On Mon, Jul 2, 2018 at 11:10 AM, Kenneth Graunke <kenn...@whitecape.org>
wrote:
> On Friday, June 29, 2018 5:13:52 PM PDT Jason Ekstrand wrote:
> > These are very similar to the related function in nir_lower_io except
> > that they don't handle per-vertex or packed things (that could be added,
> > in theory) and they take a more detailed size/align function pointer.
> > One day, we should consider switching nir_lower_io over to using the
> > more detailed size/align functions and then we could make it use these
> > helpers instead of having its own.
> > ---
> > src/compiler/nir/nir_deref.c | 91 ++++++++++++++++++++++++++++++++++++
> > src/compiler/nir/nir_deref.h | 6 +++
> > 2 files changed, 97 insertions(+)
> >
> > diff --git a/src/compiler/nir/nir_deref.c b/src/compiler/nir/nir_deref.c
> > index 22ecde4ecca..94f91df5a0f 100644
> > --- a/src/compiler/nir/nir_deref.c
> > +++ b/src/compiler/nir/nir_deref.c
> > @@ -120,6 +120,97 @@ nir_deref_instr_has_indirect(nir_deref_instr
> *instr)
> > return false;
> > }
> >
> > +static unsigned
> > +type_get_array_stride(const struct glsl_type *elem_type,
> > + glsl_type_size_align_func size_align)
> > +{
> > + unsigned elem_size, elem_align;
> > + glsl_get_natural_size_align_bytes(elem_type, &elem_size,
> &elem_align);
> > + return ALIGN_POT(elem_size, elem_align);
> > +}
> > +
> > +static unsigned
> > +struct_type_get_field_offset(const struct glsl_type *struct_type,
> > + glsl_type_size_align_func size_align,
> > + unsigned field_idx)
> > +{
> > + assert(glsl_type_is_struct(struct_type));
> > + unsigned offset = 0;
> > + for (unsigned i = 0; i <= field_idx; i++) {
> > + unsigned elem_size, elem_align;
> > + glsl_get_natural_size_align_bytes(glsl_get_struct_field(struct_type,
> i),
> > + &elem_size, &elem_align);
> > + offset = ALIGN_POT(offset, elem_align);
> > + if (i < field_idx)
> > + offset += elem_size;
> > + }
> > + return offset;
> > +}
> > +
> > +unsigned
> > +nir_deref_instr_get_const_offset(nir_deref_instr *deref,
> > + glsl_type_size_align_func size_align)
> > +{
> > + nir_deref_path path;
> > + nir_deref_path_init(&path, deref, NULL);
> > +
> > + assert(path.path[0]->deref_type == nir_deref_type_var);
> > + nir_deref_instr **p = &path.path[1];
> > +
> > + unsigned offset = 0;
> > + for (; *p; p++) {
>
> Personally, I'd just write
>
> for (nir_deref_instr **p = &path.path[1]; *p; p++) {
>
> since you don't need it after the loop.
>
Good call. Done. The only reason I wrote it the way I did was because the
code I copied it from did it that way. I think there is a good reason
there but not here.
--Jason
> > + if ((*p)->deref_type == nir_deref_type_array) {
> > + offset += nir_src_as_const_value((*p)->arr.index)->u32[0] *
> > + type_get_array_stride((*p)->type, size_align);
> > + } else if ((*p)->deref_type == nir_deref_type_struct) {
> > + /* p starts at path[1], so this is safe */
> > + nir_deref_instr *parent = *(p - 1);
> > + offset += struct_type_get_field_offset(parent->type,
> size_align,
> > + (*p)->strct.index);
> > + } else {
> > + unreachable("Unsupported deref type");
> > + }
> > + }
> > +
> > + nir_deref_path_finish(&path);
> > +
> > + return offset;
> > +}
> > +
> > +nir_ssa_def *
> > +nir_build_deref_offset(nir_builder *b, nir_deref_instr *deref,
> > + glsl_type_size_align_func size_align)
> > +{
> > + nir_deref_path path;
> > + nir_deref_path_init(&path, deref, NULL);
> > +
> > + assert(path.path[0]->deref_type == nir_deref_type_var);
> > + nir_deref_instr **p = &path.path[1];
> > +
> > + nir_ssa_def *offset = nir_imm_int(b, 0);
> > + for (; *p; p++) {
>
> Ditto here.
>
> > + if ((*p)->deref_type == nir_deref_type_array) {
> > + nir_ssa_def *index = nir_ssa_for_src(b, (*p)->arr.index, 1);
> > + nir_ssa_def *stride =
> > + nir_imm_int(b, type_get_array_stride((*p)->type,
> size_align));
> > + offset = nir_iadd(b, offset, nir_imul(b, index, stride));
> > + } else if ((*p)->deref_type == nir_deref_type_struct) {
> > + /* p starts at path[1], so this is safe */
> > + nir_deref_instr *parent = *(p - 1);
> > + unsigned field_offset =
> > + struct_type_get_field_offset(parent->type, size_align,
> > + (*p)->strct.index);
> > + nir_iadd(b, offset, nir_imm_int(b, field_offset));
> > + } else {
> > + unreachable("Unsupported deref type");
> > + }
> > + }
> > +
> > + nir_deref_path_finish(&path);
> > +
> > + return offset;
> > +}
> > +
> > bool
> > nir_remove_dead_derefs_impl(nir_function_impl *impl)
> > {
> > diff --git a/src/compiler/nir/nir_deref.h b/src/compiler/nir/nir_deref.h
> > index 0980bae7215..6f4141aaf82 100644
> > --- a/src/compiler/nir/nir_deref.h
> > +++ b/src/compiler/nir/nir_deref.h
> > @@ -48,6 +48,12 @@ void nir_deref_path_init(nir_deref_path *path,
> > nir_deref_instr *deref, void *mem_ctx);
> > void nir_deref_path_finish(nir_deref_path *path);
> >
> > +unsigned nir_deref_instr_get_const_offset(nir_deref_instr *deref,
> > + glsl_type_size_align_func
> size_align);
> > +
> > +nir_ssa_def *nir_build_deref_offset(nir_builder *b, nir_deref_instr
> *deref,
> > + glsl_type_size_align_func
> size_align);
> > +
> > #ifdef __cplusplus
> > } /* extern "C" */
> > #endif
> >
>
>
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