1 files changed, 24 insertions, 5 deletions
diff --git a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
index 68d25fe37b433..d8d1a5e8f8411 100644
--- a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
@@ -123,7 +123,10 @@ bool DwarfExpression::addMachineReg(const TargetRegisterInfo &TRI,
   const TargetRegisterClass *RC = TRI.getMinimalPhysRegClass(MachineReg);
   unsigned RegSize = TRI.getRegSizeInBits(*RC);
   // Keep track of the bits in the register we already emitted, so we
-  // can avoid emitting redundant aliasing subregs.
+  // can avoid emitting redundant aliasing subregs. Because this is
+  // just doing a greedy scan of all subregisters, it is possible that
+  // this doesn't find a combination of subregisters that fully cover
+  // the register (even though one may exist).
   SmallBitVector Coverage(RegSize, false);
   for (MCSubRegIterator SR(MachineReg, &TRI); SR.isValid(); ++SR) {
     unsigned Idx = TRI.getSubRegIndex(MachineReg, *SR);
@@ -143,7 +146,7 @@ bool DwarfExpression::addMachineReg(const TargetRegisterInfo &TRI,
     if (CurSubReg.test(Coverage)) {
       // Emit a piece for any gap in the coverage.
       if (Offset > CurPos)
-        DwarfRegs.push_back({-1, Offset - CurPos, nullptr});
+        DwarfRegs.push_back({-1, Offset - CurPos, "no DWARF register encoding"});
       DwarfRegs.push_back(
           {Reg, std::min<unsigned>(Size, MaxSize - Offset), "sub-register"});
       if (Offset >= MaxSize)
@@ -154,8 +157,13 @@ bool DwarfExpression::addMachineReg(const TargetRegisterInfo &TRI,
       CurPos = Offset + Size;
     }
   }
-
-  return CurPos;
+  // Failed to find any DWARF encoding.
+  if (CurPos == 0)
+    return false;
+  // Found a partial or complete DWARF encoding.
+  if (CurPos < RegSize)
+    DwarfRegs.push_back({-1, RegSize - CurPos, "no DWARF register encoding"});
+  return true;
 }
 
 void DwarfExpression::addStackValue() {
@@ -341,11 +349,22 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor,
     case dwarf::DW_OP_plus:
     case dwarf::DW_OP_minus:
     case dwarf::DW_OP_mul:
+    case dwarf::DW_OP_div:
+    case dwarf::DW_OP_mod:
+    case dwarf::DW_OP_or:
+    case dwarf::DW_OP_and:
+    case dwarf::DW_OP_xor:
+    case dwarf::DW_OP_shl:
+    case dwarf::DW_OP_shr:
+    case dwarf::DW_OP_shra:
+    case dwarf::DW_OP_lit0:
+    case dwarf::DW_OP_not:
+    case dwarf::DW_OP_dup:
       emitOp(Op->getOp());
       break;
     case dwarf::DW_OP_deref:
       assert(LocationKind != Register);
-      if (LocationKind != Memory && isMemoryLocation(ExprCursor))
+      if (LocationKind != Memory && ::isMemoryLocation(ExprCursor))
         // Turning this into a memory location description makes the deref
         // implicit.
         LocationKind = Memory;