[clang][bytecode] Remove split frame business (llvm#155980)

This was never really needed.

Author: tbaederr

clang/lib/AST/ByteCode/InterpFrame.cpp

@@ -195,12 +195,6 @@ void InterpFrame::describe(llvm::raw_ostream &OS) const {
   OS << ")";
 }
 
-Frame *InterpFrame::getCaller() const {
-  if (Caller->Caller)
-    return Caller;
-  return S.getSplitFrame();
-}
-
 SourceRange InterpFrame::getCallRange() const {
   if (!Caller->Func) {
     if (SourceRange NullRange = S.getRange(nullptr, {}); NullRange.isValid())

clang/lib/AST/ByteCode/InterpFrame.h

@@ -59,7 +59,7 @@ class InterpFrame final : public Frame {
   void describe(llvm::raw_ostream &OS) const override;
 
   /// Returns the parent frame object.
-  Frame *getCaller() const override;
+  Frame *getCaller() const override { return Caller; }
 
   /// Returns the location of the call to the frame.
   SourceRange getCallRange() const override;

clang/lib/AST/ByteCode/InterpState.cpp

@@ -62,11 +62,7 @@ void InterpState::cleanup() {
   Alloc.cleanup();
 }
 
-Frame *InterpState::getCurrentFrame() {
-  if (Current && Current->Caller)
-    return Current;
-  return Parent.getCurrentFrame();
-}
+Frame *InterpState::getCurrentFrame() { return Current; }
 
 bool InterpState::reportOverflow(const Expr *E, const llvm::APSInt &Value) {
   QualType Type = E->getType();

clang/lib/AST/ByteCode/InterpState.h

@@ -57,14 +57,11 @@ class InterpState final : public State, public SourceMapper {
   bool diagnosing() const { return getEvalStatus().Diag != nullptr; }
 
   // Stack frame accessors.
-  Frame *getSplitFrame() { return Parent.getCurrentFrame(); }
   Frame *getCurrentFrame() override;
   unsigned getCallStackDepth() override {
     return Current ? (Current->getDepth() + 1) : 1;
   }
-  const Frame *getBottomFrame() const override {
-    return Parent.getBottomFrame();
-  }
+  const Frame *getBottomFrame() const override { return &BottomFrame; }
 
   // Access objects from the walker context.
   Expr::EvalStatus &getEvalStatus() const override {