[llvm-commits] [llvm] r71795 - /llvm/trunk/include/llvm/System/Atomic.h

[Nick Lewycky]

Owen Anderson wrote:
> Author: resistor
> Date: Thu May 14 16:24:15 2009
> New Revision: 71795
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=71795&view=rev
> Log:
> Add CompareAndSwap.
> 
> Modified:
>     llvm/trunk/include/llvm/System/Atomic.h
> 
> Modified: llvm/trunk/include/llvm/System/Atomic.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/System/Atomic.h?rev=71795&r1=71794&r2=71795&view=diff
> 
> ==============================================================================
> --- llvm/trunk/include/llvm/System/Atomic.h (original)
> +++ llvm/trunk/include/llvm/System/Atomic.h Thu May 14 16:24:15 2009
> @@ -11,34 +11,70 @@
>  //
>  //===----------------------------------------------------------------------===//
>  
> +#ifndef LLVM_SYSTEM_ATOMIC_H
> +#define LLVM_SYSTEM_ATOMIC_H
> +
>  #include "llvm/Config/config.h"
> +#include <stdint.h>
>  
>  #ifdef __APPLE__
> -#include <libkern/OSAtomic.h>
> +
>  #elif LLVM_ON_WIN32
>  #include <windows.h>
>  #endif
>  
>  
> -#ifndef LLVM_SYSTEM_ATOMIC_H
> -#define LLVM_SYSTEM_ATOMIC_H
> -
>  namespace llvm {
>    namespace sys {
> -    inline void MemoryFence() {
> +    
>  #if !defined(ENABLE_THREADS) || ENABLE_THREADS == 0
> +    inline void MemoryFence() {
>        return;
> +    }
> +    
> +    typedef uint32_t cas_flag;
> +    inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
> +      cas_flag result = *dest;
> +      if (result == c)
> +        *dest = exc;
> +      return result;
> +    }
> +    
>  #elif __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)
> +    inline void MemoryFence() {
>        __sync_synchronize();
> +    }
> +    
> +    typedef volatile uint32_t cas_flag;
> +    inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
> +      return __sync_val_compare_and_swap(dest, exc, c);
> +    }
> +    
>  #elif defined(__APPLE__)
> +    inline void MemoryFence() {
>        OSMemoryBarrier();
> +    }
> +    
> +    typedef volatile UInt32 cas_flag;
> +    inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {
> +      cas_flag old = *dest;
> +      OSCompareAndSwap(c, exc, dest);
> +      return old;
> +    }
>  #elif defined(LLVM_ON_WIN32)
>  #warning Memory fence implementation requires Windows 2003 or later.
> +    inline void MemoryFence() {
>        MemoryBarrier();
> +    }
> +    
> +    typedef volatile long cas_flag;
> +    inline cas_flag CompareAndSwap(cas_flag* dest, cas_flag exc, cas_flag c) {

My GCC complains about this.

In file included from 
/home/nicholas/llvm-commit/include/llvm/Support/ManagedStatic.h:17,
                  from BasicAliasAnalysis.cpp:31:
/home/nicholas/llvm-commit/include/llvm/System/Atomic.h:49: warning: 
type qualifiers ignored on function return type

Because nearly everything uses ManagedStatic this shows up everywhere. 
Please fix.

> +      return _InterlockedCompareExchange(dest, exc, c);
> +    }
>  #else
> -#warning No memory fence implementation found for you platform!
> +#error No memory atomics implementation for your platform!
>  #endif
> -    }
> +    
>    }
>  }
>  
> 
> 
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