[LiveDebugValues] Handle spills of indirect debug values correctly

When handling register spill for indirect debug value LiveDebugValues pass doesn't add
DW_OP_deref operator which may in some cases cause debugger to return value address, instead
of value while machine register holding that address is spilled.

Differential revision: https://reviews.llvm.org/D109142

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/LiveDebugValues/VarLocBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/VarLocBasedImpl.cpp
index 2566907..99a57b5 100644
--- a/llvm/lib/CodeGen/LiveDebugValues/VarLocBasedImpl.cpp
+++ b/llvm/lib/CodeGen/LiveDebugValues/VarLocBasedImpl.cpp
@@ -556,9 +556,10 @@ private:
           unsigned Base = Loc.SpillLocation.SpillBase;
           auto *TRI = MF.getSubtarget().getRegisterInfo();
           if (MI.isNonListDebugValue()) {
-            DIExpr =
-                TRI->prependOffsetExpression(DIExpr, DIExpression::ApplyOffset,
-                                             Loc.SpillLocation.SpillOffset);
+            auto Deref = Indirect ? DIExpression::DerefAfter : 0;
+            DIExpr = TRI->prependOffsetExpression(
+                DIExpr, DIExpression::ApplyOffset | Deref,
+                Loc.SpillLocation.SpillOffset);
             Indirect = true;
           } else {
             SmallVector<uint64_t, 4> Ops;