https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/154119
This breaks a ton of libc++ tests otherwise, since calling std::destroy_at will currently end the lifetime of the entire array not just the given element. See https://github.com/llvm/llvm-project/issues/147528 >From f1ff40ffaa7b73cf9322e34840675ae8bf42508c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com> Date: Mon, 18 Aug 2025 15:54:29 +0200 Subject: [PATCH] [clang][bytecode] Disable EndLifetime op for array elements This breaks a ton of libc++ tests otherwise, since calling std::destroy_at will currently end the lifetime of the entire array not just the given element. See https://github.com/llvm/llvm-project/issues/147528 --- clang/lib/AST/ByteCode/Interp.cpp | 10 ++++++++++ clang/test/AST/ByteCode/builtin-functions.cpp | 10 ++++++---- clang/test/AST/ByteCode/lifetimes26.cpp | 17 +++++++++++++++++ 3 files changed, 33 insertions(+), 4 deletions(-) diff --git a/clang/lib/AST/ByteCode/Interp.cpp b/clang/lib/AST/ByteCode/Interp.cpp index 931d3879f0ff8..aeab9ff381711 100644 --- a/clang/lib/AST/ByteCode/Interp.cpp +++ b/clang/lib/AST/ByteCode/Interp.cpp @@ -1852,6 +1852,11 @@ bool EndLifetime(InterpState &S, CodePtr OpPC) { const auto &Ptr = S.Stk.peek<Pointer>(); if (Ptr.isBlockPointer() && !CheckDummy(S, OpPC, Ptr.block(), AK_Destroy)) return false; + + // FIXME: We need per-element lifetime information for primitive arrays. + if (Ptr.isArrayElement()) + return true; + endLifetimeRecurse(Ptr.narrow()); return true; } @@ -1861,6 +1866,11 @@ bool EndLifetimePop(InterpState &S, CodePtr OpPC) { const auto &Ptr = S.Stk.pop<Pointer>(); if (Ptr.isBlockPointer() && !CheckDummy(S, OpPC, Ptr.block(), AK_Destroy)) return false; + + // FIXME: We need per-element lifetime information for primitive arrays. + if (Ptr.isArrayElement()) + return true; + endLifetimeRecurse(Ptr.narrow()); return true; } diff --git a/clang/test/AST/ByteCode/builtin-functions.cpp b/clang/test/AST/ByteCode/builtin-functions.cpp index 878c0d1a40f26..3277ef65a880b 100644 --- a/clang/test/AST/ByteCode/builtin-functions.cpp +++ b/clang/test/AST/ByteCode/builtin-functions.cpp @@ -1789,9 +1789,11 @@ namespace WithinLifetime { } xstd; // both-error {{is not a constant expression}} \ // both-note {{in call to}} + /// FIXME: We do not have per-element lifetime information for primitive arrays. + /// See https://github.com/llvm/llvm-project/issues/147528 consteval bool test_dynamic(bool read_after_deallocate) { std::allocator<int> a; - int* p = a.allocate(1); + int* p = a.allocate(1); // expected-note 2{{allocation performed here was not deallocated}} // a.allocate starts the lifetime of an array, // the complete object of *p has started its lifetime if (__builtin_is_within_lifetime(p)) @@ -1804,12 +1806,12 @@ namespace WithinLifetime { return false; a.deallocate(p, 1); if (read_after_deallocate) - __builtin_is_within_lifetime(p); // both-note {{read of heap allocated object that has been deleted}} + __builtin_is_within_lifetime(p); // ref-note {{read of heap allocated object that has been deleted}} return true; } - static_assert(test_dynamic(false)); + static_assert(test_dynamic(false)); // expected-error {{not an integral constant expression}} static_assert(test_dynamic(true)); // both-error {{not an integral constant expression}} \ - // both-note {{in call to}} + // ref-note {{in call to}} } #ifdef __SIZEOF_INT128__ diff --git a/clang/test/AST/ByteCode/lifetimes26.cpp b/clang/test/AST/ByteCode/lifetimes26.cpp index a5203ae77bc13..9a1f269b4f55c 100644 --- a/clang/test/AST/ByteCode/lifetimes26.cpp +++ b/clang/test/AST/ByteCode/lifetimes26.cpp @@ -47,3 +47,20 @@ constexpr void destroy_pointer() { } static_assert((destroy_pointer(), true)); + +namespace DestroyArrayElem { + /// This is proof that std::destroy_at'ing an array element + /// ends the lifetime of the entire array. + /// See https://github.com/llvm/llvm-project/issues/147528 + /// Using destroy_at on array elements is currently a no-op due to this. + constexpr int test() { + int a[4] = {}; + + std::destroy_at(&a[3]); + int r = a[1]; + std::construct_at(&a[3]); + + return r; + } + static_assert(test() == 0); +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
