[clang][bytecode] Add support for creating dummies for expressions (#108394)

And use that to fix VisitObjCBoxedExprs.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -3335,7 +3335,11 @@ bool Compiler<Emitter>::VisitObjCBoxedExpr(const ObjCBoxedExpr *E) {
   if (!E->isExpressibleAsConstantInitializer())
     return this->discard(SubExpr) && this->emitInvalid(E);
 
-  return this->delegate(SubExpr);
+  assert(classifyPrim(E) == PT_Ptr);
+  if (std::optional<unsigned> I = P.getOrCreateDummy(E))
+    return this->emitGetPtrGlobal(*I, E);
+
+  return false;
 }
 
 template <class Emitter>
@@ -4118,7 +4122,7 @@ bool Compiler<Emitter>::VisitBuiltinCallExpr(const CallExpr *E,
       BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString ||
       BuiltinID == Builtin::BI__builtin_ptrauth_sign_constant ||
       BuiltinID == Builtin::BI__builtin_function_start) {
-    if (std::optional<unsigned> GlobalOffset = P.createGlobal(E)) {
+    if (std::optional<unsigned> GlobalOffset = P.getOrCreateDummy(E)) {
       if (!this->emitGetPtrGlobal(*GlobalOffset, E))
         return false;
 

clang/lib/AST/ByteCode/Program.cpp

@@ -144,22 +144,33 @@ std::optional<unsigned> Program::getOrCreateGlobal(const ValueDecl *VD,
   return std::nullopt;
 }
 
-std::optional<unsigned> Program::getOrCreateDummy(const ValueDecl *VD) {
+std::optional<unsigned> Program::getOrCreateDummy(const DeclTy &D) {
+  assert(D);
   // Dedup blocks since they are immutable and pointers cannot be compared.
-  if (auto It = DummyVariables.find(VD); It != DummyVariables.end())
+  if (auto It = DummyVariables.find(D.getOpaqueValue());
+      It != DummyVariables.end())
     return It->second;
 
-  QualType QT = VD->getType();
-  if (const auto *RT = QT->getAs<ReferenceType>())
-    QT = RT->getPointeeType();
+  QualType QT;
+  if (const auto *E = D.dyn_cast<const Expr *>()) {
+    QT = E->getType();
+  } else {
+    const ValueDecl *VD = cast<ValueDecl>(D.get<const Decl *>());
+    QT = VD->getType();
+    if (const auto *RT = QT->getAs<ReferenceType>())
+      QT = RT->getPointeeType();
+  }
+  assert(!QT.isNull());
 
   Descriptor *Desc;
   if (std::optional<PrimType> T = Ctx.classify(QT))
-    Desc = createDescriptor(VD, *T, std::nullopt, true, false);
+    Desc = createDescriptor(D, *T, std::nullopt, /*IsTemporary=*/true,
+                            /*IsMutable=*/false);
   else
-    Desc = createDescriptor(VD, QT.getTypePtr(), std::nullopt, true, false);
+    Desc = createDescriptor(D, QT.getTypePtr(), std::nullopt,
+                            /*IsTemporary=*/true, /*IsMutable=*/false);
   if (!Desc)
-    Desc = allocateDescriptor(VD);
+    Desc = allocateDescriptor(D);
 
   assert(Desc);
   Desc->makeDummy();
@@ -175,7 +186,7 @@ std::optional<unsigned> Program::getOrCreateDummy(const ValueDecl *VD) {
   G->block()->invokeCtor();
 
   Globals.push_back(G);
-  DummyVariables[VD] = I;
+  DummyVariables[D.getOpaqueValue()] = I;
   return I;
 }
 

clang/lib/AST/ByteCode/Program.h

@@ -84,7 +84,7 @@ class Program final {
                                             const Expr *Init = nullptr);
 
   /// Returns or creates a dummy value for unknown declarations.
-  std::optional<unsigned> getOrCreateDummy(const ValueDecl *VD);
+  std::optional<unsigned> getOrCreateDummy(const DeclTy &D);
 
   /// Creates a global and returns its index.
   std::optional<unsigned> createGlobal(const ValueDecl *VD, const Expr *Init);
@@ -209,7 +209,7 @@ class Program final {
   llvm::DenseMap<const RecordDecl *, Record *> Records;
 
   /// Dummy parameter to generate pointers from.
-  llvm::DenseMap<const ValueDecl *, unsigned> DummyVariables;
+  llvm::DenseMap<const void *, unsigned> DummyVariables;
 
   /// Creates a new descriptor.
   template <typename... Ts> Descriptor *allocateDescriptor(Ts &&...Args) {

clang/test/CodeGenObjC/boxing.m

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -o - %s -fexperimental-new-constant-interpreter | FileCheck %s
 
 typedef long NSInteger;
 typedef unsigned long NSUInteger;