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---------- Forwarded message ---------- From: mats petersson <[email protected]> Date: 15 December 2014 at 08:40 Subject: Re: [PATCH] Introduce __BIGGEST_ALIGNMENT__ macro To: Reid Kleckner <[email protected]> On 15 December 2014 at 06:41, Reid Kleckner <[email protected]> wrote: > Is there a compelling reason to use __BIGGEST_ALIGNMENT__ over max_align_t? You mean aside from `max_align_t` not being possible to evaluate at preprocessor time? Then no. If you want to see alignment at preprocessor time, then there is a good reason. -- Mats > > On Sat, Dec 13, 2014 at 9:51 AM, mats petersson <[email protected]> > wrote: >> >> This is my first attempt for a patch to Clang, so please accept my >> apologies for any misconduct with regards to formatting, styling, >> content, culture, etc - and I hope that gmail doesn't munge the >> patch... >> >> The idea for this came about when at work (ARM) we discussed some code >> that had accidentally aligned it's sub-allocated block to 4 bytes for >> a 64-bit type, and got a unaligned access trap. So "how do you know", >> and someone found __BIGGEST_ALIGNMENT__ in gcc - but not available for >> Clang. So I thought I could add it, to make it a little more >> consistent between compilers... >> >> -- >> Mats >> >> Add a predefined macro reflecting the largest alignment required by >> the archiecture, in bytes. This is useful for allocator designs that >> need to know the system alignment requirements. It reflects the >> TargetInfo.SuitableAlignment, converted to bytes (using CharWidth). >> --- >> lib/Frontend/InitPreprocessor.cpp | 4 ++++ >> test/Preprocessor/init.c | 33 >> +++++++++++++++++++++++++++++++++ >> 2 files changed, 37 insertions(+), 0 deletions(-) >> >> diff --git a/lib/Frontend/InitPreprocessor.cpp >> b/lib/Frontend/InitPreprocessor.cpp >> index f4241a9..896277a 100644 >> --- a/lib/Frontend/InitPreprocessor.cpp >> +++ b/lib/Frontend/InitPreprocessor.cpp >> @@ -710,6 +710,10 @@ static void InitializePredefinedMacros(const >> TargetInfo &TI, >> Builder.defineMacro("__POINTER_WIDTH__", >> Twine((int)TI.getPointerWidth(0))); >> >> + // Define __BIGGEST_ALIGNMENT__ to be compatible with gcc. >> + Builder.defineMacro("__BIGGEST_ALIGNMENT__", >> + Twine(TI.getSuitableAlign() / TI.getCharWidth()) ); >> + >> if (!LangOpts.CharIsSigned) >> Builder.defineMacro("__CHAR_UNSIGNED__"); >> >> diff --git a/test/Preprocessor/init.c b/test/Preprocessor/init.c >> index 4f32114..924aa5b 100644 >> --- a/test/Preprocessor/init.c >> +++ b/test/Preprocessor/init.c >> @@ -241,6 +241,7 @@ >> // AARCH64:#define __ARM_ARCH 8 >> // AARCH64:#define __ARM_ARCH_ISA_A64 1 >> // AARCH64-NOT:#define __ARM_BIG_ENDIAN 1 >> +// AARCH64:#define __BIGGEST_ALIGNMENT__ 8 >> // AARCH64:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // AARCH64:#define __CHAR16_TYPE__ unsigned short >> // AARCH64:#define __CHAR32_TYPE__ unsigned int >> @@ -431,6 +432,7 @@ >> // AARCH64-BE:#define __ARM_ARCH 8 >> // AARCH64-BE:#define __ARM_ARCH_ISA_A64 1 >> // AARCH64-BE:#define __ARM_BIG_ENDIAN 1 >> +// AARCH64-BE:#define __BIGGEST_ALIGNMENT__ 8 >> // AARCH64-BE:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // AARCH64-BE:#define __CHAR16_TYPE__ unsigned short >> // AARCH64-BE:#define __CHAR32_TYPE__ unsigned int >> @@ -621,6 +623,7 @@ >> // AARCH64-NETBSD:#define __ARM_ARCH 8 >> // AARCH64-NETBSD:#define __ARM_ARCH_ISA_A64 1 >> // AARCH64-NETBSD-NOT:#define __ARM_BIG_ENDIAN 1 >> +// AARCH64-NETBSD:#define __BIGGEST_ALIGNMENT__ 8 >> // AARCH64-NETBSD:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // AARCH64-NETBSD:#define __CHAR16_TYPE__ unsigned short >> // AARCH64-NETBSD:#define __CHAR32_TYPE__ unsigned int >> @@ -812,6 +815,7 @@ >> // AARCH64-FREEBSD:#define __ARM_ARCH 8 >> // AARCH64-FREEBSD:#define __ARM_ARCH_ISA_A64 1 >> // AARCH64-FREEBSD-NOT:#define __ARM_BIG_ENDIAN 1 >> +// AARCH64-FREEBSD:#define __BIGGEST_ALIGNMENT__ 8 >> // AARCH64-FREEBSD:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // AARCH64-FREEBSD:#define __CHAR16_TYPE__ unsigned short >> // AARCH64-FREEBSD:#define __CHAR32_TYPE__ unsigned int >> @@ -1003,6 +1007,7 @@ >> // ARM:#define __ARMEL__ 1 >> // ARM:#define __ARM_ARCH_6J__ 1 >> // ARM-NOT:#define __ARM_BIG_ENDIAN 1 >> +// ARM:#define __BIGGEST_ALIGNMENT__ 8 >> // ARM:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // ARM:#define __CHAR16_TYPE__ unsigned short >> // ARM:#define __CHAR32_TYPE__ unsigned int >> @@ -1193,6 +1198,7 @@ >> // ARM-BE-NOT:#define __ARMEL__ 1 >> // ARM-BE:#define __ARM_ARCH_6J__ 1 >> // ARM-BE:#define __ARM_BIG_ENDIAN 1 >> +// ARM-BE:#define __BIGGEST_ALIGNMENT__ 8 >> // ARM-BE:#define __BIG_ENDIAN__ 1 >> // ARM-BE:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // ARM-BE:#define __CHAR16_TYPE__ unsigned short >> @@ -1387,6 +1393,7 @@ >> // ARMEABISOFTFP:#define __ARM_EABI__ 1 >> // ARMEABISOFTFP:#define __ARM_PCS 1 >> // ARMEABISOFTFP-NOT:#define __ARM_PCS_VFP 1 >> +// ARMEABISOFTFP:#define __BIGGEST_ALIGNMENT__ 8 >> // ARMEABISOFTFP:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // ARMEABISOFTFP:#define __CHAR16_TYPE__ unsigned short >> // ARMEABISOFTFP:#define __CHAR32_TYPE__ unsigned int >> @@ -1582,6 +1589,7 @@ >> // ARMEABIHARDFP:#define __ARM_EABI__ 1 >> // ARMEABIHARDFP:#define __ARM_PCS 1 >> // ARMEABIHARDFP:#define __ARM_PCS_VFP 1 >> +// ARMEABIHARDFP:#define __BIGGEST_ALIGNMENT__ 8 >> // ARMEABIHARDFP:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // ARMEABIHARDFP:#define __CHAR16_TYPE__ unsigned short >> // ARMEABIHARDFP:#define __CHAR32_TYPE__ unsigned int >> @@ -1775,6 +1783,7 @@ >> // ARM-NETBSD:#define __ARM_DWARF_EH__ 1 >> // ARM-NETBSD:#define __ARM_EABI__ 1 >> // ARM-NETBSD-NOT:#define __ARM_BIG_ENDIAN 1 >> +// ARM-NETBSD:#define __BIGGEST_ALIGNMENT__ 8 >> // ARM-NETBSD:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // ARM-NETBSD:#define __CHAR16_TYPE__ unsigned short >> // ARM-NETBSD:#define __CHAR32_TYPE__ unsigned int >> @@ -2021,6 +2030,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=i386-none-none < >> /dev/null | FileCheck -check-prefix I386 %s >> // >> // I386-NOT:#define _LP64 >> +// I386:#define __BIGGEST_ALIGNMENT__ 16 >> // I386:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // I386:#define __CHAR16_TYPE__ unsigned short >> // I386:#define __CHAR32_TYPE__ unsigned int >> @@ -2207,6 +2217,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=i386-pc-linux-gnu >> -target-cpu pentium4 < /dev/null | FileCheck -check-prefix I386-LINUX >> %s >> // >> // I386-LINUX-NOT:#define _LP64 >> +// I386-LINUX:#define __BIGGEST_ALIGNMENT__ 16 >> // I386-LINUX:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // I386-LINUX:#define __CHAR16_TYPE__ unsigned short >> // I386-LINUX:#define __CHAR32_TYPE__ unsigned int >> @@ -2393,6 +2404,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=i386-netbsd < >> /dev/null | FileCheck -check-prefix I386-NETBSD %s >> // >> // I386-NETBSD-NOT:#define _LP64 >> +// I386-NETBSD:#define __BIGGEST_ALIGNMENT__ 16 >> // I386-NETBSD:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // I386-NETBSD:#define __CHAR16_TYPE__ unsigned short >> // I386-NETBSD:#define __CHAR32_TYPE__ unsigned int >> @@ -2597,6 +2609,7 @@ >> // MIPS32BE:#define _MIPS_SZINT 32 >> // MIPS32BE:#define _MIPS_SZLONG 32 >> // MIPS32BE:#define _MIPS_SZPTR 32 >> +// MIPS32BE:#define __BIGGEST_ALIGNMENT__ 8 >> // MIPS32BE:#define __BIG_ENDIAN__ 1 >> // MIPS32BE:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // MIPS32BE:#define __CHAR16_TYPE__ unsigned short >> @@ -2805,6 +2818,7 @@ >> // MIPS32EL:#define _MIPS_SZINT 32 >> // MIPS32EL:#define _MIPS_SZLONG 32 >> // MIPS32EL:#define _MIPS_SZPTR 32 >> +// MIPS32EL:#define __BIGGEST_ALIGNMENT__ 8 >> // MIPS32EL:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // MIPS32EL:#define __CHAR16_TYPE__ unsigned short >> // MIPS32EL:#define __CHAR32_TYPE__ unsigned int >> @@ -3010,6 +3024,7 @@ >> // MIPS64BE:#define _MIPS_SZINT 32 >> // MIPS64BE:#define _MIPS_SZLONG 64 >> // MIPS64BE:#define _MIPS_SZPTR 64 >> +// MIPS64BE:#define __BIGGEST_ALIGNMENT__ 16 >> // MIPS64BE:#define __BIG_ENDIAN__ 1 >> // MIPS64BE:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // MIPS64BE:#define __CHAR16_TYPE__ unsigned short >> @@ -3218,6 +3233,7 @@ >> // MIPS64EL:#define _MIPS_SZINT 32 >> // MIPS64EL:#define _MIPS_SZLONG 64 >> // MIPS64EL:#define _MIPS_SZPTR 64 >> +// MIPS64EL:#define __BIGGEST_ALIGNMENT__ 16 >> // MIPS64EL:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // MIPS64EL:#define __CHAR16_TYPE__ unsigned short >> // MIPS64EL:#define __CHAR32_TYPE__ unsigned int >> @@ -3583,6 +3599,7 @@ >> // >> // MSP430:#define MSP430 1 >> // MSP430-NOT:#define _LP64 >> +// MSP430:#define __BIGGEST_ALIGNMENT__ 2 >> // MSP430:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // MSP430:#define __CHAR16_TYPE__ unsigned short >> // MSP430:#define __CHAR32_TYPE__ unsigned int >> @@ -3766,6 +3783,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=nvptx-none-none < >> /dev/null | FileCheck -check-prefix NVPTX32 %s >> // >> // NVPTX32-NOT:#define _LP64 >> +// NVPTX32:#define __BIGGEST_ALIGNMENT__ 8 >> // NVPTX32:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // NVPTX32:#define __CHAR16_TYPE__ unsigned short >> // NVPTX32:#define __CHAR32_TYPE__ unsigned int >> @@ -3952,6 +3970,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=nvptx64-none-none < >> /dev/null | FileCheck -check-prefix NVPTX64 %s >> // >> // NVPTX64:#define _LP64 1 >> +// NVPTX64:#define __BIGGEST_ALIGNMENT__ 8 >> // NVPTX64:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // NVPTX64:#define __CHAR16_TYPE__ unsigned short >> // NVPTX64:#define __CHAR32_TYPE__ unsigned int >> @@ -4143,6 +4162,7 @@ >> // PPC603E:#define _ARCH_PPCGR 1 >> // PPC603E:#define _BIG_ENDIAN 1 >> // PPC603E-NOT:#define _LP64 >> +// PPC603E:#define __BIGGEST_ALIGNMENT__ 8 >> // PPC603E:#define __BIG_ENDIAN__ 1 >> // PPC603E:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // PPC603E:#define __CHAR16_TYPE__ unsigned short >> @@ -4340,6 +4360,7 @@ >> // PPC64:#define _ARCH_PWR7 1 >> // PPC64:#define _BIG_ENDIAN 1 >> // PPC64:#define _LP64 1 >> +// PPC64:#define __BIGGEST_ALIGNMENT__ 8 >> // PPC64:#define __BIG_ENDIAN__ 1 >> // PPC64:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // PPC64:#define __CHAR16_TYPE__ unsigned short >> @@ -4542,6 +4563,7 @@ >> // PPC64LE:#define _CALL_ELF 2 >> // PPC64LE:#define _LITTLE_ENDIAN 1 >> // PPC64LE:#define _LP64 1 >> +// PPC64LE:#define __BIGGEST_ALIGNMENT__ 8 >> // PPC64LE:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // PPC64LE:#define __CHAR16_TYPE__ unsigned short >> // PPC64LE:#define __CHAR32_TYPE__ unsigned int >> @@ -4923,6 +4945,7 @@ >> // PPC64-LINUX:#define _ARCH_PPC64 1 >> // PPC64-LINUX:#define _BIG_ENDIAN 1 >> // PPC64-LINUX:#define _LP64 1 >> +// PPC64-LINUX:#define __BIGGEST_ALIGNMENT__ 8 >> // PPC64-LINUX:#define __BIG_ENDIAN__ 1 >> // PPC64-LINUX:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // PPC64-LINUX:#define __CHAR16_TYPE__ unsigned short >> @@ -5127,6 +5150,7 @@ >> // PPC:#define _ARCH_PPC 1 >> // PPC:#define _BIG_ENDIAN 1 >> // PPC-NOT:#define _LP64 >> +// PPC:#define __BIGGEST_ALIGNMENT__ 8 >> // PPC:#define __BIG_ENDIAN__ 1 >> // PPC:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // PPC:#define __CHAR16_TYPE__ unsigned short >> @@ -5317,6 +5341,7 @@ >> // PPC-LINUX:#define _ARCH_PPC 1 >> // PPC-LINUX:#define _BIG_ENDIAN 1 >> // PPC-LINUX-NOT:#define _LP64 >> +// PPC-LINUX:#define __BIGGEST_ALIGNMENT__ 8 >> // PPC-LINUX:#define __BIG_ENDIAN__ 1 >> // PPC-LINUX:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // PPC-LINUX:#define __CHAR16_TYPE__ unsigned short >> @@ -5508,6 +5533,7 @@ >> // >> // PPC-DARWIN:#define _ARCH_PPC 1 >> // PPC-DARWIN:#define _BIG_ENDIAN 1 >> +// PPC-DARWIN:#define __BIGGEST_ALIGNMENT__ 16 >> // PPC-DARWIN:#define __BIG_ENDIAN__ 1 >> // PPC-DARWIN:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // PPC-DARWIN:#define __CHAR16_TYPE__ unsigned short >> @@ -5701,6 +5727,7 @@ >> // >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=s390x-none-none >> -fno-signed-char < /dev/null | FileCheck -check-prefix S390X %s >> // >> +// S390X:#define __BIGGEST_ALIGNMENT__ 8 >> // S390X:#define __CHAR16_TYPE__ unsigned short >> // S390X:#define __CHAR32_TYPE__ unsigned int >> // S390X:#define __CHAR_BIT__ 8 >> @@ -5882,6 +5909,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=sparc-none-none < >> /dev/null | FileCheck -check-prefix SPARC %s >> // >> // SPARC-NOT:#define _LP64 >> +// SPARC:#define __BIGGEST_ALIGNMENT__ 8 >> // SPARC:#define __BIG_ENDIAN__ 1 >> // SPARC:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // SPARC:#define __CHAR16_TYPE__ unsigned short >> @@ -6069,6 +6097,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=tce-none-none < >> /dev/null | FileCheck -check-prefix TCE %s >> // >> // TCE-NOT:#define _LP64 >> +// TCE:#define __BIGGEST_ALIGNMENT__ 4 >> // TCE:#define __BIG_ENDIAN__ 1 >> // TCE:#define __BYTE_ORDER__ __ORDER_BIG_ENDIAN__ >> // TCE:#define __CHAR16_TYPE__ unsigned short >> @@ -6236,6 +6265,7 @@ >> // >> // X86_64:#define _LP64 1 >> // X86_64-NOT:#define _LP32 1 >> +// X86_64:#define __BIGGEST_ALIGNMENT__ 16 >> // X86_64:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // X86_64:#define __CHAR16_TYPE__ unsigned short >> // X86_64:#define __CHAR32_TYPE__ unsigned int >> @@ -6437,6 +6467,7 @@ >> // >> // X32:#define _ILP32 1 >> // X32-NOT:#define _LP64 1 >> +// X32:#define __BIGGEST_ALIGNMENT__ 16 >> // X32:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // X32:#define __CHAR16_TYPE__ unsigned short >> // X32:#define __CHAR32_TYPE__ unsigned int >> @@ -6630,6 +6661,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=x86_64-pc-linux-gnu >> < /dev/null | FileCheck -check-prefix X86_64-LINUX %s >> // >> // X86_64-LINUX:#define _LP64 1 >> +// X86_64-LINUX:#define __BIGGEST_ALIGNMENT__ 16 >> // X86_64-LINUX:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // X86_64-LINUX:#define __CHAR16_TYPE__ unsigned short >> // X86_64-LINUX:#define __CHAR32_TYPE__ unsigned int >> @@ -6828,6 +6860,7 @@ >> // RUN: %clang_cc1 -E -dM -ffreestanding -triple=x86_64-netbsd < >> /dev/null | FileCheck -check-prefix X86_64-NETBSD %s >> // >> // X86_64-NETBSD:#define _LP64 1 >> +// X86_64-NETBSD:#define __BIGGEST_ALIGNMENT__ 16 >> // X86_64-NETBSD:#define __BYTE_ORDER__ __ORDER_LITTLE_ENDIAN__ >> // X86_64-NETBSD:#define __CHAR16_TYPE__ unsigned short >> // X86_64-NETBSD:#define __CHAR32_TYPE__ unsigned int >> -- >> 1.7.7.6 >> _______________________________________________ >> cfe-commits mailing list >> [email protected] >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
