DebugInfo: Gut DIExpression

Completely gut `DIExpression`, turning it into a simple wrapper around
`MDExpression *`.  There are two bits of magic left:

  - It's constructed from `const MDExpression*` but convertible to
    `MDExpression*`.
  - It's default-constructed to `nullptr`.

Otherwise, it should behave quite like a raw pointer.  Once I've done
the same to the rest of the `DIDescriptor` subclasses, I'll come back to
delete them entirely (and update call sites as necessary to deal with
the missing magic).

llvm-svn: 234832

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h b/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h
index f50ebae7ba6..dd7f806e029 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DebugLocEntry.h
@@ -76,7 +76,7 @@ public:
     MachineLocation getLoc() const { return Loc; }
     const MDNode *getVariableNode() const { return Variable; }
     DIVariable getVariable() const { return cast<MDLocalVariable>(Variable); }
-    bool isBitPiece() const { return getExpression().isBitPiece(); }
+    bool isBitPiece() const { return getExpression()->isBitPiece(); }
     DIExpression getExpression() const {
       return cast_or_null<MDExpression>(Expression);
     }
@@ -108,8 +108,7 @@ public:
       DIExpression NextExpr =
           cast_or_null<MDExpression>(Next.Values[0].Expression);
       DIVariable NextVar = cast_or_null<MDLocalVariable>(Next.Values[0].Variable);
-      if (Var == NextVar && Expr.isBitPiece() &&
-          NextExpr.isBitPiece()) {
+      if (Var == NextVar && Expr->isBitPiece() && NextExpr->isBitPiece()) {
         addValues(Next.Values);
         End = Next.End;
         return true;
@@ -192,8 +191,8 @@ inline bool operator==(const DebugLocEntry::Value &A,
 /// \brief Compare two pieces based on their offset.
 inline bool operator<(const DebugLocEntry::Value &A,
                       const DebugLocEntry::Value &B) {
-  return A.getExpression().getBitPieceOffset() <
-         B.getExpression().getBitPieceOffset();
+  return A.getExpression()->getBitPieceOffset() <
+         B.getExpression()->getBitPieceOffset();
 }
 
 }