diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def index 5ad9c1f24b7c5..a6f36b23f07dc 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -520,6 +520,9 @@ BENIGN_LANGOPT(CheckNew, 1, 0, "Do not assume C++ operator new may not return NU BENIGN_LANGOPT(CheckConstexprFunctionBodies, 1, 1, "Emit diagnostics for a constexpr function body that can never " "be used in a constant expression.") + +LANGOPT(BoundsSafety, 1, 0, "Bounds safety extension for C") + #undef LANGOPT #undef COMPATIBLE_LANGOPT #undef BENIGN_LANGOPT diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index fecfa2f3c7dba..5229940ec8258 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -1911,6 +1911,14 @@ def fapinotes_swift_version : Joined<["-"], "fapinotes-swift-version=">, MetaVarName<"">, HelpText<"Specify the Swift version to use when filtering API notes">; +defm bounds_safety : BoolFOption< + "experimental-bounds-safety", + LangOpts<"BoundsSafety">, DefaultFalse, + PosFlag, + NegFlag, + BothFlags<[], [CC1Option], + " experimental bounds safety extension for C">>; + defm addrsig : BoolFOption<"addrsig", CodeGenOpts<"Addrsig">, DefaultFalse, PosFlag, diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp index 41295bfb3b94f..f2f3bfcd09035 100644 --- a/clang/lib/Sema/SemaDeclAttr.cpp +++ b/clang/lib/Sema/SemaDeclAttr.cpp @@ -5948,7 +5948,7 @@ CheckCountedByAttrOnField(Sema &S, FieldDecl *FD, Expr *E, } else if (PointeeTy->isFunctionType()) { InvalidTypeKind = CountedByInvalidPointeeTypeKind::FUNCTION; } else if (PointeeTy->isStructureTypeWithFlexibleArrayMember()) { - if (FieldTy->isArrayType()) { + if (FieldTy->isArrayType() && !S.getLangOpts().BoundsSafety) { // This is a workaround for the Linux kernel that has already adopted // `counted_by` on a FAM where the pointee is a struct with a FAM. This // should be an error because computing the bounds of the array cannot be diff --git a/clang/test/Sema/attr-counted-by-bounds-safety-vlas.c b/clang/test/Sema/attr-counted-by-bounds-safety-vlas.c new file mode 100644 index 0000000000000..7d9c9a90880ff --- /dev/null +++ b/clang/test/Sema/attr-counted-by-bounds-safety-vlas.c @@ -0,0 +1,37 @@ +// RUN: %clang_cc1 -fsyntax-only -fexperimental-bounds-safety -verify %s +// +// This is a portion of the `attr-counted-by-vla.c` test but is checked +// under the semantics of `-fexperimental-bounds-safety` which has different +// behavior. + +#define __counted_by(f) __attribute__((counted_by(f))) + +struct has_unannotated_VLA { + int count; + char buffer[]; +}; + +struct has_annotated_VLA { + int count; + char buffer[] __counted_by(count); +}; + +struct buffer_of_structs_with_unnannotated_vla { + int count; + // expected-error@+1{{'counted_by' cannot be applied to an array with element of unknown size because 'struct has_unannotated_VLA' is a struct type with a flexible array member}} + struct has_unannotated_VLA Arr[] __counted_by(count); +}; + + +struct buffer_of_structs_with_annotated_vla { + int count; + // expected-error@+1{{'counted_by' cannot be applied to an array with element of unknown size because 'struct has_annotated_VLA' is a struct type with a flexible array member}} + struct has_annotated_VLA Arr[] __counted_by(count); +}; + +struct buffer_of_const_structs_with_annotated_vla { + int count; + // Make sure the `const` qualifier is printed when printing the element type. + // expected-error@+1{{'counted_by' cannot be applied to an array with element of unknown size because 'const struct has_annotated_VLA' is a struct type with a flexible array member}} + const struct has_annotated_VLA Arr[] __counted_by(count); +};