[clang][bytecode] Check lambda captures before binding decls (#148130)

If the given decls is a lambda capture (but also a BindingDecl), handle
it as a lambda capture instead of a BindingDecl.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -6532,14 +6532,13 @@ bool Compiler<Emitter>::visitDeclRef(const ValueDecl *D, const Expr *E) {
   if (DiscardResult)
     return true;
 
-  if (const auto *ECD = dyn_cast<EnumConstantDecl>(D)) {
+  if (const auto *ECD = dyn_cast<EnumConstantDecl>(D))
     return this->emitConst(ECD->getInitVal(), E);
-  } else if (const auto *BD = dyn_cast<BindingDecl>(D)) {
-    return this->visit(BD->getBinding());
-  } else if (const auto *FuncDecl = dyn_cast<FunctionDecl>(D)) {
+  if (const auto *FuncDecl = dyn_cast<FunctionDecl>(D)) {
     const Function *F = getFunction(FuncDecl);
     return F && this->emitGetFnPtr(F, E);
-  } else if (const auto *TPOD = dyn_cast<TemplateParamObjectDecl>(D)) {
+  }
+  if (const auto *TPOD = dyn_cast<TemplateParamObjectDecl>(D)) {
     if (std::optional<unsigned> Index = P.getOrCreateGlobal(D)) {
       if (!this->emitGetPtrGlobal(*Index, E))
         return false;
@@ -6560,21 +6559,25 @@ bool Compiler<Emitter>::visitDeclRef(const ValueDecl *D, const Expr *E) {
   // value.
   bool IsReference = D->getType()->isReferenceType();
 
-  // Check for local/global variables and parameters.
+  // Local variables.
   if (auto It = Locals.find(D); It != Locals.end()) {
     const unsigned Offset = It->second.Offset;
     if (IsReference)
       return this->emitGetLocal(classifyPrim(E), Offset, E);
     return this->emitGetPtrLocal(Offset, E);
-  } else if (auto GlobalIndex = P.getGlobal(D)) {
+  }
+  // Global variables.
+  if (auto GlobalIndex = P.getGlobal(D)) {
     if (IsReference) {
       if (!Ctx.getLangOpts().CPlusPlus11)
         return this->emitGetGlobal(classifyPrim(E), *GlobalIndex, E);
       return this->emitGetGlobalUnchecked(classifyPrim(E), *GlobalIndex, E);
     }
 
     return this->emitGetPtrGlobal(*GlobalIndex, E);
-  } else if (const auto *PVD = dyn_cast<ParmVarDecl>(D)) {
+  }
+  // Function parameters.
+  if (const auto *PVD = dyn_cast<ParmVarDecl>(D)) {
     if (auto It = this->Params.find(PVD); It != this->Params.end()) {
       if (IsReference || !It->second.IsPtr)
         return this->emitGetParam(classifyPrim(E), It->second.Offset, E);
@@ -6600,20 +6603,25 @@ bool Compiler<Emitter>::visitDeclRef(const ValueDecl *D, const Expr *E) {
     return this->visitDeclRef(D, E);
   };
 
-  // Handle lambda captures.
+  // Lambda captures.
   if (auto It = this->LambdaCaptures.find(D);
       It != this->LambdaCaptures.end()) {
     auto [Offset, IsPtr] = It->second;
 
     if (IsPtr)
       return this->emitGetThisFieldPtr(Offset, E);
     return this->emitGetPtrThisField(Offset, E);
-  } else if (const auto *DRE = dyn_cast<DeclRefExpr>(E);
-             DRE && DRE->refersToEnclosingVariableOrCapture()) {
+  }
+
+  if (const auto *DRE = dyn_cast<DeclRefExpr>(E);
+      DRE && DRE->refersToEnclosingVariableOrCapture()) {
     if (const auto *VD = dyn_cast<VarDecl>(D); VD && VD->isInitCapture())
       return revisit(VD);
   }
 
+  if (const auto *BD = dyn_cast<BindingDecl>(D))
+    return this->visit(BD->getBinding());
+
   // Avoid infinite recursion.
   if (D == InitializingDecl)
     return this->emitDummyPtr(D, E);
@@ -6666,7 +6674,7 @@ bool Compiler<Emitter>::visitDeclRef(const ValueDecl *D, const Expr *E) {
     if (VD->evaluateValue())
       return revisit(VD);
 
-    if (!D->getType()->isReferenceType())
+    if (!IsReference)
       return this->emitDummyPtr(D, E);
 
     return this->emitInvalidDeclRef(cast<DeclRefExpr>(E),

clang/test/SemaCXX/cxx1z-constexpr-lambdas.cpp

@@ -3,6 +3,10 @@
 // RUN: %clang_cc1 -std=c++1z -verify -fsyntax-only -fblocks -fdelayed-template-parsing %s -fcxx-exceptions
 // RUN: %clang_cc1 -std=c++14 -verify -fsyntax-only -fblocks %s -DCPP14_AND_EARLIER -fcxx-exceptions
 
+// RUN: %clang_cc1 -std=c++1z -verify -fsyntax-only -fblocks %s -fcxx-exceptions -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -std=c++20 -verify -fsyntax-only -fblocks %s -fcxx-exceptions -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -std=c++1z -verify -fsyntax-only -fblocks -fdelayed-template-parsing %s -fcxx-exceptions -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -std=c++14 -verify -fsyntax-only -fblocks %s -DCPP14_AND_EARLIER -fcxx-exceptions -fexperimental-new-constant-interpreter
 
 namespace test_lambda_is_literal {
 #ifdef CPP14_AND_EARLIER