       break;
     }
 
+    // Try summary if no value, and value if no summary.
     if (str.empty()) {
       if (val_obj_display == eValueObjectRepresentationStyleValue)
         str = GetSummaryAsCString();

[jimingham]

That did deserve a comment. To be pedantic, in the second branch you try value/location if no summary, but what you have is fine.

[kastiglione]

I'll fine tune the wording to match the code.