Jan Vesely <jan.ves...@rutgers.edu> writes:
> On Mon, 2016-06-13 at 17:24 -0700, Francisco Jerez wrote:
>> Serge Martin <edb+m...@sigluy.net> writes:
>>
>> > This fix getting the size of a struct arg. vec3 types still work
>> > ok.
>> > Only buit-in args need to have power of two alignment,
>> > getTypeAllocSize
>> > reports the correct size.
>> > ---
>> > src/gallium/state_trackers/clover/llvm/invocation.cpp | 3 ++-
>> > 1 file changed, 2 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/src/gallium/state_trackers/clover/llvm/invocation.cpp
>> > b/src/gallium/state_trackers/clover/llvm/invocation.cpp
>> > index 03487d6..9af51539 100644
>> > --- a/src/gallium/state_trackers/clover/llvm/invocation.cpp
>> > +++ b/src/gallium/state_trackers/clover/llvm/invocation.cpp
>> > @@ -472,7 +472,8 @@ namespace {
>> > // aligned to the next larger power of two". We need
>> > this
>> > // alignment for three element vectors, which have
>> > // non-power-of-2 store size.
>> > - const unsigned arg_api_size =
>> > util_next_power_of_two(arg_store_size);
>> > + const unsigned arg_api_size = arg_type->isStructTy() ?
>> > + arg_store_size :
>> > util_next_power_of_two(arg_store_size);
>> >
>> Hm... Isn't this still going to be broken if you pass a struct
>> argument
>> to a kernel function and the alignment of any of the struct members
>> doesn't match the target-specific data layout? Not sure we can fix
>> this
>> sensibly without requiring the target's data layout to match the CL
>> API
>> exactly. Any suggestions Tom?
>
> according to 6.7.2.1 compilers can arbitrarily insert padding between
> struct members (except at the beginning).What spec version are you looking at? My CL spec doesn't have any section labeled 6.7.2.1. > Even if size/alignment of individual members match CL API exactly, > there's no guarantee that the structure layout/size will be the same. > How can you exchange structured data with a CL kernel then, assuming that the layout of structure types in memory is fully unspecified as you say? > Jan > >> >> > llvm::Type *target_type = arg_type->isIntegerTy() ? >> > TD.getSmallestLegalIntType(mod->getContext(), >> > arg_store_size * 8) >> > -- >> > 2.5.5 > -- > > Jan Vesely <jan.ves...@rutgers.edu>
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