Re: Make LdrAccessResource Call an Internal Function to Satisfy Shrinker

[Dmitry Timoshkov]

"Robert Shearman" <rob(a)codeweavers.com> wrote:
> -/**********************************************************************
> - * LdrAccessResource  (NTDLL.@)
> - */
> -NTSTATUS WINAPI LdrAccessResource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> -                                   void **ptr, ULONG *size )
> +/* don't penalize other platforms stuff needed on i386 for compatibility */
> +#ifdef __i386__
> +NTSTATUS WINAPI access_resource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> +                                 void **ptr, ULONG *size )
> +#else
> +static inline NTSTATUS access_resource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> +                                        void **ptr, ULONG *size )
> +#endif
>  {
>      NTSTATUS status;
>
> @@ -355,6 +358,30 @@ NTSTATUS WINAPI LdrAccessResource( HMODU
>      return status;
>  }
>
> +/**********************************************************************
> + * LdrAccessResource  (NTDLL.@)
> + */
> +#ifdef __i386__
> +/* Shrinker depends on the "call access_resource" instruction being there */
> +__ASM_GLOBAL_FUNC( LdrAccessResource,
> +    "pushl %ebp\n"
> +    "movl %esp, %ebp\n"
> +    "pushl 24(%ebp)\n"
> +    "pushl 20(%ebp)\n"
> +    "pushl 16(%ebp)\n"
> +    "pushl 12(%ebp)\n"
> +    "pushl 8(%ebp)\n"
> +    "call access_resource\n"
> +    "leave\n"
> +    "ret\n"
> +);
> +#else
> +NTSTATUS WINAPI LdrAccessResource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> +                                   void **ptr, ULONG *size )
> +{
> +    return access_resource( hmod, entry, ptr, size );
> +}
> +#endif

Shouldn't be enough for the __i386__ case just omitting 'inline' in access_resource
definition?

-- 
Dmitry.

Make LdrAccessResource Call an Internal Function to Satisfy Shrinker

[Robert Shearman]

Dmitry Timoshkov wrote:
> "Robert Shearman" <rob(a)codeweavers.com> wrote:
> > -/**********************************************************************
> > - * LdrAccessResource  (NTDLL.@)
> > - */
> > -NTSTATUS WINAPI LdrAccessResource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> > -                                   void **ptr, ULONG *size )
> > +/* don't penalize other platforms stuff needed on i386 for compatibility */
> > +#ifdef __i386__
> > +NTSTATUS WINAPI access_resource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> > +                                 void **ptr, ULONG *size )
> > +#else
> > +static inline NTSTATUS access_resource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> > +                                        void **ptr, ULONG *size )
> > +#endif
> > {
> >     NTSTATUS status;
> >
> > @@ -355,6 +358,30 @@ NTSTATUS WINAPI LdrAccessResource( HMODU
> >     return status;
> > }
> >
> > +/**********************************************************************
> > + * LdrAccessResource  (NTDLL.@)
> > + */
> > +#ifdef __i386__
> > +/* Shrinker depends on the "call access_resource" instruction being there */
> > +__ASM_GLOBAL_FUNC( LdrAccessResource,
> > +    "pushl %ebp\n"
> > +    "movl %esp, %ebp\n"
> > +    "pushl 24(%ebp)\n"
> > +    "pushl 20(%ebp)\n"
> > +    "pushl 16(%ebp)\n"
> > +    "pushl 12(%ebp)\n"
> > +    "pushl 8(%ebp)\n"
> > +    "call access_resource\n"
> > +    "leave\n"
> > +    "ret\n"
> > +);
> > +#else
> > +NTSTATUS WINAPI LdrAccessResource( HMODULE hmod, const IMAGE_RESOURCE_DATA_ENTRY *entry,
> > +                                   void **ptr, ULONG *size )
> > +{
> > +    return access_resource( hmod, entry, ptr, size );
> > +}
> > +#endif
>
> Shouldn't be enough for the __i386__ case just omitting 'inline' in access_resource
> definition?

No. Marcus already discovered with the previous version of 
EXC_CallHandler using the "-funit-at-a-time" option that the compiler 
can re-order the arguments and generally do whatever it wants if we hint 
that it won't be used outside of the module. The compiler is also free 
to generate LdrAccessResource as a simple jump to access_resource, or 
even to just make access_resource point to the same address as 
LdrAccessResource. In short, the only sure way of generating code that 
Shrinker needs is to do it explicitly.

-- 
Rob Shearman