From 15ab5382a553a47f21fe7283010ccdb342c0ead6 Mon Sep 17 00:00:00 2001 From: Tony Wasserka Date: Wed, 16 Jul 2014 09:07:57 +0200 Subject: [PATCH] BitField: Delete copy assignment to prevent obscure bugs. Cf. https://github.com/dolphin-emu/dolphin/pull/483 --- src/common/bit_field.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/src/common/bit_field.h b/src/common/bit_field.h index a39bb9886..c28e722c8 100644 --- a/src/common/bit_field.h +++ b/src/common/bit_field.h @@ -124,6 +124,22 @@ public: // so that we can use this within unions BitField() = default; +#ifndef _WIN32 + // We explicitly delete the copy assigment operator here, because the + // default copy assignment would copy the full storage value, rather than + // just the bits relevant to this particular bit field. + // Ideally, we would just implement the copy assignment to copy only the + // relevant bits, but this requires compiler support for unrestricted + // unions. + // MSVC 2013 has no support for this, hence we disable this code on + // Windows (so that the default copy assignment operator will be used). + // For any C++11 conformant compiler we delete the operator to make sure + // we never use this inappropriate operator to begin with. + // TODO: Implement this operator properly once all target compilers + // support unrestricted unions. + BitField& operator=(const BitField&) = delete; +#endif + __forceinline BitField& operator=(T val) { storage = (storage & ~GetMask()) | ((val << position) & GetMask());