[PATCH] D117779: [LLDB] Add formatters for PointerIntPair, PointerUnion

[Sergej Jaskiewicz via Phabricator via llvm-commits]

broadwaylamb added a comment.

In D117779#3258798 <https://reviews.llvm.org/D117779#3258798>, @kastiglione wrote:

> I take it these expression evaluations are necessary?

Well, I think they are. There is too much template magic behind figuring out how much bits in the pointer we use to store an additional integer value.

Expression evaluations are not only slow, but they also prevent us from formatting nested PointerIntPairs, since the expression path is modified and doesn't correspond to the actual implementation anymore, therefore evaluating expressions down the tree will not work.
But I guess we can live with that for now.



================
Comment at: llvm/utils/lldbDataFormatters.py:175
         max_length = 256
-        length = valobj.GetChildAtIndex(1).GetValueAsUnsigned(max_length)
+        length = min(max_length, valobj.GetChildAtIndex(1).GetValueAsUnsigned(max_length))
         if length == 0:
----------------
kastiglione wrote:
> when the string length is greater than `max_length`, it would be nice for the returned string to indicate truncation. I just checked a long `std::string` and the output was:
> 
> ```
> "really long string"...
> ```
> 
> Also the max length for `std::string` is 1024, should `StringRef` use 1024 too?
LLDB supports the `max-string-summary-length` setting, but unfortunately there is no way to get the value of that setting through Python API.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D117779/new/

https://reviews.llvm.org/D117779