[Mesa-dev] [PATCH 06/40] glsl: add helper to convert pointers to uint64_t

[Timothy Arceri]

On 10/02/17 21:43, Nicolai Hähnle wrote:
> On 07.02.2017 04:42, Timothy Arceri wrote:
>> From: Timothy Arceri <timothy.arceri at collabora.com>
>>
>> This will be used to store all pointers in the cache as 64bit ints
>> allowing us to avoid issues when a 32bit program reads a cached
>> shader that was created by a 64bit application.
>> ---
>>  src/compiler/glsl/shader_cache.h | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/src/compiler/glsl/shader_cache.h 
>> b/src/compiler/glsl/shader_cache.h
>> index 8bd0a3c..1596c33 100644
>> --- a/src/compiler/glsl/shader_cache.h
>> +++ b/src/compiler/glsl/shader_cache.h
>> @@ -27,6 +27,16 @@
>>
>>  #include "util/disk_cache.h"
>>
>> +static uint64_t inline
>> +ptr_to_uint64_t(void *ptr)
>> +{
>> +   uint64_t ptr_int = (uint64_t) ptr;
>> +#if __i386__
>> +   ptr_int &= 0xFFFFFFFF;
>> +#endif
>
> Is the bit-wise and here really necessary?
Yes. See [1] for an example and the standard and gcc quotes.

[1] 
http://stackoverflow.com/questions/25039796/cast-from-32-bit-address-to-64-bit-integer-yields-unexpected-results

>
> Nicolai
>
>> +   return ptr_int;
>> +}
>> +
>>  void
>>  shader_cache_write_program_metadata(struct gl_context *ctx,
>>                                      struct gl_shader_program *prog);
>>
>