[PATCH] Windows implementation of enable_execute_stack

[Aaron Ballman]

On Fri, May 24, 2013 at 5:53 PM, Ruben Van Boxem
<vanboxem.ruben at gmail.com> wrote:
> Hi,
>
> I submitted this patch a long while ago, together with a bunch of other
> changes (some of which got applied back then).
>
> If compiler-rt is in the LLVM tree, a Windows build chokes on this little
> bit.
>
> The relevant test passed back then, but I can't check this right now, as
> LLVM is being difficult (some errors I need to figure out) and compiler-rt
> has since moved to be a subproject requiring the LLVM tree to be built.
>
>
> Please comment or apply. Thanks!
>
> Ruben
>
> PS: I'm not subscribed, please keep me in the CC list
>
> Index: lib/enable_execute_stack.c
> ===================================================================
> --- lib/enable_execute_stack.c (revision 182667)
> +++ lib/enable_execute_stack.c (working copy)
> @@ -10,7 +10,11 @@
>
>  #include "int_lib.h"
>
> +#ifndef _WIN32
>  #include <sys/mman.h>
> +#else
> +#include <windows.h>
> +#endif
>
>  /* #include "config.h"
>   * FIXME: CMake - include when cmake system is ready.
> @@ -38,7 +42,7 @@
>
>  void __enable_execute_stack(void* addr)
>  {
> -
> +#ifndef _WIN32
>  #if __APPLE__
>   /* On Darwin, pagesize is always 4096 bytes */
>   const uintptr_t pageSize = 4096;
> @@ -54,6 +58,14 @@
>   unsigned char* endPage = (unsigned char*)((p+TRAMPOLINE_SIZE+pageSize) & pageAlignMask);
>   size_t length = endPage - startPage;
>   (void) mprotect((void *)startPage, length, PROT_READ | PROT_WRITE | PROT_EXEC);
> +#else

Why not simply #elif defined(_WIN32) and skip the extra level of #ifs?

> +    MEMORY_BASIC_INFORMATION b;
> +
> +    if (!VirtualQuery(addr, &b, sizeof(b)))
> +     exit(1);
> +   if (!VirtualProtect(b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE, &b.Protect))
> +     exit(1);
> +#endif /* _WIN32 */
>  }

Aside from that, patch LGTM.

~Aaron