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[Clang] Fix missing diagnostic for non-standard layout type in offsetof #65246

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Merged
merged 1 commit into from
Oct 10, 2023
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[Clang] Fix missing diagnostic for non-standard layout type in offsetof #65246

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2 changes: 2 additions & 0 deletions clang/docs/ReleaseNotes.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -270,6 +270,8 @@ Improvements to Clang's diagnostics
source:1:24: note: expression evaluates to ''\n' (0x0A, 10) == U'🌍' (0x1F30D, 127757)'
1 | static_assert("A\n"[1] == U'🌍');
| ~~~~~~~~~^~~~~~~~
- Clang now always diagnoses when using non-standard layout types in ``offsetof`` .
(`#64619: <https://github.com/llvm/llvm-project/issues/64619>`_)

Bug Fixes in This Version
-------------------------
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9 changes: 4 additions & 5 deletions clang/lib/Sema/SemaExpr.cpp
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Expand Up @@ -16796,12 +16796,11 @@ ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
LangOpts.CPlusPlus11? diag::ext_offsetof_non_standardlayout_type
: diag::ext_offsetof_non_pod_type;

if (!IsSafe && !DidWarnAboutNonPOD &&
DiagRuntimeBehavior(BuiltinLoc, nullptr,
PDiag(DiagID)
<< SourceRange(Components[0].LocStart, OC.LocEnd)
<< CurrentType))
if (!IsSafe && !DidWarnAboutNonPOD && !isUnevaluatedContext()) {
Diag(BuiltinLoc, DiagID)
<< SourceRange(Components[0].LocStart, OC.LocEnd) << CurrentType;
DidWarnAboutNonPOD = true;
}
}

// Look for the field.
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62 changes: 31 additions & 31 deletions clang/test/SemaCXX/class-layout.cpp
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@@ -1,34 +1,34 @@
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-c++11-extensions
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=16 -DCLANG_ABI_COMPAT=16
// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15

// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-c++11-extensions
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=16 -DCLANG_ABI_COMPAT=16
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-invalid-offsetof -Wno-c++11-extensions
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=16 -DCLANG_ABI_COMPAT=16
// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15
// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15

// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-c++11-extensions -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=6 -DCLANG_ABI_COMPAT=6 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=14 -DCLANG_ABI_COMPAT=14 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=16 -DCLANG_ABI_COMPAT=16 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -fclang-abi-compat=15 -DCLANG_ABI_COMPAT=15 -Wno-invalid-offsetof



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6 changes: 3 additions & 3 deletions clang/test/SemaCXX/ms_struct.cpp
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Expand Up @@ -25,6 +25,7 @@ struct B : public A {

static_assert(__builtin_offsetof(B, d) == 12,
"We can't allocate the bitfield into the padding under ms_struct");
// expected-warning@-2 {{offset of on non-standard-layout type 'B'}}
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I think this diagnostic is an improvement over the status quo.


struct C {
#ifdef TEST_FOR_ERROR
Expand All @@ -38,6 +39,5 @@ struct C {

static_assert(__builtin_offsetof(C, n) == 8,
"long long field in ms_struct should be 8-byte aligned");
#if !defined(TEST_FOR_ERROR) && !defined(TEST_FOR_WARNING)
// expected-no-diagnostics
#endif
// expected-warning@-2 {{offset of on non-standard-layout type 'C'}}

9 changes: 5 additions & 4 deletions clang/test/SemaCXX/offsetof.cpp
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Expand Up @@ -51,9 +51,9 @@ struct Derived2 : public Base1, public Base2 {
int z;
};

int derived1[__builtin_offsetof(Derived2, x) == 0? 1 : -1];
int derived2[__builtin_offsetof(Derived2, y) == 4? 1 : -1];
int derived3[__builtin_offsetof(Derived2, z) == 8? 1 : -1];
int derived1[__builtin_offsetof(Derived2, x) == 0? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
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This also seems like an improvement in diagnostic behavior.

int derived2[__builtin_offsetof(Derived2, y) == 4? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
int derived3[__builtin_offsetof(Derived2, z) == 8? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}

// offsetof referring to anonymous struct in base.
// PR7769
Expand All @@ -66,7 +66,8 @@ struct foo {
struct bar : public foo {
};

int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1];
int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1]; // expected-warning{{offset of on non-POD type 'bar'}}


struct LtoRCheck {
int a[10];
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5 changes: 5 additions & 0 deletions libcxx/include/__type_traits/datasizeof.h
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Expand Up @@ -47,7 +47,12 @@ struct __libcpp_datasizeof {
};
#endif

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Optional : Can you add a brief comment/note that why warnings are suppressed here?
Mb something like :

// Disable warnings related to the use of `offsetof` on non-standard layout types 
// TODO : Find a way to replace offsetof ?

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Done. Thanks

// _FirstPaddingByte<> is sometimes non-standard layout. Using `offsetof` is UB in that case, but GCC and Clang allow
// the use as an extension.
_LIBCPP_DIAGNOSTIC_PUSH
_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
static const size_t value = offsetof(_FirstPaddingByte<>, __first_padding_byte_);
_LIBCPP_DIAGNOSTIC_POP
};

_LIBCPP_END_NAMESPACE_STD
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2 changes: 1 addition & 1 deletion libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/non_trivial_copy_move_ABI.pass.cpp
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Expand Up @@ -17,7 +17,7 @@
// Test that we provide the non-trivial copy operations when _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
// is specified.
// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
// ADDITIONAL_COMPILE_FLAGS: -Wno-macro-redefined
// ADDITIONAL_COMPILE_FLAGS: -Wno-macro-redefined -Wno-invalid-offsetof

#include <utility>
#include <type_traits>
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1 change: 1 addition & 0 deletions libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/trivial_copy_move_ABI.pass.cpp
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Expand Up @@ -14,6 +14,7 @@

// FreeBSD still provides the old ABI for std::pair.
// XFAIL: freebsd
// ADDITIONAL_COMPILE_FLAGS: -Wno-invalid-offsetof

#include <utility>
#include <type_traits>
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