[clang][bytecode] Fix __builtin_memmove type diagnostics (#132544)

tbaederr · web-flow · commit c51d396f4dec · 2025-03-22T14:58:32.000+01:00
Set the source type when allocating primitives so we can later retrieve
it.
diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp
@@ -3356,7 +3356,8 @@ bool Compiler<Emitter>::VisitCXXNewExpr(const CXXNewExpr *E) {
       if (E->isArray())
         Desc = nullptr; // We're not going to use it in this case.
       else
-        Desc = P.createDescriptor(E, *ElemT, Descriptor::InlineDescMD,
+        Desc = P.createDescriptor(E, *ElemT, /*SourceTy=*/nullptr,
+                                  Descriptor::InlineDescMD,
                                   /*IsConst=*/false, /*IsTemporary=*/false,
                                   /*IsMutable=*/false);
     } else {
@@ -4260,8 +4261,8 @@ unsigned Compiler<Emitter>::allocateLocalPrimitive(
   // FIXME: There are cases where Src.is<Expr*>() is wrong, e.g.
   //   (int){12} in C. Consider using Expr::isTemporaryObject() instead
   //   or isa<MaterializeTemporaryExpr>().
-  Descriptor *D = P.createDescriptor(Src, Ty, Descriptor::InlineDescMD, IsConst,
-                                     isa<const Expr *>(Src));
+  Descriptor *D = P.createDescriptor(Src, Ty, nullptr, Descriptor::InlineDescMD,
+                                     IsConst, isa<const Expr *>(Src));
   Scope::Local Local = this->createLocal(D);
   if (auto *VD = dyn_cast_if_present<ValueDecl>(Src.dyn_cast<const Decl *>()))
     Locals.insert({VD, Local});
diff --git a/clang/lib/AST/ByteCode/Descriptor.cpp b/clang/lib/AST/ByteCode/Descriptor.cpp
@@ -329,9 +329,10 @@ static BlockMoveFn getMoveArrayPrim(PrimType Type) {
 }
 
 /// Primitives.
-Descriptor::Descriptor(const DeclTy &D, PrimType Type, MetadataSize MD,
-                       bool IsConst, bool IsTemporary, bool IsMutable)
-    : Source(D), ElemSize(primSize(Type)), Size(ElemSize),
+Descriptor::Descriptor(const DeclTy &D, const Type *SourceTy, PrimType Type,
+                       MetadataSize MD, bool IsConst, bool IsTemporary,
+                       bool IsMutable)
+    : Source(D), SourceType(SourceTy), ElemSize(primSize(Type)), Size(ElemSize),
       MDSize(MD.value_or(0)), AllocSize(align(Size + MDSize)), PrimT(Type),
       IsConst(IsConst), IsMutable(IsMutable), IsTemporary(IsTemporary),
       CtorFn(getCtorPrim(Type)), DtorFn(getDtorPrim(Type)),
diff --git a/clang/lib/AST/ByteCode/Descriptor.h b/clang/lib/AST/ByteCode/Descriptor.h
@@ -175,8 +175,8 @@ struct Descriptor final {
   const BlockMoveFn MoveFn = nullptr;
 
   /// Allocates a descriptor for a primitive.
-  Descriptor(const DeclTy &D, PrimType Type, MetadataSize MD, bool IsConst,
-             bool IsTemporary, bool IsMutable);
+  Descriptor(const DeclTy &D, const Type *SourceTy, PrimType Type,
+             MetadataSize MD, bool IsConst, bool IsTemporary, bool IsMutable);
 
   /// Allocates a descriptor for an array of primitives.
   Descriptor(const DeclTy &D, PrimType Type, MetadataSize MD, size_t NumElems,
diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp
@@ -149,6 +149,18 @@ static bool retPrimValue(InterpState &S, CodePtr OpPC,
 #undef RET_CASE
 }
 
+static QualType getElemType(const Pointer &P) {
+  const Descriptor *Desc = P.getFieldDesc();
+  QualType T = Desc->getType();
+  if (Desc->isPrimitive())
+    return T;
+  if (T->isPointerType())
+    return T->getAs<PointerType>()->getPointeeType();
+  if (Desc->isArray())
+    return Desc->getElemQualType();
+  return T;
+}
+
 static void diagnoseNonConstexprBuiltin(InterpState &S, CodePtr OpPC,
                                         unsigned ID) {
   auto Loc = S.Current->getSource(OpPC);
@@ -1575,10 +1587,10 @@ static bool interp__builtin_operator_new(InterpState &S, CodePtr OpPC,
       return true;
     }
 
-    const Descriptor *Desc =
-        S.P.createDescriptor(NewCall, *ElemT, Descriptor::InlineDescMD,
-                             /*IsConst=*/false, /*IsTemporary=*/false,
-                             /*IsMutable=*/false);
+    const Descriptor *Desc = S.P.createDescriptor(
+        NewCall, *ElemT, ElemType.getTypePtr(), Descriptor::InlineDescMD,
+        /*IsConst=*/false, /*IsTemporary=*/false,
+        /*IsMutable=*/false);
     Block *B = Allocator.allocate(Desc, S.getContext().getEvalID(),
                                   DynamicAllocator::Form::Operator);
     assert(B);
@@ -1782,15 +1794,13 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
   if (DestPtr.isDummy() || SrcPtr.isDummy())
     return false;
 
