[clang] [Clang] Fix missing diagnostic for non-standard layout type in `offsetof` (PR #65246)
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Thu Sep 28 02:12:23 PDT 2023
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-libcxx
<details>
<summary>Changes</summary>
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
---
Full diff: https://github.com/llvm/llvm-project/pull/65246.diff
6 Files Affected:
- (modified) clang/docs/ReleaseNotes.rst (+2)
- (modified) clang/lib/Sema/SemaExpr.cpp (+4-5)
- (modified) clang/test/SemaCXX/class-layout.cpp (+15-15)
- (modified) clang/test/SemaCXX/ms_struct.cpp (+3-3)
- (modified) clang/test/SemaCXX/offsetof.cpp (+5-4)
- (modified) libcxx/include/__type_traits/datasizeof.h (+4)
``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f314c9c72fa28b7..abc36bac05d788d 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -208,6 +208,8 @@ Improvements to Clang's diagnostics
(`#54678: <https://github.com/llvm/llvm-project/issues/54678>`_).
- Clang now prints its 'note' diagnostic in cyan instead of black, to be more compatible
with terminals with dark background colors. This is also more consistent with GCC.
+- 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
-------------------------
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 92496b03ecabe54..fedea932c5e15fe 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -16766,12 +16766,11 @@ 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.
diff --git a/clang/test/SemaCXX/class-layout.cpp b/clang/test/SemaCXX/class-layout.cpp
index 9782ff08100b2d6..23b3dbe24249378 100644
--- a/clang/test/SemaCXX/class-layout.cpp
+++ b/clang/test/SemaCXX/class-layout.cpp
@@ -1,18 +1,18 @@
-// 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 -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
// RUN: %clang_cc1 -fexperimental-new-constant-interpreter -triple x86_64-unknown-unknown %s -fsyntax-only -verify -std=c++11 -Wno-inaccessible-base
diff --git a/clang/test/SemaCXX/ms_struct.cpp b/clang/test/SemaCXX/ms_struct.cpp
index e6f0a25b38ea80c..995e424d1f87640 100644
--- a/clang/test/SemaCXX/ms_struct.cpp
+++ b/clang/test/SemaCXX/ms_struct.cpp
@@ -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 at -2 {{offset of on non-standard-layout type 'B'}}
struct C {
#ifdef TEST_FOR_ERROR
@@ -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 at -2 {{offset of on non-standard-layout type 'C'}}
+
diff --git a/clang/test/SemaCXX/offsetof.cpp b/clang/test/SemaCXX/offsetof.cpp
index c984657ebe1f0ed..c4e86369f007dcb 100644
--- a/clang/test/SemaCXX/offsetof.cpp
+++ b/clang/test/SemaCXX/offsetof.cpp
@@ -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'}}
+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
@@ -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];
diff --git a/libcxx/include/__type_traits/datasizeof.h b/libcxx/include/__type_traits/datasizeof.h
index 019099a9cf183b5..88a702470c3c15a 100644
--- a/libcxx/include/__type_traits/datasizeof.h
+++ b/libcxx/include/__type_traits/datasizeof.h
@@ -47,7 +47,11 @@ struct __libcpp_datasizeof {
};
#endif
+ _LIBCPP_DIAGNOSTIC_PUSH
+ _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
+ _LIBCPP_GCC_DIAGNOSTIC_IGNORED("-Winvalid-offsetof")
static const size_t value = offsetof(_FirstPaddingByte<>, __first_padding_byte_);
+ _LIBCPP_DIAGNOSTIC_POP
};
_LIBCPP_END_NAMESPACE_STD
``````````
</details>
https://github.com/llvm/llvm-project/pull/65246
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