On Tue, 12 Dec 2023 at 21:45, <mjsbea...@gmail.com> wrote:
>
> From: Mikhail Krichanov <mikhailkricha...@gmail.com>
>
> Provides a variant of the DEBUG macro for clang when MDEPKG_NDEBUG is
> defined, which uses but discards the contained expression. This means
> clang can tell that it has optimised away variable usage as part of
> valid debug patterns (such as a STATIC variable which is only used in
> DEBUG statements) - rather than just seeing such variables as
> completely unused - therefore we can keep
> -Wunneeded-internal-declaration (as part of -Wall) to warn about
> mistakenly genuinely unused variables elsewhere.
>
> Note that the _Pragma in the clang/gcc variant is to temporarily
> suppress the warning about `(VOID) Expression;`, whilst the presence
> of `(VOID) Expression;` (once allowed) is what prevents the unwanted
> warning about unneeded variables.
>
> Signed-off-by: Mikhail Krichanov <mikhailkricha...@gmail.com>
> Signed-off-by: Mike Beaton <mjsbea...@gmail.com>
> ---
> BaseTools/Conf/tools_def.template | 2 +-
> MdePkg/Include/Library/DebugLib.h | 10 ++++++++++
> 2 files changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/BaseTools/Conf/tools_def.template
> b/BaseTools/Conf/tools_def.template
> index c34ecfd557..eaccf0b698 100755
> --- a/BaseTools/Conf/tools_def.template
> +++ b/BaseTools/Conf/tools_def.template
> @@ -1859,7 +1859,7 @@ DEFINE CLANGDWARF_X64_DLINK2_FLAGS =
> -Wl,--defsym=PECOFF_HEADER_SIZE=0x22
> DEFINE CLANGDWARF_IA32_TARGET = -target i686-pc-linux-gnu
> DEFINE CLANGDWARF_X64_TARGET = -target x86_64-pc-linux-gnu
>
> -DEFINE CLANGDWARF_WARNING_OVERRIDES = -Wno-parentheses-equality
> -Wno-empty-body -Wno-unused-const-variable -Wno-varargs
> -Wno-unknown-warning-option -Wno-unused-but-set-variable
> -Wno-unused-const-variable -Wno-unaligned-access
> -Wno-unneeded-internal-declaration
> +DEFINE CLANGDWARF_WARNING_OVERRIDES = -Wno-parentheses-equality
> -Wno-empty-body -Wno-unused-const-variable -Wno-varargs
> -Wno-unknown-warning-option -Wno-unused-but-set-variable
> -Wno-unused-const-variable -Wno-unaligned-access
> DEFINE CLANGDWARF_ALL_CC_FLAGS = DEF(GCC48_ALL_CC_FLAGS)
> DEF(CLANGDWARF_WARNING_OVERRIDES) -fno-stack-protector -mms-bitfields
> -Wno-address -Wno-shift-negative-value -Wno-unknown-pragmas
> -Wno-incompatible-library-redeclaration -fno-asynchronous-unwind-tables
> -mno-sse -mno-mmx -msoft-float -mno-implicit-float
> -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang
> -funsigned-char -fno-ms-extensions -Wno-null-dereference
>
> ###########################
> diff --git a/MdePkg/Include/Library/DebugLib.h
> b/MdePkg/Include/Library/DebugLib.h
> index 40772f2e0f..7368004f46 100644
> --- a/MdePkg/Include/Library/DebugLib.h
> +++ b/MdePkg/Include/Library/DebugLib.h
> @@ -425,6 +425,16 @@ UnitTestDebugAssert (
> _DEBUG (Expression); \
> } \
> } while (FALSE)
> +#elif defined (__GNUC__) || defined (__clang__)
> +#define DEBUG(Expression) \
> + do { \
> + _Pragma("GCC diagnostic push") \
> + _Pragma("GCC diagnostic ignored \"-Wunused-value\"") \
> + if ((FALSE)) { \
> + (VOID) Expression; \
> + } \
> + _Pragma("GCC diagnostic pop") \
> + } while (FALSE)
> #else
> #define DEBUG(Expression)
> #endif
> --
> 2.39.2
>
Hi Mikhail,
Are you okay to reply confirming that you're happy with your
Signed-off-by in the above?
Thanks,
Mike
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