Reapply "[Clang][Sema] placement new initializes typedef array with correct size (#83124)" (#89036)
When in-place new-ing a local variable of an array of trivial type, the
generated code calls 'memset' with the correct size of the array,
earlier it was generating size (squared of the typedef array + size).
The cause: typedef TYPE TArray[8]; TArray x; The type of declarator is
Tarray[8] and in SemaExprCXX.cpp::BuildCXXNew we check if it's of
typedef and of constant size then we get the original type and it works
fine for non-dependent cases.
But in case of template we do TreeTransform.h:TransformCXXNEWExpr and
there we again check the allocated type which is TArray[8] and it stays
that way, so ArraySize=(Tarray[8] type, alloc Tarray[8*type]) so the
squared size allocation.
ArraySize gets calculated earlier in TreeTransform.h so that
if(!ArraySize) condition was failing.
fix: I changed that condition to if(ArraySize).
fixes https://github.com/llvm/llvm-project/issues/41441
---------
Co-authored-by: erichkeane <ekeane@nvidia.com>
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 3db558a..d1f7293 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -557,6 +557,7 @@
- Fix a crash in requires expression with templated base class member function. Fixes (#GH84020).
- Fix a crash caused by defined struct in a type alias template when the structure
has fields with dependent type. Fixes (#GH75221).
+- Fix placement new initializes typedef array with correct size. Fixes (#GH41441).
- Fix the Itanium mangling of lambdas defined in a member of a local class (#GH88906)
- Fixed a crash when trying to evaluate a user-defined ``static_assert`` message whose ``size()``
function returns a large or negative value. Fixes (#GH89407).
diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h
index 9404be5..539a18e 100644
--- a/clang/lib/Sema/TreeTransform.h
+++ b/clang/lib/Sema/TreeTransform.h
@@ -12943,6 +12943,19 @@
ArraySize = NewArraySize.get();
}
+ // Per C++0x [expr.new]p5, the type being constructed may be a
+ // typedef of an array type.
+ QualType AllocType = AllocTypeInfo->getType();
+ if (ArraySize && E->isTypeDependent()) {
+ if (const ConstantArrayType *Array =
+ SemaRef.Context.getAsConstantArrayType(AllocType)) {
+ ArraySize = IntegerLiteral::Create(SemaRef.Context, Array->getSize(),
+ SemaRef.Context.getSizeType(),
+ E->getBeginLoc());
+ AllocType = Array->getElementType();
+ }
+ }
+
// Transform the placement arguments (if any).
bool ArgumentChanged = false;
SmallVector<Expr*, 8> PlacementArgs;
@@ -13004,7 +13017,6 @@
return E;
}
- QualType AllocType = AllocTypeInfo->getType();
if (!ArraySize) {
// If no array size was specified, but the new expression was
// instantiated with an array type (e.g., "new T" where T is
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index a1b340b..21cf72a 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -5097,7 +5097,7 @@
DeclsToCheckForDeferredDiags.push_back(getDeclID(D));
if (!DeclsToCheckForDeferredDiags.empty())
Stream.EmitRecord(DECLS_TO_CHECK_FOR_DEFERRED_DIAGS,
- DeclsToCheckForDeferredDiags);
+ DeclsToCheckForDeferredDiags);
// Write the record containing CUDA-specific declaration references.
RecordData CUDASpecialDeclRefs;
diff --git a/clang/test/SemaCXX/PR41441.cpp b/clang/test/SemaCXX/PR41441.cpp
new file mode 100644
index 0000000..3f60b6e
--- /dev/null
+++ b/clang/test/SemaCXX/PR41441.cpp
@@ -0,0 +1,32 @@
+// RUN: %clang --target=x86_64-pc-linux -S -fno-discard-value-names -emit-llvm -o - %s | FileCheck %s
+
+namespace std {
+ using size_t = decltype(sizeof(int));
+};
+void* operator new[](std::size_t, void*) noexcept;
+
+// CHECK: call void @llvm.memset.p0.i64(ptr align 1 %x, i8 0, i64 8, i1 false)
+// CHECK: call void @llvm.memset.p0.i64(ptr align 16 %x, i8 0, i64 32, i1 false)
+template <typename TYPE>
+void f()
+{
+ typedef TYPE TArray[8];
+
+ TArray x;
+ new(&x) TArray();
+}
+
+template <typename T>
+void f1() {
+ int (*x)[1] = new int[1][1];
+}
+template void f1<char>();
+void f2() {
+ int (*x)[1] = new int[1][1];
+}
+
+int main()
+{
+ f<char>();
+ f<int>();
+}
