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[Clang] Fix missing diagnostic for non-standard layout type in offsetof (#65246)
Fixes #64619 Clang warns diagnostic for non-standard layout types in `offsetof` only if they are in evaluated context. With this patch, you'll also get diagnostic if you use `offsetof` on non-standard layout types in any other contexts
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-44
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8 files changed

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‎clang/docs/ReleaseNotes.rst

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Original file line numberDiff line numberDiff line change
@@ -298,6 +298,8 @@ Improvements to Clang's diagnostics
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source:1:24: note: expression evaluates to ''\n' (0x0A, 10) == U'🌍' (0x1F30D, 127757)'
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1 | static_assert("A\n"[1] == U'🌍');
300300
| ~~~~~~~~~^~~~~~~~
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- Clang now always diagnoses when using non-standard layout types in ``offsetof`` .
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(`#64619: <https://github.com/llvm/llvm-project/issues/64619>`_)
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302304
Bug Fixes in This Version
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-------------------------

‎clang/lib/Sema/SemaExpr.cpp

Lines changed: 4 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -16796,12 +16796,11 @@ ExprResult Sema::BuildBuiltinOffsetOf(SourceLocation BuiltinLoc,
1679616796
LangOpts.CPlusPlus11? diag::ext_offsetof_non_standardlayout_type
1679716797
: diag::ext_offsetof_non_pod_type;
1679816798

16799-
if (!IsSafe && !DidWarnAboutNonPOD &&
16800-
DiagRuntimeBehavior(BuiltinLoc, nullptr,
16801-
PDiag(DiagID)
16802-
<< SourceRange(Components[0].LocStart, OC.LocEnd)
16803-
<< CurrentType))
16799+
if (!IsSafe && !DidWarnAboutNonPOD && !isUnevaluatedContext()) {
16800+
Diag(BuiltinLoc, DiagID)
16801+
<< SourceRange(Components[0].LocStart, OC.LocEnd) << CurrentType;
1680416802
DidWarnAboutNonPOD = true;
16803+
}
1680516804
}
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1680716806
// Look for the field.

‎clang/test/SemaCXX/class-layout.cpp

Lines changed: 31 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -1,34 +1,34 @@
1-
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++98 -Wno-inaccessible-base -Wno-c++11-extensions
2-
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
3-
// RUN: %clang_cc1 -triple x86_64-apple-darwin %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
4-
// RUN: %clang_cc1 -triple x86_64-scei-ps4 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
5-
// RUN: %clang_cc1 -triple x86_64-sie-ps5 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=6
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
7-
// 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
8-
// 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
9-
// 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
10-
// RUN: %clang_cc1 -triple powerpc-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
11-
// 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
12-
// RUN: %clang_cc1 -triple powerpc64-ibm-aix7.3.0.0 %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -DCLANG_ABI_COMPAT=15
13-
// 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
14-
// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
15-
// 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
16-
17-
// 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
18-
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
19-
// 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
20-
// 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
21-
// 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
22-
// 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
23-
// 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
24-
// 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
25-
// 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
26-
// 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
27-
// 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
28-
// 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
29-
// 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
30-
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
31-
// 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
1+
// 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
2+
// RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
3+
// 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
4+
// 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
5+
// 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
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
7+
// 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
8+
// 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
9+
// 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
10+
// 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
11+
// 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
12+
// 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
13+
// 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
14+
// RUN: %clang_cc1 -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
15+
// 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
16+
17+
// 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
18+
// 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
19+
// 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
20+
// 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
21+
// 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
22+
// 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
23+
// 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
24+
// 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
25+
// 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
26+
// 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
27+
// 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
28+
// 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
29+
// 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
30+
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple s390x-none-zos %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base -Wno-invalid-offsetof
31+
// 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
3232

3333

3434

‎clang/test/SemaCXX/ms_struct.cpp

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -25,6 +25,7 @@ struct B : public A {
2525

2626
static_assert(__builtin_offsetof(B, d) == 12,
2727
"We can't allocate the bitfield into the padding under ms_struct");
28+
// expected-warning@-2 {{offset of on non-standard-layout type 'B'}}
2829

2930
struct C {
3031
#ifdef TEST_FOR_ERROR
@@ -38,6 +39,5 @@ struct C {
3839

3940
static_assert(__builtin_offsetof(C, n) == 8,
4041
"long long field in ms_struct should be 8-byte aligned");
41-
#if !defined(TEST_FOR_ERROR) && !defined(TEST_FOR_WARNING)
42-
// expected-no-diagnostics
43-
#endif
42+
// expected-warning@-2 {{offset of on non-standard-layout type 'C'}}
43+

‎clang/test/SemaCXX/offsetof.cpp

Lines changed: 5 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -51,9 +51,9 @@ struct Derived2 : public Base1, public Base2 {
5151
int z;
5252
};
5353

54-
int derived1[__builtin_offsetof(Derived2, x) == 0? 1 : -1];
55-
int derived2[__builtin_offsetof(Derived2, y) == 4? 1 : -1];
56-
int derived3[__builtin_offsetof(Derived2, z) == 8? 1 : -1];
54+
int derived1[__builtin_offsetof(Derived2, x) == 0? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
55+
int derived2[__builtin_offsetof(Derived2, y) == 4? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
56+
int derived3[__builtin_offsetof(Derived2, z) == 8? 1 : -1]; // expected-warning{{offset of on non-POD type 'Derived2'}}
5757

5858
// offsetof referring to anonymous struct in base.
5959
// PR7769
@@ -66,7 +66,8 @@ struct foo {
6666
struct bar : public foo {
6767
};
6868

69-
int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1];
69+
int anonstruct[__builtin_offsetof(bar, x) == 0 ? 1 : -1]; // expected-warning{{offset of on non-POD type 'bar'}}
70+
7071

7172
struct LtoRCheck {
7273
int a[10];

‎libcxx/include/__type_traits/datasizeof.h

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -47,7 +47,12 @@ struct __libcpp_datasizeof {
4747
};
4848
#endif
4949

50+
// _FirstPaddingByte<> is sometimes non-standard layout. Using `offsetof` is UB in that case, but GCC and Clang allow
51+
// the use as an extension.
52+
_LIBCPP_DIAGNOSTIC_PUSH
53+
_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
5054
static const size_t value = offsetof(_FirstPaddingByte<>, __first_padding_byte_);
55+
_LIBCPP_DIAGNOSTIC_POP
5156
};
5257

5358
_LIBCPP_END_NAMESPACE_STD

‎libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/non_trivial_copy_move_ABI.pass.cpp

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -17,7 +17,7 @@
1717
// Test that we provide the non-trivial copy operations when _LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
1818
// is specified.
1919
// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DEPRECATED_ABI_DISABLE_PAIR_TRIVIAL_COPY_CTOR
20-
// ADDITIONAL_COMPILE_FLAGS: -Wno-macro-redefined
20+
// ADDITIONAL_COMPILE_FLAGS: -Wno-macro-redefined -Wno-invalid-offsetof
2121

2222
#include <utility>
2323
#include <type_traits>

‎libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/trivial_copy_move_ABI.pass.cpp

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -14,6 +14,7 @@
1414

1515
// FreeBSD still provides the old ABI for std::pair.
1616
// XFAIL: freebsd
17+
// ADDITIONAL_COMPILE_FLAGS: -Wno-invalid-offsetof
1718

1819
#include <utility>
1920
#include <type_traits>

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