Simplify the creation of DIExpressions. (NFC)

Author: adrian-prantl

lib/IRGen/IRGenDebugInfo.cpp

@@ -1002,14 +1002,7 @@ void IRGenDebugInfo::emitVariableDeclaration(
 
   // Create the descriptor for the variable.
   llvm::DILocalVariable *Var = nullptr;
-  llvm::DIExpression *Expr = DBuilder.createExpression();
 
-  if (Indirection) {
-    // Classes are always passed by reference.
-    int64_t Addr[] = { llvm::dwarf::DW_OP_deref };
-    Expr = DBuilder.createExpression(Addr);
-    // FIXME: assert(Flags == 0 && "Complex variables cannot have flags");
-  }
   /// This could be Opts.Optimize if we would also unique DIVariables here.
   bool Optimized = false;
   Var = (ArgNo > 0)
@@ -1027,6 +1020,10 @@ void IRGenDebugInfo::emitVariableDeclaration(
   ElementSizes EltSizes(DITy, DIRefMap, IndirectEnumCases);
   auto Dim = EltSizes.getNext();
   for (llvm::Value *Piece : Storage) {
+    SmallVector<uint64_t, 3> Operands;
+    if (Indirection)
+      Operands.push_back(llvm::dwarf::DW_OP_deref);
+
     // There are variables without storage, such as "struct { func foo() {} }".
     // Emit them as constant 0.
     if (isa<llvm::UndefValue>(Piece))
@@ -1053,27 +1050,25 @@ void IRGenDebugInfo::emitVariableDeclaration(
       assert(Dim.SizeInBits < VarSizeInBits
              && "piece covers entire var");
       assert(OffsetInBits+Dim.SizeInBits <= VarSizeInBits && "pars > totum");
-      SmallVector<uint64_t, 3> Elts;
-      if (Indirection)
-        Elts.push_back(llvm::dwarf::DW_OP_deref);
-      Elts.push_back(llvm::dwarf::DW_OP_bit_piece);
-      Elts.push_back(OffsetInBits);
-      Elts.push_back(Dim.SizeInBits);
-      Expr = DBuilder.createExpression(Elts);
+      Operands.push_back(llvm::dwarf::DW_OP_bit_piece);
+      Operands.push_back(OffsetInBits);
+      Operands.push_back(Dim.SizeInBits);
 
       auto Size = Dim.SizeInBits;
       Dim = EltSizes.getNext();
       OffsetInBits +=
         llvm::RoundUpToAlignment(Size, Dim.AlignInBits ? Dim.AlignInBits
                                                        : SizeOfByte);
     }
-    emitDbgIntrinsic(BB, Piece, Var, Expr, Line, Loc.Col, Scope, DS);
+    emitDbgIntrinsic(BB, Piece, Var, DBuilder.createExpression(Operands), Line,
+                     Loc.Col, Scope, DS);
   }
 
   // Emit locationless intrinsic for variables that were optimized away.
   if (Storage.size() == 0) {
     auto *undef = llvm::UndefValue::get(DbgTy.StorageType);
-    emitDbgIntrinsic(BB, undef, Var, Expr, Line, Loc.Col, Scope, DS);
+    emitDbgIntrinsic(BB, undef, Var, DBuilder.createExpression(), Line, Loc.Col,
+                     Scope, DS);
   }
 }