[llvm] r185831 - Use Clang's __has_* macros in Compiler.h to test for features
David Dean
david_dean at apple.com
Mon Jul 8 09:08:46 PDT 2013
This commit has broken some of the buildbots:
http://lab.llvm.org:8013/builders/clang-x86_64-darwin11-nobootstrap-RAincremental/builds/4079
/Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/build.clang-x86_64-darwin11-nobootstrap-RAincremental/llvm/include/llvm/Support/Compiler.h:204:5: error: builtin feature check macro requires a parenthesized identifier
#if __has_attribute(const) || defined(__GNUC__)
^
/Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/build.clang-x86_64-darwin11-nobootstrap-RAincremental/llvm/include/llvm/Support/Compiler.h:204:26: error: expected end of line in preprocessor expression
Please fix or revert as soon as you can.
On 8 Jul 2013, at 8:31 AM, Reid Kleckner <reid at kleckner.net> wrote:
> Author: rnk
> Date: Mon Jul 8 10:31:29 2013
> New Revision: 185831
>
> URL: http://llvm.org/viewvc/llvm-project?rev=185831&view=rev
> Log:
> Use Clang's __has_* macros in Compiler.h to test for features
>
> When targetting Windows, clang does not define __GNUC__, and as a result
> we don't use our attributes with it. This leads to warnings about
> unused functions that are already annotated with LLVM_ATTRIBUTE_UNUSED.
> Rather than testing for __clang__, we can use its __has_attribute and
> __has_builtin macros directlty.
>
> While I'm here, conditionally define and use __GNUC_PREREQ for gcc
> version checks. Spelling the check out with three comparisons is
> verbose and error prone.
>
> Reviewers: aaron.ballman
>
> Differential Revision: http://llvm-reviews.chandlerc.com/D1080
>
> Modified:
> llvm/trunk/include/llvm/Support/Compiler.h
>
> Modified: llvm/trunk/include/llvm/Support/Compiler.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Compiler.h?rev=185831&r1=185830&r2=185831&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Support/Compiler.h (original)
> +++ llvm/trunk/include/llvm/Support/Compiler.h Mon Jul 8 10:31:29 2013
> @@ -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 +165,15 @@
> /// 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__)
> +/// On PE/COFF targets, library visibility is the default, so this isn't needed.
> +#if (__has_attribute(visibility) || __GNUC_PREREQ(4, 0)) && \
> + !defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(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 +187,35 @@
> // 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__)
> +// FIXME: Provide this for PE/COFF targets.
> +#if (__has_attribute(weak) || __GNUC_PREREQ(4, 0)) && \
> + (!defined(__MINGW32__) && !defined(__CYGWIN__) && !defined(LLVM_ON_WIN32))
> #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 +238,7 @@
>
> /// 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 __has_attribute(noinline) || __GNUC_PREREQ(3, 4)
> #define LLVM_ATTRIBUTE_NOINLINE __attribute__((noinline))
> #elif defined(_MSC_VER)
> #define LLVM_ATTRIBUTE_NOINLINE __declspec(noinline)
> @@ -225,7 +250,7 @@
> /// 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 __has_attribute(always_inline) || __GNUC_PREREQ(4, 0)
> #define LLVM_ATTRIBUTE_ALWAYS_INLINE inline __attribute__((always_inline))
> #elif defined(_MSC_VER)
> #define LLVM_ATTRIBUTE_ALWAYS_INLINE __forceinline
> @@ -267,8 +292,7 @@
> /// 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)
> @@ -276,8 +300,7 @@
>
> /// 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
> @@ -285,11 +308,10 @@
>
> /// \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)
> +// As of today, clang does not support __builtin_assume_aligned.
> # define LLVM_ASSUME_ALIGNED(p, a) \
> (((uintptr_t(p) % (a)) == 0) ? (p) : (LLVM_BUILTIN_UNREACHABLE, (p)))
> #else
>
>
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-David
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