[lldb-dev] problems with dynamic values

Ryan Brown ribrdb at google.com
Tue Mar 24 15:05:23 PDT 2015

I'm trying to support printing go interfaces.
After reading through the list archives, it seems like the way to do this
is add my Go type information to ClangASTType and implement a
So I added a "int m_go_kind" field to ClangASTType and set it in
SymbolFileDWARF. However I'm having a couple issues:

1) It seems like some places create new ClangASTTypes directly instead of
using the ones from the DWARF info. So if I use 'frame variable' I see the
dynamic type, but if I do 'print g' the go type info gets lost.

2) The dynamic values always seem to print as invalid, even though it seems
like I'm returning the right thing from GetDynamicTypeAndAddress. For
(lldb) frame variable
(main.square) g = (width = <parent has invalid value.>, height = <parent
has invalid value.>)

But if I step through the code after GetDynamicTypeAndAddress returns, it
looks like it's successfully reading the data. I can print the actual value
from python:

>>> g = lldb.frame.EvaluateExpression("g")
>>> print g
(main.geometry) $1 = {
  tab = 0x00007ffff7fcf6f0
  data = 0x000000c20800a210
>>> d = g.GetChildAtIndex(1)
>>> print d.Cast(t.GetPointerType()).Dereference()
(main.square) *data = (width = 3, height = 4)

And these addresses are the same ones my C++ code is returning, so I don't
know what's wrong.
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