llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: None (mahtohappy) <details> <summary>Changes</summary> 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 --- Full diff: https://github.com/llvm/llvm-project/pull/89036.diff 3 Files Affected: - (modified) clang/docs/ReleaseNotes.rst (+2) - (modified) clang/lib/Sema/TreeTransform.h (+13-1) - (added) clang/test/SemaCXX/PR41441.cpp (+23) ``````````diff diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 96ad92b540b47f..636d76f1836759 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -534,6 +534,8 @@ Bug Fixes to C++ Support Fixes (#GH70604), (#GH79754), (#GH84163), (#GH84425), (#GH86054), (#GH86398), and (#GH86399). - Fix a crash when deducing ``auto`` from an invalid dereference (#GH88329). - Fix a crash in requires expression with templated base class member function. Fixes (#GH84020). +- placement new initializes typedef array with correct size + (`#GH41441 <https://github.com/llvm/llvm-project/issues/41441>`_) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Sema/TreeTransform.h b/clang/lib/Sema/TreeTransform.h index eb05783a6219dc..0c7fdb357235e1 100644 --- a/clang/lib/Sema/TreeTransform.h +++ b/clang/lib/Sema/TreeTransform.h @@ -12864,6 +12864,19 @@ TreeTransform<Derived>::TransformCXXNewExpr(CXXNewExpr *E) { 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) { + 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; @@ -12925,7 +12938,6 @@ TreeTransform<Derived>::TransformCXXNewExpr(CXXNewExpr *E) { 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/test/SemaCXX/PR41441.cpp b/clang/test/SemaCXX/PR41441.cpp new file mode 100644 index 00000000000000..d0f2917e52f211 --- /dev/null +++ b/clang/test/SemaCXX/PR41441.cpp @@ -0,0 +1,23 @@ +// 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(); +} + +int main() +{ + f<char>(); + f<int>(); +} `````````` </details> https://github.com/llvm/llvm-project/pull/89036 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits