[PATCH] Use Clang's __has_* macros in Compiler.h to test for features
Reid Kleckner
rnk at google.com
Mon Jul 8 07:53:29 PDT 2013
On Wed, Jul 3, 2013 at 8:36 AM, Aaron Ballman <aaron at aaronballman.com>wrote:
> > Index: include/llvm/Support/Compiler.h
> > ===================================================================
> > --- include/llvm/Support/Compiler.h
> > +++ include/llvm/Support/Compiler.h
> > @@ -21,6 +21,25 @@
> > # define __has_feature(x) 0
> > #endif
> >
> > +#ifndef __has_attribute
> > +# define __has_attribute(x) 0
> > +#endif
> > +
> > +#ifndef __has_builtin
> > +# define __has_builtin(x) 0
> > +#endif
> > +
> > +/// \macro __GNUC_PREREQ
> > +/// \brief Defines __GNUC_PREREQ if glibc's features.h isn't available.
> > +#ifndef __GNUC_PREREQ
> > +# if defined(__GNUC__) && defined(__GNUC_MINOR__)
> > +# define __GNUC_PREREQ(maj, min) \
> > + ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
> > +# else
> > +# define __GNUC_PREREQ(maj, min) 0
> > +# endif
> > +#endif
> > +
> > /// \brief Does the compiler support r-value references?
> > /// This implies that <utility> provides the one-argument std::move; it
> > /// does not imply the existence of any other C++ library features.
> > @@ -146,13 +165,13 @@
> > /// into a shared library, then the class should be private to the
> library and
> > /// not accessible from outside it. Can also be used to mark variables
> and
> > /// functions, making them private to any shared library they are
> linked into.
> > -#if (__GNUC__ >= 4) && !defined(__MINGW32__) && !defined(__CYGWIN__)
> > +#if __GNUC_PREREQ(4, 0) && !defined(__MINGW32__) && !defined(__CYGWIN__)
>
> __has_attribute(visibility)?
Sure. I didn't change it because my goal is self-hosting clang on Windows,
in which case I don't actually want this define, since library visibility
is the default already. I can probably disable this if LLVM_ON_WIN32.
> > #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
> > #else
> > #define LLVM_LIBRARY_VISIBILITY
> > #endif
> >
> > -#if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
> > +#if __has_attribute(used) || __GNUC_PREREQ(3, 1)
> > #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
> > #else
> > #define LLVM_ATTRIBUTE_USED
> > @@ -166,31 +185,33 @@
> > // more portable solution:
> > // (void)unused_var_name;
> > // Prefer cast-to-void wherever it is sufficient.
> > -#if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
> > +#if __has_attribute(unused) || __GNUC_PREREQ(3, 1)
> > #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
> > #else
> > #define LLVM_ATTRIBUTE_UNUSED
> > #endif
> >
> > -#if (__GNUC__ >= 4) && !defined(__MINGW32__) && !defined(__CYGWIN__)
> > +#if __GNUC_PREREQ(4, 0) && !defined(__MINGW32__) && !defined(__CYGWIN__)
>
> __has_attribute(weak)?
Again, I didn't want the behavior change, so I'll have to turn it off for
win32 explicitly.
> > #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
> > #else
> > #define LLVM_ATTRIBUTE_WEAK
> > #endif
> >
> > -#ifdef __GNUC__ // aka 'CONST' but following LLVM Conventions.
> > +#if __has_attribute(const) || defined(__GNUC__)
> > +// aka 'CONST' but following LLVM Conventions.
> > #define LLVM_READNONE __attribute__((__const__))
> > #else
> > #define LLVM_READNONE
> > #endif
> >
> > -#ifdef __GNUC__ // aka 'PURE' but following LLVM Conventions.
> > +#if __has_attribute(pure) || defined(__GNUC__)
> > +// aka 'PURE' but following LLVM Conventions.
> > #define LLVM_READONLY __attribute__((__pure__))
> > #else
> > #define LLVM_READONLY
> > #endif
> >
> > -#if (__GNUC__ >= 4)
> > +#if __has_builtin(__builtin_expect) || __GNUC_PREREQ(4, 0)
> > #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
> > #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
> > #else
> > @@ -213,7 +234,7 @@
> >
> > /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to
> do so,
> > /// mark a method "not for inlining".
> > -#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
> > +#if __GNUC_PREREQ(3, 4)
>
> __has_attribute(noinline)?
Sure, no harm.
> > #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
> > #elif defined(_MSC_VER)
> > #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
> > @@ -225,7 +246,7 @@
> > /// so, mark a method "always inline" because it is performance
> sensitive. GCC
> > /// 3.4 supported this but is buggy in various cases and produces
> unimplemented
> > /// errors, just use it in GCC 4.0 and later.
> > -#if __GNUC__ > 3
> > +#if __GNUC_PREREQ(3, 0)
>
> __has_attribute(always_inline)
Done.
> > #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline
> __attribute__((always_inline))
> > #elif defined(_MSC_VER)
> > #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
> > @@ -267,27 +288,23 @@
> > /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
> > /// to an expression which states that it is undefined behavior for the
> > /// compiler to reach this point. Otherwise is not defined.
> > -#if defined(__clang__) || (__GNUC__ > 4) \
> > - || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
> > +#if __has_builtin(__builtin_unreachable) || __GNUC_PREREQ(4, 5)
> > # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
> > #elif defined(_MSC_VER)
> > # define LLVM_BUILTIN_UNREACHABLE __assume(false)
> > #endif
> >
> > /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an
> expression
> > /// which causes the program to exit abnormally.
> > -#if defined(__clang__) || (__GNUC__ > 4) \
> > - || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
> > +#if __has_builtin(__builtin_trap) || __GNUC_PREREQ(4, 3)
> > # define LLVM_BUILTIN_TRAP __builtin_trap()
> > #else
> > # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
> > #endif
> >
> > /// \macro LLVM_ASSUME_ALIGNED
> > /// \brief Returns a pointer with an assumed alignment.
> > -#if !defined(__clang__) && ((__GNUC__ > 4) \
> > - || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7))
> > -// FIXME: Enable on clang when it supports it.
> > +#if __has_builtin(__builtin_assume_aligned) && __GNUC_PREREQ(4, 7)
> > # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
> > #elif defined(LLVM_BUILTIN_UNREACHABLE)
> > # define LLVM_ASSUME_ALIGNED(p, a) \
>
> Looks good to me aside from what may or may not be missing
> __has_attribute calls. Thanks!
>
> ~Aaron
>
> On Tue, Jul 2, 2013 at 5:26 PM, Reid Kleckner <rnk at google.com> wrote:
> > - Conditionally define __has_builtin.
> >
> > http://llvm-reviews.chandlerc.com/D1080
> >
> > CHANGE SINCE LAST DIFF
> > http://llvm-reviews.chandlerc.com/D1080?vs=2654&id=2655#toc
> >
> > Files:
> > include/llvm/Support/Compiler.h
> >
> > Index: include/llvm/Support/Compiler.h
> > ===================================================================
> > --- include/llvm/Support/Compiler.h
> > +++ include/llvm/Support/Compiler.h
> > @@ -21,6 +21,25 @@
> > # define __has_feature(x) 0
> > #endif
> >
> > +#ifndef __has_attribute
> > +# define __has_attribute(x) 0
> > +#endif
> > +
> > +#ifndef __has_builtin
> > +# define __has_builtin(x) 0
> > +#endif
> > +
> > +/// \macro __GNUC_PREREQ
> > +/// \brief Defines __GNUC_PREREQ if glibc's features.h isn't available.
> > +#ifndef __GNUC_PREREQ
> > +# if defined(__GNUC__) && defined(__GNUC_MINOR__)
> > +# define __GNUC_PREREQ(maj, min) \
> > + ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
> > +# else
> > +# define __GNUC_PREREQ(maj, min) 0
> > +# endif
> > +#endif
> > +
> > /// \brief Does the compiler support r-value references?
> > /// This implies that <utility> provides the one-argument std::move; it
> > /// does not imply the existence of any other C++ library features.
> > @@ -146,13 +165,13 @@
> > /// into a shared library, then the class should be private to the
> library and
> > /// not accessible from outside it. Can also be used to mark variables
> and
> > /// functions, making them private to any shared library they are
> linked into.
> > -#if (__GNUC__ >= 4) && !defined(__MINGW32__) && !defined(__CYGWIN__)
> > +#if __GNUC_PREREQ(4, 0) && !defined(__MINGW32__) && !defined(__CYGWIN__)
> > #define LLVM_LIBRARY_VISIBILITY __attribute__ ((visibility("hidden")))
> > #else
> > #define LLVM_LIBRARY_VISIBILITY
> > #endif
> >
> > -#if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
> > +#if __has_attribute(used) || __GNUC_PREREQ(3, 1)
> > #define LLVM_ATTRIBUTE_USED __attribute__((__used__))
> > #else
> > #define LLVM_ATTRIBUTE_USED
> > @@ -166,31 +185,33 @@
> > // more portable solution:
> > // (void)unused_var_name;
> > // Prefer cast-to-void wherever it is sufficient.
> > -#if (__GNUC__ >= 4 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 1))
> > +#if __has_attribute(unused) || __GNUC_PREREQ(3, 1)
> > #define LLVM_ATTRIBUTE_UNUSED __attribute__((__unused__))
> > #else
> > #define LLVM_ATTRIBUTE_UNUSED
> > #endif
> >
> > -#if (__GNUC__ >= 4) && !defined(__MINGW32__) && !defined(__CYGWIN__)
> > +#if __GNUC_PREREQ(4, 0) && !defined(__MINGW32__) && !defined(__CYGWIN__)
> > #define LLVM_ATTRIBUTE_WEAK __attribute__((__weak__))
> > #else
> > #define LLVM_ATTRIBUTE_WEAK
> > #endif
> >
> > -#ifdef __GNUC__ // aka 'CONST' but following LLVM Conventions.
> > +#if __has_attribute(const) || defined(__GNUC__)
> > +// aka 'CONST' but following LLVM Conventions.
> > #define LLVM_READNONE __attribute__((__const__))
> > #else
> > #define LLVM_READNONE
> > #endif
> >
> > -#ifdef __GNUC__ // aka 'PURE' but following LLVM Conventions.
> > +#if __has_attribute(pure) || defined(__GNUC__)
> > +// aka 'PURE' but following LLVM Conventions.
> > #define LLVM_READONLY __attribute__((__pure__))
> > #else
> > #define LLVM_READONLY
> > #endif
> >
> > -#if (__GNUC__ >= 4)
> > +#if __has_builtin(__builtin_expect) || __GNUC_PREREQ(4, 0)
> > #define LLVM_LIKELY(EXPR) __builtin_expect((bool)(EXPR), true)
> > #define LLVM_UNLIKELY(EXPR) __builtin_expect((bool)(EXPR), false)
> > #else
> > @@ -213,7 +234,7 @@
> >
> > /// LLVM_ATTRIBUTE_NOINLINE - On compilers where we have a directive to
> do so,
> > /// mark a method "not for inlining".
> > -#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
> > +#if __GNUC_PREREQ(3, 4)
> > #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
> > #elif defined(_MSC_VER)
> > #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
> > @@ -225,7 +246,7 @@
> > /// so, mark a method "always inline" because it is performance
> sensitive. GCC
> > /// 3.4 supported this but is buggy in various cases and produces
> unimplemented
> > /// errors, just use it in GCC 4.0 and later.
> > -#if __GNUC__ > 3
> > +#if __GNUC_PREREQ(3, 0)
> > #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline
> __attribute__((always_inline))
> > #elif defined(_MSC_VER)
> > #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
> > @@ -267,27 +288,23 @@
> > /// LLVM_BUILTIN_UNREACHABLE - On compilers which support it, expands
> > /// to an expression which states that it is undefined behavior for the
> > /// compiler to reach this point. Otherwise is not defined.
> > -#if defined(__clang__) || (__GNUC__ > 4) \
> > - || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
> > +#if __has_builtin(__builtin_unreachable) || __GNUC_PREREQ(4, 5)
> > # define LLVM_BUILTIN_UNREACHABLE __builtin_unreachable()
> > #elif defined(_MSC_VER)
> > # define LLVM_BUILTIN_UNREACHABLE __assume(false)
> > #endif
> >
> > /// LLVM_BUILTIN_TRAP - On compilers which support it, expands to an
> expression
> > /// which causes the program to exit abnormally.
> > -#if defined(__clang__) || (__GNUC__ > 4) \
> > - || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
> > +#if __has_builtin(__builtin_trap) || __GNUC_PREREQ(4, 3)
> > # define LLVM_BUILTIN_TRAP __builtin_trap()
> > #else
> > # define LLVM_BUILTIN_TRAP *(volatile int*)0x11 = 0
> > #endif
> >
> > /// \macro LLVM_ASSUME_ALIGNED
> > /// \brief Returns a pointer with an assumed alignment.
> > -#if !defined(__clang__) && ((__GNUC__ > 4) \
> > - || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7))
> > -// FIXME: Enable on clang when it supports it.
> > +#if __has_builtin(__builtin_assume_aligned) && __GNUC_PREREQ(4, 7)
> > # define LLVM_ASSUME_ALIGNED(p, a) __builtin_assume_aligned(p, a)
> > #elif defined(LLVM_BUILTIN_UNREACHABLE)
> > # define LLVM_ASSUME_ALIGNED(p, a) \
> >
> > _______________________________________________
> > llvm-commits mailing list
> > llvm-commits at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20130708/76280d4b/attachment.html>
More information about the llvm-commits
mailing list