| commit 2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84 |
| Author: Nathan Chancellor <natechancellor@gmail.com> |
| Date: Sat Mar 7 16:37:44 2020 -0800 |
| |
| [Sema] Add -Wpointer-to-enum-cast and -Wvoid-pointer-to-enum-cast |
| |
| GCC does not warn on casts from pointers to enumerators, while clang |
| currently does: https://godbolt.org/z/3DFDVG |
| |
| This causes a bunch of extra warnings in the Linux kernel, where |
| certain structs contain a void pointer to avoid using a gigantic |
| union for all of the various types of driver data, such as |
| versions. |
| |
| Add a diagnostic that allows certain projects like the kernel to |
| disable the warning just for enums, which allows those projects to |
| keep full compatibility with GCC but keeps the intention of treating |
| casts to integers and enumerators the same by default so that other |
| projects have the opportunity to catch issues not noticed before (or |
| follow suite and disable the warning). |
| |
| Link: https://github.com/ClangBuiltLinux/linux/issues/887 |
| |
| Reviewed By: rjmccall |
| |
| Differential Revision: https://reviews.llvm.org/D75758 |
| |
| diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td |
| index 6c79ea59173..ae3f882dd91 100644 |
| --- a/clang/include/clang/Basic/DiagnosticGroups.td |
| +++ b/clang/include/clang/Basic/DiagnosticGroups.td |
| @@ -838,9 +838,13 @@ def IncompatibleExceptionSpec : DiagGroup<"incompatible-exception-spec">; |
| def IntToVoidPointerCast : DiagGroup<"int-to-void-pointer-cast">; |
| def IntToPointerCast : DiagGroup<"int-to-pointer-cast", |
| [IntToVoidPointerCast]>; |
| -def VoidPointerToIntCast : DiagGroup<"void-pointer-to-int-cast">; |
| +def VoidPointerToEnumCast : DiagGroup<"void-pointer-to-enum-cast">; |
| +def VoidPointerToIntCast : DiagGroup<"void-pointer-to-int-cast", |
| + [VoidPointerToEnumCast]>; |
| +def PointerToEnumCast : DiagGroup<"pointer-to-enum-cast", |
| + [VoidPointerToEnumCast]>; |
| def PointerToIntCast : DiagGroup<"pointer-to-int-cast", |
| - [VoidPointerToIntCast]>; |
| + [PointerToEnumCast, VoidPointerToIntCast]>; |
| |
| def Move : DiagGroup<"move", [ |
| PessimizingMove, |
| diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td |
| index 181341fed78..b0338c44cca 100644 |
| --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td |
| +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td |
| @@ -3668,9 +3668,15 @@ def warn_int_to_void_pointer_cast : Warning< |
| def warn_pointer_to_int_cast : Warning< |
| "cast to smaller integer type %1 from %0">, |
| InGroup<PointerToIntCast>; |
| +def warn_pointer_to_enum_cast : Warning< |
| + warn_pointer_to_int_cast.Text>, |
| + InGroup<PointerToEnumCast>; |
| def warn_void_pointer_to_int_cast : Warning< |
| "cast to smaller integer type %1 from %0">, |
| InGroup<VoidPointerToIntCast>; |
| +def warn_void_pointer_to_enum_cast : Warning< |
| + warn_void_pointer_to_int_cast.Text>, |
| + InGroup<VoidPointerToEnumCast>; |
| def ext_ms_pointer_to_int_cast : ExtWarn< |
| "cast to smaller integer type %1 from %0 is a Microsoft extension">, |
| InGroup<MicrosoftCast>; |
| diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp |
| index 17d07c57a41..8edff2439e0 100644 |
| --- a/clang/lib/Sema/SemaCast.cpp |
| +++ b/clang/lib/Sema/SemaCast.cpp |
| @@ -2777,11 +2777,16 @@ void CastOperation::CheckCStyleCast() { |
| // If the result cannot be represented in the integer type, the behavior |
| // is undefined. The result need not be in the range of values of any |
| // integer type. |
| - unsigned Diag = Self.getLangOpts().MicrosoftExt |
| - ? diag::ext_ms_pointer_to_int_cast |
| - : SrcType->isVoidPointerType() |
| - ? diag::warn_void_pointer_to_int_cast |
| - : diag::warn_pointer_to_int_cast; |
| + unsigned Diag; |
| + if (Self.getLangOpts().MicrosoftExt) |
| + Diag = diag::ext_ms_pointer_to_int_cast; |
| + else if (SrcType->isVoidPointerType()) |
| + Diag = DestType->isEnumeralType() ? diag::warn_void_pointer_to_enum_cast |
| + : diag::warn_void_pointer_to_int_cast; |
| + else if (DestType->isEnumeralType()) |
| + Diag = diag::warn_pointer_to_enum_cast; |
| + else |
| + Diag = diag::warn_pointer_to_int_cast; |
| Self.Diag(OpRange.getBegin(), Diag) << SrcType << DestType << OpRange; |
| } |
| } |
| diff --git a/clang/test/Sema/cast.c b/clang/test/Sema/cast.c |
| index 0c4fc7d129f..2335f219807 100644 |
| --- a/clang/test/Sema/cast.c |
| +++ b/clang/test/Sema/cast.c |
| @@ -186,3 +186,23 @@ void *intToPointerCast2(X x) { |
| void *intToPointerCast3() { |
| return (void*)(1 + 3); |
| } |
| + |
| +void voidPointerToEnumCast(VoidPtr v) { |
| + (void)(X) v; // expected-warning{{cast to smaller integer type 'X' from 'VoidPtr' (aka 'void *')}} |
| + // Test that casts to void* can be controlled separately |
| + // from other -Wpointer-to-enum-cast warnings. |
| +#pragma clang diagnostic push |
| +#pragma clang diagnostic ignored "-Wvoid-pointer-to-enum-cast" |
| + (void)(X) v; // no-warning |
| +#pragma clang diagnostic pop |
| +} |
| + |
| +void pointerToEnumCast(CharPtr v) { |
| + (void)(X) v; // expected-warning{{cast to smaller integer type 'X' from 'CharPtr' (aka 'char *')}} |
| + // Test that casts to void* can be controlled separately |
| + // from other -Wpointer-to-enum-cast warnings. |
| +#pragma clang diagnostic push |
| +#pragma clang diagnostic ignored "-Wvoid-pointer-to-enum-cast" |
| + (void)(X) v; // expected-warning{{cast to smaller integer type 'X' from 'CharPtr' (aka 'char *')}} |
| +#pragma clang diagnostic pop |
| +} |
