[PATCH] D125509: [LLDB][NFC] Decouple dwarf location table from DWARFExpression.

[Zequan Wu via Phabricator via llvm-commits]

zequanwu added inline comments.


================
Comment at: lldb/source/Expression/DWARFExpressionList.cpp:179
+  if (m_exprs.GetSize() == 1) {
+    expr = m_exprs.Back()->data;
+  } else {
----------------
labath wrote:
> I don't think this is correct.
> 
> We should be able to distinguish between a location list that is always valid (i.e., one which is not a location list at all), and a location list which happens to contain a single valid range.
> 
> That could probably be achieved by making the range of the always-valid entry be (0, UINT_MAX), but maybe it would be better to have an explicit fallback/default entry for this (one that is used when no ranged entry applies). This is how the default location entries in DWARF5 are supposed to work, although I am not sure if any compiler actually makes use of them.
> That could probably be achieved by making the range of the always-valid entry be (0, UINT_MAX)
This looks better to me as it saves one default entry and there is no difference in terms of using DWARFExpressionList APIs. 
Added `IsAlwaysValidSingleExpr` to check if it is an always-valid entry and uses it to distinguish between the two kinds.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D125509/new/

https://reviews.llvm.org/D125509