-  QualType DestElemType;
+  QualType DestElemType = getElemType(DestPtr);
   size_t RemainingDestElems;
   if (DestPtr.getFieldDesc()->isArray()) {
-    DestElemType = DestPtr.getFieldDesc()->getElemQualType();
     RemainingDestElems = DestPtr.isUnknownSizeArray()
                              ? 0
                              : (DestPtr.getNumElems() - DestPtr.getIndex());
   } else {
-    DestElemType = DestPtr.getType();
     RemainingDestElems = 1;
   }
   unsigned DestElemSize = ASTCtx.getTypeSizeInChars(DestElemType).getQuantity();
@@ -1803,15 +1813,13 @@ static bool interp__builtin_memcpy(InterpState &S, CodePtr OpPC,
     return false;
   }
 
-  QualType SrcElemType;
+  QualType SrcElemType = getElemType(SrcPtr);
   size_t RemainingSrcElems;
   if (SrcPtr.getFieldDesc()->isArray()) {
-    SrcElemType = SrcPtr.getFieldDesc()->getElemQualType();
     RemainingSrcElems = SrcPtr.isUnknownSizeArray()
                             ? 0
                             : (SrcPtr.getNumElems() - SrcPtr.getIndex());
   } else {
-    SrcElemType = SrcPtr.getType();
     RemainingSrcElems = 1;
   }
   unsigned SrcElemSize = ASTCtx.getTypeSizeInChars(SrcElemType).getQuantity();
@@ -1884,16 +1892,6 @@ static bool interp__builtin_memcmp(InterpState &S, CodePtr OpPC,
   bool IsWide =
       (ID == Builtin::BIwmemcmp || ID == Builtin::BI__builtin_wmemcmp);
 
-  auto getElemType = [](const Pointer &P) -> QualType {
-    const Descriptor *Desc = P.getFieldDesc();
-    QualType T = Desc->getType();
-    if (T->isPointerType())
-      return T->getAs<PointerType>()->getPointeeType();
-    if (Desc->isArray())
-      return Desc->getElemQualType();
-    return T;
-  };
-
   const ASTContext &ASTCtx = S.getASTContext();
   QualType ElemTypeA = getElemType(PtrA);
   QualType ElemTypeB = getElemType(PtrB);
diff --git a/clang/lib/AST/ByteCode/Program.cpp b/clang/lib/AST/ByteCode/Program.cpp
@@ -166,7 +166,7 @@ unsigned Program::getOrCreateDummy(const DeclTy &D) {
 
   Descriptor *Desc;
   if (std::optional<PrimType> T = Ctx.classify(QT))
-    Desc = createDescriptor(D, *T, std::nullopt, /*IsTemporary=*/true,
+    Desc = createDescriptor(D, *T, nullptr, std::nullopt, /*IsTemporary=*/true,
                             /*IsMutable=*/false);
   else
     Desc = createDescriptor(D, QT.getTypePtr(), std::nullopt,
@@ -244,7 +244,8 @@ std::optional<unsigned> Program::createGlobal(const DeclTy &D, QualType Ty,
   const bool IsConst = Ty.isConstQualified();
   const bool IsTemporary = D.dyn_cast<const Expr *>();
   if (std::optional<PrimType> T = Ctx.classify(Ty))
-    Desc = createDescriptor(D, *T, Descriptor::GlobalMD, IsConst, IsTemporary);
+    Desc = createDescriptor(D, *T, nullptr, Descriptor::GlobalMD, IsConst,
+                            IsTemporary);
   else
     Desc = createDescriptor(D, Ty.getTypePtr(), Descriptor::GlobalMD, IsConst,
                             IsTemporary);
@@ -365,7 +366,7 @@ Record *Program::getOrCreateRecord(const RecordDecl *RD) {
     const bool IsMutable = FD->isMutable();
     const Descriptor *Desc;
     if (std::optional<PrimType> T = Ctx.classify(FT)) {
-      Desc = createDescriptor(FD, *T, std::nullopt, IsConst,
+      Desc = createDescriptor(FD, *T, nullptr, std::nullopt, IsConst,
                               /*isTemporary=*/false, IsMutable);
     } else {
       Desc = createDescriptor(FD, FT.getTypePtr(), std::nullopt, IsConst,
diff --git a/clang/lib/AST/ByteCode/Program.h b/clang/lib/AST/ByteCode/Program.h
@@ -115,11 +115,13 @@ class Program final {
   Record *getOrCreateRecord(const RecordDecl *RD);
 
   /// Creates a descriptor for a primitive type.
-  Descriptor *createDescriptor(const DeclTy &D, PrimType Type,
+  Descriptor *createDescriptor(const DeclTy &D, PrimType T,
+                               const Type *SourceTy = nullptr,
                                Descriptor::MetadataSize MDSize = std::nullopt,
                                bool IsConst = false, bool IsTemporary = false,
                                bool IsMutable = false) {
-    return allocateDescriptor(D, Type, MDSize, IsConst, IsTemporary, IsMutable);
+    return allocateDescriptor(D, SourceTy, T, MDSize, IsConst, IsTemporary,
+                              IsMutable);
   }
 
   /// Creates a descriptor for a composite type.
diff --git a/clang/test/AST/ByteCode/placement-new.cpp b/clang/test/AST/ByteCode/placement-new.cpp
@@ -376,3 +376,18 @@ constexpr int N = [] // expected-error {{must be initialized by a constant expre
     return s.a[0];
 }();
 #endif
+
+namespace MemMove {
+  constexpr int foo() {
+    int *a = std::allocator<int>{}.allocate(1);
+    new(a) int{123};
+
+    int b;
+    __builtin_memmove(&b, a, sizeof(int));
+
+    std::allocator<int>{}.deallocate(a);
+    return b;
+  }
+
+  static_assert(foo() == 123);
+}
