For code style purposes, I suggest to declare the first member of the language list as a third argument, process it, and then use it to get the following from the VA. Also, I think you forgot to CC the MdePkg maintainers, so I did with this mail.
Regards, Marvin. > -----Original Message----- > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of > Zenith432 > Sent: Saturday, December 9, 2017 8:44 PM > To: edk2-devel@lists.01.org > Subject: [edk2] [PATCH] MdePkg: resolve bug 741 > > This is a proposal to resolve bug 741: UefiLib.c compilation failure with > clang > error: passing an object that undergoes default argument promotion to > 'va_start' has undefined behavior [-Werror,-Wvarargs]" > > Rationale: > 1. Default argument promotion causes the sizeof a function's argument to be > different than the corresponding parameter's sizeof. This may break a > permissible implemenation of stdarg.h, which is why it is considered > undefined behavior in C. The condition should be repaired rather than > silenced with -Wno-varargs. > 2. The warning is due to the last non-variadic parameter of GetBestLanguage > having type BOOLEAN. > 3. BOOLEAN is typedef'd to 'unsigned char' in all ProcessorBind.h. > 4. 'unsigned char' goes default argument promotion to int. > 5. All ProcessorBind.h typedef the type INT32 to either 'int' or some 32-bit > equivalent. > 6. As a result it is safe to replace the type of the parameter from BOOLEAN to > INT32 in all current supported architectures. > 7. The change is consistent with the BOOLEAN argument being converted to > INT32 at the caller site. The function GetBestLanguage currently converts the > argument from INT32 back to BOOLEAN, however the function's logic is not > disturbed by treating the argument as an INT32. > > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Zenith432 <zenith...@users.sourceforge.net> > --- > MdePkg/Include/Library/UefiLib.h | 2 +- MdePkg/Library/UefiLib/UefiLib.c > | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/MdePkg/Include/Library/UefiLib.h > b/MdePkg/Include/Library/UefiLib.h > index 0b14792a..5d98eb26 100644 > --- a/MdePkg/Include/Library/UefiLib.h > +++ b/MdePkg/Include/Library/UefiLib.h > @@ -818,7 +818,7 @@ CHAR8 * > EFIAPI > GetBestLanguage ( > IN CONST CHAR8 *SupportedLanguages, > - IN BOOLEAN Iso639Language, > + IN INT32 Iso639Language, > ... > ); > > diff --git a/MdePkg/Library/UefiLib/UefiLib.c > b/MdePkg/Library/UefiLib/UefiLib.c > index a7eee012..57236511 100644 > --- a/MdePkg/Library/UefiLib/UefiLib.c > +++ b/MdePkg/Library/UefiLib/UefiLib.c > @@ -1514,7 +1514,7 @@ CHAR8 * > EFIAPI > GetBestLanguage ( > IN CONST CHAR8 *SupportedLanguages, > - IN BOOLEAN Iso639Language, > + IN INT32 Iso639Language, > ... > ) > { > -- > 2.14.3 (Apple Git-98) > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
