[clang][Interp] Handle CXXConstructExprs

[tbaeder]

Summary

Fixes a so far broken Lambda test case.

[tbaeder]

I think this makes https://reviews.llvm.org/D153653 unnecessary(?)

[tbaeder]

Ping

[tbaeder]

Ping

[shafik]

clang/lib/AST/Interp/ByteCodeExprGen.cpp

1109

Should we be checking isElidable()?

[tbaeder]

Superseeded by https://reviews.llvm.org/D156027.

clang/lib/AST/Interp/ByteCodeExprGen.h

public:
   bool VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E);
   bool VisitCXXTemporaryObjectExpr(const CXXTemporaryObjectExpr *E);
   bool VisitCompoundLiteralExpr(const CompoundLiteralExpr *E);
   bool VisitTypeTraitExpr(const TypeTraitExpr *E);
   bool VisitLambdaExpr(const LambdaExpr *E);
   bool VisitPredefinedExpr(const PredefinedExpr *E);
   bool VisitCXXThrowExpr(const CXXThrowExpr *E);
   bool VisitCXXReinterpretCastExpr(const CXXReinterpretCastExpr *E);
+  bool VisitCXXConstructExpr(const CXXConstructExpr *E);
 
 protected:
   bool visitExpr(const Expr *E) override;
   bool visitDecl(const VarDecl *VD) override;
 
 protected:
   /// Emits scope cleanup instructions.
   void emitCleanup();

clang/lib/AST/Interp/ByteCodeExprGen.cpp

 bool ByteCodeExprGen<Emitter>::VisitCXXReinterpretCastExpr(
     const CXXReinterpretCastExpr *E) {
   if (!this->discard(E->getSubExpr()))
     return false;
 
   return this->emitInvalidCast(CastKind::Reinterpret, E);
 }
 
+template <class Emitter>
+bool ByteCodeExprGen<Emitter>::VisitCXXConstructExpr(
+    const CXXConstructExpr *E) {
+  if (std::optional<unsigned> GI = allocateLocal(E, /*IsExtended=*/false)) {
+    if (!this->emitGetPtrLocal(*GI, E))
+      return false;
+
+    if (!this->visitRecordInitializer(E))
+      return false;
+
+    if (DiscardResult)
+      return this->emitPopPtr(E);
+    return true;
+  }
+
+  return false;
+}
+
 template <class Emitter> bool ByteCodeExprGen<Emitter>::discard(const Expr *E) {
   if (E->containsErrors())
     return false;
 
   OptionScope<Emitter> Scope(this, /*NewDiscardResult=*/true);
   return this->Visit(E);
 }
 

clang/test/AST/Interp/lambda.cpp

namespace StaticInvoker {
 
   constexpr int sv4(int i) {
     auto l = [](int &m) { return m; };
     int (*fp)(int&) = l;
     return fp(i);
   }
   static_assert(sv4(12) == 12);
 
-
-
-  /// FIXME: This is broken for lambda-unrelated reasons.
-#if 0
   constexpr int sv5(int i) {
     struct F { int a; float f; };
     auto l = [](int m, F f) { return m; };
     int (*fp)(int, F) = l;
     return fp(i, F{12, 14.0});
   }
   static_assert(sv5(12) == 12);
-#endif
 
   constexpr int sv6(int i) {
     struct F { int a;
       constexpr F(int a) : a(a) {}
     };
 
     auto l = [](int m) { return F(12); };
     F (*fp)(int) = l;
     F f = fp(i);
 
     return fp(i).a;
   }
   static_assert(sv6(12) == 12);
 }