3 files changed, 22 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index 41fa45f2507..48f8addd031 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -434,6 +434,10 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
       assert(LocationKind != Register);
       emitOp(dwarf::DW_OP_xderef);
       break;
+    case dwarf::DW_OP_deref_size:
+      emitOp(dwarf::DW_OP_deref_size);
+      emitUnsigned(Op->getArg(0));
+      break;
     default:
       llvm_unreachable("unhandled opcode found in expression");
     }
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index 971944be2f9..d414b6a0b4b 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -1854,6 +1854,11 @@ bool MIParser::parseDIExpression(MDNode *&Expr) {
           Elements.push_back(Op);
           continue;
         }
+        if (unsigned Enc = dwarf::getAttributeEncoding(Token.stringValue())) {
+          lex();
+          Elements.push_back(Enc);
+          continue;
+        }
         return error(Twine("invalid DWARF op '") + Token.stringValue() + "'");
       }
 
diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
index 67834c8c352..31f962eba42 100644
--- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp
+++ b/llvm/lib/CodeGen/PrologEpilogInserter.cpp
@@ -1172,12 +1172,22 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &MF,
         assert(i == 0 && "Frame indices can only appear as the first "
                          "operand of a DBG_VALUE machine instruction");
         unsigned Reg;
+        unsigned FrameIdx = MI.getOperand(0).getIndex();
+        unsigned Size = MF.getFrameInfo().getObjectSize(FrameIdx);
+
         int64_t Offset =
-            TFI->getFrameIndexReference(MF, MI.getOperand(0).getIndex(), Reg);
+            TFI->getFrameIndexReference(MF, FrameIdx, Reg);
         MI.getOperand(0).ChangeToRegister(Reg, false /*isDef*/);
         MI.getOperand(0).setIsDebug();
-        auto *DIExpr = DIExpression::prepend(MI.getDebugExpression(),
-                                             DIExpression::NoDeref, Offset);
+
+        const DIExpression *DIExpr = MI.getDebugExpression();
+        // If we already have a Implicit location expression we need to insert
+        // a deref before prepending a Memory location expression.
+        if (DIExpr->isImplicit()) {
+          SmallVector<uint64_t, 2> Ops = {dwarf::DW_OP_deref_size, Size};
+          DIExpr = DIExpression::prependOpcodes(DIExpr, Ops, DIExpression::WithStackValue);
+        }
+        DIExpr = DIExpression::prepend(DIExpr, DIExpression::NoDeref, Offset);
         MI.getOperand(3).setMetadata(DIExpr);
         continue;
       }